Phase equilibrium measurements and modelling of mixed cyclopentane and carbon dioxide hydrates in presence of salts

Babakhani, Saheb Maghsoodloo; Ho-Van, Son; Bouillot, Baptiste; Douzet, Jérôme; Herri, Jean‐Michel

doi:10.1016/j.ces.2019.115442

Cited by 12 publications

(9 citation statements)

References 58 publications

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“…The total sum of such contributions is approximated by using the pair potential function. These contributions are extensively used in the hydrate phase equilibrium studies and to estimate the Langmuir adsorption constant of the host cavity 8,14–17,23 . The summed interactions over the water molecules of the host cavity is,

W ((), r) goodbreak= 2 italicze ([], \frac{σ^{12}}{R_{cell}^{11} r} ((), δ^{10} goodbreak+ \frac{a}{R} δ^{11}) goodbreak- \frac{σ^{6}}{R_{cell}^{5} r} ((), δ^{4} goodbreak+ \frac{a}{R} δ^{5}))

where,

z

and

R_{cell}

are the coordination number and radius of the host cavity, respectively.…”

Section: Thermodynamic Modelingmentioning

confidence: 99%

“…The classical description of bulk phase 53 appropriately considers the influence of temperature, pressure, and composition on the bulk to hydrate transition. However, the hydrate phase is assumed to be stabilized only by interactions with the host cavity 3,8,14–17,23 . As identified through the NCI analysis, these guest–host interactions partake the overall lattice stability, and additional interactions need to be considered to inclusively describe the hydrate phase.…”

Section: Thermodynamic Modelingmentioning

confidence: 99%

“…To accurately represent the guest saturated bulk phase (a prerequisite to hydrate crystal inception), the equation of state models are widely used to estimate the dynamic vapor liquid equilibrium (VLE) 12,13 . Employing the vdWP model, these VLE approaches along with several others 10,14–17 usually regress the potential function parameters to the experimental data of mixed guest hydrates. This excessive use of pair potential function as a regression model for the HLV phase equilibrium data results in multiple sets of probable parameters, all representing the same guest‐host interaction.…”

Section: Introductionmentioning

confidence: 99%

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Formulating noncovalent interactions to predict structural transition in mixed guest hydrates

Dongre

Jana

2022

AIChE Journal

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This work aims at formulating the noncovalent interactions of the mixed guest hydrate lattices of sI and sII structures. The reduced density plots obtained at the B3LYP level with 6‐31G(d) split valence set unveil the crucial contributions of hydrogen bonding, dispersion, van der Waals interaction, and steric effects toward lattice stability. These contributions are rather unreported in the hydrate phase equilibrium modeling. With this research gap, we attempt to formulate the natural regularity in the nonstoichiometric hydrates by the spherical harmonics shape descriptor. The van der Waals and hydrogen‐bond interactions are described with Kihara spherical cell potential and ab initio based calculations, respectively. Further, the ionization potential and polarizability of the guest molecule describe the dispersion interactions. Combining these contributions, we introduce a theoretical framework for the phase equilibrium modeling of mixed guest hydrates. This novel formulation offers various appealing advantages as: significantly reduced parametric structure, standardization of the parameter value for host–host pair, and generalized model framework. Despite of making the proposed theory so simple, it consistently outperforms the existing latest models, which employ various state equations, ab initio based calculations and CSMGem, for a wide variety of systems (total 26 systems tested) with reference to the experimental data.

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W ((), r) goodbreak= 2 italicze ([], \frac{σ^{12}}{R_{cell}^{11} r} ((), δ^{10} goodbreak+ \frac{a}{R} δ^{11}) goodbreak- \frac{σ^{6}}{R_{cell}^{5} r} ((), δ^{4} goodbreak+ \frac{a}{R} δ^{5}))

where,

z

and

R_{cell}

are the coordination number and radius of the host cavity, respectively.…”

Section: Thermodynamic Modelingmentioning

confidence: 99%

Section: Thermodynamic Modelingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Formulating noncovalent interactions to predict structural transition in mixed guest hydrates

Dongre

Jana

2022

AIChE Journal

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“…Number of publications on different hydrate formers from 2019 to 2020 − based on search results from Google Scholar using keywords “refrigerant” + “hydrate” on 23 February 2021.…”

Section: Methodsmentioning

confidence: 99%

Conceptual Design of a Sustainable Hybrid Desalination Process Using Liquefied Natural Gas Cold Energy

Lee

Lim

et al. 2021

ACS Sustainable Chem. Eng.

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To counter growing shortages in water supply and the energy crisis, a sustainable hybrid desalination process using liquefied natural gas (LNG) cold energy is proposed in this study. The newly proposed dual-expander organic Rankine cycle-hydrate-based desalination (dual-expander ORC-HBD) process with a reverse osmosis (RO) system consists of two expanders to utilize LNG cold energy and pressure energy simultaneously and can cogenerate electricity and pure water. To analyze the feasibility of the proposed dual-expander ORC-HBD process, computational modeling was performed using liquid-phase and gas-phase hydrate formers (propane, R125A, R141B, and cyclopentane). Thereafter, optimization, energy, and sensitivity analyses were also conducted. The dual-expander ORC-HBD process using propane resulted in a negative product cost to yield a profit of up to 0.521 $/ton of pure water while producing 82.5 tons/h of pure water and electricity (25.4 kWh/ton of pure water). These profits could be further increased to 3.095 $/ton of pure water with free external heat. These values are superior to many RO technologies in terms of energy, exergy, and economics. Therefore, the dual-expander ORC-HBD process with the RO system has a strong potential for resolving the water shortage and electricity generation crises simultaneously.

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“…The gradual temperature increase was suggested to be induced by the heat release of hydrate formation. Since the equilibrium pressure of pure CO 2 hydrate in 3.5 wt% NaCl solution was over 3.5 MPa and CP hydrate could form without CO 2 at 281 K, the hydrates formed in the initial stage of hydrate growth should be the mixed CP-CO 2 hydrates which contained only a small fraction of CO 2 molecules [29][30][31][32].…”

Section: Kinetic Featuresmentioning

confidence: 99%

Formation Kinetics of the Mixed Cyclopentane—Carbon Dioxide Hydrates in Aqueous Sodium Chloride Solutions

et al. 2020

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Hydrate formation from cyclopentane (CP) and carbon dioxide was measured at 281 K by powder X-ray diffraction (PXRD) and macroscopic methods. The effect of initial pressure and CP mass fraction in liquid phase was analyzed. The results showed that hydrate formation was assumed to start with the nucleation of the mixed CP-CO2 hydrate with small fraction of CO2 followed by a large continuous CO2 adsorption. Initial pressure was found to have a positive correlation with the total CO2 consumptions when the initial pressure was below 2.5 MPa. However, the total CO2 consumptions dropped by over a half as the initial pressure was 3.0 MPa. PXRD revealed that all the hydrate samples formed at different initial pressures were structure II. The CO2 consumptions were assumed to be inhibited by the competitive occupation of 51264 cages between CP and CO2 molecules when the initial pressure was above 2.5 MPa. The CO2 consumptions were also found to be reduced as the CP mass fraction was above 0.25. An excess of CP molecules was not assumed to strengthen the formation of the mixed CP-CO2 hydrates at the initial stage, but increased the thickness of liquid CP film at aqueous brine and hydrate particles, which increased the diffusion resistance of CO2 molecules. Therefore, the suitable initial pressure and the CP mass fraction for the mixed CP-CO2 hydrate formation should be around 2.5 MPa and 0.2, respectively.

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Phase equilibrium measurements and modelling of mixed cyclopentane and carbon dioxide hydrates in presence of salts

Cited by 12 publications

References 58 publications

Formulating noncovalent interactions to predict structural transition in mixed guest hydrates

Formulating noncovalent interactions to predict structural transition in mixed guest hydrates

Conceptual Design of a Sustainable Hybrid Desalination Process Using Liquefied Natural Gas Cold Energy

Formation Kinetics of the Mixed Cyclopentane—Carbon Dioxide Hydrates in Aqueous Sodium Chloride Solutions

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