Process Simulation And Economic Evaluation Of Differential Pressure Power Generationa For Natural Gas Station

Natural gas is a bridge for China's energy structure and is of great significance to achieving "carbon peak" and "carbon neutrality".In the future,natural gas consumption will continue to grow.When natural gas is used for pressure adjustment at the station,a large amount of natural gas pressure can be wasted.The natural gas pressure difference power generation system is a technology for recovering the pressure energy of natural gas for power generation,but this technology has not been effectively promoted.Therefore,based on the principle of engineering thermodynamics,this paper studies the performance of the single-stage expansion and multi-stage expansion differential pressure power generation process of natural gas stations,explores the method of improving the performance of the differential pressure power generation process through the process model,discusses the evaluation method of the differential pressure method based on the process analysis and simulation results,establishes a set of economic evaluation system,and provides a reference for the design and technology promotion of the natural gas pressure differential power generation process.The software Hysys is used to simulate the natural gas pressure difference power generation process,and the simulation shows that the actual project error between the power generation and the pressure difference power generation is 6%.The error analysis proves that the model design is feasible,and the generator efficiency of the model is corrected to 95%.The modified model is used to simulate the single-stage expansion pressure difference power generation process.The results show that the single-stage expansion process can increase the process power generation by preheating natural gas,increasing the flow rate or reducing the outlet pressure.By comparing the simulation results of multi-stage expansion and single-stage expansion process under the pressure regulating condition of 4.5 MPa to 1.6 MPa,it is determined that the two-stage expansion process is the best process under the pressure regulating condition.Based on the research conclusion of the single-stage expansion process,this paper designs the multi-stage expansion pressure difference power generation process and conducts the process simulation.In order to analyze the performance of the process,the zero-degree cold energy of natural gas and the maximum temperature of natural gas after heating are defined as evaluation parameters other than power generation.The analysis of the simulation results of the two-stage and three-stage expansion process under different intermediate pressure conditions shows that the constant expansion ratio working condition is the best working condition for the multi-stage expansion process.This paper selects the evaluation indicators for the differential pressure power generation process of natural gas city gate stations from the three aspects of technology,economy and environmental protection.Through analysis,the economics of the differential pressure power generation process are determined as the evaluation target,and the technical indicators and environmental protection indicators are transformed into economic indicators,and establishes an economic evaluation system of natural gas station pressure difference power generation process based on the internal rate of return as the core evaluation index and the investment recovery period as the auxiliary evaluation index.The research conclusions of this subject provide a reference for the application and construction of the pressure difference power generation technology of natural gas stations,and are of great significance to the design,construction and promotion of future pressure difference power generation projects.