Simulation of the THF hydrate-water interfacial free energy from computer simulation

Area of Science:

• Computational chemistry
• Materials science
• Physical chemistry

Background:

• Understanding solid-fluid interfaces is crucial for various scientific and industrial applications.
• Hydrates, particularly those involving tetrahydrofuran (THF), play a significant role in natural gas storage and transport.
• Accurate determination of interfacial free energy is essential for predicting hydrate formation and stability.

Purpose of the Study:

• To calculate the tetrahydrofuran (THF) hydrate-water interfacial free energy using molecular dynamics simulations.
• To validate the accuracy of the mold integration-host methodology for hydrate-fluid interfaces.
• To compare simulation results with the limited experimental data available.

Main Methods:

• Molecular dynamics (MD) simulations were employed to determine the interfacial free energy.
• The mold integration-host methodology was utilized, extending the mold integration technique for hydrate-fluid systems.
• The TIP4P/Ice model for water and a rigid TraPPE model for THF were used, validated in prior work.

Main Results:

• The calculated THF hydrate-water interfacial free energy is 27(2) mJ/m2.
• This simulated value shows excellent agreement with the experimental data of 24(8) mJ/m2.
• This represents the first computational prediction of THF hydrate-water interfacial free energy.

Conclusions:

• The mold integration technique is a reliable method for predicting solid-fluid interfaces of complex structures, including sI and sII hydrates.
• The study validates the computational approach for determining hydrate interfacial properties.
• Accurate simulation of hydrate-water interfaces contributes to a better understanding of hydrate behavior.