A simplified semi-empirical model for modeling of CO2 solubilities in aqueous MDEA and MEA solutions

A simplified semi-empirical model was developed for modeling of carbon dioxide (CO 2 ) solubility in aqueous solutions of methyldiethanolamine (MDEA) and monoethanolamine (MEA) with a temperature range from 283.15 K to 393.15 K, and alkanolamine molarity (1–5) mol/L. This model accounts for chemical equilibria in the liquid phase and physical equilibria between the liquid and vapor phases, which can calculate the vapor liquid equilibria (VLE) of MDEA+H 2 O+CO 2 system and MEA+H 2 O+CO 2 system. This paper proposes a Simplified Kent-Eisenberg Model (SKEM) to describe the chemical equilibria in amine – acid system, which is built with the conception of ion pairs meets the like-ion repulsion assumption and the local electroneutrality assumption. In the physical equilibria, the Henley coefficient was refitted using a new correlation, which was built with the combinations of sines and cosines. Adjustable parameters of the SKEM model, representing chemical equilibrium constant including activity coefficients, were determined by data regression with 187 sets of data of MDEA+H 2 O+CO 2 system and MEA+H 2 O+CO 2 system. The SKEM model has a good predictive ability, the Absolute Average Relative Deviations (AARD) of predicted results of SKEM model in MDEA+H 2 O+CO 2 system and MEA+H 2 O+CO 2 systems are 13.66% and 8.33%, respectively.