Design, Fabricate and Functional Validation of a Wetted Wall Column for the study CO2 Absorption Kinetics

Abstract

To make carbon capture more economically viable, accurate CO2 absorption kinetics estimates for new solvents are essential: slow absorption kinetics require larger, more expensive reactors to compensate. Gas absorption kinetics are the result of both mass transport and chemical reaction kinetics, so process design decisions depend on understanding what is rate-limiting: slow mass transport is best compensated by changing the reactor’s fluid dynamics, whereas slow reaction kinetics are best addressed by changing the solvent chemistry. In this study, we designed a laboratory-scale wetted wall column (WWC), a reactor that provides a precise, known interfacial area to allow us to separate chemical kinetics from molecular mass transport to assist in solvent screening. We report the validation of the WWC using a standard solvent (NaOH), determining the second order rate constant from the measured CO2 absorption flux using established reactive thin film absorption relationships and comparing our measured rate constant to kinetic data from the literature. Successful validation confirms the WWC as a reliable tool for screening new solvents, thereby accelerating the search for more cost-effective carbon capture processes.