System Characteristic Analysis of Waste Heat Recovery and Cascade Utilization of Tail Flue Gas of Power Boiler

doi:10.11930/j.issn.1004-9649.201909089

Abstract

Abstract: The exhaust gas temperature of the power station boiler is generally 130~150 ℃. Further recovery of flue gas waste heat is beneficial for the reduction of coal consumption and pollutant emissions. Regarding the different flue gas parameters at various parts of the tail of the power station boiler, the waste heat recovery system is formulated with two-stage heat exchangers installed, i.e., one after the air preheater and the other after the wet desulfurization device. In consideration of the operation of the 330 MW coal-fired power station boiler, the effects of heat transfer, condensate and static pressure difference on both sides of the two-stage heat exchangers and the reduction of coal consumption for power generation were analyzed under different load conditions. Change of solid particulate matter in flue gas before and after heat exchanger was also monitored. The results show that the heat exchange capacity of the primary heat exchanger is significantly higher than that of the secondary heat exchanger, and the condensed water mainly occurs in the secondary heat exchanger. The standard coal consumption reduction value can reach up to 3.09 g/(kW·h). Besides, the content of solid particles in the flue gas after the heat exchanger is significantly reduced. This paper provides certain reference value for the waste heat recovery of flue gas from power station boilers.

Key words: power boiler, tail flue gas, waste heat recovery, cascade utilization, heat exchanger, coal consumption for generation

TENG Da, LI Tielin, LI Ang, AN Liansuo, CHEN Haiping, SHEN Guoqing. System Characteristic Analysis of Waste Heat Recovery and Cascade Utilization of Tail Flue Gas of Power Boiler[J]. Electric Power, 2020, 53(7): 189-196.

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URL: https://www.electricpower.com.cn/EN/10.11930/j.issn.1004-9649.201909089

https://www.electricpower.com.cn/EN/Y2020/V53/I7/189

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