Study On LNG Light Hydrocarbon Separation Process And Cold Energy Utilization Technology

This paper is based on the research project 16JK1594 of Shanxi Education Department.In order to meet the energy demand,China has established LNG receiving stations in coastal areas to import LNG.However,the composition of LNG varies with the origin.The main gas sources in China,such as Australia,Qatar and other countries,produce higher ethane and heavy hydrocarbon components of LNG.Heavy hydrocarbon components will affect the dew point and calorific value of natural gas,and bring a series of transportation and safety problems,while ethane will bring additional economic benefits.Therefore,it is necessary to separate light hydrocarbon components from LNG in order to meet pipeline transportation conditions and gas supply index and improve economic benefits.As far as current research is concerned,condensation is the most economical and effective way to recover light hydrocarbons.LNG itself contains huge cold energy.If light hydrocarbons are separated and recovered by this part of the cold energy,it can not only improve the energy utilization rate,but also create considerable economic benefits.Based on the existing classical separation process of LNG,a new process of separating light hydrocarbons with LNG cold energy was developed by using Aspen HYSYS software for simulation analysis.The six classical processes at home and abroad were compared.The simulation results show that the molar content of methane is 99.22%,the yield of ethane is36.81t/h,the purity is 99.74%,the yield of liquefied petroleum gas is 46.56 t/h,the recovery of ethane is 93.07%,and the recovery rate is the highest.Through economic analysis,it is concluded that compared with the six existing classical separation processes at home and abroad,the optimized process has the highest net profit,the highest return on investment and the shortest return period on investment,which is the optimal process.