Strategy for understanding the thermophysical properties of the dissolution of CO2 in aqueous solutions of demixing amines
Résumé
Carbon Capture and Storage (CCS) is one of the main options for CO2 mitigation. Post-combustion capture processes using amines are considered as one of the most adequate methods for CCS [1]. However, the energetic cost of avoided CO2 is very high and must be significantly reduced. Thus, several research groups are presently interested in the identification of new solvents with the aim to reduce the cost of the regeneration step. The objective of this research is to study a new class of amines. Demixing amines have the singularity to undergo a liquid-liquid phase separation in aqueous solutions as a function of temperature, composition and CO2 loading charge. These compounds can be considered as new absorbents for CO2 capture. The new process using such demixing amines will require less energy in removing carbon dioxide from post combustion effluent [2]. An overview of the first thermophysical properties of demixing amines based on piperidine skeleton are reported. The specific amines investigated were N-methylpiperidine and 2-methylpiperidine. The liquid-liquid equilibria (LLE) were studied [3]. Excess molar volumes, heat capacities and enthalpies were also measured over the range of temperature where the amine is fully miscible in water. The enthalpies of solution and solubility limits of CO2 in binary solutions were finally determined using a flow calorimetric technique for the {CO2 - 2-methylpiperidine - water} system. Finally a presentation of the strategic program for the characterization of such systems will be shown. The objective of this collaborative project will be to understand the structure-properties relationships in {CO2 - substituted piperidine - water} systems, depending on the substitution of the amine.