Abstract: 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.

Abstract: A poke hole closure assembly for a gas producer which minimizes the escape of noxious or volatile gas from the producer during a poking operation. The closure includes a block having an aperture therethrough which communicates with a poke hole in a gas producer. A closure plate is hinged to the block to block the aperture and pole hole during normal operating conditions, but is openable to enable a poker to be inserted therethrough to check the fire bed. An inert gas is delivered to a conical nozzle in the aparture to direct the gas into the poke hole, to thereby block the outward passage of noxious or volatile gas from the poke hole when the closure plate is opened. The flow of the inert gas is controlled by a valve which is opened to allow flow upon opening of the closure and is closed to block flow when the closure is sealed.

Abstract: A method of educting oil from fine, high carbon oil shales is disclosed. The method includes the steps of providing a burden of oil bearing shale having a high fixed carbon content and charging the shale in the traveling grate machine, preferably a circular traveling grate machine. The burden is moved in a horizontal plane into a retorting zone, where the shale is heated to an oil-educating temperature of at least 800 degrees F. Oil and a medium BTU gas is educted from the burden, and the burden is then moved to a gasifying zone, where steam and air are downdrafted through the burden to raise the temperature of the burden to a temperature in excess of 1800 degrees F. Such a temperature converts substantial amounts of residual carbon in the burden to carbonaceous gases, and promotes substantial agglomeration or clinkering of the spent shale to enable a separation recyling process. The spent shale is cooled and the spent agglomerated shale is discharged from the machine.