联产乙烷的天然气提氦工艺研究

Research on helium extraction process from natural gas with co-production of ethane

为了解决单一的天然气深冷分离提氦工艺中设备能耗大、投资大、效率低的问题,将天然气深冷分离提氦工艺与膜分离提氦工艺结合以提高氦体积分数与回收率,同时结合天然气乙烷回收工艺实现冷能的最大化利用,建立了联产乙烷的天然气深冷-膜分离提氦工艺。利用HYSYS软件对联产乙烷的天然气深冷-膜分离提氦工艺与单一的天然气乙烷回收工艺和深冷-膜分离提氦工艺进行流程模拟。模拟结果表明,4种典型乙烷回收工艺中气体过冷工艺的乙烷回收率最高,可达90.13%;将天然气深冷分离提氦工艺与膜分离提氦工艺结合后氦体积分数由66.77%提高到了99.6%;联产乙烷的天然气深冷-膜分离提氦工艺可以有效地集成回收和利用冷量,相较天然气深冷-膜分离提氦工艺+部分干气循环工艺,总压缩能耗低23.10%,单位综合能耗低20.46%。

In order to solve the problems of high energy consumption,large investment and low efficiency in single cryogenic separation process for helium extraction from natural gas,the cryogenic separation process is combined with membrane separation process for helium extraction to improve the purity and recovery rate of helium.At the same time,natural gas ethane recovery process is also combined to maximize the utilization of cold energy,and a cryogenic separation-membrane separation process for helium extraction from natural gas with co-production of ethane is established.HYSYS software is utilized to simulate the combination process with co-ethane production,four independent natural gas ethane recovery processes and the cryogenic separation-membrane separation,respectively.Simulation results indicate that among four typical independent ethane recovery processes,GSP process has the highest ethane recovery rate,reaching 90.13%.The purity of helium increases from 66.77%to 99.6%after the combination of cryogenic separation and membrane separation.The established natural gas cryogenic-membrane separation helium extraction process with ethane co-production can effectively integrate the recovery and utilization of cold energy,its total compression energy consumption is 23.10%lower than that of the post-expansion nitrogen cycle refrigeration helium extraction process+RSV process,and the unit comprehensive energy consumption is 20.46%lower.