A new equation of state for polar and nonpolar pure fluids

A correlation is presented for the thermodynamic properties of pure fluids containing small or large molecules. The residual Helmholtz energy is given in terms of perturbed-hard-chain (PHC) theory, extended to polar fluids with a multipolar expansion. The novel feature of this correlation is a separation of the Helmholtz energy into low-density and high-density contributions. The low-density contribution follows from a virial expansion and the high-density contribution from a perturbation expansion. For intermediate densities, a continuous function is used to interpolate between the two density limits. This modification of PHC theory improves agreement with experimental second virial coefficients, vapor pressures, and saturated liquid densities. Since all molecular parameters used here have a well-defined physical significance, they can be reliably estimated for high-molecular-weight-fluids where experimental data are scarce. More important, separation into low-density and high-density contributions allows separate mixing rules for each density region; this flexibility in mixing rules significantly improves representation of mixture properties, as discussed in Part II.

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“…and Chung et al (1984). These equations use a third molecular parameter in addition to the two of the simple van der Waals theory.…”

Section: Introductionmentioning

confidence: 99%

Molecular thermodynamics for fluids at low and high densities. Part I: Pure fluids containing small or large molecules

1986

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“…Several EOSs based on perturbed hard-sphere EOSs have been proposed (Carnahan and Starling, 1969;Nakamura et al, 1976;Lin et al, 1983;Chung et al, 1984;Guo et al, 1985;Bryan and Prausnitz, 1987;Mulia and Yesavage, 1989). Shah (1992) and Shah et al (1994) developed a four-parameter perturbed hard-sphere EOS which is a generalized quartic EOS, by combining a repulsive term, fitted to the molecular dynamics data of Alder and Wainwright (1960), with an empirical attractive term.…”

Section: Introductionmentioning

confidence: 99%

Extension of a generalized quartic equation of state to pure polar fluids

Lin¹,

Bienkowski²,

Shah³

et al. 1996

AIChE Journal

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Evaluation of the local composition model for VLE of binary mixtures of triethylene glycol with methane, water and benzene

1996

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This work evaluated the predictive accuracy of the local composition model (LCM) formulation developed by Li et al. (1986) for four binary, vapor‐liquid equilibria (VLE) mixtures. The four components comprising these mixtures were benzene, triethylene glycol (TEG), water and methane, while the mixtures examined in this work were the benzene‐TEG, water‐TEG, methane‐TEG and methane‐benzene systems. The Khan‐Chung‐Lee‐Starling (KCLS) equation of state developed by Chung et al. (1984) was used with the LCM to predict the VLE behavior of these systems. The accurate results obtained in this work may be applied to the design of natural gas dehydration processes.

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A new equation of state for polar and nonpolar pure fluids

Cited by 17 publications

References 30 publications

Molecular thermodynamics for fluids at low and high densities. Part I: Pure fluids containing small or large molecules

Molecular thermodynamics for fluids at low and high densities. Part I: Pure fluids containing small or large molecules

Extension of a generalized quartic equation of state to pure polar fluids

Evaluation of the local composition model for VLE of binary mixtures of triethylene glycol with methane, water and benzene

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