New Experimental Data of CO2 Solubility in an Amine Solvent

Carbon Capture, Utilization and Storage (CCUS) is a topic of interest for its relevance in decreasing the emissions to the atmosphere of CO2, a powerful greenhouse gas, related to the industrial production and power generation by fossil fuels. Aqueous amine solutions can be used as chemical solvents for this aim, though the high energy consumption and the related operating costs, their toxicity and the corrosion issues related to their use do not favor their application on the large scale. The research on novel solvents for CO2 removal, that could overcome the disadvantages of the traditional solvents, requires the analysis of phase equilibria of systems for which physical-chemical properties cannot be found in detail in the literature. In particular, the solubility of gases, mainly CO2, in the mixture to be considered, is fundamental to understand the suitability of a new species as solvent for chemical or physical absorption. With the aim of overcoming the issues due to the lack of experimental data on novel systems, an experimental unit has been installed at the Process Thermodynamics laboratory (PT lab) of Politecnico di Milano aimed at collecting data of solubility and diffusivity of gases into low volatile liquids that could be used as solvents for CO2 capture. A detailed specific experimental procedure has been defined and the unit has been firstly operated for validation, by collection of solubility data of CO2 into a 30% wt. MonoEthanolAmine (MEA) solvent, one of the most developed solvents already industrially used. Both the conditions of the absorption section and of the regeneration section, operating at different temperatures, have been considered. Then, the description of the equilibrium attained in the experimental unit has been carried out, taking into account different thermodynamic models and selecting the one best describing the system.