中文摘要：

在分析空冷机组运行特点的基础上,提出了一种空气-烟气余热联合回收系统,即空冷岛出口的热空气作为锅炉燃烧用风,进入空气预热器被加热,同时在锅炉尾部加装低温省煤器,加热低压凝结水,以节省汽轮机抽汽量.以某典型600 MW亚临界直接空冷机组为例,分析了空气-烟气余热联合回收系统的热力学特性和节能效果.结果表明：在典型工况下,空气预热器入口温度可提高约25 K,机组供电煤耗降低约1.93 g/（kW·h）,年节约标准煤约7 000 t,节约燃料费700余万元（按机组年运行5 500 h,标准煤价格为1 000元/t计算）,经济效益显著.

英文摘要：

Based on detailed analysis of operation characteristics of an air cooling unit,a combined air-flue gas waste heat recovery system was proposed,in which the hot air from air cooling unit is to be heated in air preheater for purposes of boiler combustion,and simultaneously,the low temperature economizer set at boiler tail is used to heat the low-pressure condensed water,thus saving the steam extracted from steam turbine.Taking a typical 600 MW subcritical direct air cooling unit as an example,the thermodynamic characteristics and energy-saving effects of its air-flue gas waste heat recovery system were analyzed.Results show that obvious economical effects can be obtained for the air-cooling unit under typical working conditions,with an increased inlet temperature of air preheater by 25 K,a reduced power supply coal consumption by 1.93 g/（kW · h）,an annually economized standard coal consumption by 7 000 t,equivalent to 7 million RMB fuel cost （based on the coal price of 1 000 RMB/t with an annual running time of 5 500 hours）.