摘要
我国近年来投运的部分超临界机组锅炉存在排烟温度高于设计值的现象。对部分超临界机组锅炉省煤器与空气预热器设计参数进行了分析,表明随锅炉压力与给水温度的提高,锅炉尾部需回收的热量受到制粉系统所需干燥热量的制约。采用热量与质量平衡的计算方法,对燃用不同水分与挥发分的烟煤及贫煤的两台锅炉尾部热量与制粉干燥出力进行计算。结果表明,在给水温度提高的条件下,磨煤机出口控制温度偏低、省煤器出口烟气与给水温差偏大等因素是造成锅炉排烟温度偏高的主要原因,而省煤器出口水温的进一步提高则会加剧传热恶化。
The phenomenon of exhaust flue gas temperature being higher than the designed value exists in operation of some boilers for supercritical units put into service in recent years,the designed parameters of economizer and air preheater for some boilers of supercritical units have been analysed,it shows that the recoverable heat at the end of boiler and the heat required for drying in the coal pulverizing system were limited with increasing of the steam pressure and the feed-water temperature.By using the heat and mass balancing method,the recoverable heat at the end of boiler and the heat required for drying in coal pulverizing system have been calculated respectively for two boilers burning bituminous coal and lean coal with different water content and volatile matter content.The results of calculation show that the main causes resulting in high exhaust flue gas temperature are as follows：the controlled outlet temperature of the coal pulverizer is lower,the temperature difference between outlet flue gas and feed-water of the economizer is large etc,under condition of increasing the feed-water temperature,whereas further increasing the outlet water temperature of econimizer may intensify the deterioration of heat transfer.
出处
《热力发电》
CAS
北大核心
2010年第8期33-37,共5页
Thermal Power Generation
关键词
超临界机组
锅炉
排烟温度
给水温度
热量平衡
制粉干燥
supercritical parameter
boiler
exhaust flue gas temperature
feed-water temperature
heat balance
