IEC 10 |
| M. C. Trachtenberg, R. M. Cowan, S. L. Goldman, J. J. Ge, Y. J. Qin, and M. L. McGregor. The Sapient’s Institute, New Brunswick, NJ 08901 and Carbozyme, Inc, Bordentown, NJ 08505 |
| Unacceptably high cost is cited as the principal economic barrier to the capture of CO2 from mixed gas streams for purification and/or disposal. Current amine based technologies are expensive ($50-70/Mt) due to required liquid pumping and steam desorption to offset the high binding constant. A preferred embodiment would allow proximate absorption and desorption to occur and would rely on partial pressure differences alone. The enzyme carbonic anhydrase (CA) has evolved repeatedly to effect the rapid capture and release of CO2 solely on the basis of modest pressure differentials, and to do so even in the face of very low partial pressure of CO2 in the feed stream. Capitalizing on this evolutionary opportunity we have developed an enzyme-based, liquid membrane design for the selective capture of CO2 from a variety of mixed gas streams. We have demonstrated the ability to capture CO2 from streams as diverse as air, respiratory gas, flue gas, landfill gas and natural gas, at concentrations ranging from 0.035% to 95%. The design configuration uses a dual hollow fiber array with the feed stream entering the bore of one hollow fiber while the sweep stream enters the bore of the other. At the feed gas-liquid interface the CA converts the CO2 to bicarbonate. The bicarbonate crosses the membrane where, at the sweep gas side, more CA reverses the action converting the bicarbonate to CO2. In comparison with amines with a typical turnover number of 2400:1, CA has a turnover number of 106:1. Captured gas concentrations as high as 80% CO2 can be obtained with feed gas concentrations as low as 0.1% CO2. This continuous process design is stable, does not require high temperatures or pressures, and is insensitive to feed or sweep gas relative humidity. |
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Separations Science Approaches to Carbon Management (Cosponsored by Separation Science & Technology Subdivision)
9:00 AM-11:55 AM, Sunday, March 23, 2003 Convention Center -- Room 393, Oral
Division of Industrial and Engineering Chemistry |