Two-Dimensional Lattice-Gas Model for Methane Clathrate Hydrates: Comparative Analysis with Experiments and Three-Dimensional Simulations

Abstract: Methane clathrate hydrates, particularly those with an sI structure, are significant due to their potential as energy resources and their impact on gas pipelines. In this study, a two-dimensional (2D) lattice-gas model is employed to investigate the main thermodynamic properties of methane clathrate hydrates. The proposed framework is validated through comparison with experimental data and more advanced three-dimensional (3D) simulations. Adsorption isotherms, dissociation enthalpy and phase stability of the sI structure are evaluated using Monte Carlo (MC) simulations in the grand canonical ensemble. The 2D adsorption isotherms closely align with both experimental data and 3D simulations, demonstrating the 2D model's ability to precisely represent both rigid and flexible sI structures. The dissociation enthalpy calculated using our approach (76.4 kJ/mol) excellently matches the experimental value (78 kJ/mol), confirming the model's accuracy. Furthermore, the phase diagram obtained from the Clausius-Clapeyron equation shows very good agreement with experimental data between 260 and 290 K, though deviations are observed above 290 K. These findings underscore the effectiveness and robustness of the 2D model in studying methane clathrate hydrates and suggest its potential applicability for investigating other guest species and hydrate structures.