Input on the Measurement and Comprehension of CO2 Solubility in Molten Alkali Carbonates in View of Its Valorization

Abstract

As the capture and valorization of CO2 in molten carbonates is nowadays becoming a strategic energy topic, the need of accurate solubility measurements of such molecule is becoming compulsory. This study provides a new set of reliable CO2 solubility values, determined by a a carefully adapted manometric setup, in Li2CO3-K2CO3 (62:38 mol%), Li2CO3-Na2CO3 (52:48 mol%), Li2CO3-Na2CO3-K2CO3 (43.5:31.5:25.0 mol%) and Na2CO3-K2CO3 (56:44 mol%) carbonate eutectics in an overall range of temperatures from 450 to 850 °C. High solubility values are obtained for Li-K and Li-Na eutectics, respectively 1.7 × 10−1 and 1.1 × 10−1 mol atm−1 l−1 at 650 °C. It is shown that CO2 solubility increases with the temperature for most of the eutectic mixtures. Another important trend is that the Li content significantly increases the solubility.