Molecular dynamics characterization of the water-methane, ethane, and propane gas mixture interfaces

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

doi:10.1016/j.ces.2019.01.051

Cited by 24 publications

(14 citation statements)

References 55 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Thus far, the majority of the MD simulation studies of liquid–vapor interfacial properties of hydrocarbons have focused on systems containing water, − while comparatively fewer have been applied to non-aqueous mixtures of different hydrocarbons or hydrocarbons with CO 2 . Mejía et al used coarse-grained MD simulations together with pendant drop experiments and the square gradient theory model to find IFT, densities, and concentration profiles along the interfacial region for CO 2 / n -decane at 344.15 K and CO 2 / n -eicosane at 323.15 K over a pressure range from 0.1 to 10.35 MPa.…”

Section: Introductionmentioning

confidence: 99%

Molecular Dynamics Simulations of the Vapor–Liquid Equilibria in CO₂/n-Pentane, Propane/n-Pentane, and Propane/n-Hexane Binary Mixtures

2021

View full text Add to dashboard Cite

Molecular dynamics (MD) simulations were used to study vapor− liquid equilibrium interfacial properties of n-alkane and n-alkane/CO 2 mixtures over a wide range of pressure and temperature conditions. The simulation methodology, based on CHARMM molecular mechanics force field with long-range Lennard-Jones potentials, was first validated against experimental interfacial tension (IFT) data for two pure n-alkanes (n-pentane and n-heptane). Subsequently, liquid−vapor equilibria of CO 2 /n-pentane, propane/n-pentane, and propane/n-hexane mixtures were investigated at temperatures from 296 to 403 K and pressures from 0.2 to 6 MPa. The IFT, liquid and vapor phase densities, and molecular compositions of the liquid and vapor phases and of the interface were analyzed. The calculated mixture IFTs were in excellent agreement with experiments. Likewise, calculated phase densities closely matched values obtained from the equation of state (EOS) fitted to the experimental data. Examination of the density profiles, particularly in the liquid−vapor transition regions, provided a molecular-level rationalization for the observed trends in the IFT as a function of both molecular composition and temperature. Finally, two variants of the empirical parachor model commonly used for predicting the IFT, the Weinaug−Katz and Hugill−Van Welsenes equations, were tested for their accuracy in reproducing the MD simulation results. The IFT prediction accuracies of both equations were nearly identical, implying that the simpler Weinaug−Katz model is sufficient to describe the IFT of the studied systems.

show abstract

Section: Introductionmentioning

confidence: 99%

Molecular Dynamics Simulations of the Vapor–Liquid Equilibria in CO₂/n-Pentane, Propane/n-Pentane, and Propane/n-Hexane Binary Mixtures

2021

View full text Add to dashboard Cite

show abstract

“…Changes in the compositions of the gas phase and hydrates observed over time during hydrate growth suggested the influence of kinetic and transport factors in addition to thermodynamics of the system. Mirzaeifard et al 17 used molecular dynamic simulation to study various interfacial phenomena in a mixture of natural gas (CH 4 + C 2 H 6 + C 3 H 8 ) and liquid water. Further insights on employing natural gas mixtures for the study of hydrate-based natural gas storage and transportation technology can be found in the review paper by Veluswamy et al 18 Recently, a simple method that can rapidly form mixed methane hydrates in the presence of methane and 5.6 mol % tetrahydrofuran (THF) in an unstirred reactor configuration at moderate pressures and near ambient temperature conditions was demonstrated.…”

Section: Introductionmentioning

confidence: 99%

Macroscopic Kinetic Investigations on Mixed Natural Gas Hydrate Formation for Gas Storage Application

et al. 2020

View full text Add to dashboard Cite

Solidified natural gas (SNG) technology via clathrate hydrates is a promising technology for the long-term and largescale storage of natural gas, owing to multifaceted benefits offered, including environmentally benign, compact, and safest mode of gas storage in comparison to conventional methods. In this study, we investigate the macroscopic kinetics of natural gas hydrate formation using a C1 (93%)−C2 (5%)−C3 (2%) gas mixture. The main objective is to examine the effect of the presence of low concentrations of higher hydrocarbons (ethane and propane) in influencing the natural gas hydrate formation kinetics along with the additional presence of a thermodynamic promoter, tetrahydrofuran. Experiments were performed to study the effect of pressure (driving force) on the mixed natural gas hydrate formation kinetics in an unstirred reactor configuration. Plausibility of the improvement in kinetics of mixed natural gas hydrate formation in the presence of an amino acid (kinetic promoter) was also attempted. Concentration of 300 ppm of tryptophan was found to be effective in enhancing the mixed natural hydrate formation kinetics at experimental conditions of 283.2 K and 5.0 MPa, albeit a minor drop in gas uptake. Results from this study will be helpful in advancing the SNG technology toward commercial implementation.

show abstract

“…A favorable interaction between the hydrogen bonds and the molecules at the interfacial zone leads to the molecular adsorption. In the liquid water–methane gas mixture, a peak in the number of hydrogen bonds has been observed to explain adsorption onto the interface. ,,, Conversely, Figure shows a minimum in the hydrogen bond density profile near the interface of the liquid water–methane clathrate mixture at the different temperature and pressure regimes. Temperature increases trigger larger thermal fluctuations at the interface that diminish the stable hydrogen-bonding network and, consequently, its favorable interaction with the bulk water molecules, which leads to less molecular adsorption and higher tension.…”

Section: Resultsmentioning

confidence: 99%

Multiscale Modeling and Simulation of Water and Methane Hydrate Crystal Interface

Mirzaeifard

Servio

Rey

2019

Crystal Growth & Design

Self Cite

View full text Add to dashboard Cite

Water–methane hydrate interfaces are ubiquitous in oil and gas technologies and in Nature. The structure and properties of this liquid/crystal interface plays a significant role in transport phenomena between the bulk phases. In this paper, we use molecular dynamics techniques to characterize the liquid water–crystalline methane hydrate in the bulk and, particularly, the interface. We show that the interfacial mechanical approach based on the novel constant normal pressure-cross-sectional area (NPNAT) ensemble with a computational slab length equal to the lattice parameter of the methane clathrates can accurately predict the interfacial free energy of a curved interface. Notably, the computational platform for the interfacial tension characterization includes contributions from elastic strains. In the studied temperature and pressure ranges, we find that the interfacial tension slightly increases with temperature upturn or pressure drop due to less disordered orientation and dispersed distribution of the molecules at the interface. We generate a full molecular-level characterization by computing the excess enthalpy and stress, local density profile, radial distribution function, hydrogen bonding density, and charge distribution to confirm the observed interfacial tension trend, which significantly contributes to the evolving understanding of gas hydrate formation.

show abstract

Molecular dynamics characterization of the water-methane, ethane, and propane gas mixture interfaces

Cited by 24 publications

References 55 publications

Molecular Dynamics Simulations of the Vapor–Liquid Equilibria in CO₂/n-Pentane, Propane/n-Pentane, and Propane/n-Hexane Binary Mixtures

Molecular Dynamics Simulations of the Vapor–Liquid Equilibria in CO₂/n-Pentane, Propane/n-Pentane, and Propane/n-Hexane Binary Mixtures

Macroscopic Kinetic Investigations on Mixed Natural Gas Hydrate Formation for Gas Storage Application

Multiscale Modeling and Simulation of Water and Methane Hydrate Crystal Interface

Contact Info

Product

Resources

About

Molecular dynamics characterization of the water-methane, ethane, and propane gas mixture interfaces

Cited by 24 publications

References 55 publications

Molecular Dynamics Simulations of the Vapor–Liquid Equilibria in CO2/n-Pentane, Propane/n-Pentane, and Propane/n-Hexane Binary Mixtures

Molecular Dynamics Simulations of the Vapor–Liquid Equilibria in CO2/n-Pentane, Propane/n-Pentane, and Propane/n-Hexane Binary Mixtures

Macroscopic Kinetic Investigations on Mixed Natural Gas Hydrate Formation for Gas Storage Application

Multiscale Modeling and Simulation of Water and Methane Hydrate Crystal Interface

Contact Info

Product

Resources

About

Molecular Dynamics Simulations of the Vapor–Liquid Equilibria in CO₂/n-Pentane, Propane/n-Pentane, and Propane/n-Hexane Binary Mixtures

Molecular Dynamics Simulations of the Vapor–Liquid Equilibria in CO₂/n-Pentane, Propane/n-Pentane, and Propane/n-Hexane Binary Mixtures