Microscopic Measurements and Modeling of Hydrate Formation Kinetics

• Published in: Annals of the New York Academy of Sciences
• Main Authors: SUBRAMANIAN, S., SLOAN, E. D.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2000
• Subjects: Methane hydrate
• Online Access: http://dx.doi.org/10.1111/j.1749-6632.2000.tb06813.x; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1749-6632.2000.tb06813.x; https://nyaspubs.onlinelibrary.wiley.com/doi/pdf/10.1111/j.1749-6632.2000.tb06813.x

A bstract : The frequency of the Raman band for methane dissolved in water indicates clustering of water molecules around methane molecules. By monitoring trends in the position of this band with pressure, it was determined that the clusters resemble CH 4 trapped in the 20‐coordinated small 5 12 cavity, the basic building block of clathrate hydrates. These methane‐water clusters act as precursors to hydrate cavity formation and their transformation to methane trapped in cavities of sI hydrate was monitored using time resolved Raman spectroscopy. The ratio of number of large to small cavities was obtained as a function of time. The formation of the large 5 12 6 2 cavity was determined to be slower than for the small 5 12 cavity. Based on these results, a mechanistic model of methane hydrate formation from the aqueous phase is proposed.