Conceptual process design and simulation of membrane systems for integrated natural gas dehydration and sweetening
Conceptual process design and simulation of membrane systems for integrated natural gas dehydration and sweetening
复制标题
DOI：
10.1016/j.seppur.2020.116993
复制
发表时间：
2020-09-15
影响因子：
8.6
通讯作者：
Hillestad, Magne
中科院分区：
文献类型：
--
作者：
He, Xuezhong;Kumakiri, Izumi;Hillestad, Magne
海底天然气加工因其较小的环境足迹而吸引了越来越多的关注。天然气（NG）脱水和脱硫是主要的加工步骤，以避免管道堵塞和由水和CO2的存在引起的腐蚀。三甘醇（TEG）和胺吸收是这些应用的商业技术。然而，膜技术被认为是替代海底天然气处理技术的有前途的解决方案，它提供了无人操作，而不需要快速定期维护。在这项工作中，一个混合膜工艺设计的集成脱水和脱硫的饱和天然气含有10摩尔%的CO2，和工艺操作参数，如级间进料和渗透压力进行了研究。模拟结果表明，第二级单元的最佳渗透压力为4 bar，第三级单元的最佳进料压力和渗透压力分别为15 bar和2bar。据估计，最低比成本< 2.71 × 10（-3）$/m（3）低硫天然气可实现净化天然气中<2.5mol%CO2的分离要求，并捕集高纯度CO2（> 95mol%），以提高天然气回收率。然而，由于在模拟中使用的60巴的高压下脱水膜的相对低的水选择性，烃损失仍然相当高。因此，应追求在高压下具有高H2O/CH 4选择性的先进膜，以促进所设计的膜系统在海底天然气脱水和脱硫中的应用。
Subsea natural gas processing attracts increased interest due to the smaller environmental footprint. Natural gas (NG) dehydration and sweetening are the main processing steps to avoid pipeline plugging and corrosion caused by the presence of water and CO2. Triethylene glycol (TEG) and amine absorption are the commercial technologies for these applications. However, membrane technology is considered as promising solutions for alternative subsea gas processing technologies, which provides unmanned operations without the requirements for rapidly periodical maintenance. In this work, a hybrid membrane process was designed for integrated dehydration and sweetening of a saturated natural gas containing 10 mol% CO2, and the process operating parameters such as inter-stage feed and permeate pressures are investigated. The simulation results indicated that the optimal permeate pressure in the 2nd -stage unit is 4 bar, and the optimal 3rd-stage feed and permeate pressures arel 5bar and 2 bar, respectively. The minimum specific cost of < 2.71 x 10(-3) $/m(3) sweet natural gas was estimated to achieve the separation requirement of < 2.5 mol% CO2 in purified NG together with captured high purity CO2 (> 95 mol%) for enhanced gas recovery. However, due to the relatively low water selectivity of the dehydration membranes at high pressure of 60 bar used in the simulation, the hydrocarbon loss is still quite higher. Thus, advanced membranes with high H2O/CH4 selectivity at high pressure should be pursued to promote the application of the designed membrane system for subsea natural gas dehydration and sweetening.