The Study Of Liquid Oxygen Direct Fired Power Cycle Based On Energy Storage And Carbon Capture

Based on the current energy and environmental issues,this paper presents a new cycle to achieving the purpose of shifting peaks and protecting the environment.In the trough of the grid,the system manages to store energy by using off-peak electricity to produce liquid oxygen.Then pumping LNG and liquid oxygen into the burner to react.The outlet gas expanded in turbines,which converted the stored energy back into electricity.In the process,carbon dioxide in the outlet gas is liquefied using the "cold energy" of liquid oxygen and LNG.Firstly,the simple circuit of the system is established.Using Aspen plus to simulate the circuit and analyzing simulation results.Because of the higher temperature of burner outlet,the water is selected as the circulating working fluid to control the burner temperature.The improved water circulation system is simulated by Aspen plus,to investigate the influence of turbine inlet pressure and temperature on the system.With the increasing of turbine inlet temperature and fixed inlet pressure,the turbine output power is rising continuously,while the plant power consumption ratio continues decreasing.The system's power generation efficiency and equivalent power generation efficiency continue to improve.Similarly,when the turbine inlet pressure increases and inlet temperature unchanged,the turbine output powe and the plant power consumption ratio will both increase.The system's heating efficiency and equivalent power generation efficiency increase as well.However,with the continuous rise of turbine inlet pressure,the system efficiency increases slowly.Secondly,considering that the specific volume of the carbon dioxide is smaller than that of water,the system flow of carbon dioxide which is used as circulating working fluid has been established to reduce the size of the equipment.The system is also simulated in Aspen plus to investigate the influence of turbine inlet pressure and temperature by changing the parameters.It is found that if the turbine inlet temperature increases and inlet pressure unchanged,the output power of the turbine rising while the plant power consumption ratio decreasing.Meanwhile,the system's heat efficiency and equivalent power generation efficiency will increase.Keeping the turbine inlet temperature unchanged and the turbine inlet pressure sustained rising,results can be found as follows:the output power of the turbine increases,the plant power consumption ratio increases,and the system power generation efficiency and equivalent power generation efficiency increase too.Then,the efficiency of different systems of different circulating fluid are compared.When the turbine inlet temperature is same,the power generation efficiency and equivalent power generation efficiency of the system used water as circulating fluid is higher than that of the carbon dioxide.But,when the turbine inlet pressure continues to rise,the efficiency of generating power and the equivalent power generation efficiency of the system with carbon dioxide are increasing more obviously,and the value is becoming close to the system based on water working fluid.Finally,by comparing the characteristics of different space separation technologies,the proper air separation process is selected for the system.On the one hand,eliminating unnecessary part of the process of argon blowing,on the other hand,circulating with nitrogen improves the liquid oxygen production.The simulation results by Aspen plus are similar to the power consumption of existing air separation system.By the calculation of different operation schemes of the air separation system,the air separation system is the most economical by using off-peak electricity,considering that the unit power consumption of the liquid oxygen is the lowest.Compared with the German compressed air energy storage power plant,taking the power consumption,heat consumption,efficiency and the volume of the storage system into consideration,the system in this article is better.