Measurement and Correlation of the Solubility of Carbon Dioxide in the Mixtures of Aqueous Monoethanolamine Solution and Benzoic Acid

Abstract

The solubility of CO2 in the mixture of aqueous monoethanolamine (MEA) with benzoic acid was measured and correlated using a reaction-phase equilibrium model. The solubility of CO2 in 15 wt % aqueous MEA solution was measured at a temperature of 313.2 K and pressures up to 200 kPa. Also, the solubility of CO2 in the mixtures with various weight ratios of benzoic acid, MEA, and water were measured at a temperature of 313.2 K and pressures ranging from (1 to 250) kPa. The weight ratios (acid/MEA/water) were 1:15:85, 2:15:85, 10:15:85, 15:15:85, 1:14:85, 2:13:85, and 5:10:85. Reaction equilibrium constants of the Kent-Eisenberg model were used for the CO2-MEA-water mixture, and new equilibrium constants involving benzoic acid were estimated using experimental data. The concentration of species in the liquid phase was estimated as a function of CO2 loading, and the effect of adding benzoic acid can be predicted within reasonable accuracy using the proposed model.