Kinetics of Carbon Dioxide Absorption into Mixed Aqueous Solutions of MEA + [Bmim]BF₄ Using a Double Stirred Cell

Abstract

An aqueous blend of monoethanolamine (MEA) and 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim]BF4) for CO2 absorption from simulated flue gas was investigated using a double stirred cell at a CO2 partial pressure of 15 kPa. It was found that the values of the enhancement factor (E) and the second-order reaction rate constant (k 2,mix) for CO2 absorption into mixed solution were higher than those into a single MEA aqueous solution with the same MEA concentration. k 2,mix and k 2, IL were found to be 3487.6 m3·kmol–1·s–1 and 1936.7 m3·kmol–1·s–1 at 303.15 K, respectively. The Arrhenius equation of CO2 absorption was also estimated. The results proved the assumption that [Bmim]BF4 had an active effect on the CO2 hydration. The diffusion and solubility of the absorbent in the solution were the limiting factors of the reaction.

Kinetic performance of CO2 absorption into a potassium carbonate solution promoted with the enzyme carbonic anhydrase: Comparison with a monoethanolamine solution

“…4, the rates of CO 2 absorption into the MEA solutions with different CO 2 loading levels differed substantially. The value of k MEA decreased from 6200 to 2000 L mol À1 s À1 when the CO 2 loading was increased from 0.2 to 0.45 mol CO 2 /mol MEA, which was of the same order of magnitude as the kinetic data reported in the literature [7,32]. The trend of a decreasing rate constant with an increase in CO 2 loading in the MEA solvent was also observed in the literature [32].…”

“…Because deprotonation of the zwitterion is instantaneous, the reaction of CO 2 with MEA is of the first order with respect to both CO 2 and MEA. The reported rate constant of the CO 2 -MEA reaction has ranged between 4.0 Â 10 3 and 9 Â 10 4 L mol À1 s À1 , depending on the reaction conditions (e.g., temperature and MEA concentration) [7,8]. Most of the above-mentioned studies have been performed at low-temperature conditions (25-40°C), at a low MEA concentration (0.02-2 M), and with a fresh MEA solution, all of which are much different from those of the typical practical process.…”

Gas–liquid mass‐transfer properties in CO2 absorption system with ionic liquids

“…The liquid-side mass-transfer coefficient obtained in the IL-H 2 O systems was applied to determine E in the MEA-IL-H 2 O systems. Similar approximation has been reported in different research groups, 32,[45][46][47] who used water as liquid phase to determine k L in studying the kinetics of CO 2 chemical absorption into different amine aqueous systems. The available k L values of absorbing CO 2 in water and in IL have been presented in Table 5.…”

Ionic liquids tailored amine aqueous solution for pre-combustion CO2 capture: Role of imidazolium-based ionic liquids

“…(17) and measured solubility of N 2 O in amine-RTILs solvents with temperature from about 299 K to 339Kare presented in Fig. 6.…”