Modeling of H₂S, CO₂ + H₂S, and CH₄ + CO₂ Solubilities in Aqueous Monoethanolamine and Methyldiethanolamine Solutions

The extended UMR-PRU (eUMR-PRU) model is used in this work to describe the solubilities of H 2 S and mixed acid gases (H 2 S + CO 2 ) in aqueous monoethanolamine (MEA) and methyldiethanolamine (MDEA) solutions. Moreover, the effect of methane on the solubility of CO 2 in aqueous MDEA solutions is examined. For the chemical equilibrium description, the equations of the mole fraction-based equilibrium constants are solved simultaneously with mass balance and electroneutrality equations. For the vapor–liquid equilibrium calculations, the eUMR-PRU model is applied after the determination of the missing interaction parameters. The eUMR-PRU model is compared to other widely used models, namely, the Kent–Eisenberg model and the electrolyte NRTL model. It is shown that the eUMR-PRU results are in satisfactory agreement with the experimental data and similar to those obtained by other models.