联产LNG天然气低温-膜分离提氦工艺模拟设计

Simulation design of process of low-temperature and membrane separation for helium extraction and LNG co-production from natural gas

为了解决传统提氦工艺单位能耗高、提氦效率低和经济成本高等问题,对天然气低温-膜分离提氦工艺和联产液化天然气(LNG)的天然气低温提氦工艺进行了分析,结合各工艺的优势,设计了联产LNG天然气低温-膜分离提氦工艺。使用Aspen HYSYS软件对3种工艺的装置综合能耗、氦气回收率、氦气含量(体积分数,下同)进行了模拟计算。结果表明,装置在最低操作温度为-188.3℃的情况下,联产LNG天然气低温-膜分离提氦工艺的氦气回收率最高(99.99%),提取氦气含量最高(99.95%),LNG产量为678.4 kmol/h,LNG液化率为94.6%。与天然气低温-膜分离提氦工艺和联产LNG天然气低温提氦工艺的相应运行参数相比,联产LNG天然气低温-膜分离提氦工艺压缩机总能耗降低了12.68%,装置综合能耗降低了18.75%。最终建立的联产LNG天然气低温-膜分离提氦工艺可以有效提高氦气回收率和纯度,降低了能耗和投资成本,实现了能量最大化利用,同时可以生产出两种产品(精氦和LNG)。

In order to solve the problems of high energy consumption,low helium extraction efficiency and high economic cost of traditional helium extraction process,the process of low-temperature and membrane separation for helium extraction from natural gas and the process of low-temperature helium extraction and LNG co-production from natural gas were analyzed.Combined with the advantages of each process,the process of low-temperature and menbrane separtion for helium extraction and LNG co-production from natural gas was designed.Aspen HYSYS software was used to simulate the comprehensive energy consumption,helium recovery rate and helium content(volume fraction,the same as below)of the three processes.The results show that the helium recovery rate of the process of low-temperature and membrane separation for helium extraction and LNG co-production from natural gas is the highest when the condition of the minimum operating temperature is-188.3℃,which can reach 99.99%.The extracted helium content is the highest(up to 99.95%),and LNG production is 678.4 kmol/h,and LNG liquefaction rate is 94.6%.Compared with the operational parameters of the process of low-temperature and membrane separation for helium extraction from natural gas and the process of low-temperature helium extraction and LNG co-production from natural gas,the total compressor energy consumption of the process of low-temperature and membrane separation for helium extraction and LNG co-production from natural gas is reduced by 12.68%,and the comprehensive energy consumption of the device is reduced by 18.75%.The final process of low-temperature and membrane separation for helium extraction and LNG co-production from natural gas can effectively improve helium recovery rate and purity,reduce energy consumption and investment costs,maximize energy utilization,and produce two products(refined helium and LNG)at the same time.