大型燃煤锅炉热偏差分析及防治方案

Analysis and prevention of thermal deviation of large coal-fired boiler

为解决大型燃煤锅炉运行中由于燃烧不均衡造成的受热面超温及水冷壁壁温、烟温、汽温偏差大等问题,首先,分析锅炉热偏差产生的原因及其给锅炉运行安全带来的危害;然后,基于一次风煤粉在线均衡控制系统,依据壁温、汽温偏差,调整二次风量分配的锅炉热偏差;最后,设计锅炉热偏差自动控制系统,并将该系统应用到国内某电厂1000 MW对冲燃烧锅炉以及其他多种锅炉上,验证该该系统的实用性和有效性。结果表明:该系统可使得各燃烧器风煤比均衡一致,实现燃烧器状态的精准测控,防控燃烧器燃烧偏差及局部燃烧恶化现象,消除燃烧热偏差导致的锅炉运行隐患。

This paper aimed to solve the problems of overheating of heating surface,large deviation of water wall temperature,smoke temperature and steam temperature caused by unbalanced combustion in the operation of large coal-fired boilers.First,the causes of boiler thermal deviation and its harm to boiler operation safety were analyzed,and then the general idea of boiler thermal deviation prevention was proposed based on primary air and pulverized coal online balance control system,wall temperature and steam temperature deviation,and adjusting secondary air volume distribution.Finally,the boiler thermal deviation automatic control system was designed and applied to a 1000 MW opposed firing boiler in a domestic power plant and other boilers to verify the practicability and effectiveness of the system.The results show that the system can make the air coal ratio of each burner balanced and consistent,realize the accurate measurement and control of the burner state,eliminate the combustion deviation and local combustion deterioration of the burner,and improve the hidden danger of boiler safe operation caused by combustion thermal deviation.