CIRCULATING FLUIDIZED BED BOILER WITH AN AIR PREHEATER SYSTEM

摘要

A circulating fluidized bed boiler with an air preheater system,comprising a furnace for combusting particulate solid fuel with primary air injected to the furnace through a bottom grid and secondary air injected to the furnace through walls of the furnace; a flue gas channel connected to the furnace for discharging flue gas and particles entrained therewith from the furnace, a particle separator for separating particles from the flue gas;a return duct for returning separated particles from the particle separator to the furnace;and a fluidized bed heat exchange chamber for recovering heat from particles conducted therein from the furnace, the fluidized bed heat exchange chamber comprising inlet means for conducting particles from the furnace to the fluidized bed heat exchange chamber;outlet means for conducting particles from the fluidized bed heat exchange chamber back to the furnace;and means for injecting second fluidizing gas to the fluidized bed heat exchange chamber, wherein the air preheater system comprises a primary air preheater arranged in a first portion of the flue gas channel for preheating the primary air and secondary air and an air preheater for preheating the second fluidizing air arranged in a second portion of the flue gas channel, which second portion of the flue gas channel is connected in parallel with the first portion of the flue gas channel.