Kinetics research on mixed solvents of MDEA and enamine in natural gas decarbonization process

• The kinetics model was established and fitted to the experimental data.
• Kinetics model of single MDEA system was compared with the mixed amine system.
• When absorption rate was slower, the reaction was close to be pseudo first order.
• The interaction of different amines obviously affected the accuracy of kinetics model.

Mixed amine solvents have become research trend as their great performance of decarbonization in recent years. The kinetics model was established and fitted to the experimental data. Then the reaction kinetics of mixed solvents of MDEA and enamine in CO2 absorption process were analyzed through model. The results showed that the optimum concentration of absorbent and operating temperature exists in single MDEA system. As for mixed amine systems, the CO2 absorption capacity was stronger as the DETA or TETA dosages were greater. The model prediction accuracy for single MDEA solvent was better while the model prediction accuracy for 2.0 MDEA/1.0 DETA was decreased. When absorption rate was slower, the reaction was more close to the pseudo first order, and then the prediction accuracy of the model was higher. The research in this paper can promote the industrial applications of mixed amine solvents.