在深度调峰大背景下，针对循环流化床锅炉在低负荷运行时分离器入口烟道出现严重的积灰问题，影响锅炉正常运行。以某660 MW 循环流化床锅炉为研究对象，通过数值模拟的方法，分析了低负荷下锅炉内部流场的分布特征和飞灰沉积特性，并探究了入口速度和颗粒粒径对飞灰沉积的影响规律。模拟结果表明：烟气从炉膛流到分离器入口烟道过程中，在入口烟道底部会产生一个涡流区；小粒径的飞灰更易沉积在涡流区，而中大粒径飞灰更易沉积在烟道后半部分；粒径分布相同条件下，飞灰沉积率随着入口速度的增大而减小，且当入口速度大于1.95 m/s，沉积有较为明显的改善；飞灰粒径越大，沉积率越大，当粒径超过80μm，沉积率呈指数级增长。

In the context of deep peak shaving, there is a serious problem of ash accumulation in the inlet flue of the separator when the circulating fluidized bed boiler is running at low load, which affects the normal operation of the boiler. Taking a 660 MW circulating fluidized bed boiler as the research object, the distribution characteristics of the internal flow field and fly ash deposition characteristics of the boiler under low load were analyzed by numerical simulation, and the influence of inlet velocity and particle size on fly ash deposition was explored. The simulation results show that when the flue gas flows from the furnace to the inlet flue gas of the separator, a vortex zone will be generated at the bottom of the inlet flue. Fly ash with small particle size is more likely to be deposited in the vortex area, while fly ash with medium and large particle size is more likely to be deposited in the second half of the flue. Under the same particle size distribution, the fly ash deposition rate decreases with the increase of inlet velocity, and when the inlet velocity is greater than 1.95 m/s, the deposition rate is significantly improved. The larger the particle size of fly ash, the greater the deposition rate, and when the particle size exceeds 80 μm, the deposition rate increases exponentially.

山西省重点研发计划项目（201903D321075）