Protonation constants of amino acid salts at 298-353 K

Since there is no flue-gas desulfurization facility (FGD) in Australian Power Plants, the temperatures of flue gases from the plants range from 393–433 K which is much higher than the absorption temperatures in a typical post combustion CO2 capture (PCC) process. The additional cooling systems and equipments are required to cool flue gases. This adds to the cost, and water and energy consumption, of PCC. Amino acid salts have potential for use as a high-temperature absorbent for CO2 capture, because of their low volatility, high absorption rate and high thermal stability. The CO2 absorption rate and CO2 solubility of amino acid salts are highly depended on the basicity of the salts, which can be expressed by protonation constant, pKa. However, the pKa of amino acid salts reported in literature was only determined at ambient temperature. In this study, the pKa of 11 amino acid salts has been determined in the temperature range of 298-353 K. KeywordsCO2 capture, amino acid salts, protonation constants