GB665781A - An improved manufacture of fuel gas - Google Patents

Abstract

665,781. Generating and enriching water gas; gaseous mixtures. ARNOLD, J. C., (Standard Oil Development Co.). July 12, 1950 [July 21, 1949], No. 19258/49. Classes 55 (i) and 55 (ii). Fuel gases of high thermal value are continuously generated by contacting water gas in a fluidized bed at high temperature and pressure, with powdered carbonaceous material to which has been added an iron oxide catalyst, methane being formed in the bed by combination of a proportion of the carbon monoxide and hydrogen in the water gas, the latter being generated by gasifying the powdered carbonaceous material from the methane synthesis zone in the form of a fluidized bed in a second zone by a gasifying agent including steam. The apparatus consists of a methane synthesis chamber 1 connected to a water gas generating chamber 2 by a gas transfer pipe 9 and coke transfer line 5. Finely ground coal or coke with an admixture of from 0.1 to 5 per cent of an iron ore catalyst, is fed to chamber 1 from a hopper 3 which can be pressurized to 100 to 600 pounds per square inch, the pressure in chambers 1 and 2. The material is fluidized at from 1100- 1300‹ F. by water gas generated in chamber 2 and flowing up through pipe 9, the water gas, with an increased content of methane, discharging through line 15. If coal is the raw material, carbonization occurs in chamber 1, the distilled volatile matter mixing with the outlet gas. Coke is withdrawn through line 5 and passed into chamber 2 where it is converted into water gas by admission of fluidizing steam from a line 7. To supply the heat requirements, oxygen for partial combustion is admitted through a line 8. Ash is withdrawn from chamber 2 through a line 10, a portion being recirculated through line 11 to be mixed with the raw fuel since it still contains the catalyst. Instead of using oxygen, the heat required for the water gas reaction may be supplied by withdrawing coke from chamber 1, partially burning it in a separate combuster and returning the thus heated material to chamber 2, Fig. 2 (not shown). In an example, a water gas composed of 45 per cent carbon monoxide and 55 per cent hydrogen was passed through a fluidized bed of coke containing 2.2 per cent of hematite, at 250 pounds per square inch and 1200‹ F. The product gas contained 10.2 per cent carbon dioxide, 36.8 per cent carbon monoxide, 36.8 per cent hydrogen and 16.2 per cent methane.