Abstract: A fluid bed combustor as well as a method of making same is disclosed. The combustor comprises a chamber containing a bed of relatively inert particles supported on a substantially horizontal distributor plate, a plurality of heat extractor tubes which pass upwardly through said plate in a substantially vertical direction, said tubes being distributed substantially uniformly over all or part of the plate surface so as to permit efficient heat extraction from the entire fluid bed volume, and means for supplying combustion gas through said plate to support combustion and to fluidize the bed.