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VAPOR-PHASE CRACKING AND WET OXIDATION AS POTENTIAL POLLUTANT CONTROL TECHNIQUES FOR COAL GASIFICATION
Citation:
McMichael, W., S. Gangwal, D. Green, AND F. Mixon. VAPOR-PHASE CRACKING AND WET OXIDATION AS POTENTIAL POLLUTANT CONTROL TECHNIQUES FOR COAL GASIFICATION. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/7-81/096.
Description:
The report gives results of an investigation of two techniques (hydrocracking of heavy organics in the raw gas prior to quency, and wet oxidation of the gasifier condensate) for pollutant control in coal gasification processes. Bench-scale experiments were used to determine rates of hydrocracking and wet oxidation as a function of process conditions and catalyst used. A microreactor system, capable of holding 1.0 cc of material to be screened for catalytic activity, was used in the hydrocracking studies. Benzene and alkylated benzene compounds were used as model compounds in determining the potential of various materials for cracking rates. Thiophene was used as a model compound for catalyst poisoning studies. Cracking rates were determined for coal-derived materials produced from bituminous and subbituminous coals and materials containing iron and nickel compounds. Experiments were carried out at 300 to 800 C and approximately atmospheric pressure. The most promising material screened was a triply-promoted iron oxide ammonia synthesis catalyst. It had the greatest activity at temperatures of practical interest for a control device and showed more sulfur resistance than the other materials screened. However, the catalyst was poisoned by sulfur: attempts to regenerate it by air oxidation were unsuccessful. Wet oxidation appeared competitive.