Kinetics and Thermodynamics of CO2 Absorption in Aqueous 3-Dimethylaminopropylamine and Its Blend with Poly(ethylene glycol) Dimethyl Ether Using a Wetted Wall Column Reactor

Biphasicsolvent 3-dimethylaminopropylamine (DMAPA)/poly-(ethyleneglycol) dimethyl ether (NHD)/H2O solution is a promisingabsorbent for CO2 capture. The kinetics of CO2 absorption in both DMAPA/NHD/H2O system and DMAPA/H2O systems was investigated and compared in a wetted wall columnreactor with different CO2 loadings at different CO2 partial pressures from 30 to 70 degrees C. The equilibriumCO(2) loadings were also determined. Meanwhile, the densityand viscosity for both systems were measured. In both systems, themass transfer flux of CO2 increases linearly with the increaseof CO2 partial pressure. The kinetic data were interpretedby the zwitterion mechanism. The overall mass transfer constant wasdetermined according to the absorption rate experiments performedin the pseudo-first-order regime. The overall mass transfer resistancesincrease with the increase of CO2 loading and decreasewith the increase of temperature. The addition of NHD decreases theequilibrium CO2 loadings at the same CO2 partialpressure and temperature. However, it increases the enhancement factorsignificantly and can promote both the absorption and the desorptionprocess. It provides basic information not only for the further utilizationof DMAPA/NHD/H2O solution, which is helpful for the designof absorption reactor, but also for developing new phase-change absorbentsfor CO2 capture.