The steam drainage of a cogeneration project contains high thermal energy. If it is not used scientifically and rationally, it will not only cause energy waste, but also affect the power generation of the steam turbine. In order to improve the overall efficiency of the power plant, the design of the cogeneration project will consider adding drainage The cooler is used to recover heat energy and increase the generating capacity of the unit. The 2 drain coolers and 2 water make-up heaters provided for the Guodian Xingyang Cogeneration Project are all PLQ150 type fully welded plate heat exchangers, which are used to recover the waste heat of the 130℃ drain with a pressure of 2.5Mpa and heat to 70℃ The water returned from the heating network is heated to 100°C and sent to the heating network system. Most of the cooled drain is returned to the boiler feed water system for recirculation. A part of the drain is extracted and used to heat the boiler water to raise the boiler water at 20℃ to 78℃. After the drain temperature is reduced by 22℃, it enters the condensate system. The low-pressure heater enters the boiler feedwater system after heating.

The heating network steam trap can make full use of the thermal power of the thermal power plant to reduce coal consumption and increase the generating capacity of the unit. Compared with traditional tube heat exchangers, the PLQ series fully welded plate heat exchanger manufactured by Prepler has the characteristics of high heat transfer coefficient, high pressure and high stability. The products have been widely used in China Resources and Huadian , Huaneng, China Power Investment and other domestic five major power plants in the application of drain coolers in thermal power plants, and the operation is well received by customers.