Identification of metal-organic frameworks for near practical energy limit CO2 capture from wet flue gases: an integrated atomistic and process simulation screening of experimental MOFs

Metal-organic framework (MOF) materials have attracted significant attention as solid sorbents for low energy CO2 capture with adsorption-based gas separation processes. In this work, an integrated screening workflow combining a series of atomistic and process simulations was applied to identify promising MOFs for a 4-step pressure-vacuum swing adsorption (P/VSA) process at three different CO2 flue gas compositions (6%, 15% and 35%). Starting from 55,818 unique experimentally characterized MOFs, ~19k porous MOFs were investigated via atomistic grand canonical Monte Carlo (GCMC) simulations and process optimizations. Thousands of MOFs were identified for each of the CO2 compositions tested that could achieve within 4% of the practical energy limit of dry CO2 capture for the P/VSA process while still meeting the 95% CO2 purity and 90% recovery constraints. From this pool, 526, 536 and 1,527 MOFs were subjected to the multi-component (CO2/N2/H2O) GCMC simulations at 40% relative humidity. Based on these simulations, hundreds of MOFs were identified at each CO2 composition that could retain 90% of their CO2 capture at this humidity while also adsorbing a minimal amount of water. A geometric analysis of these high performing materials revealed that narrow, straight 1D-channels, were a common structural motif for low energy wet flue gas CO2 capture with P/VSA.