Abstract: A heat exchange flow passage 21 comprises a plurality of annular flow passages arranged in parallel to each other and also communicated to each other in the circumferential direction, a plurality of inflow ports and a plurality of outflow ports provided in the annular flow passage 24 at positions displaced from each other in the circumferential direction, and a plurality of communication pipes 25 each communicating the inflow port and the outflow port provided in different annular flow passages 24, 24. A fluid feed pipe 22 and a fluid discharge pipe 23 are communicated to this heat exchange flow passage 21 to form a heat exchanging apparatus.

Abstract: The invention relates to a method for combusting a dirty and/or difficult to burn fuel in a fluidized bed combustor. The fluidized bed and freeboard zone of the combustor are cooled by a non-intrusive counterflow cooling system which controls combustion temperatures and produces a clean, hot gas. The combustor is operated with many combinations of features including: low, in bed fuel injection; use of finely divided fuel; slug flow fluidization; and injection of lime or limestone to effect desulferization or raise the ash melting temperature, if desired.