Exploring hydration mechanism of salt ions on the methane hydrate formation: Insights from experiments, QM calculations and MD simulations

Abstract

A fundamental understanding of the hydration mechanism of salt ions on the methane hydrate formation would be beneficial for the interpretation of the reservoir formation mechanism and the development and utilization of natural gas hydrate. In this work, the hydration of salt ions (Na+ and Cl-) on the methane hydrate formation is investigated using experiments, quantum mechanics (QM) calculations and molecular dynamics (MD) simulations. The results show the salts ions firstly influence the orientation of the H2O molecules and then influence the OH symmetrical stretching vibrations by impacting the tetrahedral arrangement of H2O molecules after attaching the hydration-shell layers. The coupling process of the hydration and the mass transfer of salt ions influence the methane hydrate formation.