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International Conference on Gas Hydrates (ICGH) (6th : 2008)

RAMAN STUDIES OF METHANE-ETHANE HYDRATE STRUCTURAL TRANSITION Ohno, Hiroshi; Strobel, Timothy A.; Dec, Steven F.; Sloan, E. Dendy; Koh, Carolyn A.

Abstract

The inter-conversion of methane-ethane hydrate from metastable to stable structures was studied using Raman spectroscopy. To investigate factors controlling the inter-conversion, the rate of structural transition was measured at 59% and 93% methane in ethane. The observed slower structural conversion rate in the lower methane concentration atmosphere can be explained in terms of the differences in kinetics (mass transfer of gas and water rearrangement). Also, the effect of kinetic hydrate inhibitors, poly-N-vinylpyrrolidone (PVP) and polyethylene-oxide (PEO), on the hydrate metastability was investigated at 65% and 93% methane in ethane. PVP increased the conversion rate at 65% methane in ethane (sI is thermodynamically stable), but retarded the rate at 93% methane in ethane (sII is thermodynamically stable), indicating that the function of PVP depends on hydrate structure. PEO did not affect the structural transition considerably for either methane-ethane compositions.

Item Metadata

Title
RAMAN STUDIES OF METHANE-ETHANE HYDRATE STRUCTURAL TRANSITION
Creator
Ohno, Hiroshi; Strobel, Timothy A.; Dec, Steven F.; Sloan, E. Dendy; Koh, Carolyn A.
Contributor
University of British Columbia. Department of Chemical and Biological Engineering; International Conference on Gas Hydrates (6th : 2008 : Vancouver, B.C.)
Date Issued
2008-07
Description
The inter-conversion of methane-ethane hydrate from metastable to stable structures was studied using Raman spectroscopy. To investigate factors controlling the inter-conversion, the rate of structural transition was measured at 59% and 93% methane in ethane. The observed slower structural conversion rate in the lower methane concentration atmosphere can be explained in terms of the differences in kinetics (mass transfer of gas and water rearrangement). Also, the effect of kinetic hydrate inhibitors, poly-N-vinylpyrrolidone (PVP) and polyethylene-oxide (PEO), on the hydrate metastability was investigated at 65% and 93% methane in ethane. PVP increased the conversion rate at 65% methane in ethane (sI is thermodynamically stable), but retarded the rate at 93% methane in ethane (sII is thermodynamically stable), indicating that the function of PVP depends on hydrate structure. PEO did not affect the structural transition considerably for either methane-ethane compositions.
Extent
409015 bytes
Subject
Natural gases; Gas hydrates; Kinetic inhibitors
Genre
Conference Paper
Type
Text
File Format
application/pdf
Language
eng
Date Available
2016-11-21
Provider
Vancouver : University of British Columbia Library
Rights
Attribution-NonCommercial-NoDerivatives 4.0 International
DOI
10.14288/1.0041038
URI
http://hdl.handle.net/2429/1146
Affiliation
Non UBC
Citation
Ohno, Hiroshi; Strobel, Timothy A.; Dec, Steven F.; Sloan, E. Dendy; Koh, Carolyn A. 2008. RAMAN STUDIES OF METHANE-ETHANE HYDRATE STRUCTURAL TRANSITION. Proceedings of the 6th International Conference on Gas Hydrates (ICGH 2008), Vancouver, British Columbia, CANADA, July 6-10, 2008.
Peer Review Status
Unreviewed
Copyright Holder
Sloan, E. Dendy; Koh, Carolyn A.; Dec, Steven F.
Rights URI
http://creativecommons.org/licenses/by-nc-nd/4.0/
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Attribution-NonCommercial-NoDerivatives 4.0 International