The COGAS Project-One Method of Coal to Gas Conversion

Coal gasification processes are characterized by a series of general process steps consisting of coal preparation, reaction with steam (or steam and hydrogen), gas purification, shift, and methane synthesis. The chemical reactions involved are simple, but the equilibrium relationships are reasonably complex. A number of these processes have reached the pilot plant stage with two pilot plants in operation. The relative economics can be estimated from heat and carbon utilization efficiencies. The COGAS process development is a privately financed program directed toward production of oil as well as gas from coal using low pressure in the coal conversion steps. This process, which can be applied to a wide variety of coals, consists of pyrolysis of the coal to extract the volatile matter and yield a low volatile char, reaction of the char with steam in a unique gasification step, followed by processing of the oil and gas to product quality. The efficiency of the COGAS process appears to compare favorably with the other processes under development, and its use of low-pressure fluidized-bed processes is expected to have operating advantages. A pilot plant for the COGAS process is under construction.