Kinetics of CO2 Absorption in to Aqueous MEA Solutions Near Equilibrium

Abstract

Activity based reaction kinetic model, with the ability to predict the CO2 absorption rates close to equilibrium, is developed for CO2-aquoues MEA system using mathematical model developed using Penetration mass transfer theory. The non-linear partial differential equations are solved using orthogonal collocation method on finite elements (OCFE) and implemented in MATLAB software. The global optimization technique is used to obtain the optimized kinetic constants. The developed kinetic model is validated with experimental data from independent sources. The developed activity based kinetic model predicted the CO2 absorption rates with AARD of 13% for data from wetted wall column and laminar jet absorber with CO2 loadings 0.2 – 0.5 and temperatures 293-343K. The base contributions from carbonate and bicarbonate species for carbamate formation was found to be negligible compared to contributions from MEA and H2O. Carbamate reversion reaction has negligible effect on the model predictions even at high CO2 loadings.