300MW循环流化床锅炉超温问题分析及解决

Analysis and Solutions of Overheating Problem in a 300 MW Circulating Fluidized Bed Boiler

某自主研发生产的300MW循环流化床(CFB)锅炉在升负荷过程中出现尾部低温过热器、低温再热器管壁超温现象,根据CFB锅炉炉内的传热机理,分析了超温主要原因是锅炉床料太粗,造成炉膛稀相区的固体颗粒浓度小、炉膛传热系数小而使炉内受热面吸热量比例偏少,进而造成尾部低温过热器、低温再热器吸热量偏大而管子超温。通过将炉内大颗粒外排、补充筛分过的较细床料和石灰石等主要措施,完全消除了超温现象,保证了锅炉的安全运行。

Overheating problem of low temperature superheater and reheater during the course of load increasing in a self-developed 300 MW Circulating Fluidized Bed（CFB）Boiler is introduced. According to the mechanism of heat transfer in CFB boiler,reasons of overheating are analyzed. Coarse bed material led to lower concentration of particles in the furnace dilute region and lower heat transfer coefficient in the furnace,which makes heating surfaces in the furnace absorb less heat and lead to overheating of low temperature superheater and reheater installed in the back-end ductwork. By discharging coarse bed material, adding small bed material be sieved and limestone particles into the furnace etc., overheating problem is solved completely,and safety operation of the boiler is guaranteed.