Carbon Capture and Storage (CCS) technologies applied to fixed CO2 sources are currently considered to be one of the most promising methods to reduce greenhouse gas emissions. CCS is based on the selective separation of CO2 in the industrial effluent by chemical absorption into solution. An advantage of this technology is that it can be integrated into existing industrial sites without major facility modifications. Capture processes are based on absorption/desorption cycles of gas in aqueous solvent solutions. The most usual absorbents are alkanolamines, which are already used for the deacidification of natural gas. The aqueous amine solutions loaded with CO2 are subsequently regenerated by desorption in a stripper, and the solvent is returned to the absorber. CO2 is then compressed and transported for further application or for secure storage. The main drawback of the technology is the extremely high cost linked to the energy expenses of the desorption/compression step. Moreover, future solvents should be designed as function of effluent specificity and, CO2 purity required for further valorization. The proposed project will combine the use of advanced molecular simulation methodologies, experimental measurement of physico-chemical properties and the development of robust thermodynamic models to provide key information on the molecular organization of such solutions and on their probable structure-property relationships. In the quest for improved solvents, the combination of those three scientific dimensions will enable the ability to provide clear and well-defined goals for the development of the processes on industrial scales. This project provides a synergistic collaboration between French and Canadian laboratories in joining their unique skills to describe in a realistic way the interactions involved in the water-amine-CO2 systems of interest.

Carbon dioxide (CO2) Capture from post-combustion industrial effluents will substantially contribute to the reduction of anthropogenic emission of carbon responsible for global warming. The chemical absorption of CO2 in mixed solvents (typically aqueous solution of alkanolamines) is considered as a promising avenue for its capture before transportation to a site of storage. The regeneration of the solvent is, however, costly since it requires substantial heating of the whole system containing the products resulting from chemical reactions of CO2. To reduce the cost of the capture process it is therefore considered to use instead aqueous solutions of amines that phase separate at moderately elevated temperatures. Such a phase separation occurring at the output of the absorber unit will concentrate carbon in water rich phase that is the only part of the solvent that needs to be regenerated. This project proposal focuses on the fundamental study of physico-chemical and engineering properties of binary and ternary systems containing these promising amines for future capture processes. The study should contribute to elucidate structure-properties relationships in order to design suitable demixing amines for CO2 absorption. It is proposed to investigate a group of piperidine derivatives and to analyse namely the effect of substitution by alkyl and/or aryl groups in different positions on the ring. The thermodynamic measurements (CO2 solubilities and liquid-liquid equilibria, solution and mixing enthalpies, excess molar heat capacities and volumes) will be performed mainly in the laboratory Thermodynamics and Molecular Interactions at the Institute of Chemistry of Clermont-Ferrand (Blaise Pascal University) while the Raman spectroscopy performed at the Hydrothermal Chemistry Group of the University of Guelph will bring new information on the speciation of the absorbed carbon in amine solutions and in coexisting phases after demixing. These complementary measurements over an extended range of temperatures will be predominantly carried out on unique experimental instruments constructed in the partnering laboratories. The obtained thermodynamic data in combination with those characterizing the speciation will then allow adjustment of parameters in models suitable for description of this type of systems and to test their performance in extrapolations and predictions. The Canadian laboratory will work in association with an industrial partner, Gas Liquid Engineering Ltd, who will provide guiding facilitating future moving of the new technology from the laboratory to the industrial world.