Abstract: Coal devolatized and partially gasified in a travelling grate reactor is dropped into a shaft furnace to form a downwardly moving stack which moves then downwardly to and through a fixed bed gasifier, wherein it is burned to ash. A gas stream from the travelling grate reactor is down-drafted through the shaft furnace and a gas stream is up-drafted through the fixed bed gasifier, and the two streams combined are drawn through a heat exchanger and fed to a gas burner, combustion air for the gas burner being heated in the heat exchanger.

Abstract: Coal is processed first through a moving bed reactor and then through a fixed bed reactor. Hot carbonized coal char is fed from the first stage reactor to the second stage reactor via a lock hopper and gas is taken off from the reactors either in separate streams or in a common stream.

Abstract: Vertically elongate pockets are defined between fixed and horizontally movable vertical refractory walls. When the bottom of the pocket is closed, coal dropped into the pocket from above is compressed between the fixed and movable walls and heated to coking temperature by hot gases in vertical flues extending through the refractory walls. When coked, the moveable wall recedes and the coke therein drops into a shaft furnace below, where devolatilization is complete and the coke is quenched in an inert gas atmosphere, which is totally enclosed to prevent air pollution.

Abstract: Continuously flowing solid material, such as municipal waste, is pretreated in an air-starved hot moving grate carbonizer furnace to drive off low temperature volatiles, and then further devolatized in a shaft furnace wherein limited amounts of air are let into a downwardly moving stack of the precarbonized material at a plurality of locations spaced sufficiently apart as to preclude formation of hot spots, i.e., localized regions of intense reaction, such as would cause clinkers to be formed. Low Btu gas is exhausted from the pretreatment carbonizer and shaft furnace and sterile ash residue is discharged from the bottom of the shaft furnace.

Abstract: Solid municipal waste refuse is pre-treated by partial burning in a moving grate hot carbonizer furnace and then further burned on a reciprocating step-grate stoker in the same furnace chamber. Limited amounts of air are fed to the waste through the grates to avoid the formation of hot spots in the burning material, thereby preventing the formation of clinkers and restricting the burning of volatile matter in the refuse. Hot low-Btu gas exhausted from the furnace chamber is burned in a boiler.