Christelle Miqueu | Université De Pau Et Des Pays De L'adour (original) (raw)
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Papers by Christelle Miqueu
HAL (Le Centre pour la Communication Scientifique Directe), 2012
The Journal of Chemical Physics, 2009
In a first part, interfacial properties of a pure monoatomic fluid interacting through the Mie n ... more In a first part, interfacial properties of a pure monoatomic fluid interacting through the Mie n −6 potential ͑n = 8, 10, 12, and 20͒ have been studied using extensive molecular simulations. Monte Carlo and molecular dynamics simulations have been employed, using, respectively, the test area approach and the mechanic route. In order to yield reference values, simulations have been performed with a cutoff radius equal to 10, which is shown to be sufficient to avoid long range corrections. It is shown that both approaches provide results consistent with each other. Using the molecular simulations results, it is demonstrated that a unique scaling law is able to provide an accurate estimation of the surface tension whatever the repulsive exponent n, even far from the critical point. Furthermore, it is shown that the surface tension of the Mie n − 6 fluid is as well accurately described by a unique Parachor's law. Density profiles are shown to be well represented by the tanh mean field profile, with slight deviations for the lowest temperatures and the smallest n. In addition, the interfacial width is shown to increase when n decreases ͑for a given reduced temperature͒ and to follow the usual scaling behavior for not too low temperature. In a second part, interfacial properties of the Mie n − 6 fluid computed by the gradient theory, coupled with an equation of state based on the Barker-Henderson perturbation theory, have been compared with those obtained by molecular simulations. It is demonstrated that, even far from the critical point, the gradient theory is efficient to compute surface tensions and density profiles of this model fluid, provided the equation of state accurately model the phase behavior of the fluid involved ͑which is not the case for n = 8 in this study͒.
The gradient theory of inhomogeneous fluid is for the first time used to study the fluid-fluid in... more The gradient theory of inhomogeneous fluid is for the first time used to study the fluid-fluid interfaces of real petroleum mixtures (gas condensate and oils) at reservoir conditions. The theory is combined with the volume-corrected Peng-Robinson equation of state which allows a good description of the vapour-liquid equilibria of these mixtures. First, it is demonstrated that a correlation that was derived previously to compute the influence parameters of pure hydrocarbons can be also used to obtain the influence parameters of cuts and pseudocompounds present in the petroleum fluids. It turns out that the gradient theory allows estimates of the surface tension in excellent agreement with the experimental data. In any case, it is found to be much more superior to the traditional parachor method that systematically underestimates the surface tension of these mixtures. Furthermore, unlike the parachor method, the gradient theory proves to be nearly insensitive to the compositional description of the fluid provided that the number of pseudocompounds is not too small (N > 5).
Poromechanics offers a consistent theoretical framework for describing the mechanical response of... more Poromechanics offers a consistent theoretical framework for describing the mechanical response of porous solids fully or partially saturated with a fluid phase. When dealing with fully saturated microporous materials, which exhibit pores of the nanometer size, aside from the fluid pressure acting on the pore walls additional effects due to adsorption and confinement of the fluid molecules in the smallest pores must be accounted for. From the mechanical point of view, these phenomena result into volumetric deformations of the porous solid: the so-called "swelling" phenomenon. The present work investigates how the poromechanical theory should be refined in order to describe adsorption and confinement induced swelling in microporous solids. Firstly, we report molecular simulation results that show that the pressure and density of the fluid in the smallest pores are responsible for the volumetric deformation of the material. Secondly, poromechanics is revisited in the context of a microporous material with a continuous pore size distribution. Accounting for the thermodynamic equilibrium of the fluid phase in the overall pore space, the new formulation introduces an apparent porosity and an interaction free energy. We use a prototype constitutive relation relating these two quantities to the Gibbs adsorption isotherm, and then 1 Corresponding calculate the induced deformation of the solid matrix. Agreement with experimental data found in the literature is observed. As an illustrating example, we show the predicted strains in the case of adsorption of methane on activated carbon.
The Journal of Physical Chemistry C, 2014
Application of a renormalization-group treatment to the statistical associating fluid theory for ... more Application of a renormalization-group treatment to the statistical associating fluid theory for potentials of variable range (SAFT-VR) Development of an equation of state for electrolyte solutions by combining the statistical associating fluid theory and the mean spherical approximation for the nonprimitive model As a first step of an ongoing study of thermodynamic properties and adsorption of complex fluids in confined media, we present a new theoretical description for spherical monomers using the Statistical Associating Fluid Theory for potential of Variable Range (SAFT-VR) and a Non-Local Density Functional Theory (NLDFT) with Weighted Density Approximations (WDA). The well-known Modified Fundamental Measure Theory is used to describe the inhomogeneous hard-sphere contribution as a reference for the monomer and two WDA approaches are developed for the dispersive terms from the high-temperature Barker and Henderson perturbation expansion. The first approach extends the dispersive contributions using the scalar and vector weighted densities introduced in the Fundamental Measure Theory (FMT) and the second one uses a coarse-grained (CG) approach with a unique weighted density. To test the accuracy of this new NLDFT/SAFT-VR coupling, the two versions of the theoretical model are compared with Grand Canonical Monte Carlo (GCMC) molecular simulations using the same molecular model. Only the version with the "CG" approach for the dispersive terms provides results in excellent agreement with GCMC calculations in a wide range of conditions while the "FMT" extension version gives a good representation solely at low pressures. Hence, the "CG" version of the theoretical model is used to reproduce methane adsorption isotherms in a Carbon Molecular Sieve and compared with experimental data after a characterization of the material. The whole results show an excellent agreement between modeling and experiments. Thus, through a complete and consistent comparison both with molecular simulations and with experimental data, the NLDFT/SAFT-VR theory has been validated for the description of monomers.
Journal of Chemical & Engineering Data, 2009
In this work, we have measured the densities of binary mixtures of n-dodecane, 1-phenyl-2-methylp... more In this work, we have measured the densities of binary mixtures of n-dodecane, 1-phenyl-2-methylpropane, and 1,2,3,4-tetrahydronaphthalene for pressures varying from (0.1 to 20) MPa at an average temperature of 25°C. By a derivative method, we have determined the thermal expansion and concentration expansion coefficients for binary mixtures of equal mass fraction. In addition, viscosities have been measured and compared with theoretical estimates. To accurately predict the thermal expansion and concentration expansion coefficients, the densities of the binary mixtures were calculated using PC-SAFT, Peng-Robinson, and volume translated Peng-Robinson equations of state. The comparison with measured densities showed that PC-SAFT has a better agreement with experimental data than the other equations of state. From calculated densities we evaluated the thermal expansion and concentration expansion variation coefficients. We have found that PC-SAFT gives a suitable prediction for the two derivative properties unlike the two other equations of state. The combination of the model of Lohrenz-Bray-Clark for the viscosity of liquid mixtures and the densities calculated with the three equations of state gave a poor prediction of the viscosities of the binary mixtures. † Part of the special section "2008 European Conference on Thermophysical Properties".
Fluid Phase Equilibria, 2005
With the final purpose of describing the important aqueous + hydrocarbon liquid-liquid interfaces... more With the final purpose of describing the important aqueous + hydrocarbon liquid-liquid interfaces, the gradient theory was combined with the Cubic-Plus-Association equation of state (CPA EOS), taking advantage of the correct representation of interfacial tensions provided by the gradient theory and the correct phase equilibrium of water + hydrocarbon systems already obtained from CPA.
![Research paper thumbnail of Corrigendum to “Modelling of the surface tension of pure components with the gradient theory of fluid interfaces: a simple and accurate expression for the influence parameters”: [Fluid Phase Equilibria 207 (2003) 225–246]](https://attachments.academia-assets.com/45672097/thumbnails/1.jpg)
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Adsorption, 2014
The adsorption of pure methane in activated carbon Ecosorb was studied by combining grand canonic... more The adsorption of pure methane in activated carbon Ecosorb was studied by combining grand canonical ensemble Monte Carlo molecular simulations and an experimental approach based on a gravimetric device. Experimental and calculated adsorption isotherms of methane were determined in supercritical conditions at 303.15 and 353.15 K and pressures up to 10 MPa. The comparison between both experimental and estimated data proves the consistency of the methodology used in this work, starting from the characterization of the porous media in terms of pore size distribution, the determination of the experimental adsorption isotherms, and the final estimation of computational results through estimated isotherms determination. Moreover, additional differential enthalpy of adsorption calculations were compared with experimental values obtained by means of a manometric/ calorimetric technique. The good agreement shows the strength and the originality of this paper by combining experimental and computational homemade results allowing a complete characterization of the activated carbon substrate and its methane storage capacity.
The Journal of Chemical Physics, 2014
Application of a renormalization-group treatment to the statistical associating fluid theory for ... more Application of a renormalization-group treatment to the statistical associating fluid theory for potentials of variable range (SAFT-VR) Development of an equation of state for electrolyte solutions by combining the statistical associating fluid theory and the mean spherical approximation for the nonprimitive model As a first step of an ongoing study of thermodynamic properties and adsorption of complex fluids in confined media, we present a new theoretical description for spherical monomers using the Statistical Associating Fluid Theory for potential of Variable Range (SAFT-VR) and a Non-Local Density Functional Theory (NLDFT) with Weighted Density Approximations (WDA). The well-known Modified Fundamental Measure Theory is used to describe the inhomogeneous hard-sphere contribution as a reference for the monomer and two WDA approaches are developed for the dispersive terms from the high-temperature Barker and Henderson perturbation expansion. The first approach extends the dispersive contributions using the scalar and vector weighted densities introduced in the Fundamental Measure Theory (FMT) and the second one uses a coarse-grained (CG) approach with a unique weighted density. To test the accuracy of this new NLDFT/SAFT-VR coupling, the two versions of the theoretical model are compared with Grand Canonical Monte Carlo (GCMC) molecular simulations using the same molecular model. Only the version with the "CG" approach for the dispersive terms provides results in excellent agreement with GCMC calculations in a wide range of conditions while the "FMT" extension version gives a good representation solely at low pressures. Hence, the "CG" version of the theoretical model is used to reproduce methane adsorption isotherms in a Carbon Molecular Sieve and compared with experimental data after a characterization of the material. The whole results show an excellent agreement between modeling and experiments. Thus, through a complete and consistent comparison both with molecular simulations and with experimental data, the NLDFT/SAFT-VR theory has been validated for the description of monomers.
HAL (Le Centre pour la Communication Scientifique Directe), 2012
The Journal of Chemical Physics, 2009
In a first part, interfacial properties of a pure monoatomic fluid interacting through the Mie n ... more In a first part, interfacial properties of a pure monoatomic fluid interacting through the Mie n −6 potential ͑n = 8, 10, 12, and 20͒ have been studied using extensive molecular simulations. Monte Carlo and molecular dynamics simulations have been employed, using, respectively, the test area approach and the mechanic route. In order to yield reference values, simulations have been performed with a cutoff radius equal to 10, which is shown to be sufficient to avoid long range corrections. It is shown that both approaches provide results consistent with each other. Using the molecular simulations results, it is demonstrated that a unique scaling law is able to provide an accurate estimation of the surface tension whatever the repulsive exponent n, even far from the critical point. Furthermore, it is shown that the surface tension of the Mie n − 6 fluid is as well accurately described by a unique Parachor's law. Density profiles are shown to be well represented by the tanh mean field profile, with slight deviations for the lowest temperatures and the smallest n. In addition, the interfacial width is shown to increase when n decreases ͑for a given reduced temperature͒ and to follow the usual scaling behavior for not too low temperature. In a second part, interfacial properties of the Mie n − 6 fluid computed by the gradient theory, coupled with an equation of state based on the Barker-Henderson perturbation theory, have been compared with those obtained by molecular simulations. It is demonstrated that, even far from the critical point, the gradient theory is efficient to compute surface tensions and density profiles of this model fluid, provided the equation of state accurately model the phase behavior of the fluid involved ͑which is not the case for n = 8 in this study͒.
The gradient theory of inhomogeneous fluid is for the first time used to study the fluid-fluid in... more The gradient theory of inhomogeneous fluid is for the first time used to study the fluid-fluid interfaces of real petroleum mixtures (gas condensate and oils) at reservoir conditions. The theory is combined with the volume-corrected Peng-Robinson equation of state which allows a good description of the vapour-liquid equilibria of these mixtures. First, it is demonstrated that a correlation that was derived previously to compute the influence parameters of pure hydrocarbons can be also used to obtain the influence parameters of cuts and pseudocompounds present in the petroleum fluids. It turns out that the gradient theory allows estimates of the surface tension in excellent agreement with the experimental data. In any case, it is found to be much more superior to the traditional parachor method that systematically underestimates the surface tension of these mixtures. Furthermore, unlike the parachor method, the gradient theory proves to be nearly insensitive to the compositional description of the fluid provided that the number of pseudocompounds is not too small (N > 5).
Poromechanics offers a consistent theoretical framework for describing the mechanical response of... more Poromechanics offers a consistent theoretical framework for describing the mechanical response of porous solids fully or partially saturated with a fluid phase. When dealing with fully saturated microporous materials, which exhibit pores of the nanometer size, aside from the fluid pressure acting on the pore walls additional effects due to adsorption and confinement of the fluid molecules in the smallest pores must be accounted for. From the mechanical point of view, these phenomena result into volumetric deformations of the porous solid: the so-called "swelling" phenomenon. The present work investigates how the poromechanical theory should be refined in order to describe adsorption and confinement induced swelling in microporous solids. Firstly, we report molecular simulation results that show that the pressure and density of the fluid in the smallest pores are responsible for the volumetric deformation of the material. Secondly, poromechanics is revisited in the context of a microporous material with a continuous pore size distribution. Accounting for the thermodynamic equilibrium of the fluid phase in the overall pore space, the new formulation introduces an apparent porosity and an interaction free energy. We use a prototype constitutive relation relating these two quantities to the Gibbs adsorption isotherm, and then 1 Corresponding calculate the induced deformation of the solid matrix. Agreement with experimental data found in the literature is observed. As an illustrating example, we show the predicted strains in the case of adsorption of methane on activated carbon.
The Journal of Physical Chemistry C, 2014
Application of a renormalization-group treatment to the statistical associating fluid theory for ... more Application of a renormalization-group treatment to the statistical associating fluid theory for potentials of variable range (SAFT-VR) Development of an equation of state for electrolyte solutions by combining the statistical associating fluid theory and the mean spherical approximation for the nonprimitive model As a first step of an ongoing study of thermodynamic properties and adsorption of complex fluids in confined media, we present a new theoretical description for spherical monomers using the Statistical Associating Fluid Theory for potential of Variable Range (SAFT-VR) and a Non-Local Density Functional Theory (NLDFT) with Weighted Density Approximations (WDA). The well-known Modified Fundamental Measure Theory is used to describe the inhomogeneous hard-sphere contribution as a reference for the monomer and two WDA approaches are developed for the dispersive terms from the high-temperature Barker and Henderson perturbation expansion. The first approach extends the dispersive contributions using the scalar and vector weighted densities introduced in the Fundamental Measure Theory (FMT) and the second one uses a coarse-grained (CG) approach with a unique weighted density. To test the accuracy of this new NLDFT/SAFT-VR coupling, the two versions of the theoretical model are compared with Grand Canonical Monte Carlo (GCMC) molecular simulations using the same molecular model. Only the version with the "CG" approach for the dispersive terms provides results in excellent agreement with GCMC calculations in a wide range of conditions while the "FMT" extension version gives a good representation solely at low pressures. Hence, the "CG" version of the theoretical model is used to reproduce methane adsorption isotherms in a Carbon Molecular Sieve and compared with experimental data after a characterization of the material. The whole results show an excellent agreement between modeling and experiments. Thus, through a complete and consistent comparison both with molecular simulations and with experimental data, the NLDFT/SAFT-VR theory has been validated for the description of monomers.
Journal of Chemical & Engineering Data, 2009
In this work, we have measured the densities of binary mixtures of n-dodecane, 1-phenyl-2-methylp... more In this work, we have measured the densities of binary mixtures of n-dodecane, 1-phenyl-2-methylpropane, and 1,2,3,4-tetrahydronaphthalene for pressures varying from (0.1 to 20) MPa at an average temperature of 25°C. By a derivative method, we have determined the thermal expansion and concentration expansion coefficients for binary mixtures of equal mass fraction. In addition, viscosities have been measured and compared with theoretical estimates. To accurately predict the thermal expansion and concentration expansion coefficients, the densities of the binary mixtures were calculated using PC-SAFT, Peng-Robinson, and volume translated Peng-Robinson equations of state. The comparison with measured densities showed that PC-SAFT has a better agreement with experimental data than the other equations of state. From calculated densities we evaluated the thermal expansion and concentration expansion variation coefficients. We have found that PC-SAFT gives a suitable prediction for the two derivative properties unlike the two other equations of state. The combination of the model of Lohrenz-Bray-Clark for the viscosity of liquid mixtures and the densities calculated with the three equations of state gave a poor prediction of the viscosities of the binary mixtures. † Part of the special section "2008 European Conference on Thermophysical Properties".
Fluid Phase Equilibria, 2005
With the final purpose of describing the important aqueous + hydrocarbon liquid-liquid interfaces... more With the final purpose of describing the important aqueous + hydrocarbon liquid-liquid interfaces, the gradient theory was combined with the Cubic-Plus-Association equation of state (CPA EOS), taking advantage of the correct representation of interfacial tensions provided by the gradient theory and the correct phase equilibrium of water + hydrocarbon systems already obtained from CPA.
Adsorption, 2014
The adsorption of pure methane in activated carbon Ecosorb was studied by combining grand canonic... more The adsorption of pure methane in activated carbon Ecosorb was studied by combining grand canonical ensemble Monte Carlo molecular simulations and an experimental approach based on a gravimetric device. Experimental and calculated adsorption isotherms of methane were determined in supercritical conditions at 303.15 and 353.15 K and pressures up to 10 MPa. The comparison between both experimental and estimated data proves the consistency of the methodology used in this work, starting from the characterization of the porous media in terms of pore size distribution, the determination of the experimental adsorption isotherms, and the final estimation of computational results through estimated isotherms determination. Moreover, additional differential enthalpy of adsorption calculations were compared with experimental values obtained by means of a manometric/ calorimetric technique. The good agreement shows the strength and the originality of this paper by combining experimental and computational homemade results allowing a complete characterization of the activated carbon substrate and its methane storage capacity.
The Journal of Chemical Physics, 2014
Application of a renormalization-group treatment to the statistical associating fluid theory for ... more Application of a renormalization-group treatment to the statistical associating fluid theory for potentials of variable range (SAFT-VR) Development of an equation of state for electrolyte solutions by combining the statistical associating fluid theory and the mean spherical approximation for the nonprimitive model As a first step of an ongoing study of thermodynamic properties and adsorption of complex fluids in confined media, we present a new theoretical description for spherical monomers using the Statistical Associating Fluid Theory for potential of Variable Range (SAFT-VR) and a Non-Local Density Functional Theory (NLDFT) with Weighted Density Approximations (WDA). The well-known Modified Fundamental Measure Theory is used to describe the inhomogeneous hard-sphere contribution as a reference for the monomer and two WDA approaches are developed for the dispersive terms from the high-temperature Barker and Henderson perturbation expansion. The first approach extends the dispersive contributions using the scalar and vector weighted densities introduced in the Fundamental Measure Theory (FMT) and the second one uses a coarse-grained (CG) approach with a unique weighted density. To test the accuracy of this new NLDFT/SAFT-VR coupling, the two versions of the theoretical model are compared with Grand Canonical Monte Carlo (GCMC) molecular simulations using the same molecular model. Only the version with the "CG" approach for the dispersive terms provides results in excellent agreement with GCMC calculations in a wide range of conditions while the "FMT" extension version gives a good representation solely at low pressures. Hence, the "CG" version of the theoretical model is used to reproduce methane adsorption isotherms in a Carbon Molecular Sieve and compared with experimental data after a characterization of the material. The whole results show an excellent agreement between modeling and experiments. Thus, through a complete and consistent comparison both with molecular simulations and with experimental data, the NLDFT/SAFT-VR theory has been validated for the description of monomers.