Rapid screening of CO2-selective zeolites, carbons and MOFs by Five-step vacuum swing adsorption performances estimated with equilibrium theory analysis

• Various CO2-selective adsorbents including zeolites, carbons and MOFs were evaluated. • Adsorbents were ranked with respect to CO2 recovery and bed productivity of CO2 capture VSA. • Bespoke Equilibrium Theory analysis for five-step VSA system was utilised for evaluation. It was aimed to evaluate a variety of conventional and emerging CO 2 -selective adsorbents, considering their use in a five-step VSA (Vacuum Swing Adsorption) system for flue gas capture. In most works, porous materials synthesised for CO 2 capture were assessed by simply comparing their gas adsorption capacities measured at fixed pressures, without considering how they would perform in cyclic adsorption processes. Meanwhile it would be so laborious to conduct full numerical simulations of adsorption processes for evaluating and screening a number of adsorbents. In this study, zeolites, carbons and MOFs synthesised for CO 2 capture were assessed and ranked with respect to the CO 2 product recovery and the bed productivity of a five-step VSA, with an Equilibrium Theory model developed for the adsorption process. The simplified VSA model can provide the results so quickly, requiring only the adsorbent’s pure component adsorption isotherms in solving it. According to the simplified model, the CO 2 recovery hinges upon the process operating conditions, i.e. adsorption-to-desorption pressure ratio and feed composition as well as equilibrium adsorption isotherms, i.e. the shape of CO 2 isotherm and adsorbent’s selectivity of CO 2 over N 2 . The bed productivity is influenced greatly by adsorbent’s CO 2 adsorption capacity, also affected by the VSA’s CO 2 recovery and adsorbent’s CO 2 selectivity.