prediction of methane hydrate growth kinetics by using non-equilibrium thermodynamics: a molecular dynamic simulation study

In the present work, the kinetics of methane hydrate growth was predicted by the molecular dynamic simulation. the results showed that the number of methane molecules and the thickness of solid phase in the layers near the interfaces significantly increase implying that the growth proceeds in these layers. a kinetics model was considered to predict the hydrate growth kinetics that it is based on the irreversible and non-equilibrium thermodynamics. the proposed model is a two-parametric model with the thermodynamic function of affinity as a driving force that it relates to an irreversible chemical process which naturally occurs. the results showed that one parameter of model was estimated to be a nearly constant value, but another one is a kinetic parameter dependent on the operational conditions. the hydrate formation kinetics improves as the concentration of methane increases at the interfaces. in addition, the system pressure and subcooling are proportional to the driving force, and the higher driving force causes faster growth kinetics. the model can well predict the entire process of hydrate formation, since the affinity shows that the hydrate formation is a process proceeding on a natural path.