Energy Consumption Analysis of Cryogenic-membrane Hybrid Process for CO_2 Capture from CO_2-EOR Extraction Gas

CO_2-EOR (CO_2-enhanced oil recovery) is an effective method to increase oil recovery. With more and more exploitation of oilfields, a large amount of CO_2 will spill out the surface, which can cause serious environmental problems. At present, high energy consumption, low CO_2 purity and recovery are still the main challenges of single CO_2 capture technology. Therefore, the combination of different CO_2 capture technology is a reasonable choice to overcome these bottlenecks. In this work, a cryogenic-membrane hybrid process for the CO_2 capture from extraction gas was proposed. In detail, the main parameters of cryogenic-membrane hybrid process (i.e., CO_2 content in feed gas, compression pressure, membrane area, liquefaction temperature) which effect on CO_2 properties were investigated. The simulation results indicated that the CO_2 purity and recovery rate of cryogenic-membrane hybrid process can achieve 99% and 96%, respectively, and the energy consumption of the whole system was less than 850 MJ t^(-1) CO_2. Compared with membrane and cryogenic process, cryogenic-membrane hybrid process can save about 10% energy consumption. The results of this work indicate that cryogenic-membrane hybrid process has great potential for practical application.