New concept on air separation

A new process which combines oxygen permeable membrane with oxygen absorbent was proposed to simultaneously produce pure oxygen and nitrogen from air. In the process, air is fed in the oxygen permeable membrane, and a large part of oxygen permeates through the membrane. Then, the oxygen-depleted air (similar to 7% O-2) passes through an oxygen absorption bed to make the residual oxygen absorbed; simultaneously, pure nitrogen is produced at the exit of the absorption bed. After the absorption bed reaches its saturated capacity, the oxygen-depleted air pass through another absorption bed switched by an automatic 3-way valve; at the same time the saturated absorption bed is under a desorption process by vacuum to renew the absorption capacity. The pumped out oxygen has a high-purity due to the oxygen absorbent is 100% selectivity to oxygen. As a result, nearly 100% recoveries of oxygen and nitrogen, and >99.4% oxygen purity and >99.0% nitrogen purity was achieved simultaneously. (C) 2008 Elsevier B.V. All rights reserved.