Equation of State for the Phase Behavior of Carbon Dioxide−Polymer Systems / Hun Yong Shin in Industrial & engineering chemistry research, Vol. 49 N° 16 (Août 2010)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 49 N° 16 (Août 2010) . - pp. 7678–7684 Titre : Equation of State for the Phase Behavior of Carbon Dioxide−Polymer Systems Type de document : texte imprimé Auteurs : Hun Yong Shin, Auteur ; Jianzhong Wu, Auteur Année de publication : 2010 Article en page(s) : pp. 7678–7684 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Thermodynamic Multicomponent Solutions Résumé : We proposed a hybrid equation of state for CO2−polymer systems that utilizes the Peng−Robinson (PR) equation of state for the molecular excluded-volume effects and the van der Waals attractions, and equations from the statistical associating fluid theory (SAFT) for the polymer intrachain correlations and for the short-ranged forces due to weakly polar or association interactions. The numerical performance of the new equation of state was tested by its application to correlating the PVT behavior of pure CO2, including both the vapor−liquid coexistence densities, the vapor pressure, and the specific density of condensed CO2 at near-critical and supercritical conditions, and to the volumetric properties of high molecular weight alkanes and a few representative polymers. With the parameters from the original PR equation of state for nonpolar monomeric fluids and additional ones to account for the solvent polarity and the solute degree of polymerization, the new equation of state was successfully used to calculate the phase behavior of CO2−polymer systems, including the vapor−liquid equilibria of ternary systems. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100903f [article] Equation of State for the Phase Behavior of Carbon Dioxide−Polymer Systems [texte imprimé] / Hun Yong Shin, Auteur ; Jianzhong Wu, Auteur . - 2010 . - pp. 7678–7684. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 16 (Août 2010) . - pp. 7678–7684 Mots-clés : Thermodynamic Multicomponent Solutions Résumé : We proposed a hybrid equation of state for CO2−polymer systems that utilizes the Peng−Robinson (PR) equation of state for the molecular excluded-volume effects and the van der Waals attractions, and equations from the statistical associating fluid theory (SAFT) for the polymer intrachain correlations and for the short-ranged forces due to weakly polar or association interactions. The numerical performance of the new equation of state was tested by its application to correlating the PVT behavior of pure CO2, including both the vapor−liquid coexistence densities, the vapor pressure, and the specific density of condensed CO2 at near-critical and supercritical conditions, and to the volumetric properties of high molecular weight alkanes and a few representative polymers. With the parameters from the original PR equation of state for nonpolar monomeric fluids and additional ones to account for the solvent polarity and the solute degree of polymerization, the new equation of state was successfully used to calculate the phase behavior of CO2−polymer systems, including the vapor−liquid equilibria of ternary systems. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100903f

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Toward a quantitative theory of ultrasmall liquid droplets and vapor / Zhidong Li in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 4988–4995 Titre : Toward a quantitative theory of ultrasmall liquid droplets and vapor : liquid nucleation Type de document : texte imprimé Auteurs : Zhidong Li, Auteur ; Jianzhong Wu, Auteur Année de publication : 2008 Article en page(s) : p. 4988–4995 Note générale : Bibliogr. p. 4994-4995 Langues : Anglais (eng) Mots-clés : Small systems -- thermodynamic properties Nonmean-field density Ultrasmall liquid dropletsLennard-Jones model Résumé : Thermodynamic properties of small systems can be drastically different from those corresponding to their macroscopic counterparts due to the surface and fluctuation effects. While the equations of state for macroscopic systems are well advanced, quantitative predictions of the structural and thermodynamic properties of small systems from a molecular perspective remain a daunting challenge. This article illustrates applications of a nonmean-field density functional theory to two types of ultrasmall liquid droplets: one is stabilized in a container of finite size and the other is unstable as appeared during vapor—liquid nucleation. For small systems of simple fluids represented by the Lennard-Jones model, theoretical predictions are compared with results from molecular simulations for the microscopic structure, the droplet size, and the free energy of formation over a broad range of conditions. The numerical agreement of theory with simulation data is comparable to that for the corresponding macroscopic systems. While the Tolman length, a correlation of curvature on surface tension, is negligible at least for small droplets of simple fluids, the vapor—liquid interfacial tension declines with the droplet size approximately proportional to the Gaussian curvature. Surprisingly, the Laplace equation for pressure change across a curved surface remains accurate even for a liquid droplet with the radius only a few times the molecular diameter. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie070578i [article] Toward a quantitative theory of ultrasmall liquid droplets and vapor : liquid nucleation [texte imprimé] / Zhidong Li, Auteur ; Jianzhong Wu, Auteur . - 2008 . - p. 4988–4995. Bibliogr. p. 4994-4995 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 4988–4995 Mots-clés : Small systems -- thermodynamic properties Nonmean-field density Ultrasmall liquid dropletsLennard-Jones model Résumé : Thermodynamic properties of small systems can be drastically different from those corresponding to their macroscopic counterparts due to the surface and fluctuation effects. While the equations of state for macroscopic systems are well advanced, quantitative predictions of the structural and thermodynamic properties of small systems from a molecular perspective remain a daunting challenge. This article illustrates applications of a nonmean-field density functional theory to two types of ultrasmall liquid droplets: one is stabilized in a container of finite size and the other is unstable as appeared during vapor—liquid nucleation. For small systems of simple fluids represented by the Lennard-Jones model, theoretical predictions are compared with results from molecular simulations for the microscopic structure, the droplet size, and the free energy of formation over a broad range of conditions. The numerical agreement of theory with simulation data is comparable to that for the corresponding macroscopic systems. While the Tolman length, a correlation of curvature on surface tension, is negligible at least for small droplets of simple fluids, the vapor—liquid interfacial tension declines with the droplet size approximately proportional to the Gaussian curvature. Surprisingly, the Laplace equation for pressure change across a curved surface remains accurate even for a liquid droplet with the radius only a few times the molecular diameter. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie070578i

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