Efficient Facilitated Transport Polymer Membrane for CO2/CH4 Separation from Oilfield Associated Gas

CO2enhanced oil recovery (CO2-EOR) technology is a competitive strategy to improve oil field economic returns and reduce greenhouse gas emissions. However, the arbitrary emissions or combustion of the associated gas, which mainly consists of CO2and CH4, will cause the aggravation of the greenhouse effect and a huge waste of resources. In this paper, the high-performance facilitated transport multilayer composite membrane for CO2/CH4separation was prepared by individually adjusting the membrane structure of each layer. The effect of test conditions on the CO2/CH4separation performance was systematically investigated. The membrane exhibits high CO2permeance of 3.451 × 10−7mol·m−2·s−1·Pa−1and CO2/CH4selectivity of 62 at 298 K and 0.15 MPa feed gas pressure. The cost analysis was investigated by simulating the two-stage system. When the recovery rate and purity of CH4are 98%, the minimum specific cost of separating CO2/CH4(45/55 vol%) can be reduced to 0.046$·Nm−3CH4. The excellent short-to-mid-term stability indicates the great potential of large industrial application in the CH4recovery and CO2reinjection from oilfield associated gas.Keywords:oilfield associated gas;CO2capture;multilayer composite membrane;facilitated transport;CO2/CH4separation