Prediction of MOF Performance in Vacuum Swing Adsorption Systems for Postcombustion CO Capture Based on Integrated Molecular Simulations, Process Optimizations, and Machine Learning Models.
Journal:
Environmental science & technology
Published Date:
Apr 7, 2020
Abstract
Postcombustion CO capture and storage (CCS) is a key technological approach to reducing greenhouse gas emission while we transition to carbon-free energy production. However, current solvent-based CO capture processes are considered too energetically expensive for widespread deployment. Vacuum swing adsorption (VSA) is a low-energy CCS that has the potential for industrial implementation if the right sorbents can be found. Metal-organic framework (MOF) materials are often promoted as sorbents for low-energy CCS by highlighting select adsorption properties without a clear understanding of how they perform in real-world VSA processes. In this work, atomistic simulations have been fully integrated with a detailed VSA simulator, validated at the pilot scale, to screen 1632 experimentally characterized MOFs. A total of 482 materials were found to meet the 95% CO purity and 90% CO recovery targets (95/90-PRTs)-365 of which have parasitic energies below that of solvent-based capture (∼290 kWh/MT CO) with a low value of 217 kWh/MT CO. Machine learning models were developed using common adsorption metrics to predict a material's ability to meet the 95/90-PRT with an overall prediction accuracy of 91%. It was found that accurate parasitic energy and productivity estimates of a VSA process require full process simulations.