One pound of anthracite coal, composed of carbon 85 per cent, hydro-carbons 5 per cent, and ash 10 per cent, will make 90 cubic feet of producer gas of the following composition: hydrogen 12 per cent, carbon monoxide 27 per cent, marsh gas 1.2 per cent, carbon dioxide 2.5 per cent, and nitrogen 57 per cent, having a heat value of 137 heat units per cubic foot. This gives an equivalency of about 104 cubic feet of gas to one pound of anthracite coal, or 1,000 cubic feet to about 9.5 pounds of coal.
Comparison of Anthracite Gas and Bitumi nous One hundred pounds of anthracite coal converted into gas in a gas producer yields 186.66 pounds of carbonic oxide, equivalent to 807,304 B. T. U.; 5 pounds of marsh gas, equiva lent to 117,500 B. T. U.; and 3.75 pounds of hy drogen, equivalent to 232,500 B. T. U. ;- a total of 1,157,304 B. T. U. The total energy per pound of gas is 2,248 B. T. U. Since the total energy in 100 pounds of anthracite is 1,349,000 B. T. U., its conversion into gas shows an efficiency of 86per cent.
One hundred pounds of bituminous coal con verted into gas in a gas producer yields 116.66 pounds of carbonic oxide, equivalent to 504,554 B. T. U.; 32 pounds of volatile hydrocarbons, equivalent to 640,000 B. T. U.; and 2.5 pounds of hydrogen, equivalent to 155,000 B. T. U.— a total of 1,299,554 B. T. U. The total energy per pound of gas is 3,484 B. T. U. As the total energy in 100 pounds of bituminous coal is 1,437, 500 B. T. U., its conversion into gas shows an efficiency of 90 per cent.
In view of the facts that the supply of natural gas is gradually failing, and that the most satisfactory method of using the heat from other fuels is to first convert it into gas, it is interesting to note that in the gasification of fuels having a high percentage of moisture, high percentages of carbonic acid and hydro gen occur in the gas. This is probably due to the fact that at a temperature of about F., water vapor oxidizes carbonic oxide to car bonic acid. Therefore, coke and charcoal, which have a low value as a direct-firing fuel, work more favorably in a gas producer, and yield more gas per pound than any other material. The approximate yield of gas per pound of different materials is as follows: coke or char coal, 104 cubic feet; anthracite, 85 cubic feet; bituminous coal, 75 cubic feet; lignite or brown coal, 55 cubic feet; peat, 45 cubic feet; wood 35 cubic feet.
Tests on The most important con clusions of the tests on fuel made by the gov ernment and by the laboratories of some of the principal universities are as follows: 1. Samples of coal from 17 States, tested in steam boiler plants, indicate that the high steaming quality of many of the American coals may be improved by washing.
2. Most of the American coals and lignites constitute an available source of power by util ization in gas producer plants.
3. Comparative tests made by the govern ment on 14 bituminous coals from nine States, indicate that when these coals are used in a gas producer plant, their power efficiency is two and one-half times greater than when they are directly fired in a steam boiler plant.
4. Some of the lignites found in undeveloped but extensive deposits in the Dakotas and Texas, show very high power producing qualities when gasified in the gas producer and used in the gas engine.
5. Some of the American coals, and the stock produced in mining them can be briquetted on a commercial basis.
6. Under these conditions of attainable fuel economy, it is merely a question of time when the gas engine will supersede any possible type of steam motor.
For relevant information consult articles un der the title GAS; GAS ENGINE; GASES, LAWS OF; and GAS PRODUCER.
Bibliography.— Bjorling, P. R, and Patent Fuel' (New York 1909) ; Booth, W. H., 'Liquid Fuel and Its Combustion' (West minster 1903) ; Brame, J. S. S., 'Fuel: Solid, Liquid and Gaseous' (New York 1914) ; Brislese F. J., An Introduction to the Study of Fuel' (New York 1912) ; Coste, I. H., and Andrews, E. R., 'Fuel, Gaseous Liquid and Solid' (London 1914) ; Lewes, V. B., 'Liquid and Gaseous Fuels' (London 1907) ; Poole, H., The Calorific Power of Fuels' (New York 1907) ; White, A. H., 'Technical Gas and Fuel Analysis' (New York 1913) ; United States Bureau of Mines Bulletin 23, 'Steaming Tests of Coal' (Washington 1908).