A review of clathrate hydrate nucleation, growth and decomposition studied using molecular dynamics simulation

Clathrate hydrates have a variety of applications ranging from natural gas storage, carbon dioxide sequestration, sea water desalination, gas separation etc. But the applications have still not reached the industrial stage and commercialization, although the concept has been demonstrated. In contrast, scale-up and demonstration of technologies are often done without proper understating of the process at the molecular level. One could always tune the process for better performance if proper knowledge of the process is built by understanding the same at the molecular level. Gas hydrate is essentially a crystallisation phenomenon, and since this is a multiple component and multi-phase system, the mechanism of nucleation and growth of hydrate has to be understood clearly. There are various theories behind the mechanism of hydrate nucleation. The theories talk about the stochastic nature and the steps leading to hydrate formation. Apart from that, there are variety of factors that affect hydrate decomposition. Many of these aspects become challenging to understand using meso and macro scale experiments. This is where Molecular Dynamics simulations plays a significant role. This review provides a molecular understanding of existing theories about nucleation & growth; further, factors affecting decomposition and the analysis techniques that are used to quantify such mechanism are also discussed.