Patent ID: 7661376
Filing Date: 2010-02-16
Classification: D21C,F22B,F23G,F23M,Y02E,Y02P

Abstract:
1. A spent liquor recovery boiler system comprising: a boiler further comprising a water or steam circulation system having superheaters and a furnace for recovering energy and chemicals from spent liquor combusted in the furnace; walls of the boiler further comprising a plurality of water cooled tubes in fluid communication with the water or steam circulation system; at least one cavity separate from the boiler, said cavity having cavity walls formed of water cooled tubes in fluid communication with the water cooled tubes in at least one of the walls of the boiler and the superheaters of the water or steam circulation system of the boiler, wherein at least a portion of the water cooled tubes of the cavity walls is formed of the water cooled tubes of a front wall of the boiler; a fuel combustor arranged in the at least one cavity; at least one outlet of the cavity for discharging combustion gases from the cavity to the boiler at an elevation below the superheaters of the boiler, wherein said outlet of the cavity is opposite a bullnose section of a rear wall of the boiler and the outlet discharges combustion gases from the at least one cavity immediately upstream of the superheaters of the boiler, and an interior of the at least one cavity having a cavity heat exchanger for superheating steam generated by superheaters in the boiler, wherein the cavity heat exchanger is below the fuel combustor and above the at least one outlet of the cavity and the cavity heat exchanger receives steam from at least one of the superheaters in the boiler.