Study on the Optimal Running Temperature of Circulating Fluidized Bed Boiler Burning Fujian Anthracite

摘要

There is a contradiction in selecting the running temperature for CFB boilers burning Fujian anthracite, in order to simultaneously satisfy the requirement of efficient combustion and high desulfurization efficiency. Based on numerical simulation and industrial experiments, the effect of the running temperature on the carbon content in fly ash and the desulfurization efficiency were analyzed for two types of CFB boilers with different capacities. It is found that, with the rise of running temperature, both decrease quasi-linearly. For the 75 t/h CFB boiler, when the running temperature is lower than 950°C, the carbon content in fly ash is very high, causing a low burnout efficiency; maintaining the running temperature at 1000°C is favorable for the fine char to be burned out, however, continuous raise becomes almost useless. For 440 t/h CFB boiler, a higher burnout rate of the fine char particles can be obtained when the running temperature is kept at about 950°C, and further increase brings no evident benefit either. For the 75 t/h and 440 t/h CFB boilers burning Fujian anthracite, considering both the boiler efficiency and the combustion desulfurization efficiency, the optimal running temperature should be respectively about 980°C and 950°C.