CO2 capture by vacuum swing adsorption: role of multiple pressure equalization steps

Abstract

The performance of a 4-bed/16-step vacuum swing adsorption cycle containing three pressure equalization (PE) steps has been analysed in order to understand the role played by the multiple PE steps in the process performance. The cycle was designed for CO2 capture from a feed gas mixture of 15 %CO2/85 %N2, with zeolite ×13 adsorbent from UOP (PSO2HP). Simulations were performed with the help of the commercial Aspen Adsorption simulator to help interpret the experimental results. It was found that CO2 loading decreased only slightly, but N2 loading decreased significantly and uniformly across the bed after each PE step. Thus, while CO2 working capacity remained almost constant, working selecti..