The Research on Recycling Chilled Water Loss of Power Plant for District Heat Supply
|School||Harbin Institute of Technology|
|Course||Heating,Gas Supply, Ventilation and Air Conditioning Engineering|
|Keywords||power plants heat pump stations condenser circulating water energy flowdiagram the energy conversion efficiency evaluation system|
The main content of this paper is the technology of recycling chilled water loss ofpower plant for district heat supply. With the rapid expansion of city size, the carryingcapacity of the environment and the economy problem caused by heat supply is growing,The Cogeneration is recognized as the highest energy conversion efficiency form ofheat source, however, a lot of energy in the power generation process of power stationwere wasted in the form of waste heat, a lot of exhaust steam heat producing by heatingunits is not being utilized but was taken away by circulating cooling water system, anddischarged into the environment. Heating turbine has huge chilled water loss, in order torecover the heat taken away by circulating water, there usually have two ways： First,the low vacuum operation will increase the condenser water temperature, namely lowvacuum operation circulating water heating; Second, improve the energy grade ofrecycled water for heat supply by using heat pump technology. There are four forms ofheat pump stations energy driving including Electric drive, Turbine driven, Gas turbinedriven and Exhaust driven.To study the energy utilization of heat pump station for the recovery of waste heatof circulating water in the steam condenser of a coal-fired power plant, the primaryenergy ratio of the heat pump stations driven by different energy sources for thereclamation of waste heat was analyzed through energy flow diagram. The results showthat the electric heat pump energy-supply system consumes20%electricity although thetotal efficiency of electric heat pump energy-supply system is as well as otherenergy-supply system forms. With the power generation efficiency and heat pumpsystem performance reducing, there may be need to introduce an external power, andthe exhaust driven primary energy factor of steam turbine and gas turbine are higherthan electric heat pump station, so from the point of view of energy utilization, steamturbines and gas turbines have more advantages.This paper proposed as energy quality coefficient for basis and as the energyconversion efficiency for evaluation indicator to evaluate energy conversion systems.With this indicator we can not only reflect the energy of the "quality", but also reflectthe energy of the "quantity", can more comprehensively evaluate a system rational useof energy combined with the device conversion efficiency. The results show that whenthe system is fully condensate, watching from the energy conversion efficiency, steamturbines, gas turbines and exhaust drive exceed electric heat pump station.Finally, this paper puts forward a "4E" as the evaluation index, as levels analysis,financial evaluate, SWOT strategic analysis for evaluation method, established a4E model to evaluate energy conversion devices for recycling cogeneration plant coldsource loss, laid a certain foundation, for district heating planning.