Computing Anisotropic Cavity Potential for Clathrate Hydrates.

Area of Science:

• Computational chemistry and materials science
• Thermodynamics and phase behavior of clathrate hydrates

Background:

• Understanding clathrate hydrate phase behavior is vital for energy production (natural gas hydrates), gas handling, and seawater desalination.
• Accurate quantification of guest-water interactions is key to understanding hydrate specificity, but computational limitations hinder analysis for large guests.

Purpose of the Study:

• To develop an advanced computational scheme for accurately estimating hydrate cavity potentials, addressing the challenge of large guest molecules.
• To validate the proposed computational method using experimental data for methane and binary hydrates.

Main Methods:

• Employed Møller-Plesset theory with advanced Dunning's basis sets, optimized to the complete basis limit using the Pauling point counterpoise weight.
• Validated the computational scheme against experimental data including Raman spectroscopy, second virial coefficient, and viscosity.
• Utilized experimental cage occupancy data for methane with tetrahydrofuran and cyclopentane as promoters.

Main Results:

• The proposed computational scheme demonstrates viability in accurately estimating hydrate cavity potentials.
• Successful attestation of the method using diverse experimental data for methane and binary hydrate systems.

Conclusions:

• The developed computational approach effectively overcomes previous limitations in modeling large guest-molecule interactions within clathrate hydrates.
• This advancement provides a reliable tool for predicting hydrate phase behavior and stability, with implications for various industrial applications.