INDUSTRIAL AND ENGINEERING CHEMISTRY
488
Vol. 19, No. 4
Hydrocarbons in Gas from the Low-Temperature Carbonization of Coal' By F. E. Frey and W. P. Yant PITTSBURGH EXPERIMENT STATION, U. S. BURBAUOF MINES,PITTSBURGH, PA.
HIS study was undertaken for the purpose of getting
yield under these conditions, except methane, must have more intimate information about the hydrocarbon been evolved, as a similar carbonization with steam entering constituents of coal gas and hence of its properties. a t 850" C. gave no higher a yield of these hydrocarbons. This information is of further interest from the standpoint Coal Used of the utilization of the hydrocarbons and for any light it may throw on the complicated mechanism of the thermal The coal carbonized vas a resinous, non-coking coal decomposition of coal. Schutz, Buschmann, and Wisse- from the Mesa Verda bed, mined near Salt Lake City, Utah, bach2 found n-butane, ethylene, propylene, ethylethylene, the same as that used in the previous work.4 symmetrical dimethylethylene, and 1,3-butadjene in the Fractionation Analysis of the Gas light oils of a primary tar. The relative amounts of ethylene, propylene, butylene, The possible gaseous hydrocarbons are limited in number and 1,3-butadiene in gas and those known have been produced by low-temperlisted in Table I. The boilature carbonization h a v e A gas produced by the low-temperature carbonizaing points, particularly of b e e n d e t e r m i n e d by tion of a resinous non-coking coal by internal applicathe simpler ones, depend Arnold.3 I n the present tion of heat with superheated steam was analyzed chiefly upon the number of s t u d y t h e percentage of with special attention to the gaseous hydrocarbons. carbon atoms per molecule .each gaseous hydrocarbon An analysis by fractional distillation of a small and are not much affected present in considerable sample of gas was supplemented by a study of the hyby differences in structure amount was determined. drocarbons condensed by liquid air from a considerable and unsaturation. On this volume of gas. account fractional distillaMethod of Producing the tion is especially useful in Gas Retort and Its their examination. Operation A sample of unscrubbed gas was analyzed, with the aid The carbonization was performed by a continuous method of fractional distillation, by a modification of the Shepherdwith internal application of heat by superheated steam. Porter method.6 The hydrocarbons were separated into The retort used was of vertical type designed by L. C . fractions containing 1,2, 3, and 4 carbon atoms per molecule. Karrick, formerly with the Bureau of Mines, for experi- The unsaturated hydrocarbons in each fraction were demental purposes, and described in detail in a previous re- termined by absorption in sulfuric acid containing silver port.4 Coal of "4 to 1-inch size mixed with an equal volume and nickel sulfates and of a concentration determined by of metallurgical coke was passed at a uniform rate down through a vertical carbonizing chamber, g,4 13.5 feet in Table I-Gaseous Hydrocarbons a n d Thefr Boiling P o i n t s height, 5 inches inside diameter a t the top, and 7 inches HYDROCARBON BOILING POINT AUTHORITYO a t the bottom. Superheated steam entered the chamber through manifold h at a temperature of 700" C. and passed c. Methane (CHI) up through the descending charge, and partly devolatilized Ethane ---164 84 (CH3. CHd it. No external heating was used above the point of steam Ethylene (CHz:CHn) 103 Acetylene (CH i CH) 82 (sublimes) entry, but the 3.5-foot section, i, of the chamber, through Propane (CH3CHzCHa) -- 45 48 (CH3CH:CHd which the partly devolatilized coal passed before being dis- Propylene Methylacetylene (CHaC i CH) - 2 3 . 5 Compt rend 140, charged, was heated externally to 700" c., measured inside 1031, (1905j' Propadiene (CHz:C:CHz) 32 Comfit rend 140, the wall, and some further devolatilizatjon brought about. io36 (1905j' The highest temperature noted was 725" C. The steam, Cyclopropane (CH?
