关键词: 循环流化床锅炉, 二次风入口, 内部流场

Abstract: The inadequate depth of secondary air caused boiler insufficient oxygen in the furnace center and uneven flow in the Circulating Fluidized Bed (CFB). The uneven flow between the gas and solid phases not only increased the abrasion on the cooling wall but also reduced the combustion efficiency，restricting the development of large-scale CFB boiler. Aiming at the injection of secondary air in CFB boiler，the design of secondary air inlet for a 150 MW CFB boiler was improved，using Eulerian multiphase model to investigate the flow field in the furnace. The results showed that the internal gas-solid flow field was more even with new inlet and anoxic zone in the center was eliminated， with a great improvement of combustion efficiency and reduction of the abrasion on the cooling wall. The improved design also allowed secondary air enter the furnace with lower momentum which reduced the energy consumption energy cost.

Key words: CFB boiler, secondary air inlet, internal flow field