PULVERIZED COAL FIRED BOILER WITH WALL-ATTACHMENT SECONDARY AIR AND GRID OVERFIRE AIR

摘要

A pulverized coal fired boiler with wall-attachment secondary air and grid overfire air. Main combustors (4) having primary air nozzles (6), secondary air nozzles (7), and close coupled overfire air nozzles (5) arranged at interval along a height direction of a hearth (1) are disposed at four corners of the hearth (1). A bidirectional wall-attachment secondary air nozzle (11) and a one-way wall-attachment secondary air nozzle (10) are arranged from bottom to top in a main combustion area (111) where the main combustor (4) is located. A one-way wall-attachment secondary air nozzle (9) is provided in a reduction area (112) between the main combustor (4) and a top overfire air nozzle. A grid overfire air nozzle (8) is provided in a burn-off area (113) where overfire air is located. The pulverized coal fired boiler with wall-attachment secondary air and grid overfire air reduces the amount of NO generated in the hearth (1), improves the reduction rate of NO along the flame, and improves the burn-off rate of the coke, so that only little unburned coke enters the burn-off area (113). Therefore, slagging on a water wall (2) is reduced, and ultra-low NOx emission is achieved while the combustion efficiency is not reduced, slags are not agglomerated in the hearth (1), and the gas temperature deviation is small.