Particle size effect of CH4 hydrate for self-preservation

Satoshi Takeya, Tsutomu Uchida, Jiro Nagao, Ryo Ohmura, Wataru Shimada, Yasushi Kamata, Takao Ebinuma, Hideo Narita

Research output: Contribution to journalArticlepeer-review

115 Citations (Scopus)


In this study, we used time-resolved, energy-dispersive X-ray diffraction to study the dissociation of methane hydrate of various particle sizes into hexagonal ice and methane gas. The samples of polycrystalline methane hydrate were warmed from 135 to 263 K by slow warming at a rate of 1 K/min under atmospheric pressure. For particle sizes below about 250 μm, all the hydrates dissociated by about 21 OK. However, larger particle sizes had a high temperature regime in which the hydrate fraction decreased very little with increased temperature. For particle sizes of 1000-1400 μm, 20% of the hydrate remained even at 263 K. This apparent ability to retain hydrate at high temperatures is consistent with the oft-studied self-preservation effect in which the hydrate is encased by ice that greatly hinders the dissociation process due to methane gas diffusion through the ice. Confocal scanning microscope images of methane hydrate surface after partial dissociation revealed small grains of ice covering the CH4 hydrate surface. These results indicate that, for equal volumes of hydrate, larger hydrate particles can retain more CH4 gas at a given temperature than small particles.

Original languageEnglish
Pages (from-to)1383-1387
Number of pages5
JournalChemical Engineering Science
Issue number5
Publication statusPublished - 2005 Mar
Externally publishedYes


  • Confocal scanning microscope
  • Dissociation
  • Methane hydrate
  • Particle size
  • Self-preservation
  • X-ray diffraction

ASJC Scopus subject areas

  • General Chemistry
  • General Chemical Engineering
  • Industrial and Manufacturing Engineering


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