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

Dissolution of sulfur dioxide and nitrogen monoxide in water

Sulfur dioxide (SO2) and nitrogen monoxide (NO) are some of the gas impurities present in the carbon dioxide (CO2) separated from fume using post combustion capture process. Even in a small amount, these impurities may have an impact on storage process development. The dissolution of such gases in aqueous phase is part of the studies carried out to develop processes and analyze the risks in case of geological storage. The enthalpies of solution of SO2 and NO in water were here investigated by calorimetry, using a flow calorimetric technique. The enthalpies of solution were determined at 323.15 K and 373.15 K for sulfur dioxide, and at 323.15 K for nitrogen monoxide. The experimental enthalpy data were used together with available solubility data to test thermodynamic models representative of vapor-liquid equilibrium.Ministerio de Educación, Cultura y Deporte (MECD): Grant FPU14/04104Project SIGARRR, funded by ANR-13-SEED-000

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

Thermodynamics of amine mixtures. Systems formed by alkyl-amine and ether, or N,N-dialkylamide, or ethanenitrile

Systems of the type linear primary or secondary amine + cyclohexane, or + polar (namely, linear or cyclic monoether, + 1,4-dioxane, + N,N-dialkylamide, or + ethanitrile) have been investigated using literature data, and by means of DISQUAC. Interaction parameters for the contacts amine/ether, amine/amide and amine/nitrile are provided. For a given contact, the QUAC interchange coefficients remain practically constant along each homologous series. A similar trend has been encountered in other many previous studies. DISQUAC correctly describes excess molar enthalpies, HmE, and vapour-liquid and solid-liquid equilibria of the studied mixtures and improves calculations on HmE from the UNIFAC (Dortmund) model. The experimental data have been used to determine the enthalpy of the interactions between unlike molecules, which are stronger in systems with N,N-dialkylamides or ethanenitrile than in mixtures with ethers. On the other hand, it is shown that HmE values of amine + C6H12 mixtures are closely related to the amine self-association, and that interactions between molecules of the polar compounds are determinant on HmE results of the mixtures amine + fixed polar compound or of the systems fixed amine + polar compound (no linear monoether). Structural effects are relevant in the di-n-butylamine + linear ether systems. The application of the Flory model reveals that orientational effects are rather weak in the investigated solutions. This is in agreement with previous studies on this type of mixtures using the ERAS model.Project VA100G19 (Apoyo a GIR), Castilla y Leon Regional Gran

Capture and storage of carbon dioxide: thermodynamic studies.

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Etude thermodynamique de solutions aqueuses d'amines démixantes pour le captage du dioxyde de carbone

L objectif de cette thèse est l étude thermodynamique des systèmes {amine eau} et {CO2 amine eau}. Les amines étudiées sont des amines démixantes qui ont la particularité de présenter une séparation de phase liquide-liquide en solution aqueuse en fonction de la température et du taux de charge en CO2. Ces composés sont considérés comme de nouveaux solvants potentiels pour le captage du CO2. Les séparations de phase liquide- liquide des systèmes {amine eau} ont été mises en évidence par calorimétrie et par une technique visuelle en utilisant un microcalorimètre (microDSCIII, Setaram) et une cellule d équilibre de phase (SPM20, Thar Technologies). Pour permettre la représentation thermodynamique des systèmes {amine eau}, les volumes molaires d excès, les enthalpies molaires d excès et les capacités calorifiques spécifiques ont été mesurés. Les enthalpies de mélange ont été déterminées avec une technique calorimétrique à écoulement. Le calorimètre employé est un BT2.15 de chez Setaram équipé avec une cellule de mélange développée au laboratoire. Les volumes molaires d excès on été déterminés à partir des mesures des masses volumiques obtenues avec un densimètre à tube vibrant. Les capacités calorifiques spécifiques ont été déterminées avec le microcalorimètre microDSCIII. Les enthalpies d absorption du CO2 dans les solutions aqueuses et les limites de solubilité ont été étudiées pour les amines présentant un intérêt pour le captage du CO2 avec une technique calorimétrique à écoulement utilisant un C80 de chez Setaram. La dernière partie de ce travail concerne le développement de modèle thermodynamique pour corréler les données mesurées. Les énergies de Gibbs des systèmes {amine eau} sont calculées en utilisant soit le modèle étendu UNIQUAC soit le modèle NRTL. Cependant, deux sets de paramètres ont été obtenus pour décrire d une part les équilibres liquide-liquide et d autre part, les enthalpies molaires d excès et les capacités calorifique spécifiques. Pour les systèmes {CO2 amine eau}, un modèle gamma-phi a été utilisé. Les paramètres d interaction ont été ajustés à partir de données d équilibre liquide vapeur et permettent de prédire les enthalpies de solutions, les limites de solubilités et la spéciation du système en fonction du taux de charge.The aim of this Ph.D. thesis is the thermodynamic study of {amine water} and {CO2 amine water} systems. The amines are demixing amines, which have the singularity to exhibit a liquid-liquid phase separation in aqueous solutions as a function of temperature, composition and CO2 loading charge. These compounds can be considerate as new absorbents for CO2 capture. The liquid-liquid phase separations for {amine water} systems were detected by calorimetry and visual techniques using a microcalorimeter (microDSCIII, Setaram) and an equilibrium cell (SPM20, Thar Technologies). In order to help in the thermodynamic representation of {amine water} systems, excess molar volumes, excess molar enthalpies and specific heat capacities were measured. The enthalpies of mixing were determined using a flow calorimetric technique. The calorimeter was a BT2.15 from Setaram equipped with a homemade mixing cell. Excess molar volumes were determined from densities measurement performed with a vibrating tube densitometer. The enthalpies of solution of CO2 with absorbent and limits of gas solubility were studied for selected systems of interest for CO2 capture using a flow calorimetric technique. Last part of this work concerns the development of thermodynamic models to correlate the experimental data. The Gibbs energies of studied {amine water} systems were calculating using both extended UNIQUAC and NRTL models. However, two sets of parameters were necessary to describe on one side the liquid-liquid equilibrium of mixtures and on the other side excess molar enthalpies and specific heat capacities. For {CO2 amine water} systems, a gamma-phi model was used. Interactions parameters were adjusted with vapor-liquid data and are able to predict the enthalpy of solution of CO2 in aqueous amine solutions, solubility limits of gas and speciation of the system as a function of loading charge.CLERMONT FD-Bib.électronique (631139902) / SudocSudocFranceF

Etude thermodynamique de la dissolution du dioxyde de carbone dans des solutions aqueuses d'alcanolamines

Cette thèse porte sur l'étude de l'enthalpie de dissolution du dioxyde de carbone dans des solutions aqueuses d'amine. Pour développer des modèles théoriques décrivant les systèmes (CO2-amine-eau) pour les conditions appliquées aux procédés industriels, il est nécessaire d'avoir des données expérimentales reliant la solubilité et l'enthalpie. Dans cette étude, nous avons utilisé une unité de mélange construite au laboratoire que nous avons adapté à un calorimètre SETARAM C-80 pour mesurer l'enthalpie de solution du CO2 dans cinq solutions aqueuses d'amine, (la 2-Amino-2-me thyl-1-propanol (AMP), la monoéthanolamine (MEA), la diéthanolamine (DEA), la triéthanolamine (TEA) et la méthyldiéthanolamine (MDEA) (15 et 30 mass%) à des températures comprises entre 322.5 K et 372.9 K et des pressions allant de 0.5 à 5 MPa. Les données de la littérature ont été utilisées pour ajuster deux modèles thermodynamiques d'équilibre de phases (un simple et un rigoureux). Le premier modèle résume l'absorption du CO2 par une seule réaction, tandis que le second prend en compte toutes les réactions à l'équilibre. Le modèle simple reproduit nos enthalpies expérimentales à plus ou moins 10%, tandis que le modèle rigoureux reproduit nos données avec un écart compris entre 5 et 20% selon l'amine considérée. Le calcul de l'enthalpie dans le modèle rigoureux est fortement dépendant des données de la littérature utilisées pour la réaction de protonation de l'amine. Ceci souligne la nécessité d'acquérir de nouvelles données expérimentales sur ces constantes d'équilibre pour améliorer le modèleCLERMONT FD-BCIU Sci.et Tech. (630142101) / SudocSudocFranceF

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

Etude densimétrique de systèmes ternaires en fonction de la temperature et de la composition

5 pages, confidentielEtude densimétrique de systèmes ternaires en fonction de la temperature et de la composition, sous forme de prestation de serviceLes mesures de densité des mélanges Oléate de méthyl – méthanol et Glycérol – méthanol ont été réalisées à 60, 130 et 200°C, pour une pression de 5 MPa. Ces mesures ont été réalisées pour 4 compositions pour le mélange Oléate de méthyl – méthanol et 9 compositions pour le mélange glycérol – methanol. La composition exacte des solutions est reportée dans le tableau I