Simulation study of a flue gas waste heat and water co-recovery system

Abstract To improve the economy and safety of the power plant, the waste heat and water co-recovery system with two-stage flue gas coolers (FGC) was put forward. Two-stage FGCs were equipped between the induced draft fan (IDF) and the wet limestone flue gas desulfurization (WFGD), the WFGD and the wet stack. To ensure safety, Each stage flue gas cooler consisted of two independent heat exchangers (hot end heat exchanger named FGC-H, cold end heat exchanger named FGC-C) with a coupling fluid which is circulated by a pump, and this method named fluid coupled indirect heat exchange (FCHE) technology. Due to the temperature of flue gas through two FGC-Hs being below the acid and/or water vapor dew points, two FGC-Hs adopted the plastic heat exchanger to prevent the sulfur attack. Then, the impact of the waste heat and water co-recovery system on the dynamic behavior and the economic performance of the studied power plant have been verified by simulation tests on the full-scale simulator of the studied 330 MW coal-fired power plant. The results show that the waste heat and water co-recovery system could effectively improve the economy and environmental performance of the studied power plant. It is an effective way to realize further flue gas waste heat utilization.