Process Optimization-Based Screening of Zeolites for Post-Combustion CO2 Capture by Vacuum Swing Adsorption

A total of 119 661 hypothetical zeolites, 1031 zeolite immidazolate frameworks, and 156 zeolites identified by the International Zeolite Association are screened for their effectiveness as adsorbents for postcombustion CO2 capture from a dry flue gas using vacuum swing adsorption. A batch adsorber analogue model is used to identify materials that meet the target CO2 purity of 95% and recovery of 90%. The screening indicates a minimum Henry's selectivity of 13 is required to meet these targets. The lowest energy consumption adsorbents showed CO2 and N-2 heats of adsorption in the ranges of -32 to -42 kJ/mol and -8 to -17 kJ/mol, respectively. Low N-2 affinity, more than high CO2 affinity, is the characteristic of low energy consuming adsorbents. A total of 15 top performers from the screening and 24 synthesizable zeolites were optimized for low parasitic energy using a detailed process optimization. The best adsorbent showed a 16% lower energy consumption compared to the current benchmark, Zeolite 13X.