Communication à un colloque
Résumé : The gas-liquid carbon dioxide (CO2) absorption by aqueous solutions of amine mixture is one of the up-to-date CO2 capture technology. This work is realized in collaboration with Cansolv Technologies Inc., which is a design office specialized in the development of amine solutions for CO2 scrubbers. These solutions consist in various mixtures of several amines, which combine a fast reaction rate with the CO2, a high absorption capacity, a high stability and a low energetic regeneration cost. An accurate identification of the gas-liquid CO2 absorption kinetic parameters is required to select the best amine mixture. Besides, this identification is necessary to design the scrubbers. This work deals with the development of an original experimental method to identify the gas-liquid CO2 absorption parameters in aqueous amine solutions. The monoethanolamine (MEA) is used as a reference case, as physico-chemical parameter values and reaction kinetic models can be found in the literature. The absorption of pure gaseous CO2 in an aqueous MEA solution is realized in Hele-Shaw cell. During this absorption, chemical reactions occur in the solution. Small refractive index variations of the liquid phase take place in the vicinity of the gas-liquid interface and are observed using a digital holographic Mach-Zehnder interferometer. A calibration curve is determined using a refractometer, by measuring the refractive index of MEA solutions for various dissolved CO2 amount. The calibration curve allows comparing the experimental profiles with numerically simulated refractive index profiles, which are computed using a penetration model in a semi-infinite liquid phase. The physico-chemical parameters are identified by fitting the simulated refractive index profiles to the experimental ones, considering the same operational conditions, using a parametric least-square fitting method. A good agreement between the simulated and the experimental profiles is obtained with the fitted parameter values and it is observed that these values are close to those referenced in the literature. Therefore, the developed procedure is applied to study the gas-liquid CO2 absorption parameters in a solvent provided by Cansolv.