Abstract—The effect of mixing a tertiary amine, N,N-Methyldiethanolamine (MDEA), with a secondary amine, diethanolamine (DEA), on the kinetics of the reaction with carbon dioxide in aqueous media has been studied in a stirred cell reactor with a plane, horizontal gas-liquid interface. Temperature was varied from 293 to 313K over a range of blend composition and total mixture concentration ranging from one to two molars. The proposed model representing the reaction of CO
2 with the blends studied is found to be satisfactory in determining the kinetics of the involved reactions. This model is based on the zwitterion mechanism for the DEA and water hydration catalysis for MDEA. Blending MDEA with DEA results in observed pseudo-first-order reaction rate constant values (ko) that are greater than the sum of the ko values of the respective single amines. This is due to the role played by MDEA in the deprotonation of the zwitterion of the other amine (DEA). Species concentration profile needed to fit the experimental data to the model to extract the kinetic parameters associated with the reactions was calculated using the modified Deshmukh-Mather model.
Index Terms—Methyldiethanolamine, diethanolamine, absorption, carbon dioxide, kinetics.
The authors are with Gas Processing Center, Faculty of Engineering, Qatar University, Box 2713 Doha, Qatar (e-mail: benamor.abdelbaki@qu.edu.qa, m.almarri@qu.edu.qa).
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Cite: Abdelbaki Benamor and Mohammed Jaber Al-Marri, "Reactive Absorption of CO2 into Aqueous Mixtures of Methyldiethanolamine and Diethanolamine," International Journal of Chemical Engineering and Applications vol. 5, no. 4 pp. 291-297, 2014.
