| 摘要 |
In a process for the separation and purification of oxygen and nitrogen a membrane containing in solution a metallo-organic oxygen carrier capable of reversibly binding molecular oxygen is utilised to selectively transport oxygen from one gaseous stream (feed stream) to another, leaving nitrogen as a byproduct when the feed stream is atmospheric air. The membrane separates the gaseous feed stream such as atmospheric air and the gaseous product stream. The feed stream is maintained at a sufficiently high oxygen pressure to keep the oxygen carrier in its oxygenated form at the interface of the feed stream with the membrane, while the product stream is maintained at sufficiently low oxygen pressure to keep the carrier in its deoxygenated form at the interface of the product stream with the membrane and/or the feed stream is maintained at a sufficiently low temperature and high oxygen pressure to keep the oxygen carrier in its oxygenated form at the interface of the feed stream with the membrane and the product stream is maintained at a sufficiently high temperature to keep the carrier in its deoxygenated form at the interface of the product stream with the membrane. Under such conditions the carrier acts as a shuttle, picking up oxygen at the feed side of the membrane, diffusing across the membrane as the oxygenated complex, releasing oxygen to the product stream and then diffusing back to the feed side to repeat the process. Exceptionally and unexpectedly high O2/N2 selectivity, of the order 10 to 30, is obtained, as well as exceptionally high oxygen permeability, of the order of 6 to 15 x 10<-><8> cm<3> -cm/cm<2>-sec-cmHg, as well as a long membrane life of in excess of 3 months, making the process commercially feasible. |
