Abstract
In the present study, we analytically tackle the development of a prediction model with the experiment as a counterpart. The model separate two stages: (i) CO_2 hydrate is generated from at the interface, and propagated of hydrate under CO_2 hydrate without condition and ; (ii) CO_2 hydrate grew for the case that the hydrate exists. In developing the prediction model, it is necessary to elucidate the diffusion process of CO_2 molecule and H_2O molecule in hydrates. It is, however, difficult to measure experimentally the molecular diffusivity in CO_2 hydrates under high-pressure condition. In this study, we used molecular dynamics simulations to model the diffusion properties of both molecules in hydrates. First, validity of molecule behavior is confirmed that structure was broken at CO_2 hydrate did not exist condition. As a result of calculation varied water vacancies, the vacancy play an important role for molecule behavior and diffusion of each molecule in hydrates.
