Fluid Bed Catalytic Oxidation: An Underdeveloped Hazardous Waste Disposal Technology

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Abstract
Fluid bed incinerators have been used to dispose of a wide variety of hazardous wastes including refinery waste streams, surplus explosives, PCB-contaminated transformer oil and oxychlorination process wastes. Both inert and catalytic solids have been employed separately and in mixed beds or sequential reactors. However, in most catalytic processes, the nature of the catalyst and the process operating conditions are proprietary. In this paper, the catalytic oxidation kinetics of three chlorinated hydrocarbons are determined in an externally pumped recycle reactor with a commercially available chromia on alumina catalyst. Conversion of the chlorocarbon species in the reactor effluent are monitored by gas chromatography for temperatures in the range 350 to 550°C. Regression of the measured catalytic oxidation rates yields rate expressions which are first order in the chlorocarbon concentration, between zero and first order in oxygen concentration and exhibit some inhibition by water. Some catalyst poisoning by halogen containing species is observed. However, the poisoning phenomena can be minimized by control of the H/Cl ratio in the mixed waste feed stream.