Vapor-liquid equilibria of acid gas-aqueous ethanolamine solutions using the PC-SAFT equation of state

Using the perturbed-chain statistical associating fluid theory (PC-SAFT), the vapor pressure, saturated liquid density, and heat of vaporization for monoethanolamine (MEA), diethanolamine (DEA), and methyldiethanolamine (MDEA) were calculated. PC-SAFT accurately described the properties of the pure ethanolamines along the coexistence curve. Then, the vapor-liquid equilibria (VLE) of the aqueous ethanolamine solutions were calculated by temperature-independent binary interaction parameters. Using the binary interaction parameters for the systems DEA + water, DEA + methanol, and methanol + water, the VLE of the ternary system DEA + water + methanol was predicted. The results indicated that PC-SAFT successfully described the equilibrium properties of the aqueous ethanolamine solutions. Finally, the solubilities of carbon dioxide and hydrogen sulfide in the aqueous ethanolamine solutions were predicted and compared to the experimental data. While no adjustable parameters were used, PC-SAFT reasonably described the solubility data.