300MW富氧煤粉锅炉烟气冷却换热特性分析  

Influence on Flue Gas Compression System Operating Characteristics of Oxy-coal fired Boiler from Furnace Air Leakage

作　　者：高建强[1] 孙少东[1] 

机构地区：[1]华北电力大学能源动力与机械工程学院

出　　处：《电站系统工程》2015年第5期40-42,45,共4页Power System Engineering

基　　金：河北省自然科学基金项目(F2012502068)资助

摘　　要：富氧煤粉燃烧锅炉回收烟气在多级压缩和冷凝过程,其热物性参数的变化较为复杂,分析不同压力条件下烟气与冷却器对流受热面间的换热特性,对烟气冷却器的设计和运行优化有重要的意义。以某300 MW机组富氧煤粉燃烧锅炉烟气冷却器为研究对象,通过热力计算分析不同压力条件下烟气水蒸汽摩尔份额和烟气温度变化对对流受热面换热特性的影响,该过程充分考虑烟气的辐射放热计算。结果表明:当烟气的压力增大时,烟气的对流放热系数、辐射放热系数和凝结放热系数明显增大,总的放热系数增大,烟气冷却器对流受热面的换热能力增强;水蒸汽摩尔份额越少,烟气的对流放热系数、辐射放热系数和凝结放热系数越小,总的放热系数越小,烟气冷却器对流受热面的换热能力明显减弱;入口烟气温度升高使烟气的辐射放热系数增大。但是烟气的凝结放热系数明显减小,是使烟气总的放热系数减小的主要因素。In the 300MW oxy-coal fired boiler, the thermal physical parameters changes of the recoverable flue gas is much complex in the multistage compression and condensation process. It is significant for the flue gas cooler design and operation optimization to analyze heat transfer characteristics of the flue gas and cooler convection heating surface at different pressures. The flue gas cooler in a 300MW oxy-coal fired boiler unit was taken as an object of study. The impact of flue gas water vapor mole share and temperature change on the heat transfer characteristics of convective heating surface was analyzed by thermodynamic calculation under different pressures, in which the flue gas heat radiated calculations of was fully considered. The results showed that the convection coefficient, radiation coefficient and condensation coefficient of flue gas significantly increased with the rise of flue gas pressure. Thus, the heat capacity enhancement of flue gas cooler convection surface results from the increase of total heat transfer coefficient; the convection coefficient, radiation coefficient and condensation coefficient of flue gas significantly decreased with less water vapor mole share. Thus, the weaken heat capacity of flue gas cooler convection surface results from the decrease of total heat transfer coefficient; The increases of inlet flue gas temperature leads to the increase of the radiation coefficient. However, flue gas condensation coefficient is significantly decreased, which is the main factors of the total heat coefficient decrease.

关 键 词：富氧煤粉锅炉 烟气冷却器 不同压力 换热特性 

分 类 号：TK227[动力工程及工程热物理—动力机械及工程]