As an alternative to the Swar Pressure Adsorption (PSA) based on the Skarstrom cycle or its variants, a new two layer PSA - called PSA duplex - has been proposed by Hirose and independently by Leavitt to obtain both high purity products. A modified duplex PSA has been presented to achieve the intensification of the process, that is, to improve the product's purities and productivities. Simulation studies were conducted to explore achievable product purities and possible intensification of the CO2 capture process with the original and modified PSA duplex. The volume reduction of the beds which can be made with modified duplex PSA is approximately 100-50 times the original duplex PSA depending on the product's purity.