Application of the cubic-plus-association (CPA) equation of state to model the fluid phase behaviour of binary mixtures of water and tetrahydrofuran

Herslund, Peter Jørgensen; Thomsen, Kaj; Abildskov, Jens; Solms, Nicolas von

doi:10.1016/j.fluid.2013.07.036

Cited by 12 publications

(6 citation statements)

References 41 publications

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“…However, this system also exhibits non-ideal behavior in the form of the closed loop phase diagram. Detailed thermodynamic descriptions have been attempted considering the mutualassociation between THF and water as well as self-association between THF molecules [36] but have resulted only in correlation requiring three empirically fitted parameters. Since our attempt is to obtain only some estimates for THF-water interactions rather than represent the global thermodynamic behavior of this binary solvent mixture in liquid and vapor phases, in this paper we have used a constant interaction parameter v TW = 1.5 calculated using solubility parameters [37].…”

Section: Flory Interaction Parametersmentioning

confidence: 99%

“Non-equilibrium” block copolymer micelles with glassy cores: A predictive approach based on theory of equilibrium micelles

Nagarajan

2015

Journal of Colloid and Interface Science

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Section: Flory Interaction Parametersmentioning

confidence: 99%

“Non-equilibrium” block copolymer micelles with glassy cores: A predictive approach based on theory of equilibrium micelles

Nagarajan

2015

Journal of Colloid and Interface Science

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“…Few papers have studied the LLE data correlation of binary systems with closed loop behavior using different equations of state. For example, Herslund et al 28 studied the application of the cubic-plus-association (CPA) equation of state to model the LLE behavior of binary mixtures of water and tetrahydrofuran. Lee 29 used the perturbed sphere hard chain association (PHSC-AS) equation of state for poly(ethylene oxide) aqueous solutions.…”

Section: ■ Introductionmentioning

confidence: 99%

Liquid–Liquid Equilibrium Data Correlation Using NRTL Model for Different Types of Binary Systems: Upper Critical Solution Temperature, Lower Critical Solution Temperature, and Closed Miscibility Loops

Olaya

Carbonell-Hermida

Trives

2020

Ind. Eng. Chem. Res.

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In this work, LLE data at different temperatures have been correlated for 30 binary systems that presented different miscibility behaviour: 15 upper critical solution temperature (UCST), 5 critical solution temperature (LCST) and 10 closed loop LLE region systems. The NRTL model along with an expression frequently used in literature for the temperature dependence in the binary interaction has allowed an acceptable fitting of all the systems. The parameters obtained have been validated by both the inspection of the Gibbs energy of mixing function regarding the fulfilment of the Gibbs common tangent equilibrium condition, and also the stability of the solution to avoid possible metastable equilibrium solutions. The critical solution temperatures have been calculated by extrapolation using the NRTL parameters obtained for all selected binary systems.Moreover, the NRTL parameter values have been analysed using some proposed representations that also include the boundary curve between miscible (L) and partially miscible (LLE) regions. These graphical representations are useful because they show the parameter value requirements to reproduce UCST, LCST or closed loop behaviours.

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“…3.4 -Diagrama de fases para hidrato de metano. A região sombreada compreende a região onde forma-se a fase hidrato(NAKAMURA et al, 2003) HERSLUND, 2013)…”

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“…O método fundamenta-se no uso de cartas que fornecem a pressão de formação de hidratos em função da temperatura e do "peso do gás" (em inglês, gas gravity), que fornece a massa molecular do gás relativa a uma molécula de ar.Além deste método, há ainda o "K-value method", que assume uma solução ideal para os constituintes da fase gasosa para a fase hidrato sólida. Esta abordagem aplica-se com boa precisão para gases leves presentes no gás natural(HERSLUND, 2013). Entretanto, devido a sua base estritamente empírica, estas "cartas" podem fornecer erros significativos para condições que extrapolam os pontos usados na…”

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“…Ele tem sido usado com sucesso para prever o comportamento de muitos hidratos, simples ou complexos, (com mais de um tipo de fugacidade da estrutura hipotética de hidrato vazia, , é definida pelas propriedades para a pressão de vapor da água saturada e seu volume molar. Todas essas propriedades são dependentes da temperatura e pressão(HERSLUND, 2013). respectivamente, na temperatura T e pressão P do sistema; zi, yi e xi representam a fração molar do componente i na fase hidrato, gasosa, e aquosa, respectivamente.…”

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Modelagem do equilíbrio de fases da formação de hidratos utilizando equações volumétricas de estado.

Rocha¹

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Gas hydrates are important for issues that include flow assurance in oil and gas industries, carbon sequestration, natural gas transport, seawater desalinization, and purification of contaminated water. To investigate those fields and applications, temperature and pressure in which hydrates are formed must be determined. This can be done through hydrate formation and/or dissociation experiments, as well as through thermodynamic models, empirical correlations, and computational methods. In this work, the performance of the PC-SAFT in modeling the fluid phase in hydrate phase equilibrium was investigated. Its results were compared to the Peng-Robinson equation of state and to the model proposed by Klauda and Sandler. For the water molecule, different association schemes were considered. For the hydrate phase, the van der Waals and Platteuw (vdWP) equation was used. The effect of additional shells in the estimation of the Langmuir constant was assessed. Finally, equations for water fugacity in hydrate phase, as a function of temperature, were proposed. These equations were intended to be used with the PC-SAFT equation of state, and both linear or quadratic equations were considered. For comparison, when possible the software CSMGem was used to compute the equilibrium conditions. The use of the PC-SAFT EOS, along with the proposed equations, resulted in a better prediction of the equilibrium pressure as a function of temperature.

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Application of the cubic-plus-association (CPA) equation of state to model the fluid phase behaviour of binary mixtures of water and tetrahydrofuran

Cited by 12 publications

References 41 publications

“Non-equilibrium” block copolymer micelles with glassy cores: A predictive approach based on theory of equilibrium micelles

“Non-equilibrium” block copolymer micelles with glassy cores: A predictive approach based on theory of equilibrium micelles

Liquid–Liquid Equilibrium Data Correlation Using NRTL Model for Different Types of Binary Systems: Upper Critical Solution Temperature, Lower Critical Solution Temperature, and Closed Miscibility Loops

Modelagem do equilíbrio de fases da formação de hidratos utilizando equações volumétricas de estado.

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