TY - JOUR
T1 - On the Thermodynamic Stability of Clathrate Hydrates VI
T2 - Complete Phase Diagram
AU - Tanaka, Hideki
AU - Yagasaki, Takuma
AU - Matsumoto, Masakazu
N1 - Funding Information:
The present work was supported by JSPS KAKENHI Grant Number 17K19106 and MEXT as “Priority Issue on Post-Kcomputer” (development of new fundamental technologies for high-efficiency energy creation, conversion/storage, and use). The authors are grateful to Prof. M. Taniguchi, Prof. K. Koga, and T. Nakayama for valuable discussions.
Publisher Copyright:
© 2017 American Chemical Society.
PY - 2018/1/11
Y1 - 2018/1/11
N2 - We develop a method to evaluate the thermodynamic stability of clathrate hydrates relative to host water and/or guest species. This enables to investigate complete phase behaviors of clathrate hydrates in the whole space of the thermodynamic variables, not only temperature and pressure but also composition, with only the intermolecular interactions as input parameters. A complete phase diagram of clathrate hydrate is settled with this method, specifically the region enclosed by the hydrate/water and hydrate/guest phase boundaries where a clathrate hydrate is the only stable phase. The method is applied to methane clathrate hydrate, which results in an excellent agreement in dissociation pressure with the experimental observations. It is found that the hydrate/water phase boundary is significantly affected by the phase transition of water from ice to liquid. This transition limits the stable area of the clathrate hydrate terminated at the dissociation temperature, which otherwise exhibits unphysical divergence. It is essential to choose a pressure as an independent variable so as to calculate the accurate phase equilibria in composition space. The present method establishes a pressure-temperature-composition relation for a single stable phase of clathrate hydrate as well as recovering its temperature dependence of the dissociation pressure.
AB - We develop a method to evaluate the thermodynamic stability of clathrate hydrates relative to host water and/or guest species. This enables to investigate complete phase behaviors of clathrate hydrates in the whole space of the thermodynamic variables, not only temperature and pressure but also composition, with only the intermolecular interactions as input parameters. A complete phase diagram of clathrate hydrate is settled with this method, specifically the region enclosed by the hydrate/water and hydrate/guest phase boundaries where a clathrate hydrate is the only stable phase. The method is applied to methane clathrate hydrate, which results in an excellent agreement in dissociation pressure with the experimental observations. It is found that the hydrate/water phase boundary is significantly affected by the phase transition of water from ice to liquid. This transition limits the stable area of the clathrate hydrate terminated at the dissociation temperature, which otherwise exhibits unphysical divergence. It is essential to choose a pressure as an independent variable so as to calculate the accurate phase equilibria in composition space. The present method establishes a pressure-temperature-composition relation for a single stable phase of clathrate hydrate as well as recovering its temperature dependence of the dissociation pressure.
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U2 - 10.1021/acs.jpcb.7b10581
DO - 10.1021/acs.jpcb.7b10581
M3 - Article
C2 - 29212321
AN - SCOPUS:85040570887
VL - 122
SP - 297
EP - 308
JO - Journal of Physical Chemistry B
JF - Journal of Physical Chemistry B
SN - 1520-6106
IS - 1
ER -