| In the process of transporting natural gas to the users through the high-pressure pipeline network,it needs to go through the gas station for multi-stage pressure regulation,and the pressure energy will be greatly lost in this process.Under the carbon peaking and carbon neutrality goals,it is one of the trends in the development of the energy industry to build an energy supply system for the gas station for the recovery of pressure energy.Based on this,this thesis designs and studies the power generation system using the pressure energy of the gas station,the combined cooling and power generation system and the combined cooling heating and power generation system with Solid Oxide Fuel Cell(SOFC)as the key equipment for varying grades of gas stations.The main achievements are as follows:Based on energy analysis and exergy analysis,performance evaluation indexes are proposed,and the pressure exergy,cold exergy and temperature of high-pressure natural gas after pressure regulation are analyzed.The SOFC ontology simulation is established by using Aspen Plus,and its reliability is verified by the comparative analysis with the simulation results in the literature.Through the analysis of variable working conditions,the operating pressure and operating temperature of SOFC in the combined energy supply system are determined.For the small gas station represented by the M pressure regulating station,the pressure energy power generation system process was designed based on the electricity demand collected from the operation data,and the trial production of the pressure energy power generation system was completed.Based on specific working conditions,the energy efficiency,economy and environmental protection of the pressure energy power generation system are evaluated.The results show that the pressure energy power generation system provides a new way for the self-consumption of gas stations in remote and power-hungry areas.It has practical application guiding significance.For the medium-sized gas station represented by the D gate station,the power generation and ice-making co-production system process is designed based on specific working conditions,and the simulation calculation is completed.The effects of intake air temperature and intake air flow on outlet temperature and heat exchange were analyzed.As the intake air temperature increases,the outlet temperature increases linearly,and the heat exchange decreases linearly;as the intake flow increases,the outlet temperature does not change,and the heat exchange increases linearly.Based on the analysis results,the energy efficiency,economy and environmental protection of the cogeneration system were evaluated,and the natural gas-refrigerant heat exchanger with lower exergy efficiency was determined as the direction of optimization and improvement in the future.For the large-scale gas station represented the T gate station,based on the principle of comprehensive cascade utilization of physical energy and chemical energy,and according to the cooling,heating and electric load requirements of Gate T station and its surrounding buildings,two available cooling,heating and power plants are proposed.For the energy supply system,the system is simulated based on specific working conditions,and the scheme comparison and selection are completed based on the energy analysis and exergy analysis results of each system,and the optimal energy supply system is determined.After the optimal energy supply system is determined,the system simulation is completed based on the working conditions of the heating season,the cooling season and the transition season.The research results show that the optimal energy supply system can basically meet the annual cooling,heating and electric load demands of the T gate station and its surrounding buildings.It provides a new way for comprehensive utilization of pressure energy in large gas stations in our country,and has theoretical guiding significance. |
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