, . //; ,.
AND ITS
W.H. BOOTH
LIQUID FUEL
AND ITS APPARATUS
LIQUID FUEL
AND ITS APPARATUS
By WM. H. BOOTH, F.G.S.
MEMBER OF THE AMERICAN SOCIETY OF CIVIL ENGINEERS ; FORMERLY
OF THE NEW SOUTH WALES GOVERNMENT RAILWAYS AND
TRAMWAYS, OF THE MANCHESTER STEAM USERS'
ASSOCIATION, OF THE BRITISH ELECTRIC
TRACTION COMPANY, ETC.
SECOND EDITION
NEW YORK
E. P. BUTTON AND COMPANY
PUBLISHERS
Printed in Great Britain ly
BUTLER & TANNER,
Frame and London
O'
TABLE OF CONTENTS
PART I
THEORY AND PRINCIPLES.
PAGE
Preface . . . . . . . . .13
INTRODUCTION
Historical Notes ; Advantages of Liquid Fuel ; Petroleum ;
General Notes ; Economies possible by the use of Liquid Fuel 21
CHAPTER I
The Geology of Petroleum ; Petroleum Drilling ; Pumping . 28
CHAPTER II
The Economy of Liquid Fuel ; The Dangers of Petroleum ; Air
necessary for Combustion ; General Principles of Liquid
Fuel Combustion ; Flame Analysis ; Refractory Furnace
Linings ; The Weir Boiler ; Liquid Fuels ; The necessity for
Atomizing ; Vapourizing ; Varieties of Liquid Fuel ; Ameri-
can Petroleum ; Russian Petroleum ; Creosote Oils ; Tar
Distillates ; Blast Furnace and Shale Oils ... 35
CHAPTER III
Texas Oil ; Analysis of Oil ; Physical Properties ; Russian Oil ;
Calorific Capacity of Oils ; Advantages of Liquid Fuel ; The
Use of Oil on Locomotives ; The World's Oil Production ;
The Limits of Liquid Fuel ; Equivalence of Oil and Coal ;
Tests of Texas Oil 48
CHAPTER IV
Chemical and other Properties of Petroleum ; Water in Oil ;
Petroleums suitable for Fuel; Physical Properties of Petro-
leum ; Specific Gravity of Petroleum ; Materials ; Cast
Iron ; Steel ; Firebricks ; Fireclay ; Clay Analysis ; Special
Forms of Bricks ; Classification of Clay Goods . 62
5
492179
6 TABLE OF CONTENTS
CHAPTER V
PAGE,
Combustibles and Supporters of Combustion." Carbon : its
Forms and Origin ; its Calorific Properties ; its Combustion
and Chemistry. Hydrogen : its Physical and other Pro-
perties ; its Compounds with Carbon ; its Combustion ;
Air ; The Atmosphere ; Properties of Air. Oxygen : its
Compounds with Carbon ; its Properties ; Water ; its
Properties ; Origin and Sources of Water Impurities ; Solu-
bility of Salts ; Sea Water ; Useful Data . . .78
CHAPTER VI
Calorific and other Units ; Thermo Chemistry ; Heat ; Tem-
perature ; Thermometers ; Specific Heat ; Latent Heat ;
Dissociation ; Units of Heat ; Units of Work ; Units of
Weight ; Gravity ; Compound Units ; Calorific Power of
Fuels ; Calculation of Temperatures ; Effects of Dissocia-
tion and of Variation of Specific Heat ; Relative Volumes
produced by Combustion ; Evaporative Power of Fuel ;
Temperatures due to Combustion ; Calculation of Calorific
Capacity of Fuels ; Smoke and Combustion ; Varieties of
Smoke ; Its Prevention ; Influence of Refractory Furnaces ;
The Combustion of Bituminous Fuels ; Carbon Vapour ;
Liquid Fuels ; Furnace Temperatures ; Theoretical Flame
Temperature ; Total Heat generated ; Air Supply ; The
Heat Properties of Carbon ; The Process of Coal Combus-
tion ; Effect of Vaporizing Solid Fuels ; Flame Analysis ;
The Principles of Combustion ; The Necessity of Tem-
perature ; Smoke due to Loss of Heat of Burning Gases ;
The Use of Coloured Glass for Flame Inspection ; The Weir
Boiler ; Ringelmann's Smoke Chart .... 90
PART II
PRACTICE.
CHAPTER VII
Oil Storage on Ships ; Example of Improvised Tank Steamer ;
Example of Cargo Steamer ; Example of New Tank
Steamer ; Use of Liquid Fuel at Sea ; Supply of Oil at
Ports ; Safety and Flash Point ; Advantages for War Ships ;
Economic Advantages of Liquid Fuel . . . .127
CHAPTER VIII
Marine Furnace Gear ; Arrangement of Shell Line Steamers ;
Interchange of Coal and Oil ; The Flannery-Boyd System ;
The Orde System ; Results of Use of Liquid Fuel at Sea ;
Wallsend Slipway Company's Arrangement ; The Lanca-
shire Boiler with Orde's System ; Korting System ; Howden
System .133
TABLE OF CONTENTS 7
CHAPTER IX
PAGE
Liquid Fuel Application to Locomotives ; The Holden System ;
Advantage of Oil ; Method of Working ; Management of
Fire ; Particulars of Oil Burning Locomotive ; Regulation
of Oil Supply ; The Atomizer ; Life of Fire Boxes ; Heating
the Oil ; Air Heater 154
CHAPTER X
"Application of Liquid Fuel to Stationary and other Boilers ; The
Lancashire Boiler ; Cornish Boiler ; Water Tube Boiler ;
Locomotive Boiler ; Level of Atomizer in Mixed System ;
Management of Fire ; United States Navy Tests ; The
Meyer System ; The Mixed System of Coal and Liquid Fuel
Combustion : its use in the Italian Navy ; M. Bertin's
Calculations ....... .167
CHAPTER XI
Russian and American Locomotive Practice ; The Baldwin Com-
pany's System ; The Equivalence of Coal and Oil ; Compari-
sons of Cost of Liquid Fuel ; The Danger of Crude Oil ; The
Urquhart System ; General Arrangements ; Management of
Furnace ; Firebox Designs ; Smoke Results on Grazi and
Tsaritsin Railway . . . . . . . .178
CHAPTER XII
American Stationary Practice with Liquid Fuel ; The Billow
System ; Fuel Oil Pumping Systems ; Double Pumping
Systems ; Furnace Construction ; Operating a Fuel Oil Plant ;
Examples of Boilers with Liquid Fuel Furnaces . . 195
CHAPTER XIII
English Stationary Practice with Liquid Fuel ; The Kermode
System ; Analysis of Borneo Oil ; Tests of Borneo Oil ;
The Hydroleum System ; Tests ; The Sprayer ; Air Supply . 208
CHAPTER XIV
The Combustion of Vaporized Liquids ; The Clarkson-Capel
Burner: its Various Applications; Starting Devices . .218
CHAPTER XV
Comparison of Air and Steam Atomization ; The Ellis and Eaves
System ; Steam Atomization ; Air Atomization ; Tests . 222
8 TABLE OP CONTENTS
CHAPTER XVI
PAGE
The Storage and Distribution of Liquid Fuel ; Tanks ; Piping ;
Ventilation ; Great Eastern Railway System ; Grazi and
Tsaritsin Railway System ; Oil Pumps ; Flue Gas Analysis ;
Calculation of Volumes ; The Orsat Apparatus ; CO 2
Recorders ; Calorimetry and Draught ; Calorimetric Deter-
minations ; Draught ; Gauges ; Difference of Solid and
Liquid Fuel in Relation to Draught . . . .228
CHAPTER XVII
Compressed Air ; Air Compressors ; Principles of Compression ;
Weight of Air necessary for Liquid Fuel Atomization ; Adia-
batic Calculation of Air ; Compound Air Compression ;
Volumetric Efficiency ; Power to Compress Air ; Outflow of
Air . . 242
CHAPTER XVIII
Atomizing Liquid Fuels ; Various Atomizers ; Elementary Forms ;
Vaporizers ; The Symon-House Burner ; Atomizing Agents ;
French Trials ; Air Compression ; Certain Advantages of
Steam ; d'Allest Atomizer ; Fvardofski System ; Russian
Atomizers ; Object of Atomizing ; American Practice . . 250
CHAPTER XIX
Application of Liquid Fuel to Metallurgy ; The Hoveler System . 266
CHAPTER XX
The Oil Engine ; The Diesel and other systems . . .270
PART III
Tables and Data . 281
INDEX TO ILLUSTRATIONS
FIG. PAGE
0. Hypothetical Section of Oil-bearing Strata ... 30
1. Kiln Furnace ........ 74
2. Form of Baffle 74
3. Brick Fire Arch 75
4. Shaped Bricks 76
5. Shaped Bricks 76
6. Unshaped Arch Bricks . . . . . . .76
7. Weir Boiler 121
8. Ringelmann Smoke Chart 122
9. Furnaces, s.s. Murex ....... 134
10. Furnace Brickwork, s.s. Murex . . . . .135
11. Furnace, s.s. Trocas 136
12. Service Tank, Flannery-Boyd System . . . .137
13 and 13a. s.s. New York 138
14. Water Tube Boiler, Orde's System . . . .141
14a. Fuel Bunker, Draw-off Pipe 142
15. Orde's Atomizer ........ 144
16. Detail Arrangement for Lancashire Boiler, Orde's System . 145
17 and 17a. Design for Oil Furnace, Wallsend System . 146
18. Wallsend Pressure Burner . .148
19. Diagrammatic Arrangement, Wallsend System . .150
19a. Detail Arrangement, Wallsend System . . . .150
20. Water Tube Boiler, Wallsend System . . . .151
21. Furnace, s.s. F. C. Laeisz . 152
22. Atomizer, Korting System . . . . . .153
22o. Atomizer, Korting System . . . . . .153
23. Great Eastern Locomotive, Atomizer, Holden's System . 158
24. Atomizer, Form (1911), Holden's System . . .159
25. Atomizer, Locomotive Type, Holden's System . .160
26. Great Eastern Locomotive, Holden's System, Firedoor . 161
27. American Locomotive Firebox for Liquid Fuel . .163
28. Great Eastern Locomotive . . . . . .165
29. Lancashire Boiler, Holden's System . . . .168
30. Water Tube Boiler without Grate, Holden's System . 169
31. MacAllan Variable Blast Pipe Cap . . 170
32. Locomotive Boiler, Southern Pacific R.R. . . .171
33. Meyer System 173
34. Atomizer, Baldwin System . . . . . .179
35. Oil Regulator, Baldwin System 179
36. Locomotive Firebox, Baldwin System, Old . . .180
37. Locomotive Firebox, Baldwin System, New . . .181
10 INDEX TO ILLUSTRATIONS
FIG. PAGE
38. Goods Locomotive, Urquhart System . . . .188
39. Goods tender, Urquhart System . . . . .190
40. Firebox, Urquhart System . . . . .191
41. Locomotive Firebox, Urquhart System . . . .192
42. Atomizer, Urquhart System . 193
43. Locomotive Performance Chart, Urquhart System . .194
44. Atomizer, Billow System . . 196
45. Double Pumping System, Billow . . . 198
46. Tuyere, Billow System 199
47. Tuyere Block, Air Regulator, etc., Billow System . . 200
48. Tank Car Hose Connection ... .201
49. General Furnace Mouthpiece Arrangement, Billow System 202
50. Underfired Boiler, BiUow System 205
51. Water Tube Boiler, Billow System . . . .206
5 la. General Arrangement, Billow System .... 207
52. Liquid Fuel Furnace, Kermode's System . . . 209
52a. Enlarged Details, Kermode's System . . . .210
53. Furnace Arrangement, Kermode's System . . .211
54. Furnace Arrangement, Kermode's System, Babcock Boiler 213
55. Furnace Arrangement, Hydroleum System . . .215
56. Furnace Arrangement, Hydroleum System . . .216
57. Clarkson-Capel Burner for Fire Float . . . .219
58. Clarkson-Capel Burner for Automobile .... 220
59. Air Heater, Ellis and Eaves System .... 223
60. Ellis and Eaves Furnace Door 223
61. Oil Supply Tank 231
62. Weir Pump . . . .232
63. Diagram of Adiabatic Compression. .... 244
64. Diagram of Compound Compression with Intercooling . 244
65. Atomizer, Hoveler System ...... 267
66. Atomizer, Rusden-Eeles 251
67. Atomizer, Aerated Fuel Process ..... 252
68. Atomizer, Kermode's Pressure System . . . .253
69. Atomizer, Kermode's Hot-Air System .... 254
70. Atomizer, Kermode's Steam System .... 255
71. Atomizer, Hydroleum System ..... 255
72. Atomizer, Elementary Form ...... 256
73. Atomizer, Swensson . . . . . . .256
74. Symon-House Vaporizer . . . . . .257
75. Atomizer, Guyot ........ 258
76. Atomizer, Nozzle Incorrect Form ..... 259
77. Atomizer, Nozzle Correct Form . . . . .259
78. Furnace of French Torpedo Boat No. 22 ... 260
79. Atomizer, d'Allest 261
80. Atomizer, Double, d'Allest 262
81. Atomizer, Soliani . . . . . . . 263
82. Torpedo Boiler tried at Cherbourg .... 264
82a. Assembly of Gregory's Fuel Oil Burner .... 265s
83. Hornsby-Akroyd Engine . . . .272
84. Cross Section, Vaporizer, Hornsby-Akroyd . .273
85. Griffin Engine Vaporizer . . - .276
INDEX TO TABLES
TABLE PAGE
I Composition of Crude Oils 281
II Calorific Capacity of Liquid Fuel Oils . . .281
III Coefficient of Expansion of Crude Oil . .281
IV Calorific Capacity of Crude Oil .... 284
V Table of the Properties of Gases (Kempe) . . 282
VI Temperature Table 284
VII Specific Heat of Gases 284
VIII Equivalents, Various 285
IX Calorific Properties of Carbon .... 285
X Tension of Aqueous Vapour . . . . .286
XI Relative Economy Oil and Coal .... 286
XII Russian and Pennsylvanian Oils, Analysis of . . 286
XIII Comparative Trials of Petroleum Refuse . .287
XIV Conversion Table, Degrees Baume .... 288
XV Heat of Combustion (B. Th. U.) und Air per Pound
of Fuel . . 288
XVI Theoretical Flame Temperatures . . . .289
XVII Weight and Volume of Gases . . . .289
XVIII Weight and Volume of Oxygen and Air for Combustion.
Metric 290
XIX Weight and Volume of Oxygen and Air for Combustion.
English 290
XX Theoretical Evaporative Value of Petroleum and Coal 291
XXI Ignition Temperature of Gases .... 292
XXII Conversion Tables for Evaporation and Combustion 292
XXIII Temperature Determination by Fusion of Metals . 293
XXIV Volume and Weight of Dry Air . .293
XXV B. Th. U. in Water . * , . .294
XXVI Saturated Steam Data ... . 294
XXVII Factors of Evaporation ... .295
XXVIII Heat Balance Table ... . 296
XXIX Heat Lost in Chimney Gases (Diagram) - 297
PREFACE TO LARGER EDITION
OF 1903
subject of Liquid Fuel is one that has now been before
X the public about twenty-five years, but little had been
done in this country until about twelve years ago, when Mr.
Holden, of the Great Eastern Railway, began to use the tar
of his oil-gas process, and found many advantages in using
this hitherto almost unsaleable product. The success of this
tar led him on to the use of creosote and other hydrocarbon
by-products, and now he is using Texas oil.
In this book the Author has endeavoured to put together
what has been done in the burning of liquid fuel, and at the
risk of repetition has given descriptions of various systems and
apparatus ; and while no statements have been accepted
unconsidered, he has not hesitated to use descriptions and
statements of manufacturers in some cases with little altera-
tion where such statements were sound and reasonable. The
Author is not only indebted to the many whose names appear
in the text, but also to many others who have furnished him
with information, particularly Professor W. B. Phillips, Ph.D.,
of the University of Texas, from whose bulletins the Author
has drawn so copiously for information on Texas oil ; to Mr.
Thomas Urquhart, of Dalny, who, as Locomotive Superin-
tendent of the Grazi and Tsaritsin Railway, first placed liquid
fuel burning on a sound basis in locomotive work, and whose
papers on the subject may be found in the Proceedings of
the Institution of Mechanical Engineers ; to his friend Mr.
B. H. Thwaite, whose researches in combustion have been so
extensive.
The work of the United States Naval Department, under
Rear-Admiral Melville, has been so valuable that special
appendices have been devoted to a copious abstract of the
coal and oil tests made by the Bureau of Steam Engineering
upon a water-tube boiler as well as tests upon the s.s.Mariposa
The Author has also drawn liberally upon the bulletins of
the U.S. Geological Survey for information on petroleum
production.
13
14 PREFACE TO LARGER EDITION OF 1903
To Mr. Alfred J. Allen acknowledgment is due for informa-
tion on tar and creosote, and for tabular matter to Mr. Poole,
whose excellent treatise on the Calorific Power of Fuels deals
so exhaustively with coal.
Appendices are added giving the Rules of the National
Board of Fire Underwriters (U.S.), and also the Rules of
Lloyd's Register of Shipping.
Acknowledgments are due to the Electrical Review (London)
for permission to reproduce portions of the Author's articles
in that Journal on questions of combustion. To Mons. L.
Bertin, of the French Navy, the Author is indebted for infor-
mation as to the use of liquid fuel in the French Military Marine.
The means for utilizing Liquid Fuel are very varied, yet
all practically result in, or at least aim at, one end. It has
been impossible within two covers to do more than select a
number of such apparatus to illustrate the principles which
have been followed in achieving success. The successful com-
bustion of liquid hydrocarbon is but an extension of the prin-
ciples necessary for bituminous or hydrocarbon coal. The
difference is that coal is burned partly upon the grate, and air,
to burn the hydrocarbon distillates, cannot well be introduced
from below, as it can with liquid fuel which is burned in a
floating condition, and can be fed with air from below very
easily.
The difference is but one of degree, but with liquid fuel the
fact that all the fuel is floating, and would produce a specially
foul black smoke under the conditions in which coal is burned,
has compelled the adoption of means that ought to be adopted
with coal-fired furnaces.
The Author has endeavoured to connect the two practices,
for in the present state of liquid fuel supply it is more than
probable that its use will be parallel with the use of coal,
especially hi dealing with the sudden and high load peaks of
electric stations. Liquid fuel cannot be universal unless the
supply increases to many times what it is at present, and
this points to a good future for the mixed system of firing,
oil and coal being burned together in the same furnace.
It has been difficult to make a selection of apparatus to be
described, but the Author trusts that he has selected a suffi-
cient number of types practically to cover the ground and
show the general trend of practice without unduly multiplying
examples. Indeed the tendency seems to him to be in the
direction of one general type. As regards special boilers, oil
does not appear to require anything more than what is re-
quired by coal, though coal is not treated to the necessary
PREFACE TO LARGER EDITION OF 1903 15
appliances, and oil is so treated, and gains success where coal
is allowed to fail.
Much that perhaps ought to appear in such a book as this
has been omitted, as it appears to the Author that the question
of draught, for example, is not of the same importance with
liquid fuel as it is with solid fuels.
More might be said on the subject of flue-gas proportion, but
this again has been so fully treated by other writers that it
did not seem desirable at present to deal with it more fully.
The most important detail of liquid fuel apparatus is the fur-
nace and the provision of air, and of means to secure combus-
tion and conserve temperature to enable combustion to be
made perfect.
Mr. Horace Allen kindly revised the section on gas analysis.
Students of liquid fuel combustion will find enormous masses
of information in the past volumes of the Engineer, Engineer-
ing, and other technical papers. Much of this information
is duplicated and historical, and the Author has found it
necessary to eliminate almost all such matter and confine his
space to systems now living or of recent use, or of a form recog-
nized as useful to-day. Undoubtedly Aydon and the late
Admiral Selwyn did much to urge the use of liquid fuel, but
the latter injured the value of his best work by regarding
steam as a combustible.
The Author is also indebted to Messrs. Colonner and Lordier,
the French engineers, for excellent information on liquid
fuel, and indirectly no doubt to many others who are not
directly traceable.
Finally, his grateful acknowledgments are due to his Pub-
lishers for the manner in which they have facilitated his labours
throughout.
WESTMINSTER.
PREFACE
THE object of this book is to present in a handy form the
more immediate practical points of the Author's larger
work on the same subject. 1
In that book the Author endeavoured to present not merely
the subject of liquid fuel combustion but such side issues as
water softening, and considerably more on the general theory
of combustion and the physical properties of materials than
can be found room for in this present work.
The larger work is still available for those who may desire
the fuller presentation of the subject, but it was written at a
time when the popular idea of liquid fuel was very hazy, and
when the world's production of petroleum was very much less
than it is to-day. The ideas then presented by the Author
have since received very general acceptance. Over parts of
the world liquid fuel will continue to take the place of coal.
In other parts it will be used because by its means things may
be accomplished that would not be possible with coal. This
was amply demonstrated during the naval manoeuvres a year
or two ago, when the stokehold crew of one of the rival fleet
divisions were worn out and unfit for further effort. Liquid
fuel was then resorted to and the ships simply ran away from
the " enemy " and ravaged the south coast.
Much of what appears in the larger work is eliminated
because of the foregoing reasons as well as the fact that the
subject of liquid fuel is now quite removed from controversy
and has entered more fully upon the commercial stage, for
liquid fuel will now be used wherever it is cheaper than coal
or possesses circumstantial advantages which outweigh expense.
For the peak loads of electric light supply undertakings liquid
fuel presents itself so favourably that only surprise can be felt
that this particular field has so far been neglected.
This book will therefore be fairly closely confined to the
use of liquid fuel in steam raising and in direct power produc-
tion in the internal combustion engine. This engine has in
the last few years made great advances and bids fair soon to
1 Liquid Fuel and Its Combustion. Constable & Co., 1902.
17 B
18 PREFACE
find itself employed as the motive power producer in ships of
great size and tonnage.
While bringing up to date the examples of apparatus these
have been reduced in number. Tabular matter has been
abridged in numbers and detail and much experimental record
has had to be cut out in order to bring the book within its
intended compass.
Finally it may be added that since the issue of the Author's
larger book, there has been little change in the methods or
apparatus employed, though there is a steady extension,
chiefly abroad, in the uses to which liquid fuel has been put.
The Author trusts he has given sufficient examples of
apparatus to enable any engineer to adapt liquid fuel to his
own conditions. He wishes to make it clear that the examples
and illustrations are chosen as examples and are not put
forward as being other than typical. It is not possible to
make a book into a complete catalogue of apparatus, and
only a few can be selected as types.
WM. H. BOOTH.
38, BROAD STREET AVENUE, E.G.
Oct., 1911.
There is still a big field for the use of systems of mixed
solid and liquid fuel, as carried out notably with the Gregory
burner described in Chapter XVIII. (June, 1921.)
Part I
THEORY AND PRINCIPLES
INTRODUCTION
THE first really practical and efficient employment of
liquid fuel for steam-raising purposes appears to be
due to Mr. Thomas Urquhart, of the Grazi and Tsaritzin Rail-
way of Russia. Mr. Urquhart used the spraying system and
obtained good results, and his paper of 1884 1 marks the
beginning of the period of really useful work.
The application of liquid fuel in the Caucasus owes its success
to a combination of causes. Russian petroleum has less light
oil in its composition, and therefore produces more astatki,
i.e. mazut or residuum ; coal is dear in the district, and the
man was present in Mr. Urquhart to render the application of
liquid fuel successful, previous applications not having proved
so.
Urquhart placed the use of liquid fuel on a sound basis.
The Chicago Exhibition in the early nineties gave great
impetus to the use of liquid fuel in America, for all the boilers
there were arranged with oil fuel only.
In Great Britain the use of liquid fuel has not been extensive,
but it has been marked by good practice, and only bids fair
to become extensive since the introduction of mineral oil.
Previously the tendency had been to use the products of distil-
lation of coal or oil in the shape of tars or creosotes.
To-day liquid fuel is well established and recognized as a fuel
of extreme elasticity, and one that can be burned smokelessly.
The days of experiment are past, and no serious difficulties
remain to be overcome. Since 1902 liquid fuel has been
adopted in the British Navy, and it is understood that very
satisfactory results have been secured.
At the same time the question must be considered from a
conservative standpoint, because for years to come, if ever, the
output of petroleum will not be sufficient to make it a serious
rival of coal in every use. There is no certainty of extensive
petroleum production in the future. Petroleum wells do not
endure indefinitely. They are not like water wells, fed from
1 Institution of Mechanical Engineers, Minutes of Proceedings, 1884.
21
22 LIQUID FUEL AND ITS APPARATUS
surface rainfall, and geology does not assure us that they are
being fed from still deeper sources, nor is it decided whether
petroleum is of mineral or of organic origin. The future of
petroleum is thus uncertain.
GENERAL CONSIDERATIONS
A general idea of the liquid fuel problem should therefore
be obtained before attempting to gauge its merits.
There is a lack of the sense of proportion in many who
discuss the question of liquid fuel.
In Great Britain alone over 250 million tons of coal are
raised each year. In the United States the amount is still
greater. The present production of mineral oil is a mere
fraction of the millions of tons of coal produced in the world.
Liquid fuel has undoubted advantages in many cases, and
probably nowhere could it be used to better advantage than
in an electric light station.
One of the principal advantages of oil is its high calorific
value per pound. This, with the best oils, is double the
capacity of the inferior coals, and 30 per cent, better than the
best coal. The ease with which it can be stored and moved
from point to point is an advantage. It can be fired mechani-
cally, makes no ash or clinker, can be burned at maximum rate
or entirely turned off in a moment. Further, a very large
power of boilers requires very little labour in the stokehold.
Petroleum consists of a very large variety of constituents,
gaseous, liquid, or solid. The gas is marsh gas, CH 4 , and at
once disappears ; the lighter liquids are very volatile, and
finally there are solid bodies at the end of a long series of
liquids of varying degrees of volatility and specific gravity.
The chemical formulae which cover most of the constituents
of petroleum are C n H 2n and C n H 2n 2. These formulae con-
tinue throughout the whole range from marsh gas, CH 4 ,
onwards.
Texas oil is used chiefly as it is found.
Russian oil is used in the form of astatki, the residuum after
distilling off the lighting and lubricating oils. Much of the
American oil is also used in the form of residuum.
The proportion of carbon in all the liquids used as fuel varies
very little from 84 per cent., the hydrogen amounting to 16
per cent. There is little else, so that petroleum is practically
all combustible.
It is well established that there is at present only one way
to burn liquid fuel for steam raising, and that is by atomizing
the fuel in company with & sufficient amount of air around
INTRODUCTION 23
each atom. In order that oil may atomize freely, it should be
deprived of viscidity by heat. Heat also causes any water
in the oil more easily to separate out, first, because heated oil,
being more limpid offers less resistance to the freeing of the
water ; and secondly, there is greater expansion of oil than of
water due to the heat, and the water gains a relatively greater
specific gravity.
Warming is done by a steam coil, and may be merely local
warming in the vicinity of the take-off valve in the tank. It
is essential that water be fairly well separated, because if it
comes through the burners in any quantity it may extinguish
the fires, and the next following oil is apt lo ignite explosively.
In storing oil there is always apt to be some vapour given off,
and an empty tank ought not to be entered with a light.
Though not nominally of double the calorific capacity of
average fair coal, oil is found in practice to be worth double the
price of coal, owing to the labour cost which it saves.
This is as regards marine service, for the oil can be carried in
ballast tanks, and paying cargo is carried in the coal bunker
space.
For land purposes, these latter considerations do not weigh,
and the relative values must be based on the performance
ratio of about 16 to 10, together with the economy of labour,
cleaning, ash cartage, etc.
Above and beyond all these things, however, is the power
which liquid fuel gives of immensely increasing the steam-
production of a boiler at short notice.
In general practice a steam-boiler is designed with a given
ratio of heating surface per unit of fuel burned. Any reduction
of this ratio is accompanied by a poorer performance. Less
steam is produced per pound of oil consumed. A reduction of
the heating surface ratio does not, however, reduce the per-
formance by anything like the same ratio.
If a large demand for steam is made upon a boiler for a short
fraction of its working hours, it may be cheaper to consume
fuel at a high rate for a fraction of the time than to employ
two or even three boilers at normal rates during a fraction of
the day, the extra boilers remaining idle during the rest of the
day ; albeit when the heavy load is past these extra boilers
are retired hot and full of energy. The saving by the first
method is very considerable in respect of space occupied, build-
ings and capital cost generally, and if not carried too far it
will outweigh the fuel cost of the short run at heavy output.
For this system of working, coal can, of course, be employed.
Coal, however, cannot be fired at abnormal rates with special
24 LIQUID FUEL AND ITS APPARATUS
ease. A mechanical stoker does not readily increase its rate
of working. The better forms of stoker on the coking prin-
ciple cannot put their whole grate surface into the new and
forced condition. The sprinkler class, again, do not work
well at abnormal rates. Coal combustion is only to be regu-
lated by draught intensity. With oil, the supply is instantly
variable to suit the steam required, and a boiler can rapidly
give its fullest output. With boilers of the smaller tube type
especially, their small water contents enables the engineer to
leave them standing cold to within a short time of maximum
output. Oil is then turned on, and in a few minutes the boiler
is in full work. When a boiler is already at work the mere
turn of a handle puts it into its maximum steam-producing
condition.
So soon as the demand ceases the oil can be turned off, and
the normal coal fire continued, or the boiler laid off entirely.
By means of liquid fuel great elasticity is possible.
In a lighting station the load factor is very usually about 12
per cent. That is to say, about one-eighth of the plant is, on
the average, at work all the working hours.
This excessive misproportion is remedied to any desired extent
by means of accumulators, but it is not yet commercially
economical to instal so high a proportion of battery power as
to enable the power-plant to run at steady load all day. The
peak of the load, however short in duration, cannot be sur-
mounted without the aid of power, and it is to the height and
small duration of the maximum load curve that the poor load
factor of a lighting station is due. Accumulators for heavy
output of short duration greatly improve the load factor, but,
in any case, the number of boilers at work to tide over the peak
is several times the mean number.
If, by means of liquid fuel, boilers can be heavily pushed
for two. three, or four hours, the capital outlay on boilers will
be much reduced. When the various points are taken into
account, the boiler scheme that will probably suggest itself
will be, first, some boilers of the Lancashire type, economical
and steady steamers ; secondly, large tube boilers with a
moderate water contents and large grate area, and with efficient
steam driers or superheaters. These boilers can be heavily
forced with some sacrifice of economy, but the priming due to
heavy forcing must be eliminated by a good superheater. This
is essential to economy. Thirdly, small tube boilers of very
small water capacity, capable of being heavily forced, delivering
their steam preferably above water level in the steam drum.
If all these boilers are fitted with oil sprayers, the maximum
INTRODUCTION 26
demand for steam will be met with the minimum of capital
outlay.
It is a fallacy to suppose that boilers of small water capacity
respond most readily to a sudden demand for steam.
When a boiler is at work under full pressure, the whole of its
water is at a temperature which corresponds with the pressure.
Any addition to the furnace activity cannot add to the hea'o
contents of the boiler, unless the pressure is allowed to rise ;
obviously, therefrom, given the continuance of the same pres-
sure, the boilers of large water contents will answer to an urged
fire just as rapidly as a boiler of small water contents. When
boilers are standing at rest, however, and cold, the boiler which
contains the least water will, ceteris paribus, become most
quickly hot. Such a boiler as the Solignac, which holds almost
no water, can be made, by aid of oil fuel, to produce its maxi-
mum power in a few minutes after lighting up.
In this respect oil has a decided advantage over solid fuel.
To secure a good fire with solid fuel there must be a thick bed
of incandescent fuel on the grate, and this can only be built
up with comparative slowness, and when its duty is over it
remains a more or less wasted force. With oil, however, the
maximum fire is instantaneous, and the only drawback is the
cold brickwork of the setting, which must become hot before
the maximum furnace duty is attained.
For ordinary economical work the number of heat units that
a boiler can absorb per square foot of heating surface will not
be changed when liquid fuel is employed, except so far as liquid
fuel can be burned without smoke more easily than can solid
hydrocarbons, such as coal, and thereby the heating surface
is maintained clean and free from dust and soot, and more
efficient. Evaporative efficiency must not be allowed to out-
weigh the overall, or commercial, efficiency. Exactly what
governs the relation between evaporative and commercial
efficiency cannot be stated positively. Indeed, commercial
efficiency alone should be considered as the true basis of design.
It may, however, be stated in general terms that plant which
is on duty for long hours may be designed to work more economi-
cally as regards fuel than plant intended to work very short
hours.
Let it be assumed that the boilers which are economical of
fuel have an efficiency of 72 per cent., and that the small highly
pushed boilers are run at 60 per cent, efficiency for three hours.
Then, in course of a year, fuel is wasted which represents 12
per cent, difference of efficiency lost for three hours daily.
To enable this loss to be avoided there would be so many
26 LIQUID FUEL AND ITS APPARATUS
thousands of pounds extra capital cost in boilers, buildings,
etc., and where oil is not employed, so much more labour cost
as compared with oil. Properly equated at a suitable rate of
interest and depreciation, the relative value of the alternative
systems may be found after the manner of the Kelvin law
applied to cable work. In many stations the extra labour
for the heavy duty period is difficult to arrange satisfactorily.
Men are employed more hours than they really work, and where
it may be best to use coal for 10 hours, the labour cost may
make it cheaper to use oil for 4 hours of a peak load, even if,
in mere fuel cost per unit, the oil is more expensive.
Trials with liquid fuel show that there is still much to be
done in reducing the air supply. The air required to burn 1
unit weight of carbon is 11 J units. An ordinary oil fuel re-
quires fully 15 units, with, of course, some additional excess
as with solid fuel. But with oil fuel there ought to be better
mixture of air and fuel, and therefore better combustion with
less excess of air.
If we regard air as the fuel and coal or oil as the sustainer of
combustion, as we have a chemical right to do, we shall arrive at
the conclusion that, approximately, the calorific value of a fuel
in actual duty done will not differ much from the chemical
ratio of air required in the combustion process. The large
amount of air per pound of oil arises from the large percentage
of hydrogen in the oil, and it is the large capacity for oxygen
possessed by hydrogen which renders the theoretical tem-
perature of combustion so nearly like that of carbon, in spite
of the high calorific capacity of hydrogen.
As regards the production of petroleum, that of the United
States in the year 1901 was 69,389,194 barrels, valued at 66 J
million dollars. If each barrel is assumed to contain 360 lb.,
or say 6 barrels per ton, the total tonnage will be 11,565,000,
and the value, therefore, something under 23<s. per ton, or prac-
tically $1 per barrel. Thus the weight of oil produced in the
United States was about 5 per cent, of the weight of coal, or
say 7J per cent, of the calorific capacity. After the removal
of the lighting and lubricating oils, the amount of fuel oil
remaining was quite small as compared with the coal output.
It may be assumed that the total oil production of the world
is not 5 per cent. 1 of its coal production. Any idea of
entirely displacing the coal must be out of the question, unless
the yield of oil be increased beyond present prospects, and the
use of fuel must therefore be undertaken with common-sense
1 1921. The ratio is now about 10 per cent.
INTRODUCTION 27
caution, and not in any wholesale manner, to the expected
exclusion of coal.
At the same time, when the limitations of the subject are
recognized, it cannot be denied that liquid fuel lends itself to
certain conditions as to steam raising which must render it
extremely valuable and of great convenience. Marine work
and electrical work are, par excellence, the two lines along
which liquid fuel appears likely to advance most successfully,
and in the author's opinion steam-driven motor cars may
eventually discard the dearer oils and employ the heavy oils
and residuum as fuel by means of atomizers. According to
present appearances, the motor car or tractor offers one of the
finest fields for the use of the heavy fuel oils, as distinguished
from the petrols or even the cheap lamp oils, such as are already
used on steam cars. Little has yet been done in this direction.
It may, however, be added that the commoner grades of para-
ffine are at present so cheap that such vehicles as steam omni-
buses are not tempted to depart from paraffine in favour of
heavier oils. Such cheapness appears to arise from fighting
competition, and if so will not last.
1921. Much was done quietly during the war by way of
introducing liquid fuel throughout the Navy. The pressure-
jet system of atomization by high pressure came well to the
front. This atomization through small whirl passages of
course demands good heating and filtration and it is about
10 per cent, superior in economy to air or steam systems.
As an example of what oil will do may be cited the case
of a 6,000 i.h.p. destroyer of 30 knots and 350 tons, which
burned 139 pounds of coal per 100 ton-miles, whereas a later
34-knot boat of 800 tons and nearly 18,000 i.h.p. burned only
83 pounds of oil per 100-ton miles. More duty per ton-mile
is of course to be expected in a bigger vessel, but the com-
parison is notable. In the U.S. Navy oil and coal have been
found to have a relative evaporation of 1445 and 9-31.
CHAPTER I
THE GEOLOGY OF PETROLEUM
IN this book very short reference only is needed to the sub-
ject of the Geology of Petroleum and the method of
procuring it.
Petroleum is found in various geological formations, from
the Silurian and Carboniferous in the United States, to the
Tertiaries in the eastern hemisphere. It indicates its presence
sometimes by the escape of inflammable gas at the surface,
sometimes by the existence of deposits of pitch or asphaltum,
as at La Brea in Trinidad, where a large lake of pitch has been
recently proved to have indicated petroleum below. Some-
times petroleum oozes from surface outcrops. Where there
are no surface indications petroleum may be inferred to exist
where the geological conditions resemble those of known and
proved fields. But no geological knowledge can go beyond
this. In a proved field there is greater certainty of success
along any particular line of country with each successful boring
that has been made along that line.
Petroleum is very usually found to lie along an anticlinal
fold, more or less inclined, the oil having been forced into
such ridged or domed formations by the superior gravity of
water pressure behind it. A natural sequence of this is that,
when an oil well becomes exhausted, the oil is frequently
succeeded by a flow of water often salt.
This frequent presence of salt water with petroleum lends
colour to the supposition that petroleum is of marine origin,
and formed by the action of heat and pressure on marine
organisms of animal or vegetable origin.
Porous "strata are the most favourable for the storage of oil
owing to their porosity. When overlaid by impermeable beds
of clay, gas usually accompanies the oil when first struck.
When oil occurs in clay, as in the oil shales of Scotland and of
New South Wales and in the Kimeridge Clay of England, the
clay has merely absorbed the oil and holds but a comparatively
small quantity. The gas has often escaped. At Heathfield in
28
THE GEOLOGY OF PETROLEUM
Sussex the author bored a well in 1896 for the London and
Brighton Railway Co., upon an anticlinal fold of the Weald.
Very little water was found, but gas at considerable pressure
had been enclosed by the impermeable dome, and has since
been used to light the Company's station. But the oil with
which it is associated is probably only that small amount which
was proved by the subwealden boring in Limekiln Wood,
near Battle, and has long been known to be contained in the
Kimeridge Clay which has for years been worked for oil at
Wareham in Dorsetshire.
Surprise is sometimes expressed that within a small distance
of each other some borings yield good supplies of oil, while
others close by are barren. But we cannot know the hidden
geology of any area, even if the surrounding outcrops appear
to point to continuity and conformity. Thus who was to
know, until the classical bore-hole was made at Meux's brewery
in Tottenham Court Road, London, that when the lower
Greensand was being deposited in a salt sea the site of London
was an uprising above sea level of a mound or ridge of Devonian
rock, so that the greensand Sea extended only to a point under
the above brewery. Take the map of Ireland and look at the
deep indentations of the south-west coast, Bantry Bay, Dingle
Bay, the Kenmare River and Dunmanus Bay. Imagine this
area gradually to sink deep below sea level and to be wholly
covered with clay. Then according as a bore- hole was put
down from the surface above what is now hard rock, or above
what is now the sea, so would the thickness of the surface
stratum of clay vary by many hundred feet. The cliffs being
vertical in places, this difference of thickness might occur in a
distance of a few feet. A fault would possibly be declared to
exist, whereas the difference would merely be due to the ancient
marine action, which has left standing these upturned hard
rocks whose synclinal folds may have an equal dip below the
waves that the anticlinal folds have a rise above them. Such
natural features as appear in present day surface geology may
be fairly assumed to have formed the ancient floor on which
more recent strata have since been deposited.
The presence of oil in any stratum does not necessarily in-
dicate that it was formed in that stratum. It may have found
its way there by reason of the superincumbent pressure of the
overlying strata, or it may have reached such stratum vaporized
by heat and there condensed to liquid. Or again, it may have
been forced to leave some earlier location, no matter how it
reached such earlier location, by the superior pressure of water.
Water indeed has much to do with what, for lack of a better
t ;3J>-;:::
FUEL AND ITS APPARATUS
term, may be called the hydrogeology of petroleum. When a
petroleum well gushes, it does so because the oil is being pressed
upon by water, which, but for the presence of oil, would itself
rise near to or above the surface.
A case may be pictured, as in Fig 0, where a porous stratum m
is fed with water from the surface at 8. This water escapes
by some opening to the surface, or it may flow away in the
direction of c to some surface spring at the level of the water
line marked W.L.I.
In the anticlinal fold or dome under the point A there would
be a reservoir of oil under a water pressure equal to P. A bore-
hole at A, right above the ridge of this buried anticline, would
W.L
WL 2
W.L 3
Fig. 0. HYPOTHETICAL SECTION OF OIL-BEARING STRATIFICATION.
allow this pool of oil to escape at the surface as a gusher.
And when all the oil had escaped the well would yield water.
Similarly a boring at E would yield oil equally freely, but
water would follow while still the crown of the dome contained
oil above the upper dotted line. A well at G would yield
water from the first, while at D neither oil nor water would be
found unless the bore-hole was carried down below W.L.I.
Let all the conditions remain the same, except that the water
level stands at the line W.L. 2. The same results would happen,
except that the wells would not yield above the surface. They
would be known as pumping or baling wells. The hole D
would pass through the water-bearing stratum on to the left of
the water level, and would therefore be dry. It is easy to
multiply these assumed geological forms in order to account for
every peculiarity that may be met with.
Readers can picture for themselves the very much wider
fields over which boring would be successful if the water only
THE GEOLOGY OF PETROLEUM 31
stood at W.L.3, for with suitable stratification to the right of
c, it would be possible for oil to fill the stratum m even to the
surface, and the whole of the oil could be finally baled, and
without meeting with water. Nor is it necessary to assume the
existence of a buried anticlinal. A mere frustrum may alone
have been left by surface denudation and borings along the
side slopes of this frustrum may reach oil. But a gushing well
demands artesian pressure or gas as its acting force.
The boring of an oil well is complicated by the occurrence
of water-bearing strata above the oil-bearing stratum, and it
is possible to let down this upper water into the oil stratum
below in such a way as to force away the oil and render
large areas barren of oil. Hence the extreme importance of
shutting out such water by casing tubes tightly inserted.
Thus if n was a water-bearing stratum the casing pipe must
pass through this and enter well into an impermeable stratum
below, such as let it be supposed i may be.
Where the slopes of an anticline are steeply inclined the oil
fields will be very narrow, and this explains the closely spaced
derricks seen on some fields extended in a narrow line along
the anticlinal ridge. Every bore-hole that is put down affords
figures from which the underground contour of the rocks can
gradually be worked up, and plots of land gain or lose in value
as it becomes easier to make definite statements as to the depth
to the oil stratum and the certainty of being to the left or right
of points, such as e, on which yield depends. An inspection
of Fig. 1 will serve to show how easy it may be to drive casing
so as to shut off a supply of oil, and how it might also happen
that instead of oil, water would be obtained. It is also clear
that a well may cease to yield oil sooner than it would do if the
casing had not been driven too far. Thus a well that has
ceased to yield might, on occasion, be again brought in by
perforating the casing at a suitable horizon.
Any attempt to prove oil or find it without some surface
indication is considered to be speculative or of a " wild cat "
order. But there can be very little doubt that great deposits
of oil are lying hidden beneath rocks which are completely
shut down below superincumbent strata and have no outlet
to the surface by which they can give the faintest indication
of their presence. Oil exploitation so far has been carried out
on the lines of working coal seams from their outcrop only.
Coal is a regular geological stratum, and its presence may be
inferred at long distances from any outcrop, as it was inferred
at Dover as a result of the artesian boring in Tottenham Court
Road. But oil is not a geological positive fact, for it may be
32 LIQUID FUEL AND ITS APPARATUS
found to-day far from its point of formation, as stated above,
having suffered lateral or vertical transfer by the agencies of
heat, water, gas or gravity. It is therefore liable to be found
in strata of all geological periods. If present in Great Britain in
serious quantity it is probable that it will only be found at very
great depths. Very little is known of the deep-seated rocks
of Britain below the coal measures, and the deepest coal mine
is not much over half a mile. But the recent strata of the south-
east of England are now known to He unexpectedly and uncon-
f ormably upon ancient rocks of Devonian and Silurian and also
Carboniferous age. So that the unexpected may yet happen
in the shape of a petroleum field in Great Britain, possibly
in the deep-seated Old Red Series which are known to yield
salt water and suspectedly petroliferous.
Petroleum Drilling and Pumping
Oil wells are bored by the aid of a derrick about 50 to 80
feet in height ; 72 feet being a very usual height. A derrick is
built up of four stout inclined corner posts, braced by horizon-
tal struts and diagonals. Many modern derricks are of steel.
The tool usually employed is a heavy chisel attached to a
heavy sinker bar. Sinker bars vary in size from 2J inches
square by 30 feet long up to 7" x 15 feet. They are raised and
lowered, by a rope or by a line of iron rods or poles. A rapid
up and down stroke is given by means of a walking beam to
which the rope or rods are attached by a long screw frame or
temper screw, or by a chain from a winch carried on the beam
itself. The rope is let out by turning the temper screw as the
chisel cuts the rock and the rods are lowered gradually by the
winch. Debris is removed by drawing up the line of tools and
lowering the sand pump or shell, a long tube with a valve at
its foot, by means of a winch and rope over a pulley at the
top of the derrick. The walking beam and the winch barrel
are set in motion by means of belts from pulleys on shafts
driven by an engine, such belts being slack, but tightened up
to working tension by pressure from lever-actuated jockey
pulleys. Other levers control the band brakes which hold the
mechanism securely at rest when needed. A second winch
raises and lowers the casing tubes. In Russia wells may start
with casing as big as 24 or 36 inches diameter. In America
wells are usually 8 and 10 inches, finishing as small as 4 inches.
Another system of boring is the rotary system, by which the
casing itself forms the tool and is rotated by gearing at the
THE GEOLOGY OF PETROLEUM 33
surface and sinks through loose strata by the aid of a flush of
water forced down the casing, and escaping into the strata
through which the casing penetrates, or making its way to the
surface outside the pipe.
Boring operations are simple while things go well, but ropes
and rods break, the bore-hole walls fall in, the chisel is jammed
fast or the casing collapses under heavy pressure from without,
and a great variety of salvage or fishing tools are made to combat
these contingencies. Hence the need for strength and the
reliability given by Low-moor or Farnley iron for special items.
Owing to the inflammability of the gas and oil which a well
may yield, the boiler is kept well back from the derrick, and the
engine is connected by a long belt to the mechanism of the rig.
Derricks are now frequently formed entirely of steel.
Casing consists of lengths of steel pipe screwed to a butt
joint and socketed. They are used in random lengths, unlike
the English artesian system of using dead lengths of 10 or 12
feet, which render it so much easier to know the exact depths
to which casing has been driven.
When oil has been obtained, but does not flow to the surface,
it is raised by the baler, a long pipe with a valve at its base,
which is lowered by a winch and rope into the oil and hauled
up full of oil. Baling may be continuous night and day at maxi-
mum possible yield, or, if supplies are poor, baling will be done
morning and evening for as long as desirable, the oil accumulat-
ing in the day and night between baling times.
Or pumps may be employed, and on some fields many pumps
are worked from one central engine by means of a crank rotat-
ing on a vertical spindle and hauling upon a number of tension
ropes attached to the pumps like spokes radiating from a central
hub. When the oil is not too deep below surface the air lift
pump may be employed, though this is expensive to work, owing
to the general low efficiency of compressed air, but it has some
very serious advantages.
Given that the oil is present in a well, more can be raised by
the air lift in a given time than by any other system. This is
specially valuable where there is a free supply of oil and the
well is of small diameter.
There are no moving parts down the well. Any number of
wells can be pumped from a single power station, the compressed
air being carried to each well by a branch from an air main.
The central power station may be at any distance from the
wells, so avoiding all risk of fire.
Oil containing sand can be raised with ease. Sand causes a
good deal of wear in pumps. Both pumps and balers can be
c
34 LIQUID FUEL AND ITS APPARATUS
worked with safety by enclosed electric motors, the current
being brought from a safely distant power-generating station.
In using boring systems which involve the employment of
water flushing for debris removal, there is risk in some circum-
stances that the oil when reached may be driven away by the
water flush and passed by without its presence being suspected.
Engineers should always be alive to this danger.
Diamond rotary drilling is not employed for oil drilling, for
the " crowns " become two expensive for the size of holes
required to be drilled.
Hard rocks may be easily penetrated by the rotary process
with chilled steel shot. But this system requires a flush of
water with its possible disadvantages. The ordinary method
with heavy crushing chisel has the very serious disadvantage
that it smashes everything to a pulp, and destroys the best of
the fossil evidences of the rocks passed through.
CHAPTER II
THE ECONOMIES OF LIQUID FUEL
IN considering the application of liquid fuel every case
must be taken by itself and the costs evaluated. In
favour of oil there is, first, the ease and rapidity with which
a liquid can be taken into store and delivered to the bunkers
of a ship or the tank of a locomotive. Next there is the
economy of labour^ which may be almost nil in case of a single
boiler with one attendant to the engine and boiler, or it may
be very great where there are many boilers.
The superior calorific power of oil must then be equated
with the price, and the cost per unit of evaporation found from
this.
The removal of cinders and ash may or may not be a matter
of cost, according to the demand for them locally.
Liquid fuel possesses great elasticity of use and fits well
with sudden and varied demands for power. Hence its value
in railroad work, electric light work, and other power stations
where loads vary greatly.
Where the mixed system is employed, as with the Great
Eastern Railway, the mere question of economy, as based on
the actual weight of fuel consumed, is to be found as follows :
A locomotive consumes N units of coal per unit distance.
When running with coal and oil, it is found to consume
M units of coal.
oil.
The price of coal is y ; of oil x per unit.
Then O x M x N x - or , L -*-
The cost of oil is largely a matter of carriage. What costs
three francs = 2s. 6d. per ton at Baku costs 185 francs =
7 8s. 6d. in France. The difference of 182 francs is made up
of railway and sea carriage, handling, customs, warehousing.
The customs stand for ninety francs, so that the same oil at
an English port should not cost over 3 16s.
35
36 LIQUID FUEL AND ITS APPARATUS
American residues cost five to six francs more than Russian
mazut, whence MM. Colonner and Lordier, who give the above
figures, dismiss oil as an economical fuel in France pending the
reduction of the tariff.
On the Southern Pacific Railroad the relative evapora-
tion of oil and coal is 365 : 274, or 33 per cent, in favour of
oil.
On the International and Great Northern four barrels of oil
proved more than equal to a ton of coal, and at 12s. 6d. per
ton and 2s. 4d. per barrel the economy of oil was 13 to 14 per
cent., including the economy of handling and storing.
To produce 1,000 units of steam, coal gives out more carbonic
acid than oil, though the oil destroys quite as much oxygen
and reduces the life-supporting power of the air to probably
equal extent. So long as combustion is perfect and no actual
poisons are made, there is not much to choose between the
two fuels beyond their sulphur contents. As regards the
safety of oil, it has been shown that oil with 117C. = 239F.
flash-point did not ignite if fired at with shell, nor did
dynamite exploded in a reservoir of this oil do more than throw
up jets of oil which did not ignite.
Any danger with liquid fuels is with the oils which have not
parted with their inflammable and volatile gases. This is a
danger with oils when used absolutely crude. Purged of
these portions, however, oil is safe, and, moreover, unlike coal,
it contains no power of spontaneous combustion. Though
it is claimed by some that oil does not deteriorate if kept in
tanks, others do claim that a certain deterioration is produced
which renders it difficult to atomize, the oil becoming more
thick and viscid.
In Russia circular atomizers are often employed which give
out a large hollow flame. The Bereznef atomizer, is one of
these. They have the disadvantage of being out of reach in
the middle of the fire of a locomotive, and they become burned
also through being in such close contact with the flame.
Steam enters below a central disc, and oil flows under a
head of two to three metres on the upper side of the disc.
The advantage of this form is said to be its constant out-
put.
Too much mazut produces smoke, too much steam is waste-
ful. There is a certain fixed ratio of oil and steam to give the
best result. The Issai'ef atomizer, which resembles the Berez-
nef, will feed 50 to 100 kilos, of oil per hour (110 to 220 lb.),
and it consumes nearly 0-4 kilos. 88 lb. of steam at 4 to 5
atmospheres pressure per kilo, of oil (2-2 lb.). The table,
THE ECONOMIES OF LIQUID FUEL
37
DATA.
NO. OF TEST.
1
3 atomizers
Beieznef
2
4 atomizers
Kroupka
3
1 atomizer
Bereznef
4
3 atomizers
Bereznef
5
3 atomizers
Baschinino
Duration of trial. Hours .
Total kilos, of oil consumed.
Mean boiler pressures in at-
mospheres
12hrs.
2193k.
4-5
41C.
31,096
29,140
14-17
13-28
0-987
13-1
120C.
132C.
27C.
185
lOh 30m.
795-7
5-0
38C.
11,912
11,122
149
139
1-131
15-81
85
130 3
27
0422
60
lOh 30.li.
1,104
4-5
46 6C.
16,232
15,071
14-7
1365
1-569
21-42
87-3
139-1
20
0-364
60
7 hrs.
1,183
5-0
19 2C.
16,284
15,805
13-76
13-36
1-469
19-633
68-9
90
27
115
9 hrs.
1,183
4-75
20-2C.
16,832
16,310
14-22
13-78
1-143
15-758
64-6
80
26-8
115
Mean temperature of feed
water
Litres of water fed to boilers
Kilograms of water fed to
boilers .
Kilograms of steam produced
at feed temperature per
kilo of oil ....
Kilograms of steam produced
from 0C. per kilo of oil .
Oil per hour per square metre
of grate surface. Kilos. .
Steam per hour per square
metre of grate surface.
Kilos
Tempera- j* f eed water .
ture 1 of chimney gas .
( of air above boilers
Atomizing steam per kilo of
oil. Kilos
Heating surface. Sq. metres
1 square metre = 10 -76 square feet. Kilograms per square metre
-T- 5= pounds per square foot nearly.
above, is given by M. Keller, of Moscow, as the result of
tests made with various atomizers.
M. Bertin, in dealing with the efficiency of liquid fuels,
points out that a fuel containing 85 per cent, of carbon and
14 per cent, of hydrogen, will consume the oxygen of 7-56
cubic metres of air to satisfy the carbon, and of 2-72 metres to
satisfy the hydrogen, or 10-28 cubic metres in all. By adding
40 per cent, excess of air, or 14-4 cubic metres 18-7 kilos.
of air per kilo, of oil, then combustion will be perfect and
smokeless.
The Author's own figure for the weight of air chemically
necessary for the above sample would be 14' 7 nearly, and 40
per cent, excess would increase this to 20-56. M. Bertin's
figure of 18-7 appears to represent about 27 per cent, air excess.
The theoretical temperature of combustion will be
(18-7
38 LIQUID FUEL AND ITS APPARATUS
If the gases leave the boiler at 300C. 572F. the loss of
heat will be -^ - = 12-10 per cent, of the total, which is equi-
valent to an increased efficiency of 6-65 per cent, as compared
with coal. He further estimates a gain of 1-9 per cent, over
coal in the absence of ashes and their cooling (onboard ships).
The efficiency of a boiler estimted at 75 per cent, for coal,
becomes 0-835 for oil firing, or 0-75 + 0-0665 + 0-019
0-835.
But good combustion and utilization still further favour oil
835
in the ratio 1-28 m ; m becoming then r = 1-20 x
1-28 = 1-53 ; the figure 1-20 being the chemical ratio of power
of coal and oil. In Torpedo-boat No. 62 (French) M. Bertin,
however, only obtained m I'll and r = 1-33. The causes
of the difference are found in the nature of the flame of oil,
which has less radiating power than the flame of coal, and the
powerful effect of the directly heated coal furnace is sacrificed,
and to secure the same results an undesirable extension of heat-
ing surface would be necessary.
Secondly, the flame of oil is long if care be not taken suitably
to arrange the burners. It may pass between the tubes and
become extinguished, and the gases partly burned may even
relight in the chimney. The chemical action and reactions of a
burning spray of oil may be very much complicated by disso-
ciation or even by exothermic formations, which may delay
heat production. Later when combustion becomes active as
shown by the light giving power of the flames, it will be more or
less rapid according to the perfection of air admixture, and will
last for a time = t, during which the jet, travelling at a high
velocity, v, passes through a distance L = vt, which may be
yards in length.
Thus the course of the gas must be long, or it may escape too
hot to the chimney. Hence arises the necessity of cutting short
the flame by early admixture and high temperature, so as not
to lose the benefit of the boiler-heating surface.
It is for this purpose that in most successful oil-burning fur-
naces the jet of atomized oil is directed upon a brick obstruction
of some kind so as to spread the flames and cause them to fill
the furnace space and lick round the plate surface. Locomotive
fireboxes may be studied, as in Fig. 26 to show how this effect is
secured before the gases escape to the small tubes.
General Prinicples of Liquid Combustion. A review of the
THE ECONOMIES OF LIQUID FUEL 39
whole subject, in the light of chemical knowledge, of the claims
of manufacturers and of users of liquid fuel, shows that success-
fully to burn a liquid it must be finely pulverized, to do which
it must be heated sufficiently to destroy its viscosity and en-
able the spraying agent, air or steam, to tear it up and disperse
it in a fine spray intimately mixed with air. The correct
amount of air must be admitted to burn the liquid, and this is
one of the advantages of employing air as the atomizing agent.
Where sufficient air cannot be introduced with the fuel, it
must be admitted from below, as through grate bars covered with
broken bricks. Steam, preferably superheated, is the most
convenient to employ as the atomizing agent, but on the salt
seas has the disadvantage of wasting from 3 to 5 per cent,
of the steam made by the boilers, and this loss must be made
good by evaporators.
As with bituminous coal, which, like oil, is a complex
hydrocarbon, liquid fuel should be burned in furnaces more
or less protected from immediate loss of heat to the boiler
surfaces by means of linings or baffles of firebrick. Liquid
fuel, however, is more easy to burn completely than is coal,
because it can be more intimately mixed with the necessary
air. The interior of a combustion chamber should show a
clear white incandescence with little apparent flame, and no
smoke or unburned gases coming from the chimney. If looked
into through a piece of violet-coloured glass, the interior of the
combustion chamber with its brick linings should show a light
lavender colour indicative of perfect combustion, with the pro-
duction of actinic rays indicative of high chemical action. A
chilled fire, such as is produced where a boiler is placed close
upon the furnace of a coal fire, will show very little light indeed
through a violet glass, its flames being cut down from several
feet in length to a few inches only in many instances, the flames
of yellow and reddish intensity being resolved into streams of
dun-coloured gas which throw off no light of sufficient actinic
power to penetrate the glass.
Much difference of opinion exists in regard to the flash-point
of the oil to be used. Crude oil is so widely different a product,
according as it comes from one or another locality, that no rule
can be laid down as to its safety or otherwise. Those crude
oils which, like the Pennsylvania oil, give a large proportion
of gasolene and other volatile compounds, are not used in their
crude form because they pay better to refine, the heavier resi-
duum being used as fuel and being much safer. The use of
volatile liquids is only undesirable on the score of safety.
Some of the crude oils, as for example those of the Beaumont
40 LIQUID KIEL ANt> ITS APPABATtTS
field of Texas, contain so little of the lighter oils that they are
used as fuel in their crude form. The one thing to note is that
the more highly volatile oils have an element of danger from
which the heavy oils are free, and this danger intensifies the
results of every possible accident that may occur, especially such
as arise from rupture of an overhead tank and the gravitation
of the oil to lower points. The whole question is really very
simple, and resolves itself into an intimate mixture with air in
sufficient quantity and a proper conservation of the temperature
pending full combustion. Fortunately for liquid fuels, these
items are not only easy to realize, but failure, when they are
not realized, is far more disastrous and complete than in the
case of solid fuels. Hence the really simple problem of burning
bituminous coal has never been properly solved, except in a few
cases. At the same time it is easy of solution, but if not solved
it does not produce the same bad effects as does the faulty com-
bustion of liquid fuel. In regard to this question, the Author
would like to point out that, where coal is burned in a refractory
furnace, it should be capable of burning perfectly, with less
excess of air, and coal ought to give results more nearly ap-
proaching its true value than it does do in ordinary faulty
daily practice. Probably all the comparisons given in this
book, except, perhaps to some extent those of locomotives,
are too favourable to liquid fuel, which is supplied with those
essentials of perfect combustion that are withheld from coal.
This question of refractory linings is essential, and it is
secured by bridge walls, overarching and, where fire-bars are
left in place, by covering these with broken firebrick or by whole
bricks laid on edge.
It does not seem possible to introduce all the necessary air
with the fuel. A chemical minimum of fifteen pounds of air-
is necessary to supply the oxygen for the average hydrocarbon
liquids, but probably at least 5 to 10 per cent, excess is required
in the best practice, and this must come in below the oil spray,
and should not be introduced in a single large stream, but
divided up into numerous fine streams through perforated plates,
or through a mass of broken bricks or loosely laid brickwork.
In Fig. 51 is shown the arrangements of air admission at the
floor of a water- tube boiler furnace which is in the right direc-
tion. The Weir boiler, Fig. 7, p. 121 is also suitably arranged
for liquid fuel, as regards the lining of the furnace and combus-
tion-chamber. Where liquid fuel is used alone the fire-grate
would be covered with bricks laid on edge or simply broken into
pieces of 2-inch cubes, and the atomizers would be arranged
similarly to those of Fig. 51. The general conditions that have
THE ECONOMIES OF LIQUID FUEL 41
been evolved are well shown in the various locomotive and
stationary boiler furnaces illustrated in Part II.
In the Weir small water- tube boiler the sides of the y\ -shape
furnace are lined in firebrick blocks which are threaded upon
the middle widely spaced tubes which form the walls of the
furnace proper.
The first row of the main body of tubes is similarly protected
to form a refractory wall for the combustion chamber. Thus
both the furnace and combustion-chamber are fully refractory
on two sides. Such a boiler as this can be worked with coal
entirely, with oil alone, or upon the mixed system, the brick
linings enabling combustion to be carried out with smokeless
and economical perfection.
s By means of sight-holes the furnace can be examined, and the
admission of air gradually increased until the gases become
clear, clean, brightly incandescent red, and the opposite end of
the furnace shows up clearly. So long as there is smoke-forma-
tion the opposite brickwork cannot be seen. As soon as com-
bustion is perfect it appears clear and bright red, and the air
should then be cut down in quantity until an occasional streak
of dark-coloured gas begins to show, thus proving that under
the conditions of the furnace the air has been reduced to a
possible minimum.
Under some conditions of boilers it would appear that to
ensure smokeless combustion of liquid fuel, not more than 2 to
3 Ib. should be consumed per hour per cubic foot of combustion
space. This will have considerable bearing upon the question of
furnaces with or without fire-grates, the latter type more easily
securing the requisite volume. The above figure may be borne
in mind when considering the question of furnace dimensions.
More recent practice is claimed to give a nearly smokeless com-
bustion with a rate of 20 Ib. of oil per cubic foot per hour.
The term liquid fuel is herein limited to
1. Coal gas tar, creosote, coke oven tars, blast furnace tars,
and the tar from oil gas manufacture and other pro-
ducts of the destructive distillation of fuels, including
the more volatile naphthas.
2. Petroleum and other mineral oils found liquid in nature or
distilled from bituminous shales.
In a work of this nature, also, it would not be possible to
take notice of all the uses of liquid fuels. For the purposes
of this book, therefore, liquid fuel includes the products under
sections 1 and 2 which do not possess a volatility or refinement
greater than those of the heavy paraffin series or lighting oils.
/ The crude mineral oils of course contain such volatile consti-
42 LIQUID FUEL AND ITS APPARATUS
tuents, and may be used in their crude form, but usually the
superior value of the distillates leads to these being first sepa-
ated, the coarse residuum known as astatki or mazut being the
oil so much used as fuel. Having been deprived of its more
volatile portions, it is safer to carry and to use.
A liquid will not burn when cold, and cannot be ignited in
mass. If heated to the point of ebullition and supplied with
air, it will of course burn fiercely and uncontrollably. The
art of burning liquid fuel consists in heating only the portion
which is to be immediately burned and exposing it to contact
with air. Unlike coal, it is not possible to burn it at many sur-
faces. A coal fire is made up of many pieces of coal, each burn-
ing over its whole surface. / Liquid fuel will not lie on a grate in
separate pieces. If, however, a layer of liquid were heated to
vaporizing point, or nearly so, on a finely perforated plate,
and highly heated air were forced through the perforations, the
liquid would no doubt burn freely with strong flame, but the
mass of heated liquid would be difficult to control. Hence in
practice we arrive at those systems which employ a jet of air or
steam to split up a stream of liquid into fine globules in presence
of a sufficient supply to air. Each globule burns superficially
and becomes heated by its own combustion and the general
heat of the furnace, and this principle appears to be the best
and most effective method of burning liquids. Indeed, it is
perhaps the best method of burning anything, first to reduce
it into particles so fine that their bulk bears a small ratio to
their surface area, whereby each particle is brought close to the
air which it requires.
Atomizing.
The necessity for atomizing arises purely from the insufficient
surface area of the fuel otherwise treated. A fire composed of
lumps of coal is full of interstices, and the area of the fuel ex-
posed to air is much greater than the area of the fire-grate.
Liquid fuel would fall through the grate. It cannot be burned
on a flat surface, because, being liquid, it tends to flow together
and presents only an upper surface to the air. The use of
trough-shaped bars along which the liquid flows and through
which streams of air are admitted, does not get over the diffi-
culty of small exposure of surface.
There is no incandescent mass through which air is flowing
to carry off the fuel in a burned state and to maintain the mass
incandescent. If the whole of the liquid mass in a furnace did
become incandescent, or even approached that point, it would
THE ECONOMIES OF LIQUID FUEL 43
distil in the form of vapour, and, if provided with air, would burn
away uncontrollably, probably with great evolution of smoke.
The more easily combustible or volatile portions would dis-
appear first and the remainder would probably be left over un-
consumed. Thus if the fire is to be controllable, the fuel must
be supplied as it is consumed, so that at no time is there any
serious amount of burning fuel in the furnace, and the produc-
tion of steam is at once regulated by a simple regulation of the
fuel supply. This end is secured by atomizing the fuel and
discharging it into the furnace mixed with air, so that each
atom of fuel is in contact with air, and combustion is easily
effected. It will be found that with all the heavy liquid fuels
atomizing is essential.
+
Vaporizing.
With lighter oil, as the cheap lamp oils used in steam motor
cars, the liquid is supplied through a coil of pipe heated by the
flame itself and is converted into vapour, which burns freely
when mixed with air. With this oil it is not found that a
deposit of carbon takes place in the retort coil, as might be the
case with heavier oils. The lighter oils already prepared by
distillation at a moderate temperature can thus be burned with-
out atomizing, but, after all, their resolution into the form of
vapour may be taken as the most complete form of atomization,
and atomization is really a substitute for vaporization.
Varieties of Liquid Fuel.
In nature liquid hydrocarbon is found both free and absorbed.
The free liquid is obtained from bore-holes put down to the oil-
bearing stratum. When not free it is obtained by distillation
from bituminous shales. The latter have been more employed
for lighting or illuminating and lubricating purposes. The
free oil or petroleum has forced its way into consideration as a
fuel, having been employed now for many years in Russia.
In addition to the natural oils, there are many hydrocarbons
formed in the arts which have a high value as fuel. Of these
there is the tar of the gas-works, a black viscous liquid which
separates out from the gas in the process of cooling. It is
formed in the hydraulic main and in the pipe coolers and con-
densers. A thinner tar is produced in the condenser of oil-gas
plant as a product of the destructive distillation of oil in the
Pintsch gas process. Where blast furnaces are fed with coal
in place of coke, tar is produced in the condenser pipes of the
44 LIQUID FUEL AND ITS APPARATUS
residuals plant, and in modern coke ovens a tar is also produced
from the gas driven off the coal.
Crude petroleum contains many hydrocarbon compounds
varying from the formula CH 4 up to Cu, H 37 , the general
formulae being C n H 2n and C n H 2n+2 in an isomeric series of
many numbers. When subject to distillation some of the
compounds are split up, and certain compounds have been
found to contain as much as 95 per cent, of carbon.
American Petroleum Fuels.
In the United States the oils principally sold for fuel pur-
poses are the by-products of crude oil ; their gravity varies
from 23 Baume to about 34.
The oils of lower gravity are known usually under the name
of Reduced Fuel Oil, and one of gravity 23 was found to analyse
as follows
Carbon 87-72
Hydrogen 11-45
Weight per gallon 7-62 pounds
Weight per imperial gallon 9-14
B.Th.U. per pound 19,800
Calories, per kilo 11,000
The oils of higher gravity are known as Distillate Fuel Oil,
and one at the extreme end of the scale, or 34 Baume, analysed
as follows
Carbon. . 86-19
Hydrogen 12-51
Weight per gallon (American) .... 7-11 pounds
Weight per imperial gallon 8-53 ,,
B.Th.U. per pound 20,250
Calories per kilo 11,250
Oil being sold by the gallon an oil of 23 gravity contains
151,066 B.Th.U., and one of gravity 34 contains 143,988
B.Th.U. per U.S. gallon. (8J Ib. of water).
The heavier oil possesses the greater calorific capacity per
gallon. It would be better practice to sell oil by weight or to
state calorific capacities per gallon. For marine work the best
oil contains the greatest heat-producing capacity per unit of
volume, for this implies so much more efficiency of bunker
capacity.
Approximately the two extreme oils named contain per
imperial gallon (of 10 Ib. water)
Gravity 23B = 181,340 B.Th.U.
34B = 172,870 B.Th.U.
THE ECONOMIES OF LIQUID FUEL 45
An average oil measures about one million B.Th.U. per cubic
foot, or 35,000,000 units per 35 cubic feet of space. A ton of
coal which occupies about 35 cubic feet contains about 33,000,000
units of heat. In heat capacity, oil has the advantage over
coal, apart from the fact that oil can be stored in small ballast
tanks, and the coal bunker capacity of a ship can then be used
for paying cargo. /
Texas and California Oils.
These oils are used as they are found, that is to say, princi-
pally in crude form.
Determinations have been made of the calorific effect of these,
and two are subjoined
B.Th.U.
Calories.
Lucas Well- Jefferson Co
Higgins Oil & Fuel Co. Jefferson Co. .
19,574
19,785
10,874
10,992
Texas oil is high in sulphur, containing this to the extent of
2 per cent. It is said that no injurious effects are produced upon
fire-boxes or boiler-plates generally, and it appears rational
that this should be so. The furnace products never pass away
except at a temperature above that of saturated steam, and
it appears unlikely that the dry hot furnace gases should con-
dense to moisture on the boiler-plates, especially of highly
heated high pressure boilers. Care is of course always neces-
sary that furnace gases shall not make contact with any surface
water cooled below 100 F. 38C. Otherwise corrosion may
occur. Dry sulphur oxides, however, seem to be innocuous.
The Tables I, II, III, and IV are given by Sir Boverton
Redwood, whose works may be consulted in all that relates to
the chemistry of petroleum, which is too wide a subject fully to
be dealt with here.
Six thousand heat units are, states Dr. Engler, rendered
latent in liquefying carbon, but this appears doubtful, for the
conversion of solid carbon into gaseous carbon is not proved
to render latent more than 5,817 B.Th.U. per pound, though
Berthelot states that there may be a further amount, which he
denotes as e. It is improbable that the liquid form of carbon
will absorb so much as 6,000 units. As regards water, tfre
latent heat of liquid is only about one-seventh the latent heat
of vaporization. It is probable that a considerable difference
exists also in the case of carbon. Against this is to be placed
46 LIQUID FUEL AND ITS APPARATUS
the fact that carbon has no intermediate state between solid
and gaseous, but passes directly from one to the other when
burned. It can only be said to be liquid when combined with
other elements.
Russian Petroleum.
Russian oils are the inverse of the American oils, for while
the latter contain about 25 per cent, of residuum, the former
may contain 75 per cent. Astatki or residuum varies from
35 to 60 per cent, of the crude oil, and is really the chief product
of the Russian oils.
The specific gravity of crude petroleum varies from 0-771 to
1-020, and the following general values are given by Sir Boverton
Redwood.
Sp. Gr.
Crude petroleum (Redwood) .... 0-771 to 1-020
American (Hofer) 0-785 to 0-936
Wyoming ' 0-945
Galician 0-799 to 0-902
Baku 0-854 to 0-899
Canada 0-859 to 0-877
The percentage of residue in various oils is given as follows
Pennsylvania 5 to 10%
Galician 30 to 40%
Roumanian 25 to 35%
Alsace 35 to 60%
Baku 36 to 60%
The composition of oils is thus very varied.
Creosote Oils.
Properly speaking, creosote is that distillate from coal tar
which is intermediate between crude naphtha and pitch.
It is sometimes called dead oil and heavy oil, because its
specific gravity is greater than unity.
In a wider sense creosote oil is understood to include the
heavier oils from bituminous shales as well as the liquid de-
posited from coke oven and blast furnace gases. These various
oils are all combustible, and though by no means properly
called creosote, the distinction is not of importance as regards
their value as fuel.
True creosote is probably too valuable as an antiseptic in
wood preservation to allow of its very extensive use as fuel.
Coal tar creosote consists of that part of the tar which distils
between 200C. and 300C., and includes various naphthalene
bodies, etc. In colour it is yellow green and fluorescent. Its
specific gravity is 1*10 to 1-024, according to quality, the
THE ECONOMIES OF LIQUID FUEL
47
London made oils being heavier than provincial oils, simply
because London is supplied largely with Newcastle coal, while
country oils are from Midland coals of different quality.
As regards the constituents of creosote, the chief are naphtha-
lene, carbolic acid and cresylic acid, and the composition of
these bodies is as follows
Creosote.
Constituent.
Formula.
Percentage composition.
Carbon.
Hydrogen.
Sp. Gr.
Melting
Point.
Naphthalene
Carbolic acid
Cresylic acid
GIO^S
C 6 H 6
C 7 H 8
93-75
76-5
77-78
6-25
6-3
7-4
0-978
1-056
1-04
79C.
42C.
33C.
The foregoing is a very brief summary of the properties oi
creosote oils. Full information is to be found as regards the
chemistry of the coal tar compounds, in vol. ii. of Allen's
Commercial Organic Analysis. The above will serve to show
that these tar products are largely combustible, and may be
burned in the same way and with the same apparatus as used
for petroleum.
The fuel oil of the Anglo-American Co. is crude oil deprived
of its more volatile constituents. Its specific gravity is 0-893
to 0-910 at 60F., and the closed test flash point is 220 to
250C.,and the calorific value 19,000 to 19,800 B.Th.U. per Ib.
Blast furnace oil has a specific gravity of 0-988 ; shale oil
creosote is similar. Coal tar from gas works has a specific
gravity of 140 to 1-20, and is very complex in composition.
London tar contains from 2-5 to 8 per cent, of ammoniacal
liquor, 0'5 to 3-4 per cent, of light oils, 17 to 23 per cent, of
creosote and carbolic oils, 13 to 17 per cent, of anthracene oils,
and 58 to 62 per cent, of pitch.
The distillates from coal, bituminous shale and wood all
contain more or less oxygenated bodies. Coal and shale dis-
tillates contain some nitrogenized bodies. Petroleum, on the
other hand, contains only hydrocarbons.
Shale tar has a specific gravity of 0-865 to 0-894 according to
the method of retorting practised. It consists of a complex
mixture of hydrocarbons of the paraffin order C n H 2n+2 ; of
the olefin order C n H 2n , and of hydrocarbons C n H 2n _ 2 with
some oxygenated bodies.
About thirty gallons of oil can be distilled from each ton of
shale.
CHAPTER III
THE CHEMISTRY OF TEXAS PETROLEUM
IN Bulletin No. 4 the Chemical Laboratory of the University
of Texas, Dr. E. Everhart gave the results of an examin-
ation of the Nacogdoches oil, the analysis having been made
by Mr. P. H. Fitzhugh. The report says
" The oil has a brownish-red colour. The odour is peculiar,
but not so offensive as the crude petroleum of Pennsylvania.
At ordinary temperature the oil is mobile, but not so much so
as ordinary petroleum. Submitted to extreme cold, the oil
still retains its liquidity, but becomes less mobile. The tempera-
ture of the oil was reduced to less than zero (Fahrenheit)
without it losing its flowing qualities.
" At no temperature attainable in the laboratory by artificial
means could any solid paraffin be separated. The oil does not
gum on exposure to the air. It is not adapted to the produc-
tion of illuminating oil ; its value consists in its use as a
lubricant.
" About four pounds of oil was subjected to distillation over
the naked flame in a retort connected with proper condensers.
The temperature was carried up to 680F. At intervals of
45 each distillate was removed and its weight determined.
The results of the distillation were as follows
Analysis of Nacogdoches Oil.
Per cent, by weight.
Below 300F 0-04
300 to 345F . . . . 0-37
345 to 390F a 1-38
435 to 480F 3-14
480 to 525F 6-25
525 to 615F . 7-07
615 to 680F 5-63
Remaining in the retort 74-03
" The above figures show that the crude petroleum is practi-
48
THE CHEMISTRY OF TEXAS PETROLEUM 49
cally free from naphtha, which distils off below 250F. Four
pounds of this oil carried to a temperature 50 higher yielded
only a few drops of a light oil, amounting to 0-04 per cent, of
the total amount taken. In the Pennsylvania crude petroleum
the illuminating oil comes off between 250 and 500F., and,
on an average, amounts to about 55 per cent. The Nacog-
doches petroleum between the same degrees of temperature
yields only a little over 7 per cent. Three-fourths of the oil
does not boil until a temperature above the boiling point of
mercury is reached. Above 400F. and even lower the dis-
tillate is not pure white, but is somewhat coloured. This
colour deepens on exposure to the atmosphere. The distillate
exhibits fluorescence.
" The density at 62-6F. is 0-9179. That of Pennsylvania oil
is usually about 0-794 to 0-840. The co-efficient of expansion
is : 02568."
Properties of Petroleum.
W. B. Phillips, Ph.D., of the University of Texas, says
" In weight (specific gravity), taking water as 1,000, it varies
from 650, as in certain oils from Koudako, Russia, to 1,020,
as in the oil from the island of Zante. The range is, however,
for the most part, between 770 and 940. A gallon of crude
petroleum will vary from 6-41 pounds to 7-83 pounds for the
United States gallon, and from 720 to 9 -40 pounds for the
Imperial gallon. Exclusive of the barrel, the 40 gallons, or-
dinarily spoken of as a barrel of oil, will weigh from 269-22
pounds to 328-86 pounds.
"With regard to its flow, crude petroleum may be quite mobile,
as in the light-coloured varieties, or quite viscid, as in the black
varieties. The temperature at which it becomes solid ranges
from 82F., as in oil from Burma, to several degrees below zero.
The flash-point (the lowest temperature at which inflammable
vapours are given off) varies from below zero, in certain oils
from Italy, Sumatra, etc., to 370F. in oils from the Gold Coast,
Africa. The ordinary range of the flash-point, however, does
not show such extreme limits."
For oils whose flash-point lies below 60F. the specific
gravity ranges from 771 to 899, the average being 838. On
the other hand, the oils whose flash-points are above the boiling-
point of water have a range of specific gravity from 921 to 1,000,
the average being 959. It is remarkable that a Roumanian oil
with a flash-point of 24F. should have had a specific gravity
D
50 LIQUID FUEL AND ITS APPARATUS
of 899. As a general rule low specific gravity accompanies a low
flash-point. In none of the examples examined, whose flash
point was above the boiling-point of water, did the specific gravity
fall below 921, the average being 959. There is a close con-
nection between specific gravity and flash-point, for the presence
of lighter oils, which are given off at a low temperature and are
more inflammable, tends to reduce the weight of the oil as
compared with water. This is not always so.
The boiling-point of crude petroleum varies from 180F.
with certain Pennsylvania oils, to 338F. with oil from Hanover,
Germany. The point at which oils become solid varies from
82F. with oil from Burma, to below zero with oil from Italy
and Sumatra.
The content of carbon varies from 79-5 per cent, to 88-7
per cent. ; of hydrogen from 9-6 per cent, to 14-8 per cent. ; of
sulphur from O07 per cent, to above 2-00 per cent., and in rare
cases even above 3-00 per cent. ; of nitrogen from 0-008 per cent.,
to I'lO per cent.
Hydrocarbons of the olefin series occur in nearly all kinds of
petroleum, but are specially characteristic of Russian petroleum
from Baku.
Mabery has shown that the distillate from Beaumont oil
coming over between 266 and 275F., gave hydrocarbons of the
acetylene and benzine series, and the same was true of the
distillate coming over between 311 and 320F. He also found
this oil to contain 2-16 per cent, of sulphur and more than
1-00 per cent, of nitrogen.
There is no hard and fast line of demarcation. The chemical
properties shade into each other, and only a general statement
can be made that the oils from Pennsylvania fall into the
paraffin series and the Russian into the olefin series, while
the Beaumont oil is a third class distinguished by the presence
of members of the acetylene and benzine groups.
Bituminous coal contains much less carbon and hydrogen
and much more oxygen than petroleum. Anthracite coal
has about the same amount of carbon as petroleum, but much
less hydrogen and oxygen.
THE CHEMISTRY OF TEXAS PETROLEUM 51
Mr. E. H. Earnshaw made an analysis of Corsicana oil,
as follows:
Analysis of Petroleum from Corsicana, Texas.
Fractions.
Temperature,
F.
Per cent.
Sp. Gr. at
60F.
By Vol.
By
Weight.
Colourless
A
130-200
200-250
250-300
300-350
350-400
400-450
450-500
500-550
550-600
600-650
650-665
650
650
2-80
5-10
7-60
8-20
9-40
7-40
8-30
6-45
7-75
14-95
17-25
1-30
1-40
2-63
2-24
4-31
6-69
7-44
8-75
7-07
8-09
6-43
7-85
15-43
18-07
1-41
1-63
0-6653
0-7017
0-7302
0-7527
0-7718
0-7920
0-8088
0-8260
0-8404
0-8555
0-8687
0-8972
0-9669
B
c
D
E
F
G
Very faint yellow
H
I
Yellow, J
Deep reddish yellow, K .
Deep red (solid), L, over .
Dark red-brown (solid), M, over
Residue
Total .
97-90
98-04
Mr. Thiele's remarks on the oil were as follows
" The oil is very dark brown and opaque, but thin and fluid
at 60F. The specific gravity at 60F. is 0-8292. The oil is
closely related to the oil from Washington district, Penn., but
contains asphaltum or bodies similar to it.
" Nacogdoches oil is heavy, specific gravity 0*915. The
colour is black, and there is much sulphuretted hydrogen.
" Oil from Saratoga, Hardin county, is heavier, the specific
gravity being 0-995. It is black and rich in asphaltum.
" Oil from Sour Lake, Hardin county, has a specific gravity
of 0-963, and analyses as follows
Analysis of Petroleum from Sour Lake, Hardin County, Texas.
Fractions.
Temperature
F.
Per cent,
by Vol.
Specific
Gravity.
Colour,
etc.
1
2
212-266
0=07
Yellow
3
266-320
0-03
Yellow
4
320- 392
1-59-
0-684
Yellow
5
392-572
19-49
0-840
Yellow ; blue
fluorescence
6
7
572-641
5-15
0-782
Dark yellow
Residue .
71-11
0-978
Black
Total .
97-44
52 LIQUID FUEL AND ITS APPARATUS
In the Journal of the Society of Chemical Industry, vol. xix.,
No. 2, February 28, 1900, Mr. Clifford Richardson has the
following
Corsicana Oil.
Specific gravity, 68F. . . . 0-8457
Baume 35-6 (about)
Flash Ordinary temperature.
Volatile, 212F 10-8 per cent, (naphtha).
Volatile 324F., 7 hours . . . 35-7
Volatile 339F., 5 hours . . . 11-2
Total 57-7
Residue, after heating to 323F., flows readily at 68F.,
appears to contain paraffin. After heating to 399F. residue
has a quick flow at 77F.
Sour Lake Oil.
Specific gravity, 68F. . . . 0-9458
Baume . 18-0
Flash 244F.
Volatile, 212F 22-8 (water with trace of oil)
Volatile, 324F., 7 hours . . . 12-6
Volatile, 399F., 5 hours . . . 14-4
Total 49-8
Residue after heating to 324F. flows readily at 70F. After
heating to 399F. ? residue flows readily at 77F.
The specific gravity of Corsicana petroleum is a little greater
than that from near Dudley, Noble county, Ohio, 0*8457 to
0-8333.
Distilled under ordinary pressure, without particular pre-
cautions to prevent cracking, Mr. Thiele found
Sp. Gr.
Naphtha, 10-8 per cent 0-710
Kerosene, 54-5 per cent. . 0-796
Residue, 34-7 per cent 0-905
Twenty grams of the oil, heated for seven hours in an air
bath at various temperatures in a crystallizing dish 2| inches
in diameter by 1| inches high, left a residue of 43-3 per cent.,
which flowed readily at 77F. The residuum resembles that
from Pennsylvania and Ohio petroleum, and apparently con-
tains paraffin scale. It is to a certain extent asphaltic. The
crude, when distilled under a pressure of 1 inch of mercury,
volatilized 51-2 per cent, at a temperature of 356F., but began
to " crack." Ohio oil did not begin to " crack " until 455F.
THE CHEMISTRY OF TEXAS PETROLEUM 53
at atmospheric pressure ; but the Sour Lake oil broke up at the
same point as did the Corsicana. It is, therefore, a less stable
oil than eastern petroleums.
The Sour Lake oil is a very heavy crude petroleum, 18B,
and corresponds in many respects with some of the heavier
California oils of Summerland and Los Angeles in appearance
and properties. It flashes at a low point for such a heavy
oil, 244F.
Properties of various Petroleums.
The following table is taken from Sadtler's Industrial Organic
Chemistry -
Crude Oil from
Sp. Gr. at
63F.
Began
to boil
at F.
Under
302F.
per cent.
302 to 572
per cent.
Over 581
per cent.
Texas-Corsicana
0-821
176
34-6
40-0
15-8
Pennsylvania
Galicia .
0-818
0-824
180
194
21-0
26-5
38-0
47-0
40-7
26-5
Baku . .
0-859
196
23-0
38-0
39-0
Alsace
0-907
275
33-0
50-0
47-0
Hanover .
0-899
238
32-0
68-0
Dr. W. H. Harper, Professor of Chemistry in the University
of Texas, gives an analysis of a sample of Corsicana oil
Colour, very dark brown, almost black ; opaque except in
thin layers ; greenish fluorescence.
Viscosity, not determined, but the oil very mobile at 32 F.
Sediment, none.
Water, none.
Flash-point, 73F.
Specific gravity at 63-5F., 0-8586, equivalent to 33 Baume.
Calorific Capacity of Petroleum.
The B.Th.U. in petroleum vary from 17,000 to 20,000, one
experiment giving 20,110. The value taken in Texas is
18,500 B.Th.U., or 10,277 calories. The scientific investiga-
tion of the coals, etc., used there, with respect to their heat
units, has not progressed very far ; but if is not thought that,
on the average, the B.Th.U. in the coals will be above 12,600,
if indeed above 10,800, and are taken, for the present, at 11,700.
For the lignites a lower value must be taken, and for the present
this will be 9,900.
Some of the Alabama coals have 13,500 B.Th.U. ; good
54 LIQUID FUEL AND ITS APPARATUS
McAlester coal (Indian Territory) may be taken at the same ;
New Mexico coal at 12,000 ; and lignite at 9,900. On this basis
one barrel of crude petroleum, weighing 320 Ib. net. would be
equivalent to 438 Ib. of Alabama coal, and the same amount
of McAlester coal, 493 Ib. of New Mexico coal, and 598 Ib. of
lignite. A ton, 2,000 Ib., of Alabama coal would then be
equivalent to 4-56 barrels of petroleum ; a ton of McAlester
coal to 4-56 barrels ; a ton of New Mexico coal to 4-06 barrels ;
and a ton of lignite to 3-34 barrels. In other words, from
3J to 4J barrels contain as many heat units as a ton of the best
coals and lignites of American Southern States.
Experiments made in California with a view to testing the
relative value of the California oil and the coal with which it
comes into competition, showed that a ton of Nanaimo coal,
giving 12,031 B.Th.U., was equivalent to a minimum oil
consumption of 3*45 barrels and a maximum consumption of
3-87 barrels. Experiments on Texas petroleum showed it to
have 19,160 heat units, and this would be equivalent to 4*29
barrels per ton of Indian Territory coal. In Russia the usual
equivalent is 312 barrels per ton of coal.
There is considerable variation in the quality of coal, and
these differences are often observable in coal from the mine,
due, perhaps, to carelessness in mining and handling, and to the
absence of rigid inspection. In countries where coal is sold
on the basis of heat units these discrepancies are less. Varia-
tions in the quality of oil from the same well are by no means
so marked as in the case of coal from the same mine. The
practice of piping different oil into the same storage tanks
tends to advance uniformity.
The value of oil as compared with coal varies with the nature
of the work to be done. It has been observed that in puddling
and steel-heating furnaces 2| barrels of Los Angeles oil were
equivalent to 2,000 pounds of Wellington coal from British
Columbia, while for steaming purposes it took three barrels of
the oil for one ton of the coal. In some establishments in Los
Angeles the proportion rose to 3-62 barrels per ton ; in others,
to 3-10. On the Southern Pacific Railway it has been found
that four barrels of California oil were equivalent to one ton
of Nanaimo, British Columbia, coal. The lowest consumption of
oil per ton of coal that has been found is 2J barrels, while the
highest is 4 barrels, t In a general way, from 3| to 4 barrels of oil
should be equivalent to a ton (2,000 pounds) of good soft coal.
The lower figures may be reduced under good practice and
management and the best appliances to 3 J barrels ; while under
bad management, etc., the higher figure may reach 4J barrels. /
THE CHEMISTRY OF TEXAS PETROLEUM 55
Advantages of Liquid Fuels.
The advantages to be derived from the use of liquid fuel are
1. Diminished loss of heat up the funnel (or chimney), owing
to the clean condition in which the boiler tubes can be kept,
and to the smaller amount of air which has to pass through the
combustion-chamber for a given fuel consumption.
2. A more equal distribution of heat in the combustion-
chamber, as the doors do not have to be opened, and a higher
efficiency is obtained ; unequal strains on the boiler tubes, etc.,
due to undue heating, are also avoided.
3. No danger of having dirty fires on a hard run.
4. A reduction in the cost of handling fuel.
5. No firing tools or grate-bars are necessary ; consequently
the furnace lining, brickwork, etc., last longer.
6. Absence of dust, ashes and clinkers.
' 7. Petroleum does not deteriorate on storing, while coal does,
especially soft coal. This opinion is not universal, however.
8. Ease with which the fire can be regulated from a low to a
most intense heat in a short time.
9. Lessening of the amount of manual labour in stoking.
10. Great increase of steaming capacity, the difference being
as much as 35 per cent, in favour of oil.
11. The absence of sulphur or other impurities, and longer
life to plates, etc. ; but considering the fact that the amount
of sulphur in some of the oils now being used as fuel is in excess
of the sulphur in ordinary coals, this point is not well taken.
Sulphur is objectionable in any fuel, whether coal or oil, and
of the two may be more objectionable in oil than in coal, for a
portion of the sulphur in coal remains in the ashes, and is not
consumed.
If crude petroleum, or the residue from refining plants, is to
come into use on a large scale as fuel, there are some consider-
ations that must be weighed, in addition to its fuel value, viz.,
its initial price, f.o.b. tanks or wells, transportation charges,
and the like.
Profiting by the experiences in California and elsewhere in the
use of oil for fuel, many industrial establishments in Texas
changed from coal to oil. Among the first was the American
Brewery, Houston, with two 200 h.p. and two 350 h.p.
boilers. The oil was the residue from the refining plant at
Corsicana-, and it was estimated that 75 barrels a day would
be required, as the coal consumption was about 25 tons a day.
After running for a while, it was stated that the steaming
capacity of the two 200 h.p. boilers using oil was equivalent
56 LIQUID FUEL AND ITS APPARATUS
to that of the two 350 h.p. boilers using coal, and the saving
of oil was about 33 per cent. The Star Flour Mills, Galveston,
installed oil burners in April, 1901, using about 35 barrels a
day for a 350 h.p. engine.
The first locomotive equipped for burning oil was delivered
to the Gulf, Beaumont and Kansas City Railway, June 20,
1901, and belonged to the Gulf, Colorado and Santa Fe Railway.
Up to the time of its reaching Beaumont it had travelled 450
miles, and consumed 42 barrels of oil, the tank having this
capacity. The Southern Pacific Railway burns oil west of El
Paso.
TESTS OF TEXAS OIL EFFICIENCY.
A report by Professor Denton states that the number of
barrels of oil equivalent to 2,240 pounds of coal was 4-23 for
one h.p. per about twenty square feet of heating surf ace, and
4-12 for one h.p. per 10 square feet of heating surface ; and it
appears that the average consumption of oil per ton of coal is
four barrels, and that under some conditions this falls to 3-50
barrels. There may be consumers who use even less than this,
but it is not thought that they represent the average practice.
Beaumont oil was used to operate a boiler at the plant of the
West Side Hygeia Ice Company, West 19th Street, N.Y. City.
There were three return tubular boilers, each 6 feet in diameter
and 18 feet long, containing about 1,900 square feet of heating
surface, two being used at a time to provide about 180 boiler
h.p. from buckwheat coal, with natural draught under a very
steady load throughout each 24 hours. One of these boilers
was fitted for the tests with the Williams Oil Burner.
Effect of the Oil on the Boiler and Furnace.
After the steam-raising test, the boiler was operated 24 hours
with oil, to use up all that remain of the 117 barrels provided
for the evaporative test. It was then cooled, and the oil- burning
apparatus removed to prepare the furnace for coal tests. The
boiler and furnace were then examined. No trace was found
of any action of the oil on the boiler. There was no oily matter
on the internal brickwork, nor any discolouration of the latter,
and there was less than eV of an inch of soot in the tubes,
which had been swept clear of ashes at the beginning of the
use of the oil.
The tests with oil were made at from 112 h.p. to 220 h.p.
The boiler was 6 feet in diameter and 18 feet long of the hori-
zontal return tube type. It had 100 tubes 2 J inches in diameter,
THE CHEMISTRY OF TEXAS PETROLEUM 57
and a grate surface of 45-5 square feet, i.e. 6 feet 6 inches by
7 feet inches. Height of chimney, 70 feet high by 42 inches
square. The resume of the tests is as follows
Resume of Tests with Leaumont Crude Oil.
Duration, hours ....
Horse power
3-5
146-9
8
122-7
11
189-7
13
138-0
11
220-1
Steam pressure (gauge), Ib. .
Feed temperature, degs. F.
Chimney temperature, degs.
F
87
69
374
86
90
360
86
70
398
86
90
370
86
74
425
Quality of steam.
Oil per hour per sq. ft. of
heating surface, Ib.
Dry steam per hour, from
and at 212 per sq. ft. of
heating surface, Ib.
Heating surface perh.p., sq.
ft
dry
0-181
2-73
12-6
dry
0-135
2-09
16-5
dry
0-226
3-52
9-8
dry
0-063
2-56
13-5
dry
0-263
4-08
8-45
Total dry steam per Ib. of
fuel as fired from and at
212F., Ib
Per cent, of steam used by
burner ...
15-29
3-6%
15-53
3-1%
15-55
4-8%
15-71
3-5%
15-49
4-8%
Net Ib. of dry steam per Ib.
of fuel fired from and at
212F. . .
14-74
15-05
14-80
15-16
14-75
Other figures are as follows
Dimensions and Proportions.
Grate surface, sq. ft 45-5
Water heating surface " 1,860
Position of damper Wide open
Area of opening of ash pits, sq. ft 1-8
Average Pressures.
Steam pressure, by gauge, Ib 86-5
Draught pressure, inches of water 0-37
Average Temperatures, Fahr.
Fire room 53-1
Feed water entering boiler 74 -C
Chimney gases 42-
Fuel
Weight of fuel as fired, Ib 5,39
Steam.
Quality of steam dry
68 LIQUID FUEL AND ITS APPARATUS
Water.
Total weight of water fed to boiler, Ib 70,798
Factor of evaporation 1-180
Equivalent water evaporated into dry steam from and
at 212F 83,542
Economic Results.
Feed water per Ib. of fuel as fired, Ib 13-13
Equivalent evaporation from and at 212F. per Ib. of
fuel as fired, Ib 15-49
Equivalent evaporation from and at 212F. per Ib. of
combustible, Ib . . 15-49
Efficiency.
Efficiency of boiler and furnace, or heat per Ib. of fuel as
fired, divided by calorific value per Ib. of fuel . 78-5%
Efficiency of boiler, or heat absorbed by boiler, per Ib. of
combustible, divided by calorific value per Ib. of
combustible 78-5%
Hourly Quantities.
Fuel as fired per hour, Ib 490-3
Fuel as fired per hour per sq. foot of grate, Ib. . . 10-78
Combustible per hour per sq. foot of heating surface, Ib. 0-263
Horse Power.
Horse power at 34-5 Ib. from and at 212 . . . . 220-1
Heating surface per horse power, sq. feet . . . . 8-45
Compositions of Fuel.
Per cent.
Carbon 85-03
Hydrogen 12-30
Oxygen and nitrogen 0-92
Sulphur 1-75
Heat Balance.
B.Th.U.
Utilized in production of steam 14,963
Due to combustion of hydrogen 1,245
Wasted in superheating water products .... 113
Wasted in dry chimney gases 1-837
Radiation and imperfect combustion 902
Heat per Ib. of fuel as fired, by calorimeter . . . 19,060
Heat per Ib. of combustible, by calorimeter . . . 19,060
The weight of oil per gallon was 7-66 pounds, or 322 pounds
per barrel of 42 American gallons of 231 cubic inches. The net
evaporation, per pound of oil. from and at 212F., was 15-1
pounds ; per pound of Pennsylvania bituminous coal, in the
best boilers at 10 square feet of heating surface per h.p. is
9'5 pounds ; of the semi-bituminous coals, such as Pocahontas,
THE CHEMISTRY OP TEXAS PETROLEUM 59
New River, Cumberland and Clearfield, it is 10-0 pounds, which
may be increased to 10-5 and 11 pounds by mechanical stokers,
or smoke-preventing devices.
Professor Denton calculates the comparative costs of oil and
coal as follows
Price of coal per ton Equiv. price of oil per barrel,
of 2,240 Ib. of 42 gallons.
$1.004/- #0.29 1 /2i
1.50 = 6/-
2.00 = 8/-
2.50 = 10/- . .
3.00 = 12/- . .
3.50 = 14/- . .
4.50 = 18/- . .
0.43 = 1/9|
0.56=2-4
0.85=3/6
0.99=4/1^
1.13=4/8|
1.28=5/4
These figures apply to bituminous coals mined west of Ohio.
In comparison with small sizes of anthracite, Pittsburg bitu-
minous and Maryland and West Virginia semi-bituminous coals,
and most or all British coals, oil must be sold at a less price,
inasmuch as these fuels are of a better quality than Western
and South -Western coals.
Evaporative Duty.
Professor Denton' s results show that the net evaporation
ranged from 14-74 to 15-16 pounds of water per pound of oil,
the h.p. varying from 112 to 220 and the burner steam con-
sumption from 3-1 to 4-8 per cent, of the boiler output. The
boiler utilized about 78 per cent, of the heat of the fuel, which
may be considered the best average boiler practice. It is also
to be observed that the results in actual practice showed that
98 per cent, of the total heat of combustion of the oil, as deter-
mined by the calorimeter, was accounted for by the steam pro-
duction, the chimney gases and a reasonable allowance for
radiation. Professor Denton thinks that for a higher horse-
power a net evaporation of 14-8 pounds of water is the best
economy that can be expected from the use of oil as fuel with
steam jet burners. This may be contrasted with 11-79 pounds
yielded by excellent No. 1 buckwheat coal.
Considering the objections that have been raised against the
use of crude oil, on account of its content of sulphur, it may be
said that many excellent steam coals carry from 1 -5 to 2 per cent
of sulphur, and that the average life of a boiler does not seem
to be impaired by their use. The amount of sulphur in the oil
used by Professor Denton was T63 per cent. Allowing that a
coal contains 1-7 per cent., an oil would have to contain 2-6 per
cent, in order to put as much sulphur into the products of com-
60
LIQUID FUEL AND ITS APPARATUS
bustion as the coal, equal horse-powers being assumed. It has
been ascertained that the use of coal carrying more than 3
per cent, of sulphur does not cause any greater depreciation of
fire-boxes, etc., than a coal of 1-7 per cent, of sulphur, and the
sulphur equivalent in oil corresponding to 3 per cent, in coal is
above 6 per cent. The objections to the use of crude oil, based
on its sulphur content, do not appear to be well founded, in so
far, at least, as concerns the integrity of fire-boxes, etc. Pro-
bably sulphur products are only seriously harmful when cooled
to moisture point.
The inflammability of crude oil has been the subject of critical
investigation. There was no inflammable vapour given off
below 142F. in Professor Denton's experiments ; and he does
not think that a pool of oil in a boiler room would become
ignited from a lighted match or from the dropping of a live coal
into it. It is also stated that a surplus of oil at the burner gave
rise merely to a thick smoke ; there was no explosion or excess
of pressure. /
One more point of a most important nature was brought out
by the test. It was not a new point, for other tests have estab-
lished the fact, and it is well known to those who study the
economies of fuel consumption. It is the comparative efficiency
of oil and coal referred to the heat balance.
Oil.
Coal.
B.Th.U.
Per cent.
B.Th.U.
Par cent.
Utilized in production of steam.
14,963
78-5
8,636
71-4
Evaporation of moisture in fuel and
due to combustion of hydrogen .
1,245
6-5
277
2-3
Wasted in superheating water pro-
ducts
113
0-6
23
0-2
Wasted in dry chimney gases
1,837
9-7
1,981
16-4
Wasted in unconsumed carbon in ash
768
6-3
Radiation and imperfect combustion
902
4-7
415
3-4
Heat per pound of fuel as fired, by
calorimeter
19,060
100-0
12,100
100-0
Heat per pound of combustible, by
calorimeter
19,060
14,680
This table shows that more heat units were given off by the
oil than corresponded with the total number of heat units
in the coal, and that the percentage of heat units used was
78*5 of those in the oil, as against 71-4 of those in the coal ;
in other words the oil was more efficient than coal. The saving
of the heat ordinarily wasted in dry chimney gases is especially
noteworthy, for the oil shows a waste of 9-7 per cent., as against
THE CHEMISTRY OF TEXAS PETROLEUM 61
16-4 for the coal. In comparison with coal yielding 12,100
B.Th.U. per pound as fired, and 14,680 per pound of combustible,
there is a decided economy in the use of crude oil under the
conditions maintained in this test.
That returns from consumers of oil show a difference of
43 per cent. (i.e. from 3*5 to 5) in the number of barrels of oil
equivalent to a ton of good soft coal, is evidence that ordinary
experience cannot be relied on to afford anything more than a
rough approximation. If the ordinary steam installations
were provided with smoke-preventing devices and mechanical
stokers, it is very probable that the economy in the use of oil
would not be so pronounced.
If all the economies possible in the use of the solid fuels
were maintained, the comparison between these and oil would
not be so strongly in favour of the latter. When smoke-
preventing appliances are installed alone or in connection with
mechanical stoking more particularly, a saving of more than
20 per cent, has been regularly obtained, with ordinary coals.
It is to be doubted whether ordinary practice with solid fuels
has attained its maximum economy. Establishments where
great attention is paid to all possible economies in fuel consump-
tion form the exceptions.
We may allow that the heat units in oil are more easily avail-
able for steam-raising purposes than the heat units in coal, and
that, per unit of heating power, we get better results from oil
than from coal. When we have once ascertained what we can
get from the oil, we can calculate the relative advantages in
the use of the two. It is, after all, a matter of cost, and each
particular installation must be considered on its merits.
Mexican Oil.
Mexico is now a large producer of oil. Mexican Fuel Oil
has the following characteristics :
Sp. gr., about 0-95 at 60 F.
Flash point, over 150 F. (open).
Viscosity, about 1,500 sees, at 100 (Redwood No. 1).
Calorific Value, 18,750 B.Th.U.
Sulphur, 3-5 per cent.
CHAPTER IV
THE CHEMICAL AND OTHER PROPERTIES OF PETROLEUM
IN a work of this description a deep study of the chemistry
of liquid fuels is not necessary. For fuller information
on petroleum chemistry the works of Sir Boverton Redwood
may be studied.
Petroleum is a mixture of a series of hydrocarbons of the
following types
1. C n H 2n+2 Methane Series.
2. C n H 2n Olefin Series.
3.
4.
5.
6.
7.
8.
-4
_ 6 Benzene Series.
-8
-10
-12
Those named occur in the greatest quantity and most fre-
quently. The first is a light gas in the form CH 4 , and as the
values of n in each series grow larger, the members of the various
series become liquid and finally solid.
Thus of the first or Methane series the first four are gaseous,
Methane, Ethane, Propane, and Butane. Series 1 is liquid
when n = 5 to 25. Above n = 25, the solids begin and generally
in all the series a higher value of n implies a higher boiling
point, and this rises with some regularity from n 9, by about
20C. = 36F. for each additional carbon atom. Hence the ease
with which fractional distillation can be carried on, the light oils
(gasoline, ect.) distilling off up to 150C., the illuminating oils
up to 300C., and the residuum being fuel oil, which still con-
tains the lubricating oils.
Dr. Paul, in discussing Aydon's paper, suggested that liquid
fuel had an advantage over solid fuel to the extent of 6,000
B.Th.U. per pound, which he claimed as the latent heat of
liquefaction, but this is elsewhere shown to be nearer the latent
heat of evaporation of carbon, while the latent heat of lique-
faction is scarcely credited with more than 5 per cent, extra
calorific power, and, as pointed out by Mr. C. E. L. Orde, the
CHEMICAL PROPERTIES OP PETROLEUM 63
Bombe calorimeter does not show anything like Dr. Paul's
figure. It is also probable that when carbon and hydrogen of
the liquid hydrocarbons united, they produced heat which more
than counterbalances the effect of the latent heat of liquefaction.
Indeed, methane gas, CH 4 , is known to produce, when burned,
very much less heat than calculation would appear to indicate.
Acetylene, on the contrary, produces more heat than calculable,
being endothermic.
Water in Oil.
Fuel oil and water do not readily separate. They do not
differ much in specific gravity, and oil is so viscous that the
globules of water cannot force their way out of it. But oil is
rendered more liquid by heat ; it expands more than water,
and separation is better effected by heating the oil. This is
best done locally near the surface of the oil in the bunker, so
that the heated oil is at once drawn ofi lor use, and heat is not
wasted in raising the temperature of the whole bunker.
The heat value of oil is reduced 13-14 B.Th.U. for each one
per cent, of water.
Thus 1 pound of oil worth 18,831 B.Th.U. mixed with 10
per cent, of water, gives a mixture the value of which per
pound is (18,831 x 0-9)- 131-4 = 16,816-5 B.Th.U., a differ-
ence of 1,915-5 B.Th.U., or a loss of nearly two pounds of
evaporation from and at 212F. Water also reduces the flame
temperature, lengthens the flame and moves the point of highest
temperature further along the flues, and so diminishes the values
of the heating surface. Mr. Orde lays down the conditions
which show perfect combustion as an opaque dazzling white
flame for six inches from the nozzle, becoming semi-transparent
and almost violet in colour at middle length, shading off to
red at the end. With water mixed in, the violet colour does
not appear (see chapter on Smoke) and the flame becomes dark
red and smoke-fringed. He states that at a temperature of
140F. = 60C. it required seven days to separate the water
completely in a tank of oil. Hence the use of a surface float
as in Fig. 14a.
His figures for the calorific value of various oils, as found by
the calorimeter, are as follows, and show a practical identity
of value in all, as may be expected from their chemical com-
position
Borneo 18,831 B.Th.U.
Texas 19,242
Caucasus 18,611
Burma 18,864
64 LIQUID FUEL AND ITS APPARATUS
According to Pelouze and Cahours, there are thirty different
hydrocarbons in petroleum, principally of the type C n H 2n+2 .
For n = 1 and n = 2 the substance is a gas. For n = 3 the
boiling point is 0C. = 32F. For n = 5 the liquid is very
volatile, the lightest isolated by the above chemists being CsHi 2 ,
boiling at 30C. = 77F. The fuel oils commence at C 8 H 18 ,
and go on to Ci 5 H 32 , beyond which C 20 H 42 to C 2 8H 58 are semi-
solid. The point of ebullition rises 20C. = 36F. for each
increment of carbon from C 8 H ]8 , which boils at 117 = 242- 6F.
to 197C. = 386'6F. for C 12 H 26 ; and 257C = 494'6F.
for Ci5H 32 . Similarly the specific gravity increases continually,
though less regularly, than the boiling point from C 5 H 12 , for
which it is 0-63, to C 15 H 32 , for which it is 0-83. The density
of the hydrocarbon vapours relative to air are 0-5 for n 1
to 7-5 for n =: 15, or a growth of 0-5 for each grade.
The Russian oils do not follow the same empirical composi-
tion as the American, but belong rather to the ethylene series
C u H 2n and the isomers, and to the benzene series CJH 2n _ 6 ,
of which benzene C 6 H 6 , is the characteristic member. In
" cracking " the oils during distillation even lower forms are
found : C n H 2n _ 8 ; C n H 2n _ 10 , which occur in the residues of
distillation. Water may exist in the proportion of 5 per cent,
for Baku oil to 10 per cent, for Borneo, but mineral matter is
always small, and ash scarcely exceeds 0-3 to 0-4 per cent., but
is an undesirable constituent for an engine, causing cylinder
scoring.
By " cracking," . the distilled liquid becomes more and more
stable, and the final residue is a mere coke.
Petroleum distils more easily when superheated steam is
blown through the still while below the " cracking " point.
The effect is peculiar to steam and cannot be secured with air.
It appears to be a sort of solution of the petroleum by the
steam, and Mr. Bertin, of the French Marine Militaire, con-
siders that this affords an explanation of the superior power
of steam in atomizing liquid fuel. A study of distillation
shows three sorts of petroleum suitable for fuel.
(A) Natural oils which have parted with their volatile
portions under the influence of sun and air and become
natural mazut.
Borneo oil which flashes at 100C. = 212F. is directly
employed as fuel, and Texas oil appears to possess little
other value than as fuel.
(B) Distillation residues, or mazut, which result from
boiling off all the more volatile portions.
CHEMICAL PROPERTIES OF PETROLEUM 65
(C) American distilled oils as per page 44. These oils
are very homogeneous and regular, but they emit in-
flammable vapours below the temperatures at which they
boil.
The Physical Properties of Petroleum.
These have already been partly treated of under the previous
head, but it may be added that in common with all hydro-
carbons and fats, petroleum and other liquid fuels become more
fluid and lose much of their viscidity when heated. Their
fluidity increases rapidly with heat. Hence the better atomiza-
tion possible with heated oils. Tests at Cherbourg on mazut
at different temperatures show that flow of oil through an orifice
of annular form half a millimetre wide was as follows in cubic
centimetres per minute
Temperature . . . 6C. 15 35 70 100
Flow 2-5 6-5 32 188 466
With water at 19C., the flow was 4,300 c.cm.
Mazut is easily heated, its specific heat being 0*42.
Petroleum has a rapid expansion coefficient, as much as
0-0007 per degree Centigrade. This helps it to rid itself of
water because, by heating the oil, both its sp. gr. and its re-
sistance are reduced, and water can the more easily gravitate
out.
Though petroleum has been supposed to be unaffected by
storage, mazut changes when exposed to air even more rapidly
than coal, according to M. Bertin, losing its fluidity and parting
with some of its calorific power ; experiment seems to be want-
ing in regard to such changes taking place in closed tanks and
not exposed to air. Any loss that may have been experienced
may perhaps be attributed to a gradual evaporation of lighter
oils still remaining. The lighter oils do possess the highest
calorific capacity, and their loss would therefore to some extent
reduce the calorific capacity of the residue.
In Russia the sp. gr. of oil for steam raising purposes at
17-5C. 63-5F. must not exceed 911 to 912, and oil must
contain no water, sand or alkali. When received the tempera-
ture must not exceed 50C. = 122F. and the flash point must
be above 140 or 150C. = 284 to 302F.
Certain railroads stipulate a density of 905 to 915 at 14R.
= 63-5F. There is no viscosity clause.
The Navigation Co. Caucase Mercure ask for a density of
926. The Russian Navyaccepts a flash point of 100C. =212F.
and a density of 950. In America the minimum flash point of
200F. is usual = 93'3C.
66 LIQUID FUEL AND ITS APPARATUS
Water in Oil.
To determine the water q the density d is found of the sample.
After heating for some time at 103C. = 217-5F. the density
is again found =d 2 . The quantity of water q is determined
by this relation (1 q) d 2 + q = d.
The coefficient of expansion per degree C. is assumed to be
0-000735 = 0-000408 per degree F.
MATERIALS.
In the utilization of fuels for steam-raising it is necessary to
have a knowledge more or less full of the whole of the materials
which will be employed either as fuels or structurally. Some-
thing must also be known of the environment in which such
substances will be employed.
A list of substances with which the engineer will be required
to deal therefore includes, besides the fuel itself, air, water,
cast-iron, steel, fire-brick, etc.
The conditions include the ordinary atmospheric tempera-
tures and moisture, the pressure of the atmosphere, and so on.
The units in which ideas are expressed must also be clear.
With this object separate sections have been given to the
subjects of Water, Air, and Heat in its various forms, to carbon
and hydrogen, the only two practicable fuels. A few notes
are given below concerning some of the other materials.
Cast-iron cannot be employed in the furnace, for it is rapidly
destroyed by the action of fire, even when not directly in the
flame. It should not be employed in the retort in which to
heat and to gasify even the h'ght-burning oils. Cast-iron tubes
have been tried for this purpose, and have been found to become
choked by a deposit of carbon, which may probably be due
to some affinity between the carbon in the iron and that in the
oil.
Cast-iron should never be employed as a material for any
vessel exposed to internal pressure.
Steel.
Steel is par excellence the material for all parts of boilers.
Like cast-iron, it will not withstand furnace temperatures
except when backed by water, as in the case of the plates of a
boiler.
Steel tubes only -^ in. thick are employed by Clarkson as
the retort coil in which paraffin is vaporized. These coils are
in the zone of flame, and vaporize the oil on its way to the
FIRE-CLAY AND FIRE-BRICK 67
burner which they surround. They possess a fair durability
owing to the heat absorbing power of the vaporizing liquid,
and they are found to keep free of carbon deposit.
F ire-Bricks.
The most important material for the furnace engineer is
fire-clay, a material which is found beneath seams of coal.
In a properly-set boiler for coal burning the whole interior
of the furnace and combustion chamber will be more or less
fluxed and run partially into drops or stalactites, which hang
from projecting edges. With liquid fuel, fire-brick is a most
necessary material for promoting combustion. It is a bad
conductor of heat, and has the property of resisting high
temperatures known as refractoriness. High furnace tempera-
tures will render even many fire-clays liquid at the surface.
Ordinary fire-clays contain 58 to 62 per cent, of silica, 36 to
38 per cent, of alumina, and from 1 to 3 per cent, of ferric oxide.
A large content of silica denotes a good and refractory brick.
Dowlais fire-brick contains 97 J per cent, of silica and less
than 2 per cent, of alumina, the remainder being oxide of iron,
with a trace of lime and magnesia.
Ganister, which is so much used in steel work, contains 89
per cent, of silica, 5| of alumina, 2J of iron oxide, and 2| per
cent, of material which is lost in burning.
A brick used in France is made from diatomaceous earth
which is nearly pure silica. These French bricks are very
porous and light, and when dry will float in water.
The best fire-clay comes from Stourbridge and Newcastle
in England, Glenboig in Scotland, and Dinas in Wales.
Makers of fire-brick supply a great variety of shapes, and
blocks can be had for seating purposes or for furnace work,
notably for over-fire arches and combustion chambers.
Fire-bricks are also made for threading on water tubes, so
as to build up refractory walls upon water tubes for the purpose
of securing the correct direction of gases and for promoting
perfect combustion and smokelessness. It is said that car-
borundum is very refractory indeed, and that when finely
powdered and made into a paint with soluble glass or silicate
of soda, and painted on bricks, it will greatly assist in their
preservation. Or the bricks may be dipped in the solution.
The carborundum surface is then most refractory.
Too little attention is paid by engineers to the fire-bricks
they use, and heavy expenses are incurred in maintaining
furnaces, expenses quite needless if proper attention is paid
to the selection of the bricks.
68 LIQUID FUEL AND ITS APPARATUS
When a furnace is to be repaired bricks are often purchased
from the nearest wharf, where they have lain exposed to
weather for weeks. In their water-saturated condition they
are built into the furnace and exposed to the full heat, with the
result that the interior of the bricks is disintegrated and the
bricks split up at once.
When a fire-brick is made it should be fired at a tempera-
ture as high as that to which it will be exposed when at
work.
The composition of bricks has a great influence upon their
durability in certain surroundings. A silica brick will run like
treacle in certain surroundings, and an alumina brick will fail
in others, but a brick of alumina is as refractory as one of silica
indeed, more so as regards its ability to withstand high
temperatures.
Having secured the right kind of brick, a sufficient supply
ought to be kept in store to enable them to become dry before
use. When built into place, a slow fire only must be made and
the heat got up gradually, so as to allow the bricks to dry
thoroughly before being highly heated. When a boiler is laid
off from work it should be closed up completely by shutting
the dampers and leaving the boiler and its brickwork to cool
as slowly as possible.
The most troublesome detail of a furnace is the arching
over the fire of a water tube boiler. The usual form of water
tube boiler is very smoky, and to cure this furnace must be
covered by a brick arch, and a capacious combustion chamber
must be employed beyond this, so that the furnace gases and
the air admitted above the fire may become well mixed and
burned at a high temperature. Even with the best of bricks
these arches are apt to fail when first fired, the face of the bricks
dropping off.
Messrs. E. and J. Pearson, of Stourbridge, make a special
brick for these wide flat arches, and supply a special cement
for use in putting them together. The cement is easily fluxed
by heat, and cements the whole surface of the arch into a solid
face, so that pieces of the brick cannot fall out. In time the
whole arch welds into a solid mass.
Such an arch ought to be built of properly-shaped bricks.
If plain rectangular bricks are used the arch pressure becomes
concentrated upon the intrados, and tends to flake off the
bricks and deprive the arch of its sustaining power. The
bricks should be of taper form so that they fit close in the arch.
What are known as blocks are used for these arches and for
similar purposes, and the above fire-brick manufacturers make
FIRE-CLAY AND FIRE-BRICK 69
special arch blocks with a tongue and groove joint for better
security.
In the formation of all important fire-clay blocks that will be
exposed to stress, as is an arch, it is of serious importance that
the clay be properly pugged into the mould. It is bad practice
to put a block of clay into the mould and put it under mechani-
cal pressure so as to force it to fill the mould. When this
pressure method is followed the plastic clay will be internally
fractured. Shearing planes are developed which form planes
of cleavage or fracture. The movement may be very slight,
but lines of weakness will be developed and the homogeneous
continuity of the mass of the clay will be destroyed. When
burnt, the adhesion along these planes of weakness will be
imperfect and when at work such a block will fail.
A really good arch should last a year if built from a firm
springing. The thrust of an arch is considerable and must all
be taken by the side walls, which, not as a rule carrying the
weight of the boiler, may not be very stable, and it is desirable
to tie them down to the foundation by through vertical bolts,
so as to form a stiff unyielding support for the arch springing.
The subject of fire-brick is one that has not been much
studied by engineers. Steel melters and others who deal with
high temperatures have paid attention to the question. The
burning of coal for steam raising purposes has, however, been
so invariably carried out at comparatively low temperatures
that the importance of fire-brick has not been perceived. When
a steam engineer begins to experience trouble with his furnace
side wall lining he casts about him for some means of meeting
that trouble, and his efforts may take the shape of a water box.
High temperature he regards, when it occurs, as a disagreeable
incident, to be checked and avoided. If he understood com-
bustion he would welcome the temperature as a means of
securing more perfect combustion, and would endeavour to
meet the trouble by the provision of suitable fire-brick.
The high temperatures obtainable with oil fuel bring the
fire-brick problem into greater prominence, and direct attention
to this most important material.
Some fire-bricks in a very hot furnace will soften and melt
away under long sustained heat. Others, more refractory or
infusible, crack and split up under sudden temperature changes.
A good brick becomes surface glazed, but the body remains
rough and porous. A granular nature and porous structure
are considered essential, and fire-bricks are not made of all new
clay. Old bricks are granulated and mixed up with the new
clay, so that the necessary texture is secured.
70 LIQUID FUEL AND ITS APPARATUS
Fire-clay is a mixture of silica and alumina in varying pro-
portions, each constituent possessing its own peculiar charac-
teristics. Usually silica exists in the proportions of about
two-thirds to one-third of alumina. The presence of alkaline
matter is prejudicial and induces fluxing. Thus lime is in-
tensely refractory of itself, and so is magnesia, but both of these
infusible substances fuse easily with silica, as also do oxides
of iron, soda, potash and other alkalies. These impurities of
fire-clays must be avoided. Mixing two clays of good quality
will not necessarily prove a success.
Silica, if otherwise pure, gives perhaps the most refractory
bricks, and certain French fire-bricks are made from infusorial
earth which consists of the minute siliceous shells of the diatom-
aceae. These French bricks, when dry, will float in water, their
specific gravity being under 1,000, owing to the numerous
voids and pores, but they are very tender and do not stand
well at the fire-grate level, where a tougher and harder brick is
necessary. The Dinas bricks of South Wales are very siliceous,
but are liable to split up if suddenly cooled, and are therefore
somewhat unsuitable for hand-fired furnaces, but should be
excellent for mechanically-stoked furnaces with self-cleaning
grates. Probably the best boiler furnace brick is one high in
silica, yet containing a fair proportion of alumina and free from
alkalies. Such a brick combines infusibility and toughness
for puddling furnaces, coke ovens, gas retorts and other high
temperature uses, and it must be remembered that the kind
of furnace advised by the author for bituminous fuel com-
bustion, and adopted from sheer necessity with liquid fuel, is
exposed to temperatures more resembling those of metallurgical
furnaces than the starved temperatures of the common un-
scientifically set steam boiler.
A sample of the clay from the Glenboig Star Mine, as analysed
by Edward Riley, F.C.S., after calcination, gave the folio wing
results
Per cen\
Silica 65-41
Titanic acid 1-33
Alumina 30-55
Peroxide of iron 1-70
Lime 0-69
Magnesia , 0-64
Potash and soda . 55
100-87
Sir Frederick Abel analysed a Glenboig brick, at the Royal
FIRE-CLAY AND FIRE-BRICK
71
Arsenal, Woolwich, as follows. The 'brick was taken from
stock
Per cent.
Silica 62-50
Alumina 34-00
Iron peroxide 2-70
Alkalies, loss, etc 0-80
100-00
Mere analysis, however, does not tell everything. For
instance, in this last analysis the silica and alumina were largely
in chemical combination, and this is more valuable than the
mere mechanical combination of the constituents.
To make a good brick the clay must be suitably weathered
so that any iron nodules may separate out. The clay is ren-
dered smoother and more solid for articles requiring such
qualities, as seating blocks ; for high temperatures, porosity
is given by the addition of old bricks.
All defects of shape are produced in the drying stove after
moulding. Stoving is therefore a most important operation,
and a brick must be practically dry before firing, which is
gentle at first until the bricks are hot and perfectly dried out.
Then the kiln is put on to full fire, and the temperature must be
maintained until the bricks cease to shrink. A brick which
has not been fired at a full temperature will shrink further if
put to work at a higher temperature. The total shrink from
the moulded size is about 8 \ per cent, of the bulk, or about 2
per cent, linear measure. In any case no shrinkage should
remain in a brick, or it will shrink when put to work and pull
the brickwork in pieces.
Professor Abel, F.R.C., gave various analyses of fire-clays
as per the annexed table, from which the excellence of Stour-
bridge and Glenboig bricks is plainly evident in the small
percentage of alkalies.
Description of Fire-clay.
Silica.
Alumina.
Iron
Peroxide.
Alkalies,
Loss, etc.
Kilmarnock
Stourbridge
5940
65-65
67-00
35-76
26-59
25-80
2-50
5-71
4-90
2-64
2-05
2-30
66-47
26-26
6-33
0-64
58-48
35-78
3-02
0-72
63-40
31-70
3-00
1-90
Newcastle
59-80
63-50
27-30
27-60
6-90
6-40
6-00
6-50
Glenboig
62-50
34-00
2-70
0-80
1$ LIQUID FUEL AND ITS APPARATUS
For the following miscellaneous information the author is
indebted to the Glenboig Company
Shape and Size.
Weight.
,000 Square Bricks
Inches.
9 X 4| X 3
Tons.
4
,000
9 X4 1 X2 1
31
,000
9 x4J x2|
"3
3
,000 End or Side Arch
,000 ...
,000 ...
,000 Cupola
,000 Pup Bricks
. 9 x 4 J x 3 and 2
. 9x4^x2| and 1|
. 9x4^x3 and 21
9 x 4 and 3x3
9 x 3 x 2
3*
2|
3f
3J
2
,000
9x2|x2
11
1,000 Scone Blocks
9 x4| x2
- 1 3
si
1,000
9x4|xl|
^3
2
1,000 Crown or square
9x6 X 3 _
51
*l
One inch =Millimetres 25-4. One Ton = Kilogrammes 1,016.
Miscellaneous Weights and Measurements.
STACKED LOOSE.
1,000 9 in. x4 in. x2 in. =66 cub. ft.
1,000 9 in. x4J in. x3 in. x3 in. =80 cub. ft
BUILT WITH FIRE-CLAY.
1 square yard 9 in. work requires :
109 bricks 9 in. x 4| in. x 2 in. and 2 cwts. ground fire-clay, or 92 bricks
9 in. x4| in. x3 in. and If cwts. ground fire-clay.
A rod (English) of brick = 11J cub. yds.
A rood (Scotch) of brick = 16 cub. yds.
FOR PAVING.
1 yard superficial requires 16 tiles 9 in. x9 in.
18 tiles 12 in. x6 in. x2 in.
32 bricks 9 in. x 4| in. x 3 in. laid flat.
48 bricks 9 in. x 4| in. x 3 in. laid on edge.
One 9 inchx4| in. x3 in. =9 Ib.
17| cub. ft. blocks = 1 ton.
334 bricks = 1 load.
1,500 to 2,000 = 1 railway truck.
3,100 to 3,200 9 in. x 4^x21 in. bricks = 1 railway truck (Continental)
6 to 8 tons ground fire-clay = 1 railway truck.
8 bags ground clay = l ton.
3 casks ground clay = l ton.
21 cub. ft. of dry ground fire-clay, firmly packed = 1 ton.
Fire-clay suffers no deterioration of quality from rain.
For shipment it is packed in barrels or bags.
The usual shipping size of fire-brick is 9 in. x 4| in. x 2| in.
The Glenboig Company make special silica bricks from
English chalk flints; they weigh 2 tons 12 cwt. per 1000,
FIRE-CLAY AND FIRE-BRICK
73
9 in. X 4J in., x 2J in. They also make a highly refractory
brick from Gartcosh clay, which analyses as below, according
to W. WaUace and Jno. Clark, Ph.D., F.C.S., etc.
Silica . . .
Titanic acid .
Alumina
Peroxide of iron
Lime .
Magnesia .
Potash . .
Soda
Per cent.
61-90
2-09
32-34
3-02
0-37
0-20
0-06
0-30
100-28
The proportion of alkalies is thus small and the brick is
solid and has small shrinkage from the mould and weighs 131
pounds per cubic foot. The ganister bricks of the Company,
which are made from what appears to be a soft sandstone,
analyse as below
Gartcosh Ganister.
Gartcosh Silica.
Silica
Titanic acid ,
87-06
Trace
74-10
0-20
Alumina
11-24
22-32
Oxide of iron
Lime
0-69
Trace
Trace
2-28
0-48
0-34
Potash
0-61
Soda
0-33
0-38
99-93
100-00
Bricks for Oil-fired Furnaces.
Where bricks are applied to oil-fired furnaces the intense
local heat of the oil furnace of course burns the brickwork
away in time, or rather melts it on the surface immediately
in contact with the flame, causing it to run down and hang in
the form of stalactites, but it takes a considerable time to wear
through nine inches of brickwork, and the cost of the bricks
is more than compensated for in the increased efficiency of the
furnace.
It is often the case that furnaces and combustion chambers
lined with fire-brick come to grief through being badly built
rather than from the bad quality of the bricks used ; at the
same time, good work will not make up for bad bricks. The
usual type of liquid fuel furnace for kilns is as shown in the
74
LIQUID FUEL AND ITS APPARATUS
annexed illustration, Fig. 1, the burner being so set that the
fuel in vaporized form is more or less concentrated in the centre
arch at x. The consequence is that the intense heat is
localized and the brickwork runs down into slag. Various
methods have been tried to get over the difficulty one is to
cover the grate with broken fire-brick, or coke, but this was not
altogether successful. Another idea is to protect the piers
x
Fig. 1.
of the arches with bricks piled up loosely in semicircular form,
with the concave side facing the burner, stacking them with a
space between, and crossing the open space with another row
of bricks, as shown in plan, Fig. 2, thus distributing the heat
over a large area of brick surface.
The bricks would melt after a time, but they could be raked
out and a fresh lot put in, and the arches would be saved con-
siderably.
2.
In the case of over-fire arches, Fig. 3, for water tube boilers
having a wide span, the best type of brick to use is what is
known by the name of the Bullhead or End- wedge, as shown
in Fig. 4, or the special bricks of Fig. 5.
In all cases fire-bricks should be set with as little jointing
material as possible, and for arches the bricks should be speci-
ally made to work to the desired radius. Any attempt to use
FIRE-CLAY AND FIRE-BRICK
75
SECTION ON A B
r
ELE v ATION
Fig. 3.
ordinary rectangular bricks is fatal. The pressure becomes
concentrated on the underside of the arch, as in Fig. 6, and the
mass has no rigidity bricks begin to fall out and the arch is
ruined.
The bricks should be set with finely ground fire-clay made
up with water to the consistency of thick paint. The brick
should be dipped in this, and then rubbed into contact with its
neighbours.
Fire-clay is made up into specially shaped bricks and lumps
for different purposes, and bricks and blocks can be made to
meet the special requirements in furnace work, but unequally
proportioned lumps must be avoided on account of internal
stresses, fire-clay having its limitations in this respect, as ex-
plained above, just as cast-iron has The best plan is to con-
76
LIQUID FUEL AND ITS APPARATUS
suit a reputable maker. The most usual course is to decide
on all other points of construction and make the best job
* *
LARGE
ARCH 6RIC*
possible on what are generally considered incidentals, such as
furnace linings, whereas by taking the limitations of a necessary
material into consideration in the first place, much expense and
trouble may be saved.
Good fire-bricks should
have sharp angles, and
give a metallic ring on
being rubbed together.
They should be kept some
time before use in a dry
place. Bricks sodden with
rain and heated up quickly
SPRINGER will tend to burst.
Fig. 5. Various substances hav-
ing been suggested as sub-
stitutes for fire-brick, it may not be out of place to say
something as to the varieties of fire-clay goods.
The following is the classification generally adopted
I Siliceous fire-clay goods.
II Aluminous
III Argillaceous
IV Carboniferous
Nos. I and II are the
most generally used.
No. IV is a mixture
of carbon and clay, the
carbon being in a crys-
tallized state as used
for arc lamps, etc., or
amorphous as graphite,
the latter being used
for the manufacture of crucibles, etc. Carbon blocks have
Fig. 6.
FIRE-CLAY AND FIRE-BRICK 77
been suggested, but, apart from the excessive cost, the carbon
combines with any free oxygen in the furnace gases and is
consumed.
No. II. A mixture containing a greater portion of alumina
than pure clay. This also is too costly for general use.
Lime is sometimes used as furnace lining for electrical kilns
and will withstand the intense heat of the voltaic arc, but as it
retains the property of being hydrated in air, its use is neces-
sarily very limited. This class of fire-clay goods is known as
basic.
Siliceous fire-clay goods are composed almost exclusively of
silica.
Argillaceous fire-clay goods are composed of silica and alumina,
and are next in degree of refractoriness to aluminous goods.
It should be borne in mind that the foregoing are each
adapted to particular purposes, and the proper admixture of
clays for any desired purpose is a matter that only long experi-
ence and scientific knowledge can determine, the physical as
well as the chemical properties of clay having to be taken into
account.
SUoxicon.
A very refractory material is Siloxicon, a product of the
electric furnace, consisting of carbon, silicon and oxygen formed
at a temperature of 4,000 to 5,000F., and therefore very
refractory at ordinary temperatures. It is a loosely coherent
mass as formed and is ground to pass a 40 2 sieve. It is an
amorphous grey-green compound when cold, becoming light
yellow at 300F. It is insoluble in molten iron, neutral to
acid and basic slag, indifferent to all save hydrofluoric acid,
and is unattacked by hot alkaline solutions. It is formed into
bricks by simple pressure, when damp, and fired. It is neutral
to clays and will not oxidize, and appear likely to form a valu-
able furnace lining where oil fuel is employed.
CHAPTER V
COMBUSTIBLES AND SUPPORTERS OF COMBUSTION
Carbon.
RBON is an element which has the following properties.
Its atomic weight is 12 and it is tetravalent in chemistry.
It is found free in nature in various forms, but is usually
considered to exist only in three allotropic modifications, viz.
(1) The Diamond, which is practically pure crystallized
carbon.
(2) Graphite, not entirely amorphous.
(3) Charcoal, an amorphous substance, is considered to
include all other forms of carbon.
The following figures give the values of the various forms
of carbon in calorific value or heat absorption
COMBUSTION.
State of 1 pound or 1 kilo, of Carbon.
Product of
Combustion.
Calories
per kilo.
B.Th.U.
per pound.
CO
2,175
3 915
CO 2
7,859
14,146
CO 2
7 900
14 222
Amorphous
CO
C0 2
CO
2,453
8,137
5,684 +e
4,415
14,647
10,232 +e
OOo
11 370 +e
20 463 +e
2 pts. of CO per part of C. .
CO 2
5,683
10,231
HEAT ABSORBED BY METAMORPHIC CONVERSION.
Diamond .
.... to
Vapour
3,508
6,316
Graphite
Amorphous .
3,468
3,231
6,241
5,817
Graphite
41-5
74-7
Graphite
.
Amorphous
277-0
235-7
499-0
424-3
78
COMBUSTIBLES AND SUPPORTERS 79
The above figures are calculated from the determinations
by Berthelot of the heat of combustion and formation of the
molecule (see Thermochimie, par M. Berthelot, Paris, 1897).
Except that these figures point the lessons that form and
state are dependent upon heat, apparent or latent, no further
interest centres on the crystalline modification of carbon,
which is too scarce to employ as a commercial fuel.
The first oxidation of ordinary carbon with one atom of
oxygen to CO produces 4415 B.Th.U. =2,453 cal. per pound
and per kilogram respectively.
The second oxidation produces a further 10,231 B.Th.U.
5,684 cal. The total heat produced by complete combustion
is thus 14,647 B.Th.U. =8, 137 cal.
The difference (5,684-2,453) between the two oxidations
is 5,817 B.Th.U.= 3,231 cal., and Berthelot considers that this
difference is less than the latent heat of vaporizing carbon by
some unknown amount. In the absence of a knowledge of
what it amounts to, it is usual to say that the difference is the
latent heat of vaporizing carbon, just as 967 is the latent heat
of steam.
In order to liquefy, carbon mast absorb heat, but free liquid
carbon is unknown. Solid carbon burns directly to dioxide
gas without going through the intermediate liquid state,
exactly as a piece of ice will disappear in a dry cold wind below
freezing temperature without passing through the intermediate
state of water. The liquid state is not imperative, and carbon
is only found liquid when combined with other substances.
It forms a liquid with sulphur as carbon bisulphide CS 2 . It
is liquid with hydrogen and oxygen in alcohol, and it is liquid
with hydrogen alone in the many hydrocarbons with which we
are at present concerned. By so much as the liquid form
already represents heat rendered latent in reducing a solid to a
liquid, by just so much should liquid fuel possess a greater
calorific value per unit of its contained carbon than a similar
weight of solid fuel. The same argument applies with equal
force to the hydrogen, but to some extent conversely. The
calorific capacity of hydrogen is given in terms of the gas
burned as gas. In solid coal the hydrogen is part of a com-
pound solid, and it is scarcely correct to calculate the calorific
capacity of a solid fuel in terms of its hydrogen at gas value,
for undoubtedly heat is absorbed in rendering the hydrogen
gaseous from its solid combined state in coal. Similarly, in
liquid fuel the hydrogen is in liquid form and must be gasified.
It is possible that the benefit derived from the liquidity of the
carbon is neutralized by the liquidity of the hydrogen.
80 LIQUID FUEL AND ITS APPARATUS
The properties of carbon are summarized in the following
table
PROPERTIES OF CARBON.
Atomic weight 12
Specific heat 0-1468 to 0-285
Heat of combustion per kilo, to CO 2 . 8,137 cal. =32,285 B.Th.U.
pound to CO 2 . 14,647 B.Th.U. =3,691 cal.
Temperature of vaporization . . . 3,600C.=6,512F.
combustion to CO
In air ..... 1,485C. =2,705F.
In oxygen . . . 4,292C. =7,757F.
Air required to burn 1 unit to CO . . 5-797
Oxygen 1 ,, . 1-334
1 ,, C0 2 . . 2-667
Air 1 CO 2 . . 11-594
Temperature of combustion to CO 2
In air 2,753C. =4,988F.
In oxygen 10,226C. =18,440F.
Heat of combustion to CO
per pound 4,415 B.Th.U. = 1,112 cal.
per kilo 2,453 cal. =9,733 B.Th.U.
Weight of vapour per cubic metre (ideal) 1-072 k. =0-06696 per cubic
foot.
The atomic weight of carbon being 12 and that of oxygen 16,
the formula for carbon monoxide = CO tells that there are 12
parts of weight by carbon in each 28 parts of the gas. Hence
1 pound of carbon unites with Impounds of oxygen to produce
2J pounds of gas.
When burned to dioxide = C0 2 there are 12 parts of carbon
to each 32 parts of oxygen, and 1 part of carbon unites with
2 1 parts of oxygen to produce 3f parts of gas.
As oxygen is not available for combustion except in the form
of air, and as it is not desired to produce CO, the essential
figures to remember are that eachunit weight of carbon demands
a minimum of nearly 11-6 units of air.
In the foregoing table the temperatures are those calculated
on the assumption that the specific heat of the gases produced
remains the same at all temperatures and that combustion is
complete. Neither assumption represents actual facts, for the
process, of combustion is delayed as temperature rises, and
even if it were not, the specific heat increases and holds back
the temperature. Since in practice there are so many effects
of dilution, the calculation of total heat can be correctly done
on a basis of constant specific heat. If a final temperature of
great intensity is found, a correction can always be applied
after all calculation has been made.
COMBUSTIBLES AND SUPPORTERS 81
The various figures given in this book differ somewhat from
many previously accepted figures, owing to the progress of the
science of thermo-chemistry. The figures given herein are
those given by Berthelot in his work, Thermochimie, 1897.
Carbon burned to CO or directly to C0 2 does so with simple
incandescence. No flame is produced. Carbonic oxide = CO,
however, if formed by the burning of carbon with insufficient
air, will burn with a blue flame if provided with air.
The hydrocarbon gases burn with a reddish, a yellow, or a
white flame, according to surroundings and temperature, the
flame consisting of glowing carbon in an atmosphere of hot gas.
Hydrogen.
Hydrogen shares with carbon the monopoly of the term fuel,
for there are no commercial fuels except carbon and hydrogen
or their joint compounds. Hydrogen is a gas. Its atomic
weight is 1, and being the lightest known element, it serves
as the unit of atomic comparison.
Its physical and other properties are as follows
Atomic weight and density .... 1
Specific heat. Constant vol 24146
,, pressure . . 3410
Weight per litre 0-08961 grams =0-000089 k.
cubic foot 0-00559 pound = 0-002536 k.
Cubic feet per pound 178-83=5,063-4 litres.
Litres per kilogram 11,160 = 394-15 cubic feet.
Heat of combustion per kilo. } ( 34,500 cal. = 136,900 B.Th.U.
pound !ToOC. | 62, 100 B.Th.U. =15,650 cal.
cubic foot I =32F. 1 347 B.Th.U. =8745 cal.
litre I 3-091 cal. = 12-264 B.Th.U.
Specific gravity, water = 1 .... 0-0714 when liquefied.
Point of vaporization 33 abs. C. =60 abs. F.
freezing or liquefaction . . . 16-7 abs. C. =30 abs. F.
Temperature of combustion
(nominal) in oxygen . 6,762C. =12,202F.
air. . . 2,513C.=4,554F.
Ratio of air required to burn 1 unit weight 34-785
1 unit vol. . 2-39
>, oxygen weight . 8-00
t , ,, oxygen vol. . . 0-50
Heat of combustion per kilo, (result in
vapour) 29,150 cal. =115,434 B.Th.U,
Heat of combustion per pound (result in
vapour) 52,290 B.Th.U. = 13,177 cal.
The heat of combustion of hydrogen is 62,100 B.Th.U. per
pound. This assumes that the products of combustion are
rejected in a liquid state. In furnace work, however, the gases
of combustion always leave at temperatures above 100C.,
82 LIQUID FUEL AND ITS APPARATUS
and consequently the gases carry off with them the latent heat
of evaporation. This reduces the available heat to 52,290
B.Th.U per pound, or 29,150 cal. per kilogram, or say 293
B. Th.U. per cubic foot and 2-612 cal. per litre. This fact must
be borne in mind when calculating results.
SMOKE PRODUCTION. Hydrogen ignites at a temperature
below that necessary to ignite carbon. Its affinity for oxygen
is greater and, in presence of an insufficient supply of air, the
hydrogen of a hydrocarbon fuel will first secure its share of
oxygen and the carbon will appear as soot. Sudden cooling
of a hot hydrocarbon gas is also said to produce soot, but it is
questionable if soot is really produced without a certain amount
of combustion of the hydrogen.
The following table gives the temperature of ignition of a few
of the hydrocarbon gases, according to Mayer and Munch
CH,
667C.
1,232F.
Ethane .........
C 2 H 4
616C.
1,141F.
547C.
1,017F.
580C.
1,076F.
504C.
1,004F.
Hydrogen burns with a transparent blue flame. Its com-
pounds with carbon burn with a light-giving flame consisting of
incandescent carbon particles carried in an atmosphere of gas.
These hydrocarbons are exceedingly numerous, and range
from gases of small density through every shade of liquid to
solids like naphthalene and paraffin wax.
The percentage of carbon and hydrogen in a petroleum of
any degree of refinement does not vary far from 84 of carbon
and 16 of hydrogen, corresponding with a mean formula of
Air.
Oxygen being necessary for combustion, there is only one
source whence it can be obtained in large quantity, viz., the
atmosphere.
The atmosphere contains by volume
20-84 vols. of oxygen ) , . , ,
79-16 nitrogen j rs
There are also small quantities of other gases, the principal
of which is carbon dioxide, C0 2 , present to the extent of only
0-0004, and negligible for present purposes.
COMBUSTIBLES AND SUPPORTERS 83
By weight the atmosphere contains
The mean atmospheric pressure at sea-level is assumed by
Rankine to be 14-704 pounds per square inch, at a temperature
of 32F. 0C. The mercury barometer then stands at
29-922 inches. At this pressure water boils at 212F. = 100C.
The metrical atmosphere also measured at 0C. is 760 mm.
of mercury column = 29-922 inches. At the ordinary tem-
perature of 57-8F. the mercury barometer of 30" = I atmo-
sphere, and at all ordinary temperatures and for purposes of
steam engineering it may be called 30 inches.
Expressed in metric measures, one atmosphere is 1-0333
kilos per square centimetre at Paris.
A mercury column giving 14-704 at London will give 14-6967
= 1-0333 kilos at Paris and 14-686 at New York.
The pressure and density of the atmosphere varies with the
elevation above sea level, and may be thus calculated
H = 60,000 (1-477-log R), where
R is the elevation in feet above sea level ;
H is the barometric height in inches at elevation R, and 1-477
log 30.
Hi^h elevation requires consideration in regard to the relative
volume of air for furnace supply.
Air at all temperatures for purposes of furnace work behaves
as a perfect gas.
The weight of a cubic foot of dry air at 62F. is 532-5 grains.
If saturated with moisture the weight is 529 grains. The
specific gravity of air is 819 times less than water, and one
pound of air measures 13-146 cubic feet at 62F.
The standard barometric pressure of 1 atmosphere or 14-6967
pound per square inch at Paris = 1-0333 k. per cm. is curiously
approximate to 1 k. per cm 2 . or to 14-21 per square inch.
Approximately 1 atmosphere is equal to a pressure of 1 k.
per square centimetre.
The density of air relative to hydrogen is 14-44, its specific
heat is 0-2375 at constant pressure, and 0-1686 at constant
volume. One pound of air measures 12-385 cubic feet at 0C.
=32F., and 1 cubic foot weighs 0-08073 pound. One litre of
air weighs 1-292743 grams at 0C. and 760 mm.
Oxygen.
Oxygen is the active constituent of the atmosphere in pro-
moting combustion. It combines with most elements to form
84 LIQUID FUEL AND ITS APPAEATUS
oxides with evolution of heat. The atomic weight of oxygen
is 16 and it forms one stable oxide with hydrogen H 2 (see
Water) and two oxides with carbon, viz.
(1) Carbon monoxide or carbonic oxide = CO, which
contains 12 by weight of carbon and 16 by weight
of oxygen, and
(2) Carbonic acid or carbon dioxide = C0 2 , containing 12
by weight of carbon to 32 of oxygen.
The density of oxygen is 16 ; its weight per cubic foot is
0-08926 pound at 0C. = 32F. and 11-203 cubic feet weigh one
pound.
Its specific heat at constant pressure is 0-217 and at constant
volume 0-1548. One litre of oxygen at 0C. and 760 mm.
weighs 1-4293 grams.
Nitrogen.
This gas constitutes about four-fifths of the atmosphere.
It is a colourless gas and very inert. It does not support com-
bustion, but acts by dilution to restrain its intensity and to
reduce the temperature.
Its density is 14, specific heat = 0-244 at constant pressure,
and 0-173 at constant volume. It weighs 0-07845 per cubic
foot and 1 pound equals 12-763 cubic feet. One litre of nitrogen
weighs 1-2505 grams at 0C. and 960 mm.
The weight of nitrogen in the atmosphere is 3-32 times that
of oxygen. It is, therefore, the cause of much dilution of the
products of a furnace, and reduces the theoretical temperature
of combustion to a figure much below that of combustion in
oxygen.
WATER AND STEAM.
Steam is produced by heating water to such a temperature
that the elasticity of the water vapour becomes greater than
the superincumbent air pressure of about 14-7 pounds per
square inch at the level of the sea. (See Air.)
Pure water is not found in nature, but is closely approximated
in sain caught on hill-tops distant from towns, and in streams
which flow off the barren country associated with granitic rocks,
the millstone grits, and certain other geological strata. Water
is an oxide of hydrogen, and its chemical formula is H 2 0. It
consists of 2 parts by weight of hydrogen to 16 parts of oxygen,
and it is produced when hydrogen is burned, the combustion
setting free a large amount of heat. (See Hydrogen.)
Water is used as the unit point in many physical data. The
specific gravity of all other substances is referred to that of
COMBUSTIBLES AND SUPPORTERS
85
water as unity. So also is the specific heat of all other sub-
stances, and excepting hydrogen, the specific heat of water is
the highest of any known body. The amount of heat necessary
to raise the temperature of 1 kilogram of water from 0C. to
1C. is called the great calorie or simply the calorie, the little
calorie having reference to the weight of one gram only, and
being employed by chemists and physicists.
Similarly the heat necessary to raise the temperature of
one pound of water from 32F. to 33F. is called the British
Thermal Unit or B.Th.U. Thus 1 calorie = 3-9683 B.Th.U.
and 1 B.Th.U. = 0-252 calorie.
Weight.
One gallon of pure distilled water at 62F. weighs 10 pounds
by Act of Parliament. The American or old wine gallon
weighs 8J pounds and measures 231 cubic inches, as com-
pared with the British Imperial 10 Ib. gallon of 277-479 cubic
inches (Chaney). One cubic decimetre of water or 1 litre
weighs, by law, 1 kilogram, the kilo, being 2-204 pounds.
Thus 1,000 k. weigh very nearly 1 ton.
A column of water 1 foot high exerts a pressure at the base
of 0-434 pounds per square inch. Thus a pressure of 1 pound
per square inch represents a column of 2-3 feet. Hence an
atmosphere of pressure is equivalent to 33-8 feet of water
column.
Compressibility.
Water is nearly incompressible, the coefficient at 0C.
32F. being -000052, and at nearly 53C. = 127F. = 0-0000441.
It is thus negligible.
Expansion.
Water changes its volume with change of temperature, but
not to an amount that is of serious account in steam engineering.
Temp.
Weight.
Temp.
Weight.
Temp.
Weight.
212F.
250
300
59-71
58-81
57-26
350
400
450
55-52
53-64
50-66
500
550
62
49-61
47-52
62-2786
102
62-00
158
61-00
203
60-00
The foregoing table gives the weight per cubic foot of water
86
LIQUID FUEL AND ITS APPARATUS
at various temperatures, showing that the maximum expansion
in the open air does not reach 5 per cent.
Water attains its maximum density at 4C. =39-lF.
It becomes solid at a temperature of 0C. = 32F., the freez-
ing point of water being employed in fact as the of the
Centigrade thermometers.
Ice has a specific gravity of 0922 and a specific heat of 0-504.
To reduce 1 pound of ice at 32F. 0C. to water also at
32F. requires 142 B.Th.U. = 35-78 calories. The latent
heat of water is thus said to be 35-78 calories or 142 B.Th.U.
per pound, or 78*86 calories per kilogram.
Specific Heat.
The specific heat of water, called 1-00 at 0C. 32F., is
not uniform, but increases slightly with increase of temperature,
as per the following table :
Temp. F.
Specific Heat.
Temp. F.
Specific Heat.
32
0000
248
1-0177
50
0005
266
1-0204
68
0012
284
1-0232
86
0020
302
1-0262
104
0030
320
1-0294
122
0042
338
0328
140
0056
356 .
0364
158
0072
374
0407
176
0089
394
0440
194
0109
410
0481
212
0130
428
1-0524
230
0153
446
1-0568
As at the above temperature the bulk of water is increased
in a much greater ratio than the specific heat, the total heat
per cubic foot will decrease somewhat with rise of temperature.
As the total heat contained in one pound of steam measured
from 32F. is nearly 1,200 B.Th.U., this amount of heat is
more or less thrown away when steam is used to atomize liquid
fuel. The gases never leave a furnace below 212F., and every
pound of steam carries off its load of 967 units of latent heat
to the chimney. Air being already a gas, and necessary to
combustion, causes no loss in this manner, but it requires
power to compress air, and some steam is thereby used, but,
especially at sea, such steam can be condensed and does not
therefore lead to a loss of fresh water. No extra work is
COMBUSTIBLES AND SUPPORTERS 87
thrown upon the evaporation plant. Water may be split up
by heat into its two constituent gases. In this process of
dissociation or decomposition exactly as much heat is absorbed
as was produced by the combination of the gases when the
water was formed. This plain chemical fact is ignored by
those who dream of steam as fuel, and imagine that steam jets
introduced into a furnace will decompose and burn with any
effect in increasing the total heat production of the furnace.
Steam thus employed is useful as a mechanical draught pro-
ducer only, or there may be some truth that hydrocarbons
burn better in the presence of moisture. But no further
claim is tenable.
Useful Figures.
In the calculations of the steam engineer it is convenient to
remember that the square of the diameter of a pipe or a pump
barrel gives the weight of water in a yard length of pipe. Thus
a six-inch pipe holds 36 pounds or 3*6 gallons per yard. Again,
1 pound of coal should evaporate 1 gallon of water ; 1 gallon
of water will give steam to work in the best engine yet made
at the rate of 1 h.p. hour. Two gallons will serve an ordinary
compound engine per h.p. hour, and 3 gallons a good non-con-
densing engine for each h.p. hour. Approximately, too, 1,000
B.Th.U. generated represents one pound of steam, so that the
number of thousands of units capacity of a pound of fuel
represents the theoretical evaporation in pounds of water.
Solubility of Salts.
As a rule this increases with the temperature, but at a slow
rate, except for sodium chloride and a few other exceptions.
For the sulphates of magnesium and potassium and the chlorides
of barium and of potassium, solubility is proportionate to the
increase of temperature.
With sulphate of soda the solubility first increases and then
falls off again.
The solubility of calcium sulphate decreases with tempera-
ture.
The following table gives the solubility of a few salts at various
temperatures in parts per 100.
The solubility at 212F. is really at a higher temperature,
being the solubility at boiling point, which is always raised
slightly by the solution of a salt.
'88
LIQUID FUEL AND ITS APPARATUS
Temperature.
32F.
70F.
212F.
Calcium chloride . *
Magnesium sulphate
Potassium carbonate
chlorate
chloride
400-0
24-7
100-0
3-33
29-21
13-32
35-0
80-0
8-0
34-0
30-0
130-0
60-0
60-0
240-0
sulphate ....
Sodium carbonate ...
6-97
12-0
21-7
26-0
45-1
,, bicarbonate ....
6-9
35-5
9-6
36-0
39-6
5-02
22-0
42-6
Barium chloride
Calcium carbonate
35-0
0036
23
60-0
21
Magnesium chloride ....
carbonate ....
200-0
02
400-0
Sea Water.
Sea water contains 38 parts per 1,000 of dissolved matter ;
of this from 25 to 28 parts are common salt, NaCl.
The Black Sea contains only 17-7 parts, the Caspian Sea 140,
and the Baltic 6-7, owing to the large freshwater rivers which
flow into them. The other salts of sea water are magnesium
chloride, calcium sulphate, magnesium sulphate, potassium
sulphate and chloride, bromide of soda, the carbonates of lime
and magnesia, and traces of other salts and organic substances.
Hardness.
By this term is meant 1 grain per gallon of lime carbonate,
CaC0 3 . Temporary hardness is that which can be reduced by
boiling. Permanent hardness is not reduced by boiling.
Water is softened by chemical means. 1
Pipes.
The ordinary velocity of flow in water in pipes may be taken
at 72 inches per second. This velocity is to be reduced 1 inch
per second for each 20 pounds pressure. Thus in feed pipes
at 160 pounds pressure, the velocity will be 72 8 = 64 inches.
Practical considerations demand, except where several boilers
are fed through one pipe, that the pipes should be much larger
than would give such a velocity in many cases.
1 See Water-Softening and Treatment, by the Author ; Constable &
Co. See also Liquid Fuel and its Combustion, by the Author ;
Constable & Co.
COMBUSTIBLES AND SUPPORTERS 89
Pipes less than If inches are rarely advisable for feed pipes,
and if pipes are liable to be scaled up they ought to be made
initially larger than necessary to allow of a considerable deposit
of scale without unduly diminishing their capacity.
Useful Data regarding Water.
1 gallon 10 pounds.
1 American gallon . . . 8-321 pounds.
1 cubic foot 62-2786 Ib.
1 gallon 277-479 cubic inches.
1 American gallon . . . 231 cubic inches.
1 litre 2-204 pounds.
1 foot column .... 0-434 per square inch.
1 pound per square inch . 2-304 feet head.
1 gallon 0-1606 cubic feet.
1 pound 0-01606
1 cubic foot 0-0278 ton.
1 ton 35-97 cubic feet.
(Diameter of pipe in inches) 2 Pounds per yard nearly of
water contents.
1C. per kilogram. ... 1 calorie.
1F. per pound .... 1 B.Tb.U.
Specific heat at 0C. . . 1-00.
; , Ice .... 504.
Specific gravity at 0C. . . 1-000.
Ice ... 0-922.
1 atmosphere . . . . 33-8 feet of water.
One pound of oil requires about 15 pounds of air for its
chemical combustion, or about 207 cubic feet.
Approximately this is 2,000 cubic feet of air per gallon of
oil/
CHAPTER VI
CALORIFIC AND OTHER UNITS
Thermo-Chemistry.
THE subject will only admit of slight treatment in a work
of this description. It has been exhaustively treated
by Berthelot, especially in his Thermochimie of 1897 ; therein
he gives the thermal equivalent of almost all known hydrocarbons
and other elements and compounds. When the calorific cap-
acity of a fuel is tested it will often be found to depart from
expectation. Two fuels may have the same composition, yet
produce very different effects. Thus acetylene and benzene
have exactly the same ratio of hydrogen to carbon in their
composition, their formula being C 2 H 2 and C 6 H 6 but their atoms
are differently put together, and they produce very different
amounts of heat when burned. Acetylene is very much more
endo thermic than benzene, that is to say, it actually absorbs
heat when first compounded, and this latent heat adds to its
calorific output when burned. Benzene and ethylene are
also endo thermic, but the other fuel hydrocarbons and alcohol
are exothermic, and having given out heat when formed they
give out correspondingly less when destroyed by combustion.
Thermo-chemistry teaches us to consider all substances from a
monistic point of view, seeing in every gas latent heat to
preserve it as a gas, without which heat it would fall to the state
of a liquid. Similarly, we recognize that latent heat prevents
liquids becoming solid.
We realize that the conversion of solid coal into gas, such
as occurs when coal is burned, demands an enormous heat
absorption. Thus it is that the first oxidation of solid carbon
to monoxide develops less than half the heat of the second oxi-
dation. The same or even more heat is developed by the first
oxidation, but disappears in changing the solid carbon and
solid hydrocarbons into gas. We are enabled to appreciate
the difficulties that stand in the way of perfect combustion
of bituminous fuels, when we perceive the heat absorption of
the gasification they endure before they burn. Thermo-chemis-
90
CALORIFIC AND OTHEB UNITS 91
try points out why the calorific capacity of liquid and of gaseous
fuels is better than of solid fuels ; it teaches us to study the
phenomena of specific heat, and helps us to understand and
account for an infinite variety of apparent inconsistencies
and to clear away the mists from our earlier views. As, how-
ever, in engineering we can only deal with approximations,
it is sufficient for ordinary purposes to base most calculations
on approximations, and it is useful to be able to calculate the
approximate expectation of calorific capacity of a fuel of any
type. The formula of the French chemist Dulong may still
be employed as substantially accurate. It is
Calories = a = 8,080C + 34,500(H - ) where C = weight
of carbon, H = weight of hydrogen and = weight of oxygen
in 1 kilo, of the fuel; or, if expressed in British Thermal Units,
B.Th.U. = x 14,500C + 62,100(H - f ), where x the
thermal units, C = the weight of carbon, H = the weight of
hydrogen, and = the weight of oxygen in one pound of the
fuel.
The Verein Deutscher Ingenieure use a modified formula
x = 8,100C + 29,000(H ) + 2,500S 600E, thus allow-
ing for the sulphur and for the hygroscopic water and for the
fact that the hydrogen products are produced as steam.
Mahler found an average of 44 fuels as follows
_ 8,140C + 34,500H - 3,000(0 + N)*;
100
which in B.Th.U. becomes when simplified
x = 200-5C + 675H - 5,400.
Calculation has now given way to actual measurement of a
sample in the Berthelot bomb or other form of calorimeter.
We learn from thermo-chemistry why it is that the latent
heat of steam diminishes with higher pressure, realizing that
the difference is due to the absence of performance of external
work.
A few of the leading particulars referring to the gases most
related to power engineering are re-tabulated in Table 5 from
the author's more extended table in Kempe's Year Book.
As a science thermo-chemistry recognizes no fuel as such.
It has regard merely to the heat effects of chemical combi-
nation. Combustion is usually restricted to carbon and hydro-
gen, simply because these are the two substances we find in
Nature on a sufficiently large scale to burn by means of the
atmospheric oxygen. Both produce harmless gases, namely,
steam and carbonic acid. Neither will support life, but they
are not poisonous.
92 LIQUID FUEL AND ITS APPARATUS
By aid of thermo-chemical researches we learn that the
various hydrocarbons have either absorbed or given off heat
when they combined. If the former, they are said to be endo-
thermic, if the latter exothermic. We learn to make allowance
for the different states of fuel, and to realize that a gas ought
to be superior to the same relative proportions of liquid fuel,
and this again to solid fuels. But methane, CH 4 , is a gas, and
yet it producess when burned an amount of heat less than it
ought to produce, seeing that its hydrogen is still gaseous and
its carbon is also gaseous. Instead of about 14,728 units of
heat, it produces 13,343 units only, despite the benefit of
vaporization of its carbon.
The explanation is that when its elements combined they
gave out actually more heat than was necessary to vaporize
the carbon, and the excess of heat was dissipated at the time,
and before methane can burn with oxygen, its constituents
must be separated by means of heat. The heat necessary to
do this reduces the heat of combustion. The different behaviour
of acetylene arises from its absorption of heat in formation,
such heat becoming apparent when the gas is burned.
Heat.
We do not know what heat is, but we know its effects, and we
assume it to consist in atomic or molecular vibrations.
The effects of heat, as they are apparent to our senses or to
our reasoning powers, are variously named. First may be
placed temperature. When a body is hot it can communicate
heat to bodies at a less temperature. Temperature and quan-
tity of heat have no particular relation to each other. A pound
of lead may be hotter or have a higher temperature than a pound
of iron or of water, and may be able to part with heat to those
bodies. Yet it may possess much less quantity of heat, because
lead has a lower specific heat.
The same substance in two different states at the same tem-
perature, as ice at 32 and water at 32, possesses a different
amount of heat in these two states. The difference is expressed
as latent heat, and quantity of heat generally is expressed as
units of heat, and we speak of the heat of combustion and the
mechanical equivalent of heat, and must therefore define all
these.
Temperature.
The boiling point at which the 212 of the Fahrenheit ther-
mometer is fixed is that of pure water under the mean atmo-
CALORIFIC AND OTHER UNITS 93
spheric pressure of 14-7 pounds per square inch. The Centigrade
thermometer is marked zero at the temperature of melting ice
and 100 at the boiling point, the atmosphere being the pressure
of 760 millimetres of a mercury column. Thus 1F.=$- of a
degree Centigrade. The mercury thermometer is available from
40F. to 600F., and even higher if the upper part of the tube be
filled with compressed nitrogen. For higher temperatures it is
necessary to employ pyrometers, which act by recording the
difference of expansion of diverse metals or the pressure of
heated air, or by electrical means. Metallic thermometers
are not very satisfactory. In steam engineering, temperatures
are met with from 32 to 600F. in the engine-room, from 350
to 3,000F. between the chimney and the furnace. By tem-
perature is meant that state of a body due to heat, in which
the said body can transfer heat to other bodies of less tem-
perature. Temperature is a heat effect apparent to the sense of
touch, and only by temperature can heat be transferred from
one body to another, and the transfer is always from the hotter
body to the less hot body. In this way heat can be transferred
from a body containing less actual heat to one that contains
more heat. Thus a mass of one pound of iron heated to a tem-
perature of 132F. contains 12-98 heat units. A similar mass
of water at a temperature of 82 contains 50 heat units, the
heat content being in each case measured from a datum of
32F. Yet if we immerse the iron in the water, heat will leave
the iron which contains so little heat and will enter the water
that contains so much heat, and will raise the temperature of
the water. A clear distinction must be made between tem-
perature and quantity of heat. Temperature can be measured
by a thermometer, but specific heat can only be ascertained by
equalizing the temperature of the substance whose specific
heat is sought with that of a mass of water. The final tempera-
ature enables the specific heat of the substance to be compared
with that of water.
There are three thermometric scales, namely
The Celsius or Centigrade, which divides the distance between
freezing and boiling of water at sea level into 100 degrees, the
freezing point being 0.
The Reaumur scale, still much used in Russia, divides the
same distance into 80 parts, also starting from = freezing
point of water.
The Fahrenheit scale divides the same distance into 180
parts, but starts the zero mark at 32 below freezing. Hence
the boiling point is 212. It is frequently necessary to con-
vert one reading to another. The following are the formulae
94 LIQUID FUEL AND ITS APPARATUS
for doing so, C., R. and F. being the respective readings on
each scale.
To convert C. to R.
C. x | = R.
To convert R. to C.
R. x = C.
To convert C. to F.
(C. X f ) + 32 = F.
To convert F. to C.
(F. - 32) x f = C.
To convert F. to R.
(F. - 32) x | - R.
To convert R. to F.
(R. x f ) + 32 = F.
It is particularly necessary not to forget the addition or sub-
traction of the 32 of the Fahrenheit freezing point when con-
verting temperatures, but it is also necessary to remember not
to do so when converting mere statements of differences of
temperature. Thus if water is cooled 50C., this means it has
been cooled through 90F., not through 90 + 32. This point is
often confused by writers and leads to very erroneous statistics.
By temperature we thus understand that a body in a certain
state is in a certain condition of molecular vibration. Different
bodies are differently affected by heat. Some bodies are placed
in the state of molecular vibration known as temperature with
less heat than others. Thus water requires more heat than
any other substance, excepting only hydrogen. The relative
amounts of heat to place bodies in a given state of vibration are
called their capacity for heat or specific heat.
In Table VI are given a few characteristic temperatures.
Furnace temperatures can now be measured by the Fery
radiation pyrometer. This instrument is stood at any con-
venient and comfortable distance from the furnace, and the
hottest of furnaces may thus easily be measured. The in-
strument is not exposed to high temperature, though it measures
this from its distant standpoint. It can be obtained, with
explanation of use, from the Cambridge Scientific Instrument Co.
Specific Heat.
By specific heat is meant the number of heat units necessary
to raise 1 pound of a substance 1 Fahrenheit, and as water
has the highest specific heat of any solid or liquid, it is taken
as the basis. The specific heat of water is measured at the
temperature of maximum density, 39-lF., by some writers,
CALORIFIC AND OTHER UNITS 95
including Rankine, but 32 is probably more usual. The
difference is unimportant. The specific heat of all bodies
increases slightly with increase of temperature, a fact due to
the increased molecular movement, and there is often very
considerable difference between the specific heat of the same
body solid and liquid, notably in the case of water, the specific
heat of ice being only 0-504.
Since 1 pound of water requires 1 unit of heat to raise its
temperature 1, its specific heat is thus said to be unity. All
other substances are referred to water as a basis. Thus when
we say that lead has a specific heat of 0-0314, we mean that to
heat a pound of lead to a certain temperature only requires
about 3 per cent, of the amount expressed in B.Th.U. that
would be required to raise the temperature of an equal weight
of water by the same amount. It is necessary to know the
value of the specific heats of brick, iron, fuel and its products,
in order to calculate pyrometric effects, furnace temperatures,
etc. For the purpose Table VII of specific heats will usually
serve. More extended tables are found in most pocket-books.
Gases have two specific heats ; that at constant volume
and that at constant pressure, the latter being greater and due
to the work done in expanding to constant pressure. Table VII
gives the specific heat of the more usual gases met with in
combustion.
The specific heat of all substances appears to increase with
heat, more especially in the case of the gases. This is not of
much importance in boiler work, but is considerable in gas
engine research. In high temperature work the increase
must be considered, but no error is introduced by neglecting
the change when results are finally stated at low temperatures.
The increase of specific heat with temperature is most marked
in the case of the more easily liquefied gases.
Specific heat, then, is the relative amount of heat necessary
to give to bodies a given temperature. The specific heat of
other bodies is stated as the fraction of unity relative to water.
Most substances about a furnace, as fire-brick, have a specific
heat of about 0-2. The total heat in a body is the product of
its mass, its temperature and its specific heat as compared
with some substance at another temperature and in the same
state physically. Thus ice, water and steam which are
chemically identical, differ in their physical states and cannot
be so compared. The specific heat of ice is only about 0-504, and
that of steam is 0480. Ice at 32F. may have heat added to it
until it becomes water at 32F.
Water at 212F. will absorb heat and become steam at 212F.
96
LIQUID FUEL AND ITS APPARATUS
In both these cases we see no change of temperature due to the
additional heat, but we see a change of physical condition.
One pound of ice has absorbed 142 B.Th.U. of heat to enable
it to exist as water. Any further heat then added will increase
the temperature until 212F. is reached. Then we may add
966-7 B.Th.U. to the water with no change of temperature,
but we get the water in the still higher physical state of steam.
In each case the heat has become hidden or latent. It is not
apparent as temperature, but is occupied in keeping the molecule
liquid or gaseous, as the case may be. Heat which thus disap-
pears in changing the state of a body is termed latent heat.
Latent Heat.
Latent heat is thus the heat enquivalent of the changed
state of a body. It is not stated, however, as is specific heat,
in terms of the ratio to water, but in actual heat units per unit
of weight, as in calories per kilogram or B.Th.U. per pound.
Thus the latent heat of water is said to be 142-6, because the
melting of 1 pound of ice demands 142-6 B.Th.U. It is impor-
tant to know the latent heat of a few substances. Some are
given in the table below, those marked * being hypothetical
and not definitely determined.
Per Pound.
Per Kilo.
B.Th.U.
Cal.
Cal.
B.Th.U.
Ice to water, both at 32F . .
Water to steam, 212F. . . .
Carbon to gas
142-6
966
5,817
444
7,320
521
6,900
35-93
243-3
1,466
111-9
1,845
131-3
1,739
792
536-4
3,231
246-7
4,066
289-4
3,833
314-3
2,128
1,282
978-4
16,130
1,148
15,210
Oxvseii to eras * .
Hydrogen to gas * . . . .
Nitrogen to gas *
Water to gas (H 2 O dissociated) 1
Heat becomes latent not merely by such a process as actual
boiling of water. It becomes latent equally when water is
converted to vapour by absorption in dry air : the heat must
come from somewhere in such a case, and it comes primarily
from the air or from the wooden floor on which water has been
sprinkled for cooling purposes. If steam be heated above its
saturation temperature, it will now only absorb about 0-480
of a unit. Hence the specific heat of steam is barely half that
of liquid water. After a very considerable further addition
of heat, a point is reached where the temperature again ceases
to rise ; but again here is a change of state. The water is
solid condition in coal.
CALORIFIC AND OTHER UNITS 97
split up into constituent elements of oxygen and hydrogen,
and one pound of steam will absorb 6,900 thermal units during
the splitting up of its chemical affinities, showing the great
energy of chemical changes, for to melt ice requires 142 heat
units per pound ; to vaporize the water requires 966-7 heat
units, and to decompose it demands 6,900. No matter how
it occurs that a body change its state, heat is given out or
absorbed. To set free the solid hydrogen or solid water locked
up in a piece of coal demands heat which is rendered latent.
Thus heat is rendered latent when carbon is vaporized, and
when again carbon is reduced from its state of carbonic acid gas
to the solid form of wood by the action of the living forces of a
tree, the heat is again set free by the solidification of the carbon ;
but the heat rendered latent in the decomposition of a body
is known as the heat of dissociation, and, like latent heat, is
expressed in actual heat units.
Dissociation.
The heat absorbed in any process of chemical dissociation
is an exact equivalent of the heat which is set free when the
same substances combine. Thus if 1 pound of hydrogen unite
with 8 pounds of oxygen to produce 9 pounds of water, the
heat of combination is 62,100 B.Th.U., and therefore the heat
of dissociation of water is 62,100 -^- 9 = 6,900 B.Th.U.
There now remains to consider only the
Unit of Heat.
The unit of heat is merely an arbitrary measure of comparison.
In British measures it is the amount of heat necessary to raise
the temperature of 1 pound of water through 1F. at or near
32F.
In the metric system it is the amount of heat necessary to
raise the temperature of 1 kilogram of water through 1C.
As 1 kilogram =2-204 pounds and 1C. =F. the ratio of
the two units is 2-204 x 9 -^ 5 = 3-968, the reciprocal of which
is 0-252.
The British Thermal Unit is written B.Th.U., and the metric
unit is called the calorie and is written cal. Therefore 1 cal.
3-968 B. Th.U., and 1 B.Th.U.= 0-252 cal. For near approxi-
mation the ratio of 4 : 1 may be employed.
The heat unit is employed to express latent heat of com-
bustion or of dissociation.
It is necessary to have a statement of the relation of the heat
form of energy and the unit of mechanical work.
G
98 LIQUID FUEL AND ITS APPARATUS
Unit of Work.
The unit of work is expressed in the form of the earth's
attraction.
For the purpose of the engineer the attraction of the earth
is measured by the pull exerted at sea level in the latitude of
London upon a piece of metal which is called the pound. The
work done in lifting one pound through a height of one foot is a
unit of work and is called the foot pound. Heat and mechanical
work are mutually convertible. Dr. Joule, of Manchester, by
the agitation of water by means of falling weights, ascertained
that the unit of heat or B.Th.U. is the equivalent of 772 pounds
raised one foot, or 772 foot pounds at the latitude and elevation
of Manchester, and, with very slight variation, of no account in
engineering, at any spot on the earth's surface. Joules' deter-
mination of 772 was made by means of thermometers less
perfect than those now procurable, or his figure would have
been 778 foot pounds, as since found by Rowland.
The mechanical equivalent of 772 foot pounds per degree
Fahrenheit becomes 1,389*6 foot pounds per degree Centigrade.
Expressed in terms metrical altogether or in kilogram
Centigrade units, the equivalent is 3,063-54 foot pounds or
423-55 kilogram metres.
Thus the calorie is 423-55 km. = 3-968 B.Th.U.
With the more modern figure of 778 foot pounds = 1 B.Th.U.
=3,087-3 foot pounds. Per calorie = 426-84 kilogram metres,
so that 1 B.Th.U. =107-78 metre kilograms.
Weight.
Like the British pound, the kilogram is simply a piece of
metal, and work units are done in raising it against the pull of
gravity. Hence the kilogram metre, whose relation to the foot
pound is 7-231 : 1.
The kilogram is 2-2 pounds (actually 2-2046212). The pound
is thus 0-4536 kilos.
The metre or unit of length is 39 370432 inches, or say 3 feet
3 inches, and f- very nearly for easy remembrance and mental
calculation.
Errors in converting units are most likely to occur when units
are compound, as when converting pounds per square inch to
kilos per cm. 2
Very closely the English ton of 2,240 pounds resembles the
French tonne of 1,000 k. =2,204-6 pounds.
Also 1 k. per linear metre is equal nearly to 2 pounds per
linear yard, and 9 calories per cubic metre is very closely
1 B.Th.U. per cubic foot.
CALORIFIC AND OTHER UNITS 99
Gravity.
Gravity G at Greenwich is 32-19078 feet per second
acceleration per second, usually written 32-2 per sec 2 .
The expression <\/2G may be approximated as 8.
Metrically, G = 9 8117 metres per second 2 at Greenwich.
The true value at any other latitude (L), in centimetres per
second 2 is
980-6056-2-5028 Cos 2 (L)- 0-000003 H,
where H is the height above sea level in centimetres.
Other compound units that are useful are as follows
1 B.Th.U. per sq. ft. = 2-713 cal. per square metre.
1 ,, ,, pound = 0-556 cal. per kilogram.
To find the number of cubic feet of air at 62F. chemically
consumed for one pound of fuel, take the percentage of carbon,
hydrogen and oxygen in fuel. To the carbon add three times
the hydrogen and subtract four- tenths of the oxygen and
multiply the remainder by 1-52. The product is the cubic
feet of air (A).
Thus A =1-52(0 + 3H-0-4 0).
The weight of air per cubic foot is - pounds, or 13' 14 cubic
lo' 14
feet= 1 Ib.
The total weight of gaseous products per pound of fuel is
found by multiplying the percentage of carbon by 0-126 and
that of the hydrogen by 0-358. The sum gives the total gases
(W), thus W =0-126 + 0-358 H.
The total volume is found by multiplying the carbon
percentage by 1-52 and the hydrogen by 5 52 ; the sum of
these is the total volume (V) in cubic feet at 62F., thus
V:= 1-520 + 5-52 H.
The volume at any other temperature (T) is V 7 =
v T + 461
523
THE CALORIFIC POWER OF FUEL.
Calorific Formula.
Dulong and Petit and subsequently Favre and Silbermann
determined the calorific capacity or heat of combustion of
many substances with more or less accuracy. Dulong endea-
voured to find a formula for calculating the heat of combustion
of any fuel of which the chemical composition was known.
100 LIQUID FUEL AND ITS APPARATUS
The capacity given by him to carbon was 7,295 calories. The
latest determination of Berthelot is 8,137 and that for hyd-
rogen is 34,500.
Dulong's formula for fuel according to its composition is,
with the correction to modern coefficients
Cal. =8,137 C + 34,500 (H-f) where
C is the carbon in 1 kilogram of fuel, and H and are the
hydrogen and oxygen respectively, it being assumed that the
oxygen is already combined with hydrogen and that so much
of the hydrogen is already useless. Any error would appear
to be on the safe side, and the formula assumes the return of
all the gases to 0C.
In actual practice, the gases pass at a temperature of over
100C., and the water is in the form of vapour, and the calorific
capacity of hydrogen is often taken as only 29,150 B.Th.U., to
allow for the heat absorbed in vaporization of the water.
In Germany, Dulong's formula is thus used in the form
Cal. = 8,100 C + 29,000 (H-f) + 2,500S-600W,
where S is the sulphur present, and W is the weight of hygro-
scopic water.
Seeing that in coal the hydrogen is as solid apparently as the
carbon, it appears correct to take something off the co-efficient
of hydrogen to allow for the heat absorbed in gasifying it, and
in the above formula the subtraction of 150 calories perhaps
helps to make this formula coincide very closely with calori-
metric results.
Possibly also the rounding off of the co-efficient for carbon
from 8,137 to 8,100 helps to correct for the vaporization of the
carbon compounds which are exothermic when first formed,
and do not give up the full heat value of their separate hydrogen
and carbon. Both marsh gas, CH 4 , and ethane, C 2 H 6 , give
out heat when formed and require it again when dissociated,
and coal is so complex a body, as are also liquid fuels, that very
little positive knowledge can be assumed : it is sufficient to
know that the formula last given is a very fair approximation
to the truth.
The Calculation of Temperatures.
The temperature of combustion of any substances depends
upon the calorific capacity of the burning material, the total
weights of the products formed, and the specific heat of the
products. The calculation of the theoretical temperature is
therefore simple.
CALORIFIC AND OTHEIt, UNITS^?
The specific heat of all bodies, and particularly of gases,
increases with temperature, and this reduces the temperature
actually obtained. Though hydrogen has so high a calorific
capacity, it does not produce a specially high temperature as
compared with carbon, for in the first place it demands 8 times
its own weight of oxygen, and secondly the specific heat of the
product, steam gas, is also high, viz., 0479.
The calculation of temperature for hydrogen burned with
oxygen is
T = 9
These are temperatures very much in excess of anything
secured in the laboratory, which has not reached 3,000C.
(even under a pressure of 10 atmospheres).
With air, however, the oxygen is accompanied by a weight
of nitrogen 3-32 times its own weight, and to burn 1 unit of
hydrogen requires 8 pounds of oxygen and 26-56 of nitrogen,
the specific heat of which is 0-244. The calculation for tem-
perature is thus
T = (9 x 0479) +6 56 x 0-244) = 2 > 513 * C ' = 4 ' 554 F '
The calculation for carbon turned to carbonic oxide is similarly
derived from the heat capacity =2,453 cal. The oxygen
necessary is 1J times the weight of the carbon consumed, and
as the calorific effect of the first oxidation of carbon is 2,453
calories per kilogram, we obtain
when burned with oxygen, the total product being 2-33 k. of
carbonic oxide of 0-245 sp. heat. Then, with air containing
3 32 times as much nitrogen as oxygen, we have
r _ 2,453 _
"(2-333 X 0-245) + (1-333 X 3-32 X 0-244)
= 2,705F.
Where the amount of air is in excess of the chemical minimum,
a further term must be inserted in the denominator ; as neither
the nitrogen nor the oxygen of the excess air is altered, they
may be considered together. The sp.heat of air is 0-237, and
the weight per unit of fuel being W, we have the new term
in the denominator (W X 237), and the temperature of the
final product is reduced simply because of the greater weight
of final gases over which the heat generated per unit of fuel is
102 LIQUID FUEL AND ITS APPARATUS
distributed. In Table V are given the calorific capacities
of the various forms of carbon and of hydrogen, together with
the resulting temperatures of combustion with a minimum
of oxygen or equivalent air. The values are given per gram,
litre, pound and cubic foot for combustion to carbonic oxide
= CO and to carbonic acid = C0 2 for carbon, and to water
(vapour) and water (liquid) for hydrogen.
These temperatures are not attained in practice. St. Glair
Deville considers that they are prevented from occurring by
the dissociation which is said to occur at high temperatures.
A certain temperature is attained and further combustion
ceases until some of the heat has been dispersed, when further
combustion proceeds. Berthelot, while not ignoring dis-
sociation, is rather of the opinion that the inability to attain
theoretical temperature arises from the proved increase of the
specific heat of all bodies, and especially of gases at high tem-
peratures. Probably both causes have effect.
With liquid fuels, which contain so much hydrogen, the
calorific capacity of the hydrogen cannot exceed 29,100 cals.
or 52,290 B.Th.U., because the aqueous vapour always passes
away as vapour.
One pound of water vapour contains
1,091-7 + 0-305 (T - 32) B.Th.U., where T is the temperature
Fahrenheit.
Similarly where T is the temperature Centigrade 1 kilogram
contains 606-5 -j- 0-305 T calories, whence can be calculated
the heat lost where saturated steam is thrown away. But in a
furnace the waste gases are much above saturation temperature,
and all vapour above 212F. must be calculated to absorb at
least 0-480 of a thermal unit or calorie per pound or per kilo-
gram for each degree Fahrenheit or Centigrade beyond 212F.
or 100C. respectively.
In calculating furnace temperatures there must always be
added the temperature of the atmosphere to the calculated
temperature, which is based on the datum of 0C. The usual
atmospheric temperature is 15C. = 60F. for convenience, a
sufficient approximation. The total amount of water to be
allowed for in any fuel sample is nine times the weight of
hydrogen in the sample plus all the water. Water should be
nil with liquid fuel warmed sufficiently to cause the water to
separate.
In calculations of the hydrocarbon gases the figures given
above are combined ; thus for benzene, C 6 H 6 , the calorific
capacity is 10,052 from the gas or 9,960 cal. from the liquid.
CALORIFIC AND OTHER UNITS 103
This substance requires in all 3-077 times its weight of oxygen,
and produces 3-385 parts of CO 2 and 0-6923 of H 2 0, or 4-077 in
all.
The calculation for temperature is therefore
9 960
(0-0923 x 0479)"+ (3-385 x 0-217) =
when burned in oxygen.
With air there is an added weight of nitrogen equal to 3-077
X 3-32, the specific heat of which is 0-244.
This product, 3-077 x 3-32 x 0-244 is added in the denomi-
nator, and the resulting temperature is found to be 2,798C.
Any excess of air above that chemically necessary is then
allowed for by means of the extra term in the denominator
(W X 0-237), as above explained.
Relative Volume of Gases produced by Combustion.
When a fuel contains carbon only the volume of the gases
produced by perfect combustion is identical with the air ad-
mitted to the furnace, for in producing carbon dioxide two
volumes of oxygen produce two volumes of carbonic acid, or
C x 2 = C0 2 , which, like almost all compound gas, occupies
two volumes.
When combustion is imperfect and carbonic oxide is formed,
the result is C + O CO, or two volumes from only one
volume of oxygen, and the waste gases exceed the volume of
air supplied.
Sulphur in a fuel leads to no change in volume. Hydrogen,
2 volumes, forms with 1 volume of oxygen 2 volumes of gas,
or H 2 + O = H 2 O=2 volumes of water vapour. But when flue
gases are collected the water vapour condenses and there is a
diminution of volume.
Each unit of hydrogen in fuel requires 8 units of oxygen.
Expressed metrically, 1 gram of hydrogen will consume 8
grams of oxygen. As oxygen weights 1-43 grams per litre,
each 1 gram of hydrogen will cause to disappear 5-6 litres of
oxygen or nearly 0-2 cubic feet.
This volume disappears and the total volume of gases must
be increased by the addition of the volume of oxygen destroyed
by hydrogen.
Though not of much account in respect of coal, the large
percentage of hydrogen in liquid fuel renders the waste gases,
when cooled, very much less in volume than the original volume
of air. Thus an ordinary oil may contain 12 per cent, of
104 LIQUID FUEL AND ITS APPARATUS
hydrogen, or 120 grams per kilogram. This will destroy 960
grams of oxygen or 672 litres for each kilogram of liquid fuel.
In calculating the percentages of the total gases this volume
of vapour must be allowed for. Per pound of fuel containing
say 12 J per cent, of hydrogen exactly one pound of oxygen
will be used measuring 11-2 cubic feet. Thus should the
apparent volume of air be 260 cubic feet, the actual volume
would be 271-2.
The Table of gases (V) will be useful in such calculations.
Evaporative Power of Fuel.
The evaporative power of fuel is usually stated in terms of
the water evaporated from and at, 100C.=212F., at which
temperature all the added heat becomes latent and disappears
at the rate of 537 calories per kilogram of water, or 966' 7
B.Th.U. per pound. The theoretical duty is thus obtained
by dividing the calorific power of the fuel by these numbers
Hydrogen should evaporate ' = 54*28 times its weight
OO i
8 137
of water. Carbon should evaporate ' = 15-15 times, and
the best coals have a capacity of about 15 J times, the highest
values corresponding with the highest proportion of hydrogen
when this is not neutralized by being already in combination
with oxygen. Liquid fuel may run as high as 22 evaporation.
The actual evaporation secured will fall short of the theoreti-
cal by 15 per cent, in the very best exceptional cases to 30 per
cent, in good but heavily worked boilers, the results obtained
depending upon the perfection of combustion, the avoidance
of excessive air and the proportions and condition of the boiler.
A good result with coal is 10J, which corresponds with about
15 for good liquid fuel. Coal often falls as low as 8 and liquid
fuel as low as 12.
Reference is made elsewhere to the supposed superior effici-
ency of liquid fuel as compared with solid fuel, in regard to the
fact that Nature has supplied the latent heat of liquidity, but
it is also shown that probably the effect is small, the latent
heat of liquidity being only a fraction of that of vaporization.
Gaseous fuels, therefore, should be expected to give higher
values than liquid fuels. The formulae for calculating the
calorific effect of a fuel give a result greater than the actual
calorimetric values of hydrogen and carbon. In a liquid fuel
the carbon should give more than its nominal solid rating, but,
on the other ha.nd, the rating of hydrogen at 29,150 cals. is
CALORIFIC AND OTHER UNITS 106
obtained from hydrogen gas, and, in a liquid fuel, the hydrogen
has been deprived of its latent heat of gasification, and by
so much must lose effect when burned, and, per pound, the
hydrogen loses much more than is gained per pound of carbon.
Solid fuels, of course, lose still more, but the difference between
liquid and solid fuels is not very great in respect of their differ-
ence of physical condition. Where liquid fuel secures its high
calorific value is in its very high percentage of hydrogen, and
its freedom from oxygen and ash. The absence of oxygen is
a proof of the full efficiency of the hydrogen, except so far,
of course, that the hydrogen is combined with the carbon and
the combination when effected was exothermic.
As a sample of liquid fuel calculation, a petroleum may be
taken, such as a heavy Baku oil, with 87*0 per cent, of carbon
and 13 per cent, of hydrogen. The excess of air will be assumed
to be 50 per cent, beyond theoretical requirements. The oil
was tested to give 10,843 calories by Mahler.
Calculated by the improved Dulong formula we have
Cal. = (8,100 X 0-87) + (29,000 x 0-13) = 10,817 cal.
which corresponds very closely with the calorimetric test.
Had the full values of 8,137 and 29,150 been employed, the
result would have been slightly above the actual finding, and
for a very pure hydrocarbon it is probable that calculation and
tests will not prove to be far apart.
The temperature secured by this oil with the 50 per cent.
air excess will be
_ 10,817 __ _
(87 X 3-66 X 0-217) + (-13x9 X 0-479) + (3'36 X 3'32
X 0-244) + (5-575x0-237).
In the formula the first term of the denominator gives the
heat absorbed by the C0 2 formed from 0-87 of carbon, and the
oxygen consumed is 0-87 = 2-66 = 2-32. The second term
gives the heat absorbed by the steam produced from 0-13 of
hydrogen, and the oxygen consumed is 0-13 = 8 x 1*04. The
third term gives the heat in the nitrogen which accompanies
the consumed 3'36 of oxygen.
The total weight of air used is thus 3*36 + (3-36 x 3-32)
=11-15. Then 50 per cent, of this, or 5-575, is put into the
fourth term with the specific heat co-efficient of air. Working
out, the result is
10817
as the theoretical temperature of the fuel when supplied with
106 LIQUID FUEL AND ITS APPARATUS
50 per cent, excess of air. This shows how temperature is
reduced by excessive air. Granted that this temperature is
more than would actually be attained owing to the rise of the
specific heat of gases with the temperature, the fact remains
that the furnace temperature would be more nearly maintained
along the flues. The absorption of heat by the boiler, lowering
the temperature, would set free the heat which has become
latent under the term specific heat, and the curve of tempera-
ture drop would be less steep.
But beyond all this there is a final chimney temperature
beyond which it is not commercially practicable to reduce the
gases, and if by using too much air we double the weight of
rejected gases, these, at a given temperature, will carry off
just twice as much heat as would be carried off by half the
weight. Thus, if the chimney temperature is 950F. or 400
above the atmospheric temperature, each pound of gas runs
away with approximately 400 x 0-237 B.Th.U.=94'8 B.Th.U.,
which is about 1,560 B.Th.U. per pound of carbon fuel burned
or approximately 9 per cent, of the heat, on the assumption
that the chemical minimum of air has been used. But had the
air supply been doubled the heat thrown away would have
been doubled also, and a loss of about 18 per cent, would have
been incurred.
Excepting that it is important to have clear ideas upon the
effect of air supply, it does not much concern the engineer
to know what theoretical temperatures are secured, though he
must be on his guard against unduly low temperatures in the
furnace, and be prepared to guard against this by proper design,
such as keeping heat-absorbing surface away from the gases
until combustion is sufficiently perfect to enable this to be done,
The engineer is usually concerned with the evaporative
efficiency of a fuel, and calculates this from and at the boiling
point of 100C. = 212F. The heat of evaporation of a kilo-
gram of water is 536-5 cals. or 965*7 B.Th.U. per pound. The
evaporative power of a fuel is therefore to be directly obtained
by dividing its unit calorific capacity by the heat of vaporiza-
tion of water from and at 100C.
For pure carbon the figure obtained is
H 1 ^17
E = 21 = 15-165, or, in British figures,
'o
the slight discrepancy being due to errors in the equivalents
for want of unimportant decimals.
CALORIFIC AND OTHER UNITS 107
The actual evaporation of a steam boiler neve;- approaches
the calculated figure within 20 per cent. This 20 per cent, of
loss of effect is due to several causes
(1) The whole of the fuel is not burned perfectly.
(2) The waste gases are sent away to the chimney at a
temperature considerably above that of the atmo-
sphere at which the fuel and air is supplied.
(3) There is a large excess of air in the waste gases.
(4) Much heat is lost by radiation from the boiler and
brickwork ; and, with solid fuels, in ashes and
clinkers.
M. Clavenad has a peculiar method of calculating calorific
capacities. He points out that the figures of 8,000 and 34,500
for the solid and gaseous states of carbon and hydrogen re-
spectively are incorrect for liquid hydrocarbons. The heat
disengaged by gaseous carbon when burned is equal to that
disengaged by four atoms of hydrogen gas.
The atomic weight of carbon being 12, and one kilogram of
hydrogen having a power of 34,500 calories, then 1 kilo of
carbon in a gaseous hydrocarbon will possess
calories.
In the complete combustion of carbon the first reaction,
C + = CO, produces as much heat as the second, CO + O
C0 2 . The weight of carbon in one kilo of CO being 0-428 kilo,
and the combustion of this from CO to CO 2 producing 2,431
calories, therefore 1 kilo of carbon completely burned must
produce
= 11,360 calories.
Hence M. Clavenad takes the calorific power of gaseous
hydrocarbon as 11,500 or 11,360 for the carbon, and 34,500
for the hydrogen, figures which, however, will not fit with
actual determination, because of the disturbing effects of
exothermism, as in the case of marsh gas, CH 4 , which falls
much short of calculation.
Mahler has shown in the table below that the calculated
calorific capacity on the assumption of H = 34,511 and C =
7,860 is greater than experiment shows to be the case.
The difference P p is less for crude oil than for products
industrially produced. The calorific power of the various oils
studied ranges from 10,300 calories for crude Russian to 11,100
for American crude.
108 LIQUID FUEL AND ITS APPARATUS
According to Colomer and Lordier, the relative weights of
different fuels to give equal evaporation are
Petroleum residue 100
Peat 320
Coke 142
Good coal briquettes 140
Anthracite (Donetz) 139
Coal . . 153
Moscow Basin 276
Ural Basin 176
Kauban Basin 140
Poland 165
Silesia 167
English 139
Goutal's formula for calculating the calorific value of fuel
from its composition is
P = 82 C + aV ; where
P = calorific power in calories.
C percentage of fixed carbon.
V = percentage of volatile matter.
a = a variable co-efficient depending on the amount of
ash and water in the fuel.
Using the formula
_V X 100
c + v
the following values are obtained for (a).
V'= 5, 10, 15, 20, 25, 30, 35, 38, 40.
a .= 145, 130, 117, 109, 103, 98, 94, 85, 80.
This formula is applicable to solid fuels.
SMOKE AND COMBUSTION.
The Combustion of Hydrocarbons.
When hydrocarbon fuels are burned there may be formed
smoke of two distinct varieties. The first is the greenish-
yellow fume which is driven off coal when placed upon a fire.
This fume is simply hydrocarbon gas with its contained tars,
and can be burned. It is the usual smoke produced by the
domestic fireplace, and burns freely when an under fire be-
comes hot and the gases are once fairly alight.
The other variety of smoke is the black smoke which deposits
soot. Soot is a flocculent variety of carbon which is produced
by the sudden cooling of heated hydrocarbon gases. In the
furnace of a boiler wherein the green gases are well ignited
they are allowed to come into contact with the cold surfaces
CALORIFIC AND OTHER UNITS
109
s
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r-H <M
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oooooooooooot^oo
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110 LIQUID FUEL AND ITS APPARATUS
of the boiler, and soot is formed. Had the green gases been
supplied with air intimately mixed, they would have burned
completely with no smoke, if they were not cooled down by
the boiler. When a boiler furnace is of correct form, the
combustion of the hydrocarbon gases can be secured when a
proper admixture of air is carried out, and in the Lancashire,
Cornish, and other shell boilers, smokeless combustion can be
approximated if the draught is good. The means of admitting
air is usually a grid in the furnace door. The air thus admitted
sweeps over the whole surface of the fire and becomes blended
with the gases given off the green coal, and perfect combustion
will take place if there is sufficient free space beyond the bridge
in which flame can burn unhindered by cold water pipes.
If, however, the draught is poor, the air drawn in over the
fire through the door will be insufficient, and smoke will be
produced. About 3 to 4 square inches of air openings are neces-
sary for each square foot of grate surface.
When insufficient draught is due to the smallness of the
chimney or flues, or to bad brickwork, it can be remedied by
repairs, or by the use of a small steam jet, to induce a flow of
air through the door grid.
If the poor draught is due to the necessity of closing the
dampers to moderate the intensity of the fires, it is then neces-
sary to reduce the area of the fire-grate, so that the chimney
draught may be made more intense on the smaller area, the
damper being kept open. This keeps up the draught suffi-
ciently to compel the air to flow in at the door grids in ample
volume. The same effect may sometimes be secured by fitting
dampers to the ash-pit opening, so as to control the intensity
of the fires even with a full open chimney damper. The full
draught power then remains available to draw in air through
the door grids to burn the hydrocarbon gases above the fire.
Any draught less than J-inch water-gauge, or say a velocity of
30 feet per second, will usually make it impossible to burn coal
without smoke.
In no case can smoke be prevented where the gases rise verti-
cally from the fire and pass directly between the tubes of a
water-tube boiler, for the necessary mixture of air has not been
secured. Belleville tried to effect a mixture by blowing high-
pressure air jets into the furnace in order to mix up the gases,
but the method is faulty, and cannot be a success where the
tubes are so close above. The same principles apply to the
combustion of liquid fuel, with certain differences due to the
method of firing. With liquid fuel the supply of gas is uniform
and continuous, and the fuel is supplied in exceedingly small
CALORIFIC AND OTHER UNITS 111
particles intimately mixed with air to begin with, and supplied
with a further volume of air from below. A uniform high
temperature is maintained in the locus of combustion by a
sufficient mass of fire-brick work in the form of arches or chequer
work.
The production of soot is well illustrated by the system of
manufacture of lamp-black, which is carried on by burning a
large number of oil lamps in a confined space with an insufficient
supply of air at a low temperature. Soot is thus formed, not
alone by cooling heated hydrocarbon gas, but by attempting
to burn it with an insufficient air supply.
Oil fuel will produce dense smoke when not supplied with
sufficient air, but in all the approved methods of combustion
the requisite air is supplied, and can be regulated very exactly.
Combustion also takes place at a high temperature, and the
flame produced is comparatively short, and combustion can be
completed in a comparatively restricted space, as in the firebox
of a locomotive, which can be perfectly fired by oil fuel without
any change from the conditions found necessary with coal. All
manner of contrivances have been patented for the prevention
of smoke, but few, if any, have realized the all-important detail
of temperature, for without sufficient temperature in addition
to the proper mixture of air in a furnace of correct form, there
can be no perfect combustion.
All smoke troubles may be attributed in general terms to the
too early application of the heat absorbing surfaces of the boiler
to the yet unconsumed gases. While the foregoing arguments
apply more particularly to coal, their principles are equally
applicable to oil. Anthracite coal, which contains no hydro-
carbons, burns away altogether at the grate surface with an
intensity of temperature very much in excess of that of any
bituminous coal.
The latter must be distilled on the grate, and much heat is
absorbed in the gasification of the hydrocarbons. The zone
of combustion is very much extended, the temperature at the
grate is less, arid it is necessary to conserve the heat generated
on the grate in order to keep hot the hydrocarbon gases, so
that these also may burn and not be wasted. With liquid fuel
the gasification is already partially effected, and combustion
is rendered more perfect by heating the liquid and also heating
the air by which it is atomized. Thus, if the oil and air be both
heated to 200F., the temperature of combustion will be higher
by about 150F. than if both oil and air were supplied at the
ordinary atmospheric temperature. The following extract
from the Author's paper on the subject of hydrocarbon com-
112 LIQUID FUEL AND ITS APPARATUS
bustion in the Electrical Review, of August 30, 1901, may be of in-
terest in this connexion with the subject of furnace temperatures.
Furnace Temperatures.
An argument in favour of the necessity of refractory furnaces
for bituminous fuel is that only a proportion of the total calorific
capacity of a bituminous coal is generated on the grate, and
therefore the fuel which burns on the grate is debited, not only
with its own combustion, but also with the splitting up of the
hydrocarbons and other volatiles, and raising them to such
temperatures as will enable them to burn at a second zone of
combustion.
An average of 18 analyses of Newcastle coal gives the follow-
ing figures-
Fixed carbon 48-84 per cent.
Volatile carbon 33-29
Hydrogen 5-31
Oxygen . 5-69
Nitrogen 1-35
Sulphur 11-24
Ash 3-77
Calorific capacity 15,203 B.Th.U.
The calorific capacity of amorphous carbon is about 14,647
B.Th.U. per pound ; therefore the capacity of the 48-84 per
cent, of fixed carbon in the above samples must be 7,150 B.Th.U.
As regards the fire upon the grate, these 7,150 heat-units are
all we have to work with. We have to draw on them for the
heat which becomes latent in converting the solid coal to the
gaseous hydrocarbon. A piece of coal is all solid, and except-
ing the ash, it all becomes gaseous. Subtracting for cinders
3-77 per cent., there remains 47-0 per cent, of volatile solid
matter, which ultimately passes off in a gaseous state. The
customary allowance of air is about 18 pounds per pound of
coal. This also must be heated up to the general temperature
by the heat developed on the grate by the fixed carbon only.
The theoretical flame temperature of carbon when burned in
an exact sufficiency of air (i.e. 11 J pounds per pound) is 4,892F.
We can readily calculate the net temperature of all the products
in the usual manner, though the result will be approximate
only. We may assume 1 pound of coal, and we will add the
customary 18 pounds of air, so as to produce a final 19 pounds
of the total furnace products. As the temperature of combus-
tion of carbon in air is 4,892F., when using 11-6 times its
weight in air, the temperature with 18 pounds of air will be
12 6
-- x 4,892 = 3,245I\ But with the heat produced by
CALORIFIC AND OTHER UNITS 113
48-84 per cent, of the coal, we have to carry the further load of
volatile fuel and inert ash that is not burned on the grate,
together with its similar proportion of excess air. The
temperature of 3,245F. x -4884 = 1,584F., and this is the
maximum temperature of the products of combustion, assum-
ing that they escape uncooled. This is a maximum figure,
because whereas the temperature of combustion in air, namely
4,892, is that due to a minimum of air, the reduced tempera-
ture involved by the use of excess of air as above calculated is
really too great in part proportion as the specific heat of nitro-
gen is greater than that of carbonic acid ; nitrogen, of course,
forms by far the greater proportion of the furnace products,
and it has a specific heat of 0-244, as compared with carbonic
acid 0-217. Steam also, which is formed on the grate and
does its share in reducing the temperature, has the high specific
heat of 0-480, any free hydrogen that may escape has 3-410,
and the hydrocarbons have also very high specific heats, for
example, olefiant gas, 0-418 ; marsh gas, 0-593.
It is thus clear that the temperature of the gases as they
flow to the bridge is quite low, and so far no deduction has
been suggested for the vaporization of fully half the solid fuel
into gaseous form. What, in fact, is the effect of the latent heat
of evaporating carbon, hydrogen, oxygen, from the solid ? for
this is really what happens when bituminous coal is burned.
To evaporate carbon requires 5,817 British Thermal Units
per pound, this being the difference between the calorific capa-
city of carbon burned to its monoxide, and of this monoxide
burned to dioxide respectively. Hydrogen and oxygen com-
bined require 11,000 heat-units per pound of hydrogen to raise
them from the solid to the gaseous state.
Let the figure of 7J000 1 units of latent heat per pound be
assumed for the whole of the volatile constituents of coal, that
1 Possibly the figure of 7,000 may be too high, except for the carbon
and hydrogen compounds. The value of carbon is as above about
6,000, as evidenced by the difference between the heat produced by
burning carbon to its first oxide, and then again to its second oxide.
That for hydrogen must be over 7,300, but the values for oxygen
and nitrogen are low. Lechatelier determined the molecular specific
heats of the elements as 6-65 +at, where a is the constant, and t is the
absolute temperature at which the measurement is taken, a was given
by him as 0-001 for a considerable number, but he gave values for
a = 0-008, and there is ample proof in Berthelot's great work that at
high temperatures the specific heats of some substances may be double
and treble the customary figure of 6-65. As the distillation of coal
in a furnace is desired to be effected at at least 1,000 or 1,500F. (say
550C. to 800C.) the specific heats will be something higher than 6 -65.
5
114 LIQUID FUEL AND ITS APPARATUS
is to say, for all that part which does not burn directly on the
grate. This proportion was found above to be 47 per cent,
of the whole, so that, per pound of fuel, 3,290 heat-units (-470
X 7,000) must disappear in evaporating the volatile carbon,
the oxygen, hydrogen, and other gases which exist in combined
solid form in coal.
But we have already found that the total heat generated by
the 48-84 per cent, of fixed carbon produces 7,150 heat-units.
The difference between the heat generated by the fixed carbon
and that absorbed by the volatile hydrocarbons of these parti-
cular Newcastle coals is thus only 3,870 units. This is all the
heat that remains available for raising the temperature.
Now we have found an ultimate temperature of 1,584 when
not allowing for the latent heat of gasification. We must
correct this. It is less in the ratio of 3,870 : 7,150, or 857F.
That is to say, if bituminous coal be burned on a grate and
those parts of the coal which volatilize and burn as flame be
gathered unburned, the temperature of the whole production
of the furnace, including 18 pounds of air per pound of fuel,
would only be 857, or considerably less than that necessary for
ignition.
In the first place, this tells us that it is of the first importance
to diminish the supply of air to a minimum.
By passing only half the air through the grate and adding
the remainder as required to the evolved gases at a subsequent
point, we can at once practically secure double the above tem-
perature, or say 1,600, a temperature at which ignition is
possible. Moreover, even 9 pounds of air is 35 per cent, in
excess of the allowance necessary to burn the fixed carbon of a
pound of bituminous coal, so that it would be liberal practice
to pass only half the total air through the grate. Some of the
heat developed on the grate is at once radiated to the boiler
surfaces ; hence my constant contention that furnaces should
be lined wholly or partially with refractory material in order
to conserve the necessary temperature.
It must not, again, be overlooked that some of the evolved
hydrocarbons do burn on the grate and at the fire surface. In
fact, they commence to burn at once, and continue to burn to
the end so long as conditions are maintained favourable to
continuous combustion.
Rankine's estimate of air as found in ordinary practice was
25 pounds per pound of fuel. The so-called chemical minimum
is 11| pounds. I have assumed 18 pounds as good practice,
but as low or lower than 15 pounds has already been recorded
by Mr. Michael Longridge.
CALORIFIC AND OTHER UNITS 115
If, however, we pass 9 pounds of air through the grate and,
say, a further 6 pounds over the grate, in fine streams, to assist
the combustion of the hydrocarbons, and take care that we
do not abstract heat faster than it is generated by the burning
gases, we ought to be able to secure perfect combustion with
less than 18 pounds of air per pound of coal. There is no
known reason why we should not. The impossibility of smoke-
less combustion has been widely and influentially urged, but
never so much as by those engineers who cram their heating
surfaces right upon the fire and never trouble their brains to
inquire why it is that a thermometer shows the same continu-
ous reading of 32F. in a vessel of melting ice with a flame
under it until all the ice is melted. A piece of coal, like a
piece of ice, is simply so much solidified gas, and absorbs
heat greedily while vaporizing, but it cannot be burned like so
much solid carbon, but must have length and space in which
to mix and combine with the oxygen of the air.
The following figures, based on Berthelot's investigations,
will be useful in this connexion, for they show the enormous
differences which exist between matter in its several states.
Carbon, existing as it does free in Nature in at least three solid
allo tropic modifications, is a peculiarly interesting example.
We do not know it as a liquid or as a gas except in combi-
nation. Its three solid forms of crystalline, graphitic, and amor-
phous, show by their variations of " latent " heat how great
is the effect of form, even when the various forms affect one
state alone. The gaseous state of carbon and the heat neces-
sary to put it into that state are easily argued from the difference
of heat disengagement in the two oxidations. As the table
shows, the oxidation of 1 pound of carbon (diamond) produces
3,915 British thermal units when the product is monoxide.
The heat disengaged by complete oxidation is 14,146 units.
The difference of 10,231 - 3,915 =6,316 units, and this is
obviously the minimum heat of vaporization of the diamond.
Similarly, for the amorphous forms of carbon, the first oxida-
tion produces 4,415 units, and the complete oxidation produces
14,647. Here the same difference is 5,817, and the greater
heat evolution represents the energy necessary to recrystallize
the diamond. Thus we learn that when the diamond crystal-
lized it evolved heat, and we learn that the difference between
graphite and the diamond is less than between graphite and
amorphous carbon. In fact graphite is about six-sevenths
along the road to becoming diamond.
116 LIQUID FUEL AND ITS APPARATUS
Heat generated by the Combustion of 1 pound of Carbon.
State of Carbon.
Product of Combustion.
British Thermal Units
per pound.
Diamond
Cai
i
"bon monoxide
, dioxide
i
monoxide
dioxide
monoxide
dioxide
>
3,915
14,146
14,222
4,415
14,647
10,232
20,463
10,231
Graphite
Amorphous ....
....
Gaseous
2 carbon monoxide .
Metamorphic Conversions.
Heat absorbed.
Car
bon (diamond) .
(graphite) .
Gas
6,316
6,241
5,817
499
74-7
424
(amorphous)
(diamond) .
(diamond) .
(graphite) .
Carbon (amorphous) .
(graphite) .
,, (amorphous) .
Stated briefly, about half the weight of a bituminous fuel
burns upon the grate itself, and produces half the total heat of
combustion ; but that owing to the heat of formation of
gaseous hydrocarbons, and generally to the vaporization of
solid fuel, which absorbs so much heat, only about one-fourth
of the total heat of combustion is sent off from the grate as
sensible heat. The remaining three-fourths are developed
between the fire surface and the extreme range of combustion.
This range varies, of course, with the short or long flaming
quality of the coal. Anthracite coal, which is entirely of solid
carbon, and is therefore almost wholly burned upon the grate,
will produce a temperature at the surface of the grate very
considerably higher than bituminous coal will produce con-
tinuously. This is the reason why so much trouble is experienced
with the grate bars when anthracite is used. It is evident that
every fresh charge of bituminous coal has a very chilling effect
upon the fire, and this is especially the case with intermittent
firing. . The chilling effect of a fresh charge of anthracite is
merely that due to the heating of solid fuel, and is compara-
tively trivial. The bad effect of anthracite coal upon grate
bars is usually attributed to some specially bad quality in the
coal itself ; but this is probably erroneous, the real cause being
simply the high temperature, which melts the cast-iron bar.
This explanation receives confirmation in the fact that bars go
very quickly when they stand above the general surface of the
CALORIFIC AND OTHER UNITS 117
grate, projecting their upper edge into the body of the fire.
The question of combustion is further complicated by the
variation of the specific heat of gases at high temperatures.
The subject has been most thoroughly investigated by M.
Berthelot, to whose great work, Thermochimie, it is hardly
necessary to say the Author is much indebted. That the specific
heat of gases does increase with temperature there is now no
doubt. At ordinary furnace temperatures the effect is not
great, but such as it is, is in the direction of keeping down
temperatures below what they would appear to be when calcu-
lated on the basis of constant specific heat at all temperatures.
First, only half the coal is burned actually on the grate ;
secondly, the other half and- the excess of air work ever to
reduce the temperature ; thirdly, there is the reducing effect of
vaporizing half the fuel, and this is simply enormous, and has
never before been recognized as considerable, if indeed it has
even been allowed to suggest itself ; fourthly, there are the
very active heat-absorbing surroundings of water-cooled plates
or pipes. All these causes work together, with the further
assistance of the increment of specific heat, to reduce the pro-
ducts of bituminous coal to a temperature below that at which
perfect combustion is possible. The combined action is so
powerful that even so-called smokeless Welsh coal will smoke
in boilers of the Belleville type.
In any case, even if the effect of vaporizing the solid fuel
has been over-estimated, the fact remains that it nearly ap-
proaches the figures given, and must prejudicially affect the
furnace temperature. It teaches us at once the complication
involved in burning bituminous coal, and the hopelessness of
those forms of furnace that attempt to extract heat from the
fire within a short distance of the fire itself, and this is equally
applicable to liquid fuels which indeed are so very offensive
if badly burned that they usually are furnished with brick
linings for heat conservation and are burned without smoke.
Flame Length.
The length of flame from a burning hydrocarbon is largely
determined by the intensity of the combustion, as well as by
the perfection of the air admixture. A well mixed gas burning
at a high temperature will produce a short flame, whereas the
same gas burned in water-cooled boiler flues will produce exceed-
ingly long flames. By using suitable furnaces with refractory
linings, combustion may be made to complete itself in a short
LIQUID FUEL AND ITS APPARATUS
distance. It does not follow because a certain fuel produces a
flame 60 or 80 feet in length that it will be necessary to line
the combustion space to a distance of 60 or 80 feet.
The very fact of lining it for one-tenth that length might so
promote rapid combustion as to shorten the flame to even less
than one-tenth. Once, however, that the initial temperature
is reduced below a certain figure, the length of flame cannot be
kept within bounds. This is important to remember, for even a
hot flame will be extinguished after it has encountered the cold
tubes of a water tube boiler. In comparing water tube and
cylinder boilers, it should be noted that the area of cold surfaces
over the fire of a cylinder boiler, either internally or externally
fired, is a very small proportion of the whole heating surface.
In the ordinary form of water tube boiler, where the gases rise
directly between the water tubes, the proportion of cold surface
at once encountered by them is very great. Apart from the
errors already pointed out, the vertical rise of the gases from
the fire is bad practice.
The water tube boiler need not of necessity be thus badly
arranged. It can be set to give the most perfect combustion.
Perfect combustion only takes place at a high temperature.
Flame Analysis.
The vibration velocity of light, by which is meant those
etheric waves which are capable of making their existence felt
to our organs of vision, varies from four hundred billion oscil-
lations per second to nearly eight hundred billions ; that is to
say, about one octave alone comes within the capacity of the
eye to discern. The lower number corresponds with the extreme
red of the spectrum, the higher frequency with the extreme
violet. Beyond the extreme red is a long range of oscillations
- rays invisible to the eye which manifest themselves as
heat. Beyond the extreme violet rays exist a long series of
invisible rays known as actinic or chemical rays. These are the
rays which are most energetic in producing chemical effects.
They are the active rays in photography, and are those which
produce sunburn and the like effect from exposure to electric
light. As these ultra-violet rays produce chemical effects, so
are they produced by chemical action. The more intense the
act of chemical combination, as in the burning of carbon, the
greater will be the actinism of the light produced. Very high
temperatures produced by combustion approach a white
colour the more closely as the temperature rises, and to some
eyes fatigued by too much observation of molten cast-iron
CALORIFIC AND OTHER UNITS 119
the clearance of the final hot slag gives a peculiar neutral light
lavender colour indicative of the high temperature of a common
foundry cupola.
The proportion of rays of any particular colour in a furnace
will indicate the intensity of the action which is going on with-
in that furnace. It is extremely difficult for the most highly
experienced eye to discern the full action of a furnace at high
temperature not perhaps so much because of inability to
estimate the relative amounts of colour present as because of
the superabundance of heat rays which accompany the chemical
rays, and generally the dazzling effect of even moderate tem-
peratures.
The extreme brightness of the steel furnace has necessitated
the use of blue or violet coloured glass to enable the workmeij
to watch the progress of the melt without discomfort.
Engineers have not accepted as they ought to accept the
teachings of physics as an aid to correct practice. Science and
practice have been kept apart. In the combustion of fuels,
this neglect of scientific teaching is almost universal. The
combustion of fuel, especially of bituminous coal, is carried
out along extremely unscientific lines. The assertion is some-
times made that the hydrogen of bituminous coals cannot
be counted upon as useful calorifically. This conclusion is
erroneous.
Hydrogen ignites so very much more readily than carbon, and
at so low a temperature, that the probability is the hydrogens
do burn, and in doing so they snatch the available oxygen
from the surrounding air and deprive the nascent carbon of
any opportunity of combustion, causing it to deposit as soot.
Unless there is sufficient temperature there is no hope of burn-
ing bituminous coal or oil, as it very easily can be burned,
without the formation of smoke. Temperature is so closely
connected with actinism that the analytical investigation of
the light of a furnace will give a fair insight into its conditions
of temperature. By means of transparent media of suitable
composition light may be analysed in a manner that will afford
great assistance in arriving at sound engineering conclusions
and practice. Such media are coloured glasses. A ruby-
coloured glass will cut off all rays of light of higher vibration
than^ruby colour. Only the lower end of the spectrum will
be visible through such a glass. On the other hand, by means
of a violet-coloured glass, all the less active rays than violet
will be eliminated, and the most brilliant of furnaces may be
thereby rendered easily visible, its interior being coloured the
peculiar lavender grey colour, or approaching this tint, which
120 LIQUID FUEL AND ITS APPARATUS
marks the ultra-violet end of the spectrum. The more perfect
the combustion, the larger will be the proportion of violet
light emitted by the flames.
In a well-designed furnace, the whole internal surface of
which is brilliantly incandescent, light proceeds from every
portion of the area and from the flame itself. There are no
non-luminous areas. Occasionally in the mass of flame dark
streaks may be seen. These represent streams of burning
gas, which, while incandescent, are below the violet stage.
They may be traced to a point of disappearance, and they
would probably radiate some light if the colour of the glass
were less violet and more blue.
Let the observation now be transferred to a less perfect
furnace, such as that of the common setting of the water tube
boiler, where the flames rise vertically among the tubes from
the grate surface, and good combustion is impossible. With
the unprotected eye the flames will appear to be giving light
all the way from the fire surface to between the tubes. Com-
bustion appears fair. If, however, these light-giving flames
be examined by the aid of violet glass, they will be cut down to
short tongues of flame projecting but little above the fire sur-
face. Even these tongues of flame give forth little illumination.
Above the flames the gases appear to be simply dark-coloured
streams of gas, soot laden and murky. The violet glass or
analyser has cut out all the rays of small actinic power and
small temperature, with the result that the only remaining
light rays are those immediately above the furnace.
The effect of radiation is to cool the flames below the range
of violet long before they have risen to the level of the tubes.
Apparently there is nothing but radiation to explain the reduc-
tion of temperature.
This method of analysis of the products of the fire is useful
not merely because it enables a furnace interior to be visually
examined with ease and comfort, but because it shows so
clearly the effect of a good design and the bad influence of
premature cooling. It affords most conclusive testimony to
the benefits that accrue from proper design, and should be an
effectual silencer of those who argue that smoke is one of the
unfortunate inevitables of combustion in place of being but a
proof of ignorant and careless design and neglect of the plainer
principles of chemical science.
The use of violet-coloured glass is essential. It is not
simply that it is requisite to reduce the amount of light which
meets the eye and renders vision impossible. Such a result
could be attained by means of glass otherwise coloured, as by
CALORIFIC AND OTHER UNITS
121
smoke, so that it is less transparent, but still not diffusive, as
is ground glass.
Violet glass or the higher blue colours are necessary because
Fig. 7,
WEIR SMALL TUBE BOILER, WITH REFRACTORY COMBUSTION
CHAMBER.
The walls of the furnace are lined with fire-brick slabs, threaded on the inside row of tubes,
and beyond the furnace chamber is a further combustion chamber also lined with fire-brick. The
hydrocarbon gases have thus a long distance to travel before they reach any serious area of cool
tube surface ; the furnace is maintained at a high temperature, and there is large space for the
combustion of the gases in a hot chamber, whereby alone combustion can be secured perfect. This
boiler can be fixed either from side or ends, and represents the latest and most improved practice
in water tube boilers, recognizing the principles essential to perfect combustion. The hot gases
travel along the length of the tubes, completely enveloping them. The outer casing is of fire-brick
slab with an outer sheet of steel. The following shows result of tests of two of these boilers
with coal
Grate surface
Ratio to heating surface
Funnel draught
Calorific value of coal-
Coal per square foot per hour ....
Evaporation per Ib. of coal from and at 212'
Ditto per square foot heating surface
Boiler efficiency ,
Fire thickness ,
Funnel temperature
Steam pressure, Ib 285
Single -ended.
Double-ended.
48-75 48-75
53 53
1 1
1 1
45 45
4T3 4l
3-21 forced 0-6 nat.
3-5 forced 0-625 nat.
13-38 13-38
13-2 13-2
62-2 29
63-4 29-1
9-05 Ib. 10-7 Ib.
8-65 It. 9-76 Ib.
12-5 Ib. 6-918 Ib.
13-27 Ib. 6-86 Ib.
67-65 80-0
65-5 74
12 in. 12 in.
9 in. 9 in.
789F.
930F. 780 F.
185 251
275 276
of their specially analytical properties. I am not prepared to
say that perfect combustion cannot occur at temperatures
below those which are associated with the light rays that can
traverse violet glass. It is, however, very probably true that
122 LIQUID FUEL AND ITS APPARATUS
the violet degree of actinism must be very fully developed if
combustion is to be perfect, and this degree of actinic effect
cannot be associated with temperatures that can be secured
in any furnace so arranged that the gases rise vertically from
the grate surface to pass between the water pipes before they
have been thoroughly commingled and burned in a free space.
Jghl Gray :
No 3.
Darker Gray Smoke
_Vcry Dark Cray Snjoke,
Fig. 8. RINGELMANN'S SMOKE CHAET. No. ALL WHITE. No. 5
ALL BLACK.
Thus the ordinary arrangement of water-tube boilers is abso-
lutely hopeless and impossible. A single inspection of such a
furnace through the analyser will effectually convert any open
mind, and point the necessity for better practice.
Mr. Weir, of Glasgow, designed the small tube boiler shown
in the Fig. 7, with the necessities for combustion before him.
CALORIFIC AND OTHER UNITS 123
It will be observed that in this boiler the gases from the coal
must pass through a large firebrick-lined furnace and com-
bustion chamber before they reach the tubes. Combustion
is thus assured by a sufficient conservation of temperature.
The principles which underlie perfect combustion are here
assured, and smokelessness results. The same principles
applied to liquid fuel are followed by equally happy results.
But in recent practice with liquid fuel it is found possible
to attain very good combustion with little or no smoke without
fire-brick lining to the furnace. See the latest practice of the
Wallsend Slipway and Engineering Co.
Ringelmann's Smoke Chart.
This chart (fig. 8) is very useful as a means of comparing
smoke. The chart should be ruled in squares of about eight
inches, and hung about 50 feet from the observer, at which
distance each square assumes a uniform tint all over, the rulings
being indistinguishable. There are six cards in a set No.
being all white and No. 5 all black.
The proportion of the lines is as follows
No. 1. Black lines 1 mm. thick, spaces 9 mm. wide
No. 2. 2-3 mm. ,, 7-7
No. 3. 3-7 6-3
No. 4. , 5-5 4-5
J5 * ** J) 5)
The illustrations are reduced from a larger size, and the pro-
portion of black and white is of course preserved.
In marine work smoke may be observed by means of windows
placed in the uptakes. An incandescent lamp on the other
side of the uptake should be visible through the smoke. It
should not be perfectly clear, for an entire absence of smoke
may indicate an excess of air. A slight smoke indicates, when
conditions generally are good, that- air is not greatly in excess.
Part II
PRACTICE
CHAPTER VII
OIL FUEL AT SEA.
Oil Storage on Ships.
OBVIOUSLY the double bottom of a ship now used for
water ballast is the place in which to carry oil fuel, leaving
other spaces free.
As each fuel tank is emptied it can be filled with water.
Lloyds' Register of Shipping publishes certain rules applicable
to existing vessels, which should be studied. As they may
be changed from time to time, they are not given in this book.
Both Lloyds and the Board of Trade place only necessary
safeguards, and do not oppose the use of liquid fuel. Sir
Fortescue Flannery states that the peculiarly penetrative
qualities of refined petroleum do not attach to the more viscous
fuel oil, which he avers to be as easy to retain as water by the
same class and quality of riveted work.
Additional water-tight subdivision is, however, advised as
a safeguard against the scend of a half -empty oil tank, but in
small or medium ships the usual subdivision is thought sufficient.
In the system of storage adopted on the s.s. Murex, a vessel
with all her tanks adapted to carry either general cargo or
refined oil, but not originally planned for using liquid fuel, for
which purpose she was converted by the Wallsend Slipway
and Engineering Company, there is no double bottom below the
cargo tanks, which extend to the skin of the ship, but the bottom
is double below the engines and boilers, and coffer-dams are
put in at the fore and aft ends of the cargo space, and, with the
fore and aft peaks, have been arranged to take the fuel oil.
Service tanks were placed in the 'tween decks.
A flange on deck is coupled up to the pipe from the store
tank, and oil passes by pipes to the various tanks, w r hence a
pump lifts it to the service tanks, which are provided with
overflow pipes, steam heater coils, and water drain pipes.
All leakage in the power compartment is intercepted by the
drainage wells, so that the ordinary bilge is kept free. These
intercepting wells have their own suction and delivery pipes.
127
128 LIQUID FUEL AND ITS APPAKATUS
In a regular oil tank steamer on the Flannery-Boyd system,
the oil to be used is carried in the fore and aft peaks and in
the ballast tanks under the engines and in the division bulk-
heads, the cargo of oil being carried in the remainder of the ship.
Between the oil tanks and the remainder of the ship it is con-
sidered necessary to place a coffer-dam. In a tank steamer
the rest of the ship means the engine and boiler compartments.
This coffer-dam is two transverse stiffened bulkheads extending
across the ship and properly filled with water as a safeguard
against leakage of oil. In practice this coffer-dam is often
filled with fuel oil, a practice upon which doubts may be ex-
pressed, for apparently this destroys much of the safety in-
tended to be given. Oil fuel is also carried in the double
bottom below the engine compartments, which again is a point
open to discussion, for a vessel might be so injured by going
aground as to flood the boiler compartment with oil with risk
of explosion.
It is safer practice to exclude oil from both the power com-
partment bottoms and from the coffer-dams, the latter being
kept perhaps narrower than they are now.
Where the oil is of a specially heavy class, there might not
be much risk if it did leak into the firehold, and good residuum
or astatki would be something of a safeguard between the
main tanks of crude oil and the boiler room. Be this as it
may, the presence of a narrow water space outside the oil
fuel coffer-dam gives a better margin of safety.
The riveting of oil-tight plating is usually 3 to 3J diameters
in pitch. Old ships, to be rendered fit for oil carrying, which
have rivet spacings of 7 to 8 diameters, may thus have a new
rivet put into each spacing. Such ships usually require
additional deck beams, as a rule. Ships should have not less
than eight water-tight compartments, and the separating
bulkheads, if oil tanks, ought to be connected directly to the
skin of the ship, all possible empty spaces being avoided. Oil
is filled into tanks so as to stand 2 feet above the upper deck
level in the expansion trunks. The gases driven off from oil
are heavy, and settle at the bottom of any space into which
they obtain access. Ventilation is required to get rid of such
gases. Air should be admitted through cowl heads to the upper
part of the place to be ventilated and removed from the lower
part. It will dilute and carry off the accumulated gas. Such
air outlets should have induction openings to assist the current.
The general direction of air movement in a ship is from aft
forward, and advantage may be taken of this in arranging the
ventilation.
OIL FUEL AT SEA 129
Great care is needed to joint all oil pressure pipes carefully.
The screw threads should be good, and ought to make tight
joints with only a little smear of litharge and glycerine, or
Venetian red and shellac. Pipes must not be concealed be-
neath floor plates, in bilges, or behind casings, but ought to
be fully exposed to view.
An oil cargo being so easily mobile with movement of the
ship, it is necessary that the tanks should be full, so that there
may be no surging. Hence the use of expansion trunks to
permit of this, and allow expansion without waste or pressure
being the result. Surging plates must be employed in those com-
partments, which may not be always full, as the fuel tanks, and
no compartment should occupy too much of the length of a ship
without a bulkhead. Similarly bulkheads are stiffened from
one to the other by longitudinal plates, which check transverse
surging, or scending. The ordinary cargo boat, when fitted for
fuel oil, is re-riveted when necessary, and the oil fuel is carried in
the double bottom, and can be replaced, as consumed, with
water ballast. Oil is also carried in the fore and aft peaks.
Oil Steamers.
One of the best examples of an oil steamer is the s.s. Trocas,
which has been fitted for liquid fuel by the Wallsend Slipway
and Engineering Company, Ltd., the system adopted being
the Flannery-Boyd with Rusden & Eeles burners.
The ship is an oil-carrying vessel of 347 feet in length and
45-7 feet beam, and at full load carries 6,000 tons of oil.
One of the greater obstacles in the way of fitting old steamers
with liquid fuel-burning arrangements is the difficulty of con-
structing suitable spaces to carry the liquid fuel. Ordinary
coal bunkers are of course not suitable, as the riveting and
plating is not oil-tight. In the Flannery-Boyd system the
oil is carried in all the ballast tank spaces throughout the ship,
namely, the fore and aft peaks, the double bottom ballast tanks
under the engines and boilers, the forward ballast tank adjacent
to the fore peak, and the forward and aft coffer-dam.
The main difficulty in carrying liquid fuel in these spaces
is that some water always remains in a ballast tank, owing to
the difficulty of completely draining it. This water becomes
mixed with the liquid fuel, and passing to the burners causes
dangerous explosions, and generally puts out flame. It is
therefore necessary to eliminate . the water. To do this two
settling tanks of large capacity are placed in the 'tween decks
amidships, adjacent to the boiler room bulkhead. These tanks
130 LIQUID FUEL AND ITS APPARATUS
are^fitted with heating coils to enable the liquid fuel to be
heated to a sufficient temperature to allow of the water freely
separating. The water then settles to the bottom of the tank,
and can be drained off.
Each tank is made of sufficient size to contain half a day's
supply, so that half a day is allowed for the water to become
separated. From these separation or service tanks the oil
gravitates to the burners, and is sprayed by a jet of steam.
Each furnace is fitted with two burners, and the furnace
arrangements are such that the complete coal burning gear
remains intact when burning liquid fuel, so that the system of
either coal burning or liquid fuel burning can be resorted to at
wiU.
If the vessel is burning liquid fuel, and it is found necessary
from economical reasons to resort to coal burning, it is only
necessary to rake a few broken fire-bricks from the bars and
disconnect the burners and light a coal fire. This operation
can be carried on without stopping the vessel at sea ; the
whole operation in a large vessel can be carried out within an
hour.
The s.s. Trocas has three large single-ended boilers and one
donkey boiler. The large boilers have each three furnaces,
and the small boiler has two furnaces. All are fitted for liquid
fuel.
The question of safety and flash-point is of importance.
The British Admiralty did require a flash-point of 270F.,
but now accept a minimum of 175: Lloyds' register, of 200,
now reduced to 150, while the German authorities have
accepted as safe 150. Fuel of the lower flash has been in
constant use for four years in British and Dutch mercantile
vessels, with complete immunity from accident. It is not
desirable to fix a flash-point higher than is really necessary for
safety, because high -flash points are obtained by removing
the more volatile parts of the liquid, so as to leave a thick
and sluggish residuum, which requires much power to pulverize
it. The London County Council ask for 150. ^
Comparative Advantages for War Vessels.
Sir Fortescue Flannery says : The problem that confronts
every designer of a warship is the combination of the maximum
speed, armament, ammunition supply, protection, and range
of action in the smallest and least expensive hull, and any
reduction of weight and space of these is a saving which acts
and reacts favourably upon the problem. The comparisons
between coal and oil fuel realized in recent practice are that
OIL FUEL AT SEA 131
2 tons weight of oil are equivalent to 3 tons weight of coal, and
36 cubic feet of oil are equivalent to 67 cubic feet of coal as
usually stored in ships' bunkers ; that is to say, if the change
of fuel be effected in an existing war vessel, or, applied to any
design without changing any other of the data than those
affecting the range of action, the range of action is increased
50 per cent, upon the bunker weight allotted, and nearly 90
per cent, upon the bunker space allotted.
" The coal protection of cruisers, if an advantage a matter
of opinion would disappear with the use of liquid fuel, because
it would be for the most part stowed below the water line, if
not wholly in the double bottom. /The double bottom and
other spaces, quite useless except for water stowage, would be
capable of storing liquid fuel, and the space now occupied by
coal bunkers would be available for other uses.
" The ship's complement would be reduced by the almost
complete abolition of the stoker element and the substitution
of men of the leading stoker class to attend to the fuel burners
under the direction of the engineers, and the space of stokers'
accommodation, their stores and maintenance, would be saved.
The number of lives at risk and of men to be recruited and
trained over a long series of years would be reduced, without
reducing the manoeuvring or offensive or defensive power of
vessels of any class in the fleet.
" Re-bunkering at sea so anxious a problem with coal
would be made easy, there being no difficulty in pumping from
a store ship to a warship in mid-ocean in ordinary weather.
Three hundred tons an hour is quite a common rate of delivery
in the discharge of a tank steamer's cargo under ordinary
conditions of pumping.
" The many parts of the boiler fronts and stokehold plates,
now so quickly corroded by the process of damping ashes before
getting them overboard, would be preserved by the action
of the oil fuel, and the same remark applies to the bunker
plating, which now so quickly perishes by corrosion in way of
the coal storage.
" Liquid fuel, if burned in suitable furnaces with reasonable
skill and experience on the part of the men in charge, is smoke-
less. It is easy to produce smoke with it, but this is evidence
of its being forced in combustion, or of the detailed arrange-
ments of the furnace being out of proper proportion to each
other. In regard to smokelessness, it is, when used under
conditions customary in the merchant service, not inferior to
Welsh coal, and superior to any other coal ordinarily in use.
" The cost of oil in the East is less than the cost of Welsh
132 LIQUID FUEL AND ITS APPARATUS
coal when the cost of transport and Suez Canal dues are added
to the original price of coal as delivered in a Welsh port."
It is only since Texas oil has been discovered that the success-
ful competition of oil has appeared probable to the west of the
Suez Canal. In the mercantile marine advantage is gained
by a reduction of the stokehold complement, a crew of thirty-
two being reducible to eight.
Fast Atlantic liners find it difficult to get coal to their boilers
for the firemen to burn, and they lose time in consequence, even
when their engines and boilers are in perfect order. This
difficulty disappears with oil, and there is, a saving of space
previously occupied by men and stores. '
Allowing 3 tons of coal to be equal to 2 tons of oil, a first-class
Atlantic liner will gain 1,000 tons for freight, as well as the
whole of the bunker space. That is, with oil in the peaks
and ballast tanks, there will be a gain of 100,000 cubic feet of
paying space, and for most ships at least a fourth of the coal
bunker space could be used for cargo. There is in addition
the saving in time when coaling. Oil is pumped in without
the help of a man. No fires require to be cleaned ; there are
no ashes to be removed. /
Fires made by oil are perfectly steady, the steam pressure is
constant, while the temperature of the stokehold in steamships
is lower, since the furnace doors are never opened and hot
cinders are not pulled out into the room. /
The loss of heat up the stack is reduced owing to the clean
condition of the tubes and to the smaller amount of air which
has to pass through the furnaces for a given calorific capacity
of fuel, and there is a more equal distribution of heat in the com-
bustion chamber, as the doors do not have to be opened ; con-
sequently there is a higher efficiency. The heat is easier on
the metal walls of the boiler, being better diffused over the
whole surface.
The cost of handling fuel, by pumps, is reduced.
No firing tools or grate bars are used, 1 to damage the furnace
Hning.
No dust fills the tubes to diminish the heating surface.
The fire can be regulated from a low to an intense heat in
a short time. /
Many factories in Pennsylvania and Ohio had to increase
their boiler capacity by about 35 per cent, when returning to
the use of coal on account of the high cost of oil.
1 Grate bars may be employed, under certain conditions, as explained
elsewhere.
CHAPTER VIII
MARINE FURNACE GEAR
r I ^HE use of steam or of air for atomizing is a mixed ques-
A tion. Steam is more convenient, and is naturally first
used, but it becomes so severe a drain on the fresh water supply
that it is practically inadmissible at sea.
The claim that its oxygen is set free by the fire and burned
with advantage to the evaporative efficiency of the boiler
cannot be allowed. The dissociation of water or steam absorbs
exactly as much heat from the fire as is given back by the re-
combination.
Some makers of atomizing apparatus claim to secure a softer
flame with steam, but so far as our chemical and physical
knowledge extends, air ought to be superior. It requires,
however, to be first compressed, and it is desirable that it
should be heated to near the oil flash-point, so that the oil may
burn freely as soon as' atomized.
Ships in the Caspian Sea use steam, but are never far from
land. Fuel may be injected under pressure and break up against
an obstacle at the furnace mouth, or it may be vaporized by
heat before reaching the furnace mouth.
In Mr. Howden's modification, fuel is injected under pressure
mixed with air previously heated by the waste chimney gases,
and this system has been fitted to the North German Lloyd
steamers Tanglier and Packman ; by Workman, Clark & Co;,
of Belfast.
In the s.s. Murex already named, which arrived in the Thames
in the spring of 1902 from a voyage of 11,800 miles, from Singa-
pore via the Cape, the furnaces were never touched. Her coal
consumption averaged 25 tons per day. With oil fuel the daily
consumption is 16 tons only. The fuel supply arrangements,
Fig. 9, consist of steam pipes A A A A, oil pipes B BB B, and
burners C C C C, hung on swivels D, so as to be adjustable in
position, and to allow the doors to open upon the same axis or
hinge centre. Coal can be reverted to, when the burner orifices
F F F F are closed by the pivoted slides. In Fig. 10 is shown
133
134 LIQUID FUEL AND ITS APPARATUS
the brick work H H in the form of pillars and arches against
which the flames first impinge. At K K are further baffle
bridges to keep the flame from too severely striking the back of
the combustion chamber carrying the stay nuts, the tube ends,
rivet seams and parts liable to injury from excessive local heat.
The form of burner is the
Eusden-Eeles
type, Fig. 67, with adjustable annular orifices both for steam
and oil (see Chapter XIX). They possess the quality of ad-
justability while at work essential to secure the most perfect
Fig. 9. FURNACE FRONTS or s.s. " MUREX."
possible conditions of combustion. The oil annulus is sur-
rounded by a steam jacket, and steam enters the middle cham-
ber and escapes into the furnace round the central stem, which
is drawn back by revolving the end wheel and allows an annular
spreading steam jet to escape round the flaring end of the
stem. Oil finds its way to the little ring chamber immediately
at the nozzle, and is directed down the sloping ends of the slide
directly upon the steam jet which pulverizes it and spreads it
in the furnace. The oil slide is drawn back by rotating the larger
handle.
Interchange of Coal and Oil.
To permit the ready interchange of coal and oil the s.s. Trocas
with fitted as in Fig. 11, the coal grates remaining and being
MARINE FURNACE GEAR
135
covered with 8 inches of broken brick. The brickwork B, G y
and D always remains in place.
To change over from oil to coal the burners are swung back
to clear the furnace door, the broken brick is raked out, and
I , I
Fig. 10. ARRANGEMENT OF FURNACE BRICKWORK, s.s. " MUREX."
ordinary coal firing resumed. In twenty-eight minutes after
steaming full speed under oil the Trocas was again at full speed
under coal.
It is, however, found as the result of experience of long
voyages that it is better not to let the firebars remain in when
136 LIQUID FUEL AND ITS APPARATUS
using oil, for, at the worst, the change over can be made in a
few hours, and better results obtained from oil with the more
approved arrangement. The general arrangement of the s.s.
Trocas is that of Fig. 10.
It is estimated by Sir Fortescue Flannery that the atomizing
steam will amount to 0-2 pound per i.h.p. per hour. The waste
is made up by large evaporators, usually in three interchange-
able sections which should be worked steadily.
Two burners in each furnace are found to give better results
than one larger burner, being more easily adjustable and
maintaining continuity of flame. There is also greatly dimin-
Fig. 11. FURNACE ARRANGEMENT OF s.s. "TROCAS."
ished chance of extinguishment of the flames by an accidental
access of water from imperfectly dried oil.
The Flannery-Boyd System for Steamships.
The chief object of the system is to separate from the oil
fuel the water which may have become mixed with it in any
manner and also to enable oil fuel to be carried in ballast tanks
or other compartments where water is usually carried.
To get rid of the water two or more settling tanks are used,
in which the oil remains a sufficient length of time to permit
of the water depositing. In each tank is a heating apparatus
to assist the action, for by heating the oil the water is more
quickly deposited, owing to the expansion of oil being greater
than that of water, and because the oil is made less viscous by
MARINE FURNACE GEAR
137
heat. Two or more tanks must be used, so that while the
water is being deposited in one tank the dried oil in the other
may be fed to the burners. The system is applicable to any
system of burning oil.
Oil. FUEL
op SER^ICC
ON THE
Boyo PHTE.NT
N.B. SERWCE TANKS NUMBER 2 MAY BE MADE ROUND, SQUARE OR BUILT INTO SHIB
SUCTION PIPC raui-i BULLBST
Fig. 12.
Fig. 12 shows the various pipe arrangements, the oil feed
pump 3 drawing from the ballast tank 1 through a pipe 4
and delivering by pipes 5 to the service tanks 22, whence the oil
gravitates by way of pipes 7 to the oil burner supply pipes 9.
i I
bC
S
138
MARINE FURNACE GEAR
139
Overflow pipes 13 carry back any surplus oil to the main tanks,
and separated water is discharged by pipes 12.
The service pipes are kept free of pressure by vent pipes 14,
carried up several feet.
The general arrangement of an oil ship is shown by a fairly
MIDSHIP SECTION.
poqp_ D_
CONTINUOUS
TftUHK SIDE.
EXPANSION
OIL TRUHK
MAIN D
OILTIGHT
CENTRE LINE
BULKHEAD'.
Fig. 13a. MIDSHIP SECTION OF OIL TANK S.S. NEW YORK.
recent example, the s.s. New York, Figs. 13, 13a, built by the
Palmer "s Shipbuilding and Iron Company, Ltd., of Jarrow-on-
Tyne. In this class of vessel all the seams and butts of the shell
plating, decks, and bulkheads are riveted, and the rivets are
spaced, for oil tightness, 3| diameters centre to centre, instead
140 LIQUID FUEL AND ITS APPARATUS
of 4 diameters as required for water-tight work. Special care is
also taken to avoid as far as possible any rivet passing through
more than two thicknesses of plating. The vessel is divided
into eight pairs of oil tanks with expansion trunks for each pair.
There is a coffer-dam at the back of No. 1 tank, separating it
from the power department. A small hold for miscellaneous
cargo is placed forward by No. 8 tank, from which it is separated
by a coffer-dam. The oil tanks are divided along the centre
line of the vessel by an oil-tight bulkhead, so that there are
really sixteen oil cargo tanks. The length of the New York is
428 feet between perpendiculars, the breadth 54 feet 6 inches,
and the depth 32 feet. The water ballast tanks extend the full
length of the ship below the oil tanks. Coal bunkers are pro-
vided on each side of the engine and boiler compartments
and also forward of the boilers, between the boiler compart-
ment and the after coffer-dam.
The Orde System.
In Figs. 14, 14a, 15, are shown various arrangements of oil
fuel burning by Sir W. E. Armstrong, Whitworth, and Co., of
Newcastle-on-Tyne, according to the system of Mr. C. E. L.
Orde.
Fig. 14 shows the general arrangement for a water tube
boiler. Steam, superheated in the casing by means of a pipe
carried round the steam dome, is taken to a subsidiary steam
header, whence branch pipes issue to five separate burners.
Oil is fed by similar pipes from a second header supplied from
the bunker or oil tank through a heater on the right. This
contains exhaust steam, and heats the oil on its way to the
burners. The oil is drawn off from the tank as in Fig. 14a, by
means of a floating arm, which always takes the highest oil from
an area which is heated by a steam pipe coil placed under the
intake of the oil pipe. A small pump forces the oil to the distri-
bution system, a relief pipe carrying any excess back to the
pump suction. Air, heated in the ashpit through which the
pipe is laid, is supplied to the burners by a separate pump on
the left. The copper steam pipe to the float is flexible to allow
for the float movement, and the float is kept steady laterally
by a piece of angle iron bent to a circular form to suit the path
of the float arm. Blow- through steam pipes are fitted for
clearing the oil pipes when required. The atomizer, Fig. 15,
is triple, oil entering through the centre passage, with needle
regulating spindle. Steam comes outside the oil through an
annular passage and air is introduced outside the whole, the
ofttbter Separating Apparatus.
Fig. 14a. FUEL OIL BUNKER. DRAW-OFF PIPE AND FLOAT.
142
MARINE FURNACE GEAR
143
mixture being blown through the spreading orifice as spray.
The oil does not come through as a solid jet into the com-
bining nozzle, but as a thin annular shell jet easily atomized.
The atomizer, however, differs from some others which admit
air at the centre. The illustration shows the latest pattern
(1911).
Highly superheated steam is intended to be used (preferably
600F.).
The annexed table from a paper by Sir F. Flannery, in the
Transactions of the Institution of Naval Architects, gives a few
results.
Ship.
System.
Oil per
I.H.P.
per hour.
Coal ! Heating
I P HP. , Surace '
i
I.H.P.
Per cent,
of gain
by use
of Oil.
F. C. Laeisz
Sithonia .
Murex .
Syrian
Khodoung .
Korting
Howden .
Rusden-
Eeles
Ord'e . .
Ib.
1408
1-065
1-3
16 tons p. d.
1-32
1-08
Ib. ! sq. ft.
1-93 7,560
149 6,924
25 tons 5,202
per day
2,480
1-67 2,700
2,200
2,500
800
960
27-0
28-6
36-0
35-5
In each case, except the Sithonia, which had quadruple
engines, the engines were triple expansion.
Lancashire Boiler with Orde's System.
The Lancashire boiler as arranged by the Wallsend Slipway
and Engineering Company, for burning oil with or without a
grate, is given in Fig. 16.
A single injector is applied to each furnace door, the grate is
covered with broken brick, and at the middle of its length
a brick baffle is built, round and through which the flames
escape, and after passing a low bridge at the rear of the grate
escape unimpeded.
Without a grate, the furnace is fitted with a brick oven and
striking bridge, beyond which is a cellular baffle of brick
which gives a final mixing to the gases before they are quite
consumed.
A gravitation tank is placed about 10 feet above the level
of the atomizers, with suitable valves, vent pipe, overflow and
gauge. The supply pipe to the atomizer has a strainer in its
course.
These various arrangements differ very little from those of
other engineers, the chief object being the atomizing and the
arrangement of the fire-brick oven and bridges.
0/7
Fig. 15. ORDE AND SODEAU'S ATOMIZER, ARMSTRONG WHITWORTH & Co.
144
8
145
146 LIQUID FUEL AND ITS APPARATUS
The Wallsend System of Oil Burning.
In the latest practice of the Wallsend Slipway and En-
gineering Co. the
oil is injected into
the furnaces (Fig.
17) under pressure
by m eans of
pumps, no steam
being used in
atomizing the oil,
but only steam to
drive the fuel
pumps and to heat
the oil in the
heaters.
After the steam
has done its work
it is delivered to
the condenser and
there is no loss of
fresh water.
There are no air
compressors o r
blowers required,
the only working
parts being the oil
fuel pumps them-
selves, so that
wear, tear and
breakdowns are
reduced to a mini-
mum.
The liquid fuel
is drawn from the
storage tanks by
duplex pumps.
On its way to the
pumps the oil
passes through a
duplex filter, ar-
ranged that each
side can be cleaned
whilst the other
side is in use.
MARINE FURNACE GEAR 147
The pump delivers the oil first to a receiver of sufficient
capacity to ensure its discharge to the burners under a steady
pressure. From the receiver the oil passes through the main
steam heater.
The temperature of the oil on leaving the heater is recorded
and the oil then passes through a discharge duplex strainer of a^
similar design to the suction strainer and thence to the burners
(Fig. 18), to which are fitted special air distributors. These ,'
consist of an inner and outer cylinder having vanes fitted / l
between them.
These vanes are arranged specially and give a rotatory
motion to the air and oil spray.
Two sets of nozzles are supplied to allow a wide range of
power being developed by the boilers.
The air distributors are adjustable so that the amount of air
entering the furnaces can be regulated to a nicety and complete
combustion obtained.
Tests carried out on this system by Professor Barr on Messrs.
J. Howden & Co.'s works boiler at Glasgow showed 16-22 Ib.
of water evaporated per Ib. of oil burnt from and at 212F.
As a result of Messrs. J. Howden & Go's experience with the
system they have decided to fit the Wallsend System as shown
in Fig. 17a in conjunction with their closed system of forced
draught.
In this and Fig. 17 it will be noticed that there is now very
little brickwork in the furnace of a marine boiler, and that the
whole circumference of the furnaces is available as heating
surface.
This is possible with the fine atomization and air mixture,
combustion being well advanced before the conical spray reaches
the furnace plates. When there are no firebars the whole of
the furnace surface is efficient as heating surface and the lower
part of the boiler is thus kept hotter than when the ashpit
bottom is shielded by a grate. Each spray nozzle has its sur-
rounding annular air passage with whirl vanes, and this keeps
the outer trunk cool. A protecting face of brickwork is em-
ployed as shown.
The annexed table gives the results of the tests above re-
ferred to and made on Messrs. Howden's works boiler of
11 ft. diameter X lift. Gin. long with two 39 inch furnaces
and a total heating surface of 1,358 sq. ft. The steam was
stated to be dry, or nearly so. 1
1 The dryness was tested by calorimeter, but the author places no
reliance on any known system of taking samples of steam out of a
steam pipe. The sample passed to the calorimeter cannot be known to
be accurate.
Fig. 18. THE WALLSEND PRESSURE BURNER.
148
MARINE FURNACE GEAR
149
It will be noted that the weight of oil per hour figures out at
nearly 46 Ib. per square foot of cross section of furnace
in trial 1, and 31 Ib. in trial 2 with lighter draught.
Reckoned on the longitudinal section of the furnace as though
each furnace had 20 sq. ft. of grate area, as it might have
with grates, the fuel per square foot per hour works out
at about 23 and 16 Ib. respectively, or a heat production per
square foot of " grate " of about the equal of 30 and 21 Ib. of
coal.
SUMMARY OF RESULTS OF TRIALS OF THE WALLSEND PATENT
LIQUID FUEL BURNING SYSTEM WORKING WITH HOWDEN'S
FORCED DRAUGHT.
Duration of trial . . . hours
Number of burners per furnace .
Class of oil used . . (Scotch)
Calorific value (nett) of the oil
B.T.U.
Specific gravity of the oil at 60F.
Steam pressure . Ib. per sq. in.
Average temperature of feed
water deg. F.
Pressure of air entering furnaces
in. of water
Temperature of air entering fur-
naces deg. F.
Description of smoke at chimney
top
One No. 18
Pumpherston
18,770
0-868
155
115
190
Verv light to
2
One No. 16
Pumpherston
18,770
0-868
155
120
fin.
185
Verv light to
Temperature of gases at the foot
of chimney . . . .deg F
none
488
none
420
Weight of oil burned per hour Ib.
Weight of oil burned per hour
per burner Ib.
Weight of water evaporated per
932
466
13 050
633
316-5
9 000
Weight of water evaporated per
Ib. of oil burnt . . . . Ib.
Equivalent evaporation from and
at 212F Ib.
14-00
15-91
14-22
16-22
Equivalent evaporation from and
at 212F. per sq. ft. of heating
surface per hour . . . Ib.
Thermal efficiency of boiler .
10-92
82-3%
7-55
83-9%
The arrangement of the Wallsend System to a marine boiler
of Scotch type is given in Figs. 19, 19a, and the general arrange-
ment for a water-tube boiler is given in Fig. 20.
150
161
152 LIQUID FUEL AND ITS APPARATUS
The Korting System.
In this system, as fitted to the Hamburg- American s.s. F. C-
Laeisz several years ago, the water was first separated out of the
oil which is raised by a pump, and heated to 60C.= 140F.
by a heater on the suction pipe, and filtered before it reaches
the pump valve, and thence delivered to a second heater,
which raises its temperature to 90C. = 194F., and after a
second filtration and under a pressure of thirty pounds per
square inch, injected round a screwed needle, which causes the
hot oil to spray itself. The bars are omitted, and the furnace
lined in fire-brick and the air is admitted through adjustable
perforated gratings.
The front of the oven is a disc of fire-brick with a small open-
Fig. 21.
FURNACE or s s. " F. C. LAEISZ," WITH BRICKWORK.
SYSTEM.
KORTING
ing through which the spray is delivered and air is admitted.
It this system the oil is made to spray itself and is sufficiently
atomized by the pressure and the action of the screwed needle
round which it escapes.
The furnace of s.s. F. C. Laeisz is shown in Fig. 21 with the
furnace lining and the brickwork of the combustion chamber
also. In Fig. 22 the Korting sprayer is shown in section, with
its spirally wound needle which throws the oil into rapid ro-
tation and causes it to spread widely at the nozzle, exactly as
in the case of the Korting water cooling sprayers. It was then
considered essential to line the furnace in order to secure perfect
combustion and insure that all the oi] is vaporized before it
MARINE FURNACE GEAR
153
reaches the chilling zone of unprotected water cooled plates,
but later practice by the Wallsend Co. appears to have succeeded
in securing com-
bustion without
smoke in an un-
lined furnace as in
Fig. 17.
The diameter of
the jet orifice is
1 to 3 mm., and
in later forms
there is a crown or
disc set round the
nozzle -and pierced
with holes of 1-25
mm. diameter,
through which air is intrained. The output under a pressure of
six kilos =84- 4 pounds, was as follows when tried at Cherbourg
Orifice , . 1 mm. 1 mm. 25 1 mm. 6
Oil per hour . . . 65 k. 100 k. 135 k.
143 Ib. 220 Ib. 297 Ib.
Tried on the locomotives of the Vladi-Kavkaz Railway these
atomizers with double jets sprayed 230 kilos = 506 Ib. per
hour under a pressure of only 4-2 k. =59-8 Ib. From the
Fig. 22. ROUTING ATOMIZER.
Fig. 22a. ROUTING ATOMIZER.
trials made by the French Navy it appears that these
mechanical atomizers work very regularly and, moreover,
silently, if the oil is first filtered and heated to 80C. = 176F.
They are recommended for getting up steam, the force pump
being hand worked until such time as steam is produced
sufficiently to work the pulverisers.
M. Bertin lays stress on the benefit of supplying oil to a
burner at a considerable pressure and at a high velocity, for
even with air or steam atomizers the fine jet will atomize more
easily, for an oil pressure of three kilos, for example, permits of
a velocity four times as much as is given by a head of 2 metres.
CHAPTER IX
LIQUID FUEL APPLICATIONS TO LOCOMOTIVE BOILERS
The Holden System.
IN this system, the first to come into extensive use in Great
Britain, the object has been to combine liquid and solid
fuels so that either or both can be used indifferently without
a moment's notice of the change.
Mr. Holden, of the Great Eastern Railway of England,
primarily devised his system for getting rid of the tars pro-
duced by oil gas apparatus ; but he has used many liquids for
fuel, including coal tar, blast furnace tar and oil, shale oil,
creosote and green oils, astatki and crude petroleum. Loco-
motives thus fitted are clean to work, make no dust, smoke or
sparks, have little wear of tubes or fire-boxes and have little ash
and clinker to remove. Steam can be raised rapidly, adjusted
at an even pressure, and waste at the safety valve is prevented.
Any boiler can be fitted for liquid fuel without alteration of
furnace, though it is desirable to add a fire-brick lining on the
tube plate below the arch.
The fire is made up thin with coal and about 120 pounds of
broken fire-brick. The ashpit damper is kept sufficiently open
to maintain the fire bright.
There is nothing striking to be seen from the footplate, with
the exception of an extra fitting on the fire-box casing, carrying
four steam cocks and two small wheel valves about the firedoor
level on each side thereof.
A hinged plate appears under the fire door, and on lifting this
there are visible two holes, through the fire-box outer casing,
leading in to the firebox, and equidistant on each side of the centre
line 21 inches apart ; they, are 5 inches diameter and 10 inches
above the grate surface. In each hole is a ring of pipe per-
forated on the front side so as to direct numerous jets of steam
forward into the fire-box. In the latest atomizers this ring
is not employed, the nozzle of the atomizer being enclosed in a
box perforated on the face with several holes through which
154
APPLICATION TO LOCOMOTIVE BOILERS 155
the spray jets issue at converging angles. These cause an
induced current of air. In the centre of each of the rings
is the nozzle of an injector. These are steam worked and inject
oil into the fire-box, mixed with air, which enters at the rear of
the injectors by an india-rubber hose connexion from the
vacuum brake if this is used.
The steam inlet to each injector is on the inside, steam com-
ing by a single pipe, which branches off by square turns right and
left to the injectors. Oil enters by separate pipes worked by
two independent regulating wheel valves, which stand above
the footplate at the fire door level. Each valve is thus inde-
pendently adjustable, but both can be worked together,
instantly to open and close, if necessary, at stations and other
stops. Otherwise the oil apparatus is controlled from the four
cocks mentioned above. One turns steam on to the injector
supply ; another, by right and left branch pipes, turns steam
to the air injecting rings ; and a third admits steam into a
warming coil in the oil tank for the purpose of bringing the oil
to a state sufficiently liquid to flow freely, and to be sprayed suffi-
ciently fine. The fourth serves to blow back steam through the
oil fuel pipes to the tank to clear any obstruction or to blow back
oil which has cooled in the pipe or to warm the pipe, and to
blow through the oil passages of the injectors.
The mode of working is as follows : the engine comes up
from the shed with the light coal fire with which steam has
been made. It is clear and red, the fire-brick arch well heated,
and the fire made up with brick lumps as usual. When de-
sired to burn oil, steam is first set blowing through the injector.
The delivery of the injectors is directly forwards and sideways,
the nozzle having two orifices. No oil is sent against the fire-
box sides, but only towards the brick arch and towards the
middle of the box, the two inclined jets approaching each other.
After the steam is turned on, the oil admission valves are slowly
opened and the oil is sprayed and ignites at once, the whole
firebox being filled with a dazzling white flame.
There is now smoke at the funnel from insufficient air supply.
This is instantly checked by turning steam into the ring jets
which draw in a further large quantity of air through the five
inch openings, and smoke can be reduced to any extent down
to nil. This is a specially valuable feature in economy, for,
while it is so desirable to prevent smoke, it is equally unde-
sirable to admit too much air, and this can be regulated to a
nicety, merely enough air to stop the smoke being injected, or
even only enough to reduce the smoke to an occasional sus-
picion of it. There need be no waste due to excess of air.
156 LIQUID FUEL AND ITS APPARATUS
The light coalfire is kept going by an occasional shovel of
coal.
Though the apparatus is simple, if it were possible for it
to be put out of order in the middle of a trip, the fireman
would commence to shovel coal upon the existing bed of fire,
and the engine would run as an ordinary coal burner without
a hitch or stoppage.
On a trip, if steam is high, the injectors can be instantly
stopped on arriving at a station, or, if the steam is low, con-
tinued at full blast as when running, and the fire kept up to a
maximum efficiency, and steam got up during the wait. There
is less dependence on the blast pipe, and a variable blast nozzle
is used, the simple movement of a lever in the cab swinging a
hinged cap over the pipe top and reducing the nozzle from
5J to 4 1 inches diameter for coal burning.
Should any oil travel unburned so far as the brick arch,
and even run down it, it cannot travel over the firebrick pro-
tection of the lower tube plate without vaporization and com-
bustion, hence this protection, which is the one slight difference
from common practice, a difference, however, of no importance
or injury to the engine's coal burning properties.
There is no projection of any oil upon the fire-box sides,
neither is there local intense combustion to produce local plate
wasting. On the contrary, the whole interior of the fire-box is
filled with flame, and no special ignition point, or rather, com-
bution area, is apparent. Heating is therefore general, and
temperature even.
Though nominally a pound of oil has not the steam making
power of two pounds of coal, nor perhaps could it be shown to
have on a prolonged test ; yet in practice, one pound of oil is
found to be equal to double the quantity of coal, owing to the
facility of regulation and the saving at the safety valve and of
the back pressure from reduced blast pipe resistance. Oil has
the advantage of cleanliness and reduced labour all round, for it
makes no unconsumable refuse, requires no stoking beyond
the keeping up of the small bed of coal fire, which seems to
be a good system where liquid fuel supplies are doubtful in
quantity and uncertain in price, over any system of oil burning
which rejects coal entirely.
In the ordinary work of the Great Eastern Railway the run
between London and Cambridge about 56 miles was made
with one firebox full of coal made up ready for the run and un-
touched. This brought the train to its destination, and if it
were known that the engine would be shedded at once the
steam might be pretty well reduced and the fire left to finish
APPLICATION TO LOCOMOTIVE BOILERS 157
nearly dead. Here came in the advantage of liquid fuel. Even
if steam was down and the fire nearly out, the turning of a
1 andle or two would put the engine in readiness to take out any
train in five minutes after notice, and thus an engine may be
worked to the economy it would be if about to be shedded, and
yet be ready for a full-power run almost instantly.
For lighting up, however, the fire started in a clear grate, as
usual, and the month's average of fuel, including lighting up,
was 12-2 pounds of oil per mile and 11 pounds of coal, or a
total of 23-2 pounds of fuel. Nine other engines of the same
class and the same range of duties averaged 34 pounds of coal
per mile for the same month. Thus one pound of oil was
practically equivalent to two pounds of coal.
Mr. Holden states that for oil burning to be a success, the
apparatus must be independent of any firebox alterations, or
of anything which would prevent instant return to coal or
solid fuel, or its use in Lighting up. Hence his special injector
to spray the oil without the use of special brickwork, hitherto
common as a means of giving an extended hot surface. The
several small ring jets which converge on the jet of oil, both
spread and mix it with air and diffuse the flame, so preventing
local heating.
The injector, of gun metal, is clearly shown in section in Fig.
23. Oil enters at the side some way back of the steam nozzle
and outside this. Steam, therefore, comes inside a thin ring of
oil at the mixing nozzle and through the inner tube comes the
vacuum brake air which, expanding as it becomes heated, still
further aids the breaking up of the oil into spray. The ring
jets of steam induce a further supply of air on the exterior of
all, and so is obtained an alternation of air, oil and air, which
promotes admixture and thorough combustion. The inside
of the injector is removable and can be replaced with
a spare set in a few minutes when running. Removal of
the brake hose connexion allows the injector nozzle to be
cleared by a wire while actually at work, this being the main
reason of the through passage which has been utilized also
for the purposes of the vacuum brake. The latest atomizer is
that of Fig. 24 (1911). Compared with Fig. 23 and 25 it shows
how comparatively little change has been made in the last
nine years. The new pattern is found to use less steam.
The ring jets of this pattern (Fig. 25) seemed to use a good
deal of steam.
In the newest pattern (Fig. 24) there is a small box end enclos-
ing the nozzle, and the flat end of the box has seven perfora-
tions inclined to each other so as to give a converging jet. The
158
i ill CD Hi?
!.:a~'-
160 LIQUID FUEL AND ITS APPARATUS
oil, air and steam are mixed in the box and issue together.
Small supplementary steam jets issue from small holes as
shown at the base of the nozzle box.
The brackets of the oil regulating valves are movable verti-
cally. The two brackets are connected to a hand wheel common
to both, and dropped by a single movement of the wheel, thus
shutting off both oil valves and putting them again in action
without varying their individual adjustment. Later arrange-
ments differ somewhat, the combined motion being given by a
lever, as in Fig. 26.
This lever is used for the station stoppages, after which each
injector can be set going again exactly as before the stop, so
dispensing with fresh regulation.
Seciitn A 3 Section C D
'Fig. 25. ATOMIZER. OLD FORM, H.OLDEN SYSTEM.
In locomotive work, the absence of a bed of incandescent
fuel on the grate is a cause of very serious temperature range
in the firebox when the oil is shut off at stops. Where a solid
fire is maintained on the combined system, there is always an
incandescent fire to prevent undue cooling when the oil is
stopped, and this is a valuable feature apart from the question
of lighting up in the ordinary way and the power of using
solid fuel if necessary at any time so to do.
Fig. 24 is the latest form of atomizer.
The valve B used for regulating the flow of the oil fuel is of
special construction, found desirable after many attempts with
different forms of cocks and valves. To pass regular quantities
of thick viscous fluid through the " crooked passage " formed
by the half open plug of a common cock is impossible, and
some form of " Straightway " valve is necessary. In the
162 LIQUID FUEL AND ITS APPARATUS
example, a small reservoir of oil is formed by the body of the
valve, and a tube with a slit in it is moved up and down inside.
The proportion of cut exposed in the oil reservoir regulates the
supply. With this valve very fine adjustments in the flow of
oil are possible.
The Holden apparatus is now largely used on stationary,
locomotive and marine boilers, but its application on English
railway work has been reduced by the comparative scarcity of
oil since the demands of the Navy have absorbed so much. In
short, liquid fuel is not yet produced to supply the demand.
In Fig. 27 is shown the firebox, about 8 feet long, of an
American locomotive. The tube plate and sides are lined with
brick, and there are two air inlets at the bottom of the box
opening into the ash pit, which has the usual front and back
dampers. In these narrow boxes there is only room for one
atomizer. Oil alone is intended to be used in this furnace, and
the area of brickwork is necessarily larger than in the mixed
system, where the bars are covered with more or less self-
incandescent fuel. The fire-brick arch, but slowly adopted
in American coal burning engines, is of necessity a part of the
oil burning furnace. In some locomotives there is also a small
arch over the atomizer to protect the fire door. In certain
locomotives with still longer boxes there will be a wall of
brick about 6 feet in front of the atomizer, and the arch springs
from this wall, so that there is a 'combustion space between the
wall and the tube plate.
With Texas oil the Great Eastern locomotives, class 1900,
have hauled fast trains on a consumption of 24-7 pounds of
coal tar per mile plus 9-6 pound of coal for lighting up, etc., as
against 40 to 45 pounds of coal. On a test run with a train of
620 tons a four-coupled passenger engine consumed 31 pounds
of Texas oil per mile. These engines were fitted with air heating
arrangements. On the Japanese Government railways, Borneo
oil on the Holden system showed an evaporation as high as
14-42 and averaged 12-6 the year round as against 6-4 pounds
for coal.
An important item is the lengthened life of the internal fire-
box. After some service the sides of an ordinary firebox
present a series of convex surfaces between the stays, which are
subjected to abrasion by the small ashes, sparks, etc., drawn
from the fire by the action of the blast. As a result of this
wearing away of the surface of the plate, it gradually be-
comes thinned, and eventually cracks develop between the stay
holes, with the consequence that the box must be patched
or renewed after a comparatively short existence. With oil
APPLICATION TO LOCOMOTIVE BOILERS 163
fired engines an extension of time of some 50 per cent, can be
secured, as no such destructive action exists. These remarks
on abrasion apply equally to the tubes, smoke box, chimney,
etc., and the economies in this direction are of considerable
value when large numbers of locomotives are affected.
Slope
Slope
Buiner
Fig. 27. FIREBOX OF AMERICAN OIL-BURNING LOCOMOTIVE.
With oil burners the fire is of equal intensity, and as clean
at the end of the day as at the start, and an engine can be run
indefinitely as regards the fire.
The average life of copper fire-boxes of five G.E. Rly. engines,
164 LIQUID FUEL AND ITS APPARATUS
No. 754 to 758, with coal, was found to be 5| years, and that
of two other sister engines, No. 760 and 765, using liquid fuel,
was respectively 8 years 4 months and 8 years.
In fitting these burners to ordinary stationary boilers they
are connected by means of pipes to a hinged joint or trunnion so
arranged that when the burner is swung out of position, the
supplies of steam and oil are cut off, so as to prevent the risk of
fires in the stokehold.
Where, as often the case, oil contains water in such quantities
as to extinguish the fires there is considerable danger. The oil
following after is if the furnace temperature is sufficiently
high violently exploded, or, if the furnace is allowed to become
too cold, the oil falls through the ashpits and on to the stoke-
hold floor, where it spreads out into a thin film probably at a
temperature approaching the flash point, and therefore in a
highly inflammable state.
The specific gravity of most fuel oils being 0-86 to 1 the rate of
settling at low temperatures is very slow, but the difference
in the specific gravity becomes much more marked if the
temperature is raised, and very usual practice has been to heat
up the whole contents of the oil bunker to such a temperature as,
without approaching the flash point of the oil, will make the
density difference sufficient to accelerate the settling.
The objection to this is that a large amount of heat is required,
the radiation surface of a bunker of any size being considerable ;
the heating process is slow, and unless completed before any
of the contents are drawn off, the lower layers of the tank will
consist either of pure water or oil with a large percentage of
water mixed up with it.
To obviate this, a floating suction is used consisting of a long
pipe pivoted upon the side of the bunker or tank, and guided
in the vertical plane by means of a tee or angle iron set to
correct radius.
The suction pipe has a smaU steam-pipe led along its side,
which terminates in a coil immediately below the suction open-
ing. The steam passes through this and heats the oil immedi-
ately below the orifice, and this oil rises into the pipe and leaves
the water behind. The float is proportioned and arranged to
keep the mouth of the pipe about 6 inches below the level of
the oil in the tank.
This apparatus is certain in action and requires but little
heat, since this is only applied to that portion of the oil immedi-
ately under the mouth of the suction pipe, and there is little
radiation from the bunker side, and the heated oil at once
moves off to be used while still hot.
About 20 barrow loads make one cubic yard. An ordinary cart
holds about ||- cubic yard.
165
166 LIQUID FUEL AND ITS APPARATUS
Fig. 28 shows the application to a locomotive with fire-box
3 feet 4J inches wide. For a smaller fire-box one atomizer only
is necessary.
The apertures in the fire-box are made by screwing a copper
ferrule into the tapped plate and beading over at the ends ;
into this is drifted a wrought iron ferrule, which makes a per-
fectly tight joint.
The nozzle of the atomizer is placed about J in. above the
centre of the aperture, and the face of the ring f inches from
the front of same.
When liquid fuel is used alone, steam is first raised in the
boiler by a wood and a coal fire to 25 pounds or 30 pounds
pressure, the fire is levelled and covered with a layer of broken
fire-brick of not more -than 3 inches cube, spread thinnest
about the centre of the fire-box, and well packed round the
sides and corners. A few pieces of waste or wood are thrown
in to cause a flame before the fuel is introduced.
An air heater formerly was used, but has been abandoned in
recent practice.
The regulating gear is so arranged that a simple movement
of the lever closes both oil valves without affecting their
separate adjustment when open.
CHAPTER X
LIQUID FUEL APPLICATION TO STATIONARY AND OTHER BOILERS.
The Lancashire Boiler.
FIG. 29 shows the arrangement of Holden's Burners on
a Lancashire type boiler. The burners are placed at the
front of the brick lined extensions, to which heated air is con-
veyed from large tubes passing down the outer flues. The
fire-brick construction is simple and easily introduced for an
ordinary sized boiler with a grate of, say, 7 feet long. A strik-
ing bridge pillar with inclined face is built up about 2 feet
6 inches inside the furnace ; next, a screen with large clear
opening about 1 foot 6 inches behind the former ; and finally,
a second screen with oblique perforations to direct the gases
along the inner surface of the flue. The central portion of this
last screen is recommended to be built solid. On boilers thus
arranged, with fair working conditions, an evaporation of from
14 to 15 pounds of water per pound of Texas fuel oil (from and
at 212F.) is readily obtained.
On a large boiler of this type burning north country " smalls "
and evaporating only 6-5 pounds of water per pound of coal,
the Texas fuel oil has secured an evaporation of 15-25 pounds of
water per pound of fuel.
If desired the fire bars are left in and covered by a layer
of fire-brick or chalk as a base for the fire in case it may be
necessary to return to solid fuel at any time. Any internally
fired boiler may be treated by either method. Where the
bars are left in there ought to be a damper fitted to the opening
of the ash-pit to regulate the admission of air.
In these furnaces the injector is placed about 8 or 10 inches
above the grate surface and about J inch above the centre of the
4-inch opening cut through the furnace door. The injector
is inclined so as to point to the second or third brick from the
top of the bridge. Dry steam, perferably superheated, is
admitted.
Generally, in the firing of internal furnace boilers, the fuel is
blown in parallel with the grate surface and 8 to 10 inches
167
168
ino
170 LIQUID FUEL AND ITS APPARATUS
above it. In the large vertical boiler the atomizer is usually
placed below the fire-door opening, but in small vertical boilers
it must be placed through the door. In either case the opposite
half circle of the furnace must be lined with fire-brick to the
height of about half the furnace diameter to form the necessary
incandescent surface on which any unburned oil can strike.
The Water Tube Boiler.
For the water tube boiler without grate bars the arrangement
of Fig. 30 is employed, there be in 3; an additional arch of fire-
brick brought forward from the bridge to prevent too early a
passage of the gases among the tubes. The author would
extend this (and also the first arch) further than shown in Fig.
30 ? it being impossible either with coal or oil to secure smokeless
results where the hydrocarbon gases
,,<J^ I pass too quickly among cold tubes.
/',/^ f ' Nor is there space and time for such
//'"/' complete combustion as is desirable.
The steam blast may be made less
intense when oil fuel is used by the
Mac Allan movable cap (Fig. 31).
This is folded over the blast pipe
orifice, which it reduces from 5 J to 4|
inches diameter.
The position of the atomizer is
important. If too high the combus-
tion is vibratory, and an intolerable
humming sound is produced by the many rapid explosions due
to non-continuous combustion. The oil fire must be along the
plane of the coal fire for the best results, and not too high
above it.
Owing to its large proportion of hydrogen, the production
of carbon dioxide is less, and this is held to be an advantage
of liquid fuel for working tunnels, and the Arlberg tunnel was
so worked by 32 engines. It must not, however, be over-
looked that hydrogen destroys three times as much oxygen
as is destroyed by a pound of carbon, and produces but little
more calorific effect per pound of oxygen consumed, so that
it is equally destructive of the vital properties of the air and
introduces an excess of nitrogen in place of an excess of carbon
dioxide. The physiological effect of the carbon dioxide is less
to be feared than the absence of oxygen which it implies.
Too much, therefore, should not be made of this supposed
advantage of liquid fuel, the danger being due to the absence of
Fig. 31. MACALLAN VARI-
ABLE BLAST CAP.
APPLICATION TO STATIONARY BOILERS 171
oxygen. The Arlberg tunnel is now electrically worked.
No very large installations have been made lately, owing to the
difficulty in obtaining a large and continuous supply of oil at a
price low enough to meet the competition of coal. But many
heavy locomotives have been fitted for special work on moun-
tain sections with many long tunnels, as on the Italian State
Railways. It is particularly desirable to avoid smoke in
tunnels.
Locomotive Boiler.
Fig. 32 is the fire-box used for liquid fuel on the Southern
Pacific Railroad, the oil being sprayed into the front of the fire-
box below the mud ring and under the usual brick arch and
directed against a sloping brick lining of the back plate. The
sides of the box are
cased in bricks, and
there are openings
for air in the brick
bottom to admit air
under the flame. A
central brick arch
baffle is thrown
across the middle
of the fire-box, and
an arch is thrown
across just below
the fire-door. The
plates of the upper part of the box are bare, and the results
are said to be satisfactory.
According to Mr. Holden the fuel tank should be above the
level of the atomizers. This is a point with which all do not
agree ; some consider that the fuel ought to be pumped to
the atomizers, and no oil should be able to flow by gravity
with the attendant risks in case of rupture.
Unless an independent source of steam is available, steam
should be raised in the boiler by an ordinary fire to a pressure
of, say, 25 pounds, when the liquid fuel apparatus may be
started.
Oil burners must not be started before there is a flame in the
furnace ; if doubtful, a few pieces of wood or some oily waste
should be set alight in the furnace before applying the oil.
The above rules are applicable to all systems of oil burning.
A common danger is the risk of gases accumulating in the fur-
nace and leading to explosion when the dampers are opened
and flame produced. As with coal, the accumulation of gas
Fig. 32. LOCOMOTIVE FiRE-Box FOR OIL FUEL
SOUTHERN PACIFIC EAILROAD.
172 LIQUID FUEL AND ITS APPARATUS
may be prevented by drilling a two-inch hole near the top of the
damper, so that when the damper is closed there is always a
vent through it which will stop any accumulation of gas.
The atomizing agent, whether steam or air, should be hot ;
high pressure steam is better than low pressure steam ; the
tendency is to force the oil forward at a considerable pressure
to the burners and compel it to escape, by a fine opening, there-
by probably tending to atomize itself somewhat.
The practice in America generally is towards pumping oil
to the burners rather than allowing it to flow by gravity.
Air at a moderate pressure appears to be as competent to
atomize oil as steam at a high pressure. No explanation of
this is given, but it is partially due to the greater density of air
and probably in part to the fact that air is a supporter of
combustion and induces earlier combustion or ignition.
The Meyer System.
This is shown in Fig. 33, and is a modification of the Korting
system. Oil is supplied by the Korting system and air is ad-
mitted through specially placed blades in an extension of the
furnace front, the air being heated in a surrounding jacket,
which is arranged with spiral divisions. The air is delivered
to the surface in a whirling manner, and the system has been
at work on several Dutch steamers with success and similar
general types of apparatus have been running in Roumania.
THE MIXED SYSTEM OF COAL AND LIQUID FUEL COMBUSTION
There is more in the mixed system than mere convenience.
The simultaneous use of solid and liquid fuel in the same furnace
modifies the conditions for each.
For coal the efficiency of combustion is better ; for oil the
heat is better utilized.
Combustion on the grate may be imperfect, but the oil
atomizer so mixes up the gases from the grate with the air
admitted through and above it, that combustion is much
improved and the excess of air is used by the oil.
Where the oil is only a fifth of the coal, the coal equivalents
of the oil appears enormous.
According to M. Bertin, where 5 kilos, of coal would ordinarily
develop each 7,800 calories, they will produce 9,200 calories, a
gain of 7,000 calories. The excess of air supplied with the 5
kilos, of coal would be 20 cubic metres, and this would suffice
for the added kilogram of oil, which would produce 11,000
178
174 LIQUID FUEL AND ITS APPARATUS
calories with no further air supply. A total of 18,000 calories,
compared with the original output of 7,800 calories per kilo,
of coal, makes the ratio of oil to coal appear 2-31. Obviously
a part of this is due to coal, but it may fairly be credited to the
system.
The limit of perfect use of air is found when the oil is one-
third of the coal, and the ordinary four cubic metres of excess
air still furnishes the theoretical 11 cubic metres for the oil :
the apparent equivalence of coal and oil becomes
1,400 x 3 + 11,000 _, _
7,800
These ratios are not perhaps secured in practice, but serve
to point to the possible advantages of the mixed system and
what should be aimed at.
With half and half coal and oil the ratio becomes 1-77,
a figure that has been approached in certain experiments at
Indret. Ratios of 3 and over, what have been claimed, cannot,
as Mr. Bertin says, be justified on any hypothesis. Nor is the
total consumption of the oxygen supplied at all closely ap-
proached in general practice.
The proportion of free oxygen to carbonic acid is an indi-
cation of the excess of air admitted. The ratio of the air ad-
mitted to that used is
CQ 2 + Q
C0 2
C0 2 +
- = 1 + j^r- per volume, and
20-8
These figures neglect the hydrogen.
With coal burned at the rate of 100 kilos, per metre 2 of grate,
if the oxygen measures 8 per cent., and with 200 kilos., say
5 per cent., the fire is too thin or the draught too great. With
1 or 2 per cent, of carbonic oxide the fire is too thick and the
draught poor. Both oxygen and CO present together indi-
cate bad furnace arrangements.
A test at Indret of the trial boiler of the Jeanne d'Arc with
coal alone gave the following results
Coal per hour
per metre a of
grate.
Percentage in volume.
I *T&
C0 2 .
CO.
0.
N.
90k.
11
1
6
82
1-54
140
11
1
5
83
1-45
200
13
0-5
4
82-5
1-30
APPLICATION TO STATIONARY BOILERS 175
The same boiler on the mixed system gave the results below
Per hour per metre 8
of grate.
Air
Pressure.
Percentage of Gas.
'+W
Carbon.
Petroleum.
C0 2 .
CO.
0.
N.
^KU \
37k.
10 mm.
10
8
82
1-80
/OK. <
30
10
10
8
82
1-80
37
10
10
8
82
1-80
50
20
8-5
9-5
82
2-12
66
25
8-5
9-5
82
2-12
(
35
25
11
7
82
1-64
150 \
55
30
11
7
82
1-64
I
75
40
11
7
82
1-64
With oil alone Mr. Orde found as below
CO 2 .
CO.
0.
N.
' + <
Test No. 1
Test No. 2
13-2
12-6
3-6
4-0
83-2
834
1-27
1-3S
Average
12
3-8
83-3
1-285
a better result, after all, than the mixed system produced.
In calculating the apparent effect of mixed fuel, M. Bertin
assumes the case of a boiler working 1 hour and a weight of water
a per kilo, of coal ordinarily,
b = the water evaporated per kilo, of mixed fuel,
x = the evaporation attributed to one kilo, of oil,
C = weight of coal burned per metre 2 of grate,
j> on ,, ,, ,, ,, ,,
The vapour produced by C + D of mixed fuel, assuming a
to be as in the ordinary coal fired boiler, will be Ca + Do;.
Then per kilo, of mixed fuel we have
Ca + Vx (C + D)6-Ca , , C
' C ^ D = &, which gives x = -~- =6 -f-jy(6-a),
Whence, if R is the ratio of oil to coal, we have
a
a
Tests in the Furieux made to determine R gave the following
results
D
x
C
a
x
R=_
0-00
9-05
0-45
9-05
11-34
1-25
0-64
9-05
14-2
1-56
176 LIQUID FUEL AND ITS APPARATUS
The figure 1-56 was greater than the figure found for oil
used alone, but was not confirmed by tests at Cherbourg of a
Godard boiler with too forced a draught and badly arranged
oil sprays, for the effect b of the mixed fuel was even inferior
to that of coal alone, which shows how much the efficiency
depends on arrangements.
The value of R was sought at Indret by Mr. Brillie in a series
of tests extending from the end of 1896 to early in 1900, in view
of applying mixed firing to boilers of Du Temple Guyot type.
The atomizers had air induction passages as in the Orde
atomizer, Fig. 15, but no air heating. The flames kept short
and the heat kept well in the furnace, and high values of R
were reached, as 1-6 for a rate of combustion of 100 kilos, of
coal and 50 kilos, of oil per metre 2 of grate. 1
The tests, however, were too short for exactitude.
Other tests made only upon engine power are, however,
available.
Let c be the coal per horse power ordinarily.
e in the mixed system.
d
oil
Then d takes the place of c e in the production of one
horse power so that
T> ,
c e
The following table is a resume of Navy tests on the loco-
motive type of boiler or torpedo boat No. 109 at Cherbourg.
1st Series.
2nd Series.
3rd
Series.
Air pressure. .
Coal alone ....
h.
c.
15mm.
1,337k
13mm.
1,337k
12mm.
1,337k
25mm.
1,354k
26mm.
1,354k
29mm.
1,354k
50mm.
1,506k
/ Coal ")
e.
979
914
581
713
721
652
1,219
Mixed 1 p e t ro i m< !
d.
379
388
494
405
474
655
434
ys em (^otal je+d
1,358
1,302
1,075
1,118
1,195
1,307
1,653
Equivalent =R =5 1
0,94
1,09
1,53
1,58
1,33
1,07
0,66
The interest lies in the falling off at high pressures, the
furnace being too short satisfactorily to burn the oil at such
rapid draught.
Where 60 kilos, of oil were used to 80 kilos, of coal with draught
but little forced, R was found to be 1 -5, and the mixed system
took the place of forced draught, with a result equal to the
combustion of 170 kilos, of coal only, a result thought very
encouraging. Very discordant results were obtained on the
1 Kilos, per metre 2 -^ 5= pounds per square foot nearly.
APPLICATION TO STATIONARY BOILERS 177
Milan, the Surcouf, the Pakin, and the Forbin. On the Milan
especially oil proved very unsuitable to the furnaces of the
Belleville boiler, as might be anticipated. On the Surcouf,
on the contrary, the result of mixed fuel was to reduce total
fuel consumption nearly to half that of coal alone.
M. Bertin does not express any final opinion on mixed sys-
tems, but claims that where employed it is essential to success
that all the details should be simple so as to avoid the danger of
error on the part of a little-trained personnel, such as the open-
ing or closing of certain valves, always in their power to do.
Generally little information is public on liquid fuel in any
Navy. Nobody knows why a secret is made of it, for the
efficiency attained with liquid fuel outside naval practice is
such that better results are scarcely likely to have been attained
within it.
CHAPTER XI
RUSSIAN AND AMERICAN LOCOMOTIVE PRACTICE
The Baldwin Co.'s System.
THE Baldwin Locomotive Co. consider that, while opinions
upon atomizers differ as to central jet burners such as
the Urquhart, the relative position of the oil supply and other
details, their own burner (Fig. 34) is a satisfactory one, and
has been applied to many locomotives in Russia and the
United States.
It is rectangular in section, with two longitudinal passages,
the upper one for oil, the lower one for steam. The oil is
regulated by a plug cock on the feed pipes, the handle of which
extends to the cab within easy reach of the fireman.
Steam is admitted to the lower part of the burner through a
pipe so connected to the boiler as to ensure dry steam. The
control valve is in the cab close to the fireman's seat. A free
outlet is allowed for the oil at the nose of the burner ; the
steam outlet, however, is contracted at this point by an ad-
justable plate which partially closes the port, and gives a thin
wide aperture for the exit of the steam. This wire-draws the
steam increasing its velocity at the point of contact with the oil.
and giving a better atomization. A permanent adjustment of
the plate is made for each burner after the requirements of
service are ascertained. The moving of the plate is not then
required except for cleaning purposes. The oil, as it passes
through the burner, is heated by the steam in the lower portion,
and flows freely in a thin layer over the orifice. It is there
caught by the jet of steam and completely broken up and ato-
mized at the point of ignition, and carried into the fire-box
in the form of vapour, where it is thoroughly mixed with air
and burns freely.
It is computed that one inch of breadth of slit will serve for
100 square inches of cylinder area, so that the breadth of a
burner is B = D 2 x -007854. As only one burner is used,
178
AMERICAN LOCOMOTIVE PRACTICE 179
Fig. 34. ATOMIZER. BALDWIN LOCOMOTIVE Co.
American fire-boxes being narrow, it is apparently the case
that one cylinder is intended to be taken, and not the area of
both cylinders. D = diameter of cylinder.
Large oil-pipes deliver a full supply as far as the regulating
cock, to permit of fine , ,
adjustment of which its
orifice is not circular
but square, with the
diagonals as in Fig. 35.
The necessary changes
to fit an engine to use
liquid fuel are shown in
Fig. 36. The atomizer Fig 35 OlL REGULATING CocK .
is attached below the BALDWIN LOCOMOTIVE Co*
mud ring, and the spray
is directed upwards into the fire-box, which is fitted with a
brick arch, a liner of fire-brick and a base filling the front
180
181
182 LIQUID FUEL AND ITS APPARATUS
half of where the grate usually is placed. A small hearth
is placed to catch any drip from the burner, and from the
lower corner of the bridge there is built, to protect each side
sheet, a triangular wall of bricks extending with its lower point
to the back plate. The side walls form the sides of the fire-
brick combustion chamber. The " ash-pan " is retained with
its air dampers to admit air below the fires, and the dampers
should shut tight. The inner side of the fire-door is lined with
a plate of fire-brick.
The latest form of fire-box (1911) is that of Fig. 37. This differs
but little from that of Fig. 36, which represents a coal fire-box.
The arch is kept low and the upper space of the box is large.
It is recommended not to leave too little space between the
arch and the crown sheet ; otherwise the flames will be too
severe upon the crown sheet and generate too severe a local
heat. The ashpan is of modified form as shown. The weight
and volume of oil for a given mileage will be about half that
necessary for coal.
A report of the Committee of the American Railway Master
Mechanics' Association says
Fuel oil can be used in almost any form of fire-box, the best
place for the burner being just below the mud ring, spraying
upward into the fire-box. In some recent experiments with
oil of 84 gravity, 140F. flash, and 190F. fire test, in which
the boiler had 27 square feet grate area and 2,135 square feet
of heating surface, 8 per cent, being in the fire-box, it was found
that there were about 39 pounds of oil burned per square foot
of grate area, about 0-45 pounds per square foot of heating
surface per hour, the equivalent evaporation from and at 212
being about 12 J pounds of water per pound of oil. It was also
computed that there should be about one-third of an inch
width of burner for each cubic foot of cylinder volume.
Or volumes of both cylinders in cubic feet -f- 3 width of
burner in inches for ordinary locomotives. For compound
engines the amount of steam is 10 per cent, and of fuel 20 per
cent, less, and in the foregoing formula only the h.p. cylinder
volume ought to be considered.
For compound locomotives a guide to an approximate idea
of the value of oil fuel as compared with coal is as follows :
Cost of coal per ton (of 2,000 Ib.) +cost of handling (say 50 cents)
X 10-7 X 7
2,000 x evaporative power of coal
= Price per American gallon at which oil will be the equivalent
of coal. To find the price per English gallon multiply by 1 -2.
AMERICAN LOCOMOTIVE PRACTICE
183
In these computations the cost of both oil and coal is con-
sidered at the engine, and not at the place of purchase.
The weight and volume of crude petroleum based on a
specific gravity of 0-91, which is about the average of the Texas
oil, as well as that received from South America, is given below.
WEIGHT AND VOLUME OF CRUDE PETROLEUM.
Pound.
U.S. Liquid Gal.
Barrel.
Gross Ton.
Imp. Gal.
1
13158
0031328
0004464
1096
7-6
1-00
02381
003393
83
319-2
42-00
1-00
1425
35-00
2,240-0
294-720
7-017
1-00
245-60
For convenience in obtaining the correct approximate weight of
oil, the gravity conversion table, No. XIV, may be useful.
In American practice where railroads are so dirty with ash
and cinders thrown from the locomotives by the powerful blast
employed, oil should give an advantage to any line adopting it
that cannot be so securely counted on in Great Britain, where
a,sh throwing is less prevalent.
Oil puts a stop to the choking of the tubes of the boiler and
permits tubes to be employed smaller than now admissible on
account of liability to choke.
Tubes of one inch diameter might be used if enough could
be got in to give the requisite area.
The economy of oil is not merely a question of fuel economy.
Table No. XI gives the economy of oil at its relative value
compared with coal on both the fuel account and all ascertained
economies, the second value being based on 1 pound of oil
being worth 2 of coal in place of If, as on the mere fuel account.
The extra economies include repairs on locomotives and ash
handling.
Dr. Dudley's formula for relative price is
P price of oil per barrel.
W= weight per gallon in pounds.
2,000 X P _ r . , N = gallons per barrel.
W X N X R R = ratio of oil to coal = If or 2,
according to conditions.
C price of coal per ton of 2,000.
For tons of 2,240 Ib. use this number in the numerator in
place of 2,000. The weight W multiplied by N will be the same
in either American or English gallons, and the barrel is always
the same, so that only the pounds per ton need be changed,
184 LIQUID FUEL AND ITS APPARATUS
the price of coal and oil of course being given in the same
equivalents, either dollars or shillings.
W x N x R x C
~ 2,000 (or 2,240 for long tons).
The Baldwin Co. do not recommend crude oil : it is more dan-
gerous ; it has an exceedingly unpleasant odour, and it is not
so economical. Crude oil contains more or less volatile matter
which vaporizes quite readily. With the necessary use of
lanterns and open lights round about locomotives, there would
be more or less danger of explosions. In the case of a wreck,
if the oil tank was ruptured, it would be almost impossible to
prevent a fire. As to the odour of the crude oil, it would cer-
tainly be extremely unpleasant to ride behind a locomotive
fed with Lima crude oil. Crude oil is not so economical as
reduced oil, because oil is sold by volume, and a gallon of crude,
instead of weighing 7-3 pounds, weighs from say 6-25 to 6-5
pounds, and, as the heat is proportionate to the weight, a barrel
of crude will not give so much heat as a barrel of reduced oil.
The oil used on the Grazi-Tsaritzin Railway, and believed
to be quite safe to use, is an oil not below 300F. fire-test.
Crude oil can be used on stationary boilers, where it is kept in
tanks and brought to the boilers in pipes.
The arguments appear sound, in view of the disastrous Ameri-
can experiences of burning railway wrecks, and the English
experience at Abergele ; but all crude oils are not so unpleasant
as the Lima oil referred to, and the odour should not live
through the furnace. Still the fire risk of crude oil, with its
volatile constituents left in, is to be avoided.
In experiments on the Pennsylvania Railroad, it was found
with oil at 30 cents per barrel, that it cost nearly 50 per cent,
more to take the same train of cars 100 miles by means of oil
than by means of coal.
The Urquhart System.
To the late Thomas Urquhart, of Dalny, Scotland, the former
Locomotive Engineer of the Grazi-Tsaritzin Railway of Russia,
is due the first notable success in liquid fuel combustion. 1
Urquhart brought the system to the notice of engineers in a
paper read at Cardiff in 1884.
According to this paper, the percentage of astatki in Russian
oil is 70 to 75 per cent., while Pennsylvania oil contains but
25 to 30 per cent., the two products being the complement of
1 Proceedings of the Institute of Mechanical Engineers, 1884.
AMERICAN LOCOMOTIVE PRACTICE 185
each other. This fact is quite consistent with approximately
equal proportions of carbon and hydrogen, and Table XII
is given to illustrate this. The following is an abstract of
Urquhart's paper
" Comparing naphtha refuse and anthracite, the former has a
theoretical evaporative power of 16-2 pounds of water per
pound of fuel, and the latter of 12-2 pounds at a pressure of
8 atm. or 120 pounds per square inch ; hence petroleum has,
weight for weight, 33 per cent, higher evaporative value than
anthracite. In locomotive practice a mean evaporation of
from 7 pounds to 7J pounds of water per pound of anthracite
is generally obtained, thus giving about 60 per cent, of effi-
ciency, while 40 per cent, of the heating power is lost. But
with petroleum an evaporation of 12-25 pounds is practically
obtained, giving
12 25
= 75 per cent, efficiency.
Thus petroleum is theoretically 33 per cent, superior to
anthracite in evaporative power ; and its useful effect is 25
per cent, greater, being 75 per cent, instead of 60 per cent.
Weight for weight, the practical evaporative value of petroleum
is at least from
12 25 - 7-50 12 25 - 7-00
7>5Q =63 per cent, to ^ =75 per cent.
higher than that of anthracite.
Spray Injector.
" Steam, not superheated, being the most convenient for
injecting liquid fuel into the furnace, it remains to be proved
how far superheated steam or compressed air is superior to
saturated steam taken from the highest point inside the
boiler, by a special internal pipe. In using several systems
of spray injectors, he invariably noticed the impossibility
of preventing leakage of tubes, accumulation and inequality of
heating of the fire-box.
" The work of a locomotive is very different from that of a
marine or stationary boiler, owing to the frequent changes of
gradient on the line, and the stoppages at stations, which
render firing with petroleum very difficult ; and were it not for
properly arranged brickwork inside the fire-box, the spray jet
alone would be quite inadequate. The efforts of engineers
have been mainly directed towards arriving at the best kind of
spray injector for so minutely sub-dividing a jet of petroleum
186 LIQUID FUEL AND ITS APPARATUS
into a fine spray, by the aid of steam or compressed air, as
to render it easy of ignition. For this object nearly all the
known spray injectors have very long and narrow passages for
petroleum as well as for steam ; the width of the orifice does
not exceed from J mm. to 2 mm., or 0-02 in. to 0-08 in., and in
many instances is capable of adjustment.
" With such narrow orifices any small solid particles which
may find their way into the spray injector along with the petro-
leum will foul the nozzle and check the fire. Hence in many
steamboats on the Caspian Sea, although a single spray injector
suffices for one furnace, two are used, in order that when one
gets fouled the other may still work ; but, of course, the fouled
orifices require incessant cleaning out.
" Locomotives. In arranging a locomotive for burning petro-
leum, several details require to be added in order to render the
application convenient. For getting up steam, to begin with,
a gas pipe of 1 in. internal diameter is fixed along the outside
of the boiler, and at about the middle of its length it is fitted
with a three-way cock, having a screw nipple and cap. The
front end of the longitudinal pipe is connected to the blower
in the chimney, and the back end is attached to the spray
injector. Then by connecting to the nipple a pipe from a
shunting locomotive under steam, the spray jet is immediately
started by the borrowed steam, by which at the same time a
draught is also maintained in the chimney. In a fully equipped
engine-shed the steam would be obtained from a fixed boiler
conveniently placed and specially arranged for the purpose.
Steam can be raised from cold water to 3 atm. pressure in
twenty minutes. Auxiliary steam is then dispensed with, and
the spray is worked by steam from its own boiler ; a pressure
of 8 atm. is then obtained in from 50 to 55 minutes from the
time the spray jet was first started. In daily practice, when
it is only necessary to raise steam in boilers already full of hot
water, the full pressure of 7 to 8 atm. is obtained in twenty
to twenty-five minutes. While experimenting with liquid
fuel for locomotives, a separate tank was placed on the tender
for carrying the petroleum, having a capacity of about 3 tons.
But a separate tank on 'the tender, even though fixed in place,
would be a source of danger from the possibility of its moving
forwards in case of collision. As soon as petroleum firing was
permanently introduced, the tank for fuel was placed in the
coal spaces of the tender between the two side compartments
of the water tank. For a six-wheeled locomotive the capacity
of the tank is 3J tons of oil, a quantity sufficient for 250 miles,
AMERICAN LOCOMOTIVE PRACTICE 187
with a train of 480 tons gross, exclusive of engine and tender.
In charging the tank with petroleum, it is important to have
strainers of wire cloth in the manhole of two different meshes,
the outer one having openings of, say, J in., the inner say of
J in. [In later English practice the strainer is much finer than
this. AUTHOR.] These strainers are occasionally taken out
and cleaned. If care be taken to prevent solid particles from
entering with the petroleum, no fouling of the spray injector
is likely to occur, and if an obstruction should arise, the ob-
stacle, being of small size, can be blown through by screwing
back the steam cone in the spray injector far enough to let
the solid particles pass and be blown into the fire-box. This
expedient is easily resorted to even when running and no more
inconvenience arises than an extra puff of dense smoke for a
moment, in consequence of the admission of too much fuel.
Besides the two strainers in the manhole of the petroleum
tank on the tender, there should be another strainer at the
outlet valve inside the tank, having a mesh of J in. holes.
" In lighting up, precise rules must be followed to prevent
explosion of any gas accumulated in the fire-box. First clear
the spray nozzle of water by letting a small quantity of steam
brow through, with the ash-pan doors open ; at the same time
start the blower in the chimney for a few seconds, and any gas
will immediately be drawn up the chimney. Next, place on the
bottom of the combustion chamber a piece of cotton waste
or shavings, saturated with petroleum and burning with a
flame. Then open first the steam valve of the spray injector,
and next the petroleum valve gently ; the first spray of oil
coming on the flaming waste ignites without any explosion
whatever, after which the fuel can be increased at pleasure.
By looking at the top of the chimney, the supply of petroleum
can be regulated by observing the smoke. The general rule is to
allcw a light blue smoke to escape, showing that neither too much
air is being admitted nor too little. The combustion is under
the control of the driver, and the regulation can be effected
so as to prevent smoke altogether. While running the driver
and fireman should act together, the latter having at his side
of the engine the four handles for regulating the fire, namely,
the steam wheel and the petroleum wheel for the injector,
and the two ash-pan door handles in which are notches for
regulating the air admission. Each alteration in the position
of the reversing lever or screw, as well as in the degree of open-
ing of the steam regulator or the blast pipe, requires a corres-
ponding alteration of the fire. Generally the driver passes the
word when he intends shutting off steam, so that the alteration
188 LIQUID FUEL AND ITS APPARATUS
in the firing can be effected before the steam is actually shut off ;
and in this way the regulation of the fire and that of the steam
are virtually done together. This care is necessary to prevent
smoke and waste of fuel. When, for instance, a train arrives
at the top of a bank which it has to go down with the brakes on,
exactly at the moment of the driver shutting off steam and
shifting the reversing lever into full forward gear the petro-
leum and the steam are shut off from the spray injector, the
ash-pan doors are closed, and if the incline be a long one, the
revolving iron damper over the chimney top is moved into
position, closing the chimney, though not hermetically. The
accumulated heat is
thereby retained in
the fire-box ; and the
steam even rises in
pressure, from the
action of the accumu-
lated heat alone. As
soon as the train
reaches the bottom
of the incline and
steam is again re-
quired, the first thing
done is to uncover
the chimney top ;
then the steam is
turned on to the
spray injector, and
next a small quan-
tity of petroleum is
admitted, but with-
out opening the ash-
pan doors, a small
fire being rendered
possible by the entrance of air around the injector, as
well as by leakage past the ash-pan doors. The spray,
immediately on coming in contact with the hot chamber,
ignites without audible explosion ; and the ash-pan doors are
finally opened, when considerable power is required, or when
the air otherwise admitted is not sufficient to support complete
combustion. By looking at the fire through the sight hole,
it can always be seen at night whether the fire is white or
dusky ; in fact, with altogether inexperienced men, it was
found that after a few trips they could become quite expert in
firing with petroleum. The better men burn less fuel than
Fig. 38. GOODS LOCOMOTIVE, URQUHART
SYSTEM, GBAZI-TSARITZIN RAILWAY.
AMERICAN LOCOMOTIVE PRACTICE 189
others, simply by greater care in attending to the essential
points.
" Several points have arisen which must be dealt with to
ensure success. The distance ring between the plates around
the firing door is apt to leak hi consequence of the intense heat
and the absence of water circulation ; it is therefore protected
by having the brick arch built up against it, or, better still, a
flanged joint is substituted. This arrangement occasions no
trouble whatever."
The fire-box arrangement of the goods locomotive is shown
in Fig. 38. The sprayer points downwards upon the hearth
which is built in the ash-pan, and continuous with the
bridge and arch. A block of brickwork is placed under
the sprayer, and below that is a passage for air. The bridge
is continued up to the crown of the box, but is perforated
and the whole of the front tube plate is exposed to heat. The
fire-box surface is 82 sq. ft. Total heating surface, 1,248 sq.
ft. " Grate " area, 17 sq. ft. Weight, 36 tons in running
order. Pressure, 120 to 135 pounds. 151 tubes 13 ft. 10 in.
long X 2 in. outside diameter.
Fig. 39 shows the petroleum tank in the tender, the heating
coil C surrounding the filter whence the oil is drawn through a
cock V and pipe P to the sprayer. Steam goes by way of the
pipe S and escapes at T. W is the collector for water.
Fig. 40 shows another furnace arrangement, in which the
brickwork of the fire-box sides is made cellular, and air is
admitted also below the sides by lateral openings K with
regulating dampers. The fire-doors are quite blocked, and only
a sight hole left at H.
A later design is that of Fig. 41. This includes a lined ash-
pan, bridge and over-arch, with a passage through it for air
admitted by the forward ash-pan damper. Lateral arches are
provided in order that the side sheets of the fire-box may be
exposed to the heated gases. No part of the fire-box is actually
in touch with the fire-brick, yet the burning oil is completely
enclosed with a brick oven. As very usual in Continental
practice, the engines had the closing cap to the chimney top.
This is used to retain heat in the fire-box at times of standing,
and should be a most effectual damper. With liquid fuel
employed without solid fuel, the closing of the chimney is very
efficient in retaining the heat of the brickwork, and this damper
is used when running down hill, and, on again turning the oil
spray into the furnace it is at once ignited by the hot brickwork.
There is a pointer and scale on the spindle of the regulating
I
I
g
w
p
H
fc
M
J
J
a
5
bfi
190
AMERICAN LOCOMOTIVE PRACTICE
191
valve D for use by night. The Auther has noticed on the
Great Eastern Railway, that when apparently quite dark, the
chimney top can be seen sufficiently to judge of smoke.
The injector is shown in Fig. 42. It consists of a central
steam jet, an annular passage for oil and an outer annulus
for air. The steam jet is regulated by screwing the steam cone
oooooooo
ooooooooo
oooooooo
OOOOOOOO"
ooooooo
oooooooo
oooooo
O o o o o oo -
OOQOOOO
ooooooo
oooooooo
oooooooo
000000000
bC
s
to and fro by a worm and wheel on the regulating handle
and spindle. The steam cone can readily be removed for
clearing purposes, or the back plug can be taken out while
the sprayer is at work, with little delay, a wire being intro-
duced to remove any possible obstruction that the steam will
not discharge.
193
Sprct,y Injector.
OiJ^ ^Sm. Longitudinal, Sec&cm
O 2
Fig. 42. ATOMIZER. URQUHART'S.
193
194 LIQUID FUEL AND ITS APPARATUS
Economies of 45 and 57 per cent, over anthracite and bitum-
inous coal changed to 57 and 67 in an engine arranged to warm
the air slightly, and Urquhart thought the air ought to be
heated, and this is well established as good practice.
The fuel consumption of all kinds appears high, but this is
attributable to long waiting on a single line and to the weight
of trains, often as much as 720 tons, and the exposed country,
with strong side winds.
Consumption of
Coal - fiul lines
Fuel per Train - Mile
PeiroieTzrrL : - Dotted tines
no
100
80
80
70
60
50
40
30
on
JAN.
FEB
MAR.
APR.
MAY.
JUN.
JUL.
AUG.
SEP
OCT.
NOV.
DEC.
110
100
90
80
70
60
50
40
30
">n
>
^
%
*
\
/
A-
A
*^
A\
\
A
V
"^
-~"
ts
\_
-^-
^^
*
-S
B
1
V
1 *
^
/
J-
L
^
^
V
^
^
^
.S
)
^
-.B
Jr
*
\
^
&
tx
e*-^
^Jfc;
^
__^.
.5-
b
A (roods Engme, 8 whe.tls cvupled. Goods Train
BB . 6
C Mjced 4- . , Minced .
DP 4 'Passenge* .
Fig. 43. LOCOMOTIVE PERFORMANCES WITH COAL AND OIL FUEL.
URQUHART'S SYSTEM, GRAZI-TSARITZIN RAILWAY.
Considerable space has been given to this system and to the
figures and drawings, because though now old and dating back
nearly 30 years, Urquhart had the correct principles of combus-
tion fully before him, and laid out his arrangements with a
perfection that cannot be much improved upon to-day. He
saw clearly what was necessary, and this may be summed up
in the words, Atomizing, Air and Temperature. Hence the
success he attained, and the correctness of his arrangements
and conclusions.
In Fig. 43 are curves showing the consumption of oil and
coal, and in Table XIII are some useful data on specific gravity.
CHAPTER XII
AMERICAN STATIONARY PRACTICE
The Billow System.
fuel oil appliances of the National Supply Company of
. Chicago consist of pumps and atomizers.
Atomizers are actuated in one or a combination of the follow-
ing ways by steam, by air supplied by an air compressor, or
from a positive blast blower or fan.
An oil burner becomes more efficient and approaches nearer
to perfection which will pulverize the greatest amount of oil
with the least energy, and will vaporize oil at the point of
expansion of the agent used for that purpose.
Atomizers are constructed with various shaped openings
annular, flaring, slotted, semicircular or fan-shaped, producing
either a long, round, or a broad spreading flame.
Annular openings are said to be more economical in steam or
air than other forms, as a more intimate association of the oil
and the vaporizing agent is afforded.
By actual experiment atomizers consume from 3 to 15 per
cent, of the entire product of the boiler in vaporizing sufficient
oil to develop the capacity of the boiler.
The number of atomizers required for each boiler or furnace
is directly proportionate to its size. Of atomizing agents steam
is considered the best for boilers, air from a positive blast
blower for furnaces where heat of medium intensity is required,
and air from a compressor for small furnaces. These are
opinions not held universally as regards boiler furnaces.
The Billow Atomizer (Fig. 44) is designed to vaporize the
greatest amount of oil with the least expenditure of energy,
is automatic in its operation within a 5 per cent, steam variation.
It is of a form which it is claimed precludes the possibility of
choking, clogging, dripping or the wasteful use of steam, air or
oil. It is self contained. The fuel and the atomizing agent
are controlled within the burner. It has ground joint union
pipe connexions placed on an axis transverse to the body, a
195
196
LIQUID FUEL AND ITS APPARATUS
feature which permits the flame to be directed as desired. It
has a wide range in adjustment, and will vaporize a few drops
of oil per minute or many gallons per hour. It is constructed
with various shaped nozzles or outlets of the retort type,
when desired, but these are not recommended on account of
their wasteful steam or air consumption. Only in special
Scale
Fig. 44. ATOMIZER. BILLOW SYSTEM.
instances should atomizers other than those with annular
openings be employed.
Fuel Oil Pumping Systems.
In America oil is pumped to the atomizer, not gravitated.
The system for oil handling and control between the storage
AMERICAN STATIONARY PRACTICE 197
tank and the atomizers is an important factor. This system
is designed to -heat the oil, free it from mechanical impurities,
and deliver it to the atomizer at a constant pressure and
temperature under the control of the operator. The amount of
oil necessary for feeding the atomizers should be automatically
controlled, and the system sufficiently flexible to pump the
oil to one atomizer or any number within its capacity without
useless expenditure. It should handle all grades of oil fuel
equally well.
Residuum, or manufactured fuel oil, often contains particles
of coke and sand. All grades may have dirt and other matter
which disturb the adjustment of the atomizers at the furnace
door, necessitating their frequent cleansing. These impurities
clog the feed lines, necessitating frequent blowing-out. An
oil pumping system provides against this by filtering out these
accumulations and cleaning the filtering medium without
disturbing the continued performance of the pump.
Feeding the oil at a temperature nearly approaching the
point of distillation ensures speedy vaporization, with a result-
ant flame soft and diffusing, and not sharply impinging upon
the boiler surfaces. The pumping "system is designed to
give the desired heat, and is provided with automatic govern-
ing valves to ensure uniform delivery.
The National Supply Co. have designed oil fuel pumping
systems for modern fuel oil non-gravity equipments. They
are compact, and so dripped and drained that no oil can reach
the floor.
Any oil fuel produces the best results when heated to a tem-
perature just under its distilling point, and oil is atomized
with less energy when heated to such a temperature and
delivered under constant pressure.
When air is used as an atomizing agent, carbonization is not
liable to occur at the outlet of the burner in the furnace because
the oil is passed through water heated with exhaust steam in
the receiver, and minute quantities of water vapour are carried
over with the oil and prevent carbonizing.
Double Pumping System.
These oil pumping systems (Fig. 45) consist generally of two
duplex steam pumps, specially brass fitted for oil, and of a
cast-iron receiver, tested to two hundred pounds pressure,
mounted on a cast-iron drip pan and base frame upon which the
mechanism is fastened. A partition divides the receiver into
two chambers. Projecting into the rear chamber and screwed
198 LIQUID FUEL AND ITS APPARATUS
to the partition are tubes with fine gauze heads, accessible
through the rear head of the receiver. These heads act as a
straining medium, and there is a blow-off pipe and valve for
removing deposit.
Fig. 45. DOUBLE PUMPING SYSTEM. CAPACITY, 1 to 5,000 BOILER H.P.
The forward chamber is usually two-thirds full of water,
and contains a coil of pipe through which flows live steam or
exhaust steam from the pump. The coil has controlling valves,
permitting the use of steam from either of these sources or both
at the same time.
AMERICAN STATIONARY PRACTICE
199
One pump is in reserve against contingencies or accident to
the other.
The apparatus is provided with a pump governor, or regu-
lator, actuated by the pressure in the receiver to maintain a
constant pressure on the oil in the receiver ; an adjustable relief
valve placed between the suction and the delivery side of the
pump through which all oil in excess of the requirements of the
Fig. 46. COMPOUND TUYERE FOR AIR ADMISSION.
atomizer may pass in case of accident to the governor ; a
thermometer, steam, oil, pressure, and automatically closing
sight gauge.
The oil is discharged through the force chamber of the pump
into the forward chamber. The oil flowing through the hot
water becomes heated and passes out through an inner tube
to the point of consumption.
These pumping systems are made up to sizes of ten to
eighteen thousand boiler horse-power.
200 LIQUID FUEL AND ITS APPARATUS
Thus No. 5 Double, employing two 5j-in. by 3J-in. by 5-in.
duplex steam pumps, has a capacity of five to fifteen thousand
boiler horse-power, or twenty to forty gallons per minute.
In attaching fuel oil atomizers to furnace or boiler fronts it
is sometimes necessary to admit all the air for vaporization
and combustion at
the atomizer, for the
reason that at no
other point can a
sufficient amount of
air be induced into
the furnace to com-
plete combust ion,
owing to conditions of
draught or construc-
tion. The device of
Fig. 46 answers this
purpose, by providing
the air for combustion
irrespective of the
atomizing agent used.
This air for combus-
tion is intimately
mixed with the oil at
the point of admission
into the furnace. It
is intended for boilers
where oil is burned
as an auxiliary to
some other form of
fuel, making it im-
possible to dispense
with the grate bars,
and is therefore use-
ful in connexion with
the burning of
bagasse, sawdust and
material of like char-
acter. It is also the
form used aboard
vessels that employ
water tube boilers.
The tuyere or air regulator attached is shown enlarged in
Fig. 47, the outer part being revolvable so as to close the air slots
and regulate the air admitted round the atomizer. These
Fig. 47. AIR REGULATOR, ATOMIZER AND
TUYERE BLOCK FOR FURNACE FRONT.
AMERICAN STATIONARY PRACTICE
201
appliances are the designs of the National Supply Co., of
Chicago, as also is the arrangement, Fig. 49, of atomizer
tuyere, casting, and internal block of fire-brick which is
intended to be placed in a furnace wall or in the fire- front of
a boiler. The fire-brick has a trumpet-shaped hole through
it, and the nozzle of the atomizer enters a short distance
only, so that the initial flame is contained within the body
of the block. This block has a good effect in effecting perfect
combustion.
An example of the National Co.'s system is the fuel oilplant
of the Union Loop, Chicago, Illinois. This plant consists of a
system for the unloading, storing, circulating, controlling
and firing of fuel oil, after designs prepared by C. 0. and E. E.
Billow.
(J
i
i
;
Fig. 48. SPECIAL TANK CAB S-INCH HOSE CONNEXION.
The plant includes three steel storage tanks, 16, 10, and 8
feet in diameter, and 20 feet high, of a combined capacity
of 1,764 bbls., of 42 U.S. gallons each (35 imp. gals.).
Fuel oil is received in tank wagons, and transferred to the
tanks by two duplex pumps, having 6-in. steam and 7|-in. oil
cylinders, and a 6-in. stroke. These pumps have 6-in. suction
and 5-in. discharge.
Provision is made for unloading four 30 bbl. tank wagons
simultaneously. These tank wagons are attached to oil
hydrants, by steel band lined oil unloading hose.
The storage tanks are provided with flanges for pipe con-
nexions, a 16-in. screw top manhole and cover on the roof, and
an 18-in. on the side near the bottom of the tank, floats and
level indicators by finger boards in the tank room and mercury
columns in the basement.
From the storage, the oil is conveyed to two 4-in. stand pipes,
70 ft. in height, joined by a header near the top, by means of a
202 LIQUID FUEL AND ITS APPARATUS
duplex pump, having 3|-in. steam cylinder, 4f-in. oil cylinder,
and a 5-in. stroke. This pump has a 3-in. suction and a 21-
inch discharge.
From the stand pipe header the oil is conveyed to the oil
atomizer loop, by two No. 5 oil heating and circulating systems,
set upon the boiler room floor. These automatically maintain
a uniform pressure and temperature, and a constant flow of oil.
They consist of a battery of duplex pumps with 5j-in. packed
pistons having 3|-in. oil cylinders, a 5-in. stroke, a 2|-in.
suction and a 2-in. discharge. Each pump has a copper air
Fig. 49.
chamber and is mounted on a cast-iron base and drip pan, to
dispose of all leakage of glands. The base is attached to a
cast-iron frame, supporting one combined steel receiver, heater
and condenser, 24 inches in diameter, and 36 inches high, sur-
mounted by the 7-in. copper air chamber 24 inches high. The
receiver has two diaphragms riveted to its shell, and expanded
full of tubes (125 1-in. boiler tubes, having their ends caulked
and beaded), around which passes the exhaust from the pumps.
The receiver also has provision for the introduction of water,
through which the fuel oil flows, under a high pressure, for the
purpose of breaking it up, in order that all foreign substances
may be precipitated ; the oil passing through the heated tubes
is thoroughly cleansed, and deposits water and settlings.
AMERICAN STATIONARY PRACTICE 203
The drips from the pumps receiver, drip pans, and exhaust
have catch basin connexions.
The whole system is as nearly automatic in its action as is
desirable, and is duplicate throughout.
Each system is capable of delivering sufficient fuel oil to
develop 15,000 horse-power, and occupies a floor space of 30
sq. ft., and is 8 ft. in height.
Four atomizers are placed in the combustion chamber of
each boiler, or a total of sixty-four oil burners compose the
installation. These oil burners receive their oil from a loop,
beneath the boiler room floor, which is divided by valves into
five distinct headers.
The furnaces are erected upon the grate bars of an Acme
stoker, and consist of a series of fire-brick flues for heating
and circulating the incoming air, chequer work for distributing
flame, and baffle walls for directing same.
Oil at the same uniform pressure and temperature can be
delivered to a single burner or to the entire sixty-four.
Furnace Construction.
" Too often it happens that complete combustion is impaired
not from the lack of air, but on account of the method of its
introduction into the furnace, often from such points as to
render it ineffective, producing losses as great as 50 per cent.
For economic reasons no more air should be supplied than is
necessary.
"During the early stages of combustion of any fuel the gases
of a highly volatile nature distil at a low temperature, rise
rapidly, hug the boiler, enter the tubes or flues and pass away
unconsumed. The combustion chamber should therefore be
arranged with fire-brick, so that the incoming air may be heated
to the required temperature, the flames retarded, diffused,
and distributed, and the velocity impeded. There will be no
concentration or localization, and the danger of blistering or
burning is avoided.
"The furnace construction varies according to the type of
boiler or furnace. The question may be asked, * Will an
apparatus work if no change is made in the combustion chamber
or furnace of a boiler other than that of covering the grate
bars ? ' A furnace so arranged will not average so high
economical results as when constructed for diffusing the heat
and retarding the flow of the gases. Fuel oil appliances can
only vaporize the oil ; in the furnace it is consumed. There-
fore the statement is not unreasonable that a scientifically
204 LIQUID FUEL AND ITS APPARATUS
arranged combustion chamber with a shovel to feed the oil is
preferable to a poorly constructed furnace to which is attached
the highest type of atomizing device.
Operating a Fuel Oil Plant.
" The results to be secured from a properly designed fuel oil
plant depend largely upon the amount of intelligence exercised
in its manipulation. All the mechanism that can be supplied,
outside of the furnace, is designed to perform the single function
of delivering the oil to the furnace in a finely divided, nebulized
condition with as little cost to the operator as possible, and to
give insurance against accidents or possible shut-downs, with
ease and facility in manipulation. Other economical results
depend wholly upon the draught. This should be regulated by
the ash-pit doors, or other proper means. The flame may be
increased or diminished at will by the simple opening or closing
of a valve, but it is only by experiment or long-continued con-
tact with fuel oil that the oil, the atomizing agent, and the air
necessary for combustion will be properly combined and the
beneficial results of this combination be obtained. The operator
should continue the opening and closing of the ash-pit doors,
or the manipulation of the damper and the increasing or
diminishing of the flame until he can produce a fire large or
small, without the least indication of smoke. When this con-
dition is attained he will have no more occasion for handling any
of the apparatus provided the elements of combustion are
perfectly balanced.
" The gases should not pass from the furnace at two high a
temperature. This can be controlled and regulated largely
by the damper. A clear flame consumes less oil than a smoky
flame, and has greater efficiency. Smoke is evidence of imper-
fect combustion, but the absence of smoke does not necessarily
prove that perfect combustion is being attained. Too much
steam produces a light grey vapour ; too little, a smoky flame ;
too great a draught, an intensely vibrating flame accompanied
with a roaring noise ; too little draught produces a dull red
smoky flame. When the elements are properly united the
result is a reddish orange flame.
" The temperature of the escaping gases from a boiler will
increase as the excess of air becomes greater, provided the same
amount of fuel is being burned. This is because the furnace
temperature is less, owing to the greater amount of air present
which results in a less rapid transfer of the heat to the boiler
and consequently allows more heat to escape to the chimney.
206
206 LIQUID FUEL AND ITS APPARATUS
" On the other hand, with a uniform excess of air, if more fuel
is burned, the temperature of the escaping gases will increase,
owing to the heat produced being greater in proportion to the
absorbing capacity of the boiler."
It is only through close application that the theory of oil
burning can be fully understood and mastered and as high an
efficiency as 80 per cent, of the theoretical value of the fuel
transmitted from the furnace to the boiler. Mr. C. 0. Billow
has designed furnaces for many types of boilers. Fig. 50 is the
ordinary American under-fired tubular boiler with the bars
replaced by a fire-brick air casing, through which air flows to
Fig. 51. WATER-TUBE BOILER. BILLOW SYSTEM.
the furnace through the " ash-pit " door and comes up under
the atomized jet. The furnace widens out laterally from
front to rear, the atomizer being placed at the narrow end of
this brick furnace. The grate bars are ten inches lower than
usual, and the air casing of brick occupies this ten-inch space.
The ash-pit doors regulate the air admission. The atomized
oil is directed upon the chequer work brick bridge, which
breaks up and diffuses the flame throughout the furnace and
directs it upon the boiler. A hanging bridge is placed at the
extreme end of the combustion chamber. If too little air has
been admitted at the front, a further supply is let in through
this rear bridge, which also serves further to retard the flow
AMERICAN STATIONARY PRACTICE
207
of the hot gases. Either steam or air may be used as the
atomizing agent, and though air is the more efficient, the cost
of the air compressor detracts from its advantage, but a good
compressor saves steam. Mr. Billow considers that steam
atomizing should be done with 3-3 per cent, of the total steam ;
that a positive air blast blower will only use 1-36 per cent, of the
boiler output, but when air is compressed above 30 pounds
absolute, it costs 6 per cent, with ordinary compressors. Hence
the importance of good compressors. The same system is
carried out in the ordinary water- tube boiler (Fig. 51). This
furnace is applicable to the many forms of water-tube boiler.
The same grate cover of fire-brick is employed, but the bars
," OIL PIPE
NAVY GLOBE VALVE
2 ' AIR PIPE
TYPICAL MOUNTING
or
CLASS "LM" BILLOW ATOMIZER 9"
Fig. 5 la.
are lowered considerably to provide room for the concave
bridge, which is also split to admit air. The burner points
somewhat down so as to strike on the brick floor at about half
length, the flames curving round the bridge hollow.
It may be added that for English practice the containers
of oil pumping systems, if employed in preference to gravity
feeds, of Fig. 45 type should be of boiler plate and not of cast-
iron a material, the use of which for pressure work, and
especially for pressure work with liquid fuel, is considered
indefensible, and would probably not be passed as safe by
the English boiler insurance companies. Fig. 5 la shows a
typical boiler mounting on the Billow system.
CHAPTER XIII
ENGLISH STATIONARY PRACTICE WITH LIQUID FUBL
The Kermode System.
IN this system air at low pressure is the atomizing agent,
the air being heated in a thick retort pipe, which is
carried round the furnace or uptake.
Oil gravitates from an overhead tank, as very usual in
marine work. It flows thence by a IJ-in. pipe to the furnace
front and separates to the two burners by equal branching
pipes. Where two burners are supplied off one pipe the
branches to each must be symmetrically arranged in order
that equal supplies of oil may reach each burner.
The illustrations represent one form of the furnace arranged
by the Wallsend Slipway Co. for this system, the lower
part of the marine furnace being filled with special fire-brick
blocks through which air enters the furnace beneath the flame.
These blocks are covered with asbestos lumps similar to the
ordinary grate of Fig. 53, which shows an alternative arrange-
ment including also an oil heating pipe in the furnace in addition
to the air heating pipe.
The accompanying table of tests and copy of analysis of
Borneo oil are given from results of trials at the Wallsend
Company's Works
COPY OF ANALYSIS BY DR. GEORGE TATE, F.I.C,, F.G.S.,
NOVEMBER 9, 1899.
Sample.
Astatki.
Borneo
Crude Oil
as received.
Borneo
Crude Oil
dried.
Water
p. c.
trace
p. c.
11-75
p. c.
Carbon
79-92
73-60
83-40
Hydrogen
12-00
9-08
10-29
Oxygen and undetermined elements
8-08
5-57
6-31
Total
100-00
100-000
100-00
Calorific power in B.Th.U. .
18434
15-894
18-010
Equivalent evaporative power
19-0 Ib.
16-41b.
18-6lb.
208
209
s
210
ENGLISH STATIONARY PRACTICE
211
LiquiJFuat
Pipe
Oil
An
Fig. 53. LIQUID FUEL FURNACE. KERMODE'S SYSTEM. ALTERNATIVE
ARRANGEMENT.
Date of Trial.
Sept. 6,
1899.
Sept. 14,
1899.
Sept 19, 1899.
Duration of trial
3 hours
4 hours
2 hours
Class of oil used
Borneo
Borneo
Borneo crude
crude
crude
First hour
Second hour
Mean pressure on boiler, Ib.
111
110-5
109-8
110-4
Total Ib. of water evaporated .
24,161
35,323
9362-5
9511
Pounds evaporated per hour
8053-7
8830-75
9362-5
9511
Pounds of water per pound of oil
11-1
10-9
10-93
10-92
Ditto from and at 212F. .
12-9
12-75
12-85
12-84
Mean temperature of feed water
deg. Fahr
89
89
83
83
Temperature of oil in measuring
tank, deg. Fah
68
68
67
67
Total gallons of oil consumed .
225-3
337
88-8
90-2
,, pounds of oil consumed .
2174
3244
856-5
870-3
Gallons consumed in 1 hour
75-1
84-2
88-8
90-2
Pounds consumed in 1 hour
724-7
811
856-5
870-3
Pressure on oil at burner pound .
4-3
4-3
4-3
4-3
Specific gravity of oil ...
965
965
965
965
Temperature of uptake deg. F. .
650
665
720 ! 720
Smoke at funnel top.
Light
Light
Light brown
brown
brown
Air pressure in burner, pounds
3-2
3-2
3
Revolutions of blowing engine .
310
350
320
Pounds of oil per sq. ft. of grate
18-1
20-3
21-5
Pounds of water per sq. ft. of
heating surface ....
4-75
5-5
5-5
7 -5 per cent, of water in the oil is allowed for in the above results.
This seems rather excessive, but probably explains the results.
212 LIQUID FUEL AND ITS APPARATUS
The boiler had the following dimensions :
Mean diameter 12 ft. 6 ins.
Mean length lift.
Two furnaces 3 ft. 7 ins. inside diameter.
262 tubes 2 ins. external diameter,
8 feet between tube plates
Heating surface of tubes .... 1,372 sq. ft.
Furnaces 123
Combustion chambers 125
Tube plates 75
Total 1,695
Grate area of one surface. ... 20
Diameter of chimney 5 ft.
Height from bars 55
The burners are arranged so as to be readily swung back
when coal firing is to be resumed, and there is very little change
to the furnace in the system of Fig. 53. Probably the light
smoke which is made might be reduced by the use of somewhat
more fire-brick in the furnace or combustion chamber.
Tests made at Birkenhead are said to have shown an evapora-
tion as high as 15-5 pounds from and at 212F. per pound of
Russian astatki and without smoke. Borneo oil is credited by
Dr. Tate with less hydrogen than usually is found in petroleum
fuels, the average formula apparently being C 7 H ]0 . The latest
burner for this system is described under the head of atomizers,
Fig. 68.
The remarkable thing in this system is the satisfactory results
obtained with only 3 pounds of air pressure, but it must be noted
that this air is highly heated. The above trials, made many
years ago, show what improvements have since been made for
to-day (1911).
The following figures show the results which can be obtained
on a steam boiler fitted with any one of the three systems
of atomization used in the Kermode system.
Oil fuel, which has a theoretical calorific value of 19,320
British thermal units per pound, is capable of evaporating 20
Ib. of water from and at 212 F. (theoretically) for every pound
of oil consumed, and if the air-jet system is used, from 15-6
to 16-6 Ib. of water can be evaporated per pound of oil consumed
under practical working conditions. That is to say, from 78
per cent, to 83 per cent, of the theoretical calorific value of the
oil is recovered for useful work.
The pressure-jet system will recover from 70 per cent, to 75
per cent, of the theoretical calorific value of the oil fuel used in
actual practice. That is to say, with oil fuel of 19,320 B.Th.U.'s
213
214 LIQUID FUEL AND ITS APPARATUS
per lb., the evaporation per pound of oil consumed would be
from 14 to 15 lb. of water per lb. of oil consumed.
The steam-jet system will recover from 68 per cent, to 74
per cent, of the calorific value of the fuel used, or a pound of
oil foul will evaporate from 13-6 to 14 8 lb. of water.
For dealing with the by-product (tar) from the Mond Gas
power plant, the Kermode system converts a hitherto useless
refuse to liquid fuel, and by this means an enormous saving is
effected in the fuel bill of Mond Gas plants.
The Kermode system embraces all three methods of atomiza-
tion by air, by steam and by oil pressure, without other agency,
the oil spraying itself by its own energy. An example of each
type of sprayer will be found in the chapter on atomization.
In Fig. 54 is shown a recent Kermode furnace as arranged
under a Babcock boiler, on a test of which 13-32 lb. of water is
stated to have been evaporated at 1 00 lb. pressure from feed at
64-4F. per lb. of oil, the efficiency being 79-65 per cent.
The burners themselves are shown at A, the air pipes at B,
the oil-pipes at C, the oil-main at D and E, the air-mains at
G, from which the branch-pipes A go to the burners, and the
air-compressor at M, from which the air passes along the pipe
to the heater K. An air by-pass valve is shown at N, and air-
pipes 0, 0, which lead to the flue and discharge the surplus air
when required. The results have quite come up to expectation,
for the evaporation from and at 212F. has proved to be
15-91 lb. of water per pound of fuel, although the oil was not of
a very high calorific value.
During test mentioned the water evaporated per hour was
at the rate of 1362-5 kilogrammes (3,004 lb.) per hour. The
pressure of the air supplied to the burners was 0-7 lb. per
square inch, with very slight variations. The temperature
of the feed- water was 64 4F., and that of the liquid fuel
69-8F. The amount of oil consumed during the eight hours'
test was 1,801 lb., and the total amount of water evaporated
was 23,980 lb. The Kermode system is applied equally to
land or marine work, and to fire engines and small work, and
any liquid fuel is utilized, notably the tar of the Mond Gas
producer.
Numerous large and small vessels of the Navy have been
fitted with this system.
The Hydroleum System.
In this system great stress is laid upon the spraying of the
oil through a comparatively restricted area or passage upon a
ENGLISH STATIONARY PRACTICE 215
Fig. 55. WATER TUBE BOILER WITH HYDROLEUM LIQUID FUEL SYSTEM.
dash-brick, which, it is claimed, becomes highly heated and
vaporizes the spray. This is shown in Fig. 55.
Tested with water gas tar at the works of Messrs. Muirhead &
Co., Elmer's End, Kent, the following results were obtained :
Oil. Coke.
Date Aug. 14, 1901. May 15, 1901.
Duration of test 2 hours 9 hours
Mean temperature of feed water. . 70 Fahr. 60 Fahr.
Mean pressure on boiler . . . 90 Ib. 90 Ib.
Pounds of water evaporated . . . 2,400 10,100
consumed ... 211 1,792
Pounds of water evaporated per Ib.
from and at 212F 13-47 6-73
Price of tar 19s. Q$d. per ton = 402d. per Ib.
Price of coke 21s. Sd. per ton = -116d. per Ib.
N.B. In making the test the tar was taken as received, no
deduction being made for any water it contained.
Comparing these two tests it will be seen that :
To evaporate each pound of water with coke cost . 0-0172df.
To evaporate each pound of water with water gas tar 0-0075d.
Saving by the system of oil firing 0-0097d. per Ib.
216 LIQUID FUEL AND ITS APPARATUS
The burner of this system will be found described under the
head of atomizers, but the Hydroleum Company do not profess
to atomize. They lay stress upon the use of a dash-brick only
about 18 inches in front of the spray nozzle, an intense local
heat being developed on the face of the brick. Sufficient air
to burn the vaporized oil is induced through the openings
provided round the spray nozzle. The sprayer is made in three
sizes, having capacities of 1, 3, and 10 to 12 gallons of oil per
hour, and the oil is induced to flow by the inductive action of
the steam annulus. The feed tank is kept at a level of half an
Fig. 56. HYDBOLEUM LIQUID FUEL SYSTEM. MAHINE BOILEK DESIGN.
inch below the nozzle by means of a ball float valve. From
14*5 to 15 pounds of water are stated to be evaporated from and
at 212F- per pound of oil, the expense of steam being 5 per
cent, of the evaporation.
Though not claimed as an atomizing system, the Author
considers that the effects of the Hydroleum burner sufficiently
resemble atomizing for this burner to be held up as an example
of the success of the system.
Experience shows that for a burner capable of burning 10
ENGLISH STATIONARY PRACTICE 217
gallons per hour there should be an opening for air round the
atomizer of 8" x 8", which, after deducting the cross section
of the atomizer itself leaves sixty square inches of air opening
for ten gallons per hour. Worked out on the basis of 15 Ib. of
air per Ib. of oil fuel and 13 cubic feet per Ib. the velocity per
second of the air stream is only 13 feet. A gallon of fuel is
taken as 10 Ib., which is about correct for tar. The amount
of fuel fed is simply regulated by the amount of steam used,
and this draws in more or less air as required by the fuel, and
very little regulation of the air inlets is required. A trunk
casing is placed round each burner with opening downwards to
reduce noise. This gives very effectual silencing. These air
trunks may be all coupled to a common air main brought from
outside the building. As seen by the Author, burning oil gas
tar of Sp. Gr. 1-04 in a Lancashire boiler the system was smoke-
less and very silent. The Hydroleum atomizer will be found
described in the chapter on atomizers.
CHAPTER XIV
THE COMBUSTION OF VAPORIZED LIQUIDS
The Clarkson and Capel Burner.
IN this burner system the liquid employed is preferably the
cheaper and commoner qualities of lamp oil. The
burner shown (Fig. 57) is one that is fitted to floating fire
engines. It is capable of burning 40 gallons of oil per hour
and of developing up to 200 h.p.
There is a gas ring to give the initial heat to vaporize the oil.
The jets heat the coils to which the oil is fed, and the vapour
passes from the coil to the rear of the long casting, which it
enters through a small orifice controlled by a needle point.
Air is admitted by a door at the back end and the vapour and
air are thoroughly mixed in the pipe and issue round the lip
of the mushroom valve, where ignition takes place and a large
flaring flame of great intensity, is formed, the heat from which
now vaporizes the oil in the coil, and the process is continuous.
The oil is under pressure in the supply tank, the pressure being
generated by an air pump. The pressure forces the oil through
the system, and when, in vaporized form, this reaches the jet
nozzle, it issues with a high velocity and induces a large flow
of air through the valve. The needle of the jet nozzle is worked
by the same controlling lever as regulates the cap of the burner.
In the course of this lever, which is of compound order, is a
maximum and minimum stop that can be regulated to prevent
excessive opening or entire extinguishing of the flame. The
hand wheel of the larger burner in Fig. 57 shows how this is
effected.
In the automobile pattern (Fig. 58) the initial heating device
is a spirit trough containing a coil of nickel wire. Petrol or
alcohol can be employed. The burner is placed in the cylindrical
base of the boiler ; the case bottom is perforated for air admis-
sion and provided with a door for inspection.
A system of preliminary heating by means of paraffin con-
sists of a series of asbestos wicks provided with an air
218
219
220 LIQUID FUEL AND ITS APPARATUS
draught by a small fan and fed with a limited quantity of
paraffin from a small cup, the main supply of oil being heated
in the f-inch coil.
After the cupful of
paraffin is finished the
flame of the main
burner will be burning
and will provide heat
for further vaporiza-
tion.
For use in automo-
biles, small steam-boats,
the cheap forms of
lamp oil are commerci-
ally practicable, though
they would be too ex-
pensive for ordinary
continuous industrial
steam raising purposes.
For other reasons these
oils commend them-
selves for the purposes
of fire engines and fire
floats. Here the use of
expensive fuel is war-
ranted by the nature of
the service, namely, the
extinguishment of a fire
that may be consuming
valuable buildings and
their contents. Even
the lighter petrols are
used for steam raising
purposes in certain
forms of steam cars,
) Inf the petrol being sprayed
upon a hot cast iron
plate through which fine
jets of air are intro-
duced and the heat is
utilized to raise steam
in coil boilers of the
flash type into which water is injected to provide the steam
for instant use.
In the Clarkson system one pound of oil can be counted
THE COMBUSTION OF VAPORIZED LIQUIDS 221
upon to give an evaporation of 10 pounds of water from 80C.,
to steam at 200 pounds, or an equivalent evaporation from 212
F. of nearly 11 pounds. The oil receptacle is usually worked
at a pressure of 40 pounds, and the cheaper grades of Russian
oil are perhaps the most suitable, such as Rocklight, Lustre, etc.
As stated elsewhere, the calorific capacity of all the petroleum
products is practically identical, the lighter oils being more
powerful because they contain the highest percentage of hydro-
gen, but the difference is immaterial. The evaporative effici-
ency of the small boilers of cars and canoes, is less than that of
large boilers simply because it is not desirable to load up a car
with too great a weight of heating surface.
In the starting device employed on automobile cars, a pad
fed with a drop feed of oil is ignited by a match and gives pre-
liminary heat to the burner.
The combustion of petrol is a special case of vaporization
before combustion. Petrol has such a low flash point that it
is absorbed by air passing over it, with great avidity.
Petrol engines are simply gas engines with electric ignition
which use petrolized air. The petrol is fed into a vessel called
the carburettor in small quantities by the action of a float, and
it is taken up by a stream of air which is drawn through the
vessel by the pistons of the engine. The petrol is used as
supplied. Petrol being a mixture of different hydrocarbons
with each its own flash point, no system of petrolizing of air
can be satisfactory where the air is drawn over a mass of petrol,
for the air will select first the lighter constituents and leave
the heavier behind. In all cases the petrol must be put within
reach of the air in small quantities at once, so that the whole
portion added is carried off by the stream of air before more is
added. The evaporation by the air produces a chilling effect
and raises the flash point of the liquid. Carburettors must
therefore be warmed by a hot water jacket or by the exhaust
gases of the engine.
The lamp oil qualities of paraffin may be atomized by air
into the space below a perforated disc of metal forming the
cover of a shallow drum. The vaporized paraffin issues from
the slits of the burner plate and burns with a blue Bunsen
flame and this burner is used for small boilers of the flash type.
The flame keeps the burner plate hot enough to vaporize the
paraffin in the space below. An initial heater is necessary for
starting the burner.
CHAPTER XV
COMPARISON OF AIR AND STEAM ATOMIZATION
The Ellis and Eaves System.
IN this system, the atomizing is done by steam, and heated
air is supplied to the furnaces, the draught being fan
induced. The air is heated in tubular heaters having two-
thirds of the boiler heating surface, and placed over the boiler
in the course of the gases to the fan, as shown in Fig. 59 ; the
admission of air to the furnaces being, as in Fig. 60, round the
outside of the atomizer.
Tests were also made with air as the atomizing agent.
The air pressure was 20 pounds per square inch, and the results
are given below. A subsequent test with air at 35 pounds
pressure showed 11,108 pounds of water per hour from and at
212F. per pound of coal and 15-49 pounds per pound of oil. This
is somewhat less than with air at the more moderate pressure of
20 pounds. The atomizing air had a temperature of 80F.
only, or it might have given better results.
The difference between steam and air atomizing seems to be
practically nil. For land work it remains simply to compare
the amount of steam used direct with that used in compressing
the air.
The analysis of the flue gases showed a mean result of 11-2
per cent, of C0 2 and 10 per cent, of oxygen in the left hand
furnace and 14-1 per cent, of C0 2 and 8-4 of oxygen in the
right hand furnace, the mean of both being C0 2 = 12-6,
0=9-6, C0=0.
The tests made with this system of induced draught and oil
fuel burning, of six hours' duration, were a success, but the
question was raised whether the system could be worked for a
lengthened period without giving trouble through deposits of
soot and unconsumed oil becoming ignited in the air heater and
casings, and a continuous test of 120 hours was made, careful
observations being taken of the temperatures, evaporations, etc.
AIR AND STEAM ATOMIZATION
223
Particulars of boiler, wli3li were the same as in the previous
tests
12 ft. mean diameter by 11 ft. mean length, fitted with two
Purves furnaces of 3 ft. 9 in. inside diameter.
Fig. 59. ELLIS AND EAVES SYSTEM, MARINE BOILER ARRANGEMENT, FOR
HEATING AIR.
148 Serve tubes, 3| in. outside diameter by 7 ft. 9 in. long
and retarders.
Heating surface, 1,200 sq. ft. Grate surface (for coal burn-
ing) 43 sq. feet.
POSIT/OH or On Buaticitf
Valves open for -ft
all tests
Fig. 60. ELLIS AND EAVES SYSTEM, FURNACE DOOR ARRANGEMENT.
Ratio of H.S. to G.S. 28 to 1.
Fitted with the Ellis and Eaves system of induced draught.
Surface in air heating tubes, 800 sq. ft.
Diameter of Fan wheel, 7 ft. 6 in.
224 LIQUID FUEL AND ITS APPARATUS
The boiler feed supply was taken from two tanks, each of
800 gallons and two oil supply tanks for burners, having a
capacity of about 900 gallons each were provided. The oil
was fed to burners at 75F.
Steam to the burners was supplied at 70 pounds per square
inch. Texas oil was used, closed flash point 185, calorific
value 18400 B.Th.U. Sp. gr. '0-915.
Smoke was visible for a few seconds when changing over the
oil tanks about every eight hours. Heated air was provided ;
the difference in right and left hand temperatures of air entering
the fires being due to the fact that the right hand air heating
box and air casings are protected from the weather by a wall,
and also that the air entering these is at a higher temperature,
due to radiation from the fan discharge.
The test was started on Monday, December 15, 1902, at
eleven a.m., the boiler being cleaned before starting, and was
continued night and day till eleven a.m. on Saturday, December
20, the installation working without a hitch during the whole
of that time. Burners required cleaning occasionally, but
this was carried out one at a time, and only occupied a few
minutes. Hot air was admitted to the furnaces, the greater
portion of this only being admitted round about the burners
through vena-contracta nozzles.
At the end of the trial the boiler, air heater casings, etc.,
were opened up and examined by representatives of the Wall-
send Slipway Co. and the International Mercantile Marine Co.,
and found to be perfectly clean and in good order, there being
no indication of flaming in the casings. From the foregoing
and a perusal of the following tables, the perfect combustion
of the oil may be attributed to the use of heated air ; no smoke
is formed and there is no deposit of inflammable oil or soot on
the tubes or casings to take fire.
From the table on page 227 the advantages of air heating are
shown up clearly. Air which enters the heater at about 54 F.
leaves it at about 284F., having taken up 230 of temper-
ature, all of which is absorbed from the furnace gases, which
are reduced from about 760F. to 520F. more or less. They lose
the 230 gained by the air, and this alone represents a very
considerable economy, something like 33 per cent, of the other-
wise waste heat passing up the chimney. The fan efficiency
is also increased. Assuming that the furnace temperature is
2,800F. the heating of the air by the waste gases would appear
to represent an economy of fuel of 8 to 10 per cent., apart
from the higher boiler efficiency 'due to increased temperature
head.
AIR AND STEAM ATOMIZATION
225
Air heating is thus advantageous both in economy and more
perfect combustion.
STEAM ATOMIZATION.
Time.
Steam
Pres-
sure.
Fan
Revo-
lutions
Vac-
uum
at
Fan
Suc-
tion,
Vac-
uum
at
Fur-
nace.
Tem-
per-
ature
of Air
enter-
ing
Heater.
Heated Air
entering Fires.
Escap-
ing
Gases
entering
Air
Heater.
Escap-
ing
Gases
at
Fan
Suction.
Feed
Water
Tem-
per-
ature.
Water
Time
taken to
empty
Tanks.
Oil.
Gals.
Left.
Right.
Tank
Mins.
Tank
2.
Mins.
10-0
145
305
2J*
r
75F.
235F.
300F.
700F.
475F.
60F.
46
10.30
135
309
2r
r
75
235
290
700
475
60
49
82$
11.0
140
308
2J"
r
75
232
285
695
470
55
11.30
135
305
2i"
r
75
230
285
695
470
58
55
80
12.0
12.30
140
300 2*
r
75
227
275
675
455
58
137
299 2J*
r
75
233
275
700
460
58
41
40
81*
100
93|
1.0
140
308
21*
r
75
242
295
715
485
58
39
1.30
130
302
21"
r
75
247
305
710
490
58
2.0
150
305
21*
r
75
248
308
715
490
58
2.30
145
305
21"
r
75
248
305
715
485
58
40
3.0
140
312
21"
r
76
245
295
705
475
58
42
3.30
140
310
21"
r
75
245
290
705
485
58
135 gals,
out of
last tank.
Total
6,535 gals.
82$
4.0
145
309
21"
r
75
246
295
710
505
58
Total
530.
Water evap. per hour.
Actual observed conditions.
10,891
Ib.
Water evap. per Ib. of Oil.
Actual observed conditions.
134
Ib.
Water evap. per hour,
from and at 212 Fah.
13,145
Ib.
Water evap. per Ib. of Oil
from and at 212 Fah.
16-1
Ib.
Water evap. per sq. ft. H.S.
Actual observed conditions
9
Ib.
Water evap. per sq. ft. H.S.
from and at 212 Fah.
10-9
Ib.
Theoretical total heat value
of Oil in Ib. of water from
and at 212 Fah.
19-14
Ib.
Efficiency of Boiler.
84%
The steam tests were of 6 hours' duration, those with air of
four hours'.
p
226 LIQUID FUEL AND ITS APPARATUS
AIR ATOMIZATION.
Time.
Steam
Pres-
sure.
Fan
Revo-
lutions
per
min-
ute.
Vac-
uum
at
Fan
Suc-
tion.
Vac-
uum
at
Fur-
nace.
Tem-
per-
ature
of Air
enter-
ing
Air
Heater.
Heated Air
entering Fires.
Escap-
ing
Gases
entering
Air
Heater.
Escap-
ing
Gases
at
Fan
Suction.
Feed
Water
Tem-
per-
ature.
Water
Time
taken to
empty
Tanks.
Oil.
Gals.
Left.
Right.
Tank
Min's.
52
Tank
2
Mins.
10.30
130
297
21"
ii"
74F.
220F.
225F.
600F.
360F.
50F.
11.0
130
297
21*
ir
74
216
245
630
400
50
47
68-4
99-28
11.30
130
300
21"
ii"
74
225
250
630
410
50
12.0
130
300
21"
H*
74
225
250
630
410
50
45
12.30
130
298
21"
ii"
74
223
250
630
410
50
1.0
140
298
21"
ii"
74
223
250
630
410
50
45
86-04
83-83
1.30
2.0
140
298
21*
ir
74
225
250
630
410
50
140
298
21*
ir
74
225
250
630
410
50
46
2.30
135
298
21*
ir
74
225
250
630
410
50
90 gallons
taken from
last tank.
Total
4,090 gals.
Total
337-55
Water evap. per hour
Actual observed conditions.
10,225
Ib.
Water evap. per Ib. of Oil.
Actual observed conditions.
13-24
Ib.
Water evap per hour,
from and at 212 Fah.
12,413
Ib.
Water evap. per Ib. of Oil
from and at 212 Fah.
16-07
Ib.
Theoretical total heat value
of Oil in Ib. of water from
and at 212 Fah.
19-14
Ib.
Efficiency of Boiler.
84%
AIR AND STEAM ATOMIZATION 227
Z&
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CHAPTER XVI
THE STORAGE AND DISTRIBUTION OF LIQUID FUEL
IN carrying or storing oil, it is necessary to provide for its
expansion, and it is also necessary to provide a safeguard
against the rupture of the storage tanks unless these are below
ground level. Provision must also be made for the escape
of any gas or vapour generated from the oil and against danger
from leakage.
The tanks used for oil storage have a diameter of from 40
to 70 feet. Some are as large as 90 feet, and the largest will
hold over one million gallons, or 3,300 gallons per inch of
depth. To prevent danger, should a tank fail, it ought to
be surrounded by a moat capable of holding the contents of
the tank. Both crude oil and the refined products are now
carried in specially constructed tank steamers, some of which
will carry as much as 8,500 tons of oil.
At Liverpool these steamers are discharged through an
8-inch pipe into vertical tanks of 2,000 and 3,000 tons capacity.
The carrying space in the steamers is formed by riveted bulk-
heads across the ship, the skin of the ship itself forming sides
to the tanks, the screw shaft being laid in a tunnel. Refined
oil possesses such penetrative properties that the riveting of
such tanks must be carefully done, and the rivet spacing is
closer than in ordinary work. The tanks ought to be full of
oil, and they must not be too large, a bulkhead being placed at
intervals not wider than 24 feet. These bulkheads must be
stiff enough to stand the unsupported pressure of the liquid
upon one side only, together with such extra stress as may be
caused by the movement of the vessel. The specific gravity
of petroleum varies considerably, but an approximate rule
to cover all cases of oil pressure is P = 040 H, where P is the
pounds pressure per square inch and H is the depth in feet below
the top level of the oil, which may of course be some distance up
the expansion tanks.
It is not considered safe to store Texas crude oil nearer to
STORAGE AND DISTRIBUTION OF LIQUID FUEL 229
boilers than 500 feet, and in case of a spouting well all fires
within 500 feet are extinguished.
Where oil is used freely as fuel it may be lead to the different
establishments by pipes in preference to carting it in tanks.
The pipes ought to be of wrought iron or steel, carefully thread-
ed and fitted together with sound and carefully threaded
sockets. Pipe joints may be made in three ways : (a) The pipes
are screwed tapering and the sockets ought to be threaded
similarly from each end by a tapering tap, so that a tight joint
may be secured ; (6) Back nuts may be employed to reinforce
the sockets by aid of an interposed fibrous ring ; (c) The pipe
ends may be truly faced off exactly at right angles to the axis
of the threading, a compressible, but thin, washer of soft metal
or fibre being interposed between the ends of the abutting
pipes. Such pipes meet together in the sockets like artesian
drive pipes.
Ordinary pipes, if found to leak after being put together,
should be caulked round the ends of the sockets. Before
screwing together the threads ought to be painted with some
cement not soluble in petroleum. Litharge and glycerine is
recommended. Many of the precautions with regard to oil
arise from the fact thao, being lighter than water, it may be
carried up and down a tidal river and spread a general conflag-
ration. Being liquid, it will travel by gravity to long distances.
Where, to avoid danger, oil is stored in buried vaults, there is
danger of the accumulation of explosive vapours, and ventila-
tion is required ; the outlet of a ventilating shaft should
be well exposed and out of such danger as the throwing of a
lighted match from some point above. Where ventilation
does not take place freely, it might be necessary to use positive
means of drawing out the air from a tank chamber or to assist
the action of the ventilating trunk by a warm water pipe within
it and a swivelling cowl head.
To deal with the liquid fuel locomotives of the Great Eastern
Railway, there were provided a series of underground tanks of a
capacity in the aggregate of 50,000 gallons, filled direct from
the travelling tanks of the railway.
From these underground tanks a Tangye Special pump lifts
the oil to cylindrical tanks 20 feet above rail level, and of a
total capacity of 42,000 gallons.
Outlet pipes controlled by valves, operated from a gallery
above, conduct the oil to cranes similar to an ordinary water
crane.
A main line engine will take in 600 gallons of oil in four or
five minutes.
230 LIQUID FUEL AND ITS APPARATUS
Electric lighting is employed, with portable lamps for the
cranes or filling arms.
Oil may be stored underground only, and in airtight tanks,
which are caused to supply the filling arms by pumping air
into the tanks above the oil, the air brake pump of the locomo-
tive itself doing this work.
The tanks of the tender are filled through a fine gauze strainer,
protected by a perforated cylinder, so that everything in the
shape of an obstruction is filtered out, and the gauze also
serves to prevent ignition of any possible vapour in the tank,
acting to prevent this on the well known principle of the miner's
safety lamp. This precaution is more necessary where crude
oils are used than for the higher flash point residues.
On the Grazi and Tsaritzin Railway Mr. Urquhart, in his
1884 1 paper gave the length of line worked with petroleum as
from Tsaritzin to Burnack, 291 miles, and a total of 423 miles,
including the Volga-Don branch. There is a main reservoir
for petroleum, at each of the four engine sheds, 66 feet diameter
and 24 feet high, and about 2,050 tons capacity. The reservoir
stands a good way from the line and from dwelling houses and
buildings.
On a special siding are placed 10 cistern cars full of oil, the
capacity of each being about 10 tons. From each car a connec-
tion is made by a flexible india-rubber pipe to one of the ten
standpipes, which project one foot above the ground line.
Parallel with the rails is laid a main pipe, with which the ten
standpipes are connected, thus forming one general suction
main. About the middle of the length of the main, which is
laid undergound and covered with sawdust or other non-
conducting material, is a steam pump which in about one hour
discharges the whole of the cars into the main reservoir. The
pipes are all wrought iron, lap welded, 5 inch socketed.
At each shed there is an elevated tank (Fig. 61) 8 J feet dia-
meter by 6 feet deep, built of J in. plate, to serve as a distribut-
ing tank to the locomotives. A divided scale shows exactly
how many poods 2 of oil have been drawn out, the amount
being corrected for temperature at intervals of 8R. = 18F.
10C., the scale ranging from 24R. to - 24R. 86F.
to 22F., the quantity and temperature being entered in the
driver's book. The heaviest refuse has a specific gravity of
0-921 at 0C. = 32F., so that 39 cubic feet measure one ton,
or 57-4 pounds = 1 cubic foot. Lighter refuse has a specific
1 Proceedings of the Institution of Mechanical Engineers, 1884.
2 1 pood = 36-114 English pounds = 40 pounds Russian. 62'0257
poods = 1 ton.
STORAGE AND DISTRIBUTION OF LIQUID FUEL 231
Distributing Tank /.\
.,'
WFett
Fig. 61. DISTRIBUTING TANK FOR OIL FUEL. GRAZI AND TSARITZIN
RAILWAY.
gravity of 0889 = 40 J cubic feet per ton, or 55 J pounds per
cubic foot.
The engineer-in-charge at each station is provided with a
hydrometer and thermometer to deal with the ten different
grades of liquid, each grade having its own peculiar sp. gr. and
co-efficient of expansion. Table XIII gives useful information
on this subject.
Oil Pumps.
Any pump which will pump water will pump oil, if not too
viscid. So long as an oil is free from the more volatile hydro-
carbons, it can be lifted by suction from a depth greater than
is possible with water, in inverse ratio to its specific gravity.
By weight a pump will throw less oil than water, but it should
throw an equal volume.
For rapidly transferring large bodies of oil from a ship to a
storage tank, the centrifugal pump is very convenient. There
232 LIQUID FUEL AND ITS APPARATUS
are also numerous other rotary pumps of the positive propulsion
type similar to the Roots' Blower. But viscid oil can hardly
be moved by a centrifugal pump.
Fig. 62. WEIR'S OIL PUMP.
Valves of india-rubber must of course be avoided, and only
such substances employed as will resist the solvent action of
the oil. Metal valves should prove most generally durable and
efficient. Simplicity and reliability are the characteristics
STORAGE AND DISTRIBUTION OF LIQUID FUEL 233
desired in a pump. For bunker filling especially the pump
must be of ample capacity, so that a ship may not be long
detained when calling for fuel in port.
An example of a bunkering pump is the Weir Patent Pump
for oil pumping as shown in Fig. 62. This is of the direct
double-acting type. The valve gear is positive, i.e. the steam
valve can never be in such a position that the pump will not
start immediately after the steam is turned on. The valve
arrangements also ensure constant length of stroke and cer-
tainty of action.
The steam valve consists of a " D " slide valve with a small
auxiliary valve working on the back. These are the only
moving parts proper in the steam chest, so that there is little
opportunity for wear and no delicate adjustments to get out
of order.
The oil end as shown is fitted with Weir group valves,
which provide a large area with only a small lift, thus ensuring
easy working and little wear and tear. In more recent types
these valves are of the Kinghorn type and the discharge
branches look upward, not outward. In larger sizes the
piston rods are divided, and the two are connected by a screwed
crosshead.
The pump is specially economical in steam consumption,
and is simple and with all its parts easily accessible. The
front elevation shows that there is a separate valve chamber
for each end of the pump cylinder, the valves being grouped
on the valve plate round a central valve. With long pump
buckets there should be no need to use rings. The bucket
simply requires to be turned a good but free fit in its barrel
and grooved with square edged grooves J" wide x TfV" deep,
spaced about | \" centres. This plan is very effectual with water,
and should be perfect for oil of the consistency of fuel oil.
FLUE GAS ANALYSIS.
The analysis of flue gases is undertaken for the purpose of
showing the perfection of the combustion and the excess of air
employed.
Considering that about 9 per cent, more coal is consumed if
the percentage of C0 2 is 8 per cent, instead of 13 per cent., the
waste of coal will amount to 900 tons a year in 10,000 tons
burned. Oil stands on the same level.
In practice, about 1 -3 times the theoretical quantity of air is
required to effect perfect combustion.
How much coal is wasted, if the percentage of carbonic acid
234 LIQUID FUEL AND ITS APPARATUS
gas falls to a low level, may be seen at a glance from the follow
ing table
Percentage of
C0 2 . . .
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Loss of fuel in
per cent.
against the
theoretically
lowest pos-
sible quantity
90
60
45
36
30
26
23
20
18
16
15
14
13
12
It is not possible to tell from the appearance of the fire in the
furnace the percentage of C0 2 .
As one pound of carbon requires a minimum of 11 J pounds of
air for perfect combustion, it will produce 12 J pounds of total
furnace gas, and of this 3| pounds will be C0 2 : that is, fully
29 per cent, by weight or nearly 21 per cent, by volume. For
anthracite coal free from hydrogen the excess of air can be
calculated from the percentage of C0 2 in the flue gas.
For fuels containing hydrogen, the analysis being done cold,
the steam which is produced by the hydrogen is therefore not
measured, this steam is less in volume than the nitrogen of the
air which supplied oxygen to burn the hydrogen. The per-
centage of CO 2 in the flue gas thus appears smaller with the
more hydrogenous fuels than it does with the less hydrogenous
fuel. But in every case the actual percentage can be calculated,
and, once known, subsequent records can be compared with
the calculated datum line.
A fuel containing hydrogen to the extent of one per cent,
demands 55-9 litres of oxygen per kilo, of coal, or 0-9 cubic
foot per pound, to satisfy the hydrogen.
The following tabular numbers give the volume of oxygen per
kilo, and per pound of coal for various percentages of hydrogen.
Per cent. Litres per kilo. Cubic ft. per Ib.
1 55-9 0-9
2 112-0 1-8
3 168-0 2-7
4 223-0 3-6
5 279-0 4-5
6 336-0 5-4
7 391-0 6-3
8 446-0 7'2
9 504-0 8-1
10 559-0 9-0
11 615-0 9-9
12 672-0 10-8
13 .... . . 727-0 11-7
14 782-0 12-6
15 837-0 13-5
16 892-0 14-4
STORAGE AND DISTRIBUTION OF LIQUID FUEL 235
In calculating the volume of dry gas from analysis, any
hydrocarbon gas is calculated as though it were simply carbon
vapour of a weight of 1-072 grams per litre.
At 0C. and 760 mm. pressure,
Molecular weight
1 litre of CO 2 = 1-966 gram = 44.
1 CO = 1-251 =28.
1 C vapour = 1 072 = 12.
Each volume of C0 2 contains -rr of its weight of carbon, or
1-966 x f\ = 0-536 grams per litre. Similarly, the proportion
of carbon in carbonic oxide is f of the weight, or 1-251 X f
0-536 grams per litre, the weight of carbon vapour being 1-072
grams per litre.
Thus the total weight of carbon is C = 0-536 (v + v') -f
1-072 v" where v, v' and v" are the volumes of C0 2 , CO, and
carbon vapour in litres per each cubic metre or per 1,000 volumes
of flue gas.
For British units the formula becomes C =0-0335 (v + v')
+ 0-06693 v" where v, v' and v" are the volumes in cubic feet
per thousand feet of flue gas.
Kent's formula for the weight of dry gas per pound of carbon
is
_11, C0 2 + 80+7 (0+N)
3 (C0 2 + CO)
Having found this weight of dry gas from the analysis of the
furnace gases, there must be added the proportion necessary
for the steam produced. This will measure 9 by weight for
each unit weight of hydrogen, and, the density of steam being 9,
the relative volume may be found, or it may be taken from the
above table.
By formula the total volume of gases thus becomes.
C
=
0-536 (v+v')+ l-072v" ' >
where H is the percentage of hydrogen in the fuel, and A is the
combined volume of nitrogen and excess of air.
In analysing a furnace gas there are two main methods.
One is to take frequent samples rapidly in a bottle and analyse
this by the Orsat apparatus : the other is to take a sample,
known as a long sample, by means of a modification of the
Sprengel pump, the time of filling the sample bottle being
extended to any duration wished, even several hours. The
236 LIQUID FUEL AND ITS APPARATUS
analysis of this long sample gives the average furnace per-
formance over the whole time. Short samples may be taken
and analysed throughout the period of taking the long
sample.
For these analyses the Orsat apparatus may be employed
as most convenient. A description of this will be found in the
author's work on Liquid Fuel and its Combustion and in manuals
on gas analysis. There are numerous instruments devised
automatically to analyse flue gases so far as their contents of C0 2
is concerned. The Arndt apparatus keeps a continuous record
of the density of the gases whence the percentage of C0 2 is
shown by a pointer, and it may be arranged to show a
continuous record. The Ados apparatus actually analyses
small samples of the gas every few minutes, and records this on
a paper band. The apparatus of Simmance and Abady does
the same thing in a very simple manner. Descriptions of the
working of these instruments can be had from the makers.
Calorimeters.
While the calorific value of a fuel may be calculated approxi-
mately by Dulong's and other similar formulae, experiment
must be resorted to for more exact determinations. For
this purpose a sample of fuel must be actually burned in a very
complete manner and the heat must be measured which is
given off.
Essentially all calorimeters consist of a vessel in which
a small sample of the fuel to be tested is burned by a stream
of oxygen. The whole of the heat produced is absorbed by
water contained in an enclosing case and the calorific power
is calculated from the rise of temperature of the known
weight of water and of the metal of the instrument. Various
corrections have to be made and accurate results are only to
be obtained with great care. But if a number of samples are
tested under similar conditions, their comparative values
may be approximately determined without going to the
trouble of making corrections which will affect all samples
alike.
Descriptions of calorimeters and their method of use may be
found in the Author's book on Liquid Fuel and its Combustion,
and in other works on fuel.
The following table gives the calorific power of a few oiLs
and tars.
STORAGE AND DISTRIBUTION OF LIQUID FUEL 237
CALOBIMETBIC VALUES BY BEKTHELOT MAHLER CALORIMETER
ELEMENTARY ANALYSIS.
Character of Combustible.
Carbon.
Hydro-
gen.
Oxygen.
Nitrogen.
Calorific
Value.
Heavy oil from American
Cals.
petroleum
86-894
13-107
10,912-7
Refined American petroleum
85-491
14-216
0-203
11,045-7
Treble refined American
petroleum ....
80-583
15-101
4-316
11,086
Crude American oil
83-012
13-389
3-099
11,094-1
Heavy Baku oil
86-700
12-944
11,804-6
Novorossisk petroleum,
Caucasian
84-906
11-636
9-458
10,328
Tar from hydraulic main .
89-910
4-945
5-145
8-9428
Tar from cooler
87-222
5-499
6-279
8-8310
Tar from condenser
85-183
5-599
9-218
8-8384
With oil fuel alone the question of draught is of compara-
tively small importance, for the grate and its load of fuel form
the chief resistance to draught when solid fuels are used.
The draught due to a chimney arises from the differ-
ence of pressure of two columns of gas of the height between
the grate surface and the chimney-top. The column inside the
chimney is hot because of the furnace through which it has
passed. That outside the chimney has the temperature of
the outer atmosphere. At a temperature of 300C. (572F.)
the inner column is just about double the absolute temperature
of the outer column, so that the relative density is one-half.
The velocity of flow of a gas under any head is v =. \/2g h>
where v is the velocity in feet per second, h is the head in feet,
and 2g = 644 or gravity X 2. Gravity = 322.
Expressed in metres values of v and h we have v = \/2 g h,
where g =9-81.
Assuming that at ordinary temperatures 13 cubic feet of air
weigh one pound, the atmospheric pressure of 2,115 pounds per
square foot represents a column 27,495 feet in height, which
would flow into a vacuum at a velocity of approximately
8V27,495 = 1,321 feet per second.
The pressure to produce draught, however, is only measured
by inches of water pressure. If a chimney has an internal
absolute temperature double that of the external atmosphere,
it will contain only one pound of gas for each 26 feet of a
column of gas 1 foot square, or, what is the same thing, the
external column is half-balanced only. Thus if H be the height
of the chimney, H -i- (2 x 13) will give the pressure per square
foot, producing draught. Thus a chimney of 104 feet will
238
LIQUID FUEL AND ITS APPARATUS
give an acting pressure of 4 pounds. As 1 inch of water gives
a pressure of 036 pounds per square inch, the draught pressure
of the above chimney would be
= ' 7716 i
144 X- 036
Having found the pressure, the air column equivalent to
this must be found. Water weighs 624 pounds per cubic foot.
Air weighs 0-077 pounds, whence the equivalent air column, in
feet per inch of water column will be found.
624
12 X 0-077 =
The velocity of flow is then 8 A/67 H or fully 64 VH where H
is the"pressure in inches shown by the actual water gauge. In
coal-fired furnaces the reading of the draught gauge is much
greater at the chimney base than in the flues, for the friction of
the flues exerts considerable resistance. The simplest form of
water gauge is a bent glass tube of U form, one end being open
to the atmosphere, the other connected by a piece of india-
rubber tubing to a piece of pipe which enters the flues at the
point where the draught intensity is sought.
It is convenient to remember that where the velocity of
flow due to head in feet is v=V2gh, that due to a pressure
as shown in inches of water is almost exactly z=2gVH. All
these figures can only be approximate, because they will
vary with the temperature. They are sufficiently accurate
to base designs upon in respect of providing sufficient openings
for air to burn the oil.
The following table of velocities of air for a few pressures in
inches of water will be useful
Pressure in
inches of water.
Velocity of air in feet.
Per second.
Per minute.
0-1
20-7
1,243
0-2
29-3
1,758
0-3
35-8
2,150
0-4
41-4
2,485
0-5
46-3
2,778
0-6
50-7
3,043
0-7
54-8
3,287
0-8
58-5
3,513
0-9
62-1
3,726
1-0
65-4
3,927
2-0
92-4
5,547
STORAGE AND DISTRIBUTION OF LIQUID FUEL 239
An ordinary U gauge is not capable of being finely read.
It possesses a capillarity which is difficult to allow for and will
not serve for accurate work. A better gauge consists of a
glass-fronted box in two divisions partly filled with water.
A hook gauge, reading on a scale, permits very accurate mea-
surement. Descriptions of this and other gauges may be
found in the Author's larger work and in other works on solid
fuels. But since with solid fuels the greater part of the draught
is used in overcoming grate resistance the question is of com-
paratively small importance where liquid fuel alone is em-
ployed, since unencumbered furnaces and flues with a short
chimney appear capable of carrying away all the gases from
liquid fuel.
In coal firing, about three-fourths of the draught is swal-
lowed up by grate and fuel friction. With oil firing alone
and no grate friction there is usually ample velocity of the in-
flowing air. The chimney, in fact, ceases to possess so much
importance, but must be large enough in area to carry off the
waste gases.
The weight of a cubic foot of air at 0C. = 32F. being
0-08 lb. 5 that at any other temperature will be
0-08 x 273
973 -L / wnere 1S expressed in degrees Centigrade
, 0-08 x 491
and - where t is in degrees Fahrenheit.
By these formulae may be calculated the weight of air inside
and outside a chimney. The difference of the two is the
pressure to produce draught per foot of chimney height.
Calling D and d the greater and less densities the equivalent
height of a column for any chimney of height = h ft. will be
L = h (2=?) and the velocity of flow per second will be
v = V% g L where L is the equivalent column in feet.
In all the foregoing the specific gravity of furnace gas is
assumed equal to that of air of the same temperature, the
steam balancing the carbonic acid more or less closely.
Seeing that draught is of less importance with liquid fuel,
it is permissible to reduce the furnace products to a lower
temperature if facilities can be had for doing this. The smaller
excess of air with which perfect combustion can be secured is
a factor in rendering more efficient the heating surfaces of the
boiler, and reduced flue gas temperatures are a natural con-
seqence of liquid fuel.
A chimney must be large enough to pass all the products of
240 LIQUID FUEL AND ITS APPARATUS
a furnace at a certain given velocity of flow. The calculation
of chimney area is thus simple. Assuming the velocity of flow
of gas to be 30 feet per second, it is simply necessary to divide
the volume of gas produced per second by 30. The result is
the area in square feet of the chimney. To find the volume
of gas produced per second, the fuel consumption per second
is first found as follows in pounds
W X 2 240
P = fj ------ 'oV wnere W * s the daily consumption in tons
and H the daily hours. Then P x 20 = pounds of gas = G.
At ordinary temperatures one pound of gas measures 13 cubic '
feet very closely. At the chimney temperature it will measure
20 to 25 feet. Let 22 be assumed : then G x 22 4- 30 will
give the area of the chimney inside =A. The chimney will
measure, if square, VA, on each side, or, if round, its diameter
will be D = 1-128 VZ.
With oil a very small draught will draw in enough air for
perfect combustion, and it is usually necessary rather to check
the flow of the gases through the flues, only sufficient' draught
being required to remove the products of combustion as formed.
Chimneys of small altitude will do this, for they do not require
to overcome any grate or fuel-bed resistance. In locomotives,
tor example, the steam blast may be considerably reduced,
and on the Great Eastern Railway of England the MacAllan
variable blast-pipe is enlarged from 5 inches with coal to 5J
inches diameter with oil to the reduction of the back pressure
on the pistons and economy of steam in consequence. In
foreign locomotive practice it is usual to employ caps over the
chimney-top in order to save the loss of heat when running
down grade or standing idle. Mr. Urquhart continued to use
this cap with his oil-fired engines, and though it presents an
odd appearance to English eyes, the cap has advantages.
Applied to stationary work it is represented ordinarily by a
damper at the chimney-base, and is thus recognized as good,
but it is not used in locomotive work. It affords a ready
means of regulating the fires, and cannot quite be replaced
by the ash-pit damper, which is heavier to work and is by no
means always so tight-shutting as it should be.
A very usual remedy for a bad draught in coal-fired furnaces
is a steam jet. In oil-firing this aid to draught is present in
the atomizer, which really replaces the need for a certain
chimney or fan effect. The area of chimneys must not be
calculated from the horse-power to be developed. The actual
STORAGE AND DISTRIBUTION OF LIQUID FUEL 241
fuel consumption should be worked from. The fuel per horse-
power hour will vary according to the load-factor and other
conditions, and large stations will use less fuel per horse-power
hour than will small stations with smaller load-factors. Each
case must stand by itself. A very small draught will give a
velocity of 30 feet per second. Ordinary rules for chimneys
provide for areas that will reduce the velocity of flow to much
less than the foregoing 30 feet per second, but it is doubtful if
such large areas are necessary with liquid fuel, and it is certain
that a chimney hitherto used for solid fuel will serve well when
a change is made to liquid fuel. Experience so far is lacking
on the question of chimney practice for liquid fuel work, but
the subject may be approached from the standpoint above,
viz., that with liquid fuel not only is the resistance of the fuel
on the grate eliminated but there is added a propelling force
in the atomizer which, if applied to a poor draught hi a coal-
burning furnace, would render such draught good and sufficient.
Bearing these points in mind, the ordinary treatises on draught
may be studied with advantage as regards the effect of height
upon velocity of flow. But the ordinary rules otherwise have
little application to liquid fuel conditions.
CHAPTER XVII
COMPRESSED AIR AND AIR COMPRESSORS
THE use of air as the atomizing agent has been delayed
because steam is more readily obtained, and where
the loss of fresh water in the form of steam is not a serious
matter, it is claimed that steam is a cheaper agent than air,
which must be compressed by steam power to begin with.
But steam is not a supporter of combustion, and air is ; and
there is a tendency to-day to employ air where possible,
and to use it hot. Air being so nearly a perfect gas, the whole
work of compressing it is practically converted into heat,
and the temperature of the compressed air is raised. In the
compression of air to 60 pounds per square inch or more it is
usual to compress in two stages, cooling both cylinders by means
of a water jacket, and cooling the air between the two stages by
means of a tubular receiver or a sufficient area of exposed
tubes. But in fuel atomizing a pressure of 15 pounds to 20
by gauge is usually held to be ample, and generally it is not
necessary to use air at the same high pressure as steam. Air is
much heavier than steam, and more energetic per unit volume.
But this does not apply to air which must of necessity be intro-
duced into the furnace and is required for the proper combustion
of the fuel. Air compressors are somewhat awkward machines,
and, especially on shipboard, are not easily housed. For oil
atomizing it is not necessary to employ a two-stage com-
pressor. The heat of compression is not great for the first
moderate stage of 15 to 30 pounds, and after the air leaves the
compressor it should be heated on its way to the atomizer.
This is usually effected by means of pipes in the flues of the
stationary boiler or in the smoke-box of the locomotive.
The curve of isothermal compression of a perfect gas is the
hyperbola, the equation to the curve being such that Pv =
constant.
Thus two cubic feet at 40 pounds absolute pressure become
one cubic foot at 80 pounds, but the temperature remains
constant.
242
COMPRESSED AIR AND AIR COMPRESSORS 243
When air is compressed adiabatically, or without loss or
gain of heat, its curve has the equation
P
P
P being the pressure corresponding to the small volume v,
and V the volume at small pressure p.
Assuming the volume v = I we have
p V 1- 403
_____ or P = # V 1 ' 408
p 1
Thus air at pressure p =15 is compressed to P = 90.
p
Then = 6 and the relative volumes before and after com-
P
pression are for v = 1.
yi-403 p
The log. of 6 is 0-77815
and 0-77815 4- 1408 = 0-55266, which is the log. of 3-57 = V.
Thus in place of an original 6 vols. of air, only 3-57 will be
needed to give a final volume of 1, owing to the increased
volume due to temperature rise. For a moderate compression
of 2 only we shall have V 1 - 408 = 2. The log. of 2 is 0-30103
and 030103-^ 1408 = 0-2138, which is the log. of 1-636,
this being the number of compressions necessary to give a
double pressure instead of two compressions, had the tempera-
ture been kept down or V = 1-636.
The heat generated in compressing a gas from a pressure of p
to a pressure of p L is
>
where, 7, according to Rankine, is 1-408; p and p are the
initial and final pressures in atmospheres and H = foot-pounds,
T being the absolute temperature whence the heat units per
pound of air compressed will be H -f- 772, and the temperature
TT
0-237 being the specific heat of air.
The work done in compressing and delivering one pound of
air is thus, in foot-pounds
244
LIQUID FUEL AND ITS APPARATUS
Fig. 63.
whence can be found the power required for compression. The
efficiency overall from motor switch-board should not be taken
above 70 per cent, when
designing a motor for the
purpose. The overall
efficiency of a first-class
air compressor is said to
exceed 70 per cent, with
its electric motor, but or-
dinary compressors cannot
be calculated above 50 per
cent.
Since free air weighs
one pound for each cubic
13 feet at ordinary tem-
peratures, the size of com-
pressor required for any a
weight of air is easily
calculated from the speed
and piston displacement.
In a water-cooled compressor the index of the curve of com-
pression of a good compressor may be safely taken at 7 = 1 -2
in place of 1-408, as in adiabatic compression.
The subject of air compression is one of such importance in
respect of liquid fuel combustion as to justify full explanation
of the peculiar action of a perfect gas.
Air is so nearly a perfect gas that there is very little internal
work done upon it when
it is compressed. All
the work appears as
heat. In Fig. 63 this
action is shown dia-
gramatically. A volume
of air a b at the pres-
sure b n of one atmo-
sphere, if compressed
to several atmospheres
so slowly that it loses all
the heat of compression
at once, will occupy a
volume c d at the pres-
sure a c.
The area a b n i will
in other words, the
Fig. 64.
be exactly equal to the area a c d m ;
product of pressure and volume is constant.
COMPRESSED AIR AND AIR COMPRESSORS 245
If compressed quickly, without loss of heat, the curve n k
will be described and the volume of the compressed air will be
c k. The rectangle d a is equal to the rectangle a n for d and n
are points in the isothermal curve n d. Consequently the
rectangles d i and m n must be equal and n k c i is equal to
m b n k d, or, in words, the mechanical work of adiabatic com-
pression is equal to the work done in compression and delivery.
If, in place of single-stage compression, the double-stage
system be adopted, the principle of intermediate cooling can
be employed. Thus, in Fig. 64 compression is first carried to
the point o ; the compressed air is cooled in the receiver to
the point j, and arrives at the ultimate pressure a c with a
volume very little greater than c d. The diagram is less in
area than Fig. 63 by the area j o k q, and this represents energy
economized during compression.
These same principles and arguments may be applied to the
use of air in two stages in place of one. Thus, the compressed
air may be made to run a pump the exhaust from which is
carried to a hoisting engine or other motor.
When compressing air the heat of compression is dissipated
to the atmosphere, and when the air is used again in a two-
stage expansion it is reheated between the stages by absorption
of heat from the atmosphere, which thus serves the part of a
general equalizer, absorbing heat from compressed air and
giving it out again to expanding air.
It is stated by Lieutenant Winchell that tests made on vari-
ous atomizers show that each pound of water evaporated
from and at 212F. requires one cubic foot of free air compressed
to 20 Ib. gauge pressure =35 Ib. absolute. Assuming that
1 Ib. of oil will evaporate 13lb. of water, and that 13 cubic feet
of air are equivalent to 1 Ib., the figures represent 1 Ib. of air to
atomize 1 Ib. of oil. How much power, then, will be required
to atomize the fuel for 1,000 h.p., using, say, 16 Ib. of steam
per h.p. hour, with an evaporation, say, of 14 Ib. per pound of
oil? Here 1,000 x |J =1,143 Ib. of oil per hour, or 1,143
Ib. of air. This is 19 Ib. of air per minute, to compress which,
according to equation (2) adiabatically from a temperature
of 62F.= 522 absol., will require per pound of air
per pound of air compressed to 20 Ib. gauge pressure per minute.
At 70 per cent, efficiency, this becomes 1-2 h.p. nearly, or a
246 LIQUID FUEL AND ITS APPARATUS
total of 22-8 h.p. for the total engine power of 1,000, which is
less than 2J per cent, of the total power ; whereas steam ato-
mizing requires 3 to 5 per cent, of the total power of a boiler.
The citation of the air per pound of evaporation is hardly
a correct method, but not much is yet known of this part of
the subject, and meantime one pound of air, or 13 cubic feet
of free air, should be provided per pound of oil ; and probably
with the cooling effect allowed for, one brake horse-power will
compress one pound of air to 20 pounds gauge pressure. The
figures thus confirm M. Bertin's orginal ideas, as given below.
The above calculation is for adiabatic compression.
Per kilogram of air per minute the power expended in air
compression will be nearly 50 h.p.
To spray one kilo, of oil requires 28-6 cubic feet of free air,
or 812-0 litres. As it. is usual to order air compressors by their
capacity in cubic feet of free air, the amount of one unit weight
per unit of oil works out at 13 cubic feet per h.p. hour, more or
less, according to the efficiency of steam engine and boilers, or
from 20 to 25 cubic feet per minute per 100 h.p. From this
the size of air compressor can be calculated.
Thus an air compressor will have, say, a total useful piston
stroke equal to 3 feet per revolution. At 240 revolutions per
minute, this represents 720 linear feet. With 10 inch dia-
meter pistons the capacity is thus about 390 cubic feet per
minute, less, say, 10 per cent, for slip or 350 cubic feet, which
should supply about 1,400 to 1,700 h.p. of burners in a fairly
economical plant. An allowance of ten per cent, for slip is
enough in these compressors for 80 pounds compression, and is
therefore more than ample for ordinary low pressure work.
The compressor lends itself readily to electric driving. Auto-
matic regulating devices are fitted to maintain the air pressure
constant in the case of electric driving by rheostatic control
actuated by the air receiver pressure.
M. Bertin, of the French Navy, states that a good compressor
will not use half the steam that is used where steam atomizing
is employed, for steam will compress more than its own weight
of air up to its own pressure ; and it can hardly be doubted that
for naval and marine purposes generally the use of air for
atomizing must eventually become general.
In the foregoing calculations the compression of the air has
been assumed to be adiabatic. This is not strictly correct
even in uncooled cylinders, and some distance from correct-
ness in cooled cylinders, but any error is on the right side, and
it is better to proportion the air compressors on an adiabatic
basis, so that there may be a fair allowance of power.
COMPRESSED AIR AND AIR COMPRESSORS 247
As already stated, where the index of the adiabatic curve is
y = 1 4, and that of the isothermal curve is y = 1 -0, practical
work may be done at values of y = 1-2. Expanding air be-
comes so very cold that between the compressor and the ato-
mizer air should be heated as hot as possible, in order to
counteract the chilling effect.
For compound compressors, which so far hardly come into
the sphere of liquid fuel work, the power required to compress
up to an absolute pressure of 2, 4 or 6 atmospheres is as follows,
compared with adiabatic compression in a single-stage machine
Pressure in Atmospheres.
Absolute.
Ratio of Power.
W 2 ; Wi.
Probable Ratio
in practice.
2
4
6
951
901
871
975
950
935
Even in single-stage compression the actual power required
in a cooled machine will probably be about midway between
the figures for adiabatic and two-stage intercooled work.
See column 3 above.
As explained elsewhere, the economy of cooling is doubtful ;
though if there are suitable means of heating the air, it is ex-
pensive to heat it by expending power upon it.
In the following table is given the horse-power necessary to
compress one pound of air to 2, 4 and 6 atmospheres pressure
absolute from the ordinary temperature of 60F. 15-5C.
The figures are for adiabatic compression of one pound per
minute
Absolute
Atmospheres.
Horse Power.
Actual h.p. of
driving motor.
Gauge Pressure.
2
4
6
0-645
1-433
1-972
0-860
1-911
2-629
14-7 Ib.
44-1
73-5
The difference between adiabatic and isothermal compression
is of no serious account up to 30 Ib., or even to 45 Ib. The
volumetric efficiencies of good compressors at these low pres-
sures may be safely taken at 90 per cent, of the piston displace-
ment. The efficiency of the machine being, say, 75 per cent,
overall from engine to compressor, the indicated horse-power
actually required will be found by adding one-third to the
figures in column 2, whence is found column 3.
Apparently, therefore, air for atomizing may be compressed
by one horse-power to the extent of about 60 pounds weight per
248 LIQUID FUEL AND ITS APPARATUS
hour. Now, one horse-power in a good steam engine will con-
sume, say, 16 Ib. of steam per hour, or, say, 20 Ib. per electrical
horse-power hour, so that under favourable circumstances 1 Ib.
of steam should compress 3 Ib. of air ; and air should, appar-
ently, be the better agent to employ, quite apart from the
advantage at sea of not wasting fresh water. Further experi-
ment is, however, required to afford reliable and fuller figures
before a hard and fast ruling can be even attempted. The
Author's own opinion is in favour of air heated to a considerable
temperature and more or less charged with moisture to assist
in preventing fouling of the atomizers.
Flow of Air.
Mr. D. K. Clarke gives the velocity of air flowing from any
pressure P into any other lower pressure of not more than f
of P as 880 feet per second.
Actual experiments upon orifices having a length greater than
their diameter give about 750 feet per second.
The following results were obtained
50 Ib. gauge pressure blowing through f" nozzle to atmosphere 775 ft.
30 |" =725
45
16
25
7
25
r
r
= 778
= 725
= 748
= 898
= 675
The last two results were doubtful.
It will be safe to count upon a velocity of 750 feet in making
calculations as to the weight of air which will pass an orifice.
The above velocities are calculated, of course, on the air at the
higher pressure. The weight of air is proportional to the ab-
solute pressure, twice as much air escaping at 35 Ib. gauge pres-
sure as at 10 Ib., that is to say at 50 Ib., and 25 Ib. absolute.
On the relative economy of air or steam for atomizing, Pro-
fessor WiUiston says unquestionably that air at 2 to 5 or even 10
pounds per square inch is more economical than steam, so
far as the spraying is concerned. At higher pressures there
is a doubt as to economy, for the cost of compression increases
rapidly with the pressure, and the atomizing capacity of the
air does not increase at the same rate. Thus in the U.S. Navy
tests the most economical results were found with air pressures
of only one or two pounds. All atomizers will not work at this
pressure. At these low pressures, however, less than two per
COMPKESSED AIR AND AIR COMPRESSORS 249
cent, of the steam generated would compress the air. At an
air pressure of four or five pounds, four per cent, of the total
steam was required to compress the air. Obviously, where
atomizers will act satisfactorily, it will be advantageous to use
much air at a low pressure in order that the combustion may be
improved, for air must enter the furnace, and in air atomization
there is not the risk of fire extinguishment that there is with
steam.
CHAPTER XVIII
THE ATOMIZING OF LIQUID FUEL
SINCE liquid fuel of the heavy varieties cannot be burned
except by atomizing, the burner, injector, sprayer or
atomizer, as it is variously termed, is an important detail.
Its object is the pulverizing of the liquid, so that, mixed with
air in the act of pulverization, and supplied with any further
amount of air that may be necessary, the liquid atoms may
burn like vapour.
The spray must not be so directed than an intense blow-pipe
flame impinges severely upon any small area of furnace plate.
It is sought to fill the furnace with a full soft voluminous flame
which shall envelop its whole interior. Given a sufficiently
long space in front of the burner, a spray directed straight
ahead and coning out would doubtless produce a satisfactory
effect, but the space between the point of the burner and that
part of the cone of flame which first touched the furnace plate
would be of little use as heating surface. What should be
aimed at is such a burner and spray device as will produce a
certain disrupture and outward expanding effect, so as at once
to spread the oil to a considerable extent normally to the axis
of the burner as well as parallel ; to give a sort of balloon effect,
so that, in a locomotive boiler for example, there shall be
flame well to the back of the box as well as forward under the
arch. Various forms of atomizers will be found illustrated in
this or earlier chapters, including
The Holden (Figs. 23, 24 and 25). The Billow (Fig. 44).
The Baldwin (Fig. 34). The Aerated Fuel Co. (Fig. 67).
The Urquhart (Fig. 42). Kermode's Burners (Figs. 68,
The Hydroleum Co. (Fig. 71). 69).
The Swensson (Fig. 73). Orde's (Fig. 15).
The Guyot (Fig. 75). Korting's (Figs. 21, 21a).
The Rusden and Eeles (Fig. 66). The Hoveler (Fig. 65), p. 287.
The Holden Atomizer.
The Holden Injector (Figs. 23, 24, 25) consists of a gun-metal
casing with oil, air and steam inlets. Air comes in at the back,
250
THE ATOMIZING OF LIQUID FUEL
251
preferably hot, and is delivered at the point where the oil
escapes to the inner nozzle. Steam comes between the oil and
air, and the mixed jet escapes forward and slightly laterally by
two orifices. A further air supply is directed upon the spray by
a ring of several fine jets of steam. The atomized fuel is direc-
ted along the plane of the fire when the fire-bars are retained,
as this gives the best action. Mr. Holden does not confine
himself to the use of steam as an atomizing agent, but recognizes
that air may be preferable for chemical reasons. Two burners
deal with about six pounds of oil each per mile, or, say, 240
pounds her hour.
LU
Fig. 66. ATOMIZER. RUSDEN-EELES.
Eusden and Eeles.
In this burner Fig. 66), steam escapes by a central annular
jet, and is directed outwards on a fine annular jet of oil, which
is heated also by a steam jacket. This disposition gives a
balloon flame. The burner is largely used in marine work.
The Urquhart.
This (Fig. 42), one of the earliest successful atomizers,
employs central steam, external air, and an annular oil jet
between the two, the expansion of the steam atomizing the oil
into the air and mixing the two.
252 LIQUID FUEL AND ITS APPARATUS
The Baldwin (Fig. 34).
The burner is very simple, being simply a broad thin jet of
steam which is directed upon oil escaping from a parallel
passage. It could not well be simpler, but it is claimed to
act well, and there appears no reason to doubt this.
The Aerated Fuel Company's Burner.
This is of the central air jet type, as shown in Fig. 67.
Fig. 67. ATOMIZER. AERATED FUEL SYSTEM.
The Kermode Burners.
The latest type of Kermode burner is the pressure-jet burner
specially designed for naval and other vessels, and recommended
for use with forced or induced draught. The burner is shown
in longitudinal section and in plan respectively in Fig. 68.
The oil enters through the channel A, and passes between
the outer wall D and the inner cylinder B, which abuts against
THE ATOMIZING OF LIQUID FUEL
253
the cap-nut E. The end of the cylinder B is an exact fit in D
where it abuts against the nut E, and in this end of B a number
of grooves are cut parallel to the centre line of the burner,
while there are similar grooves in the end of the part B at right
angles to the axis of the burner. These grooves are shown
at H, and they are tangential to the cone end of the spindle
C, which serves to contract, or enlarge, the opening through
the cup-nut E. The movement of C is indicated on the gradu-
ated wheel F.
The oil fuel is pulverized by being forced through a restricted
Fig. 68. ATOMIZER. KERMODE'S PRESSURE SYSTEM.
opening with a rotary motion, which is given to it by the
tangential grooves in the face of the plug B, and it is distributed
in the form of a cone by means of the reaction or deflection
which is set up by the oil impinging on the cone end of the
spindle C, the pulverization being effected by means of the
pressure which is brought to bear upon the oil fuel itself by
means of a force-pump. The oil is heated and filtered. The
fixed pointer marked G serves to indicate the degree to which
the wheel F has been rotated, to increase or diminish the
opening through the nut E.
Fig. 69 shows a section of the latest Kermode hot-air burner.
In this burner the oil is partially vaporized and sprayed by hot
air at a pressure of half to four pounds, the industrial furnace
working with the former pressure and the naval boiler calling
254 LIQUID FUEL AND ITS APPARATUS
for 3 to 4 Ib. Oil enters at A, and is regulated by the
wheel E and the valve on spindle D. Hot air enters at B
and C and the long helix K gives a rotary motion to the oil and
air and insures that none of the oil vapour will pass through
the tube untreated. The supply of air can be regulated at two
points by means of hand wheels, pinions, and racks ; one pinion
L moves the internal tube over the oil-delivering nozzle F,
and regulates the air which enters there. The second pinion
M operates the outer tube, and varies the amount of air
escaping around the mixed jet at the end of the twisted spindle
K. All the elements of the combustion are under complete
control. The oil as it trickles from the nozzle beyond the valve
is swept forward by a sharp current of air which envelops the
nozzle ; this current can be regulated with great exactitude.
A further compressed air supply is given where combustion
Fig. 69. ATOMIZER. KERMODES HOT AIR SYSTEM.
is about to commence, while a third supply is caused by the
induction of the flame or by the draught ; this latter supply
comes through the fire-bars, and in special cases through a
hollow furnace front, passing between the inner and outer
plate, and escaping through a coned opening around the burner.
No change in the arrangement of the furnace as designed for
the use of coal is necessary, and to equip the furnace for burning
liquid fuel it is only necessary to cover the fire-bars with broken
fire-bricks to a depth of from 6 to 8 in., the greater depth
being towards the bridge. The burners are arranged to hinge
on the air and oil cocks which are attached to the boiler, and
if it is necessary to examine the front of the burners they can be
withdrawn from the furnace, the act of withdrawing shutting
off the supply of air and oil, and thus preventing accident.
Fig. 70 shows the steam and induced air burner. The oil is
pulverized by a jet of steam. Oil enters centrally through
the branch B, and has a whirling motion imparted to it by the
THE ATOMIZING OF LIQUID FUEL
255
stem of the oil valve G. Steam enters around the hollow cone
H, passing through slots in the cylindrical portion where this
fits into the hollow of the air cone, the whole oil supply is thus
steam- jacketed. The air cone is F, and this is also fitted with
spiral guides. The air is drawn in through these guides by the
inductive action of the steam, its amount can be adjusted by
N
Fig. 70. ATOMIZER. KERMODE'S STEAM SYSTEM.
opening or shutting the openings D, by means of the movable
perforated strap E. The front portion F is arranged to screw
in or out as a whole, being turned by the spider M. In its
motion it carries with it the air cone F, and thus leaves a greater
or less space between this and the oil cone H, for the escape
of steam. The range of adjustment is large, and the same
burner may be used for different powers within wide limits.
The fydroleum
Fig. 71. ATOMIZER. HYDROLETJM SYSTEM.
Fig. 71 shows the nozzle of the Hydroleum Company's burner.
Oil is centrally regulated by a needle, and issues from a mouth-
piece flared out externally in such a way as to direct the atom-
ized spray slightly outwards, the oil being in the middle. The
oil mouthpiece is in advance of the steam, and an inductive
action is produced which draws the oil forward when communi-
256 LIQUID FUEL AND ITS APPARATUS
cation is opened with the reservoir. The Author has seen this
burner acting well with tar as fuel.
External hand wheels regulate the position of the oil and air
cones, and vary the amount of air allowed to escape round the
nozzle.
An elementary form
of atomizer consists
simply of two lengths
of gas pipe, one in-
Fig. 72. side the other for
the oil and steam.
In Fig. 72 this is shown developed somewhat, the steam pipe
being swaged, to form a jet, and drilled to admit the oil.
The flame of this burner is small, and produces intense local
heat, and must in boiler work always be accompanied by
plenty of suitable brickwork. This form is used in various
forms in South Russia.
Of self-atomizing oil- jets the Korting (Figs. 21 and 2 la) has
Fig. 73. SWENSSON ATOMIZER.
been considerably employed at sea, and is described under the
head of the Korting System, p. 153.
Another self -spraying oil- jet is the Swensson (Fig. 73), in
which the oil passes through a fine jet, and is divided into spray
by striking a cutter placed a little in front of the orifice. These
self-sprayers have a certain advantage of simplicity. No
THE ATOMIZING OF LIQUID FUEL
257
bulky air pump is required, to compress air, for atomizing the
oil. There is no waste of fresh water as in steam atomizing.
A small oil pump will spray all the oil of a large steamship, as
a simple calculation will show. With a horse-power of 5,000
there may be used 5,000 pounds of oil per hour, or, say, 10
gallons per minute, which would fill a three-inch pipe 400
inches long. Thus a three-inch oil pump with a six-inch
stroke, if run at sixty-
seven strokes per
minute, or, say, thirty-
four revolutions, would
feed oil for 5,000 horse-
power, and two or three
smaller pumps would in
practice be employed in
any ship. The oil
pumps are thus very
insignificant in size, and
this fact will popularize
the self-spraying ato-
mizers if they prove
satisfactory under ordi-
nary conditions. Of
course, the oil will not
spray unless heated
sufficiently to be limpid
and easily flowing. If
too viscous it will spray
in strings, and not burn
as thoroughly as it
should.
The Symon-House
Burner.
This is one of the
vaporizing burners
which use the paraffin
or kerosine grades of oil, a cellular reservoir above the flames
serving as the vaporizer through which the oil travels in a long
circuitous course, passing down the pipe to a turned-up jet
below, this being regulated by a needle, and surrounded by a
cone which conducts air to the flame. Preliminary heating
by a lamp of petrol or alcohol is necessary. This burner is
used for small launch boilers, and is shown in Fig. 74.
SYMON-HOUSE BUHNER AND
VAPORIZER.
258
LIQUID FUEL AND ITS APPARATUS
It is claimed that in small work atomizing produces too
intense a heat, and that vaporized petroleum is better. Steam
can be raised to 100 pounds pressure in twelve or fifteen min-
utes, and by means of the igniter above the vaporizer the fire
will relight after several minutes if put out by a sudden jar or a
gust of wind. The igniter consists of a hollow disc full of
broken fire-brick.
In the French navy the Guyot burner has been much used,
This is shown in Fig. 75, the oil entering centrally and being
impinged upon by an annular jet of air or steam. The atomiz-
Fig. 75. GUYOT ATOMIZER.
ing nozzle should not project as in Fig. 76, but should be kept
short, as in Fig. 77.
The Atomizing Agent. .
Though in the early French trials of 1887 as much as 1-2
pounds of steam was used per pound of oil, the quantity was
gradually reduced until, in 1893, less than half a pound of
steam was used in the Godard boiler, says M. Bertin, and in
1895 M. Guyot got down to as low as 0-25, results which also
have been obtained in the Italian Navy. Indeed, on a Schichau
torpedo boat as low as 0-102 is claimed.
Compressed air, said M. Bertin some years ago, has some
theoretical advantages, because a given weight of steam will
compress up to its own pressure a weight of air superior to
itself, and the pulverizing effect of a jet depends on the energy
THE ATOMIZING OF LIQUID FUEL
259
of the jet rather than upon its volume. Probably the resis-
tance of the machine overbalances any theoretical advantage,
but at sea the loss of fresh water, where a steam atomizer is
employed, must amount
to about 5 per cent, of
the total steam generated.
M. Bertin, however, said
that a good air compressor
will not use half the steam
necessary where this is
used direct. When start-
Fig. 76.
NOZZLE OF GUYOT ATOMIZER.
INCORRECT FORM.
ing from the cold boiler,
the compressed air may
be raised by a small
compressor driven from a storage battery, by a small petro-
leum engine, or by hand. Steam atomizing is open to the
objection that should priming occur the fires may be ex-
tinguished, and where the steam comes over wet, from a
priming boiler, it is quite common for burners to be ex-
tinguished, and the red-hot brickwork fails t j ignite the oil,
and it is necessary to do this by means of a flaming torch.
Steam should therefore be superheated, both to render it dry
and to improve its general action.
M. d'Allest found in VAude that atomizing by steam used
up 15 per cent, of the total steam produced. A little later,
at Cherbourg, the Torpedo-boat 22 used as little as 1-2 k.,
and the Buffle only 0-75 k., per kilo, of oil pulverized, until
finally the results as
detailed above were
secured, though actual
facts are not easy to
obtain, and tests require
to be undertaken with
a special boiler to supply
atomizing steam. Re-
sults of 0-5 and 0-7 are
frequently obtained, and
have gone below 0-3.
Such a figure as this is
to be considered very good indeed. To save fresh water at sea
is so much to be desired that could compressed air be substi-
tuted for steam it should be. M. Bertin, formerly favourable
to air as more economical, saw reasons to change his views.
Air was necessary at much higher pressure than that required
for forced draught. It is affirmed that 1-4 k. of steam at 6 k.
Fig. 77.
NOZZLE OF GUYOT ATOMIZER.
CORRECT FORM.
260 LIQUID FUEL AND ITS APPARATUS
pressure must be expended to compress 1 kilo, of air to 1*5 k.,
and more air must be expended to pulverize each unit of oil
as compared with steam. Thus Torpedo-boat 60 at Cherbourg
expended 0-6 k. to 0-8 k. of air in place of 04 k. of steam.
During a test at Indret not less than 0-5 k. of air was
expended. In brief, with ordinary apparatus to obtain 2 k. of
air, which is needed to do the work of 1 k. of steam used direct,
one must use 3 k. of steam in the compression engine.
The difficulty is that compression is slow in an ordinary
Fig. 78. BOILER or FRENCH TORPEDO-BOAT No. 22.
machine, and steam cannot be used economically, for the air
attains its highest pressure when the steam is ready to exhaust,
and a heavy flywheel is necessary to help the expanded steam.
M. Bertin is further impressed with the physical and chemical
advantages of steam, which, he affirms, secures the Ragosine
effect as utilized in the distillation of petroleum without crack-
ing, owing to a certain solvent action of steam on petroleum,
as yet little understood.
The particular form of the Guyot atomizer (Fig. 75) is that
of Torpedo boat No. 22, the furnace of which is shown in Fig.
78, the boiler being of return tube type. M. Bertin finds
THE ATOMIZING OF LIQUID FUEL
261
from French experience that though regulation of an oil
atomizer is most delicately effected by means of the central
needle of the feed water injector, yet a valve is a less delicate
detail, and many atomizers have no central moving cone,
but are regulated solely by valves.
It is necessary when atomizing that the steam should flow
at a certain speed. If too rapid, the flame is extinguished ;
if too slow, there is incomplete pulverization, and the oil escapes
in drops too large to burn well.
Hence the steam orifice must be regulated to suit the boiler
pressure. ^
The opening for oil should not be
less than 1 mm. = 2 V inch. If too
large the oil flows in too great a
quantity. It is essential that steam
or air and oil shall be capable of
regulation when at work, and that
the interior of the atomizer should
be readily removed while at work,
so that the orifices can be cleared
quickly and the whole replaced im-
mediately.
After numerous experiments with
atomizers producing both thin flat
jets, and thin annular or cylindrical
jets, M. d'Allest devised the atomizer
of Fig. 79, for which are claimed the
best results in regularity of effect
and steady working. It is very Fig 79 D > ALLEST ATOMIZER.
simple in form, and can be rapidly
dismounted for cleaning. It consists of an outer case con-
taining an inner cone and spindle ; a steam inlet at the
side N admits steam to the casing. The whole is attached
to a conical mouthpiece. Steam is regulated by a valve,
and escapes round the two cones, while oil comes round the
central spindle.
Air is induced through the surrounding opening E.
The cone can be screwed upon the nose of the case for par-
tial adjustment of the steam, which is further regulated by a
valve in the steam pipe. M. d'Allest places these vaporizers,
if necessary, in couples in one furnace, connecting them to the
same oil pipe to the number of three, or even four.
Each burner will dispose of from 10 to 80 kilos. = 22 to 176
pounds of oil per hour. Two burners, using each 80 kilos, of
oil, will evaporate 13 kilos, of water per kilo, of oil, or say 2,080
262 LIQUID FUEL AND ITS APPARATUS
litres per hour = 4,576 gallons. Allowing 30 litres per square
metre of heating surface ; about 6 pounds per square foot ;
these two burners should serve a boiler of 70 square metres of
heating surface or 753
square feet.
In a torpedo boat, how-
ever, the desired evapor-
ation exceeds this amount
per square metre. With
this in view, M. d'Allest
has designed a double
atomizer, in which oil is
admitted round the cen-
tral tube in an annular
jet. Steam comes out-
side this, and hot air is
induced round the whole,
the heating being effected
by a tube in the chimney.
This apparatus (Fig. 80)
will burn as much as 400
kilos. =880 pounds of oil
per hour without a trace
of smoke.
She am
Fig. 80. D'ALLEST DOUBLE ATOMIZER.
It was tried in VAude, one of the ships of the Compagnie
Frassinet. A weight of 120 kilos, of oil per hour = 264
pounds, produced 170 horse-power, the evaporation being 14-1
units of water per unit of oil, but the French Navy considered
12 units as the maximum that should be calculated upon.
FvardofsJci System.
This system applied to locomotives consists in the placing of
an atomizer in each wall of the furnace two and two exactly
opposite, the jets meeting centrally and promoting mixture.
The grate is covered with fire-bricks, between which air enters.
Though a special pulverizer was used, it would appear that
any atomizer could be arranged on this system.
The Brandt burner consisted of a circular box, with a tapered
slot all round it nearly closed by the edge of a disc. Steam
escaped under the disc and oil above it. The burner was set
in the middle of the fire-box and gave a large hollow flame, but
it had the disadvantage of being inaccessible when at work,
and the flame was easily extinguished, as by the slipping of the
THE ATOMIZING OF LIQUID FUEL 263
wheels of a locomotive, the sudden pull of the blast extin-
guishing the flame and chilling the box.
The Soliani burner (Fig. 81) is of simple form, resembling the
scent spray.
There are numerous other forms, some complex, others
crude, but to enumerate all would occupy great space, and
serve no good purpose. Those illustrated
will show the general trend of practice and
what has been done, the chief point being
apparently that the annular form of jet
is preferable and conduces to best mix-
tures.
The difficulty with burners which
vaporize has been the deposit of carbon.
This will occur even with kerosene, the Fig gl g OLIANI
carbon being a pulverulent coke. The BURNER.
difficulty was got over by M. Serpollet by
means of easily replaced burners. Heavy oils can then be
burned. Too high a heat seems to be the cause of carbon
deposit, the oil being " cracked " exactly as in a highly heated
still. At present not much is being done by vaporizers, at
least for large powers, the atomizer becoming more general.
On the question of pre-heating, the French Naval tests are in
accord with others as to the advantage of this.
Long recognized as an advantage to heat to 80C. = 176F.,
it is to-day established that Mazout may well be heated to 132
C. =269-6F.
At this temperature the fuel gives off a certain amount of
vapour, which raises the pressure in the burner, helps the
velocity of the jet, and ignites promptly at the nozzle, and
assists the combustion of the whole. Heating the oil raises
the efficiency of the combustion, cuts short the flame, and
increases the effect of the heating surface.
It is not desirable to generate too much vapour at the orifice
of the atomizers, or no air can gain access to the jet, and com-
bustion cannot occur. Air admixture is, of course, necessary,
and when atomizing is done with compressed air this is a mere
fraction of the total air required. The air itself is best heated,
especially if this can be done by recuperation of otherwise
wasted heat.
The object of an atomizer is to fill the furnace with flame, and
the furnace must avoid contact with the flame pending complete
combustion. The accomplishment of these various ends has
brought about the many forms of atomizers already described.
All of them bear a strong family resemblance. In Russia
264 LIQUID FUEL AND ITS APPARATUS
there appears a tendency to employ flat jets. Hence also the
various forms of furnace with their refractory linings of fire-
brick, as in Fig. 82 annexed, which represents a boiler made at
Cherbourg in 1893, and bears a general resemblance to the
much older forms devised by Urquhart. In this boiler the
atomizers are placed as shown in the side walls of the furnace.
Railway practice in America tends to the use of flat jets.
On the Southern Pacific Railway a simple atomizer, which
allows the oil to fall from an orifice over the front of a flat
steam jet, has this jet 3 J inches wide. The petroleum escapes
at an orifice half an inch high and of the length of three inches,
the steam opening being about 0-8 mm. high, or - 3 V inch. The
Fig. 82. LOCOMOTIVE TYPE BOILER TESTED AT CHERBOURG WITH LIQUID
FUEL.
width of the jet of steam is 3 J inches, extending J inch at each
end below the flow of oil, so that no oil escapes unatomized.
Flat pulverizers are stated by M. Bertin to be suitable for
boilers of the Belleville or Niclausse type, in which the flames
rise directly from the grate to the water- tubes. The broad
flat flame probably burns over a wide area, and does not enter
between the pipes so rapidly as if it were a less wide spreading
jet.
Should a pulverized jet encounter a cold boiler plate at a
temperature of 400 to 500C. 752 to 932F., the oil will
condense on the plate and not again ignite.
In the boiler of Torpedo-boat No. 22 (Fig. 78) the furnace is
fitted with an air advance chamber in which oil is atomized
and meets air streams admitted radially. The furnace is
THE ATOMIZING OF LIQUID FUEL 265
brick-lined, with a low striking bridge. In this boiler 11*6
kilo, and 10 -8 kilo, of water have been evaporated per kilo,
of oil with a draught of 20 to 30 mm. (1 inch mean) of
water. At heavier draughts of 95 to 1 10 mm. water gauge
(or a mean of four inches), only 9- 45 k. and 8-5 k. were
evaporated. A similar boiler, with the air arriving parallel
with the jet, however, evaporated 13-25 k. of water, which
shows the difference due to arrangements.
It may be stated finally, that, of all atomizers, the more
successful are those which atomize the oil right at the nozzle
or point of exit. This class appears least liable to choke with
dirt or to permit of the oil becoming carbonized within the
body of the atomizer.
Where atomizers are applied through the furnace door they
are arranged to swing back upon a trunnion hinge so designed
as to shut off the fuel supply when the atomizer is swung back.
The body part on which the atomizer branches are connected
swivels in the two end pieces through packed glands and these
end pieces receive the oil and steam or air pipes which supply
the fuel and atomizing agent.
The tendency at the present time seems to be somewhat in
the direction of doing without both air and steam as atomizing
agents and relying entirely on the pumped pressure of well
sieved and heated oil to effect the necessary atomization.
Mixed systems must long continue to be employed, burning
solid and liquid fuel in the same furnace.
Twenty years ago the calorific value of the world's oil pro-
duction was but one-twentieth of the heat value of coal.
To-day (1921) the ratio has risen to one-tenth, but it is still
a far cry to the day when coal will be passed in the race, if
indeed such a day can ever arrive.
The majority of fuel-burning plants must still be either of
sclid fuel or of mixed type, and the greater the number of
all- liquid plants which come into use the less oil will there be
for other consumers.
The Gregory Burner.
This burner (Fig. 82a) consists of a central oil passage
placed within a steam cone, the oil being regulated by a central
needle or spindle valve with hand wheel as shown, and the
steam by the usual supply valve. Air mixed with highly
heated furnace gas is drawn by the inductive action of the
steam into a chamber surrounding the atomizing nozzle, and
serves to gasify the already heated oil and greatly to aid and
render perfect its combustion.
265A LIQUID FUEL AND ITS APPARATUS
Suitable clearing plugs are provided. By this burner it
has been found possible to burn any inferior solid fuels by the
use of small quantities of oil without smoke, and otherwise
impracticable fuels may be employed with very considerable
resulting economy.
The heated gases, drawn from the furnace, thoroughly dry
and superheat the steam, the temperature of the mixed vapours
being moderated by admission of cold air by the inlet indi-
cated in the figure.
The burner shown is of locomotive type, but the system is
equally applicable to stationary boilers and may also be em-
ployed in furnaces with oil fuel alone.
One of its great advantages is the manner in which inferior
fuels may be enabled, by the use of a small quantity of oil,
to improve their combustion by the increment of furnace
temperature that may be brought about by the oil. This
is a valuable feature in view of the great amount of inferior
coal now to be found on the market. This was recognized by
M. Bertin of the French Navy many years ago, but the Gregory
burner enables such necessary temperatures to be more readily
attained.
Great stress is laid on the gasification of the oil by the hot
gas. Assuming 1 pound of gas drawn in at 2000 F. from the
furnace and a specific heat of 0-25 ; which according to Ber-
thelot's researches should be much under the truth for high-
temperature gas ; there will be 500 B.Th.U. added to the oil.
One pound of oil has a latent heat of vaporization probably
not over half that of w^ater, so that 1 pound of hot gas should
fully vaporize 1 pound of oil, and such hot gas would only be
a small fraction of the weight of the air necessary for com-
bustion.
The claims for this burner's good performance thus appear
to have a properly sound thermal basis. Probably some of
the good performance may be the result of the gasification
of the hot oil in an atmosphere giving little or no support to
combustion, so that the hydrogen is not abstracted too soon,
leaving the nascent carbon to assume the difficult state of a
gas carbon similar to the well-known retort carbon of the
gasworks.
26 5B
CHAPTER XIX
METALLURGY. THE HOVELER PROCESS
IT is outside the intended scope of this book to deal very
seriously with the metallurgical applications of liquid
fuel. The author dealt with this at some length in Liquid
Fuel and Its Combustion.
Since that book was written there has been perhaps fully
as much progress in the metallurgical application as in power
application.
If in a furnace, ore or metal is acted upon too close to the
point of initial combustion of the oil the flame will be power-
fully oxydizing and therefore inoperative for reducing work.
As shown in the above book, the oil must be burned in a separate
chamber, in advance of the working furnace.
This is accomplished in the " Hoveler " system by placing
the oil atomizer, actuated by compressed air at 15 pounds
pressure, behind a small conical retort lined with refractory
material. Ignition occurs as the atomized jet enters this cone,
the flame tapering outwards within the cone and coming out
by a circular orifice. This apparatus can be carried about on a
wheeled standard or slung in a chain and placed outside any
furnace it is desired to heat. The cylindrical bar of flame passes
through an opening of its own diameter a few inches and
will maintain the interior of a large rotary furnace, or of an air
furnace at a high temperature. By suitable regulation the
effect obtained can be oxydizing or reducing according to the
amount of air admitted. By this system very high efficiency
of the fuel is obtained, but as in all metallurgical processes
which involves high temperature work the effluent gases must
inevitably carry away heat proportionate to the temperature.
The atomizer of the Hoveler system (Fig. 65) receives the oil
via a in a central tube h, in which is a needle stem / that con-
verts the orifice into an annulus c. Compressed air comes via
b outside the conical end of this oil tube by the tube g and the
atomized jet is discharged into a cone i, through which atmo-
spheric air is induced to flow via d. The treble mixture issues
METALLURGY: THE HOVELER PROCESS 267
by a parallel opening d projecting through a larger opening e,
which can be made to supply a further amount of compressed
air if needed via c.
For a reducing flame the compressed air is supplied at only
10 pounds pressure, and in reducing ores or oxides small coal
may be mixed with the stuff to be reduced, its duty being to
supply carbon the more energetically to absorb the oxygen
of the heated material. The use of liquid fuel in metallurgical
work possesses all the advantages of convenience, cleanliness,
control and time saving which appertains to its use in steam
raising, and in metallurgy there is also a marked economy
in the percentage of reduction and improved product. Though
much dearer per ton than coal, liquid fuel gains very consider-
Fig. 65. HOVELER ATOMIZER.
ably by reason ot the amount of it that is not used, for, where a
heat must be maintained to the last the coal fire is left large
and active, but the oil flame is shut off at once. Oil gains by
reason of superior efficiency in the application of the heat pro-
duced.
The Aerated Fuel Process.
This process of the Gilbert and Barker Co. of New York
is simply a system of atomizing by compressed air, and is used
in all manner of industrial arts, the flame being used direct
in metal work, glass making, japanning, etc. The apparatus
includes an air compressor, oil pump and receiver, storage
tank and the burners and necessary pipes.
Compression is to 15 pounds per square inch, a pressure
below which it is stated that the fuel is not perfectly atomized.
268 LIQUID FUEL AND ITS APPARATUS
The oil pump is itself worked by the air, and serves to keep
a full receiver of about 30 gallons capacity (25 imperial gallons).
The receiver also contains compressed air which forces
the oil to the burner (Fig. 67), where it meets the air
coming direct from the compressor. Valves regulate the
proportions and the air pressure preserves even working con-
ditions, whether two or twenty burners are at work. It is
claimed that the combustion is really gaseous, clean and smoke-
less. The main supply is a buried tank outside the building
and away from the burners. The oil pump is automatically
regulated by a float, and all apparatus is below the burners,
so that no gravity flow can take place. The use of gravity is
held by some to be bad practice, and this view will bear argu-
ment in its favour. Low pressure air is condemned as leading
to imperfect atomization and large globules which burn
imperfectly and deposit carbon and injure the fire-brick.
From 60 to 120 gallons of oil are claimed to do the work of a
ton of coal.
The process is held to be much superior to any steam atomiz-
ing process for metallurgical work.
Low pressure air which throws oil upon the fire-brick uncon-
sumed, causes these to shell off and break, and smoke is made
also while carbon is deposited in the furnace.
Applied to metallurgy, to forge furnaces, crucible heating,
and other industrial work outside steam raising, the advantages
of oil fuel are not merely absence of dirt and dust, but there is
no loss of time through men waiting for fires to burn up. There
are no times of good or of bad fires, no uneven heat, but a full
flowing flame is maintained with an even continuous degree of
heat. Then the economy of oil is largely secured by increased
production and better work. Oil has the advantage over gas
fuel also, which, though equally good in the furnace, cannot be
produced without labour and dust and at a considerable
outlay in plant and apparatus.
The calorific capacity of various gases is as per following
table
Heat Units per
thousand cubic feet.
Natural gas 1,000,000
Air gas (gas machine) 20-candle power . . 815,500
Public illuminating gas, average .... 650,000
Water gas (from bituminous coal) . . . 377,000
Water and producer gas (mixed) .... 175,000
Producer gas 150,000
Blast furnace gas 100,000
Since a gallon of fuel oil (7 pounds) contains 151,000 heat
METALLURGY: THE HOVELER PROCESS 269
units, the following comparisons may be made. At three cents
a gallon (about l-8d. per English gallon), the equivalent heat
units in oil would be equal to
Dollars per
thousand cubic feet.
Natural gas at -1987
Air gas 20-candle power , -1620
Public illuminating gas, average .
Water gas (from bituminous coal)
Water and producer gas (mixed) .
Producer gas
Blast furnace gas
1291
0749
0347
0298
0200
At four cents a gallon (about 2-4cZ. per English gallon) the
equivalent heat units in oil would equal
Dollars per
thousand cubic feet.
Natural gas . at -2649
Air gas, 20-candle power , '2160
1722
0998
0463
0397
0265
Public illuminating gas, average .
Water gas (from bituminous coal)
Water and producer gas (mixed) .
Producer gas
Blast furnace gas
so that when oil will pay to use it may be installed at one-tenth
the cost of a gas plant and worked for a fraction of the cost in
upkeep and wages.
The Springfield System uses air as low as 18 or 24 ounces
pressure ; oil comes forward at forty pounds pressure. This
apparently contradicts the statements above, that low pressure
air is not satisfactory. Possibly an explanation is to be found
in the oil pressure which, as in the Korting system, should
itself do much towards atomizing the oil. Clearly the oil
must possess energy of itself or borrowed from compressed air
or steam.
Colloidal Fuel (1921).
During the past few years the colloidal state has been
attracting considerable attention, especially in the direction
of medicine.
The term colloidal properly applied appears to pertain to
a condition or atomic state assumed by substances under
certain conditions, such for example as the milky condition
269A LIQUID FUEL AND ITS APPARATUS
of calcium carbonate when thrown out of solution in water
when the excess molecule of C0 2 is removed by caustic
lime.
So-called colloidal fuel is that modern form produced when
finely divided carbonaceous matter is mixed with liquid
hydrocarbons so as to produce by practically a colloidal mix-
ture or one which will not separate out into a liquid and a
solid deposit. The continuity of the suspension appears to
be secured by the use of certain added products known as
" fixateurs."
Such a colloidal fuel may be used in an appropriate burner
and sprayed exactly as fuel oil.
It has been found practicable with suitable forms of soft
coals to add as much as 1-2 pounds of coal to 1-25 pounds of
oil, while at the same time the bulk is but little increased.
In the ordinary way a gallon of oil weighing 9J pounds per
gallon can be loaded up with coal until it weighs 12 pounds
per gallon. Obviously the storage capacity of a given bunker
space is very much increased, for example
B.Th.U. B.Th.U.
9-6 Ib. of oil at 17,500 = 166,250
2-6 Ib. of coal . . , 11,000 = 27-500
Total in same volume = 193,750
or, say, 17 per cent, additional calorific capacity per unit of
bunker space.
With special coal and the ratio 12-12-5 as above named
the results are as follows :
B.Th.U. B.Th.U.
1-25 Ib. of oil at 17,500 = 21,875
1-2 Ib. of coal 10,000 = 12,000
33,875
or equivalent to an increased unit calorific carrying power of
bunkers of 33J per cent. Thus much longer voyages can be
made without rebunkering.
The subject is too novel for further reference, but if present
indications hold good in respect of permanency of condition,
the subject of colloidal fuel must inevitably come into very
prominent view. Much is being done by Mr. Lewis, of the
METALLURGY: THE HOVELER PROCESS 269B
Fuels Laboratory, Dacre Street, Westminster, to whom I am
indebted for the foregoing figures, in respect of the chemical,
physical and mechanical examination of coals generally, and
many curious and valuable facts are coming to light.
CHAPTER XX
THE OIL ENGINE
OIL or liquid fuel engines may be divided into five classes :
(a) Those which use the lightest distillates of petro-
leum. They are known as petrol engines and they are strictly
only a form of gas engine, for the liquid they use is only admit-
ted to a vessel through which the engine draws its air supply.
The air is thus carburetted or petrolized, no liquid molecules
remaining, and ignition is electrical. It is not intended to treat
further of this class.
(b) The paraffine engine which employs the commoner grades
of lamp oil.
(c) Crude or heavy oil engines which are fed with heavy
oils.
(d) The Diesel engine, in which the fuel is sprayed into pure
air so highly compressed as to be at a red heat.
(e) The Griffin engine, which rejects incombustible bases
such as asphaltum.
A brief description of the latter four types will be sufficient
to show the application of liquid fuel to internal combustion
engines.
Class &. The Hornsby engine (Fig. 83) may be taken to illus-
trate this class. On the back cover of the cylinder is fixed a
bottle neck vaporizer, V, which is first heated by a lamp and is
afterwards kept hot by the explosions within it when the engine
has been set to work.
The back of the cylinder beyond the piston stroke forms,
with the vaporizer, the compression space. Air drawn into the
cylinder on the outstroke of the piston is compressed into the
vaporizer, into which oil is forced as spray by a small pump
at the moment of highest compression. The oil is vaporized
by the heat of the air, and the mixture ignites and expands
into the cylinder through the bottle neck. The oil pump works
always at full capacity, but a by-pass allows part of it to
escape back to the tank. This by-pass is controlled by the
governor. About 0-55 pint of oil (of -825 sp. gr.) per B.H.P.
27Q
THE OIL ENGINE 271
hour is consumed. The engine will use oil of 0-79 to 0-88 sp.
gr., and even heavier or crude oil may be used.
An engine of over 100 B.H.P. was run continuously night
and day for 500 hours =21 days. At the end of the time
there was practically no deposit in the vaporizer and the engine
would have run a much longer period without loss of power.
The oil used was the thickest Texas liquid fuel, and at the end
of the run the engine was working as well as at the beginning.
The particulars of the run are as below :
T?af^r>TT-p / no B.H.P. for refined oil.
1 100 B.H.P. for residual oil.
Total number of hours running 502
Fuel used . . . Texas, costing 3d. per gallon in tank wagons.
Specific gravity -933
Flash point (open test) 240 F.
Total amount of fuel used .... 15 tons 5 cwt. 1 qr. 17 Ib.
Amount used per hour 68*07
Average brake horse -power 100*8
Amount of fuel used per B.H.P. hour .... -578 pints.
Cost of fuel per B.H.P. hour -21675d.
Or for 100 B.H.P. Is. 9d. per hour.
Or 4-6 B.H.P. for Id. per hour.
The method of injection at the time of ignition probably
ensures as full a combustion of all the oil as is practicable, none
depositing before it has had a chance to burn. This helps to
prevent distillation to destruction or " cracking " which hap-
pens when oil is too highly heated. The lighter parts are driven
off as vapour and heavy residuals are left and may accumulate
in the vaporizers as solid carbon.
This need not occur with paraffine, which should never be
made so hot that it will not condense into the same liquid again.
The carbon difficulty has always attended the use of crude and
heavy oils, especially when these have an asphaltic base. The
base remains unconsumed, and when an engine stops and cools
it becomes glued up by the asphalte. It is better not to use
such oils in an engine. If such must be used it should, if
possible, be the practice to run the engine for a time, before
stopping, with paraffine in order to clear away any varnish-
like deposit before allowing the engine to stop and cool. See
class (e). But this is not necessary with ordinary crude oils,
such as are used in class (c). This class (c) is merely an exten-
sion of class (b) and includes the above Hornsby engine of which
the vaporizer is shown in Fig. 83 ; the Huston-Proctor engine, in
which a small vaporizing chamber is attached at the back of
the cylinder and receives the spray of fuel forced in through a
narrow orifice by which the oil is atomized. As far as
272 LIQUID FUEL AND ITS APPARATUS
possible the oil in this class of engine should be vaporized as
it enters and not allowed to fall liquid on too hot a surface, by
which it may be cracked or decomposed with formation of
solid carbon.
All kinds of crude oil and residual oils have been tried in the
83. HOBNSBY OIL ENGINE VAPOBIZEB.
Huston-Proctor engine, varying in sp. gr. from 0-86 to 0-96.
A special Italian residual oil with 15 to 25 per cent, of tar
was tried also, and in no case was there any gummy or sooty
deposit.
In this class of engine the oil sprays by its own heavy pressure.
Fuel consumptions are claimed as low as 0-45 Ib. per b.h.p.
THE OIL ENGINE
273
hour, but 0-5 Ib. should usually be assumed. In the Ruston
engine a small quantity of water is injected into the cylinder
at each suction stroke. In the Hornsby engine this water
injection is not used. The use of water has its advocates and
the reverse. In its favour are claimed that it is a safeguard
against overheating at full loads, that it prevents knocking
from over-hot valves or piston, and obviates risk of cylinder
scoring and seizing of pistons.
Class (d) : The Diesel engine occupies this class by itself.
Fig. 84. ENLARGED CROSS SECTION or VAPORIZER.
It depends for its working upon the compression of a charge
of pure air to so high a pressure some 35 atmospheres
that oil injected into this air will be ignited. Since the air
charge has a pressure of about 500 pounds per sq. in., the air by
which the fuel is sprayed into this charge is furnished by a pump
at about 800 Ib. pressure. The engine is best started by com-
pressed air, a store of which is maintained. The storage vessels
are sent out, ready charged, with the engine, and serve for
starting from the first, and the air pressure is carefully main-
tained so to avoid the inconvenience of hand pumping a fresh
store.
274 LIQUID FUEL AND ITS APPARATUS
The thermal efficiency of the Diesel engine is given by one
maker as 40-7 per cent, on the indicated horse power, and 31
per cent, on the brake horse power. The Author's own tests
fully corroborate these figures. The best steam engines give
similarly 22-0 per cent, and 20-5 per cent, with superheated
steam at 300C.= 572F. This of course does not include the
boiler. Producer gas engines give 20 to 26 per cent.
Many oil engines work on the Otto cycle, which is a four
stroke cycle, but in many Diesel engines, especially for marine
work, the engine drives an air scavenging pump and the exhaust
takes place by a ring of ports uncovered by the piston and the
waste gases are swept out by a scavenging of air, and the engine
is then run on the two-stroke cycle.
The use of liquid fuel in the Navy has naturally led up to
the employment of the oil engine, and the Diesel engine, by
reason of its economy, has become the accepted type. Its oil
consumption at full load is about 0-44 Ib. of oil per b.h.p. hour.
Assuming the oil to have a thermal capacity of 19,320 B.Th.U.
and the heat equivalent of one horse power to be 2,544
B.Th.U., an engine using 1 pound of oil per h.p. hour would
have an efficiency of 2,544 -f- 19,320 = 13-1 per cent. The
efficiency with any other rate of fuel consumption would be
this last number -; fuel consumption. Thus if the fuel con-
sumption were 0-4 Ib. per h.p. hour, the efficiency would be
32-0 per cent, and this may be attained in the Diesel engine.
The position already taken by the Diesel engine in marine
work is already good, but as in all four-stroke single acting
engines, the weight is great for the power developed, and the
tendency is to convert it into a two-stroke engine and also to
make it double-acting. This of course demands an exhaust
uncovered by the piston and a scavenging charge of air to
sweep out the exhaust gas, but these are details which may
pertain to all engines and do not apply to the question of the
fuel used by them, and need not here be further considered.
Class (d), the Griffin engine, of which Fig. 85 shows a section
of the vaporizer of a 9|" X 10|" X 4 cyl. engine, occupies this
class of heavy oil-using engines.
It is based on the claim that no engine can satisfactorily
use an oil with a heavy base, particularly an asphaltic base.
In it, therefore, is embodied an exhaust heated external
vaporizer. This is first heated by an air blown flame, and serves
to vaporize the first charge, and it is maintained at about 450F.
=232C., by the subsequent exhaust gases. The oil is distilled
but not cracked ; the heavier portions remain unaltered and are
run out of the vaporizer by a gravity pipe. The Author has
THE OIL ENGINE 275
seen such rejected portion placed on a cold iron plate, and it
became a hard dry varnish at once, as it would have done
inside the cold engine if allowed to get in.
The interior of the Griffin engine remains clear of all deposit
of carbon or coke or asphalte. There is always found some
very fine ash in petroleum, and this also is kept out of the
cylinder, where its presence would produce abrasion. The oil
is heated in the supply pipe to the vaporizer, as is also the air
for spraying it in. This facilitates the free flow of the oil, and
assists in fine atomization.
The vaporizer, Fig. 85, has an outer jacket marked lOfdia.
in this size, surrounding an inner annular chamber 7f " dia.,
which in turn encircles a central vaporizing chamber 5J" dia.,
into which the fuel is sprayed. The exhaust gases from the
cylinder traverse the annular chamber. Their temperature is
a maximum of 550E. = 288C., which becomes 450E. 232C.
in the annular chamber. Thus the fuel is vaporized, not gasi-
fied, a physical and not a chemical change. It is in fact merely
a fractional distillation which leaves the undesirable refuse to
be run out of the still as tar or asphalte. The vaporizer is only
at atmospheric pressure ; it is never exposed to great tempera-
ture.
All the air required in the cylinder does not pass through the
vaporizer. Enough passes that way to carry in the charge of
oil vapour ; the remainder is admitted by a separate air valve.
Incidentally this engine is started by a momentum device, the
fly-wheel having a friction clutch grip on the shaft. A boy can
gradually get up the fly-wheel of a 40 h.p. engine to a sufficient
speed ; it is then gripped to the shaft and finds the starting
energy.
Ignition is by a refractory body in a small and isolated cavity
communicating with the combustion chamber. A timing valve
may be supplied if required.
The oil and the compressed air by which it is sprayed into
the heated vaporizer, are both heated so as to render spraying
more perfect. The temperature of the vaporizer is less than
that which would gasify the oil, and the tar is left behind in
place of going forward to the cylinder and doing harm.
The incombustible ash sticks to the side of the vaporizer and
can be removed by a wire brush when the engine is stopped.
The spray injector, which also serves as the heating blow-
lamp, has an adjustable inner nozzle through which comes air
at 20 Ib. pressure. Oil flows in through an annular chamber
round this inner nozzle, and is pulverized by the air and
vaporized by the hot chamber.
276 LIQUID FUEL AND ITS APPARATUS
Both oil and air are supplied at 20 Ib. pressure, the oil coming
from a closed tank to which the air pressure pump has a con-
nexion, and the supply of oil is regulated by a governor which
controls the air at the atomizer. There is no change in the
richness of the mixture supplied but only in its volume, the
air and the oil being simultaneously varied.
THE OIL ENGINE 277
The engine can be started if desirable with light oils, as
petrol and electrical ignition, the heavy oil being turned on
when the vaporizer has become hot. This avoids the use
of the blow-lamp heater in the locality of inflammable
vapours.
It should be added that for each 1,000 feet of elevation above
sea level an engine ought to be about 3 per cent, larger owing to
the rarefied air. For a number of engines it might be found
cheaper to pump air to them at a pressure of one absolute
atmosphere, so that with this compound system no increase of
engine size need be made. This applies to all oil or gas engines
when worked at considerable heights above sea level.
It is external to the intention of this book to afford
more than an outline of the general systems of using liquid
fuel in the internal combustion engine, its general mechan-
ism, etc.
For details of the legion of different engines, their valve sys-
tems, sprays, vaporizers, the Author would refer his readers to
the books of Mr. Dugald Clerk, the late Bryan Donkin and the
catalogues of makers.
As the liquid fuel engine is improved, and its operation made
more and more certain, so will its superior thermal efficiency
bring it into wider use. There appears to be no immediate
prospect of a direct oil fuel turbine engine, and all existing
engines are of the reciprocating type, which steam turbine makers
have endeavoured with so much success to put out of use for
steam using. But the turbine runs too fast to suit the propeller
and this is all in favour of the reciprocating oil engine. At
present, even the Diesel engine must be run on selected fuel as
regards freedom from asphalte, etc. Such oils with an asphaltic
base which might be rejected to the extent of 15 per cent, by the
Griffin engine would be unsuitable at sea even if their unde-
sirable elements were rejected by the engine, for no shipowner
wants to carry the excess of fuel that this implies. On land,
therefore, any fuel can be used in some engines ; at sea, liquid
fuel must be selected, except for short journeys. The ability
to burn any fuel under boilers in high temperature refrac-
tory furnaces will do much to preserve steam power against
the inroads of the more highly efficient internal combustion
engine. The near future will see many oil engines in marine
work.
It will be noted that essentially the method of using oil
in the internal combustion engine is by spraying or atomizing
the oil into the air with which it is to burn, or by spraying it
into a vaporizer in which it is evaporated, and whence it passes
278 LIQUID FUEL AND ITS APPARATUS
into the cylinder as a vapour. Petrol vaporizes at ordinary
atmospheric temperature. Heavy oils must have the high
temperature vaporizer of the Griffin engine, or be directly
ignited and burned in the highly heated chambers of other
types of engine or burned in the " red hot " air of the Diesel
high compression engine.
Part III
TABLES
TABLES
281
TABLE I. Composition of Crude Oils.
Name.
C.
H.
0.
Sp. G.
Per deg. C.
Coeff. of
Expansion.
B.Th.U.
Cal.
Capacity.
Heavy Virginia
Ohio . .
Pa.. . .
Gas coal oil
E. Galician
W. Galician . .
Java ....
Caucasian
Rangoon
83-5
84-2
84-9
82
82-2
85-3
87-1
85-3
83-8
13-3
13-1
13-7
7-6
12-1
12-6
12-0
11-6
12-7
3-2
2-7
1-4
10-4
5-7
2-1
0-9
5-1
3-5
873
887
886
1-044
-870
885
-923
-9405
875
00072
000748
000721
00744?
000813
000775
000764
000696
000774
10,180
10,399
10,672
8,916
10,005
10,231
10,831
TABLE II. Calorific Capacity of Liquid Fuel Oils.
Locality.
Fuel
Sp. G.
0C.
C.
H.
0.
Calorific
Capacity.
Actual
Calories
Calcula-
ted Cal.
Russian .
Caucasus .
American
Scotcji
Pet. refuse .
Astatki . .
Heavy crude
Solid residuum
B.F. Oil . .
928
900
938
920
87-10
84-94
86-60
97-855
83-64
11-7
13-96
12-30
0-489
10-59
1-2
1-2
1-1
1-196
9-458
10,340
11,800
8,057
10,328
11,018
11,626
11,200
TABLE III. Coefficient of Expansion of Crude Oils.
Sp. G.x 1,000.
Coefficient of
Expansion of Crude
Oil x 1,000,000
Dr. Engler.
Pennsylvania
816
840
Canada
828
843
Alsace
829
843
Virginia
841
839
Alsace
Wallachia
861
862
858
808
E. Galicia
870
813
Rangoon
875
774
Caucasus
882
817
W. Galicia
885
775
Ohio
887
748
Baku
899
784
Hanover (Odesse)
892
772
Pechelbronn
892
792
Wallachia
Hanover (Oberg)
901
944
748
662
Hanover (\Viesse)
955
647
Heavy viscous oils 0-0007 to -00072 between 20 and 78C. =68
172-4F. containing paraffin and solid below 20 =0-0075 to -00081.
to
282 LIQUID FUEL AND ITS APPARATUS
TABLE V. THE PROPERTIES OF
Required to burn
Nominal tern
one unit.
combu
Name.
Sym-
bol.
Den-
sity
H = l
Mole-
cular
Weight
Lb.
per
cubic
feet.
Cubic
ft.
per
Ib.
Grams
per
Litre.
Litres
per
Gram.
Weight.
Volume.
Air.
Air. Ox y
Air.
Oxy
F.
C.
gen.
gen.
Air
(0 23 )
\ N 7B V
14-44
08073
12-385
1-29318
773
Carbon, C
Amorphous .
) 76 i
U, J
-{
to CO I
to C0 2 )
2673-5
4938
1485
2753
Vapour . .
12
06696
14-930
1-0727
932
9-54
2-00
6955
3846
Carbon Dioxide .
C0 2
22
44
12344
8-147
967
508
Carbonic Oxide
CO
14
28
07817
12-80
1-2515
800
2-484
571
2-3S1
500
3494
1923
(
Wate:
Hydrogen .
H 2
1
2
00559
178-83
08981
11-16
34-785
8-000
2-39
500
4813
2674
Oxygen . . .
2
16
32
08926
11-203
1-4298
699
_
Nitrogen . . .
N,
14
28
07845
12-763
1-25616
796
Steam ....
H 2
9
18
05022
19-912
8047
1242
Acetylene . . .
C 2 H 2
13
26
07267
13-456
1-190
840
13-378
3-077
11-93
2-500
6120
3400
Benzine.
C 6 H 6
39
78
208
4-808
3-333
303
13-378
3-077
35-80
7-500
5022
2790
|
Ethylene . . .
C 2 H 4
14
28
07814
12-797
1-2519
799
14-903 | 3-428
14-30
3-000 5400
3000
Ethane ....
C 2 H 6
15
30
08565
11-950
1-3415
746
16-484 3-733
16-70
3-500 4354
2419
Methane . . .
CH 4
8
16
04466
22-391
7155
1-397
17-392(4-000
9-54
2-000 4036
2245
Ethyl ....
C 2 H 6
23
46
12857
7-775
2-061
287
9-074
2-037
14-30
3-000
4630
2573
Methyl ....
CH 4 O
16
32
08926
11-203
1-4208
699
6-521
1-500
7-15
1-500
4183
2325
Cyanogen . . .
C 2 N 2
26
52
1453
6-88
2-338
427
5-348
1-23
9-54
2-000 6099
3388
Glycerine .
C 3 H 8 3
92
18-148
4-174
16-70
3-500 4000
2222
Blast Furnace Gas
/ 1 r\f\
.OO ^
FCO] 27 N 65 (C0 2 ) 6
H 2 . . . .
14 +
079
12-65
1-2515
800
j *1UU
\-721
2.2, }
166 J
82
164 2160
'
1200
ProducerGas [C0] 25
(Sundry) r5 -[C0 2 ] 2 . 5
14 +
079
12-65
1-2515
800
(99
\-721
21 }
166 j
(3440
I 2160
1910)
1200 J
[CH 4 ] 2 , N 69 . .
Water Gas |CO] 76 ,
[CH 4 1 2 , [Sundry] 7 - 5
(C0 2 ) 10 N 2 . 5 . .
8 +
045
22-5
726
1-40
3-878
788
4850
2700
Coal Gas, H 8 [CH 4 ] 57
[C0] 15 N 4) (Sun-
dry)^ . . .
4-7
032
31-6
516
1-975
13-89
2-81
6-16
1-23 4500
2500
Natural Gas(CH 4 ) 90)
N 6 , Sundry 4 . .
8
-045
22-5
1-726
1-40
15-00
3-06
4200
2333
NOTE. Gases expand by heat to the extent of ^ of their bulk at 0C. for each degree Centigrade, or jgj^
The specific heat of gases varies with the temp3rature, being greater for higher temperatures. At the
Lechatelier therefore gives a formula for specific he.it C p = 6-5 +aT, where T is the absolute temperature
This has an important bearing on the theory of the gas engine.
TABLES
283
GASES (KEMPE'S YEAR BOOK).
perature of
Heat generated by combustion of one
Heat of
Specific Heat.
stion.
formation at
15C. per
Oxygen.
Lb.
Cub. ft.
Gram.
Litre.
Molecule.
Molecule.
Water =1.
F o
C
B.Th.U.
B.Th.U.
Cal.
Cal.
Cal.
Cal.
Liquid.
Constant.
^
Pressure
Volume.
2375
1686
7725
4292
4415-9
_
2-4533
29-44
2-84 1 \
2415
18440
10226
14647
8-1375
97-65
3-343 J
25752
14290
20461
1370-5
11-3675
12-193
136-41
f 3S-76 2 \
\ 42-13 ;
285
68-20* )
_
94-313
216-9
171
97-65 a j
perun
12892
.of C.=
7144
10232 )
4383 |
( 799-3
\ 342-5
f 5-684
t 2-436
f 7-105)
\ 3-047 j"
68-2
i 26-13 x
[ 29-4 2 J
245
'173
Vapo
12108
ur) (
6727 |
52290
at 32F.
62100
(293
\347
f 29-15
\ 34-50
f 2-612
\ 3-091
( 58-3 gas \
\ 69-0 liq. L
1 70-4 solid j
-
3-410
234146
Water Liquid.
217
15481
244
173
l
Solid = 70-4 \
1 1-0 liq. \
-
Liq. =69-0 \
Gas =58-3J
perH 2
-504
( Solid j
479
370
20340
11300
21856
1624
12-142
14-46
315-7
58-1
373
16830
9350 |
18094 \
17930 j
3764
J 10-052 )
\ 9-960 J
33-496
f 784-1 gas
I 776-9 liq.
(1-8 sol. \
- 4-1 liq.
(11 -3 gas)
43602
3754
350
16886
9381
21927
1744
12-182
15-250
341-1
14-8
404
332
14848
8249
22338
1912
12-410
16-641
372-3
23-3
14348
7971
24017
1073
13-343
, 9-547
213-5
18-9
593
468
125S3
6690
12744
1639-1
7-080
14-54
325-7
f 59-8 gas )
\ 69-9 liq. }
f -60 liq. I
I -50 gas J
451
320
10216
5675
9596
856-5
5-331
7-627
170-6
( 53-3 gas )
\ 61-7 liq. >
f -66 liq. )
I -46 gas )
18222
10215
9086
1320-6
5-048
12-02
262-5
f 73-9 gas I
\ 68-5 liq. }
8078
4488
7770
4-317
397-2
f 161-7 liq.)
\ 165-6 sol. J
4500
2500 |
1223 to
1237
96-7}
97-8}
700
900
4590
2500 \
1265 to )
100 to
f -773 to
i -9674 to
2530 /
200
1 1-370
1 1-713
f
4230 to
330 to
( 2-35 to
3-00 to )
__
\
5458
700
\3-03
6-33 J
21400
685
11-9
6-099
24444
1100
13-58
10-0
1 From Graphite. 2 From Amorphous Carbon. 3 From Diamond. 4 From Carbonic Oxide,
of their bulk at 32F. for each degree F..
absolute zero the values of the molecular heat of all gases seems to converge at 6-5 for constant pressure values.
dpL and a is a co-efficient greater according to the complexity of the molecule. For values of a see table,
(T= Temperature Centigrade.)
284 LIQUID FUEL AND ITS APPARATUS
TABLE IV. Calorific Power of Crude Oil.
Sp. Gr.
Cal. Capacity.
W. Virginia
873
10190 cals
Oil Creek, Pa
816
9963
923
10831
Baku
E. Galicia
W. Galicia
884
870
885
786
11460
10005
10231
10121
Schwabweiler (Alsace) ....
861
10458
TABLE VI. Temperature.
C.
F.
Red heat in daylight
Iron red in dark . .
577
400
1070
752
Bessemer furnace
2205
4000
Common fire
Copper melts .
Lead
595
1232
316
1100
2160
600
Tin
215
420
Grey cast-iron melts
White
Carbon vaporizes . . .
1100
1050
3600
2012
1922
6512
TABLE VII. Specific Heats of Gases.
Const. Vol.
Const. Pressure.
Air .......
168
2375
1548
217
173
244
2-4146
3-410
173
245
171
216
468
593
Olefiant gas C 2 H4 . .
332
404
Steam H^O
370
479
Blast furnace sas
163
228
Steam boiler furnace gas.
171
240
. ]
298
. . . . ]
138
Steel
Brick
. . . . ]
.f
17
$41
TABLES
285
TABLE VIII. Equivalents.
Cal ........... 3-968 B.Th.U.
B.Th.U ..... ..... 0-252 CaJ.
C ............ fF.
F ............ |C.
C ............ tR.
R ............ | C.
kilog ........... 2-204
pound ......... 0-453 k.
1 B.Th.U .......... 772 ft. pounds (old).
......... 778 (new)
1 calorie ......... 423-55 k.m. (old).
......... 426-84 (new).
772 ft. p. per 1F ....... 1389-6 ft. p. per 1C.
778
423-55 k.m.
426-84 k.m.
1400-4
3063-54 ft. Ib.
3087-3 ft. Ib.
107-78 k.m.
7-231 ft. Ib.
2 Ib. per yard nearly.
B.Th.U
k.m
k. per linear m
B.Th.U. per foot 3 ...... 9 Cal. per m. 3
......... . 32-2 ft. per sec. 2
g ...... ..... 9-8117 m. per sec. 2
1 B.Th.U. per ft. 2 ...... 2-713 cal. per m. 2
1 Ib ....... 0-556 cal. per kilo.
1 kilo, per cm. 2 ..... . . 14-2 Ib. per sq. inch.
1 Ib. per sq. inch ...... 0-0703 kilo, per cm. 2
1 metre-kilo ......... 7-231 ft. pounds.
1 ft. pound ........ 0-138 metre-kilo.
TABLE IX. Properties of Carbon Calorifically,
Calories per
British
Thermal Units.
Temperature
of Com-
bustion.
Mole-
cule.
Litre.
Gram.
Per
Cubic Ft.
Per
Pound
In Air.
Amorphous to CO .
29-44
2-453
4416
1485
2705
CO 2 .
97-65
8-1375
14647
2753
4988
Vapour to CO . .
68-20
6-096
5-864
685-25
10231
3540
6373
C0 2 . .
136-41
12-193
11-3675
1370-50
20461
2846
6955
CO=2^1b. to CO 2 .
68-20
3-046
5-684
342-50
10232
1923
3494
CO = lib. toCO 2 .
29-23
3-048
2-436
342-50
4384
1923 3494
Hydrogen to H 2 O gas
58-30
2-612
29-15
293-00
52290 2513|4554
,, H 2 O water
69-00
3-091
34-50
347-00
62100 2974 5385
The important figures for practice are in black type.
286 LIQUID FUEL AND ITS APPARATUS
TABLE X.
TENSION (f.) OF AQUEOUS VAPOUR IN MM. OF MERCURY PER DEGREE
CENTIGRADE (T. ) AND GRAMS (g.) PER CUBIC METRE OF SATURATED AIR.
T.
g.
f.
T.
g'
f.
rpo
g.
f.
4-5
11
10-0
9-7
22
19-3
19-6
1
4-9
12
10-6
10-4
23
20-4
20-9
2
5-2
13
11-3
11-1
24
21-5
22-2
3
5-6
14
12-0
11-9
25
22-9
23-5
4
6-0
15
12-8
12-7
26
24-2
25-0
5
6-8
6-5
16
13-6
13-5
27
25-6
26-5
6
7-3
6-9
17
14-5
14-4
28
27-0
28-1
7
7-7
7-4
18
15-1
15-3
29
28-6
29-8
8
8-1
8-0
19
16-2
16-3
30
29-2
31-6
9
8-8
8-5
20
17-2
17-4
10
9-4
9-1
21
18-2
18-5
TABLE XI.
BELATIVE VALUE OF COAL AND OIL,
FUEL ACCOUNT ALONE CONSIDERED.
BELATIVE VALUE OF COAL AND OIL, ALL
ASCERTAINED ECONOMIES CONSIDERED.
,r Barrel at Coal per Ton at Coal per Ton at
0-20
$0-74
$0-65
0-30
1-12
0-98
0-40
1-49
1-30
0-50
1-86
1-63
0-60
2-24
1-96
0-70
2-61
2-28
0-80
2-98
2-61
0-90
3-35
2-93
1-00
3-73
3-26
10
4-10
3-59
20
4-47
3-91
30
4-85
4-24
40
5-22
4-56
50
5-59
4-89
60
5-97
5-22
70
6-34
5-54
80
6-71
5-87
1-90
7-08
6-19
2-00
7-45
6-52
1 dollar =48 pence,
approximately.
TABLE
XII. Russian and Pennsylvanian Oils.
Penn-
Russian.
sylvanian.
Light.
Heavy.
Refuse.
Per cent.
Per cent.
Per cent.
Per cent.
Carbon .
Hydrogen
84-9
13-7
86-3
13-6
86-6
12-3
87-1
11-7
Oxvfifsn
1-4
0-1
!!
1-2
Sp. Gr. at 32F
B.Th. Units
100-00
0-886
19,210
100-00
0-884
22,628
100-00
0-938
19,440
100-00
0-928
19,260
Evaporation at 8 atmospheres .
16-2
17-4
16-4
16-2
TABLES
287
TABLE XIII. Petroleum Refuse.
Specific Gravity and Weight per cubic foot, at various temperatures.
Water = 1-0000 specific gravity, at 17 Cent. =63^ Fahr.
Temperature.
Specific
Gravity.
Weight in Ib.
per cubic foot.
Centigrade.
Reaumur.
Fahrenheit.
0-0
32-0
0-9110
56-61
1
0-8
33-8
0-9103
56-55
2
3
1-6
2-4
35-6
37-4
0-9097
0-9091
I 56-50
4
3-2
39-2
0-9085
56-42
5
6
4-0
4-8
41-0
42-8
0-9078
0-9072
56-36
7
5-6
44-6
0-9066
\
8
6-4
46-4
0-9060
y 56-30 .
9
7-2
48-2
0-9053
56-20
10
11
8-0
8-8
50-0
51-8
0-9047
0-9041
56-14
12
9-6
53-6
0-9034
56-11
13
14
10-4
11-2
55-4
57-2
0-9028
0-9022
1 56-05
15
12-0
59-0
0-9016
55-99
16
12-8
60-8
0-9009
I *t^'<)2,
17
13-6
62-6
0-9003
V * ) ) . '_
18
14-4
64-4
0-8997
KK.QA
19
15-2
66-2
0-8991
[ OO o*t
20
16-0
68-0
0-8984
55-81
21
22
16-8
17-6
69-8
71-6
0-8978
0-8972
1 55-74
23
18-4
73-4
0-8965
55-68
24
25
19-2
20-0
75-2
77-0
0-8959
0-8953
I 55-62
26
27
20-8
21-6
78-8
80-6
0-8947
0-8940
I 55-55
28
22-4
82-4
0-8934
55-48
29
30
23-2
24-0
84-2
86-0
0-8928
0-8922
I 55-43
31
24-8
87-8
0-8915
55-37
32
33
25-6
26-4
89-6
91-4
0-8909
0-8903
j 55-30
34
35
27-2
28-0
93-2
95-0
0-8896
0-8890
55-24
288 LIQUID FUEL AND ITS APPARATUS
TABLE XIV. Conversion Table for Degrees Baume.
Degrees
Baume.
Degrees
Sp. Gr.
Lb. in 1 gal.
(American).
Degrees
Baume 1 .
Degrees
Sp. Gr.
Lb. in 1 gal.
(American).
10
1-0000
8-33
43
8092
6-74
11
9929
8-27
44
8045
6-70
12
9859
8-21
45
8000
6-66
13
9790
8-16
46
7954
6-63
14
8722
8-10
47
7909
6-59
15
9655
8-04
48
7865
6-55
16
9589
7-99
49
7821
6-52
17
9523
7-93
50
7777
6-48
18
9459
7-88
51
7734
6-44
19
9395
7-83
52
7692
6-41
20
9333
7-78
53
7650
6-37
21
9271
7-72
54
7608
6-34
22
9210
7-67
55
7567
6-30
23
9150
7-62
56
7526
6-27
24
9090
7-57
57
7486
6-24
25
9032
7-53
58
7446
6-20
26
8974
7-48
59
7407
6-17
27
8917
7-43
60
7368
6-14
28
8860
7-38
61
7329
6-11
29
8805
7-34
62
7290
6-07
30
8750
7-29
63
7253
6-04
31
8695
7-24
64
7216
6-01
32
8641
7-20
65
7179
5-98
33
8588
7-15
66
7142
5-95
34
8536
7-11
67
7106
5-92
35
8484
7-07
68
7070
5-89
36
8433
7-03
69
7035
5-86
37
8383
6-98
70
7000
5-83
38
8333
6-94
75
6829
5-69
39
8284
6-90
80
6666
5-55
40
8235
6-86
85
6511
5-42
41
8187
6-82
90
6363
5-30
42
8139
6-78
95
6222
5-18
The Sp. Gr. x 10 = weight in pounds per imperial gallon.
TABLE XV. Of the Heat of Combustion and Air consumed by various
Fuels.
Fuel.
Oxygen
per pound
of fuel.
Air per pound of
fuel.
Total heat
per Ib. of
fuel.
Evapora-
tion from
and at
212F.
Hydrogen .
Carbon to COa
Average Coal .
Coke . . .
Petroleum .
Ib.
8-0
2-66
2-45
2-49
3-29
Ib.
34-8
11-6
10-7
10-81
14-33
Cubic ft.
457
152
140
142
188
B.Th.U.
62,100
14,647
14,700
13,548
20,411
Ib.
62-4
15-0
15-22
14-02
21-13
TABLES
289
TABLE XVI. Theoretical Flame Temperatures.
In Air.
Centigrade.
Fahrenheit.
C to CO
C to CO 2
CO to CO 2 ...
1485
2753
1923
2705
4988
3494
Hydrogen
Marsh gas, CH 4
Olefiant gas C 2 H 4
2513
2245
3000
4554
4036
5400
Acetylene, C2H2
3400
6120
Benzine CHg
2790
5022
Producer gas
1200
2160
Coal gas
2700
2400
4860
4320
Naphthalene
2730
4914
Wood
2280
4104
Lignite (dry) .
1200
2160
Coal (bituminous).
1500
2700
TABLE XVII. Weight and Volume of Gases.
Weight.
Volume.
Per cubic
Per cubic
Per kilogram
Per pound
metre in
foot in
in cubic
in cubic
kilograms.
pounds.
metres.
feet.
Air
1-29318
0-08073
0-773
12-385
Nitrogen ....
1-25616
0-07845
0-796
12-763
Oxygen
1-4298
0-08926
0-699
11-203
Hydrogen ....
0-08961
0-00559
11-160
178-83
Carbonic acid, CO 2
1-9666
0-12344
0-508
8-147
Carbonic oxide, CO .
1-2515
0-07817
0-800
12-800
Carbon vapour, C .
1-0727
0-06696
0-932
14-930
Aqueous vapour, H 2 O .
0-8047
0-05022
1-242
19-912
Ethylene, C 2 H 4
1-2519
0-07814
0-799
12-797
Methane, CH 4 .
0-7155
0-04466
1-397
22-391
Acetylene, C 2 H 2
1-1900
0-07428
0-840
13-456
Benzine, C fi H 6 .
3-3333
0-208
0-303
4-808
Ethane, C 2 H 6 . . .
1-3415
0-08565
0-746
11-950
290 LIQUID FUEL AND ITS APPARATUS
tiq
C5 O5 FH O
CD U5 00 O
CD FH FH CO
O5 ^ CO ^
00 CM CM
CO
O5 -*l 00 O
CD CO 00 O
CO OO FH O
05 ^ 05 00
CO Th FH CD
<N
1 1
Th IO
CO FH
CD CO O5 l> O5 O5
00 00 t> FH FH FH
o o
05 05
O
lO
00 O5 CO O
FH 6 o ib
o oo
OO O
05 05
t- CO
<M CM 00 O
CO CO O5 IT**
O5 O5 t^ FH
O
05
o FH FH
.^
30 O O
5>
o
sO .
30000
>CMFHFHFH
o o
Ttf CO
^jj hj
+ +
O O
, (M
_ O5 O5 OO OO O5
M<N CO CO O CO
FH CO FH
6cD CO t^ O O
v^CO CO O Cp cp
CO CM i"H O5 IO
(M CO CD CO O
CO FH FH FH OO
8 5
.!> CO FH O O OO
Oco CO C^ O O CM
gcD CO 10 Cp cp ^
CM FH O CO -^ CO
? :.,.tf 9
. SL ^ s?
g
w,9
g
68
1
-tuoo
43' CO CD O5 T* CO CO
^OO CO l>- O5 CO FH
Q O5 O5 CM CO !> FH
CM CM FH t- CO >0
_ CO O5 CO <*! CO
3O5 rH CD O5 TH
^ CO CO O5 * r-l
<*-i O5 O5 IT*- O5 rj<
w w
-; O5 O5 GO CO O5
^ IO l> Th l> CO
CM CO CO IO CO
FH CO FH
TH l> Tj< TJH (N
^05 05 CO CO 05
SlO t- Th l> CO
CD CO O Cp cp
6 CO ^
.t- CO FH O O CO
>CO CO t^-O O CM
cp cp o cp cp *
CO CM FH 05 10 Th
O
00 <N
CM CM 00 CM CD 00
FH i i CM FH CM
'o ' M
-0
ggs^l
ooo W
H
TABLES
291
I
i
1
S
&
S
2
ss
g g 3
. 00 O5 CO pH
t^- CO t^- t^
00 O5 IO CO
Tt< l> OO O
(N O O
<N <M <N
. CO t- 00 (M
5 CO (M CO CO
t> O i- QO
w
o >-S
11?
PH
CO 1>-
<M PH
O5 CO CO PH O
o
00
< c t-
00 CO 00 CO
1 co -<* co co o
O CO 00 CO <M CO
^Qp CO Oi Oi CO
02 o o o o I-H
292 LIQUID FUEL AND ITS APPARATUS
TABLE XXI. Ignition Point of Gases (Mayer and Munoh\
Marsh gas, CH 4 *667C.
Ethane, C 2 H 4 616
Propane, C 3 H 8 547
Acetylene, C 2 H 2 580
Propylene, C 3 H 6 504
TABLE XXII.
Kilos per square metre x '2048 =pounds per square foot.
Pounds per square foot x 4-884= kilos, per square metre.
Kilos, per square cm. x 14-223 = pounds per square inch.
Pounds per square inch X -0703 = kilos, per square cm.
Evaporation from 16C. at 12 kilos, x 0-8222 = evaporation from and
at 100C. = 212F.
Evaporation from and at 100C. = 212F. x 1-216 = evaporation from
16C. = 61F. at 12 kilos.
Metres x 3-281 = feet.
Square metres x 10-764 = square feet.
Feet x 0-3048 = metres.
Square feet X 0-9308 = square metres.
Gallons X 4-546 = litres.
Litres X 0-21998 = gallons.
Cubic inches X 16-386 = cubic cm.
Cubic cm. x 0-061027 = cubic inches.
Gallons (Imp.) x 1-2012 = American gallons.
American gallons X 0-83226 = English Imp. gallons.
American gallons x 3-784 = litres.
Litres x 0-2642= American gallons.
Inches water gauge x 25-4 = millimetres water gauge.
Imp. gallons x 0-1606 = cubic feet.
Cubic feet x 6-288 = gallons.
Kilos per metre x 2-015 = pounds per yard.
Pounds per yard x 0-4962 = kilos, per metre.
Calories per M. 3 x 0-1121 = B.Th.U. per ft. 3
B.Th.U. per ft. 3 x 8-92 = cal. per M. 3
Calories per M. 2 x 0-3686 = B.Th.U. per ft.*
B.Th.U. per ft.* x 2-713 = cal. per Metres.
TABLES
293
TABLE XXIII. To determine Temperature by Fusion of Metals.
Substance.
Temp.
Fahr.
Substance.
Temp.
Fahr.
Substance.
Temp.
Fahr.
Spermaceti .
Wax- white .
Sulphur .
Tin ...
Bismuth
Copper .
120
154
239
448
512
2,003
Lead . .
Zinc
Antimony.
Aluminium
Brass .
619
754
815
1,180
1,742
Silver, pure
Gold coin .
Iron, cast .
Steel . .
Wrought iron
1,851
2,128
2,074
2,550
2,911
TABLE XXIV. Volume and Weight of Dry Air at Different Temperatures
under a Constant Atmospheric Pressure of 29-92 in. of Mercury,
the Volume at 32 deg. Fahr. being 1.
Temperature.
Degrees
Fahrenheit.
Volume.
Weight of
a Cubic Foot
inlb.
Temperature .
Degrees
Fahrenheit.
Volume.
Weight of
a Cubic Foot
inlb.
935
0864
212
1-367
0591
12
960
0842
230
1-404
0575
22
980
0824
250
1-444
0559
32
1-000
0807
275
1-495
0540
42
1-020
0791
300
1-546
0522
52
1-041
0776
325
1-597
0506
62
1-061
0761
350
1-648
0490
72
1-082
0747
375
1-689
0477
82
1-102
0733
400
1-750
0461
92
1-122
0720
450
1-852
0436
102
1-143
0707
500
1-954
0413
112
1-163
0694
550
2-056
0385
122
1-184
0682
600
2-150
0376
132
204
0671
650
2-260
0357
142
224
0660
700
2-362
0338
152
245
0649
750
2-465
0328
162
265
0638
800
2-566
0315
172
285
0628
850
2-668
0303
182
306
0618
900
2-770
0292
192
1-326
0609
950
2-871
0281
202
1-347
0600
1000
2-974
0268
294 LIQUID FUEL AND ITS APPARATUS
TABLE XXV. Table showing Number of British Thermal Units con-
tained in one pound of pure Water at varying temperatures and
densities, and pounds per gallon.
Density
Number
Density
Number
Tem-
pera-
ture.
or
Weight
of
of
Thermal
Units
Pounds
Weight
Tem-
pera-
ture.
or
Weight
of
of
Thermal
Units
Pounds
Weight
Deg.
Fahr.
1 Cubic
Foot.
in 1
pound of
per
Gallon.
Deg.
Fahr.
1 Cubic
Foot.
in 1
pound of
per
Gallon.
Pounds.
Water.
Pounds.
Water.
1
2
3
4
1
2
3
4
*32
62-418
32-000
10-0101
135
61-472
135-217
9-859
35
62-4212
35-000
10-0102
140
61-381
140-245
9-844
t39-l
62-425
39-001
10-0112
145
61-291
145-275
9-829
40
62-425
40-001
10-0112
150
61-201
150-305
9-815
45
62-422
45-002
10-0103
155
61-096
155-339
9-799
50
62-409
50-003
10-0087
160
60-991
160-374
9-781
55
62-394
55-006
10-0063
165
60-843
165-413
9-757
60
62-372
60-009
10-0053
170
60-783
170-453
9-748
65
62-344
65-014
9-9982
175
60-665
175-497
9-728
70
62-313
70-020
9-9933
180
60-548
180-542
9-711
75
62-275
75-027
9-9871
185
60-430
185-591
9-691
80
62-232
80-036
9-980
190
60-314
190-643
9-672
85
62-182
85-045
9-972
195
60-198
195-697
9-654
90
62-133
90-055
9-964
200
60-081
200-753
9-635
95
62-074
95-067
9-955
205
59-93
205-813
9-611
100
62-022
100-080
9-947
210
59-82
210-874
9-594
105
61-960
105-095
9-937
J212
59-76
212-882
9-565
110
61-868
110-110
9-922
230
59-36
231-153
9-520
115
61-807
115-129
9-913
250
58-75
251-487
9-422
120
61-715
120-149
9-897
270
58-18
271-878
125
61-654
125-169
9-887
290
57-59
292-329
130
61-563
130-192
9-873
* 32F. = Freezing point of water.
f 39'1F. = The temperature at which water is at its greatest density.
% 212F. = Boiling point of water.
A British Thermal Unit (B.Th.U.) = that quantity of heat that is required to
raise one pound of water through one degree Fahr. at or near 39'1F.
TABLE XXVI. Saturated Steam.
Saturated Steam is dry steam at the maximum pressure and density,
due to its temperature not superheated. It is attained when all
latent heat required for the steam has been taken up this is called
" Saturation Point." A vapour not near the saturation point behaves
like a gas under changes of temperature and pressure ; if it is compressed
TABLES
295
or cooled it reaches a point where it begins to condense ; it then no
longer obeys the same laws as a gas.
Heat and Work required to generate 1 Ib. of Saturated Steam at 212F. from
Water at 32F.
Distribution of Heat.
Units of Heat.
Mechanical
Equivalent in
foot pounds.
THE SENSIBLE HEAT
1. To raise the temperature of the
water from 32-212 ....
THE LATENT HEAT
2. In the formation of steam
3. In expansion against the atmo-
spheric pressure . . . ~
180-9
894-0
71-7
140,740
695,532
55 783
TOTAL OF \VORK
1,146-6
892 055
TABLE XXVII. Factors of Evaporation.
Gauge Pressure of Steam in pounds per Square Inch.
20
40
60
80
100
Temp, of
Feed
Water.
120
150
180
200
187
1-201
1-211
1-217
1-222
1-227
32
231
236
240
1-243
179
1-193
1-203
1-209
1-214
1-219
40
222
227
232
1-234
168
1-182
1-192
1-198
1-203
1-208
50
212
217
221
1-224
158
1-172
1-182
1-188
1-193
1-198
60
202
207
211
1-214
148
1-162
1-172
1-178
1-183
1-188
70
191
196
200
1-203
137
1-151
1-161
1-167
1-172
1-177
80
181
186
190
1-193
127
1-141
1-151
1-157
1-162
1-167
90
170
176
180
1-183
1-117
1-131
1-141
1-147
152
1-157
100
160
165
170
1-172
1-106 il-120
1-130
1-136
141
146
110
150
155
159
1-162
1-096
1-110
1-120
1-126
131
136
120
140
1-145
149
151
1-085
1-099
1-109
1-115
120
125
130
129
1-134
138
141
1-075
1-089
1-099
1-105
110
115
140
119
1-124
128
131
1-065
1-079
1-089
1-095
100
105
150
109
1-113
117
120
1-054
1-068
1-078
1-084
089
094
160
098
1-103
107
110
1-044
1-058
1-068
1-074
079
084
170
088
092
096
099
1-033
1-047
1-057
1-063
068
073
180
1-077
082
1-086
089
L-023
1-037
1-047
1-053
1-058
063
190
1-066
071
1-076
078
1-013
1-027
1-037
1-043
1-048
053
200
1-056
061
1-065
068
1-004
1-017
1-027
1-033
1-038
043
210
1-046
051
1-055
1-057
1-002
1-000
212
Formula from which the above figures are calculated
H=TS-TW.
TS = Total amount of heat contained in one pound of steam at
absolute steam pressure column 4, Table XXVI.
TW = Total heat of water at feed water temperature column 3
Table XXV.
H =Heat imparted to water (TW to convert into steam TS),
LS=Latent heat of steam at atmospheric pressure 965-7.
F= Factor of evaporation.
296 LIQUID FUEL AND ITS APPARATUS
Saving effected ~by heating feed water.
The saving in fuel effected by heating feed water can be calculated
by formula as below
100 (T t)
Percentage of saving = TT_+
in which T= heat units in one pound of feed water above after
heating column 3, Table XXV.
t =heat units in one pound of feed water above before
heating column 3, Table XXV.
H=heat units in one pound of steam of boiler pressure above
column 4, Table XXVI.
TABLE XXVIII.
Heat Balance or Distribution of the Heating Value of
the Combustible.
TOTAL HEATING VALUE OF 1 LB. OF COMBUSTIBLE B.Tn.U.
B.Th.U. =.
per cent.
1. Heat absorbed by the boiler = evaporation from and at
212 degrees per Ib. of combustible x 965-7.
2. Loss due to moisture in coal=per cent, of moisture
referred to combustible + 100 x [(212 - 1) x 966 X 0-48
(T-212)]. (t = temperature of air in the boiler
room, T=that of the flue gases).
3. Loss due to moisture formed by the burning of hydrogen
=per cent, of hydrogen to combustible -^by 100 x 9
X[(212-tx 966x0-48) (T-212)].
*4. Loss due to heat carried away in the dry chimney gases
=weight of gas per Ib. of combustible X 0-24 x (T t).
f5. Loss due to incomplete combustion of carbon
CO , x per cent. C in combustible
-" -x 10-150
6. Loss due to unconsumed hydrogen and hydrocarbons,
to heating the moisture in the air, to radiation, and
unaccounted for.
(Some of these losses may be separately itemized
if data are obtained from which they may be cal-
culated. )
TOTALS
100-00
* The weight of gas por Ib. of carbon burned may be calculated from the gaa
analysis as follows
Dry gas per Ib. carbon - 11 CQ 2 + 8 O + 7 (CO N)
3 (C0 2 + CO)
in which CO2, CO, O, and N are the percentages by volume of the several gases.
The weight of dry gas per Ib. of combustible is found by multiplying the dry gas per
Ib. of carbon by the percentage of carbon in the combustible and dividing by 100.
Professor Jacobus recommends the use of the following formula for finding the
weight of air per Ib. of carbon
C 7 N .
3 (C0 2 + CO) '
t CO2 and CO are respectively the percentage by volume of carbonic acid and car-
bonic oxide in the flue gases. The quantity 10 150 =number of heat units generated
by burning to carbonic acid one Ib. of carbon contained in carbonic oxide.
TABLES
297
TABLE XXIX.
Showing Heat Loss in Chimney Gases according to Percentage of
Carbon Dioxide and Temperature Efficiency.
fyO 50 60 70 80
8 9 10 12 1Z 13 11,. 151617
90
10
mz
1076
10t>0
WOtf.
968
93Z
896
860
821,
783
752
716
680
6k&
612
572
536
500
1+61*
t<Z6
392
356
3ZO
54
zt*a
Z12
176
ll+O
/04
68
31
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INDEX
A
Abergele accident, 184
Acetylene, 289, 82
Adiabatic compression, 242
Admiralty flash tests, 130
Ados, Co 2 recorder, 236
Advantages of Liquid Fuel, 55
Aerated fuel system, 267
Air, atomizing by, 133, 222
calculation of, 247
compression, 242
- efflux, 238, 248
- for atomizing, 133, 214, 222,
247
for combustion, 37, 40, 288, 290
for combustion, Rankine, 114
for combustion, Longridge, 1 14
heater, 166
heater, Ellis & Eaves, 223
heating, 166
lift pump, 33
low pressure, 212, 269
power to compress, 242
pressure diagram, 242
properties of, 82
regulator, 202
tuyere, 202
Alcohol, 282
Allest atomizer, 261
Allo tropic forms of carbon, 78, 1 15
Alsace oil, 46, 281
American gallon, 44
American locomotive practice, 162,
178
petroleum, 44
- petroleum production, 26
stationary practice, 195
Amorphous carbon, 78
Analysis of Borneo oil, 208, 212
- chimney gas, 233
- coal, 112
- firebrick, 70, 71
- fireclay, 70, 71
299
Analysis of flame, 118
- flue gases, 233
oil, 48
petroleum, 48
Texas oil, 48
Anthracite, 139, 116, 111
Anticline, 30
Apparatus, Orsat's, 236
Arch, firebrick, 67
Area of chimney, 239
Arlberg tunnel, 171
Arndt econometer, 236
Astatki, 36, 65, 208
Atmosphere, 82
Atomizers, various, 37, 250
Atomizer Aerated Fuel Co., 250
Baldwin, 179, 250
Bereznef, 37
Billow, 196, 207, 250
- Circular, 36, 262
d' Allest, 261
elementary, 256
flat jet type, 264
Fvardofski, 262
Gregory, 265
Guyot, 250
Holden, 157, 250
Hoveler, 267
hydroleum, 250
Kermode's, 250
Korting, 153, 250
nozzles, 259
Orde, 144
power of, 259
proportions, 261
Rusden-Eeles, 134, 250
Soliani, 263
Southern Pacific Railway, 264
Swensson, 250
types of, 250
Urquhart, 193, 250
Wallsend, 148
Williams, 56
Atomizing, 42, 214
300
INDEX
Atomizing, M. Bertin on, 153, 259
agent, 214
necessity of, 42
with air, 133, 214, 222, 247
with steam, 133, 214, 222
Aude, T, 259
Baku petroleum, 53
Baldwin atomizer, 179
- firebox, 180
oil fuel system, 179
Ballast tanks, 129
Barometer, 83
Barrels of oil produced, 26
and gallons, 49
Beaumont oil, 39, 50
tests, 56
Bereznef atomizer, 36
Berthelot on carbon, 79
Berthelot-Mahler calorimeter, 91
Berthelot on latent heat of carbon,
79
Bertin on air compressing, 246
on atomizing, 153
on liquid fuel, 37
on mixed system, 37, 172
on ratio of oil and coal, 38
Billow atomizer, 207
- system, 195
Bituminous fuel combustion, 40,
116, 112
Blast furnace gas, 283
oil, 41, 47
Blast pipe, variable, Macallan's,
170, 240
Blocks, fireclay, 41
Boiler, Belleville, 110
choice of, 24, 25
water, capacity of, 132
Cherbourg, 264, 176
Du Temple type, 146
firefloat burner, 219
French torpedo boat, 38
Godard, 258
Guyot, 176
hydroleum special, 215
- Lancashire, 145, 167, 168
Lancashire, Orde's system, 145
locomotive, 154
marine, 133
- marine type, 173
Solignac, 25
underfired tubular, 205
water capacity of, 24
Boiler, water tube, 169, 206
without grate, 169, 206, 213
Weir, 40, 121
Boiling point of petroleum, 64
Boring oil, 31
Borneo oil, 212, 63, 208
Brick, see Firebrick
Brick arch, 67
linings, 67
Bridge walls, 40
British Thermal Unit, 294
Buffle, 259
Bulkheads, 128
Bunker pipes of oil supply system,
137
Bunker pump, Weir's, 231
fuel oil, 231
Burma oil, 281, 63
Burner, Clarkson-Capel, 218
Burners, see Atomizers, 250
- Symon House, 257
Burning of firebrick, 69
Butane, 62
C
Calculation of temperatures, 100
Californian petroleum, 44, 45
Calorific formula, 90
Calorific power of Borneo oil, 63
Burma oil, 63
carbon, 78
Caucasus oil, 63
gases, 283
hydrogen, 81
liquid fuel, 53, 99, 281, 284
Clavenad on, 107
Texas oil, 53, 63
Calorimetry, 91, 236
Calorie, 90
Calorimeter, Berthelot-Mahler, 2 37
Canada oil, 281
Capacity of boilers, water, 132
Cap damper, chimney, 240
Carbolic acid, 47
Carbon, allo tropic forms, 78, 115
amorphous, 78
as fuel, 78
- atomic weight, 78
- bisulphide, 79
calorific power of, 78
combustion of, 79
diamond, 78
dioxide, 79
gaseous, 79
INDEX
301
Carbon, graphitic, 78
heat of combustion, 78, 285
heat of conversion, 78, 79
in nature, 78
"liquid," 45, 79
monoxide, 78
properties of, 78, 285
solid, 78
vapour, 79
Carbonic acid, 78
oxide, 78
Carborundum, 67
Cargo steamer, ordinary with oil
fuel, 127
Car hose, tank, 201
Carriage of oil, 35, 228, 139
Casing, 33
Cast iron, 66
Cement for oil pipes, 128
Centigrade thermometer, 93
Chamber, combustion, 73, 123
Charcoal, see Amorphous carbon
Chemical properties of air, 82
carbon, 78
hydrogen, 81
nitrogen, 84
oil, 62
oxygen, 83
petroleum, 62
Texas oil, 45
Chemistry, Thermo-, 90
Cherbourg, test at, 175
boiler, 176, 264
Chicago Exhibition, 21
Chimney area, 239
damper cap, 240
draught, 237
gases, 297
Circular atomizers, 36, 262
Classificationof fireclay goods, 76
Clarkson-Capel burner, 218
- preliminary heater, 219
system, 218
Clavenad on calorific capacity of
fuel, 107
Clay, see Fireclay
CO 2 analysis, 233
in furnace gases, 233
recorder, Ados, 236
recorder, Arndt, 236
Simmance Abady, 236
Coal, analysis of, 112
anthracite, 116, 139
combustion of, 108
long-flaming, 117
Coal, short-flaming, 117
Welsh, 117
and oil furnace, 134
and oil, comparative cost, 132,
183, 286
production, 22
tar, 41
Coefficient of expansion, oil, 129,
281
water, 85
gases, 282
Cofferdams, 128
Coils, heating, 140, 155
Combustion, air for, 37, 288, 290
oxygen for, 288, 290
of anthracite, 116, 139
of bituminous fuel, 40, 112, 116
calculations, 78, 100
smokeless, 108
of carbon, 79
of hydrogen, 81
chamber, refractory, 123
chamber, 73
imperfect, 108
heat of, 63, 109, 288
of liquid fuel, 63
of hydrocarbon, 109
of vaporized liquids, 218, 257
principles of, 39
temperature of, 100
volume of gases, 103
Comparative costs, oil and coal,
36, 59
Compounds, hydrocarbon, 62, 112
Compression, adiabatic, 242
of air, 242
compound, 242
diagrams, 242
isothermal, 242
Conversion, metamorphic, of car-
bon, 78, 115
Construction of furnace, 203
Controlling valves, 160
Corsicana petroleum, 51
Cost, comparison of coal and oil,
35, 183
of oil, 36
"Cracking," 52
Cranes, oil, 230
Creosote, 41, 46
Cresylic acid, 47
Crude oil, 41, 44, 281, 284
Curves of compression of air, 244
Curves of performance, Grazi-
Tsaritzin Railway, 194
302
INDEX
d'Allest's atomizer, 261
Damper, chimney cap, 240
Danger of oil, 36
Density of petroleum, 49, 65, 183
Denton, Prof., on Texas oil, 59
evaporative duty, 59
cost of oil, 59
Deterioration by storage, 65
Diamond, 78
Diesel engine, 270
Dinas firebrick, 67
Dissociation of steam, etc., 87, 97
- gases, 97, 102
Dioxide of carbon, 78
Distillation, fractional, 48
Distribution of liquid fuel, 228
Dowlais firebrick, 67
Draught, 237
Draught gauge, 239
Dudley's formula for relative cost
of oil and coal, 183
Dutch Navy, 130
Dulong's formula, 91
E
Earnshaw on Texas oil, 51
Econometer, Arndt, 236
Economics of liquid fuel, 35
Efficiency of evaporation, 58
Texas oil, 56
Efflux of air, 238, 248
Elementary atomizer, 256
Ellis & Eave's air heater, 223
system, 222
Endothermism, 90, 92
English locomotive practice, 154
stationary practice, 208
Ethane, 62, 82, 202, 282, 289
Equivalent, Joule's, 285
mechanical, of heat, 285
Evaporation, factors of, 295
per unit of various fuels, 104
Evaporative duty, 59, 104, 291
efficiency, 58
Everhart on Texas oil, 48
Exothermism, 38, 92
Expansion of oil, 129, 281
water, 85
Explosions, 229
Factors of evaporation, 295
Factor, load, 24
Fahrenheit thermometer, 93
Feed, oil, 161
Firebox, American locomotive,
163, 171
Baldwin, 180
Cherbourg boiler, 176, 264
Holden, 165
Lancashire, 167
locomotive, 168
Southern Pacific, 171
Urquhart, 188
Firebricks, 67
aluminous, 76
Firebrick, analysis, 70, 71
arch, 67
burning, 69
classification, 76
carborundum, 67
carboniferous, 96
Dinas, 67
Dowlais, 67
French, 67, 70
general particulars, 67
Glenboig, 67
manufacture, 67
Newcastle, 67
Pearson, 68
silica, 70
Stourbridge, 67
Fireclay, analysis, 70, 71
blocks, 41
Dinas, 67
Dowlais, 67
Gartcosh, 73
Glenboig, 67
Kilmarnock, 71
Newcastle, 67
Stourbridge, 67
Flame, 117
testing, 118
length, 38, 117
Flannery-Boyd system of oil fuel,
129, 136
oil storage, 127
Flash point, 39, 65, 130
Flue gas analysis, 233
Forbin, test of, 177
Forced draught, 240
Fractional distillation, 48
French firebrick, 67
French Navy tests, 175
Fuel, evaporative, power of, 69,
104, 291
gas, 283
oil, 212
INDEX
303
Fuel, oil bunker, 142
oil distribution, 228
oil production, 26
pumping, 231
pump, Weir's, 231
oil tanks, 229
Furieux, tests with, 175
Furnace, Ellis & Eaves', 222
- brickwork walls, etc., 146
- construction, 203
- Lancashire, 145, 165
- firebricks, 67
lining, 39, 111, 146
locomotive, 168
management, 187
marine, 133, 173
oil and coal, 211
oil, 209
- temperatures, 112, 81, 293
water tube, 213
Fvardofski atomizer, 262
system, 262
G
Gallon, American, 44, 183
English, 182
Gallons, per barrel, 183
Galician oil, 53
Ganister, 67
Gartcosh fireclay, 73
Gas, analysis, 233
blast furnace, 283
density, 285, 290
dissociation of, 97
expansion of, 282
fuel, 283
hydrogen, 283
marsh, 283
sp. heat, 283, 284
tar, 43, 47, 214
Gases, calorific capacity of, 283
of combustion, volume of, 103
chimney, 297
Gaseous carbon, 79
Gauge, draught, 239
Gear, marine furnace, 133
General arrangement, 137
Korting system, 152
General considerations, 21
Geology, 28
German oil, 281
Glass, violet, 121
Glenboig clay, 67
Godard boiler test, 258
Graphite, 78
Grate, boilers with, 211
boilers without, 210, 215, 206
Gravity, 99
- specific, 286, 287
Grazi-Tsaritzin Railway, 184
curves of performance, 194
fuel tank, 231
locomotive, 189
oil distribution, 228
tender, 190
Great Eastern Railway, 154
locomotives, 165
storage system, 223
tender, 165
Griffin Engine, 270
Guyot atomizer, 254
boiler, 176
Hanover oil, 50, 53
Hard water, 88
Howden's system, 133, 143
Heat, 92
of combustion of carbon, 80, 99
of combustion of petroleum,
etc., 108, 109
latent, of carbon, 90
of dissociation, 79
latent, 96
mechanical equivalents of, 98
of metaphoric conversions, 78
quantity of, 92, 97
specific, 94
thermometric, 92
units, 90
Heater, Clarkson-Capel prelimin-
ary, 218
Ellis & Eaves air, 223
Heating air, 166, 223
coils, 223
oil, 263
Holden atomizer, 157
system, 154
Hornsby Engine, 282
Hose, 201
Hose, tank car, 201
Hoveler system, 267
Howden's system, 133, 143
Hydrocarbon compounds, 62,112
combustion of, 109
Hydrogen, calorific power of, 81
combustion of, 81
gas, 81
304
INDEX
Hydrogen properties of, 81
- temperature of ignition, 82, 119
Hydroleum special boiler, 215
atomizer, 250
system, 214
Ignition temperature, 82, 119, 292
Imperfect combustion, 102
Indret, tests at, 176
Injector, see Atomizer
Interchange of coal and oil, 134
Iron, cast, 66
Isothermal compression, 242
Japanese railways, 162
Jeanne d'Arc, the, 174
Joule, Dr., 98
K
Keller, tests by, 37
Kelvin law, 26
Kermode's atomizer, 250
system, 208
Khodoung, s.s., 143
Kilmarnock fireclay, 71
Kilns, oil fired, 74
Kimeridge clay, 28
Korting atomizer, 153
system, 152
Koudako oil, 49
Laeisz, F. C., s.s., 143
Lamp oil, 43, 218
Lancashire boiler, 145, 167
Latent heat, 96, 113
Latitude and barometer, 83
Length of flame, 38, 117
Lighting up, 187
Lima oil, 184
Lining furnace, 39, 111, 146
"Liquid" carbon, 45
combustion, 38
Liquid fuel, 37
advantages of, 55
at sea, 127
containing oxygen, 47
distribution, 228
economics of, 35
price of, 35, 59
Liquid fuel, production, 26
- properties of, 49, 65, 183
system, Wallsend Slipway
Co., 143, 146
varieties of, 43
Load factor, 24
Locomotive, American, 162, 178
boiler, 154, 178
- Cherbourg, 264
- firebox, 154, 163, 171
Fvardofski, 262
- Great Eastern Railway, 154
- practice, American, 162, 178
practice, English, 154
practice, Russian, 178
Southern Pacific, 171
Vladi Kavkaz Railway, 153
- Urquhart, 184
Low pressure air, 212, 269
Loss by excess of air, 297
M
Mabery on Texas oil, 50
Macallan variable blast pipe, 170.
240
Management of furnace, 187, 204
Manufacture of firebrick, 67
Marine boiler, 173
type boiler, 173
furnace gear, 133, 173
Marsh gas, see Methane
Materials, 66
Mazout or Mazut, see Astatki
Mechanical stoking, 24
equivalent of heat, 98
Metallurgy, application of liquid
fuel to, 267
Metal and refining furnace, 266
Metamorphic conversion of car-
bon, 78, 115
Methane, 22, 82
Meyer system, 172
Milan, test on, 177
Mixed system of coal and oil
combustion, 35, 172
Moat, round oil stores, 228
Monoxide of carbon, 78
Murex, s.s., 127, 133
N
Nacogdoches oil, 48
Naphthalene, 47
National Fuel Oil Co.'s system,
95
INDEX
305
Navy, British, 21, 130
Dutch, 130
French, 175
German, 130
Italian, 258
Russian, 65
Newcastle fireclay, 67
coal, 47, 112
New York, s.s., liquid fuel for, 138
Nitrogen, 84
in atmosphere, 84
properties of, 84
Nozzles of atomizers, 259
Oil, Alsace, 53, 46
American, 44, 46
Baku, 53, 284, 36
Beaumont, 39
blast furnace, 47
boring, 31
Borneo, 63, 212, 208
Burma, 281, 63
California, 44, 54
Canada, 281, 46
Corsicana, 51
creosote, 46
crude, 183, 281, 284, 46
drilling, 32
fuel, 212, 284
- Galicia, 53, 46
- Gold Coast, 49
- Hanover, 50, 53
- Koudako, 49
lamp, 218, 43
- Lima, 184
- Nacogdoches, 48, 51
Pennsylvania, 46, 49, 53, 286
- reduced, 44
- residuum, 36, 42, 287
- Roumanian, 46, 49
- Russian, 46, 286
- shale, 47
- Sour Lake, 51
Texas, 45, 49
Wyoming, 86
Zante, 49
and coal, comparative cost, 38,
286
- and coal furnace, 136
burner, see Atomizers
calorific power, 281, 284
carriage of, 35, 139, 228
- cranes, 231
Oil engines, 271
expansion, 129, 281
explosions, 229
distribution, 228
feed, 161
Oil furnaces,
furnace, Baldwin, 178
engines, 271
- Cornish, see Lancashire
Holden, 165, 168
Lancashire, 168
locomotive, 154-178
- water tube boiler, 169
Oil heating, 263
pressure, 269
pipes, 229
pump, 231
pumping system, 196, 32
ratio to coal, 54
regulation, 161, 179
regulator, 161, 179
safety moat, 228
service pumps, 196, 231
steamers, recent, 1'29
storage, 127, 228
stratification, 30
tank steamer, 138
Orde atomizer, 144
boiler, Lancashire, 145
on liquid fuel, 63
system, 140, 143
water-tube boiler, 141
Orsat-Lunge apparatus, 236
Oxygen, 83
Packman, s.s.. 133
Pakin, test on, 177
Paraffin, 221
Paul, Dr., on liquid fuel, 62
Pearson firebricks, 68
Pelouze and Cahours on hydrocar-
bons, 64
Pennsylvania oil, 49, 286
Performance curves, Grazi-Tsarit-
zin Railway, 194
Petroleum
American, 44
- analysis of, 48
- Baku, 53, 284
- Borneo, 212, 63
- Burma, 281, 63
boiling point, 64
California, 44, 54
- combustion of, 109, 218, 257
306
INDEX
Petroleum, Corsicana, 51
- drilling, 32
fuel, 183
geology, 28
production of, 26
properties of, 49, 65, 183
pumping, 32
residuum, 36, 42, 287, 291
Russian, 46, 286
storage precautions, 228
- Texas, 45, 49
Phillips on Texas oil, 49
Physical properties of oil, 49, 65,
183
Pipes, 88, 229
bunker, 128, 137
jointing, 128
jointing cement, 128
water, 88
Pood, its equivalent, 230
Power to compress air, 247
Precautions in oil storage, 228
Preliminary heating, 218
Pressure systems, 196
Price of oil, 35, 59
per barrel, 36, 54, 59
per gallon, 36, 44
Principles of liquid fuel combus-
tion, 38
Production of coal, 22
Propane, 62, 82
Properties of air, 82
American oil, 44, 46-
Borneo oil, 63, 208, 212
carbon, 78, 285
firebricks, 67
fireclay 67
gases, 283
hydrogen, 81
liquid fuel, 49, 65, 183
nitrogen, 84
oxygen, 83
petroleum, 49
Russian oil, 46, 256
Texas oil, 45, 51
water, 84
Proportions of atomizers, 261
Propylene, 82
Pulverizers, see Atomizers
Pump, Weir's bunker, 232
Weir's oil, 232
Pumping systems, 196
Pumps, oil, 231
Pyrometers, 94
Q
Quantity of heat, 92, 97
R
Ragosino effect of steam on oil, 260
Ratio, oil to coal, 38
Reaumur's thermometer, 93
Reduced oils, 44
Refractory combustion chamber.
73
linings, 39, 73, 111, 146
Regulating gear, 161, 179
Regulation of oil, 161, 179
Regulator, air, 202
oil, Baldwin 179
oil, G.E. Rly., 161
Relative cost, oil and coal, 132,
183, 268, 286, 191
Residuum, 36, 42, 197
Ringelmann's smoke chart, 123
Riveting, 128
Roumanian oil, 49
Rules for liquid fuel ships, 127
Rusden-Eeles atomizer, 134
Russian locomotives, 191
Navy, 65
oil, 46
Ruston Proctor Engine, 271
S
Safety moat round tanks, 228
St. Glair Deville, 102
Salts, solubility of, 87
Sea water, 88
Serpollet on vaporizing, 263
Service, oil pumps, 231, 196
.Shale oil, 47
tar, 47
Silica, 67-77
Siloxicon 77
Simmance Abady CO 2 recorder,
236
Siihonia, s.s., 143
Small tube boiler, 1 H
Smoke, 82, 109
chart, Ringelmann's, 123
prevention, 109
Soft water, 88
Soliani atomizer, 263
Solignac boiler, 25
Solubility in water of salts, 87
Soot, 82
Sour Lake oil, 51
Southern Pacific Railway, 36, 54,
171, 264
INDEX
307
Specific gravity, 46, 49, 65, 164
Specific heat, 94
gases, 95
ice, 86
solids, 284
water, 86
Sprayer, see Atomizer
Springfield system, 269
Stationary practice, American,
195
English, 208
Steam, as fuel, 15
atomizing, 133
- dissociation by heat, 87, 97
per pound of oil, 258
ships, F. C. Lacisz, 143
Murex, 127, 133
Neivyork, 139
S-lthonia, 143
Syrian 143
Tanglier, 133
Trocas, 129, 134
Steam, superheated, 294, 143
Steamer, cargo with oil fuel, 127
recent oil, 138
tank with oil fuel, 129
Steel, 66
Steel tubes, 66
Storage of oil, 228
safety moat, 228
system, G.E. Rly., 229
tank, oil, 228
Stourbridge clay, 67
firebricks, 67
Subweolden, boring, 29
Sulphur in oil, 36, 59
Sumatra oil, 49
Superheated steam, 294
Supply of water, 84
tank, oil, 231
system, bunker pipes, 137, 141
Surcouf, test of, 177
Swensson atomizer, 256
Syrian, s.s., 143
System, Aerated Fuel Co., 267
- Baldwin Co., 178
Billow, 195
Clarkson-Capel, 218
distribution, 228
Ellis & Eaves, 222
Flannery Boyd, 136
Fvardofski, 262
Guyot, 254
Holden's, 154
Hoveler, 267
System Howden's, 133 143
hydroleum, 214
Kermode's, 208
Korting, 143, 152
Meyer, 172
mixed, 37, 172
- National Fuel Co., 195
Orde's, 140, 143
- Pumping, 231, 198
- Rusden-Eeles, 134, 143
Springfield, 269
- Symon House, 257
- Urquhart, 184
Wallsend Slipway Co.'s, 143,
146
T
Tanglier, s.s., 133
Tank, car hose, 201
oil supply, 231
steamer, 138
storage, 228
underground, 230
Tar, 41, 43, 47, 214, 237
properties of, 237
water gas, test of, 215
shale, 47
Temperature, 92, 284, 293
calculation of, 100
flame, 112, 259
furnace, 112
of combination, 101
of ignition, 82, 292
Tender, fuel, 186
G.E. Rly., 165
Grazi-Tsaritsin Railway, 186,
190
Test of air atomizing, 226
Beaumont oil, 57
- Borneo oil, 208, 211
Furieux, 175
marine boiler, 222-227
- Texas oil, 56, 48
Tests at Cherbourg, 175, 264
at Birkenhead, 212
at Indret, 176
Godard boiler, 258
Russian oil, 37
Texas oil, 45, 51
analysis, 48, 51
calorific power of, 53
carriage of, 35
chemistry of, 48
costs, 59
308
INDEX
Texas, density of, 49
efficiency of, 56
specific gravity of, 49
tests of, 56
Thermal units, 90, 294
Thermo-chemistry, 90
Thermometer, 93
Thiele on Texas oil, 45, 51
Torpedo boat, 38
boiler, French, 260
Trinidad, 28
Trocas, s.s., 129, 134
Tubular boiler, underfired, 205
Tunnels, Railway, 171
Tuyere, air, 202
U
U gauge, 239
Underfired tubular boiler, 205
Units of heat, 90, 97
thermal, 97
weight, 85, 98
work, 98
Urquhart atomizer, 193
locomotive, 191
system, 184
tender, 188
Useful figures, 87, 89, 292
Vaporization, heat of, 106, 117
Vaporized liquids, combustion of,
218
Vaporizer, 273, 275
Vaporizing, 43, 216, 218, 276
carbon, 78, 79
Variable blast pipe, Macallan's,
170, 240
Varieties of liquid fuel, 43
Velocity of efflux of air, 238, 248
draught, 237
watqr in pipes, 88
Ventilation, 128
Verein-Deutsche ingenieur, 91
Violet rays in flame, 120
Volatile constituents of petro-
leum, 36, 39, 42, 47
Volume and weight of atmo-
sphere gases, 293
gases, 289
petroleum, 183
of combustion gases, 289
W
Wallsend Slipway Co., 143, 146
Atomizer, 148
furnace brickwork, 146
latest system, 149
Warming oil fuel, 263
War vessels, Sir F. Flannery on.
130
Water capacity of boilers, 24
compressibility, 85
data, 85
expansion by heat, 85
flow of, 88
gas tar, 215
gauge, 239
hardness, 88
in oil, 68
latent heat of, 84
pipes, 88
properties of, 84, 294
pure, 84, 294
solubility of salts in, 88
source of, 84
specific heat, 86
supply, 84
useful data, 89
weight, 87
Water-tube boiler, Guyot, 176
Hydroleum, 215
Orde's system for liquid fuel,
140
Wealden, 29
Weir's, 40, 121
without grate, 169, 206
Weight of air, 82, 289
gases, 289
hydrogen, 81, 289
firebrick,
oil, 58
oil per barrel, 58
oil per gallon, 58
oxygen, 84, 289
nitrogen 84, 289
water, 85, 294
Weir's boiler, 121, 40
oil pump, 231
Welsh coal, 117
Williams atomizer, 56
Work units, 98
Wyoming oil, 46
Zante oil, 49
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