The properties of sI methane hydrate dissociation at different temperatures are investigated using molecular dynamics (MD) simulations, focusing on the characteristics of structure of melting water that has memory effect. Upon melting, the clathrate structures of hydrate are damaged. The density of dissolved methane decreases as the melting temperature rises. There is a positive correlation between the density of dissociated water molecules and melting temperature. Most oxygen atoms of dissociated water molecules remain tetrahedrally coordinated whereas the hydrate-like torsion angles (H-O-O-H) are like that of normal water. Therefore, the tetrahedrally coordinated oxygen atoms are one of the factors contributing to the memory effect.
This work is supported by Open Fund (PLN1016) of State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation (Southwest Petroleum University). XC is supported by AFOSR (FA9550-12-1-0159), National Science Foundation (CMMI0643726), DARPA (W91CRB-11-C-0112), National Natural Science Foundation of China (11172231), and World Class University program through the National Research Foundation of Korea (R32-2008-000-20042-0).
- Memory effect
- molecular dynamics simulation