电站锅炉烟气余热利用的热力学分析与优化设计原则  

Thermodynamic Analysis and Optimum Design Principles of the Heat Recovery of Utility Boilers' Flue Gas

作　　者：黄圣伟[1] 徐钢[1] 杨勇平[1] 刘超[1] 刘文毅[1] 杨志平[1] 

机构地区：[1]华北电力大学电站设备状态监测与控制教育部重点实验室,北京102206

出　　处：《现代电力》2013年第1期75-80,共6页Modern Electric Power

基　　金：国家重点基础研究发展计划项目(973计划)(2009CB219801;2011CB710706);国家自然科学基金项目(51025624);国际科技合作项目(2010DFA72760-609)

摘　　要：利用锅炉尾部烟气余热加热回热系统中的凝结水,可排挤部分抽汽返回汽轮机内继续膨胀做功,在一定程度上提高机组效率,有利于电厂的节能降耗。在典型百万千瓦机组选定工况的基础上,结合工程约束条件限制,开展利用电站锅炉烟气余热加热凝结水的多种典型集成方案设计;并运用"等效焓降法"和"常规热平衡法"对其进行热力学比较分析。研究结果表明:两种方法的计算结果非常接近,可作为工程计算的相互验证;低温省煤器回收的热量在满足约束条件的情况下排挤更高级的抽汽可获得更好的节能效果;同时,合理利用串并联方式有可能获得更好的热力学性能。The heat recovery of utility boiler flue gas,used to heat condensed water in the feed water system,can squeeze out proportion of the extraction to return the turbine to continue expansion of acting work.It partly improves unit efficiency and reduces plant coal consumption.Based on the selected working conditions of typical ultra-supercritical units and combined with engineering constraints,this paper carries out a variety of typical integrated excogitations of heating condensed water by utilization of flue gas heat recovery.Both equivalent enthalpy drop method and conventional thermal balance method are used for thermodynamic comparison and analysis.The research shows that computed results of the two methods are very close,which can check each other under engineering computation.On condition that low temperature economizer meets the constraints,it will have better energy conservation effects when high-grade steam extraction is replaced.Simultaneously,reasonable series-parallel connection methods may achieve much better thermal and comprehensive performance.

关 键 词：电站节能 低温余热利用 热力学分析 常规热平衡法 等效焓降法 

分 类 号：TM621.4[电气工程—电力系统及自动化]