GB672500A - Improvements in or relating to the desulfurization of gaseous mixtures particularly synthesis gases - Google Patents

Abstract

672,500. Gas-purifying process. STANDARD OIL DEVELOPMENT CO. July 6, 1950 [March 23, 1950], No. 16946/50. Class 55 (ii). Sulphur compounds in water gas produced by gasifying solid carbonaceous materials with steam, are removed by bringing the gas into contact with a highly absorptive char of high surface area which has been withdrawn from the gasification zone. In the apparatus shown, finely-divided coal is fed from a hopper 1 into a first stage generator 5 and formed into a dense bed fluidized by a mixture of steam and oxygen admitted through lines 3 and 4. Water gas discharges through lines 10 and 11. The coke or char remains in generator 5 until its carbon content is between 45 and 75 per cent, when.its surface area is found to be a maximum, usually exceeding 500 square metres per gram. It is then withdrawn through lines 12 and 20 and is carried forward by the made water-gas from line 11, through a heat-exchanger 21, where the temperature of the suspension is lowered to between 75‹ and 400‹ F., to a desulphurizer 23, 1 to 2 per cent of air being added to the suspension through a line 22. A fluidized bed of the char is maintained in chamber 23, the organic sulphur compounds in the gas being adsorbed by the char and the H 2 S being oxidized by the air with the formation of free sulphur which deposits on the char. A cooling coil 34 maintains the bed at the correct temperature. Purified gas is led off through a line 24 and the sulphurized char through line 25, an air current from line 27 fluidizing the char in a regenerator vessel 28, so that the sulphur burns to SO 2 which discharges through line 29. The cleaned char leaves vessel 28 by line 30 and is taken up by a steam-oxygen mixture and fluidized in a second stage generator 16, the water-gas produced being added to that from generator 5, whilst ash is discharged through a line 19. If more char is produced in generator 5 than is required for desulphurization, it can be fed direct to generator 16 via line 14.