Solubility of carbon dioxide in aqueous solutions of amino acid salts

Abstract

The solubility of CO(2) in aqueous solutions of potassium glycinate was measured in a stirred reactor, at temperatures from 293 to 351 K, for amino acid salt concentrations ranging between 0.1 and 3.0 mol dm(-3) and CO(2) partial pressures up to 6 x 10(4) Pa. CO(2) Solubility in potassium threonate 1.0 mol dm(-3) was also measured at 313 K. It was observed that amino acid salt solutions can be very interesting for CO(2) absorption purposes since they present considerably high absorption capacities. Nevertheless, CO(2) solubility in these solutions does not change significantly for temperatures between 293 and 323 K, which can be a draw back concerning the absorbent regeneration. Potassium glycinate solubility data were interpreted using the thermodynamically sound model proposed by Deshmukh and Mather [1981. A mathematical-model for equilibrium solubility of hydrogen-sulfide and carbon-dioxide in aqueous alkanolamine solutions. Chemical Engineering Science 36 (2). 355-362] and the empirical Kent and Eisenberg [1976. Better data for amine treating. Hydrocarbon Processing 55(2), 87-90] model.