Physical properties and reaction kinetics of CO2 absorption into unloaded and CO2 loaded viscous monoethanolamine (MEA) solution

Abstract

In order to comprehensively understand how solvent free concentration and high viscosity affect mass transfer and consequently absorption flux, CO2 absorption kinetics into unloaded and CO2 loaded viscous monoethanolamine (MEA) solution were studied in this work using the string of discs contactor. Moreover, density and viscosity of unloaded and loaded viscous MEA solutions were measured using an Anton Paar DMA 4500 density meter and an Anton Paar Lovis 2000 ME rolling-ball viscometer, respectively, and the results were correlated using Redlich-Kister and modified Vogel-Tamman-Fulcher equations as a function of temperature, concentration and CO2 loading. Overall mass transfer coefficients of CO2 absorption in viscous MEA solution were measured over a wide temperature range of 298.15 to 343.15 K and CO2 loading in the range of 0 to 0.4 (mol CO2/mol MEA). A simplified kinetic model was applied to interpret the mass transfer data and explain reaction kinetics between CO2 and unloaded and loaded viscous MEA solution. The effect of temperature, CO2 loading and viscosity on second order reaction rate constant and overall mass transfer coefficients was also discussed.