Modeling and Comparative\nAnalysis of CO<sub>2</sub> Absorption Columns in Electrochemical and\nThermochemical Carbon\nCapture Systems

Deployment of post-combustion carbon dioxide (CO<sub>2</sub>) capture\ntechnologies is needed to reduce emissions from power and industrial\nsources. Comparisons between existing thermochemical CO<sub>2</sub> capture methods and emerging electrochemical concepts can help contextualize\nthe promise of these new approaches. Here, we investigate the required\nabsorber sizes for three capture systems: amine scrubbing using monoethanolamine\n(MEA), direct electrochemical (redox-active sorbent), and indirect\nelectrochemical (pH swing). For the electrochemical systems, we study\nhow column size varies as a function of molecular properties and operating\nconditions, finding that parameters most closely related to CO<sub>2</sub> uptake rates (i.e., rate constants and p<i>K</i><sub>a</sub>) have the greatest impact. Through a Monte Carlo analysis,\nwe find that the direct process can be designed to have column sizes\nsimilar to the thermochemical process; however, the CO<sub>2</sub> uptake rate in the indirect process is too slow to enable smaller\ncolumns. Broadly, this work connects system input parameters to absorber\nperformance for electrochemical CO<sub>2</sub> capture and provides\na foundation for techno-economic and engineering analyses.