WYOMING University of Special Bulletin: Heating Power of Wyoming Coal & Oil SB 3E D77 AGRICULTURAL LIBRARY, UNIVERSITY -~OF CALIFORNIA. UNIVERSITY OF WYOMING. L.IR.AMIE, WYOMING. Departments of Chemistry and Mechanical Engineering. t' (J U SPECIAL BULLETIN. JANUARY, 1895. The Heatinn Power of ffyoiof Coal and Oil With a Description of the Bomb Calorimeter, BY EDWIN E. SLOSSON, Professor of Chemistry, and L. C. COLBURN, Professor of Mechanical Engineering. THE HEATING POWER OF WYOMING COAL AND OIL INTRODUCTORY. The value of a fuel depends upon the amount of heat that can be obtained from it. Although we buy it by weight, it is not matter we want, but energy. Everyone who uses fuel either for heat or power needs to know what is the greatest amount of heat that can be obtained from the kind of fuel used. He can then tell whether he is getting that which is the best, quality for the price paid and also whether he is getting as large a proportion as he should of the total heat. As coal is at present the most important of the mineral resources of Wyoming, it was thought that the State Uni- versity could hardly do a greater service to consumers as well as mine-owners than to make a complete and impar- tial investigation of the relative and absolute value of the coal from different localities. We give accordingly a com- parative table of the heating value of Wyoming coals so far as we could obtain samples of them, and also a table of the fuel value of the crude petroleums of Wyoming. Following this is a description of the calorimeter used, as it is an instrument which will probably come into general use R33530 Wyoming Coal and Oil. and, so far as we know, no complete description of the ap- paratus and its manipulation has yet been published in Eng- lish.* COLLECTION OF SAMPLES. The most essential part of an investigation like the present is the selection of samples accurately representing the coal fields from which they are taken. This task was efficiently performed by W. C. Knight, Professor of Geol- ogy in the University of Wyoming, who personally vis- ited most of the coal- and oil-fields of the State during the summers of 1893 and 1894. -J- The samples were obtained by cutting down the whole face of the exposed coal-bed, re- jecting partings and slates, breaking up and dividing until a sample of five to ten pounds weight was obtained. This was shipped to the University, where it was powdered and sampled for analysis. The samples since their preparation have been preserved in glass-stoppered bottles, and it is be- lieved that they have not materially lost in water content. Samples not selected by Prof. Knight were usually taken, by the owner or someone connected with the management and are indicated by the letter O; for them, of course, the University assumes no responsibility, although there is no reason to doubt the fairness of the selection. If any import- ant coal-mines have been omitted from this investigation it is not the fault of the Universitv, as announcements of the work in progress and requests for samples have been often published during the past two years. *The best brief account of thermo-chemical principles and processes known to the writers is Bertholet's "Traite Pratique dc Calorimefrie C/iiinigite." (The coal samples obtained in 1894 were burned in the freight car in Laramie. Wyoming Coal and Oil. 5 EXPLANATION OF TERMS. There are so many different units of heat and energy in use that it was thought necessary to calculate results in three of the more common forms to facilitate comparison. A calorie is the amount of heat required to raise the temperature of one gram of water one deg. centigrade. The conception can, however, be generalized, and the statement that a gram of coal produces 6,000 cal. may be interpreted to mean that the heat produced by the combustion of one pound ot coal would raise the temperature of 6,000 pounds of water i degree C. (1.8 Fahrenheit) or 600 pounds of water 10 de- grees, etc. A foot-pound is the amount of work required to raise the weight of one pound to the height of one foot against the force of gravity. A horse-power is 33,000 foot-pounds per minute, so dividing the number of fool-pounds per pound by 33,000 will give the number of horse-power developed by burning a pound of coal per minute Of course only a very small fraction of the potential energy of the fuel can be converted into mechanical energy by even the most per- fect heat engines known. The third column gives the number of pounds of water which could be evaporated or converted into steam by the combustion of one pound of the coal under a pressure of one atmosphere; the water being regarded as already heated to the boiling-point, 100 C. or 212 Fahr. THE COAL TESTS. The accompanying table gives all the coals so far tested, arranged in the order of their heating value. The figures given represent the total amount of heat obtainable by per- fect combustion. No more heat can be obtained from the Wyoming Coal and Oil. fuel by any method of firing; on the contrary, as shown below, only about half the heat can be made available in steam production, and in common practice a still smaller proportion is usually obtained. In general, a larger propor- tion of the total amount of heat can be obtained from a good coal than from a poor one. In some cases, however, as where slow burning is required, a coal containing a consid- erable quantity of ash or even water will give better results than one of greater heating power per ton. It should be borne in mind that the table gives the amount of heat, not the intensity, as that depends on the rate of combustion. The highest degree of heat attained in these tests was apparently from the pine knot which burned so fiercely as to melt into a ball the end of a platinum rod of 1.8 mm. diameter. In one respect there is an important difference between the conditions of combustion in the cal- orimeter and in the open furnace. In the calorimetric bomb the water contained in the coal and the gaseous products of combustion are cooled down to the ordinary temperature while in a furnace the steam and heated gases pass off. To represent their true relative value, therefore, the numbers given should be reduced in proportion to the amount of water contained. In the case of a coal giving 6000 calories but containing 10 per cent, water and four per cent, hydro- gen, the correction would be 283 calories or about 4.7 per cent. Wyoming Coal and Oil. in O J O w o (In O w w H O w PQ H [GOO qj -lOdcAS jo spunoj |T30D jo punod aad spunod-iooj W - ro ro ro ro co ro ro M ' "t" ^ M' - Wyoming Coal and Oil. [ROD qj i Aq ps^-B .loduAS ZIZ }B jo spunoj C/D o . 60 c Q ^ 5 c .cO ON O M fO rO rj- oo'co'co" oc I r'll h *J^=r TABLE OF PROXIMATE ANALYSES OF- WYOMING COAL ! 'J 3 J| 5 ~ c NAME OF MINE. C3 u jj "33 z fcn ^ "" ~~ " -r 15 r; o. "3 s c ^ w /; 3 c JVj & >.5I t. ^1 C/} H I J. Curtis, Ham's Fork i 1.50 37 -9<>| 57-75 2.85 1 OO 95.65 2 Wm. Goodell, Ham's Fork ! 2.9; 38.00154.00 4-5 92.00 3 A. Kendall, 3-75 37.25155.40 3.60 .60 92.65 4 Sweetwater Mine 5-55 36 95 55.70 1. 80 .86 92.65 5 Kindt No. i 4.87 35.68 55.15 4-3 77 90.83 6 Van Dvke (lower vein) 6.25 56.50 2-75 74 91.00 8 Kindt No. 2 5.40135.80 55 65 .70 91-45 10 McCoid 5.05 34.75 5 6 15 45 85 90.90 1 1 Van Dyke (upper vein) 5-67 35-73 56-85 i-75 .68 92.58 13 New Dillon 7-2.S 33-25 54-25 4-25 50 87.50 H Rock Springs No. 2 6.22 3478 55-75 325 1.41 90.58 15 n " " i 5-38 3642 5;. 60 2.60 63 92.02 16 U 4 595 34-5 S 56.10 3-40 I.OO 90.65 ! 7 s 5-95 35-7 55-75 2-55 65 91-45 18 it . u y 6-37 35 *8 54-85 36o .86 90.03 20 Antelope, Cambria 672 39 38 44.25 9-65 3-79 8363 21 Jumbo, 5-72 4013 43.65 10 50 457 83.78 22 Red Canon No. 6 7-75 35- 10 50.60 6-55 29 85.70 23 Carbon No. 2 742 35-43 48-30 8.85 8373 2 4 Rock Springs No. 3 (east face) 7.17 3358 55-6o 3-65 .83 89.18 26 Casper No. i 11.30 32.10 53-55 3-20 .40 85-65 27 Red Canon No. 5 (lower 9 feet) 7.42 3608 48.50 8.00 44 84.58 28 Brown n.8s 34-65 47-30 6.20 1.25 81.9^ 29 30 G. L. Young No. i Almy No. 7 (upper vein) 14.66 7-37 31 51 34-88 50.85 48.75 1.98 1 9.00 56 8366 31 G. L. Young No. 2 14.64 36.70 4645! 2.21 48 83.13 33 Meyer, Carbon I 11 - 1 5 33- 10 53-00 2.75 -65 83.10 Wyoming Coal and Oil. if PROXIMATE ANALYSES OF WYOMING COALS Continued. ^ O ii 6 c toe NAME OF MINE. 'i* U y 0> a ft -1^ *^~ OJ '^ ..c ^ t r^ ,_, ^ 'Zj u ~ d. 15 c3 Bl o '~ X ~~2 -^ 04 ! > > ' ** w ~-> 34 Almy No. 7 (lower vein) 8.8233.5551.75 -5.90 .65 '85.30 35 Mason, Felix 10.5037.0248.46 442 35 '85.48 36 37 38 39 4 4 1 G. L. Young No. 3 Lander Fuel Co. Red Canon No. 5 (middle 2j/ 2 feet) Black Buttes No' i Gilmore Mine Brown (1894) H-23 II.4O 6.8 1 H-45 13.12 11.25 37.4846.07 36 6047.60 36.49147.45 30.07 51.98 33. 1 3 ! 50.40 36.85 45.00 2.22 440 925 350 335 6.90 44 5 .6, 83-55 84.20 83-94 82. os 83-53 81.85 42 Burgess, Sheridan 13.05 37.5544.70 4--7O 7 1 82.25 44 Harper, Sundance 7.88 33.52 43 90 14.70 1.03 77.40 45 46 47 Earl & Gillis Grinnell, Sheridan Deer Creek, Glenrock 13-25 14.42 13-82 34. 2 5 48.00 33.1844.75 33.0347.75 4-50 7-65 5-4 to cr\ co-7 6 to 63-9 9,600 6,080 per cent. Short-flaming caking or coking 9,300 to 9,600 5,888 ' to 6,400 65 per cent. True caking or cokiii"" 8,800 to 5,376 to 62.2 9.300 5,888 per cent. Long-flaming or gas coal 8,500 to 4,864 to 58 8,800 5<3i2 per cent. Long-flaming dry coals.... 8,000 to 4,288 to 55 8,500 4,800 per cent. *An average of 8 tests with boilers of standard make gave 10.45 pounds of water evaporated per pound of coal. An average of 104 vertical boilers gave 12.24 pounds of water evaporated per pound of coal. An average of 73 horizontal boilers gave 11.27 pounds of water evaporated per pound of coal. These tests show what we may expect from an aver- age of good coals under best conditions of boilers and care- ful management. *Taken from Weisbach's Mechanical Engineering. tKent in Mineral Industry for 1892. The coal is calculated as free from ash and water. 14. Wyoming Coal and Oil. The comparisons would be of more value if the heating- power of the coals had been given. In these boiler tests it is shown that only 45 per cent, to 85 per cent, of theoretical evaporation power is obtained in practice. In a recent test made with a Heine boiler with two kinds of coal two results are shown: with coal of 6,m cal- ories it gave 66 per cent, efficiency and with coal of 7,344 calories it gave 76 per cent, efficiency. If these results be carefully studied it shows this fact plainly: the better the quality of the fuel the greater the ef- ficiency of the boiler, thus giving double results from the use of the heat fuel; not only is there a gain in amount of fuel saved but also a gain in efficiency. In the use of Wyoming coal for power purposes some- what different management is needed than with the eastern coal. As they have but little coking properties upon the grate they have a tendency to split up into small pieces and pass through the bars; this is easily overcome by using fine grate bars. The splitting up has also a tendency to cause smothering of the fire; this may be prevented by hav- ing a wide dead plate in front on to which most of the fuel is placed; here it is gradually heated and the volatile parts in passing off have to pass over the ignited coal upon the grate and will be entirely consumed, if proper arrangement is made to supply fresh air. The heated coal can then be pushed back upon the bars. Thin fire-bed with frequent firing also gives best re- sults; regulation of draft is best accomplished with the use of a damper in the stack rather than by ashpit and furnace doors. With our vast coal-fields but little prospected and the Wyoming Coal and Oil. 15 large yield of coal from those already opened it would seem as if efforts to obtain highest efficiency are not necessary, but when we consider that the cost of fuel per ton is greater than in eastern States, our manufacturers must bring down the cost of operation in every way possible if they wish to hold the western market against eastern manufacturers, and this can be done by using the most efficient motive power and the best fuel they can obtain, when the amount of actual fuel is estimated per ton of coal purchased. With two methods of obtaining draught we obtain two different results from burning the same kind of coal with the same boiler. In practice it is found that more air must be supplied than is theoretically required. With natural draught about 24 pounds of air should be supplied per pound of fuel used, while 18 pounds is found sufficient when a blower is used. PETROLEUM AS FUEL. The use of liquid fuel is rapidly increasing during the last three years, the most notable example in this country being that of the power plant of the World's Fair at Chica- go; not being able to obtain the official report we can give no actual data as the results. In Russia many of the rail- roads and the steamers on the Black Sea are now being fired with petroleum or the heavy refuse oils from the re- fineries. From the table below it can be seen that pound for pound the oils of Wyoming possess nearly double the heat- ing capacity of the coals. -In the use of oil for steaming purposes the chief advantages are: ease with which firing can be controlled simply turning a valve will adjust the heat to the desired degree; economy of storage room; free- dom from dirt and refuse from firing. Wyoming Coal and Oil. No complex apparatus is necessary to use oil as fuel. Any method of reducing the oil to a fine spray with either air or steam and of adjusting amount of air necessary for combustion are all that are required. This may be made by any steam-fitter from ordinary steam-pipe and fit- tings. No change, or but little, is needed with boilers as ordinarily set to use the oil as it may be introduced into the furnace through pipes that may pass through the boiler front or through the sides of the fire-box. The use of oil on the railroads of Russia has proved economical because fewer delays are caused in loading up with fuel and no fuel is needed while trains are stopping at stations; the steam pressure can be more easily controlled and no steam is wasted at the safety valve. As the Wyo- ming oils are much like the Russian oils the same results may be expected with their use. The use of oil in iron manufacture is increasing rapid- ly. In the Ohio iron manufactories oil is considered cheap- er at 2 cts. per gallon than coal at $2.00 per ton for heating furnaces in making bolts, spikes, chain and other small work. A comparative commercial test of coal and oil for heat- ing is much to be desired in connection with calorimeter tests. This would show exactly the relative value of the two under ordinary conditions. WYOMING PETROLEUM AND ASPHALT, P s i ^ ."^' ,_ - "03 a. T3 O ^ > *2 LOCATION. MINE. a 1 "o " M 0> a 5 a ^ ^' ^ c jo o a 3 f^ T3 rt cS O *"" Of! y fc a. PH "S "S i Petroleum Bonanza I0. 9 2 7 | ::- 7 u *3 Shoshone Reservation Salt Creek, Natrona Co. 10,883 15,204,000 10,813 15,106,000 22.24 2O. I I *4 lOil Mountain, Natrona Co. 10,747 *5 *6 u Newcastle, Weston Co. " Little Popo Agie, ^ Murphv 10,447 H.595,000 19-43 Fremont Co. ^ Wells 10,430 14,571,000 19.40 7 Asphalt 9,53 2 *8 " Wallace Creek, west of Garfield Park 6,307 *Collected by Prof. Knight. 3 1 8 Wyoming Coal and Oil. METHODS OF DETERMINING HEATING POWER. There are in use three methods of estimating- the heat- ing value of fuels: boiler tests, calculation from analysis and calorimeter tests. 1. The boiler test. By using a weighed amount of the coal in question under as nearly as possible the same conditions as other coals we get a satisfactory practical knowledge of its fitness for the purpose. The disadvantages of this method are the difficulty and expense of testing a large number of samples in this way, and the fact that since only a small proportion of the heat can be obtained in its equivalent of steam pressure or mechanical movement, the experiment is alw r ays a test of the efficiency of the furnace and boiler and of skill in firing, instead of a determination of the absolute value of the fuel. In other furnaces or under other conditions the results might be reversed. It is only in an experimental plant where all the factors, such as the tem- perature and volume of the entering air and escaping gases, composition of the coal, temperature of the water and pres- sure of the steam, losses from radiation, etc., can all be measured, that the absolute heating power can be found. With accurate work under such conditions the total amount can be accounted for to within a few per cent.* 2. Calculation of heating power from chemical analy- ses. The proximate analysis of coal gives, as may be seen from the tables of analyses and calorimetric tests in this bul- letin, a fair idea of the relative value, since of course the greater the amount of water and ash the less the per cent, of fuel. No accurate valuation can, however, be made on the basis of proximate analysis, since the composition of the volatile combustible matter and even of the "fixed carbon" *Rowan and Mills: Fuels. Page 731. Womin Coal and O?L is not definite and the dividing line is not exact. Elementary analysis affords a better basis for the calculation, and if the sample belongs to a well-defined class which has been suffi- ciently studied, the application of the proper formula usually gives a close approximation to the calorimetric result.* No formula can of coarse give exact results because the ele- ments, carbon, hydrogen and oxygen, exist in compounds having different heats of formation and consequently of com- bustion. Elementary organic analysis is a much longer and more delicate process than the direct determination of heat- ing value with the calorimeter. 3. Calorimetric tests. The most satisfactory method of finding the heating power of a fuel is to burn a small sample under such conditions as admit of measuring the amount of heat evolved. This is done by carrying on the combustion inside a vessel filled with a known weight of water of a certain temperature. There are two kinds of combustion calorimeters; in one the fuel is mixed in a small diving-bell with salts such as potassium chlorate and nitrate which supply the oxygen, in the other it is burned in com- pressed oxygen. An instrument of the first class, Thompson's calorime- ter, has on account of its cheapness and convenience been extensively employed in England and the United States in the valuation of fuels. The process is liable to many errors, some of which, being variable, it is impossible to correct. These errors are chiefly due to losses of heat through the escaping of imperfectly cooled gases, the -solution of the oxygrn salts and their products in the water, irregular heat- *The difference is about 3 per cent. See a valuable article by Wm. Kent on the heating power of coal in The Mineral Industry for 1892, Vol. I, page 97. 20 Wyoming Coal and Oil. ing of the thick glass vessel, and particles of carbon which are kept from burning by the melting salts. The correction for loss of heat is stated by the manufacturers to be TO per cent.; it has been estimated,* however, at 30 per cent, and in fact no constant correction can be used. In using the in- strument on Wyoming coals we found it necessary to add a considerable quantity of some auxiliary combustible which complicates the reactions. Even when it is constructed for scientific instead of technical work and the most elaborate precautions are taken as in Stohmann's investigations^ a calorimeter of this kind gives inferior results and it is now abandoned in favor of the simpler and more exact bomb calorimeters. DESCRIPTION OF THE BOMB CALORIMETER. The essential conditions for the determination of heat of combustion are that the product be completely burned, that the heat pass entirely into the water of the calorimeter vessel and that the combustion be as quick as possible. These conditions are best attained by the process devised by Berthelot, according to which the combustion takes place in a closed steel vessel (the so-called bomb) filled with oxy- gen under twenty to twenty-five atmospheres pressure and almost entirely immersed in the water of the calorimeter. Under these circumstances a hydrocarbon burns completely to carbon dioxid and water in a few seconds, none of the products of combustion can escape and the heat passes into the surrounding water in the course of two or three minutes. The high price of Berthelot's calorimeter, about $1,500, has prevented it from coming into common use. In June, 1892, *L. I. Blake: Kansas Academy of Sciences, 1888, page 42. "j"Kalorimetrische Untersuchungen von F. Stohmann, Landvvirth- schaftliche Jahrbucher, 13, page 513. Wyoming Coal ami Oil. 21 an account was published* of a modification of Berthelot's apparatus invented by M. Mahler in which the expensive platinum lining of the bomb was replaced by a thin coating of enamel without impairing the efficiency of the instru- ment. A calorimeter of this kind was procured by the University of Wyoming^ in July, 1894, for the study of the coal and petroleum of the State and for use in food investi- gations in the Agricultural Experiment Station. As we have had many inquiries about this instrument and its workings we give a description with a cut. The bomb (B in cut) of our apparatus is 15 centimeters high and ten cm in diameter, with an average thickness of eight mm. It is Martin-Siemens soft-forged steel of a re- sistance of 50 kilogrammes per square millimeter of square section and 20 per -cent, elongation. It is nickel-plated on the outside and coated on the inside with a thin white enamel to prevent corrosion by the oxygen and the acids which are among the products of combustion. The capacity of the bomb is 580 cc. A platinum tray (C) of 30 mm in diam- eter and 5 mm in depth;}; is suspended from the cover by a rod of platinum. A similar rod passing through the cover but insulated from it reaches nearlv to the tray and serves as the other electrode. The cover is screwed on over the top of the bomb and a hermetical joint secured by a ring of *Bulletin de la Societe d'Encouragement pour 1'Industrie Nation- ale, Paris. fT he apparatus is constructed by M. L. Golaz. Rue Saint-Jacques, Paris, and is sold at the following prices: Mahler's calorimeter complete 750 francs, pump for compressing oxygen 500 franc-*, pair of thermometers 50 francs. Our instrument was procured through Eimer and Amend, N. Y. A cheaper form of the bomb calorimeter which dispenses with pump or gas cylinder is described in Hempel's Gas Analysis. JThis is heavier and deeper than the one sold with the apparatus. 22 Wyoming Coal and Oil. lead. The oxygen is passed in through the stem of the needle valve, which is- screwed down when the bomb is filled. The bomb is set in a support which touches the bottom of the calorimeter vessel on three points. The cal- orimeter vessel is a pail of thin brass, twenty-three centime- ters high and fourteen centimeters in diameter. This rests on three points of a light wooden support and is surrounded bv a large double-walled vessel covered with thick felt con- taining water at the normal temperature of the room. An ingenious stirring mechanism enables one to keep the water of the calorimeter in thermal equilibrium with slight effort. The calorimeter is so well isolated from external influences that the water often does not vary in temperature a hun- dredth of a degree in fifteen minutes, although the air of the room may be quite variable. Two thermometers were used, one reading between eight and eighteen degrees C. and the other between eight- een and twenty-eight degrees; each degree covering a space of 3^ centimeters. They are graduated to a fiftieth of a degree and were read to one-hundredth, although with a glass they can be read to a much finer interval. The oxygen used was made in the laboratory, purified by passing through a solution of caustic potash and three rolls of copper gauze, and kept in gas-bags; the slight cor- rection indicated for Berthelot* for the loss of heat through vaporization of water has not been applied. *Comptes Rendus, 114. p^-6, 6-7, 7-8, 8-9, the- total loss .0021 deg. The temperature rose .01 deg. during the preliminary period or .002 degree per minute. The correction for the half minute 5-5^ is therefore .001. The total rise in tempera- ture is from 11.48 deg. to 13.64 deg. or 2.16 deg.; adding to this the correction .02 deg. gives 2.18 deg. for the true rise due to combustion. The water value of the apparatus, 491 g., added to the weight of water used, 2,300 g., gives 2,791 g., which multiplied by 2.18 gives 6,084.4 calories. The weight of the barium sulphate with the decimal point moved two places to the right gives 4.7 to be subtracted from 9.0 cal. leaving 4.3 cal. The weight of the wire, .0250 g., multiplied by 1650 gives 41.2 cal. The sum of the corrections for formation of iron oxid and nitric acid, 45.5, subtracted from 6,084.4 gives 6,039 calories for the Coal and Oil. true heat of the combustion of one gram of the coal. The use of Regnault's formula in this case would make the rise of temperature 2.179 ^eg. anc ^ tne heat of combustion 6,036. NOTES ON CALORIMETRY. The use of a cylinder of oxygen under great pressure such as is now in the market, dispenses with a compres- sion pump, and shortens the time required for a combustion by one-half. It has the disadvantage that the quality of the oxygen is not as much under control as where it is made in the laboratory. It is not necessary that the coal should be finely pow- dered, nor is there any difficulty in using fine samples. Of the samples used, one was in coarse fragments and some had been passed through a hundred mesh seine. In using very fine coal or freshly sublimed naphthalene, it is conven- ient to compress it into tablets with a "diamond mortar" such as is used in crushing minerals for analysis. The cylinder of the compression pump must be kept cool by a water jacket, or the oil will become ignited by the compressed oxygen and an explosion result. The rapidity with which the heat is given up to the water of the calorimeter is shown by the following average of ten determinations: Heat given off during the period 5-5^-^27.9 per cent. it 44 44 44 44 44 44 44 44 6-7 2O. I 7~8 _______ 1.7 IOO.O " ' ; That is, 78.2 per cent, of the total heat is absorbed by the water during the first minute and 98.3 per cent, during the first two minutes. Care must be taken to scrape off the iron oxid from the electrodes before attaching the new wire, as a very thin film will prevent ignition by the electric current. R33539 THE UNIVERSITY OF CALIFORNIA LIBRARY