[In situ Raman spectroscopic observation of micro-processes of methane hydrate formation and dissociation].
Guang Pu Xue Yu Guang Pu Fen Xi
; 31(6): 1524-8, 2011 Jun.
Article
em Zh
| MEDLINE
| ID: mdl-21847925
ABSTRACT
Micro laser Raman spectroscopic technique was used for in situ observation of the micro-processes of methane hydrate formed and decomposed in a high pressure transparent capillary. The changes in clathrate structure of methane hydrate were investigated during these processes. The results show that, during hydrate formation, the Raman peak (2 917 cm(-1)) of methane gas gradually splits into two peaks (2 905 and 2 915 cm(-1)) representing large and small cages, respectively, suggesting that the dissolved methane molecules go into two different chemical environments. In the meantime, the hydrogen bonds interaction is strengthened because water is changing from liquid to solid state gradually. As a result, the O-H stretching vibrations of water shift to lower wavenumber. During the decomposition process of methane hydrates, the Raman peaks of the methane molecules both in the large and small cages gradually clear up, and finally turn into a single peak of methane gas. The experimental results show that laser Raman spectroscopy can accurately demonstrate some relevant information of hydrate crystal structure changes during the formation and dissociation processes of methane hydrate.
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Base de dados:
MEDLINE
Idioma:
Zh
Revista:
Guang Pu Xue Yu Guang Pu Fen Xi
Ano de publicação:
2011
Tipo de documento:
Article
País de afiliação:
China