A new generalized alpha function for a cubic equation of state Part 1. Peng-Robinson equation

Twu, Chorng H.; Coon, John E.; Cunningham, Jack R.

doi:10.1016/0378-3812(94)02601-v

Cited by 187 publications

(154 citation statements)

References 7 publications

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“…The deviations observed shows that the modified EOS proposed here is adequate and can be compared to the correlative capability of the equations of state proposed by Soave [2] and Peng and Robinson [3], besides to the results obtained by EOSs presented in [12], [6], [25][26], [14]. The adequate choice of an equation of state as well as generalized alpha function, associated to account the covolume temperature dependent, contributes to decrease the differences between experimental and calculated data of thermophysical properties of equilibrium.…”

Section: Resultssupporting

confidence: 53%

“…(2), (7) and (8), it is possible to observe a sensible improvement in the results when compared with deviations presented in [2][3], [5], [14], and [24]. This improvement can be attributed to the substitution of original repulsive term in equation (1) by Carnahan-Starling repulsion term, whose theoretical importance and correct representation of intermolecular repulsions behavior in real fluids is confirmed in several works in the literature [6], [13], and [15][16][17][18].…”

Section: Comparison Between Deviations In Experimental and Calculatedsupporting

confidence: 57%

“…In spite of its adequate format, several modifications in the original format of Peng and Robinson EOS [3] have been proposed such as: changes in its original alpha function, used to calculate attraction parameter temperature dependent [5][6], as well as to consider the co-volume temperature dependent [7][8][9]. All of resultant EOSs contribute for improvement of the phase equilibria calculations for both pure compounds and mixtures.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Comparative Study between Cubic and non-Cubic Equations of State Using Carnahan-Starling Repulsive Term: Application of Temperature-Dependent Alpha and Beta Functions

Checoni¹,

Aznar²

2014

Int. J. Thermo

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Studies on phase equilibria data behavior of pure substances are motivation to the researchers due to importance of these data for the scientific and industrial applications. Several EOS were proposed and its modifications have been made, whose aim is to improve the correlation between experimental and calculated thermophysical properties. This work proposes a comparative study between the PVT calculated data using cubic and non-cubic equations of state, in which its original repulsive term is substituted by the Carnahan-Starling hard-sphere repulsive term; furthermore, generalized expression to calculate (Tr,) and (Tr,) functions are used. Experimental data of vapor pressure for various pure compounds were compared to the calculated vapor pressure data showing satisfactory agreement, when this proposed modification is employed.

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Section: Resultssupporting

confidence: 53%

Section: Comparison Between Deviations In Experimental and Calculatedsupporting

confidence: 57%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Comparative Study between Cubic and non-Cubic Equations of State Using Carnahan-Starling Repulsive Term: Application of Temperature-Dependent Alpha and Beta Functions

Checoni¹,

Aznar²

2014

Int. J. Thermo

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“…The simple forms are a function only of temperature or of acentric factor whereas the more complex forms (Behar et al, 1985(Behar et al, , 1986Twu et al, 1995) increase the number of parameters.…”

Section: For Pure Component Vapour Pressure Improvementmentioning

confidence: 99%

Application to Petroleum Engineering of Statistical Thermodynamics – Based Equations of State

Hemptine¹,

Mougin²,

Barreau³

et al. 2006

Oil & Gas Science and Technology - Rev. IFP

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Résumé -Application des équations d'état basées sur la statistique thermodynamique, aux besoins pétroliers -L'utilité des équations d'état cubiques pour l'ingénieur pétrolier a été démontrée depuis de nombreuses années. Leur pouvoir prédictif reste cependant limité. De nouvelles équations d'état, basées sur des principes de mécanique statistique, ont été développées depuis environ 15 ans, et leur maturité est telle qu'elles sont maintenant de plus en plus utilisées par l'ingénieur. Dans cette publication, nous nous concentrerons essentiellement sur les équations qui ont pour base la théorie de Wertheim. Nous aborderons trois thèmes : Les mélanges associatifs tels l'eau et les alcools en présence d'hydrocarbures ont toujours représenté un défi majeur pour les équations d'état. Nous démontrons ici que l'équation CPA (SRK avec un terme associatif), tout en conservant les caractéristiques de la cubique pour les molécules non-associatives, améliore significativement le pouvoir prédictif de ces équations pour les mélanges contenant de l'eau, du méthanol et des hydrocarbures. La signification physique des paramètres de l'équation SAFT rend possible l'élaboration d'une méthode de contribution de groupe pour la détermination des paramètres de cette équation. En utilisant cette approche, il est possible de prédire les tensions de vapeur et les volumes liquide des molécules lourdes avec une précision remarquable. Nous montrons cela sur les n-alcanes, les n-alcools et les 1-oléfines, ainsi que pour les isomères méthyls des alcanes. Finalement, nous présenterons les prédictions d'équilibres liquide-vapeur de mélanges non-idéaux, obtenu par l'équation SAFT en incluant des termes polaires. Nous montrons ainsi clairement l'effet du quadrupole pour les mélanges aromatique-non-aromatique. Le fait de tenir compte ou non des interactions dipole-dipole permet de différencier le comportement des isomères cis-et trans oléfiniques. Abstract

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“…Compared to the original PR EoS, this alpha function uses a higher order polynomial function in the acentric factor for the m parameter that allows a better modelling of heavy-hydrocarbon phase behaviour. Twu et al, 1991Twu et al, , 1995aTwu et al, , 1995b proposed two different alpha functions. The first one requires -for each pure component -to fit the model parameters (N, M and L) on experimental pure-component VLE data:…”

Section: General Presentation Of Cubic Equations Of Statementioning

confidence: 99%

Thermodynamic Models for the Prediction of Petroleum-Fluid Phase Behaviour

Privat¹,

Jaubert²

2012

Crude Oil Emulsions- Composition Stability and Characterization

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A new generalized alpha function for a cubic equation of state Part 1. Peng-Robinson equation

Cited by 187 publications

References 7 publications

Comparative Study between Cubic and non-Cubic Equations of State Using Carnahan-Starling Repulsive Term: Application of Temperature-Dependent Alpha and Beta Functions

Comparative Study between Cubic and non-Cubic Equations of State Using Carnahan-Starling Repulsive Term: Application of Temperature-Dependent Alpha and Beta Functions

Application to Petroleum Engineering of Statistical Thermodynamics – Based Equations of State

Thermodynamic Models for the Prediction of Petroleum-Fluid Phase Behaviour

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