Correlation of thermodynamic properties of fluids by means of equations of state

Alessi, Paolo; Bertucco, Alberto; Fermeglia, Maurizio

doi:10.1016/0040-6031(88)87462-8

Cited by 2 publications

(4 citation statements)

References 36 publications

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“…It is recognized in the literature that at low pressures the equations of state of the van der Waals type with the modified attractive term have better ability in correlating the thermodynamic properties of fluids than the equations with the modified repulsion term [33]. The results obtained in the present study clearly demonstrate that, at high densities the situation is opposite, the ability of an equation of state to describe properly the properties for a substance mainly depends on the form of the repulsive part of the equation, the modification of the attractive part does not give significant improvements.…”

Section: Discussionmentioning

confidence: 99%

Thermodynamic Testing of Equations of State of Dense Simple Liquids

Randzio

Deiters

1995

Ber Bunsenges Phys Chem

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The isobaric thermal expansivities (a p ) of n-hexane and of methane measured over large pressure and temperature ranges have been proposed as a thermodynamic property test for theoretical and semi-empirical equations of state for simple liquids at high densities. The correlation equations for a (P, T) and the coordinates of the crossing point of isotherms of a p are given for both substances. A number 6f selected equations of state with vario~s m~~ifications of the attractive and repulsive contribution to the pressure have been tested with respect t? their ability t? repro~u.ce the proposed test property. The analysis has revealed that at high densities the equanons of state with modified repulsive term reproduce the test property better than the equations with modified attractive term. A reproduction of the most characteristic feature of the test property, the crossing of isotherms of a p can be only obtained with equations in which the repulsion term is made softer than the simple rigidsphere term R TI( Vm -b). The best reproduction of the test property was obtained with the soft-sphere equation constructed on 8-4 Lennard-Jones intermolecular pair potential. The anisotropy in molecular shape of n-hexane and methane has only a little influence on the results of testing.1179

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Section: Discussionmentioning

confidence: 99%

Thermodynamic Testing of Equations of State of Dense Simple Liquids

Randzio

Deiters

1995

Ber Bunsenges Phys Chem

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“…The almost infinite number of possible mixtures and wide range of temperature and pressure encountered in process engineering are such that no single thermodynamic model is ever likely to be applicable in all cases. Consequently, knowledge and judgment are required to select the most appropriate methods by which to estimate the conditions under which two phases will be in equilibrium [11].…”

Section: Improvement Of Equation Of State and Activity Coefficients M...mentioning

confidence: 99%

“…Values of the constants A, B and C which appear in this equation are shown in Table (B-1) in Appendix B [11,24].…”

Section: T Bmentioning

confidence: 99%

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Isobaric Vapor - Liquid Equilibria of Gasoline Additives Systems At 101.3 kPa

Farhod Chasib Al-Jiboury,

Khamas

2010

ETJ

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In this study, isobaric vapor-liquid equilibrium of gasoline additives for three ternary systems: "MTBE + Ethanol + 2-Methyl-2-propanol", "Ethanol + 2-Methyl-2-propanol + Octane", and "MTBE + Ethanol + Octane" at 101.3kPa are studied. Furthermore three binary systems: "ethanol + 2-Methyl-2-propanol", "MTBE + Ethanol", and "MTBE + Octane" at 101.3 kPa have been studied.The binary system "MTBE + Ethanol" forms minimum boiling azeotrope. The azeotrope data are x 1 (AZ) =0.955 mole fraction and T(AZ) =327.94 K. The other ternary systems and the other binary systems do not form azeotrope.All the literature data used passed successfully the test for thermodynamic consistency using McDermott-Ellis test method.In this study the calculation of VLE K -values is done by using three methods, the first method uses modified Soave Redlich and Kwong (SRK), modified Peng and Robinson (PR) equations of state for two phases. The second method uses SRK-EOS for vapor phase with (NRTL, UNIQUAC and UNIFAC activity coefficient models) for liquid phase and using PR-EOS for vapor phase with (NRTL, UNIQUAC and UNIFAC activity coefficient models) for liquid phase. The third method uses the Wong-Sandler mixing rules and the PRSV-EOS based on GE of (NRTL and UNIQUAC activity coefficient models).The non ideality of both vapor and liquid phases for the literature data for the ternary and binary systems have been accounted for predicting VLE K -values using the maximum likelihood principle for parameter estimation which provides a mathematical and computational guarantee of global optimality in parameters estimation. The Wong-Sandler mixing rules and the PRSV-EOS based on excess Gibbs free energy G E of NRTL activity coefficient model give more accurate results for correlation and prediction of the K-values than other methods for the ternary and binary systems which contain asymmetric and polar compounds.

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Correlation of thermodynamic properties of fluids by means of equations of state

Cited by 2 publications

References 36 publications

Thermodynamic Testing of Equations of State of Dense Simple Liquids

Thermodynamic Testing of Equations of State of Dense Simple Liquids

Isobaric Vapor - Liquid Equilibria of Gasoline Additives Systems At 101.3 kPa

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