Thermodynamic Models for Industrial Applications

Kontogeorgis, Georgios M.; Folas, Georgios K.

doi:10.1002/9780470747537

Cited by 398 publications

(543 citation statements)

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“…Of particular relevance to our current work is the seminal theory of Wertheim [37][38][39][40] for associating fluids which is based on a highly-convergent cluster expansion in terms of both the density of the monomer (un-associated) species and the overall density. Wertheim put forward an elegant formalism (for molecules modelled as hard cores with directional, off-centre bonding sites) cast both as an integralequation theory and as a first-order thermodynamic perturbation theory (TPT1); the latter form is particularly convenient for the development of algebraic EOSs for associating fluids [41,42] and is now firmly at the heart of the SAFT family of EOSs [1,2,[43][44][45][46][47][48].…”

Section: Introductionmentioning

confidence: 99%

The A in SAFT: developing the contribution of association to the Helmholtz free energy within a Wertheim TPT1 treatment of generic Mie fluids

et al. 2015

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(2015) The A in SAFT: developing the contribution of association to the Helmholtz free energy within a Wertheim TPT1 treatment of generic Mie fluids, Molecular Physics, 113:9-10, 948-984, DOI: 10.1080/00268976.2015 An accurate representation of molecular association is a vital ingredient of advanced equations of state (EOSs), providing a description of thermodynamic properties of complex fluids where hydrogen bonding plays an important role. The combination of the first-order thermodynamic perturbation theory (TPT1) of Wertheim for associating systems with an accurate description of the structural and thermodynamic properties of the monomer fluid forms the basis of the statistical associating fluid theory (SAFT) family of EOSs. The contribution of association to the free energy in SAFT and related EOSs is very sensitive to the nature of intermolecular potential used to describe the monomers and, crucially, to the accuracy of the representation of the thermodynamic and structural properties. Here we develop an accurate description of the association contribution for use within the recently developed SAFT-VR Mie framework for chain molecules formed from segments interacting through a Mie potential [T. Lafitte, A. Apostolakou, C. Avendaño, A, Galindo, C. S. Adjiman, E. A. Müller, and G. Jackson, J. Chem. Phys. 139, 154504 (2013)]. As the Mie interaction represents a soft-core potential model, a method similar to that adopted for the Lennard-Jones potential [E. A. Müller and K. E. Gubbins, Ind. Eng. Chem. Res. 34, 3662 (1995)] is employed to describe the association contribution to the Helmholtz free energy. The radial distribution function (RDF) of the Mie fluid (which is required for the evaluation of the integral at the heart of the association term) is determined for a broad range of thermodynamic conditions (temperatures and densities) using the reference hyper-netted chain (RHNC) integral-equation theory. The numerical data for the association kernel of Mie fluids with different association geometries are then correlated for a range of thermodynamic states to obtain a general expression for the association contribution which can be applied for varying values of the Mie repulsive exponent. The resulting SAFT-VR Mie EOS allows for a much improved description of the vapour-liquid equilibria and single-phase properties of associating fluids such as water, methanol, ammonia, hydrogen sulphide, and their mixtures. A comparison is also made between the theoretical predictions of the degree of association for water and the extent of hydrogen bonding obtained from molecular simulations of the SPC/E and TIP4P/2005 atomistic models.

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Section: Introductionmentioning

confidence: 99%

The A in SAFT: developing the contribution of association to the Helmholtz free energy within a Wertheim TPT1 treatment of generic Mie fluids

et al. 2015

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“…The literature on the development and use of the SAFT EOS is too extensive to be enumerated here; the reader is directed to excellent reviews which provide a comprehensive description of the theory and its successful application to the phase equilibria of complex fluids ranging from small associating compounds to multi-component systems including polymers, surfactants, micelles, liquid crystals, asphaltenes, and electrolyte solutions. [49][50][51][52][53][54][55] The main feature of the SAFT approach is that the thermodynamic and structural properties of a fluid of associating chain molecules are described in terms of those of a corresponding monomer (reference) system comprising the segments that form the molecule. One must first define explicitly the intermolecular potential of the reference fluid, typically an isotropic potential, and then evaluate the system's free energy and structure via the radial distribution function (RDF).…”

Section: Equations Of State For Complex Fluidsmentioning

confidence: 99%

Accurate statistical associating fluid theory for chain molecules formed from Mie segments

Lafitte

Apostolakou

Avendaño

et al. 2013

The Journal of Chemical Physics

437

735

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“…This scale employs a convention of a hypothetical ideal solution at unit molality such that ࢣ i m i → 0 ⇒ γ i, m → 1. The conversion between the rational asymmetric scale and the molal-based scale follows as [58] …”

Section: Thermodynamic Properties Of Electrolyte Solutionsmentioning

confidence: 99%

Development of intermolecular potential models for electrolyte solutions using an electrolyte SAFT-VR Mie equation of state

et al. 2016

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We present a theoretical framework and parameterisation of intermolecular potentials for aqueous electrolyte solutions using the statistical associating fluid theory based on the Mie interaction potential (SAFT-VR Mie), coupled with the primitive, non-restricted mean-spherical approximation (MSA) for electrolytes. In common with other SAFT approaches, water is modelled as a spherical molecule with four off-centre association sites to represent the hydrogen-bonding interactions; the repulsive and dispersive interactions between the molecular cores are represented with a potential of the Mie (generalised Lennard-Jones) form. The ionic species are modelled as fully dissociated, and each ion is treated as spherical: Coulombic ion-ion interactions are included at the centre of a Mie core; the ion-water interactions are also modelled with a Mie potential without an explicit treatment of iondipole interaction. A Born contribution to the Helmholtz free energy of the system is included to account for the process of charging the ions in the aqueous dielectric medium. The parameterisation of the ion potential models is simplified by representing the ion-ion dispersive interaction energies with a modified version of the London theory for the unlike attractions. By combining the Shannon estimates of the size of the ionic species with the Born cavity size reported by Rashin and Honig, the parameterisation of the model is reduced to the determination of a single ion-solvent attractive interaction parameter. The resulting SAFT-VRE Mie parameter sets allow one to accurately reproduce the densities, vapour pressures, and osmotic coefficients for a broad variety of aqueous electrolyte solutions; the activity coefficients of the ions, which are not used in the parameterisation of the models, are also found to be in good agreement with the experimental data. The models are shown to be reliable beyond the molality range considered during parameter estimation. The inclusion of the Born free-energy contribution, together with appropriate estimates for the size of the ionic cavity, allows for accurate predictions of the Gibbs free energy of solvation of the ionic species considered. The solubility limits are also predicted for a number of salts; in cases where reliable reference data are available the predictions are in good agreement with experiment.

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Thermodynamic Models for Industrial Applications

Cited by 398 publications

References 0 publications

The A in SAFT: developing the contribution of association to the Helmholtz free energy within a Wertheim TPT1 treatment of generic Mie fluids

The A in SAFT: developing the contribution of association to the Helmholtz free energy within a Wertheim TPT1 treatment of generic Mie fluids

Accurate statistical associating fluid theory for chain molecules formed from Mie segments

Development of intermolecular potential models for electrolyte solutions using an electrolyte SAFT-VR Mie equation of state

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