Investigation of Kinetics of Formation of Methane + Propane Hydrates by Molecular Dynamics Method in the Presence of Hydrate Seed and Sea Salt

Abstract

In the presented work we studied the process of nucleation and growth of methane and propane gas hydrate from a homogeneous solution by means of molecular dynamics. The aim is to assess the effect of hydrate seed on the growth rate and structure of the resulting hydrate in the presence of sea salt. This process was characterized via calculation of the number of long-lived hydrogen bonds and amount of hydrate and hydrate-like cavities, as well as the order parameter of the intermolecular torsion angles. It is shown that the kinetics of hydrate formation do not differ much in the cases of pure water and seawater. A seed crystal of hydrate on the contrary, not only increases the hydrate growth rate, but also makes the resulting structure more consistent with the cubic structure II hydrate.