Solubility of Carbon Dioxide in Aqueous Potassium Salts of Glycine and Taurine at Absorber and Desorber Conditions

Abstract

In this work the vapor liquid equilibria (VLE) of carbon dioxide in both taurine (KTaurate) and glycine (KGlycinate) potassium salts are measured and compared to literature data. The VLE data were measured at two salt concentrations of approximately (1 and 1.8) mol·kg–1, and at temperatures of (313, 333, 353, 373, and 393) K. The experiments were carried out in three different stirred cell reactors, all operated in batch mode to ensure the highest accuracy. The experimental results show that the CO2 partial pressure for the same loading is higher in all cases for KTaurate compared to KGlycinate. Experiments showed higher acid gas partial pressures for higher concentrations at the same temperature. Furthermore, for both solvents at 373 K the relative difference in CO2 partial pressure is greatest with a factor 2 for two solutions with the same loading. KGlycinate at 393 K showed significant degradation observed through color change and formation of gas with approximately 3 % AAS conversion in 2.5 days for a concentration of 1.7 mol·kg–1.