CO2 capture by sub-ambient membrane operation

Air Liquide is developing a cost effective hybrid CO2 capture process based on sub-ambient temperature operation of a hollow fiber membrane in combination with cryogenic distillation. Operation of these commercial Air Liquide membranes at low temperatures provides an unprecedented combination of CO2 permeability and selectivity. Both high membrane module productivity and high selectivity are critical for cost-efficient CO2 capture. High selectivity reduces the energy cost of CO2 capture while high module productivity reduces the capital cost of the membrane system. The proposed hybrid CO2 capture process concept couples the unique high performance membrane with cryogenic processing technology to efficiently capture at least 90% of the CO2 in the flue gas from an air fired power plant. This paper describes a successful long-term (8 month) test of the enhanced CO2 separation capability of the Air Liquide membrane at low temperatures. This demonstration was carried out with commercial scale membrane modules using a synthetic CO2/N-2 feed and is an important milestone in development of the cold membrane process. The membrane selectivity and permeance validated through bench scale testing was fed into with process simulation studies coupled with process equipment cost estimates. These results indicate that the cold membrane process concept is promising for CO2 removal from flue gas generated by coal power plants. (C) 2013 The Authors. Published by Elsevier Ltd. Open access under CC BY-NC-ND license. Selection and/or peer-review under responsibility of GHGT