Membrane system design and process feasibility analysis for CO2 capture from flue gas with a fixed-site-carrier membrane

Abstract Seeking an energy efficient and environmentally friendly technology for CO 2 capture could be promising for reduction of CO 2 emissions. Membranes have already been commercially used for selected gas separations and have potential to be used for CO 2 capture. However, process and economic feasibility of membrane separation system significantly depends on not only membrane materials but also process operating conditions. Thus, membrane system design by process simulation was conducted in this work. A single stage membrane unit was designed to accomplish specific separation requirements of >80% CO 2 capture ratio at a maximum acceptable membrane area 600,000 m 2 . The obtained characteristic diagrams showed that a minimum membrane performance of CO 2 permeance 2 m 3  (STP)/(m 2  h bar) and CO 2 /N 2 selectivity 135 should be achieved at a stage-cut of 15.2% and a feed and permeate pressure of 2.5 bar and 250 mbar, respectively. A two-stage membrane system using high performance fixed-site-carrier membranes by integration of compression heat was designed to achieve >80% CO 2 capture ratio and >95% CO 2 purity from a 18,260 kmol/h flue gas in a refinery. The simulation results showed nice potential for CO 2 capture with a specific energy consumption of 1.02 GJ/ton CO 2 and a capture cost of 47.87 $/ton CO 2 captured.