Elasticity and Stability of Clathrate Hydrate: Role of Guest Molecule Motions

Jihui Jia, Yunfeng Liang, Takeshi Tsuji, Sumihiko Murata, Toshifumi Matsuoka

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

Molecular dynamic simulations were performed to determine the elastic constants of carbon dioxide (CO2) and methane (CH4) hydrates at one hundred pressure-temperature data points, respectively. The conditions represent marine sediments and permafrost zones where gas hydrates occur. The shear modulus and Young's modulus of the CO2 hydrate increase anomalously with increasing temperature, whereas those of the CH4 hydrate decrease regularly with increase in temperature. We ascribe this anomaly to the kinetic behavior of the linear CO2 molecule, especially those in the small cages. The cavity space of the cage limits free rotational motion of the CO2 molecule at low temperature. With increase in temperature, the CO2 molecule can rotate easily, and enhance the stability and rigidity of the CO2 hydrate. Our work provides a key database for the elastic properties of gas hydrates, and molecular insights into stability changes of CO2 hydrate from high temperature of ~5 °C to low decomposition temperature of ~-150 °C.

Original languageEnglish
Article number1290
JournalScientific reports
Volume7
Issue number1
DOIs
Publication statusPublished - Dec 1 2017

All Science Journal Classification (ASJC) codes

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