Steam generator having external fluidized bed combustion means

Claim 1

A steam generator having a feedwater inlet and superheated steam outlet and serially connected, coolant containing heat absorption circuits in-between, a multiplicity of detached fluidized bed combustors structurally and spacially set apart, the combustion process being completed within said combustors, said combustors each having means to control internal rate of combustion and to produce hot inert flue gas flow, first portion/s of said heat absorption circuits being disposed for in-bed cooling of said combustor fluidized beds, an integral encasement, said combustors external to said encasement, said encasement compartmentalized into discrete circuits for guiding flue gas flow through said encasement, said discrete circuits each receiving flue gas effluent from only a portion of said combustors directly through conduit means, second portion/s of said heat absorption circuits disposed within said encasement and adapted to recover heat from said flue gas flow, first segments of said second portion/s wherein the coolant is in the superheat vapor phase range, said first segments consisting of multiple heat exchange platens, coolant flowing serially through individual platen circuits and parallelly through said multiple heat exchange platens, said platens of said first segments disposed within the hot inlet end of said discrete circuits and distributed so that more heat exchange surface of one of said first segments is located in one of said discrete circuits than is located in another of said discrete circuits, said distribution of said platens for individual first segments between/among said discrete circuits providing the means for control of heat input distribution to said second portion/s of said serially connected heat absorption circuits in conjunction with selective setting of said rate of combustion for said combustors associated with individual elements of said discrete circuits.