A Design Study On The Cryogenic Recovery Of Ethane From Natural Gas In A Gas Field In Xinjiang

Natural gas is a non-renewable fossil energy source,which has become the chief energy source in the primary energy structure because of its advantages of convenient use,high calorific value and low pollution.The development and utilization of natural gas has become the trend of energy development in the world today.This thesis investigates the development status of natural gas gathering and transportation treatment at home and abroad.By combining the actual working conditions,rationally selecting the light hydrocarbon recovery process and refrigeration process,it designs the process to recover the light hydrocarbon components in natural gas and adapts the process,effective energy loss analysis and optimization of heat exchanger networks.The main contents are listed below.Taking the adaptive transformation of A gas field as the research object,the treatment station adopts the shallow cooling treatment process of“J-T valve+alcohol injection antifreeze”.And the cooling depth is limited.The hydrocarbon component cannot be fully recovered,and the cryogenic recovery ethane scheme is proposed and designed in combination with specific development conditions.The natural gas ethane recovery process was simulated and optimized by HYSYS.The ethane yield was 97%,and the LPG yield was 99%.From the three aspects of raw material gas volume,temperament pressure and temperament composition,adaptive analysis is carried out to study the adaptability of process equipment to change.Effective energy loss analysis on the heat exchange equipment,throttling equipment,compression equipment and expansion equipment in the process was perform to determine the effective energy loss distribution,and study the effective energy utilization rate of the process.The Aspen Energy Analyzer was used to simulate the heat transfer of the calculation process to draw the heat exchange network map and optimize the heat exchange network.So the goal of energy saving and consumption reduction are achieved.Aiming at the presence of medium and low pressure feed gas in A gas field,the application research of mixed refrigerant refrigeration ethane recovery process was carried out.The natural gas ethane recovery process was simulated and optimized by HYSYS.The ethane yield was 97%,and the LPG yield was 99%.The composition and ratio of the mixed refrigerant directly affects the power consumption of the system.Choosing four refrigerants:CH₄,C₂H₄,C₃H₈and n-C₅H₁₂,the ratio is0.4031:0.2198:0.1973:0.1798.The effects of mixed refrigerant on the process were studied from the aspects of feed gas composition,mixed refrigerant parameters,refrigerant composition and refrigeration depth.Adaptability to the process,analysis of effective energy losses is performed.And the heat exchange network is optimized.Taking the associated gas in the oil field as the research object and the maximum benefit of engineering as the research goal,study was comparative on process of mixed refrigerant refrigeration process and expander refrigeration process.When the yield is the same,the process energy consumption is compared,when the energy consumption is approximately the same,the benefit comparison is performed.Combined with the relevant research in Chapters 3 and 4,the refrigeration process suitable for low pressure associated gas is determined.