692.    DENT, F. J., BLACKBURN, W. H., AND MILLETT, H. C.  Investigation of the Use of Oxygen and High Pressure in Gasification.  II.  Synthesis of Gaseous Hydrocarbons at High Pressure.  Rept. 41, Joint Research Committee, Institution of Gas Engineers and University of Leeds; Inst. Gas Eng. Commun. and Repts., Copyright Pub. 167/56, 1937, 58 pp.; Trans. Inst. Gas Eng., vol. 87, 1937-1938, p. 231; Gas Jour., vol. 220, 1938, pp. 470, 473-475, 658-659; Gas World, vol. 107, 1938, pp. 424-425, 545-546; Chem. Abs., vol. 32, 1938, p. 6435.

      Preliminary experiments showed that it was possible to gasify all types of bituminous coals and lignite in steam under pressure with synthesis of hydrocarbons in the fuel bed and the production of a gas of calorific value high enough for general supply.  Various types of fuels were heated to 800° (1 ½-2 ¾ hr.) in a stream of H₂ or gas contg. H₂ at 1-100 atm. pressure and held for 1 ½ hr.; similar tests in N₂ were run for comparison.  Results with a coke prepared at 450°-500° from Yorkshire coal are typical.  In N₂, yields at atm. pressure were H_2, 23.0; CH₄, 14.7; and total gaseous hydrocarbons 16.3 therms per ton of coke.  In H₂, yields at atm. pressure were H₂ 1.3 and gaseous hydrocarbons 33.8 therms.  At 5 atm., yields of gaseous hydrocarbons were 92.1 therms; at 10 atm., 132.9 therms; at 25 atm., 202.5 therms; at 50 atm., 276.0 therms; and at 100 atm., 311.2 therms.  CH₄till was being formed at the end of the tests.  At 50 and 100 atm., tar yields increased.  Maximum calorific value of outgoing gas in B.t.u. per cu. ft. was 345 at 1 atm., 429 at 5 atm., 500 at 10 atm., 589 at 25 atm., 719 at 50 atm., and 914 at 100 atm.  Calorific value increased with increasing rate of heating or decreasing rate of H₂ supply, although there was an accompanying decrease in yield of hydrocarbons.  H₂ absorption, in therms per ton, was 32.9 at 5 atm., 60.8 at 10, 107.7 at 25, 153.5 at 50, and 193.5 at 100.  The coke contained 19.8% volatile matter, but % losses in weight were 18.6 at 1 atm., 27.7 at 5, 34.9 at 10, 44.6 at 25, 62.4 at 50, and 72.0 at 100.  At low pressure, hydrogenation was most rapid at 500°-550°; at higher pressure, 700°-750°.  These are temperatures related to thermal decomposition of coke; hence H₂ merely modifies the course of the decomposition.  The thermal yields of gaseous hydrocarbons were not reduced by substitution of CO-H₂ mixtures for H₂ if the rate of supply and pressure were increased to allow for lower H₂ in the mixture; CO dilution reduced the calorific value of gas.