Modeling and Design of Carbon Molecular Sieve Membranes for CO2 Capture from Combined Cycle Flue Gas

Chief among concerns in the emergence of environmental accountability is the magnitude of pollution stemming from energy generation and industrial use of fossil fuels. As such, carbon capture measures helping to curtail emissions of greenhouse gases, mostly CO₂, have proven to be vital. Though many standing practices are effective at decreasing CO₂ levels, a more novel but also promising form of Carbon Capture and Storage (CCS) technology is that of membrane separations, specifically of Carbon Molecular Sieve (CMS) varieties. These membranes show strong ability to separate challenging pairs of gases with highly selective permeabilities, with the added potential of being more cost effective and energy efficient than traditional CCS systems.

In this work, a CMS system is modeled based on experimental data from the literature to separate an NGCC (Natural Gas Combined Cycle) flue gas stream taken from a U.S. Department of Energy benchmark amine-scrubbing CCS system. The simulated model shows the membrane’s ability to separate CO₂from the mixture, with expected decreases in operating costs. Simulation results also indicate that the membrane setup can achieve similar results to the amine scrubbing unit for CO₂separation, but the feasibility of implementation on this scale is yet to be determined. A preliminary economic analysis of the membrane was then undertaken to provide a costing estimate for the modeled system. The decrease in energy consumption and high degree of separation parameters associated with this setup suggest that CMS membranes could be viable alternatives to conventional CCS systems.