Abstract: A shaft furnace is provided for gasifying granular fuels in a fluidized bed. Such a furnace comprises a gasification zone containing the fluidized fuel bed and an overlying gas cooling zone having surfaces cooled by the tube surfaces of a radiation tube boiler. By providing such a gas cooling zone with a cross-sectional area substantially greater than that of the gasification zone, the gas effluent is cooled in such a manner that residues entrained in the effluent do not sinter onto the surfaces of the equipment in the subsequent path of the effluent.

Abstract: A single reactor is used for gasifying solid fuels of a wide range of particle sizes without first comminuting the particles to a common size. The larger particles are gasified on a fixed bed, and the smaller ones are gasified on a fluidized bed. In the reactor, the fluidized bed is arranged above the fixed bed and gases rising from the fixed bed help to fluidize the fluidized bed. In addition, a dust gasification region can be provided above the fluidized bed.