STAGED COMBUSTION METHOD WITH MULTIPLE INJECTIONS AND W-SHAPED FLAME BOILER DEVICE FOR CARRYING OUT THE SAME

摘要

A staged combustion method with multiple injections and a W-shaped flame boiler device for carrying out the same are provided. The method includes: inner and outer secondary air with wind velocity of 35-65 m/s are stagedly injected, carrying dense pulverized coal with wind velocity of 10-20 m/s downwards, thereby a first-stage and second-stage combustion are achieved; under-arch secondary air with wind velocity of 35-65 m/s is injected from multiple under-arch secondary-air ports to the lower hearth, thereby a third-stage combustion is achieved. A W-shaped flame boiler device for carrying out the method includes dense pulverized coal flow nozzles (10), inner secondary air nozzles (11), lean pulverized coal flow nozzles (12) and outer secondary air nozzles (13) respectively arranged in the arch (3, 15) from the center (2-1) of the hearth to the front/ back water-cooled wall (2-2, 2-3) in turn, and multiple under-arch secondary air nozzles (14) arranged in the front and back walls of the lower hearth (1) in the width direction of the hearth. The W-shaped flame boiler device can substantially reduce the emission of NOx and decrease the content of fly ash combustible.