262291 Mass Transfer Evaluation of CO2 Absorption in a Wetted Wall Column

Thursday, November 1, 2012: 3:35 PM
301 (Convention Center )
Reynolds A. Frimpong, Joseph E. Remias, James K. Neathery and Kunlei Liu, Center for Applied Energy Research, University of Kentucky, Lexington, KY

The chemical absorption of CO2 in solvents is considered as one of the mature process options for reducing CO2 emissions in power plants. Solvents with fast mass transfer rates and high CO2 carrying capacity are therefore desired and continue to be explored to reduce equipment size and its associated capital cost. The wetted wall column provides a relatively facile assessment of solvent mass transfer characteristics and was used in this study to analyze the performance of 30 wt% monoethanolamine (MEA) for CO2 absorption at utility flue gas concentrations that will pertain over the height of an absorber in post-combustion CO2 capture process.

In this work, different CO2 gas concentrations were absorbed by MEA at various carbon loadings and the flux measured. The overall mass transfer of CO2 into MEA was evaluated by considering the relative contributions of the gas and liquid side resistances. The applicability of the pseudo-first order approximation and the instantaneous reaction were assessed for the different conditions to determine the appropriate reaction regimes. It was determined that at lean solvent conditions with low driving force (representative of conditions at the top of an absorber), mass transfer was well modeled by the pseudo-first order approximation.

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