Study On The Thermoeconomic Performance Of Gas-Steam Combined Cycle With Different Intake Air Cooling Modes

The domestic energy reform is facing challenges such as cleanliness,environmental protection and high efficiency.The Gas Turbine Combined Cycle(GTCC)system is a thermal power generation technology that has high efficiency and better environmental performance through cascade utilization of energy.It is one of the indispensable high-efficiency power generation technologies in the future energy structure.However,the actual operation of gas turbine power plants is affected by environmental parameters,which limits the load output of the unit and reduces its power generation efficiency.In this paper,the typical F-class GTCC system is respectively coupled with the lithium bromide refrigeration system and the spray evaporative cooling system.Under different intake air cooling modes,the change rules of GTCC system performance gain with different environmental parameters are studied.The main research contents are as follows:(1)The thermal performances of GTCC system using double-effect lithium bromide refrigeration system are studied.The models of GTCC system and refrigeration system are established by Aspen plus software,and the changes in performance parameters of the GTCC system after refrigeration system intake air cooling under different environmental parameter conditions are analyzed.The results show that the higher the ambient temperature is,the lower the relative humidity is,the greater the net increase in the output power of the GTCC system after refrigeration system intake air cooling is.However,the increase in the demand for cooling capacity increases the pumping power loss and weakens the growth trend of the net increase of GTCC system output power.The increase in the relative humidity of the environment increases the condensation of water vapor during the cooling process of the refrigeration system,which greatly increases the load of the refrigeration system and causes the decrease of the thermal efficiency of the GTCC system.(2)The thermal performances of GTCC system using spray evaporative cooling system are studied.The model of the spray evaporation system is built by python software,and simulation calculation analysis is carried after coupling with the GTCC system model.The results show that gas turbines and steam turbines have different changing trends affected by environmental parameters,but the change law of the unit output power increment after intake air cooling is the same.The higher the ambient temperature is,the lower the relative humidity is,the greater the increase in the output power and thermal efficiency of GTCC system is.When the gas turbine operates at a limited load,the application of spray evaporative cooling technology can effectively save the gas consumption of the gas turbine and effectively reduce the power generation cost of the unit.(3)Comparative analysis of thermal economy of applying lithium bromide refrigeration system and spray evaporative cooling system is made in this paper.Based on thermoeconomic analysis method,the unit investment cost calculation model is established,and the economic characteristics of two different cooling methods are discussed.The results show that the GTCC system has a higher annual effective power generation capacity after applying the lithium bromide refrigeration system;the unit power generation cost of the GTCC system will be reduced after the spray evaporative cooling system is applied.