Insight on the stability of polycrystalline natural gas hydrates by molecular dynamics simulations

摘要: Abstract Gas hydrates have drawn considerable attention in the globe because of their importance environment and energy field. Although nature synthesized laboratory are polycrystalline materials, structures grain boundaries, stability, influence boundary on hydrate dissociation remain unclear. In this study, we conducted massive simulations CH4 CO2 to investigate these issues. We find boundaries natural gas exhibit complex cage featuring nonstandard cages may contain small bubbles. The can be periodically connected by repeated motifs defect containing 4- 8-membered rings. Examining thermal stability structures, our results show that for hydrates, process at hindered, where annealing structure further enhance effect. Consequently, found dissociate only when temperature is somewhat above bulk melting temperature, but not case hydrates. This indicates guest types both affect boundaries. Moreover, also investigated molecules greatly accelerate induce formation bubbles prefer bubbles, initiates with decomposition 51262 cages.