以典型660 MW超临界燃煤发电机组为研究对象，进行了烟气余热梯级利用系统的概念设计。基于热力学第一定律和热力学第二定律分析了回转式空气预热器传热过程的热力学完善程度，烟气余热梯级利用系统热量置换过程的火用效率，燃煤机组整体性能以及考虑回转式空气预热器内部硫酸氢铵（ABS）沉积沾污因素的运行节能效益。研究结果表明：随着烟气余热利用系统能级平衡节点温度升高，回转式空气预热器传热不可逆损失减小，系统热量置换过程火用效率升高，机组发电标准煤耗率降低；对于确定的能级平衡节点温度，存在最佳的旁路烟气比例，分别对应热量置换过程火用效率最高和机组发电标准煤耗率最低；考虑ABS沉积因素后，烟气余热利用系统的可运行参数区间受限，影响系统的节能收益。

In this paper,a 660 MW supercritical coalfired generating unit is taken as an example,and the conceptual design of a flue gas waste heat cascade utilization system is carried out.Based on the first and second laws of thermodynamics,the thermodynamic perfection of the heat transfer process of the rotary regenerative air preheater,the exergy efficiency of the heat displacement process of the flue gas waste heat cascade utilization system,the overall performance parameters of the coalfired unit and the energy saving benefits taking into account the factor of deposition and fouling of ammonium bisulfate (ABS) are calculated and analyzed.The research results show that as the energy level balance node temperature of the flue gas waste heat utilization system increases,the irreversible heat transfer loss of the rotary air preheater decreases,the exergy efficiency of the heat displacement process increases and the standard coal consumption rate decreases.Under a certain energy level balance node temperature,there are optimal bypass flue ratios,which correspond to the highest exergy efficiency of the heat displacement process and the lowest standard coal consumption rate for power generation respectively.After considering the ABS deposition factor,the operating parameter range of the flue gas waste heat utilization system is limited,which affects the energy saving benefit of the system.

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