On the phase behaviors of hydrocarbon and noble gas clathrate hydrates

Last update: August 19, 2018

A paper from our group was published in J. Chem. Phys.

Tanaka, H., Yagasaki, T. & Matsumoto, M. On the phase behaviors of hydrocarbon and noble gas clathrate hydrates: Dissociation pressures, phase diagram, occupancies, and equilibrium with aqueous solution. J. Chem. Phys. 149, 074502 2018).

DOI: 10.1063/1.5044568

Clathrate hydrate represented by methane hydrate is a solid solution in which gas molecules and water are crystallized together. Usually, for crystals consisting of two or more components, the component ratio is a simple integer ratio. On the other hand, hydrates are called non-stoichiometric compounds, and composition ratios vary depending on temperature, pressure and the surrounding environment. For this reason, it is difficult to specify the composition ratio accurately and evaluate its stability in both experiments and simulations.

In this research, we have described a method to accurately estimate the range of possible composition ratios at arbitrary temperature pressure, without simulation, based on statistical mechanics theory. In Mars, or satellites of the outer planets, water and gas are present, but both pressure and temperature are low. Under such circumstances, it became possible to know under what conditions hydrates will be formed.

It was chosen as Featured Article of AIP (American Physical Society) and introduced at Scilight.

"Revisions to standard theory provide clues to understanding phase behavior of clathrate hydrates" by Adam Liebendorfer

DOI: 10.1063/1.5051832