Comparative kinetics of carbon dioxide absorption in unloaded aqueous monoethanolamine solutions using wetted wall and string of discs columns

Abstract

The kinetics of the reaction between carbon dioxide and unloaded aqueous solutions of monoethanolamine (MEA) were investigated over the temperature range from 298 to 343K, MEA concentration range from 0.5 to 5mol/L in both a wetted wall column reactor (WWC) and a string of discs contactor (SDC). Earlier kinetic studies in the CO2–MEA–H2O system are reviewed and compared first based on the experimental data alone. The comparisons are made for different types of apparatuses to establish whether the recent literature data and the data from this study are consistent with each other. Then the various ways of interpreting the data are reviewed and compared. Finally, the new data are interpreted using the pseudo first order assumption and including gas phase mass transfer resistance. The direct mechanism was used for the interpretation and the reaction order was found to be in the range of 1.36–1.51 with respect to concentrations. A model was developed for the kinetic rate constant explaining the broken order behavior.