453.    ---------------.[CHAFFEE, C. C., THOMPSON, O. F., KING, J. G., ATWELL, H. V., AND JONES, I. H.]  Metallgesellschaft-Lurgi.  Frankfurt am Main, Germany.  VII.  High-Pressure Gasification.  CIOS Rept. XXXI-23, 1945, pp. 29-42; TOM Reel 196; PB Rept. 12,624.

                  In the high-pressure gasification process developed by Lurgi, solid fuel, preferably weakly coking or non-coking bituminous and brown coals, is continuously gasified at from 20-30 atm. pressure with O2 and steam.  The coal need not be dry, but the water content should not exceed 25%.  Four plants had been built by Lurgi:  At Hirsdchfelde, 5 million m.3 gas/year; 2 at Böhlen, 150 million m.3; and at Brüx, 100 million m.3  The generator and its operation are described, operating results are presented, and directions are given for recovery of the liquid products.  Results are given for 3 kinds of fuel – 2 brown and 1 lean bituminous coal.  Composition of a typical purified city gas – CO2, 3.0; CnHm, 0.5; O2, 0.1; CO, 22.8; H2, 48.7; CH4, 22.6; N2, 2.3%; gas yield 760 m.3/ton; O2 requirement 0.15 m.3/m.3 gas (about one-half that required by Winkler generator); efficiency of fuel conversion, about 85.2%; cost 2.4 pf./m.3 with brown coal at 6.5 RM./ton.  In the making of synthesis gas a different procedure is followed.  It has been found that the actual pressure existing in the pressure generator influences the nature of the produced gas; at lower pressures less CH4 is formed in the presence of C. pressure displaces the CO:CO2 equilibrium in favor of CO2.  At low temperature also the equilibrium is further displaced in favor of a reduced formation of CO.  Since the required reduction of CO formation is not great, it is adequate to reduce the pressure from the usual 20 atm. to about 5-10 atm.  Practical tests have shown that a CO-H2 gas mixture suitable for the Fischer-Tropsch synthesis with Co-ThO2 catalyst can be prepared by the gasification of low-temperature bituminous coke when employing a pressure of about 8.5 atm. with both O2 and steam.  Under such conditions a crude gas of composition (CO2, 29.3; CO, 21.9; H2, 44.0; CH4, 3.3; N2, 1.5%) is obtained, which, after the CO2 is scrubbed out, yields a synthesis gas of composition:  CO2, 1.0; CO, 30.7; H2, 61.6; CH4, 4.6; N2, 2.1%.  Furthermore, by increasing the addition of steam in the pressure gasification, the formation of CO may be so reduced that a scrubbed gas containing 70-75% H2 and only 15% CO is produced suitable for NH3 synthesis or for hydrogenation.  In preparing synthesis gas of 1.2 H2:CO ratio to be used with the Fe catalyst, the procedure again is different.  An analysis of the various possibilities available for the solution of the problem has led to the conclusion that economically the most advantageous method for preparing the gas from brown coal is to employ O2 at a pressure of about 23.5 atm., and after scrubbing the gas to remove about 1/3 of the CO2 and some of the H2S.  The gas is heated to 145°, saturated with H2O, again preheated to 500°, and by partial combustion with O2 heated to 1,300°, in the absence of a catalyst to convert the CH4 content to CO and H2.  After scrubbing to remove CO2 the synthesis gas has the composition:  CO2, 2.0; CnHm, 0.2; CO, 42.2; H2, 50.7; CH4, 2.4; N2, 2.5%.  In this method of synthesis-gas production, 0.317 m.3 of O2 is consumed per m.3  A flow sheet with diagram of apparatus is appended.  O2 for the process is produced by the Linde-Fränkl method at a cost of 2.2-2.5 pf./N m.3 in units of 1,000-2,000 N m.3/hr. capacity and power consumption of 0.65-0.68 kw.-hr./N m.3

                  CHAKRAVARTY, J. N.  See abs. 1183.