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Kinetics of Carbon Dioxide Absorption into Water-Lean Potassium Prolinate/Ethylene Glycol Solutions

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journal contribution
posted on 16.05.2019, 00:00 by Hui Li, Shufeng Shen
Kinetics of the reaction of carbon dioxide (CO2) with potassium prolinate (ProK) in water-lean ethylene glycol was measured using a stirred cell reactor at temperatures from 283.2 to 313.2 K with ProK concentrations ranging from 0.5 to 2.0 M. Physicochemical properties including Henry’s constant of N2O and CO2 were measured or estimated for the investigated solutions. A proposed correlation was used to calculate the liquid-side physical mass transfer coefficient. The observed reaction rate constants (kobs) were obtained from the measured absorption flux against CO2 partial pressure under the pseudo-first-order regime conditions. Results show that the overall pseudo-first-order rate constant kov increases remarkably as the increasing ProK concentration and temperature. The reaction order with respect to ProK is found to vary between 1.76 and 1.91 over the temperature range, which is quite different from that observed in aqueous ProK systems. The kinetic results were also nonlinearly regressed to fit the models based on zwitterion mechanism and termolecular mechanism. The expression for the rate of CO2 absorption was proposed as a function of the temperature and ProK concentration for the experimental conditions studied.