Thermodynamic Properties of Gas Mixtures Containing Common Polar and Nonpolar Components

Nakamura, Ryoji; Breedveld, G. J. F.; Prausnitz, John M.

doi:10.1021/i260060a015

Cited by 75 publications

(40 citation statements)

References 6 publications

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“…[8,17,18]. In general, these equations showed better or comparable performance to the PR and SRK equations in calculating fluid phase equilibrium properties of simple mixtures.…”

Section: The Repulsive Termmentioning

confidence: 81%

Phase Behavior of Light Gases in Hydrocarbon and Aqueous Solvents

Gasem¹,

Robinson²

1998

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Under previous support from the Department of Energy, an experimental facility has been established and operated to measure valuable vapor-liquid equilibrium data for systems of interest in the production and processing of coal fluids. To facilitate the development and testing of models for prediction of the phase behavior for such systems, we have acquired substantial amounts of data on the equilibrium phase compositions for binary mixtures of heavy hydrocarbon solvents with a variety of supercritical solutes, including hydrogen, methane, ethane, carbon monoxide, and carbon dioxide.The present project focuses on measuring the phase behavior of light gases and water in Fischer-Tropsch (F-T) type solvents at conditions encountered in indirect liquefaction processes and evaluating and developing theoretically-based correlating frameworks to predict the phase behavior of such systems. Specific goals of the proposed work include (a) developing a state-ofthe-art experimental facility to permit highly accurate measurements of equilibrium phase compositions (solubilities) of challenging F-T systems, (b) measuring these properties for systematically-selected binary, ternary and molten F-T wax mixtures to provide critically needed input data for correlation development, (c) developing and testing models suitable for describing the phase behavior of such mixtures, and (d) presenting the modeling results in generalized, practical formats suitable for use in process engineering calculations.During the present period, the Park-Gasem-Robinson (PGR) equation of state (EOS) has been modified to improve its volumetric and equilibrium predictions. Specifically, the attractive term of the PGR equation was modified to enhance the flexibility of the model, and a new expression was developed for the temperature dependence of the attractive term in this segmentsegment interaction model.The predictive capability of the modified PGR EOS for vapor pressure, and saturated liquid and vapor densities was evaluated for selected normal paraffins, normal alkenes, cycloparaffins, light aromatics, argon, carbon dioxide and water. The generalized EOS constants and substance-specific characteristic parameters in the modified PGR EOS were obtained from the pure component vapor pressures, and saturated liquid and vapor molar volumes. The calculated phase properties were compared to those of the Peng-Robinson (PR), the simplified-perturbedhard-chain theory (SPHCT) and the original PGR equations. Generally, the performance of the proposed EOS was better than the PR, SPHCT and original PGR equations in predicting the pure fluid properties (%AAD of 1.3, 2.8 and 3.7 for vapor pressure, saturated liquid and vapor densities, respectively).A manuscript we have prepared for publication is attached in lieu of detailed technical information. EXECUTIVE SUMMARYThe Park-Gasem-Robinson (PGR) equation of state (EOS) has been modified to improve its volumetric and equilibrium predictions. Specifically, the attractive term of the PGR equation was modified to...

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“…[8,17,18]. In general, these equations showed better or comparable performance to the PR and SRK equations in calculating fluid phase equilibrium properties of simple mixtures.…”

Section: The Repulsive Termmentioning

confidence: 81%

Phase Behavior of Light Gases in Hydrocarbon and Aqueous Solvents

Gasem¹,

Robinson²

1998

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“…In addition, for the vapour-liquid equilibrium the Maxwell rule is applied. For each experimental point (T=constans) a system of three equations with three unknown EOS parameters was solved: (9) where…”

Section: The Modification Of the Nakamura -Breedveld-prausnitz Equatimentioning

confidence: 99%

“…This is a perturbedhard-sphere equation of state. It was given for gases and their mixtures containing highly polar molecules (such as water, ammonia or sulfur dioxide) and the non-polar or slightly polar molecules (such as hydrogen, argon, nitrogen, carbon monoxide, methane, ethane, ethylene, propane, propylene, hydrogen sulfide or carbon dioxide) 9 . In order to describe the supercritical fluids better, the NBP EOS was successfully modified by Kozio³ 10 .…”

Section: Introductionmentioning

confidence: 99%

Optimization of the quintic equation of the state based model for the calculations of different thermodynamic properties

Kozioł

Wiśniewski

2008

Polish Journal of Chemical Technology

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Different thermodynamic properties (the vapour density, the liquid density and the saturation pressure) were calculated by the model based on the Nakamura-Breedveld-Prausnitz equation of state (NBP EOS). Since the original form of the NBP EOS often generates inaccurate results for liquids, it was modified to describe this phase better. The calculations were realized in the subcritical region. So far, the temperature-dependent NBP EOS parameters have been obtained by special correlations. Their constants were fitted to a lot of experimental data. In this paper the equation of state temperature-dependent parameters were obtained by a new method which was based at piecewise cubic Hermite interpolating polynomials (PCHIPs). In the proposed method some experimental data (called the key ones) were used, thus reducing the experimental effort. Seven substances were chosen for the test calculations. Each of them is common in industry. The calculation results were compared with the experimental data. The new method has made an accurate description of vapour-liquid equilibrium for the considered pure substances over a wide temperature range possible.

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“…In a previous paper6), the perturbed-hard-sphere equation of state proposed by Nakamura et al 7) has been found to be successful to represent both the p-v-T relations and the second and third virial coefficients for water vapor. In the present study, the equation of state is applied to correlate the solubility of water in several compressed nonpolar gases.…”

Section: Introductionmentioning

confidence: 99%