Pulverized coal burner and pulverized coal boiler having it

摘要

A pulverized coal burner and a pulverized coal boiler having it are provided. The pulverized coal burner comprises a primary air cylinder (111) and a pulverized coal concentration device (112). The pulverized coal concentration device (112) can make the concentration of the pulverized coal flow gradually decrease from inside to outside along the radial direction, with respect to an axial line (100) of the primary air cylinder (111). The pulverized coal burner further comprises a pulverized coal separation cylinder (113) and a pulverized coal guiding cylinder (114) located downstream of the pulverized coal concentration device (112), wherein the back end of the pulverized coal separation cylinder (113) is connected with the front end of the pulverized coal guiding cylinder (114). The outlet of the pulverized coal guiding cylinder (114) has a conical expansion corner (1141). The pulverized coal burner further comprises a divergent nozzle (115) which is connected with the back end of the primary air cylinder (111) and whose sectional area gradually increases along the flow direction of the pulverized coal flow. The expansion angle (γ) of the divergent nozzle (115) is not smaller than the expansion angle (β) of the pulverized coal guiding cylinder (114). The amount of generation of nitrogen oxides is reduced, as the rich pulverized coal flow and lean pulverized coal flow are separately burnt in the pulverized coal burner. The heating area of the pulverized coal flow is increased, and the slagging of the water-cooled wall near the outlet of burner is avoided.