W-STAGED FLAME BOILER FOR MULTI-STAGE COMBUSTION WITH MULTI-EJECTION AND ITS METHOD THEREOF

摘要

A method for a flame boiler with multi-stage combustion with multi-ejection, includes the steps of ejecting inner and outer secondary air flows with speed of 35-65 m/s to guide a fuel-rich pulverized coal flow with speed of 10-20 m/s into a lower chamber to provide first and second combustion stages, ejecting lower secondary air flows with speed of 35-65 m/s into the lower chamber to further guide the pulverized coal so as to provide a third combustion stage. The system includes a lower chamber, an upper chamber, a combustion chamber, fuel-rich pulverized coal flow nozzles, fuel-lean pulverized coal flow nozzles respectively provided at the front and rear boiler arches, and lower secondary air nozzles provided at the front and rear water cooled walls. The combustion of the pulverized coal flow with W-shaped flowing path within the boiler is adapted to reduce NO_x emission and minimize the content of combustible substance in ash.