GB651370A - Method of producing fuel gases - Google Patents

Abstract

651,370. Gas-producers. STANDARD OIL DEVELOPMENT CO. Sept. 22, 1948, No. 24833. Convention date, Dec. 29, 1947. [Class 55(i)] Fuel gases of high heating value are produced by passing a gas containing carbonmonoxide and hydrogen through a dense fluidized mass of solid carbonaceous material whereby, under conditions of high temperature and pressure, the hydrogen reacts with the carbonaceous material and/ or the carbon-monoxide, to produce gaseous hydrocarbons. As shown, preheated carbonaceous material is fed from a hopper to the top of a chamber 10 which is divided into zones A, B, C by perforated grids 14, 16, the material gravitating from zone to zone through passages formed by vertical baffles 18, 20. The water-gas producing zone C is provided with a conical distributer 12 connected to a supply line 5 for steam preheated to 500‹-1000‹F., the air needed to maintain the required temperature (1600‹-2000‹F.) in the zone C being admitted with the steam. Heat necessary for the gasification is provided also by hot solids supplied from a combustion chamber 30 through the pipe 32, the chamber 30 being applied with residual carbonaceous material from the zone C through the pipes 22, 26, the fluidizing air admitted to the pipe 26 being preheated to 600‹-800‹F. and the temperature in the chamber 30 being maintained at about 100‹-200‹F. higher than the temperature in zone C. About 40-50 lbs. of hot solids are passed to the zone C from the chamber 30, for each pound of fresh carbonaceous feed. The water gas from the zone C, at high temperature, passes upwardly through the zone B in which a substantial proportion of the hydrogen is converted into methane. The temperature in the zone B (1400‹-1600‹F.) is lower than that in the zone C in spite of the exothermic reaction, the temperature of the solids entering the zone B from the zone A being substantially below that of the water gas. The gas with methane content. passes into zone A where further methane may be produced if the preheat of the fresh carbonaceous material is at the level of 900 -1600‹F., or the zone A may be used only for drying and preheating the fresh carbonaceous material passing to the zone B, in which case an external preheat of 500‹-700‹F. is preferred. A gas-solids separator 34 is provided in the off-take 38, and the off-take gas and excess solids'withdrawn through the pipe 40 may be used for preheating process solids or gases. Temperature control in zones A, B may be effected by heat-exchange coils 42, 44 and/ or by steam injection through pipes 46, 48. Thus ignition may serve to convert some of the carbon-monoxide into carbon-dioxide and hydrogen, the hydrogen being subsequently converted to methane. The pressure in the chamber 10 is from 5 to 50 atmospheres. If coal is fed into the zone A, it is carbonized, but if it is undesirable to produce tar at this point, a separate carbonization zone is added. Superheated steam and some air is supplied to the carbonization zone which operates at 900‹- 1000‹F.. the gaseous carbonization products being collected as such, or admitted to the gasification zone C where the tars are converted into carbon-monoxide and hydrogen. The solids from the carbonization zone are admitted to the zone A. The zones A, B. C may be arranged in separate casings which are connected by pipes, feed hoppers or pressurized mechanical conveyers.