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Phase equilibrium diagrams of fluid phases in ternary systems can have a high complexity. In this work, a strategy and calculation methods for the computation of complete sections of ternary fluid phase equilibrium surfaces is proposed. To illustrate the methodology, we present computed results for the fluid phase equilibrium of an isothermal section for the ternary highly non-ideal system CO2+H2O+2-propanol(IPA), as described by a given model and given set of values of the model parameters. The calculation method is based on the prior identification of (univariant) key points (KPs) of the ternary isotherm. From such KPs, it is possible to build the different equilibrium lines that constitute the ternary isothermal diagram, with the help of a numerical continuation method. The results show a high level of complexity including a number of three-phase loci, critical loci, and ternary critical endpoints, together with a ternary four-phase equilibrium point. Fil: Pisoni, Gerardo Oscar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahia Blanca. Planta Piloto de Ingeniería Química (I). Grupo Vinculado al Plapiqui - Investigación y Desarrollo en Tecnología Química; Argentina. Universidad Nacional del Sur. Departamento de Ingeniería Química; Argentina. Universidade Estadual de Maringa; Fil: Cismondi Duarte, Martín. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahia Blanca. Planta Piloto de Ingeniería Química (I). Grupo Vinculado al Plapiqui - Investigación y Desarrollo en Tecnología Química; Argentina Fil: Zabaloy, Marcelo Santiago. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; Argentina. Universidad Nacional del Sur. Departamento de Ingeniería Química; Argentina Fil: Cardozo Filho, Lucio. Universidade Estadual de Maringa; Brasil

The RKPR EoS was developed in the past decade as a three-parameter model, with the intention to overcome some of the limitations of classic two-parameter cubic equations of state. More recently, parameter correlations were presented for alkanes and their mixtures, showing excellent capacity to predict the fluid phase behavior of binary mixtures up to the more asymmetric combinations and in wide ranges of temperature and pressure. In this work, different types of phase equilibrium data for multicomponent mixtures are considered, in order to see whether the good performance previously demonstrated for binary systems is also transferable to multicomponent mixtures like the ones typically encountered in synthetic fluids designed in the lab as model reservoir fluids. In the case of ternary systems with good availability of constant temperature and pressure data sets, the type and behavior of these Gibbs triangle diagrams are analyzed with reference to the general or global behavior of the system, based on pure compound saturation and binary critical lines, something we had not found in the literature preceding this work. The results and comparisons presented in this article allow concluding that RKPR2015 can be a useful tool with very good predictive capacity to describe the fluid phase equilibria of hydrocarbon mixtures. Advantages over the Peng-Robinson equation appear more clearly for the more asymmetric fluids, including synthetic gas condensates. Fil: Tassin, Natalia Giselle. Universidad Nacional de Córdoba. Instituto de Investigación y Desarrollo en Ingeniería de Procesos y Química Aplicada. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigación y Desarrollo en Ingeniería de Procesos y Química Aplicada; Argentina Fil: Mascietti, Vanessa A.. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales; Argentina. Universidade Federal do Rio de Janeiro; Brasil Fil: Cismondi Duarte, Martín. Universidad Nacional de Córdoba. Instituto de Investigación y Desarrollo en Ingeniería de Procesos y Química Aplicada. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigación y Desarrollo en Ingeniería de Procesos y Química Aplicada; Argentina

Thermodynamic description of the ternary Cu-Mg-Sn system at its Cu-Mg side is presented. The thermodynamic parameters of the binary sub-systems, Cu-Mg, Cu-Sn and Mg-Sn, are taken from the earlier SGTE-based assessments (modifying the Mg-Sn description slightly) and those of the Cu-Mg-Si system are optimized in this study using the experimental thermodynamic and phase equilibrium data. The solution phases of the systems are described with the substitutional solution model and the intermetallic Cu2Mg compound (Laves C15), treated as simple semi-stoichiometric phases of the (A,B)pCq type, is described with the twosublattice model. The present ternary description is valid for tin contents up to 45 wt% (xSn?0.30).

Prediction of bulk metallic glass (BMG) forming compositions has always been a challenge due to thermodynamic and kinetic constraints. In the present investigation, a parameter based on the enthalpy of chemical mixing (?Hchem) and the mismatch entropy (?S?/ kB) has been used to correlate with glass forming ability in some Zr based BMGs. The new thermodynamic parameter, PHS = ?H chem � ?S?/kB, is found to have strong correlation with glass forming ability in the configurational entropy (?Sconfig/R) range of 0.9-1.0. PHS has been calculated for compositions in Zr-Cu-Ag, Zr-Cu-Al, Zr-Cu-Ti and Zr-Cu-Ga ternary systems. It is observed that in all the systems studied, the best BMG composition (highest critical diameter (Zc) of glass formation) is the one that corresponds to the highest negative PHS value. Present approach using PHS could be road map to design new BMG forming compositions. � 2011 Elsevier B.V. All rights reserved.

A thermodynamic model parameter P H-S, which is a product of enthalpy of chemical mixing and mismatch entropy normalized by Boltzmann's constant, was used as a guiding tool to predict amorphous phase forming compositions in Fe-rich alloys of the Fe-Zr-B system. Attempts were made to evaluate the effect of Zr addition on the P H-S parameter and phase formation by mechanical alloying (MA) and rapid solidification processing (RSP). A systematic evaluation of the P H-S parameter of various binary compounds in the Fe-Zr-B system and ternary alloys indicated ?-7 kJ/mol as a lower bound for the formation of amorphous phase. Model predictions were verified with phase formation in two random compositions in the Fe-rich end of the Fe-Zr-B system synthesized by MA and RSP. � 2011 The Minerals, Metals & Materials Society and ASM International.

The danger of the formation of flakes has been considered from the position of the estimation of the maximum pressure of gaseous hydrogen in micropores of the alloy, whose magnitude is substantially affected by the solubility of hydrogen at P = 1 atm. The hydrogen solubility can be increased sharply by the introduction of additions of elements which strongly interact with hydrogen. In our article this effect is examined based on the example of additions of palladium to steel, which has for the first time been experimentally studied by Arkharov. A statistical model of a ternary alloy with strongly interacting substitutional and interstitial atoms has been developed. An equation of hydrogen solubility has been derived, which contains, besides the concentration of substitutional atoms, a single energy parameter ε equal to the difference in the energies of interaction of Pd-H and Fe-H pairs. A comparison of the theoretical expression for the solubility with the experimental data made it possible to determine that ε = -22.5 kJ/mol. A specific feature of hydrogen solubility in Fe-Pd alloys consists in the fact that the reduction in the solubility below 400 K, which is common for iron and steels, is changed by a solubility increase caused by the accumulation of hydrogen atoms near palladium atoms (acting as traps), which is the main factor responsible for an increase in the hydrogen solubility and a sharp decrease in the hydrogen pressure in micropores. © 2009 Pleiades Publishing, Ltd.

The results of the phase relations near ternary eutectic point in the Ag-In-Sb system are investigated in this paper. Phase equilibrium calculation was done using Thermocalc software and experimental DTA results for the chosen alloys in the isopleths with molar ration of In:Sb = 7:3; 9:1 and 1:1. The structural characteristics of these alloys have been investigated using light optic microscopy and scanning electron microscopy, while hardness measurements have also been done. Solidification path for three ternary alloys located on three different investigated isopleths was calculated using Pandat software.

Phase diagrams of ternary blends of poly(phenylene ether) (PPE, M n = 1.2 and 12 kg mol-1), polystyrene (PS, Mn = 22.5 kg mol-1), and diglycidyl ether of bisphenol A (DGEBA) were experimentally obtained in an extended range of temperatures and fitted with the Flory-Huggins model using three binary interaction parameters. A significant increase in miscibility together with the appearance of an immiscibility loop was found for PPEs with Mn values comprised in the range between 1 and 10 kg mol-1. This enables us to obtain initial homogeneous solutions in regions of high DGEBA concentrations, a possibility that was not previously reported for this ternary blend. This opens new possibilities for the toughening of epoxies replacing a single thermoplastic with a thermoplastic blend where both components (PS and PPE) are completely miscible. Fil: Soulé, Ezequiel Rodolfo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; Argentina Fil: Fine, T.. Institut National des Sciences Applique´s de Lyon; Francia Fil: Borrajo Fernandez, Julio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; Argentina Fil: Williams, Roberto Juan Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; Argentina Fil: Pascault, J.P.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; Argentina

An extension of Barker's method to ternary systems is briefly outlined. Expressions for the standard deviations of the excess molar Gibbs free energy and the equilibrium pressure as functions of composition are obtained. These expressions are applied to accurate experimental data for the cryogenic (liquid) mixture CH3F+N2O+Xe recently measured in our laboratory. http://www.sciencedirect.com/science/article/B6TG2-3VGSGDR-4/1/e3c29abb1f0602ee677ab2a9887b8eee

International audience; Accurate knowledge of the compositions of the equilibrium phases in the systems containing gas hydrates is essential for many hydrate-based separation processes. Unfortunately, there are limited sets of such experimental data available in the literature partly due to the difficulties in measurements of the compositions of the phases in equilibrium with gas hydrate. Consequently, satisfactory accuracy of the measurements may not be obvious. Therefore, reliability of the corresponding data should be checked prior to their further applications. In this article, we present a thermodynamic assessment test (consistency test) based on the area test approach for the experimental compositional data of vapor phase in equilibrium with gas hydrate + liquid water for the carbon dioxide + methane or nitrogen + water system. The van der Waals and Platteeuw (vdW-P) solid solution theory is used to model the hydrate phase, and the Valderrama-Patel-Teja equation of state (VPT-EoS) along with the nondensity dependent (NDD) mixing rule is applied to deal with the fluid phases. The results show that only one of the studied experimental data sets seems to be thermodynamically consistent, and the rest of the data seem to be either not fully consistent or inconsistent.

The diffusion profiles and the reaction paths in ternary solid solutions are determined by both thermodynamics and kinetics. The matrix of the diffusion coefficient can be described as the product of the Hessian matrix for the thermodynamic influences and the Onsager matrix for kinetic influences. In this paper the interest is focused on the influence of the ideal part of the Hessian matrix, i.e. the ideal mixing entropy on interdiffusion. The ideal diffusion profiles are calculated by a computer simulation and they are compared with experimental results from the literature. These comparisons reveal that in most cases the qualitative shape of the diffusion profiles and of the reaction paths can be considered as caused by the ideal mixing entropy. Surprisingly, the shape of the diffusion profiles turns out to depend on the component that was chosen as the so-called solvent of the ternary mixture. This means that the ideal reaction paths do not show the triangular symmetry expected for an ideal ternary system. Especially, reaction paths between starting positions showing the same concentration of one of the three components do not run along straight lines.

A thermodynamic description of the Mo-Ni-Ti system is obtained by combining results of first-principle total energy calculations with the CALPHAD approach. The enthalpies of formation of binary intermediate phases are calculated by first-principle method employing ultra-soft pseudopotentials with plane wave basis set, which are compared with the experimental data. The energy of formation of hypothetical end-members due to the sublattice model used for modeling the ternary solubility in the binary phases Ni3Ti, NiTi, and MoNi3 are also calculated by first-principle method and incorporated in the modeling of those phases. Gibbs energy parameters for equilibrium phases in the Mo-Ni-Ti system are obtained by optimization of published experimental data, by combining it with thermodynamic descriptions of the limiting binaries from the literature. The liquidus projection, isothermal and vertical sections are calculated and compared with corresponding experimental information. � 2010 Elsevier Ltd. All rights reserved.

International audience; In this work, we use an efficient and reliable "dynamic- synthetic" method for the measurement of critical properties of a variety of pure compounds, binary mixtures, and one ternary mixture. The critical phenomenon is observed via the critical opalescence in a view cell, which withstands conditions up to 543 K and 20 MPa. Excellent agreements were obtained between the measured pure compounds' properties and those listed in recent databases. Among the pure compounds measured, several refrigerants less well described in open literature (C 3F 6, C 3F 6O, R365mfc) have been compared with conventional predictive models. The critical profiles of associating, azeotropic systems ethanol + n-alkanes (C 4-C 8) are presented, as well as the critical surfaces for the ternary system n-pentane + ethanol + n-hexane. We present forms of the Cibulka and Singh's equation suitable for correlating ternary critical properties.

International audience; The viscosity of the binary system 1-propanol + toluene has been measured with a falling-body viscometer for seven compositions as well as for the pure alcohol in the temperature range (293.15 to 353.15) K and up to 100 MPa with an experimental uncertainty of ± 2 %. At 0.1 MPa, the viscosity has been measured with a classical capillary viscometer (Ubbelohde) with an uncertainty of ± 1 %. A total of 216 experimental data points are reported. The viscosity behavior of this binary system is interpreted as the results of changes in the free volume and the breaking or weakening of hydrogen bonds. These data have been used to study the performance of two compositional models and a free-volume model.

Phosphogypsum is a waste by-product of the phosphate fertilizer industry, which is usually disposed in the environment because of its restricted use in industrial applications. Physico-chemical conditions existing in stack fluids and leachates are of major importance and determine solubility and redox stability of phosphogypsum, as well as radionuclide release from stacks to terrestrial environments. The aim of this study is to assess the effect of key parameters (e.g. ionic strength, temperature, pH) on the solubility of phosphogypsum. Phosphogypsum sampling and in-situ measurements were carried out at a coastal stack in Cyprus, solubility experiments were performed in simulated laboratory systems and thermodynamic calculations by means of MINTEQA2, an equilibrium speciation model. Generally, increasing ionic strength and temperature leads to increased phosphogypsum solubility, with the former being much more effective. The increased solubility of phosphogypsum in saline solutions is attributed solely to ionic strength effects on the activity of ionic species in solution and no solid phase transformations could be observed. The effect of pH on phosphogypsum solubility seems to be insignificant at least in a pH range between 4 and 8. Regarding uranium levels, there is a strong correlation between salinity and uranium concentration and linear correlation between phosphogypsum solubility and uranium levels in stack solutions, indicating the incorporation of uranium into the gypsum lattice and the formation of a solid solution. © 2009 Elsevier Ltd. All rights reserved. 100 10 854 857 Cited By :11

Flue gas is greatly responsible for acid rain formation and global warming. New generation ionic liquids (ILs) have potential in controlling the flue gas emissions, as they acquire high absorptivity for the component gases SO 2, CO2, etc. The association of the IL-gas interactions to the absorptivity of gas molecules in ILs is, however, poorly understood. In this paper, we present a molecular level description of the interactions of ILs with SO2, CO2, and N2 and show its implications to the differential gas solubility. Our results indicate that the IL anion-gas interactions play a key role in deciding the gas solubility in ILs, particularly for polar gases such as SO2. On the other hand, regular solution assumption applies to N2 solubility. In accordance with the previous theoretical and experimental findings, our results also imply that the IL anions dominate the interactions with gas molecules while the cations play a secondary role and the underlying fluid structures of the ILs remain unperturbed by the addition of gas molecules. � 2009 American Chemical Society.

International audience; In this communication, we examine the possibility of clathrate hydrate formation of toluene and o-, m-, or p-xylene with methane as help gas. An isochoric pressure-search method was used to measure hydrate phase equilibrium boundaries. The reliability of this method is tested by generating hydrate phase equilibrium boundary data for the methane-benzene-water system and comparing them with experimental data reported in the literature. The acceptable agreements demonstrate the reliability of the technique used in this work. The new experimental data of hydrate phase equilibrium boundary for the methane-(toluene/(o/m/p)- xylene)-water systems are compared with some selected experimental data from the literature for the methane-water system to study the possibility of shifting the hydrate phase equilibrium boundary of the latter system by the presence of toluene and o-, m-, or p-xylene. It is shown that toluene and o-, m-, or p-xylene have little or almost no effect on the hydrate phase equilibrium boundary of the methane-water system.

A simple genetic algorithm for the numerical evaluation of binodal curves in ternary systems polymer–liquid (1)–liquid (2) and polymer (1)–polymer (2)–solvent is presented. The technique exploits a specifically developed restarting technique based on a combined elitist and zooming strategy on the last population at each iteration. The objective function (fitness) is represented by the weighted sum of the squared differences of chemical potentials of the two phases of each component, obtained evaluating first derivatives of Gibbs free energy of the mixture with respect to the number of moles of the components. The method proposed (a) is numerically stable since it does not require the evaluation of first derivatives of the objective function and (b) can be applied in a wide range of cases changing the equation of state. Several comparisons with simplified iterative procedures presented in the past in the technical literature both for mixtures of two polymers with identical characteristics in a solvent and for mixtures of solvent–nonsolvent–polymer with solvent–polymer interaction parameter equal to zero are reported. Finally, a comparison between present results and the “alternating tangent approach” is reported for two technically meaningful binary systems, when a simplified PC-SAFT equation of state is adopted. The comparisons show that reliable results can be obtained by means of the algorithm proposed and suggest that the procedure presented can be used for practical purposes. © 2007 Wiley Periodicals, Inc. J Comput Chem, 2007

In order to study equilibrium segregation, composition profiles around coherent (1 0 0) interfaces in ternary fee systems were calculated using the cluster variation method within the tetrahedron approximation. A comparison with a previous regular-solution (RS) based model was made for interfaces between two disordered phases. This RS model overestimates the maximum atomic fraction of the segregant at the interface when its bulk value is >0.1. The oscillatory decay in segregant concentration from its maximum at the interface to its bulk value is much less damped in the case of the RS model. Analysis of the damping behavior leads to a very good agreement with results from free energy expansion approximations. Finally, the CVNI calculations were extended to interfaces between ordered ternary fee phases or anti-phase boundaries. Results for the interface between the L1(2)-Cu3Au(Ag) phase and a disordered Ag-rich phase in equilibrium at 583 K, and for a non-conservative APB in the same alloy, point to a strong suppression of order near the interfaces. (C) 2003 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

The thermodynamic properties and the T-x phase diagrams for liquid-solid equilibrium in II-VI and IV-VI ternary systems are described by a regular associated liquid solution model derived from that used by Jordan for ZnTe and CdTe and by the regular approximation for the solid solution. For the pseudo-binary systems exhibiting miscibility in both phases and monotonic variation of the liquidus and solidus curves, a general expression is obtained. It is independent of the interactions in the liquid, and is the same as for ideal non associated liquids. In the calculation of the ternary T-x phase diagrams five parameters are needed : the two interaction parameters α 1, α2, the two coefficients of dissociation, β 1, β2, obtained from the respective binary liquidus, and the interaction parameter W in the solid, derived from the pseudo-binary phase diagrams. Good agreement with experimental data is obtained for the pseudo-binary systems : ZnTe-CdTe, ZnTe-HgTe, ZnSe-ZnTe, CdTe-HgTe, CdTe-CdSe, HgTe-HgSe, PbSe-PbTe, PbTe-SnTe, and for the ternary systems : Zn-Cd-Te and Pb-Sn-Te. The theory is especially suited for the case β ≃ 0 and α is small. It is applied to the calculation of the chalcogen-rich part of the ternary systems : Cd-Hg-Te and Cd-Se-Te.

This work describes the energy and exergy analysis of a diesel engine integrated with a PCM based energy storage system, and provides more realistic and meaningful assessment than the conventional energy analysis. Using actual system data, the assessments of energy and exergy saved, and energy and exergy efficiencies are done. The exergy saved in the overall system is quantified and illustrated using an exergy flow diagram. Also, energy and exergy flow diagrams are compared. It is observed through the analysis that 6.13% of the total energy of the fuel is saved using the TES system. From the exergy analysis, it is identified that only 0.47% of the chemical availability of the fuel is saved. The energy efficiency of the integrated system is found to be varying between 3.19% and 34.15%. In contrast, the exergy efficiency, which incorporates the second law of thermodynamics for the integrated system, ranges from 0.25% to 27.41%.