Carbon dioxide capture using a CO2-selective facilitated transport membrane

A novel CO2-selective membrane with the facilitated transport mechanism has been synthesized to capture CO2 from the industrial gas mixtures, including flue gas. Both mobile and fixed amine carriers were incorporated into the cross-linked poly(vinyl alcohol) (PVA) during the membrane synthesis. The membrane showed desirable CO2 permeability (with a suitable effective thickness) and CO2/N-2 selectivity up to 170 degrees C. In the CO2 capture experiments from a gas Mixture with N-2 and H-2, a permeate CO2 dry concentration of >98% was obtained, using steam as the sweep gas. The effects of the feed flow rate and the sweep:feed molar ratio on the membrane separation performance were investigated. A one-dimensional isothermal model was established to examine the performance of a hollow-fiber membrane module composed of the described CO2-selective membrane. The modeling results Show that a CO2 recovery of >95% and a permeate CO2 dry concentration of >98% are achievable from a 1000 standard cubic feet per minute (SCFM) (or 21.06 mol/s) flue gas stream with a 2 ft (0.61 m) hollow-fiber module that contained 980 000 fibers.