Equilibrium Solubility of CO₂ in Aqueous Potassium Taurate Solutions:  Part 1. Crystallization in Carbon Dioxide Loaded Aqueous Salt Solutions of Amino Acids

Abstract

Crystallization of a reaction product was observed during the absorption of CO 2 in aqueous potassium taurate solutions at 298 K. The crystallizing solid was found to be the protonated amine. The critical CO 2 loading value at which crystallization occurred was measured for various amino acid salt concentrations. A simple relation between the critical CO 2 loading value, initial amino acid salt concentration, and solubility of the amino acid in water is established. This relation seems to hold well in predicting the critical CO 2 loading value for salts of amino acids other than taurine, for which Hook ( Ind. Eng. Chem. Res. 1997, 36, 1779) has recently published some qualitative experimental data. The influence of the formation of the solid reaction product during the absorption of CO 2 in aqueous potassium taurate solutions on the mass-transfer characteristics of a gas−liquid contactor was investigated semiquantitatively for a stirred reactor. In particular, the effect of the presence and absence of crystals in CO 2 -loaded solutions on the liquid-side volumetric mass-transfer coefficient was studied by carrying out physical N 2 O absorption experiments in CO 2 -loaded aqueous potassium taurate solutions.