| Underground gas storage,as an effective means of natural gas storage and peak adjustment,has received increasing attention.Salt cavern gas storage,as one of the mainstream underground gas storage modes,is suitable for coastal and other salt-rich areas with few oil and gas reservoirs.It is one of the types of gas storage that China will vigorously develop.However,due to the limitation of the pressure regulation method in the conventional salt cavern gas storage,there is unavoidable waste of pressure energy accompanying with the gas production process.Thus,this article proposes two sets of salt cavern gas storage pressure energy utilization systems with different characteristics,in order to be suitable for a variety of application scenarios and needs,realizing the effective use of pressure energy.First,the paper constructs the system which uses the pressure energy of salt cavern gas storage for purification and power generation.The system uses the turbo expander to convert pressure energy into electricity and cold energy,and to use the low temperature generated in this process to complete purification of natural gas.According to the use of cold energy,the system can be divided into two modes,mode one is with cold energy utilization system,and mode two is without cold energy utilization system.Then,this article takes a typical salt cavern gas storage as a case,and uses Aspen Plus software to perform a system simulation to verify the feasibility of system's purification and power generation functions.Simulation experiments show that under design conditions,the power generation exergy efficiency of mode one is 59.9%,the power exergy efficiency of mode 2 is 47.01%,and the ice-making exergy efficiency of mode 2 is 22.06%.Then,the article constructs the system which uses the pressure energy of salt cavern gas storage for purification and energy storage,which combines compressed air energy storage technology with pressure energy utilization of salt cavern gas storage.After simulating and analyzing the working conditions of the same research case,the system's purification and energy storage functions were verified.The efficiency under design conditions was 58.3%,and the energy efficiency of the air pressure part was 53%.The energy density is 13.25 kWh/m~3.In order to clarify the characteristics and performance of the two systems,this paper finally makes a study and comparison of the two sets of pressure energy utilization systems from the perspective of application characteristics,system equipment,and system structure.Then it provides suggestions for the selection and improvement of different systems.Through the construction and simulation research of the above two systems,this paper provides a reference for the utilization of the pressure energy of the produced gas in the salt cavern gas storage.It can improve the energy utilization of the salt cavern gas storage to a certain extent,thereby improving its economy and environmental benefits. |
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