Modeling of Interfacial Processes of Gas Hydrate Systems for Engineering Applications at Extreme Conditions

Gas hydrates are composed of a hydrogen bonded backbone of water molecules enclosing guest molecules in cages. While the equilibrium formation conditions lie in the megapascal range for gas hydrates, experimental conditions of formation and engineering environment involve extreme pressures in the gigapascal range. This project circumvents these issues by using molecular dynamics (MD) simulations to study gas hydrates. This work uses MD to characterize the temperature and pressure effects on the interfacial tension, energy of interfaces, and growth rate of natural gas hydrates understand their performance in extreme environments and prove that advanced computational characterization techniques explain structural and transport properties under extreme environments. Our work has shown that there is excellent agreement between sI methane hydrates and experimental values, with the interfacial energy decreasing with temperature. Preliminary results show that the sII natural gas hydrates show the same behavior. We have confirmed the presence of a novel pre-melting layer at the interface between the structures and produced temperature/pressure of surface tension. This information yields data to determine which conditions favor or hinder hydrate formation in applications of interest.