Identification of Metal–Organic Frameworks for near Practical Energy Limit CO <sub>2</sub> Capture from Wet Flue Gases: An Integrated Atomistic and Process Simulation Screening of Experimental MOFs
Ohmin Kwon, Marco Gibaldi, Kasturi Nagesh Pai, Arvind Rajendran, Tom K. Woo
Abstract
High Resolution Image Download MS PowerPoint Slide Metal–organic framework (MOF) materials have attracted significant attention as solid sorbents for low energy CO 2 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 CO 2 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 machine learning model-based process optimizations to accelerate the screening of a large candidate database. Thousands of MOFs were identified for each of the CO 2 compositions tested that could achieve within 4% of the practical energy limit of dry CO 2 capture for the P/VSA process while still meeting the 95% CO 2 purity and 90% recovery constraints. From this pool, 3D MOFs without open metal sites were subjected to the multicomponent (CO 2 /N 2 /H 2 O) GCMC simulations at 40% relative humidity. Based on these simulations, hundreds of MOFs were identified at each CO 2 composition that could retain 90% of their CO 2 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 CO 2 capture with P/VSA.