Multiscale Modeling and Simulation of Water and Methane Hydrate Crystal Interface

Mirzaeifard, Sina; Servio, Phillip; Rey, Alejandro D.

doi:10.1021/acs.cgd.9b00578

Cited by 20 publications

(33 citation statements)

References 89 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In this work, The united-atom optimized potentials for liquid simulations (OPLS-UA) force field is used to describe CH 4 molecules. 10,49 CO 2 molecules are described by the full flexible potential model based on the EPM2 model. 7,26,37,43 Because the melting point and density (272.2 K and 0.985 g/cm 3 ) of the TIP4P/ Ice model are closer to the experimental values (273.15 K and 0.999 g/cm 3 ) than the other three popular fully atomistic rigid water models (SPC/E, TIP4P, and TIP4P/Ew), the TIP4P/Ice model is applied to describe water molecules.…”

Section: Models and Methodologymentioning

confidence: 99%

“…54−56 The long-ranged electrostatic interactions are calculated in the particle−particle− particle−mesh (PPPM) method. 2,5,10,37,43,50 Periodic boundary conditions are applied in all directions. The cutoff distance is set to be 12 Å.…”

Section: Models and Methodologymentioning

confidence: 99%

“…Hydrates are ice-like crystalline substances in which polyhedral cages are formed through hydrogen bonds (HBs), while guest molecules are trapped inside the water cavities. − Hydrates occur extensively in deep-sea continental shelves and permafrost regions. , It is conservatively estimated that the global natural gas hydrate reserves exceed 2.1 × 10 16 m 3 , which are more than twice that of traditional fossil energy . In addition, gas-hydrate-based technologies have a variety of potential applications, including gas separation, solution extraction, seawater desalination, energy storage, and cryopreservation. ,− However, CH 4 , which is the main component of natural gas, as a stronger greenhouse gas than CO 2 , can induce ocean acidification and tsunami and cause local geological or climatic environment deterioration once large-scale leakage occurs during the exploitation process. ,− These indicate that gas hydrates have a profound impact on marine ecology, seabed stability, safety of oil production, and trapped-gas recovery. ,− Driven by these issues of practical significance, many efforts have been made in the past decades to study the stability conditions and physical and chemical properties of hydrates . Unfortunately, the complex occurrence mechanism and heterogeneity of the gas hydrate greatly limit the study of its properties. ,, The stability, especially the mechanical stability, remains a big challenge in the process of natural gas hydrate recovery. ,, …”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Mechanical Properties of a Structure I CO₂–CH₄ Heteroclathrate Hydrate: Insight from Molecular Dynamics Simulations

Meng

Liu

et al. 2021

Energy Fuels

View full text Add to dashboard Cite

Mechanical stability of the CO 2 −CH 4 heteroclathrate hydrate dominates the geomechanical stability of natural gas hydrate deposits when CO 2 replaces CH 4 from gas hydrate reservoirs. Here, molecular dynamics simulations were employed to investigate the strain-induced fracture behaviors of the CO 2 − CH 4 heteroclathrate hydrate under mechanical loadings at various temperatures, pressures, and CO 2 saturations. Results show that all crystals exhibit brittle fracture behavior, and a crack first develops in the location where hydrogen bonds (HBs) in the hexagonal rings of the large 5 12 6 2 cages are parallel to the tensile direction. Increasing the temperature or CO 2 saturation leads to the decrease in Young's modulus and fracture strength of the CO 2 −CH 4 heteroclathrate hydrate. Particularly, abnormal mechanical strengthening of hydrates is observed when the CO 2 saturation is around 0.75, mainly attributed to the coupling of the lattice distortion with the host−guest interaction. HBs are the key factors to dominate the deformation of the CO 2 −CH 4 heteroclathrate hydrate. The slow decrease, rapid decrease, and abrupt increase in HB dynamics are corresponding to the elastic deformation, elastic−plastic deformation, and brittle fracture of the CO 2 −CH 4 heteroclathrate hydrate, respectively. With the further stretching after the brittle fracture, the water bridge made up of water molecules released by broken cages at high temperatures leads to different plasticity than at low temperatures and causes a further reduction of HBs. This work advances the understanding of mechanical stability of the gas hydrate, which is believed to be useful in the risk assessment of CO 2 replacing CH 4 from natural gas hydrates and the storage of CO 2 in gas hydrate reservoirs.

show abstract

Section: Models and Methodologymentioning

confidence: 99%

Section: Models and Methodologymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Mechanical Properties of a Structure I CO₂–CH₄ Heteroclathrate Hydrate: Insight from Molecular Dynamics Simulations

Meng

Liu

et al. 2021

Energy Fuels

View full text Add to dashboard Cite

show abstract

“…Dp = 2.86 nm is used for confined nucleation, and all calculations are performed with γ LH = 32 mJ/m 2 as estimated in ref. 48.…”

Section: Resultsmentioning

confidence: 99%

Reduced phase stability and faster formation/dissociation kinetics in confined methane hydrate

Jin

Coasne

2021

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

The mechanisms involved in the formation/dissociation of methane hydrate confined at the nanometer scale are unraveled using advanced molecular modeling techniques combined with a mesoscale thermodynamic approach. Using atom-scale simulations probing coexistence upon confinement and free energy calculations, phase stability of confined methane hydrate is shown to be restricted to a narrower temperature and pressure domain than its bulk counterpart. The melting point depression at a given pressure, which is consistent with available experimental data, is shown to be quantitatively described using the Gibbs–Thomson formalism if used with accurate estimates for the pore/liquid and pore/hydrate interfacial tensions. The metastability barrier upon hydrate formation and dissociation is found to decrease upon confinement, therefore providing a molecular-scale picture for the faster kinetics observed in experiments on confined gas hydrates. By considering different formation mechanisms—bulk homogeneous nucleation, external surface nucleation, and confined nucleation within the porosity—we identify a cross-over in the nucleation process; the critical nucleus formed in the pore corresponds either to a hemispherical cap or to a bridge nucleus depending on temperature, contact angle, and pore size. Using the classical nucleation theory, for both mechanisms, the typical induction time is shown to scale with the pore volume to surface ratio and hence the pore size. These findings for the critical nucleus and nucleation rate associated with such complex transitions provide a means to rationalize and predict methane hydrate formation in any porous media from simple thermodynamic data.

show abstract

“…7,9,10 We used a kpoint mesh comprised of 14 irreducible k-points, ensuring proper convergence with respect to the total energy for all systems. Although DFT is a 0 K calculation, it does not employ empirically determined interatomic potentials and is often called a first-principle calculation when compared to another commonly used approach for theoretical studies of hydrates, 12,13 molecular dynamics (MD). 34 We performed simulations of a single unit cell of sI hydrate.…”

Section: ■ Methodologymentioning

confidence: 99%

Heat Capacity, Thermal Expansion Coefficient, and Grüneisen Parameter of CH₄, CO₂, and C₂H₆ Hydrates and Ice I_h via Density Functional Theory and Phonon Calculations

Mathews

Servio

Rey

2020

Crystal Growth & Design

Self Cite

View full text Add to dashboard Cite

Thermal properties of gas hydrates and their underlying fundamental characterization are limited and incomplete but crucial in ongoing basic science research and technological applications. The constant volume heat capacity, the constant pressure heat capacity, the volumetric thermal expansion coefficient, and the Grüneisen parameter of methane, ethane, ethylene oxide, carbon dioxide, and empty structure I hydrates, and of hexagonal ice, as functions of temperature from 0 to 300 K, were calculated using the integration of density functional theory (DFT) simulations at 0 K and phonon calculations at higher temperatures. At low temperatures, DFT predictions replicated experimental values of constant pressure heat capacity for hydrates and ice accurately. Notably, the constant volume heat capacity was lower than when compared with literature values calculated with molecular dynamics (MD) and closer to actual data. Guest molecules were found to contribute slightly more than their ideal gas heat capacities to the overall property of the system. DFT underestimated the thermal expansion coefficient in all cases. The ethane and carbon dioxide hydrates demonstrated behavior that was markedly different when compared to methane and empty hydrates, and hexagonal ice. The Grüneisen parameter was calculated for all systems. DFT overestimated the value of the parameter for filled hydrates and hexagonal ice when compared to experimental hexagonal ice values. Altogether, this systematic atomistic study contributes to the technological applications and basic material science of these crystals whose properties are of significant importance in the fields of energy and the environment and provides a potential input to MD simulations thanks to its performance at low temperatures.

show abstract

Multiscale Modeling and Simulation of Water and Methane Hydrate Crystal Interface

Cited by 20 publications

References 89 publications

Mechanical Properties of a Structure I CO₂–CH₄ Heteroclathrate Hydrate: Insight from Molecular Dynamics Simulations

Mechanical Properties of a Structure I CO₂–CH₄ Heteroclathrate Hydrate: Insight from Molecular Dynamics Simulations

Reduced phase stability and faster formation/dissociation kinetics in confined methane hydrate

Heat Capacity, Thermal Expansion Coefficient, and Grüneisen Parameter of CH₄, CO₂, and C₂H₆ Hydrates and Ice I_h via Density Functional Theory and Phonon Calculations

Contact Info

Product

Resources

About

Multiscale Modeling and Simulation of Water and Methane Hydrate Crystal Interface

Cited by 20 publications

References 89 publications

Mechanical Properties of a Structure I CO2–CH4 Heteroclathrate Hydrate: Insight from Molecular Dynamics Simulations

Mechanical Properties of a Structure I CO2–CH4 Heteroclathrate Hydrate: Insight from Molecular Dynamics Simulations

Reduced phase stability and faster formation/dissociation kinetics in confined methane hydrate

Heat Capacity, Thermal Expansion Coefficient, and Grüneisen Parameter of CH4, CO2, and C2H6 Hydrates and Ice Ih via Density Functional Theory and Phonon Calculations

Contact Info

Product

Resources

About

Mechanical Properties of a Structure I CO₂–CH₄ Heteroclathrate Hydrate: Insight from Molecular Dynamics Simulations

Mechanical Properties of a Structure I CO₂–CH₄ Heteroclathrate Hydrate: Insight from Molecular Dynamics Simulations

Heat Capacity, Thermal Expansion Coefficient, and Grüneisen Parameter of CH₄, CO₂, and C₂H₆ Hydrates and Ice I_h via Density Functional Theory and Phonon Calculations