物料循环系统对循环流化床锅炉床温影响  

Effect of the Circulating Loop Performance on the Bed Temperature of a Circulating Fluidized Bed Boiler

作　　者：米学勤 刘雪敏[2] 吕俊复[2] 

机构地区：[1]燕山石化动力厂,北京100728 [2]清华大学热科学与动力工程教育部重点实验室,北京100084

出　　处：《锅炉技术》2013年第5期27-30,52,共5页Boiler Technology

基　　金：国家"十二五"科技支撑计划项目(2012BAA02B01)

摘　　要：循环流化床(CFB)锅炉在燃用石油焦方面具有优势。在全烧石油焦时CFB锅炉效率可达93%,CO低于60 mg/Nm^3,NO_x排放在20 mg/Nm^3以内,这得益于石油焦的高含碳量和低氮含量,但床温和过量空气系数要严格控制。提高煤的掺烧比例亦即燃料灰分增加能够提高炉膛物料浓度,在相同热输入条件下床温下降。理论计算发现,物料浓度增加了20%将导致换热系数上升约5%,对应地床温下降25℃左右,这与实际是一致的。根据理论分析,提出了减小循环量降低固体物料浓度可以提高床温的建议,该设想得到实践验证。coke. The Circulating CFB boiler The original emission fluidized bed （CFB） boiler is more advanced when the fuel is petroleum heat efficiency reaches 93 % with CO emission of less than 60 mg/Nma. of NOx is les than 20 mg/Nma due to its higher carbon content and lower N in it. However, Nox emission depends strongly on the bed temperature as well as the excess air coefficient. Increasing the ratio of coal in the petroleum coke blend leads to the average ash contend in the fuel increasing, which will causes the increasing of solid bulk density in the furnace. And the bed temperature decreases when the input heat remains same. The theoretical prediction showed that the solid bulk density increases 20% results in the heat transfer coefficient increasing about 5%, which means the bed temperature decreases about 25℃. This prediction agrees well with the practice. Based on the theoretical analysis, a solution to increase the bed temperature is suggested to decrease the solid circulating rate to reduce the solid suspension density in the furnace, which is confirmed by the operation.

关 键 词：循环流化床锅炉 物料循环 床温 影响 

分 类 号：TK229.66[动力工程及工程热物理—动力机械及工程]