Liquid-liquid equilibriums in aqueous solutions of demixing amines loaded with gas for CO 2 capture processes

International audienceCarbon Capture and Storage (CCS) is a solid option for CO2 mitigation in the atmosphere. One option is the CO2 capture from industrial effluents followed by storage in secured sites. Capture processes are based on selective absorption/desorption cycles of gas in aqueous solutions of amines[1]. The cost of CO2 treatment with classical alkanolamines is a limitation for the use of this technology. The development of breakthrough technologies is needed to optimize the separation process. One of the considered option is the use of a new class of amine : the demixing amines. Those amines are going through a liquid-liquid separation phase when increasing the temperature[2]. This very interesting property allows to treat only a part of the absorbent solution for the regeneration of the CO2 in the absorption/desorption cycle. The use of such new system induced the perfect knowledge of the liquid-liquid equilibriums (LLE) in the binary mixtures water + amine, and the influence of the CO2 on such equilibriums. The aim of this paper is to present a method developed in the laboratory to study precisely the LLE in the binary solutions water + amines and the ternary mixtures water+amine+CO2, as a function of the pressure and the CO2 loading charge. This work is realized with the financial support of ANR and NSERC through an international collaborative project between France and Canada named DACOOTA

Thermodynamics of amide + amine mixtures. 5. Excess molar enthalpies of N,N-dimethylformamide or N,N-dimethylacetamide + N-propylpropan-1-amine, + N-butylbutan-1-amine, + butan-1-amine, or + hexan-1-amine systems at 298.15 K. Application of the ERAS model

Producción CientíficaExcess molar enthalpies, HEm, over the whole composition range have been determined for the liquid mixtures N,N-dimethylformamide (DMF) or N,N-dimethylacetamide (DMA) + butan-1-amine (BA), or + hexan-1-amine (HxA), or + N-propylpropan-1-amine (DPA), or N-butylbutan-1-amine (DBA) at 298.15 K and at 0.1 MPa using a BT2.15 calorimeter from Setaram adapted to work in dynamic mode at constant temperature and pressure. All the HEm values are positive, indicating that interactions between like molecules are predominant. The replacement of DMF by DMA in systems with a given amine leads to lower HEm results, which have been ascribed to stronger amide-amide interactions in DMF mixtures. The replacement of HxA by DPA in systems with a given amide leads to slightly higher HEm values, as interactions between unlike molecules are weaker for the latter. Structural effects in the investigated solutions are also present, since the corresponding excess molar volumes (VEm), previously determined, are negative or slightly positive. The systems have been characterized in terms of the ERAS model reporting the interaction parameters. The model correctly describes both HEm and VEm. The application of the model suggests that, in the systems under study, solvation effects are of minor importance and that physical interactions are dominant.Consejería de Educación, Junta de Castilla y León: Project VA100G19 (Apoyo a GIR, BDNS: 425389)Ministerio de Educación, Cultura y Deporte (MECD): Grant FPU14/04104Ministerio de Educación, Cultura y Deporte (MECD): Complementary Grants EST16/00824 and EST17/0029

Novel physico-chemical approach of post-combustion CO2 capture

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Thermodynamic properties of aqueous solutions at high temperature and high pressure. Bob Wood heritage

International audienceThe flow techniques used for measuring calorimetric and volumetric properties of liquid mixtures at room temperature were introduced by P. Picker at the beginning of the seventies. The results obtained using those techniques are of major interest in the study of aqueous solutions where the knowledge of thermodynamic properties of solutes at infinite dilution is needed [1]. Regarding aqueous solutions at high temperature and pressure, theoretical work done at Berkeley around 1980 by K. Pitzer [2] (theory of ionic interactions) and HC Helgeson [3] (HKF model) have strongly influenced the modeling of hydrothermal systems. They highlighted the usefulness of calculating activity coefficients by integrating derived thermodynamic properties of solutes (volume, enthalpy, heat capacity) available from calorimetric and densimetric measurements. The development of new devices then became a necessity and a challenge. RH Wood at the University of Delaware has been the pioneer in the implementation of flow techniques at super-ambient conditions [4] and his group made the first measurements of heat capacities and volumes of dilute solutions near to the critical point of water. After the "American period", more systematic work followed in the 90's trying to elucidate and quantify the behavior of aqueous solutions at HT/Hp conditions. Two instruments, unique in Europe, have been developed in Clermont-Ferrand in order to get derivative properties up to the critical point of water (T <700 K, p <40 Mpa) [5,6]. These devices will be described here in the context of experiments with aqueous systems containing electrolyte or non-electrolyte molecules. Examples will include volatile solutes, weak acids, lanthanides in water. Some results will be shown also concerning dissolution of gas (CO2) in aqueous solutions [7-9]

Thermodynamic properties of aqueous solutions: applications to greenhouse gas capture and storage

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Activities of CO2 capture group of Institut of Chemistry of Clermont-Ferrand

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Five decades of scientific achievments: my personal perspective on Pr Jean-Pierre GROLIER.

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CO2 Capture in Industrial Effluents.Calorimetric Studies

In order to reduce environmental impact of emissions, one possible option is the decarbonation of the effluents coming from fixed sources. A description of the different techniques proposed for a separation of from gaseous effluents is explained with a focus on post-combustion processes. The design of specific separation units will require studies of gas dissolution in various selective absorbent solutions. The thermodynamic approach for dissolution in aqueous solutions of amine is depicted, showing the physicochemical background and the main properties required in this domain. An overview of the main experimental developments for determining the enthalpy of solution of carbon dioxide in absorbent solutions is presented together with some representative results

THE USE OF CALORIMETRY FOR CARBON CAPTURE AND STORAGE (CCS) APPLICATIONS

communication oraleInternational audienceCarbon Capture and Storage (CCS) is one of the main options for CO2 mitigation. One option for industrial sites consist in post-combustion capture processes, followed by storage in secured sites. In the various options for industrial CO2 capture, the use of selective absorbents is considered as one of the most adequate methods [1]. The most current absorbents are the aqueous solutions of amine used already beneficially in the decarbonation of natural gases. The optimisation of the process goes through the rational use of energy and the choice of the amine, more capacitive and less energy consuming. The thermodynamic study of CO2 dissolution in such aqueous solutions allows the correlation and the prediction of absorption capacities and energy cost depending on amine structure and temperature, pressure and composition. These studies have to combine experimental measurements [2-4] and modeling developments [5-6]. This work will present the thermodynamic data experimentally accessible in our laboratory and necessary for the development of predictive models and for the optimization of the process. The properties essential for the understanding of CO2 dissolution (loading charge, enthalpy of dissolution, dissociation constants, excess enthalpies...) will be illustrated through some examples

Mesures d'enthalpies de mélange CO2 - Réfrigérant, concept et résultats

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