Modelling of the equilibrium properties of the system H3PO4–H2O: representation of VLE and liquid phase composition

Cherif, Mourad; Mgaidi, Arbi; Ammar, M.; Abderrabba, Manef; Fürst, Walter

doi:10.1016/s0378-3812(00)00458-1

Cited by 24 publications

(15 citation statements)

References 21 publications

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“…1,2) Moreover, in spite of its high viscosity, liquid phosphoric acid has high proton conductivity, which makes it useful as fuel cell electrolytes. Therefore, many experimental and theoretical studies have been carried out on the liquid phase [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] as well as on the monomer [21][22][23] ( Fig. 1), crystal, [24][25][26] and the polymeric gels [27][28][29][30] of phosphoric acid.…”

Section: Introductionmentioning

confidence: 99%

Ab InitioMolecular-Dynamics Simulation of Concentrated Phosphoric Acid

Tsuchida

2006

J. Phys. Soc. Jpn.

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We have investigated the properties of 100% phosphoric acid (H 3 PO 4 ) in the liquid state by the combination of gradient-corrected density-functional theory and norm-conserving pseudopotentials. Various structural properties as well as the vibrational density of states have been calculated through molecular-dynamics simulations under the Born-Oppenheimer approximation. Proton transfer is found to occur frequently between adjacent PO 4 groups along the OH···O hydrogen bonds, which makes the single and double bonds indistinguishable.

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Section: Introductionmentioning

confidence: 99%

Ab InitioMolecular-Dynamics Simulation of Concentrated Phosphoric Acid

Tsuchida

2006

J. Phys. Soc. Jpn.

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“…They simply include a correction of the osmotic coefficient to integrate the partial dissociation. This model was improved by Cherif et al [27], who introduced additional complex ions based on Raman spectroscopy measurements [64].…”

Section: Discussionmentioning

confidence: 99%

“…Indeed, rather than high order virial coefficients, Pitzer and Silvester [24] introduced a neutral species that comes from the partial dissociation of phosphoric acid. Later, several authors successfully included the HPO 4 0 (aq) species [25][26][27] to describe the behavior of the phosphoric acid system up to 24 molÁkg -1 using either the original Pitzer's model or the modified Pitzer's model [28]. In our model for NaOH-H 2 O at high temperature and high salinity, it was necessary to introduce the neutral species NaOH 0 (aq).…”

Section: Theoretical Backgroundmentioning

confidence: 99%

A New Pitzer Parameterization for the Binary NaOH–H2O and Ternary NaOH–NaCl–H2O and NaOH–LiOH–H2O Systems up to NaOH Solid Salt Saturation, from 273.15 to 523.15 K and at Saturated Vapor Pressure

et al. 2015

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This paper presents a new set of Pitzer ion interaction model parameters for the binary NaOH-H 2 O system for concentrations up to over 30 molÁkg -1 and temperatures ranging from 273.15 to 523.15 K. Assuming that the electrolyte is only partially dissociated, the model requires the adjustment of (i) the three classical binary interaction parameters b (0) , b (1) and C / , (ii) the equilibrium constant of formation of the aqueous complex NaOH 0 (aq), and iii) one binary (k NaOH/NaOH ) and one ternary (f NaOH=Na þ =OH À ) interaction parameter. This approach, which provides much better results than the approach of treating NaOH as a fully dissociated electrolyte, was chosen to extend the description of the system to high temperatures and high concentrations. The temperature functions of the solubility products of anhydrous NaOH(cr) and five hydrated salts, NaOHÁnH 2 O(cr) (where n = 1, 2, 3.11, 3.5, 4a), were determined. In order to evaluate the quality of the new set of Electronic supplementary material The online version of this article (parameters, several tests were run on various properties using various literature data. These include the boiling point elevation in the NaOH-H 2 O system and the phase diagrams of the two ternary systems NaOH-NaCl-H 2 O and NaOH-LiOH-H 2 O. Interaction parameters for the two related binary systems NaCl-H 2 O and LiOH-H 2 O were taken from previous studies. To ensure consistency, four new mixing parameters were revised (f Na þ =Cl À =NaOH and W Cl À =OH À =Na þ for the ternary system NaOH-NaCl-H 2 O and k Li þ =NaOH and W OH À =Na þ =Li þ for the ternary system NaOH-LiOH-H 2 O). Consistent with Pitzer's equations, our new set of parameters can be used to satisfactorily describe the quaternary Na ? -Li ? -Cl --OH --H 2 O system to very high concentrations and temperatures.

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“…It is, in principle, possible to adapt these procedures to solve isothermal flash-like problems involving electrolyte systems and there are several examples of vapor-liquid equilibrium computations for electrolyte systems that use Gibbs free energy minimization (Cherif et al, 2000(Cherif et al, , 2002. An example with solid phases is a Gibbs free energy minimization method that uses simple thermodynamic phase models (ideal K-values) to predict gas hydrate precipitation (Ballard and Sloan, 2004) in systems that contain salts.…”

Section: Introductionmentioning

confidence: 99%

A reliable procedure to predict salt precipitation in pure phases

Beltrão

Cardoso

Castier³

2010

Braz. J. Chem. Eng.

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-This article proposes a new procedure to compute solid-liquid equilibrium in electrolyte systems that may form pure solid phases at a given temperature, pressure, and global composition. The procedure combines three sub-procedures: phase stability test, minimization of the Gibbs free energy with a stoichiometric formulation of the salt-forming reactions to compute phase splitting, and a phase elimination test. After the phase splitting calculation for a system configuration that has a certain number of phases, the phase stability test establishes whether including an additional phase will reduce the Gibbs free energy further. The criteria used for phase stability may lead, in some cases, to the premature inclusion of phases that should be absent from the final solution but, if this happens, the phase elimination sub-procedure removes them. It is possible to use the procedure with several excess Gibbs free energy models for liquid phase behavior. The procedure has proven to be reliable and fast and the results are in good agreement with literature data.

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Modelling of the equilibrium properties of the system H3PO4–H2O: representation of VLE and liquid phase composition

Cited by 24 publications

References 21 publications

Ab InitioMolecular-Dynamics Simulation of Concentrated Phosphoric Acid

Ab InitioMolecular-Dynamics Simulation of Concentrated Phosphoric Acid

A New Pitzer Parameterization for the Binary NaOH–H2O and Ternary NaOH–NaCl–H2O and NaOH–LiOH–H2O Systems up to NaOH Solid Salt Saturation, from 273.15 to 523.15 K and at Saturated Vapor Pressure

A reliable procedure to predict salt precipitation in pure phases

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