Equilibrium solubility of carbon dioxide in aqueous solutions of (diethylenetriamine + piperazine)

Abstract

In this study, we report new experimental measurements on the solubility of carbon dioxide in aqueous blended amine solutions containing diethylenetriamine (DETA) and piperazine (PZ) (at 30wt% total amine concentration). Solubility data for CO2 in aqueous DETA solutions at several concentrations (20,30,40)wt% are also presented. Measurements were performed in a vapor-liquid equilibrium apparatus at temperatures (313.2,333.2,353.2)K and pressures up to around 900kPa. It was found that the solubility of CO2 in the systems studied were appreciably higher than in typical amine solvents. A modified Kent–Eisenberg model was used to correlate the obtained solubility of CO2 (expressed as mole CO2 per mole amine) in the solvent with CO2 partial pressure, temperature, and amine concentration. The model gave satisfactory representations of the solubility data at reasonable average absolute deviations between the experimental and the calculated values (of CO2 partial pressures) of 16% and 17%, for the binary and ternary systems, respectively.