Use of a non additive GC-PPC-SAFT equation of state to model hydrogen solubility in oxygenated organic compounds

Trinh, Thi-Kim-Hoang; Passarello, Jean-Philippe; Hemptinne, Jean-Charles de; Lugo, Rafael

doi:10.1016/j.fluid.2016.08.003

Cited by 10 publications

(2 citation statements)

References 67 publications

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“…In the ePPC-SAFT model, − ,− the residual Helmholtz free energy is given as A res = A hc + A disp + A assoc + A polar + A NAHS + A MSA + A Born where the superscript hc denotes hard-chain, disp denotes dispersion, assoc denotes association, polar denotes multipolar as presented by refs − , NAHS denotes the nonadditive hard sphere as presented by ref . The NAHS term corrects for the combining rule of the diameters and is used in this work only for water–methanol, for which the parameter was obtained in previous work .…”

Section: Methodsmentioning

confidence: 99%

Ion Pairing in ePPC-SAFT for Aqueous and Mixed-Solvent Alkali Halide Solutions

Yang,

Raeispour Shirazi,

Roa Pinto

et al. 2024

Ind. Eng. Chem. Res.

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Short-range ion−solvent and ion−ion interactions need to be taken into account in molecule-based electrolyte equations of state. The ePPC-SAFT (electrolyte polar perturbed chain statistical associating fluid theory) model consists of hard chain, dispersion, association, multipolar, nonadditive hard sphere, mean spherical approximation, and Born contributions. Using Wertheim's first-order thermodynamic perturbation theory for associating fluids to account for short-range cation−anion interactions offers significant advantages over models that use ion−ion dispersion interactions only. However, the ionic association framework assigns the same number of sites for ion−solvent and cation−anion interactions, assuming the formation of ion clusters. This work proposes a new association framework in which ion−ion and ion−solvent association sites are labeled, restricting the ion−ion association site number to one per ion to prevent the formation of larger ion clusters. This approach improves modeling accuracy compared to the original model, in which ion clustering was considered, without increasing the number of adjustable parameters. Furthermore, this work proposes a generalized Bjerrum theory with one adjustable parameter in the association strength function, as in Wertheim's theory, and proposes an analytical approximation for the Bjerrum integral to speed up calculations. This work uses Wertheim's theory for short-range ion−solvent interactions and compares Wertheim's theory and Bjerrum's theory for short-range ion−ion interactions, i.e., ion pairing. The new association framework with Wertheim's theory for both short-range ion−ion and ion−solvent associations is demonstrated to be significantly more accurate compared to Bjerrum's theory and slightly more accurate than the previous best practice. The model extends to mixed-solvent electrolyte solutions. Furthermore, the contributions of Helmholtz free energy terms and number of bonds of the ions are analyzed.

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Section: Methodsmentioning

confidence: 99%

Ion Pairing in ePPC-SAFT for Aqueous and Mixed-Solvent Alkali Halide Solutions

Yang,

Raeispour Shirazi,

Roa Pinto

et al. 2024

Ind. Eng. Chem. Res.

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“…Thus, in contrast to other systems, the binary interaction parameter between N 2 and ions is directly fitted to match "PTx" experimental data at elevated pressure, covering a wider range of temperature (303 to 398 K) and salinities (up to 5.5 mol/kg) [55,56]. For hydrogen, nitrogen, and oxygen, the experimental compressibility factors are used to adjust the dispersion energy and segment diameter of each of these light gas, while segment numbers are taken from previous studies [92,93]. Table 4 gives the optimized parameters, and Figure 2 compares calculated values and reference data.…”

Section: Light Gas + Brine Systemsmentioning

confidence: 99%

Hydrogen and air storage in salt caverns: a thermodynamic model for phase equilibrium calculations

Kiemde

Ferrando²,

Hemptinne³

et al. 2023

STET

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When storing gas in a salt cavern, it occupies most of the excavated volume, but the lower part of the cavern inevitably contains residual brine, in contact with the gas. The design of hydrogen and compressed air storage in salt caverns requires to have a thermodynamic model able to accurately predict both phase properties such as densities, and phase equilibrium (gas solubility and water content of the vapour phase). This work proposes a parameterization of the e-PPC-SAFT equation of state in this context. Experimental data of pure components and mixtures of light gas + pure water and light gas + salted water are reviewed and used to fit pure component parameters for hydrogen, nitrogen, oxygen, and the brine, and binary interaction parameters between H2, O2, N2 + water and H2, O2, N2 + ions (Na+ and Cl−), for temperature ranging from 273 to 473 K and salinities up to NaCl saturation (6 mol/kg). The model developed delivers good accuracy in reproducing data: the average deviation between experiments and calculated data is between 3% and 9% for gas solubility in saturated brine. More interestingly, the model has been validated on its capability to predict data not included in the parameterization database, including the composition of the vapor phase, and its extension to a mixture, such as air. Finally, it has been used in a case study of Compressed Air Energy Storage (CAES) to evaluate the water content of the gas produced during injection-withdrawing cycles.

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