300MW循环流化床锅炉屏式过热器传热特性及壁温研究

Study on the Heat Transfer Characteristic and Wall Temperature of Platen Superheater in a 300 MW CFB Boiler

建立了循环流化床锅炉屏式过热器传热模型,采用分区段方法计算了受热面管子在锅炉3种典型负荷下,管内工质温度和管壁金属温度的沿程分布特性;利用实炉运行数据研究了锅炉在不同负荷下屏式过热器传热系数的变化规律,分析了低负荷下循环流化床锅炉屏式过热器超温的原因。结果表明:循环流化床锅炉屏式过热器热负荷较均匀,管壁温度没有明显的突升情况,最高管壁温度出现在75%BMCR(锅炉最大连续蒸发量)负荷下。

A heat - transfer model of platen superheater of CFB boilers has been established in this paper. Based on heating calculation in sections for tubes on 3 typical loads, the steam temperature and the wall temperature distribution along the tubes have been presented. The change of heat - transfer coefficient for platen heating surface in different load is investigated according to the operation parameters. The cause of overheating of the platen superheater in low load is also analyzed in this paper. The results show that the heat transfer flux is well - distributed for platen superheater, but the highest wall temperature is appearing under the 75% BMCR load.