Abstract: A fluidized-bed system for feeding coal or a coal-limestone mixture into a fluidized bed combustor, a perforated horizontal distributor plate dividing the chamber into upper and lower chamber sections, means for feeding solid fuel particles into the upper chamber section, a source of high velocity gas connected to the lower chamber section and passing through the plate into the upper chamber section for entraining the particles, means for heating the high velocity gas before it is introduced into the upper chamber, an entrainment section defined by converging upper sides of said fuel feeding chamber, and a stream splitting section disposed above said entrainment section and connected to a plurality of pneumatic transport lines each penetrating the distributor plate of a fluidized bed combustor and terminating in an outlet feedport.

Abstract: A coal-dolomite mixture is ground into particle-sized bits and fed into a downward sloping duct beneath the distributor plate in a fluidized-bed combustor. High velocity air is introduced through ports spaced at intervals along the bottom of the duct, thereby entraining the mixture in an air stream. The air and entrained solid is guided upward into a slot-like chamber which passes through the distributor plate and opens into the fluidized bed a distance above the plate. Vanes in the duct and chamber and baffles above the chamber exit control the flow of the air and entrained solids so that the coal-dolomite mixture is evenly distributed throughout the fluidized bed. The distributor plate is covered with a layer of high temperature alumina stones graded in size, with the coarse stones in closest contact with the plate and the fine stones on top, thereby shielding the plate from the high temperatures of the combustion zone and preventing the weeping of hot and ash burning coal particles onto the plate.