Study On Thermoelectric Decoupling Method Of Captive Power Plant For Multi-load Demands

In September 2020,Chinese President Xi Jinping proposed at the United Nations Biodiversity Summit that the country would be carbon neutral by 2030 and 2060.At present,the low efficiency of coal-fired power generation in captive power plants can not be included in the peak range of power grid.As one of the important ways to save energy and reduce emissions and improve energy efficiency,thermal decoupling technology is very mature and has been widely used in the thermal power industry.With the rapid development of renewable energy generation,the lack of flexibility is becoming more and more obvious,so it is very important to solve the contradiction and enhance the flexibility of the power side by means of thermoelectrolysis.The application of thermoelectrolysis decoupling technology to captive power plants will help to bring captive power plants into the peak range of power grid regulation,deepen the potential of peak regulation,solve the current and future problems of renewable energy absorption,and reduce discard light.In this paper,four thermoelectric decoupling schemes are proposed for the captive power plant based on the above conditions,namely,the zero output scheme of low pressure cylinder,the steam extraction combined with exhaust steam heating scheme under high back pressure,the absorption heat pump decoupling scheme and the compression heat pump decoupling scheme.The zero output scheme of the low pressure cylinder realizes thermoelectric decoupling by cutting off the low pressure cylinder,and the steam extraction combined with exhaust steam heating scheme under high back pressure achieves the purpose of heating by increasing the exhaust steam pressure.The absorption heat pump decoupling scheme and the compression heat pump decoupling scheme both recover the heat of the condenser cooling water to achieve higher heating load.Through the thermodynamic analysis of the four thermoelectric decoupling schemes,the energy conversion mechanism and the main location of energy loss are identified,which provides more scientific guidance for the transformation of captive power plants.In terms of the maximum heat load added after the optimization and transformation,the zero output scheme of the low pressure cylinder increases the heat supply most obviously.From the point of view of the electric load rate under the condition of maximum heat supply without modification in the original case,the peak-shaving capacity of the unit has been greatly improved by the zero output scheme of the low pressure cylinder.