Abstract 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. A modified duplex PSA has been presented to achieve process intensification, that is, to enhance the product purities and productivities. Simulation studies were carried out to explore the attainable product purities and possible process intensification for CO2 capture with the original and modified duplex PSA. The volume reduction of beds that can be realized with modified duplex PSA is about 100–50 times the original duplex PSA depending upon the product purities.