Thermodynamics Research Center / ThermoML | Journal of Chemical Thermodynamics

ABSTRACT

In the present work, the equilibrium solubility of carbon dioxide (CO2) in aqueous amine mixture solutions of 2-((2-aminoethyl)amino)ethanol (AEEA) and N-methyldiethanolamine (MDEA) is measured in the temperature range of 308.2 K to 368.2 K and the pressure range of 101 kPa to 4448 kPa. The (vapor + liquid) equilibrium of binary AEEA and water system is measured at constant pressure of 86.6 kPa. The dielectric constant of AEEA is also obtained experimentally in the temperature range of 293.2 K to 348.2 K. For thermodynamic modeling the electrolyte modified Peng-Robinson cubic plus association equation of state (emPR-CPA EoS) [A.T. Zoghi, F. Feyzi, M.R. Dehghani, Ind. Eng. Chem. Res. 51 (2012) 9875 9885] is applied and the solubility of CO2 in the aqueous mixture of AEEA and MDEA is obtained. In order to model the quaternary system, parameters of the emPR-CPA EoS are first adjusted for pure components. Then, the binary molecular interaction parameters for binary sub systems (CO2 Water, CO2 MDEA, CO2 AEEA, MDEA Water, AEEA Water) and the ionic interaction parameters for ternary sub systems (MDEA CO2 Water) and (AEEA CO2 Water) are optimized. By the emPR-CPA EoS the CO2 solubility is obtained in the ternary sub-systems (MDEA CO2 Water) and (AEEA CO2 Water) with average absolute percent deviations (AAD%) equal to 17.32 and 14.63, respectively. Finally, the equilibrium solubility of CO2 in aqueous mixture of AEEA + MDEA is obtained with AAD% = 24.3 and root mean square relative deviation percent (RMSD%) = 27.67.