600 MW超临界循环流化床锅炉外置床壁温特性分析

为了防止首台600 MW超临界循环流化床（circulating fluidized bed,CFB）锅炉外置床受热面发生壁温超温现象,在受热面管壁上安装了温度测点.对锅炉额定负荷下的外置床受热面管壁温度进行了测量,得到了外置床受热面管壁温度的分布特性,在测量数据的基础上分析了外置床受热面的运行安全性.研究结果表明,外置床内的高温再热器管壁温度呈中间高、两边低的马鞍形分布,而中温过热器Ⅰ及中温过热器Ⅱ管壁温度分布比较均匀;外置床受热面管壁温度均在所使用材料的最高允许温度之内,并有足够的温度裕度.最后,针对外置床运行过程中的管壁温度报警值的设定方法提出了技术建议.

Tube Wall Temperature Characteristic of External Heat Exchanger in 600 MW Supercritical CFB Boiler

In order to prevent the overtemperature of heating surface in external heat exchanger （EHE） of the first 600 MW supercritical circulating fluidized bed （ CFB ） boiler, temperature measuring points were installed on the heating surface tube. The tube wall temperature of EHE was measured under boiler rated load, and its distribution characteristics were obtained. Then, the operation safety of EHE heating surface was analyzed based on measured data. The research results show that the tube wall temperature of high temperature reheater in EHE is saddle distribution which is high in the middle and low on both sides; while the tube wall temperature distribution is more uniform for medium temperature superheater Ⅰ and medium temperature superheater Ⅱ. The tube wall temperature of EHE heating surface is within the maximum allowable temperature of the material used, and has enough margins. Finally, this paper proposed some technical suggestions on the setting method of alarm value for tube wall temperature in EHE operation.