Dissociation mechanism of propane hydrate with methanol additive: A molecular dynamics simulation

Abstract

Employing NPT molecular dynamics method with consistent valence force field, dissociation processes of propane hydrate with and without methanol additive are simulated at different temperatures and a constant pressure of 50 MPa. We analyze structural snapshots, radial distribution functions, density distributions, angle distributions, change of energies, mean square displacements and diffusion coefficients of two comparative models and find that encaging methanol molecules in the 512 cavities could enhance the diffusion behaviors of H2O and C3H8 molecules and shorten the decomposition time of propane hydrate. The hydroxyl group of methanol could form hydrogen bonds with the water cage skeleton, and destroy the original hydrogen bond balance of the hydrate simultaneously. Our theoretical results could provide a useful guideline to understand gas hydrate blocking wellbore in the production and transportation of oil and gas.