Effects of carbon nanotube on methane hydrate formation by molecular dynamics simulation

Abstract

The development of gas hydrate technology is beneficial to achieve efficient storage and transportation of methane. The formation of methane hydrate in the presence of single and multiple CNTs was simulated by molecular dynamics applying NPT and NVE ensemble in this study. The cage identification method was applied to detect the number of simulated generated cages. Due to their unique tubular structure, high specific surface area, excellent thermal conductivity and their own activity, the addition of CNTs promoted the formation of hydrates, increased the generation rate and the number of generations, and reduced the nucleation time compared to the pure water system. Triple CNTs showed the best promotion effect under NVE ensemble, and the order of promotion was double CNTs (1.8 wt%) > single CNT (0.9 wt%) > triple CNTs (2.7 wt%) under NPT ensemble. The results show that CNTs facilitate the growth of methane hydrate and the promotion effect varies with concentration and temperature, which provides a functional microcosmic implication for future studies on methane storage and transportation.