TY - JOUR
T1 - Elasticity and Stability of Clathrate Hydrate
T2 - Role of Guest Molecule Motions
AU - Jia, Jihui
AU - Liang, Yunfeng
AU - Tsuji, Takeshi
AU - Murata, Sumihiko
AU - Matsuoka, Toshifumi
N1 - Publisher Copyright:
© 2017 The Author(s).
PY - 2017/12/1
Y1 - 2017/12/1
N2 - 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.
AB - 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.
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U2 - 10.1038/s41598-017-01369-0
DO - 10.1038/s41598-017-01369-0
M3 - Article
C2 - 28465527
AN - SCOPUS:85018360498
SN - 2045-2322
VL - 7
JO - Scientific reports
JF - Scientific reports
IS - 1
M1 - 1290
ER -
