1000 MW机组锅炉空气预热器旁路余热利用系统节能效果分析  

Study on energy-saving effect of bypass waste heat utilization system of air preheater in a 1 000 MW unit boiler

作　　者：王春昌[1] 马剑民[1] 张宇博[1] 杨辉[1] WANG Chunchang;MA Jianmin;ZHANG Yubo;YANG Hui(Xi’an Thermal Power Research Institute Co.,Ltd.,Xi’an 710054,China)

机构地区：[1]西安热工研究院有限公司

出　　处：《热力发电》2019年第11期56-61,共6页Thermal Power Generation

摘　　要：目前,国内电站燃煤锅炉常用烟气余热利用技术中,主要典型系统有烟气冷却器系统、水媒式烟气-烟气冷却器(MGGH)系统、冷风加热器+烟气冷却器系统、冷风加热器+空气预热器旁路系统4种。本文重点分析了冷风加热器+空气预热器旁路系统及冷风加热器+烟气冷却器系统对锅炉入炉热量及锅炉热效率的影响,并分别从烟气侧与空气侧计算了其影响程度,在此基础上,对上述2种烟气余热利用系统的综合节能效果进行了对比计算。结果表明:冷风加热器+空气预热器旁路系统并非节能效果最优,在各种工况下,其节能效果均小于冷风加热器+烟气冷却器系统;在额定负荷设计工况下,冷风加热器+空气预热器旁路系统节能效果比冷风加热器+烟气冷却器系统低0.797 g/(kW·h)。其原因是该系统将可用于锅炉的能量品位最高的热量用于烟气余热利用系统,违反了能量梯级利用原则。At present,the commonly used flue gas waste heat utilization system in domestic coal-fired power plants mainly includes four typical kinds:the flue gas colder system,the water medium gas-gas cooler(MGGH)system,the cold air heater+flue gas cooler system,and the cold air heater+air preheater bypass system.The influence of the cold air heater+air preheater bypass system and the cold air heater+flue gas cooler system on the heat entering into the boiler and the thermal efficiency of the boiler is analyzed in this paper.Moreover,the influence degree is calculated,from both the flue gas side and the air side.On this basis,comprehensive energy conservation effects of the above two systems are calculated and compared.The result shows that,the cold air heater+air preheater bypass system is not the system with the best energy saving effect.Under various conditions,its energy conservation efficiency is lower than that of the coal air heater+flue gas cooler system.Under rated load design condition,the energy conservation efficiency of the cold air heater+air preheater bypass system is 0.797 g/(kW·h)lower than that of the coal air heater+flue gas cooler system.This is because the cold air heater+air preheater bypass system applies the heatwith the highest grade(which can be used in the boiler)to the flue gas waste heat utilization system,which violates the principle of energy cascade utilization.

关 键 词：空气预热器 余热利用 旁路烟气 热风温度 入炉热量 排烟温度 节能效果 

分 类 号：TK115[动力工程及工程热物理—热能工程]