Patent ID: 8622029
Filing Date: 2014-01-07
Classification: F23C,F23L

Abstract:
1. A circulating fluidized bed (CFB) boiler comprising: a CFB reaction chamber having side walls and a grid defining a floor at a lower end of the CFB reaction chamber for providing fluidizing gas into the CFB reaction chamber; a bubbling fluidized bed (BFB) located within a lower portion of the CFB reaction chamber and being bound by one or more of the side walls of the CFB reaction chamber, the floor of the CFB reaction chamber, and an enclosure wall formed by cooled tubes that extend upward from the floor of the CFB to a height of the BFB; at least one controllable in-bed heat exchanger (IBHX) immersed in the BFB, the IBHX comprising a heating surface and occupying part of the CFB reaction chamber floor; and at least one in-furnace secondary air conduit and nozzle defined by a plurality of the cooled tubes of the BFB enclosure wall, wherein the cooled tubes further extend from a top of the BFB enclosure wall across the width of the BFB to one of the side walls of the CFB reaction chamber, and wherein the plurality of the cooled tubes forms openings through which solids can fall into the BFB.