Investigation of Methane Hydrate Growth Using Molecular Dynamics Simulation

For the first time, molecular dynamics simulation is used to investigate steady-state methane hydrate growth in a system larger than 50 sI hydrate unit cells for durations greater than 100ns without employing artificial mass or heat transport constraints. Molecular dynamics simulations are initiated from partially ordered configurations, and as solid hydrate grows it replaces areas of the simulation box previously occupied by a methane and water vapor/liquid system. At the interface of growth, partially formed cages are observed to persist for up to 10 nanoseconds while halo-like hydrogen-bonded networks of water molecules eventually form the remainder of the cages. The estimated growth rates for these simulations are between 1.3 cm/s and 3.4 cm/s.