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Automated generation of phase diagrams for binary systems with azeotropic behavior / Martín Cismondi in Industrial & engineering chemistry research, Vol. 47 N° 23 (Décembre 2008) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 47 N° 23 (Décembre 2008) . - p. 9728–9743 Titre : Automated generation of phase diagrams for binary systems with azeotropic behavior Type de document : texte imprimé Auteurs : Martín Cismondi, Auteur ; Michael L. Michelsen, Auteur ; Marcelo S. Zabaloy, Auteur Année de publication : 2009 Article en page(s) : p. 9728–9743 Note générale : Chemistry engineering Langues : Anglais (eng) Mots-clés : Automated  generation  Diagrams  Azeotropic  behavior Résumé : In this work, we propose a computational strategy and methods for the automated calculation of complete loci of homogeneous azeotropy of binary mixtures and the related Pxy and Txy diagrams for models of the equation-of-state (EOS) type. The strategy consists of first finding the system’s azeotropic end points (AEPs). These can exist on vapor−liquid (VL) critical lines (CAEPs), on liquid−liquid−vapor (LLV) lines (HAEPs), and on pure-compound vapor pressure lines (PAEPs). Next, for the chosen binary system, we generate one or two azeotropic lines. Each of these lines has, as its starting point, one of the previously identified AEPs. We calculate the azeotropic lines using a numerical continuation method that solves the nonlinear azeotropic system of equations under a range of conditions and efficiently tracks entire azeotropic curves. We have integrated our strategy for calculating azeotropic lines into a general algorithm for the single-run computation of binary global phase equilibrium diagrams (GPEDs). GPEDs are defined by pure-compound, critical, LLV, and azeotropic lines. We implemented this general algorithm in the computer program GPEC (Global Phase Equilibrium Calculations), which makes it possible to evaluate, at a glance, the behavior of a given model−parameter values combination, for a chosen model and binary system. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8002914 [article] Automated generation of phase diagrams for binary systems with azeotropic behavior [texte imprimé] / Martín Cismondi, Auteur ; Michael L. Michelsen, Auteur ; Marcelo S. Zabaloy, Auteur . - 2009 . - p. 9728–9743. Chemistry engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 N° 23 (Décembre 2008) . - p. 9728–9743 Mots-clés : Automated  generation  Diagrams  Azeotropic  behavior Résumé : In this work, we propose a computational strategy and methods for the automated calculation of complete loci of homogeneous azeotropy of binary mixtures and the related Pxy and Txy diagrams for models of the equation-of-state (EOS) type. The strategy consists of first finding the system’s azeotropic end points (AEPs). These can exist on vapor−liquid (VL) critical lines (CAEPs), on liquid−liquid−vapor (LLV) lines (HAEPs), and on pure-compound vapor pressure lines (PAEPs). Next, for the chosen binary system, we generate one or two azeotropic lines. Each of these lines has, as its starting point, one of the previously identified AEPs. We calculate the azeotropic lines using a numerical continuation method that solves the nonlinear azeotropic system of equations under a range of conditions and efficiently tracks entire azeotropic curves. We have integrated our strategy for calculating azeotropic lines into a general algorithm for the single-run computation of binary global phase equilibrium diagrams (GPEDs). GPEDs are defined by pure-compound, critical, LLV, and azeotropic lines. We implemented this general algorithm in the computer program GPEC (Global Phase Equilibrium Calculations), which makes it possible to evaluate, at a glance, the behavior of a given model−parameter values combination, for a chosen model and binary system. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8002914

Cubic mixing rules / Marcelo S. Zabaloy in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5063–5079 Titre : Cubic mixing rules Type de document : texte imprimé Auteurs : Marcelo S. Zabaloy, Auteur Année de publication : 2008 Article en page(s) : p. 5063–5079 Note générale : Bibliogr. p. 5079 Langues : Anglais (eng) Mots-clés : Asymmetric  multicomponent  fluid  systems  Equation-of-state  Cubic  mixing  rules Résumé : The accurate description of thermodynamic properties of asymmetric multicomponent fluid systems of industrial interest, over a wide range of conditions, requires the availability of models that are both consistent and mathematically flexible. Specially suited models are those of the equation-of-state (EOS) type, which are built to represent the properties of liquids, vapors, and supercritical fluids. The composition dependence of EOSs is typically pairwise additive, with binary interaction parameters conventionally fit to match experimental information on binary systems. This is the case for the well-known van der Waals quadratic mixing rules (QMRs), which assume multicomponent system describability from binary parameters. In contrast, cubic mixing rules (CMRs) depend on binary and ternary interaction parameters. Thus, CMRs offer the possibility of increasing the model flexibility, i.e., CMRs are ternionwise additive. This means that, through ternary parameters, CMRs make it possible to influence the model behavior for ternary systems while leaving invariant the description of the corresponding binary subsystems. However, the increased flexibility implies the need for experimental information on ternary systems. This is so, unless we have a method to predict values for ternary parameters from values of binary parameters for the ternary subsystems not having ternary experimental information available, when we want to model the behavior of multicomponent fluids. Mathias, Klotz, and Prausnitz (MKP) [Fluid Phase Equilib. 1991, 67, 31−44] put forward this problem. In this work, we provide a possible solution, i.e., an equation to predict three index ternary parameters from three index binary parameters within the context of CMRs. Our equation matches the Michelsen−Kistenmacher invariance constraint and, in a way, has the pair-based MKP mixing rule in its genesis. The present approach can be extended also to models that are not of the EOS type. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071570b [article] Cubic mixing rules [texte imprimé] / Marcelo S. Zabaloy, Auteur . - 2008 . - p. 5063–5079. Bibliogr. p. 5079 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5063–5079 Mots-clés : Asymmetric  multicomponent  fluid  systems  Equation-of-state  Cubic  mixing  rules Résumé : The accurate description of thermodynamic properties of asymmetric multicomponent fluid systems of industrial interest, over a wide range of conditions, requires the availability of models that are both consistent and mathematically flexible. Specially suited models are those of the equation-of-state (EOS) type, which are built to represent the properties of liquids, vapors, and supercritical fluids. The composition dependence of EOSs is typically pairwise additive, with binary interaction parameters conventionally fit to match experimental information on binary systems. This is the case for the well-known van der Waals quadratic mixing rules (QMRs), which assume multicomponent system describability from binary parameters. In contrast, cubic mixing rules (CMRs) depend on binary and ternary interaction parameters. Thus, CMRs offer the possibility of increasing the model flexibility, i.e., CMRs are ternionwise additive. This means that, through ternary parameters, CMRs make it possible to influence the model behavior for ternary systems while leaving invariant the description of the corresponding binary subsystems. However, the increased flexibility implies the need for experimental information on ternary systems. This is so, unless we have a method to predict values for ternary parameters from values of binary parameters for the ternary subsystems not having ternary experimental information available, when we want to model the behavior of multicomponent fluids. Mathias, Klotz, and Prausnitz (MKP) [Fluid Phase Equilib. 1991, 67, 31−44] put forward this problem. In this work, we provide a possible solution, i.e., an equation to predict three index ternary parameters from three index binary parameters within the context of CMRs. Our equation matches the Michelsen−Kistenmacher invariance constraint and, in a way, has the pair-based MKP mixing rule in its genesis. The present approach can be extended also to models that are not of the EOS type. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071570b