The Experts below are selected from a list of 222 Experts worldwide ranked by ideXlab platform

Alan E Mather - One of the best experts on this subject based on the ideXlab platform.

M. Luísa P. Leitão - One of the best experts on this subject based on the ideXlab platform.

  • Enthalpy of Solution of terfenadine in ethanol/water mixtures
    Thermochimica Acta, 2000
    Co-Authors: João Canotilho, Felisbela S. Costa, Adriano Sousa, J. Simões Redinha, M. Luísa P. Leitão
    Abstract:

    Abstract The Enthalpy of Solution of terfenadine in ethanol/water mixtures, 0–20.5 wt.% of water was determined by calorimetry. A Sudden increase of 1–2 kJ mol −1 in the Enthalpy at a concentration value around 0.01 mol kg −1 is observed. This step in the Enthalpy is interpreted as due to solute n-mer aggregates formation. The solubility of terfenadine in the cosolvent systems used in the calorimetric studies was determined.

  • Enthalpy of Solution of Terfenadine in Different Solvents
    Journal of Thermal Analysis and Calorimetry, 1999
    Co-Authors: João Canotilho, Felisbela S. Costa, Adriano Sousa, J. Simões Redinha, M. Luísa P. Leitão
    Abstract:

    Enthalpies of Solution of various terfenadine samples in methanol and in ethanol were measured. Samples were prepared by crystallization in different solvents. The calorimetric results give important information on crystal structure of the terfenadine forms and on the solute/solvent interactions of this compound with the solvents.

Kenneth N. Marsh - One of the best experts on this subject based on the ideXlab platform.

James K. Carson - One of the best experts on this subject based on the ideXlab platform.

Jean Yves Coxam - One of the best experts on this subject based on the ideXlab platform.

  • Experimental determination and modeling of Enthalpy of Solution of carbon dioxide in aqueous Solutions of demixing amines
    2014
    Co-Authors: Yohann Coulier, Karine Ballerat-busserolles, Javier Mesones Mora, Alexander Lowe, Jean Yves Coxam
    Abstract:

    Carbon Capture and Storage (CCS) is a solid option for CO2 mitigation in the atmosphere. Post-combustion capture processes using chemical solvents are considered as one of the most adequate method for CCS [1]. However, these processes are energy intensive and need to be improved in order to develop an economically viable method to separate CO2 from industrial effluent. For this purpose the DMXTM process [2] using aqueous Solutions of demixing amines has been developed by IFP Energies nouvelles over the past few years. The novelty of this solvent is to undergo a liquid-liquid phase separation at a specific temperature and CO2 concentration. Such a phase separation will concentrate CO2 into the water rich phase. Then only this part of the solvent will be heated in the regeneration step of the separation process. The DACOOTA project, supported simultaneously by the French National Agency of Research (ANR) and the Natural Sciences and Engineering Research Council of Canada (NSERC), concerns the understanding of this class of amines for CCS. In this work, the absorption of CO2 in aqueous Solutions of 2-methylpiperidine, 3-methylpiperidine and 4-methylpiperidine, has been studied at different temperatures, pressures and amine compositions. These three cyclic amines undergo a Lower Critical Solution (LCST) in aqueous Solution [3,4]. The heats of mixing of CO2 in aqueous Solutions of amine have been measured by a flow calorimetric technique [5]. The technique makes it possible simultaneous determination of the enthalpies of Solution and solubility limits. The experimental enthalpies of Solution of CO2 for these three systems {x-methylpiperidine – water – CO2} are compared with data derived from a rigorous thermodynamic model of phase equilibria based on a γ-ϕ approach [6, 7]. Interaction parameters were chosen to be adjustable parameters in this model and were fitted to vapor-liquid equilibrium data. In order to improve the understanding of this class of amine, the influence of the position of the methyl group on the Enthalpy of Solution of CO2 will be discussed.

  • Thermodynamics of CO2 absorption in aqueous ethanolamine Solutions: experimental study of the Enthalpy of Solution by flow calorimetry
    2012
    Co-Authors: Jean Yves Coxam, Hugues Arcis, Karine Ballerat-busserolles, Laurence Rodier
    Abstract:

    The capture of carbon dioxide from post combustion emission is one of the challenges for reducing the release of greenhouse gases into the atmosphere, and, aqueous amine Solutions are known to be efficient chemical solvents for this purpose. Energetic effects involved in such processes are of large interest for the industry as the energy cost for CO2 removal is directly related to the Enthalpy of Solution of CO2 into the absorbing fluid. This paper reports measurement of Enthalpy of Solution of CO2 into aqueous Solutions of ethanolamines (w = 0.1500 and 0.300) at temperatures of 323 K and 373 K, and for pressures from 0.2 to 5 MPa for different loading (mol CO2 / mol amine). Experiments were conducted at constant temperature and pressure, using a custom-made flow-mixing unit in the SETARAM C-80 calorimeter. Three different amines were selected (monoethanolamine (MEA), diethanolamine (DEA) and triethanolamine (TEA)). A thermodynamic model considering all reactions taking place, and, adjusted only on vapour-liquid-equilibrium properties, was used to model the Enthalpy of Solution of CO2 in the different absorbent. In the case of DEA, different literature equilibrium constant correlations for the amine protonation and the carbamate formation were tested. The energetic contributions from each chemical reaction involved during the capture process are discussed. The reaction of amine protonation was found to provide the most important energetic contribution just after the carbamate formation when that reaction was possible. In the case of DEA, the Enthalpy calculation was strongly dependent on the choice of the correlation used for the equilibrium constants. Accurate protonation constant measurements are needed to resolve this issue, so that the calorimetric data can be used as the basis of a comprehensive model that covers a wide range of temperature and pressure.

  • Measurement and Modeling of Enthalpy of Solution of Carbon Dioxide in Aqueous Solutions of Diethanolamine at Temperatures of (322.5 and 372.9) K and Pressures up to 3 MPa
    Journal of Chemical and Engineering Data, 2012
    Co-Authors: Hugues Arcis, Karine Ballerat-busserolles, Laurence Rodier, Jean Yves Coxam
    Abstract:

    The enthalpies of Solution (ΔsolH) of carbon dioxide (CO2) in two aqueous Solutions (w = 0.1500 and w = 0.3000) of diethanolamine (DEA) have been measured at two temperatures ((322.5 and 372.9) K) and pressures up to 3 MPa. Measurements were carried out by a flow calorimetric technique using a custom-made flow-mixing unit combined with a SETARAM C-80 isothermal differential heat-flux calorimeter. Enthalpies of Solution of CO2 (ΔsolH) have been obtained as function of loading, α (moles CO2/mol amine). Influences of temperature, pressure, and absorbent composition have been discussed. Solubility data of the gas into the different absorbent (s) were derived from the enthalpic data. The experimental enthalpies of Solution (ΔsolH) of carbon dioxide (CO2) in the two aqueous Solutions of diethanolamine have been compared with data derived from a rigorous thermodynamic model of phase equilibria based on a γ- approach. Interaction parameters were chosen to be adjustable parameters in this model and were fitted to vapor-liquid equilibrium data. Several formulations for the amine protonation and carbamate formation equilibrium constants have been tested. The different contributions to the Enthalpy of Solution of CO2 in aqueous Solutions of DEA have been analyzed.

  • Interest of calorimetry to study carbon dioxide disSolution in aqueous Solutions of amines
    2011
    Co-Authors: Karine Ballerat-busserolles, Laurence Rodier, Yohann Coulier, Mickaël R. Simond, Jean Yves Coxam
    Abstract:

    The reduction of emissions of greenhouse gases is an option to fight against the global warning phenomenon. It concerns mainly the anthropogenic emissions of carbon dioxide CO2, resulting from fossil fuels combustion. This can be realized by CO2 capture in industrial effluents with a process, initially developed to remove acid gases from natural gas, consisting in CO2 separation by disSolution in aqueous Solution of amine. The reaction of disSolution is reversible but the solvent regeneration represents actually an important economic cost in the treatment of post combustion effluents (1). The energy required for desorption of CO2 is related to the Enthalpy of CO2 disSolution. The development of thermodynamic models to represent the gas-liquid equilibrium is then of interest in designing CO2 capture process. However the system {CO2 - H2O - Amine} is complex, because of the chemical reactions involved in gas disSolution. It has been particularly shown (2,3) that the development of rigorous model supposed to precisely know the equilibrium constant of the different chemical reactions. This work presents the interest of direct measurement of Enthalpy of Solution of carbon dioxide in aqueous Solutions of amines. The Enthalpy of Solution can be derived from thermodynamic model. The Enthalpy appears as a combination of different contribution terms related to the physical disSolution and the chemical reactions. Different amines(4-5) were investigated and experimental Enthalpy data were used to test the ability of the model to predict Enthalpy of Solution. It appears that a good agreement between experimental and calculated enthalpies mainly depends on the precision on the contribution term attributed to the protonation of the amine. In case of primary and secondary amines, the results show difficulties to take into account the carbamate formation for which equilibrium constant is rarely available in literature. Then in addition to direct measurement of Enthalpy of Solution the calorimetric technique can also be used to study separately different contribution terms. References [1] Lecomte, F., Broutin, P., Lebas, E.: CO2 capture, Technologies to reduce greenhouse gas emissions. TECHNIP ed., Paris (2010) [2] Arcis, H., Rodier, L., Ballerat-Busserolles, K., Coxam, J.-Y. J. Chem. Thermodynamics. 41, 783-789 (2009) [3] Kim, I., Hoff, K.A., Hessen, E.T., Haug-Warberg, T., Svendsen, H.F. Chem. Eng. Sci. 64, 2027-2038 (2009) [4] H. Arcis, L. Rodier, K. Ballerat-Busserolles, J-Y Coxam, J. Chem. Thermodyn.,(2008) 40, 1022-1029. [5] Arcis, H., Rodier, L., Ballerat-Busserolles, K., Coxam, J.-Y. J. Chem. Thermodynamics. 41, 836-841 (2009)

  • Modeling of Enthalpy of Solution of Carbon Dioxyde in Aqueous Solution of Amine
    2009
    Co-Authors: Jean Yves Coxam, Karine Ballerat-busserolles, Laurence Rodier, Hugues Arcis
    Abstract:

    The {CO2-H2O-amine} systems are of interest in order to develop carbon dioxide (CO2) capture processes. Because of environmental impact, particularly for global warming effect, CO2 emissions have to be limited. One option is to remove CO2 from post combustion effluent in industries such as cement, metallurgy or power plants. The most common processes are based on cycles of gas absorption in amine Solution and regeneration of the Solution in a stripper. The economical cost of the second step must be reduced in order to develop the CO2 treatment in the industry. The regeneration is performed by heating the Solution. The required energy for gas desorption is directly related to the Enthalpy of Solution of CO2 in the amine Solution. Direct measurements of Enthalpy of Solution are not easy to carry out and experimental data are relatively scarce compared to vapor-liquid equilibrium (VLE) data. The objective of this work is to analyze how Enthalpy of Solution can be calculated from available VLE data. The mechanism of gas absorption is a combination of chemical reactions and physical absorption that can be described by thermodynamic models (1-3). The chemical and physical equilibria are represented using chemical equilibium constants and Henry's constants obtained from literature. The none-idealities in the liquid and gas phases are taken into account using a g-f approach. In a first step, the interaction parameters, used in the model for the calculation of activity coefficients4, are adjusted to correlate the VLE data. Then, the enthalpies of Solution are derived5 from the equilibrium equations using thermodynamic relationship. The calculated values are compared with experimental data (6-7). The total Enthalpy of Solution is divided in several contributions related to amine protonation, CO2 and water dissociation and gas-liquid equilibria. These Enthalpy contributions are obtained, among others, from the temperature derivations of the related equilibrium constants. When different temperature correlations are available in the literature for the same constant, the influence on the calculated Enthalpy is analyzed.