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Protocol for Measuring the Thermal Properties of a Supercooled Synthetic Sand-water-gas-methane Hydrate Sample
Published on: March 21, 2016
Raman studies of methane-ethane hydrate metastability
Hiroshi Ohno1, Timothy A Strobel, Steven F Dec
1Center for Hydrate Research, Colorado School of Mines, Golden, Colorado 80401, USA.
The Journal of Physical Chemistry. A
|February 13, 2009
Summary
Methane-ethane hydrate structural conversion was studied. A kinetic inhibitor accelerated conversion at 65% methane but slowed it at 93% methane, indicating complex interactions.
Area of Science:
- Geochemistry
- Materials Science
- Chemical Engineering
Background:
- Methane and ethane hydrates exist in different crystalline structures (sI, sII).
- Understanding hydrate structural interconversion is crucial for energy storage and geological processes.
- Kinetic hydrate inhibitors are used to prevent undesirable hydrate formation in industrial applications.
Purpose of the Study:
- To investigate the structural interconversion of methane-ethane hydrates.
- To evaluate the effect of methane concentration on hydrate structural stability.
- To determine the role of a kinetic hydrate inhibitor (poly(N-vinylcaprolactam)) in hydrate interconversion.
Main Methods:
- Synthesis of sI and sII methane-ethane hydrates using gas mixtures (65% and 93% methane in ethane).
- Raman spectroscopy was employed to monitor structural changes and interconversion rates.
- Experiments were conducted with and without the kinetic hydrate inhibitor, poly(N-vinylcaprolactam).
Main Results:
- Higher methane concentration accelerated the structural conversion rate of hydrates.
- The kinetic hydrate inhibitor increased conversion rate at 65% methane (sI stable).
- The inhibitor retarded conversion rate at 93% methane (sII stable), suggesting complex surface interactions.
Conclusions:
- Methane concentration significantly influences hydrate structural interconversion kinetics and thermodynamics.
- Poly(N-vinylcaprolactam) exhibits a concentration-dependent effect on methane-ethane hydrate structural conversion.
- The study highlights complex interactions between inhibitors, water, and guest molecules at hydrate crystal surfaces.
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