Off Design Performance Optimization Of Compressed Air Energy Storage System Coupled With Gas Turbine

In recent years,with the attention and development of renewable energy such as solar energy and wind energy in China,the consumption capacity of power grid for fluctuating unstable power generation has tended to the upper limit.In some areas where new energy resource is rich,there has been a relatively serious abandonment of wind and light,which not only causes the loss of resources but also limits the further development of renewable energy in China.Because energy storage technology is an effective way to solve the problem of new energy consumption,in recent years,it has gradually attracted the attention of many scholars.Compressed air energy storage(CAES)technology is a kind of power energy storage technology suitable for both large and small scale electric power systems,which has the characteristics of good economy,high safety,friendly environment,fast speed response,long life and so on,and has good development potential.For a long time,off-design operation is an important problem of CAES system,which has a key impact on its efficiency and economic benefit of energy storage and release process.Therefore,this paper takes the compressed air energy storage system with gas turbine as the research object,and studies the off-design characteristics of its energy storage and release process.The main research contents and conclusions are as follows:(1)Based on the modular modeling method,the mathematical model of compressor,expander,combustion chamber,heat exchanger,regenerator,gas chamber and other equipment is established in this paper.According to the model,the change rule of flow rate with time in the process of energy release of caes system is deduced.Combined with ebsilon simulation software,the simulation model of compressed air energy storage system coupled with gas turbine is established.(2)According to the dynamic characteristics of the system,it shows that the equipment of the system deviates from the design condition seriously,especially the compressor and expander,which leads to the low average efficiency of the energy storage process and the energy release process.(3)In order to solve the problem of low performance of CAE system,this paper optimizes the system according to the characteristics of the system.(1)In view of the energy storage subsystem of the CAES model,a new operation strategy is proposed,which changes the operation mode of the compressor in the original system.Through the optimization of the design flow and the design pressure ratio of the compressor,the performance parameters which are most in line with the conditions of variable working conditions are obtained.On this basis,the system switching pressure is optimized with the goal of minimizing the total power consumption in the energy storage process.The results show that the switching system operation mode can make the total power consumption minimum when the pressure is 0.985 MPa,which is 1104088.7MJ.(2)In view of the energy release subsystem of caes model,a new operation strategy is put forward.When the operation efficiency of gas turbine is too low,the system switches to air turbine operation.According to the efficiency characteristics of the expander,the design flow of the gas turbine and the air turbine and the switching pressure of the system are optimized synchronously to maximize the total revenue of the system in the process of energy release.Not only the optimal performance parameters of the expander are determined,but also the optimal switching pressure of the system is 3.823 MPa.