Effect of guest-dependent reference hydrate vapor pressure in thermodynamic modeling of gas hydrate phase equilibria, with various combinations of equations of state and activity coefficient models

Anil, Jugal N.; Bhawangirkar, Dnyaneshwar R.; Sangwai, Jitendra S.

doi:10.1016/j.fluid.2021.113356

Cited by 8 publications

(3 citation statements)

References 78 publications

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“…A thermodynamic model is presented to predict the three-phase L-H-V equilibria of CH 4 hydrate in pure water and THF solutions that uses an equal fugacity approach as its basis, where the water fugacity ( f w ) in the hydrate phase (H) and the liquid phase (L) are equated: ,,− f w H = f w L …”

Section: Thermodynamic Modelmentioning

confidence: 99%

How Do Varying THF Concentrations Affect the CH₄ Cage Occupancy in CH₄+THF sII Hydrates? A Thermodynamic Approach

Bhawangirkar,

Yin,

Zhang

et al. 2024

Energy Fuels

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Hydrate-based gas storage holds a huge potential to become a promising technology in the future, provided that the storage conditions are moderate enough. Tetrahydrofuran (THF), a widely known promoter, is used in this study to understand its effect on hydrate phase equilibrium conditions and cage occupancies thereafter. Here, we present a fugacity-based thermodynamic model to study the three-phase liquid-hydrate-vapor (L-H-V) equilibria of CH 4 hydrate in pure water (sI hydrate) and in 0.48−5.56 mol % THF solutions (sII hydrate). The model uses the vdW-P theory for the hydrate phase, Peng−Robinson−Stryjek−Vera (PRSV) EOS for the vapor phase, and a modified UNIFAC method for liquid phase calculations. We have introduced a guest−guest interaction parameter for the Langmuir constant estimation. The model also considers the occupancy of CH 4 in large cages of the CH 4 +THF sII hydrate. The AADs of the model predictions from the experimental values for CH 4 hydrate in pure water and THF solutions are 1.52 and 2.75%, respectively. Although THF reduced CH 4 hydrate phase equilibrium pressures drastically in the beginning at 0.48 mol %, no significant changes are observed beyond 3.0 mol % THF concentration. With the increase in THF concentration, the CH 4 occupancy in small and large cages decreased, and the THF occupancy in large cages increased. CH 4 occupancy in sII hydrate large cages is minimal but increases slowly with the temperature. Based on the findings, CH 4 hydrates can be stored at moderate conditions of 298.15 K and 4.71 MPa using an optimal 3.0 mol % THF concentration. The thermodynamic approach developed in this study also provides a significant basis for future hydrate-based gas storage technology.

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Section: Thermodynamic Modelmentioning

confidence: 99%

How Do Varying THF Concentrations Affect the CH₄ Cage Occupancy in CH₄+THF sII Hydrates? A Thermodynamic Approach

Bhawangirkar,

Yin,

Zhang

et al. 2024

Energy Fuels

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“…Davy discovered hydrates of chlorine for the first time in 1810; ever since then, these compounds have been extensively studied for both scientific and practical purposes. , Hammerschmidt noted the presence of hydrates in natural gas pipelines for the first time, which resulted in flow disturbances, loss of production, and affected economic growth; this was the other important reason hydrates drew attention, especially in the oil and gas industry. Gas hydrates have also gained wide attention from researchers across the world when large deposits of methane hydrates have been discovered on the seafloor and in the permafrost region, and they are being considered one of the major sources of fossil fuel in the near future. , There are several other emerging industrial applications of gas hydrates that include the separation of a mixture of gases, methane recovery and carbon dioxide sequestration, , storage and transportation of various gases like methane, , desalination of seawater, and refrigeration …”

Section: Introductionmentioning

confidence: 99%

“…Gas hydrates have also gained wide attention from researchers across the world when large deposits of methane hydrates have been discovered on the seafloor and in the permafrost region, and they are being considered one of the major sources of fossil fuel in the near future. 3,6 There are several other emerging industrial applications of gas hydrates that include the separation of a mixture of gases, 7 methane recovery and carbon dioxide sequestration, 8,9 storage and transportation of various gases like methane, 10,11 desalination of seawater, 12 and refrigeration. 2 To prevent unwanted hydrate formation inside pipelines and to have a smooth operation, an understanding of the phase behavior of these systems is required.…”

Section: Introductionmentioning

confidence: 99%

Thermodynamic Modeling of Methane Hydrate Phase Equilibria in Chloride and Bromide Solutions

Bhawangirkar

2023

Ind. Eng. Chem. Res.

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The formation of hydrates is a major issue in the oil and gas industry. Injection of electrolytes is considered one of the best ways to prevent its formation. A thermodynamic model is developed from the Klauda and Sandler model, PRSV EoS, and Pitzer's correlation to study the phase equilibria of methane hydrate in chloride and bromide electrolyte solutions. The model employs the parameters reported by Pitzer and Mayorga to calculate the Debye−Huckel coefficient and the second and third virial coefficients at 25 °C. The %AAD in predicted equilibrium pressures from experiments is 3.70 when the hydrate formed in NaCl, KCl, MgCl 2 , and CaCl 2 solutions, whereas it is 2.33 in NaBr, KBr, MgBr 2 , CaBr 2 , and ZnBr 2 solutions. The inhibition effect of any electrolyte on methane hydrate formation at 1 wt % is small, slowly increases at 3 wt %, and then pronounces at 5, 10, and 15 wt %. The cage occupancies have been found to increase and the activity of water has been found to decrease with the increase in electrolytes concentration. The freezing point depression of water in the presence of the strongest inhibitor MgCl 2 has been observed to be −12.82 °C, whereas in the presence of the weakest inhibitor ZnBr 2 it is −4.22 °C, both at 15 wt % concentration. Based on the phase equilibrium results and the freezing point depression of water, the order of the methane hydrate inhibition effect among all of the electrolytes studied here is MgCl 2 > NaCl

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Predictions of thermodynamic properties of pure fluids, refrigerants, and binary mixtures using modified Peng-Robinson equation of state

Ghoderao

Narayan²,

Dalvi³

et al. 2022

Korean J. Chem. Eng.

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Effect of guest-dependent reference hydrate vapor pressure in thermodynamic modeling of gas hydrate phase equilibria, with various combinations of equations of state and activity coefficient models

Cited by 8 publications

References 78 publications

How Do Varying THF Concentrations Affect the CH₄ Cage Occupancy in CH₄+THF sII Hydrates? A Thermodynamic Approach

How Do Varying THF Concentrations Affect the CH₄ Cage Occupancy in CH₄+THF sII Hydrates? A Thermodynamic Approach

Thermodynamic Modeling of Methane Hydrate Phase Equilibria in Chloride and Bromide Solutions

Predictions of thermodynamic properties of pure fluids, refrigerants, and binary mixtures using modified Peng-Robinson equation of state

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Effect of guest-dependent reference hydrate vapor pressure in thermodynamic modeling of gas hydrate phase equilibria, with various combinations of equations of state and activity coefficient models

Cited by 8 publications

References 78 publications

How Do Varying THF Concentrations Affect the CH4 Cage Occupancy in CH4+THF sII Hydrates? A Thermodynamic Approach

How Do Varying THF Concentrations Affect the CH4 Cage Occupancy in CH4+THF sII Hydrates? A Thermodynamic Approach

Thermodynamic Modeling of Methane Hydrate Phase Equilibria in Chloride and Bromide Solutions

Predictions of thermodynamic properties of pure fluids, refrigerants, and binary mixtures using modified Peng-Robinson equation of state

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How Do Varying THF Concentrations Affect the CH₄ Cage Occupancy in CH₄+THF sII Hydrates? A Thermodynamic Approach

How Do Varying THF Concentrations Affect the CH₄ Cage Occupancy in CH₄+THF sII Hydrates? A Thermodynamic Approach