Research on flue gas waste heat recovery system in gassteam combined cycle power plant

Analyses two key issues of the boiler flue gas waste heat recovery, puts forward a new process of district heating system based on the deep recovery of flue gas waste heat. In this process, on the one hand, adopts absorption heat pump and lowtemperature return water of the heat network to realize the deep cooling of the exhaust smoke, on the other hand, combines chimney and spray tower as a compact structure, to overcome the dew point corrosion of flue gas and improve the feasibility of the waste heat recovery. Taking a combined cycle system with three FT83 units as the research object, designs the flue gas waste heat recovery unit (contains a waterwater heat exchanger and an absorption heat pump). Considering the investment and operating cost of flue gas waste heat recovery, optimizes the key parameters of the new system under different flue gas temperatures, and points out that realizing the small temperature difference of the waterwater heat exchanger terminal is the key to improve the economy of the system.