Mcdowell-Wellman Company

John C Sheppard

Thomas E Ban

William H Marlowe

A process is disclosed for gasifying pelletized coal to produce a low Btu gas containing large amounts of hydrogen and carbon monoxide. Advantageously, the process is carried out on a circular traveling grate machine on a continuous basis. A horizontally moving, quiescent, gas-permeable bed of coal is formed by depositing at least one layer of a sized recycle charge of coal and at least one layer of fresh coal. To initiate an oxidizing reaction zone, the surface of one of the layers is ignited and the zone travels as a wave downwardly into the layer and upwardly into any superposed layer. Air and steam or air and carbon dioxide are either updrafted or downdrafted through the bed to control combustion. The coal is reduced in zones ahead of the advancing zone or zones of oxidation, and the reactions are terminated before the oxidation zone reaches both outermost surfaces of the bed to minimize the formation of carbon dioxide. Unreacted coal is separated from fine ash and is used as the recycle feed.

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Cleveland, OH, United States of America

John C Sheppard