Process intensification in duplex pressure swing adsorption

As an alternative to the pressure swing adsorption (PSA) based on the Skarstrom cycle or its variants, a novel two-bed PSA--called duplex PSA--has been proposed by Hirose and independently by Leavitt to get both products of high purities. Simulation and experimental studies on duplex PSA for CO2 capture indicate that CO2 can be enriched to 95 mol% of feed containing 20 mol% CO2 and 80 mol% N2. Kumar et al. proposed a modification to duplex PSA to enhance the product purity and productivity. The studies on the modified duplex PSA show that the product purities in excess of 99 mol% are feasible. In this work, simulation studies have been carried out to explore the attainable product purities and possible process intensification for CO2 capture with the original and modified duplex PSA and a 4-bed PSA. The studies indicate that it is possible to obtain both product purities in excess of 98.5mol%. Further, these studies show that, for a product purity of 95 mol% CO2, the volume reduction of beds that can be realized with modified duplex PSA is about 7 times when compared with 4-bed PSA and 125 times the original duplex PSA.