Approach to Improve Speed of Sound Calculation within PC-SAFT Framework

Liang, Xiaodong; Maribo-Mogensen, Bjørn; Thomsen, Kaj; Yan, Wei; Kontogeorgis, Georgios M.

doi:10.1021/ie3018127

Cited by 61 publications

(91 citation statements)

References 62 publications

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“…significantly better with the SAFT-type models compared to the CPA-based models. This is unsurprising, as it is by now well established that SAFT can predict the trend of the speed of sound much better than CPA-based models [1,59]. Critical region.…”

Section: Critical Pointsmentioning

confidence: 99%

Modeling derivative properties and binary mixtures with CO2 using the CPA and the quadrupolar CPA equations of state

Bjørner

Kontogeorgis

2016

Fluid Phase Equilibria

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The cubic plus association (CPA) equation of state (EoS) is extended to include quadrupolar interactions. The quadrupolar term is based on a modification of the perturbation terms by Larsen et al. (Mol. Phys. 1977, 33, 4, 987) for a hard sphere fluid with a symmetric point quadrupole moment. The new quadrupolar CPA (qCPA) can be used without introducing any additional pure compound parameters. Alternatively a single additional adjustable parameter can be employed.To evaluate qCPA several pure compound properties are predicted. The model is furthermore evaluated for its ability to predict and correlate binary vapor-liquid equilibria (VLE) and liquid-liquid equilibria (LLE) of mixtures containing CO 2 and hydrocarbons, water, alcohols, or selected quadrupolar compounds.The results indicate that most pure compound property predictions are satisfactory but similar to other CPA approaches. When binary mixtures are con- qCPA can accurately correlate both the phase behaviour of CO 2 + hydrocarbon mixtures as well as mixtures of CO 2 + a self-associating compound.

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Section: Critical Pointsmentioning

confidence: 99%

Modeling derivative properties and binary mixtures with CO2 using the CPA and the quadrupolar CPA equations of state

Bjørner

Kontogeorgis

2016

Fluid Phase Equilibria

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“…The parameters of methanol and ethanol are from 55,60 for which speed of sound were used in the parameter estimation. The parameters of 1-propanol and 1-pentanol are from Grenner et al, 61 but the "optimized" set is used for 1-propanol, whereas the "generalized" set is used for 1-pentanol.…”

Section: Industrial and Engineering Chemistry Researchmentioning

confidence: 99%

Modeling Water Containing Systems with the Simplified PC-SAFT and CPA Equations of State

Liang

Tsivintzelis

Kontogeorgis

2014

Ind. Eng. Chem. Res.

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111

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Numerous studies have been presented for modeling of water containing systems with the perturbed-chain statistical associating fluid theory (PC-SAFT) equation of state (EOS), and more than 20 water parameter sets have been published with emphasis on different applications. In this work, eight of these sets and new estimated parameters with different association schemes are systematically compared on describing properties of pure water, the liquid−liquid equilibria (LLE) of water with hydrocarbons, and the vapor−liquid (VLE) and/or vapor−liquid−liquid equilibria (VLLE) of water with 1-alcohols. An interactive procedure is further proposed for including the LLE of water with hydrocarbons into the pure fluid parameter estimation. The results show that it is possible for PC-SAFT to give an accurate description of the LLE of water and hydrocarbons while retaining satisfactory accuracy for both vapor pressure and saturated liquid density of water. For the aforementioned aqueous systems, the PC-SAFT correlations using the newly developed parameters are compared with the corresponding correlations of the cubic plus association EOS. The two models show comparable results for phase equilibria, and both of them fail to describe second-order derivative properties of water, i.e., residual isochoric heat capacity and speed of sound. The ability of the models to predict the monomer (free site) fractions of saturated pure water is investigated and discussed from various aspects. The results suggest that more experimental or theoretical studies are needed.

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“…These derivative properties are of interest from a practical perspective (e.g., the use of the Joule-Thomson inversion curve in the Linde technique as a standard industrial process), and a precise description of such properties, for which the performance of traditional cubic EoSs has been shown to be relatively poor, [75][76][77][78] is highly challenging from a theoretical perspective. 75 An accurate representation of derivative properties is a stringent test even with a more sophisticated thermodynamic treatment such as SAFT.…”

Section: Introductionmentioning

confidence: 99%

“…84 A number of studies have been carried out with the aim of improving the description of the derivative properties. 76,77,[85][86][87] However, the simultaneous representation of fluid-phase behavior and derivative properties is found to come at a cost: Maghari et al 86,87 have employed an empirical temperature dependence of the dispersion energy by means of compound-specific constants, while Kontogeorgis and co-workers 77 re-correlated the universal constants of the PC-SAFT EoS to include derivative property data.…”

Section: Introductionmentioning

confidence: 99%

Group contribution methodology based on the statistical associating fluid theory for heteronuclear molecules formed from Mie segments

Papaioannou

Lafitte

Avendaño

et al. 2014

The Journal of Chemical Physics

236

424

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A group contribution method for associating chain molecules based on the statistical associating fluid theory (SAFT-) The Journal of Chemical Physics 127, 234903 (2007) (2013)] is formulated within the framework of a group contribution approach (SAFT-γ Mie). Molecules are represented as comprising distinct functional (chemical) groups based on a fused heteronuclear molecular model, where the interactions between segments are described with the Mie (generalized Lennard-Jonesium) potential of variable attractive and repulsive range. A key feature of the new theory is the accurate description of the monomeric group-group interactions by application of a high-temperature perturbation expansion up to third order. The capabilities of the SAFT-γ Mie approach are exemplified by studying the thermodynamic properties of two chemical families, the n-alkanes and the n-alkyl esters, by developing parameters for the methyl, methylene, and carboxylate functional groups (CH 3 , CH 2 , and COO). The approach is shown to describe accurately the fluid-phase behavior of the compounds considered with absolute average deviations of 1.20% and 0.42% for the vapor pressure and saturated liquid density, respectively, which represents a clear improvement over other existing SAFT-based group contribution approaches. The use of Mie potentials to describe the group-group interaction is shown to allow accurate simultaneous descriptions of the fluid-phase behavior and second-order thermodynamic derivative properties of the pure fluids based on a single set of group parameters. Furthermore, the application of the perturbation expansion to third order for the description of the reference monomeric fluid improves the predictions of the theory for the fluid-phase behavior of pure components in the near-critical region. The predictive capabilities of the approach stem from its formulation within a group-contribution formalism: predictions of the fluid-phase behavior and thermodynamic derivative properties of compounds not included in the development of group parameters are demonstrated. The performance of the theory is also critically assessed with predictions of the fluid-phase behavior (vapor-liquid and liquid-liquid equilibria) and excess thermodynamic properties of a variety of binary mixtures, including polymer solutions, where very good agreement with the experimental data is seen, without the need for adjustable mixture parameters.

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Approach to Improve Speed of Sound Calculation within PC-SAFT Framework

Cited by 61 publications

References 62 publications

Modeling derivative properties and binary mixtures with CO2 using the CPA and the quadrupolar CPA equations of state

Modeling derivative properties and binary mixtures with CO2 using the CPA and the quadrupolar CPA equations of state

Modeling Water Containing Systems with the Simplified PC-SAFT and CPA Equations of State

Group contribution methodology based on the statistical associating fluid theory for heteronuclear molecules formed from Mie segments

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