Molecular Simulation on Hydrate Nucleation in the Presence of Initial Ih Ice and Nanobubble

Abstract

Molecular dynamics simulations were used to compare the importance of the molecular diffusion process and the Ih ice interface for CO2 hydrate nucleation under mild conditions. CO2 molecules were adsorbed on the ice surface, resulting in an increasing number of CO2 molecules around the ice interface for a short time. However, as a result of the low driving force, the ice interface vanished quickly. The 512 and 51262 cages accounted for the majority of hydrate cages. In the case of empty cages, the 512 cage was more likely to exist in the hydrate cluster. Furthermore, only the largest hydrate cluster grew and existed in the system, while separate small clusters had shorter lifetimes and eventually vanished. Our theoretical findings served as a useful guideline for understanding the molecular diffusion behaviors of guest molecules during the CO2 hydrate growth process at a mild simulation condition with the ice interface.