Thermal Expansivity of Ionic Clathrate Hydrates Including Gaseous Guest Molecules

Shin, Kyuchul; Lee, Wonhee; Cha, Minjun; Koh, Dong‐Yeun; Choi, Yong Nam; Lee, Heeju; Son, Bae Soon; Lee, Seongsu; Lee, Huen

doi:10.1021/jp110737q

Cited by 12 publications

(11 citation statements)

References 28 publications

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“…The simulation results are close to the experimental values of ionic clathrate hydrates, including gaseous guest molecules in a similar temperature range. 98 Although the trend of thermal expansion with increased temperature is similar to that for the linear expansion of sI hydrates by experimental measurements 21,98 (Fig. 10), the calculated thermal expansion coefficients of 100% sI hydrates at atmospheric pressure in this work are much greater than the experimental values of non-ionic (the conventional gas hydrates) sI hydrates (B70-110 Â 10 À6 K À1 at 180-280 K).…”

Section: Discussionsupporting

confidence: 70%

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Compressibility, thermal expansion coefficient and heat capacity of CH₄ and CO₂ hydrate mixtures using molecular dynamics simulations

Ning

Glavatskiy

et al. 2015

Phys. Chem. Chem. Phys.

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Understanding the thermal and mechanical properties of CH4 and CO2 hydrates is essential for the replacement of CH4 with CO2 in natural hydrate deposits as well as for CO2 sequestration and storage. In this work, we present isothermal compressibility, isobaric thermal expansion coefficient and specific heat capacity of fully occupied single-crystal sI-CH4 hydrates, CO2 hydrates and hydrates of their mixture using molecular dynamics simulations. Eight rigid/nonpolarisable water interaction models and three CH4 and CO2 interaction potentials were selected to examine the atomic interactions in the sI hydrate structure. The TIP4P/2005 water model combined with the DACNIS united-atom CH4 potential and TraPPE CO2 rigid potential were found to be suitable molecular interaction models. Using these molecular models, the results indicate that both the lattice parameters and the compressibility of the sI hydrates agree with those from experimental measurements. The calculated bulk modulus for any mixture ratio of CH4 and CO2 hydrates varies between 8.5 GPa and 10.4 GPa at 271.15 K between 10 and 100 MPa. The calculated thermal expansion and specific heat capacities of CH4 hydrates are also comparable with experimental values above approximately 260 K. The compressibility and expansion coefficient of guest gas mixture hydrates increase with an increasing ratio of CO2-to-CH4, while the bulk modulus and specific heat capacity exhibit the opposite trend. The presented results for the specific heat capacities of 2220-2699.0 J kg(-1) K(-1) for any mixture ratio of CH4 and CO2 hydrates are the first reported so far. These computational results provide a useful database for practical natural gas recovery from CH4 hydrates in deep oceans where CO2 is considered to replace CH4, as well as for phase equilibrium and mechanical stability of gas hydrate-bearing sediments. The computational schemes also provide an appropriate balance between computational accuracy and cost for predicting mechanical and thermal properties of gas hydrates in the high temperature range (≥260 K), and the schemes may be useful for the study of other complex hydrate systems.

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Section: Discussionsupporting

confidence: 70%

“…21 The values are relatively close to those of ionic sI hydrates including gaseous guest molecules (B110-244 Â 10 À6 K À1 at 180-280 K). 98 In the same way, the specific heat capacities calculated by our simulations also exhibit an obvious discrepancy with the experimental values below 260 K (Fig. 12).…”

Section: Discussionmentioning

confidence: 51%

Compressibility, thermal expansion coefficient and heat capacity of CH₄ and CO₂ hydrate mixtures using molecular dynamics simulations

Ning

Glavatskiy

et al. 2015

Phys. Chem. Chem. Phys.

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“…We also note that inherent molecular details of encaged guests such as ionic/nonionic and hydrophilic/hydrophobic guests greatly influence the cage dynamics. [2][3][4][5][6] Recently, hydrogen has received a great deal of attention in the hydrate community owing to its high potential for use in energy-related and many other issues. [7,8] Numerous studies concerning hydrogen storage using clathrate hydrates have been reported with much efforts aimed at increasing storage capacity, introducing unusual tuning effects by changes in concentration and pressure.…”

Section: Introductionmentioning

confidence: 99%

Abnormal Thermal Expansion of Clathrate Hydrates Induced by Asymmetric Guest Molecules

Cha¹,

Youn²,

Kwon³

et al. 2011

Chemistry An Asian Journal

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We investigated for the first time the abnormal thermal expansion induced by an asymmetric guest structure using high-resolution neutron powder diffraction. Three dihydrogen molecules (H(2), D(2), and HD) were tested to explore the guest dynamics and thermal behavior of hydrogen-doped clathrate hydrates. We confirmed the restricted spatial distribution and doughnut-like motion of the HD guest in the center of anisotropic sII-S (sII-S=small cages of structure II hydrates). However, we failed to observe a mass-dependent relationship when comparing D(2) with HD. The use of asymmetric guest molecules can significantly contribute to tuning the cage dimension and thus can improve the stable inclusion of small gaseous molecules in confined cages.

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“…16−18 The unique ionic guest−host interactions caused differences in the thermal expansivities of nonionic and ionic clathrate hydrates, and the γ-irradiated hydrates showed a smaller thermal expansivity and a larger dependence on secondary guest molecules. 19,20 While the thermal expansion behavior is important fundamental research, it also might be exploited in applications such as enhancing gas storage capacity by tuning the lattice dimensions. 21,22 Despite the importance and applicability of the structural effect of large guest molecules, which might have a significant impact on guest−host interactions, few studies have been conducted on this subject.…”

Section: ■ Introductionmentioning

confidence: 99%

Effects of Large Guest Molecular Structure on Thermal Expansion Behaviors in Binary (C₄H₈O + CH₄) Clathrate Hydrates

et al. 2019

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Investigating the thermal expansion of clathrate hydrates is essential for understanding their complex physicochemical properties. Although there have been various discussions on the thermal expansion, few studies have investigated the structural effect of each guest molecule. To compare the lattice expansion behaviors with cyclic and linear large guest molecules, cyclobutanol and butyraldehyde, having the same formula of C4H8O, were used as new sII hydrate formers with a help gas of CH4. In Raman spectra of the bonding characteristics, the peaks of the C–H stretching mode, O–H stretching mode, and O:H stretching phonon showed unique shift behaviors as the temperature rises. A crystallographic analysis using high-resolution powder diffraction showed that the (cyclobutanol + CH4) hydrate undergoes smaller lattice expansion than the (butyraldehyde + CH4) hydrate under thermal stimulations, and the phase equilibria showed that the cyclobutanol case involves milder formation conditions than the butyraldehyde case. These structural effects could be based on the different guest–host interactions, and molecular dynamics simulation results also show that the different thermal expansivity or molecular motion of the large guest in a hydrate cage causes these unique interactions. The results of this study provide insight into distinctive guest–host interactions depending on the guest structure and their effects on the hydrate lattice.

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Thermal Expansivity of Ionic Clathrate Hydrates Including Gaseous Guest Molecules

Cited by 12 publications

References 28 publications

Compressibility, thermal expansion coefficient and heat capacity of CH₄ and CO₂ hydrate mixtures using molecular dynamics simulations

Compressibility, thermal expansion coefficient and heat capacity of CH₄ and CO₂ hydrate mixtures using molecular dynamics simulations

Abnormal Thermal Expansion of Clathrate Hydrates Induced by Asymmetric Guest Molecules

Effects of Large Guest Molecular Structure on Thermal Expansion Behaviors in Binary (C₄H₈O + CH₄) Clathrate Hydrates

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Thermal Expansivity of Ionic Clathrate Hydrates Including Gaseous Guest Molecules

Cited by 12 publications

References 28 publications

Compressibility, thermal expansion coefficient and heat capacity of CH4 and CO2 hydrate mixtures using molecular dynamics simulations

Compressibility, thermal expansion coefficient and heat capacity of CH4 and CO2 hydrate mixtures using molecular dynamics simulations

Abnormal Thermal Expansion of Clathrate Hydrates Induced by Asymmetric Guest Molecules

Effects of Large Guest Molecular Structure on Thermal Expansion Behaviors in Binary (C4H8O + CH4) Clathrate Hydrates

Contact Info

Product

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Compressibility, thermal expansion coefficient and heat capacity of CH₄ and CO₂ hydrate mixtures using molecular dynamics simulations

Compressibility, thermal expansion coefficient and heat capacity of CH₄ and CO₂ hydrate mixtures using molecular dynamics simulations

Effects of Large Guest Molecular Structure on Thermal Expansion Behaviors in Binary (C₄H₈O + CH₄) Clathrate Hydrates