The effect of lattice constant on the storage capacity of hydrogen hydrates: a Monte Carlo study

ABSTRACT

We use grand canonical Monte Carlo simulations to examine the effect of the size of hydrate cavities (as reflected through the lattice constant of the hydrate unit cell) on the efficiency of clathrate hydrates in storing hydrogen gas. With this approach, the hydrate lattice is treated as a solid substrate where gas absorption takes place. Of practical interests are cases, where the lattice-size parameters are changed in such a way that they can promote/enhance multiple cavity occupancy, namely the presence of more than one guest-gas molecule in the same hydrate cavity. This phenomenon is commonly observed in the case of hydrogen hydrates and could increase their storage capacity. A parametric analysis is also carried out to quantify the correlation between the change in the lattice constant and the storage capacity since small changes in the size of the crystal unit cell may induce significant changes in the storage capacity especially in cases where multiple cavity occupancy occurs.

KEYWORDS:

• Clathrate hydrate
• grand canonical Monte Carlo
• cavity occupancy
• hydrogen hydrate
• gas storage capacity

Acknowledgments

We are grateful to the High Performance Computing Cluster of the Environmental Research Laboratory (NCSR “Demokritos”) for generous computational resource allocation.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

NPRP [award number 6–1547–2–632]; Greek Scholarship Foundation.