The effect of electric fields in methane hydrate growth and dissociation: A molecular dynamics simulation

摘要

Molecular dynamics simulation was employed to examine the growth and dissociation process of methane hydrate in the presence of static/oscillation electric fields at T = 260 K and P = 100 bars. The intensity of electric field was in range of 1.0-2.0 v/nm, and the frequency of applied e/m field was in range of 2.45 GHz-1.0 THz. Electric field would be a factor controlling the hydrate growth and dissociation because the migration of water molecules may be affected. Total energy of simulation system, final system configurations, hydrate-like methane numbers, radial distribution functions, H-bond numbers with simulation time, and dipole moment were analyzed. There is intensity threshold for a-field to exert an effect on methane hydrate. Static electric fields above the intensity threshold (1.5 v/nm) could push hydrate dissociation by inducing the arrangement of water molecules along the field. Cosine oscillation electric fields could promote both methane hydrate growth and dissociation, and there are different critical field magnitudes for different frequency e-fields to play positive roles in methane hydrate growth or dissociation. In order to promote methane hydrate dissociation, higher the e-field magnitude will need as the a-field frequency is higher.