CO2 Separation by Using a Three-stage Membrane Process

In this work, a three-stage membrane process for CO2 separation was proposed and optimized. The results of this study revealed that the proposed technology is a suitable process for the CO2 separation at higher concentrations. In addition, MATLAB was used to simulate and obtain the optimal operational parameters for a three-stage membrane process. A partial cycle was established, and the CO2 was recovered from the permeation side of the second-stage membrane, which enhanced the purity of the CO2 gas stream. The results of this study indicated that when the CO2 concentration was higher than 50% at a flow rate of 100000 Nm3 d–1, CO2 separation could be achieved under optimal operating conditions. Under conditions where the membrane areas were 2400, 3800, and 1800 m2 for the first-, second-, and third-stage membranes, respectively, and where the operational pressure at the first- and third stage membranes were 3.0 and 2.5 MPa, respectively, the CO2 separation fraction was higher than 90%, and the CH4 loss rate was less than 5%. The results of this study indicate a high potential for practical application.