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Structural stability of methane hydrates in porous medium: Raman spectroscopic study
Vangala Dhanunjana Chari1, Pinnelli S R Prasad2, Sarabu Ramana Murthy3
1Gas Hydrates Division, National Geophysical Research Institute (CSIR-NGRI), Council of Scientific and Industrial Research, Hyderabad 500007, India; Department of Physics, Osmania University, Hyderabad 500007, India.
Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
|November 19, 2013
Summary
Methane hydrates (MH) are more stable in hollow silica spheres than solid ones. Raman spectroscopy reveals hydrates in hollow silica last hours and up to 273 K, while those in solid silica dissociate quickly.
Area of Science:
- Materials Science
- Geochemistry
- Physical Chemistry
Background:
- Methane hydrates (MH) are crystalline ice-like structures composed of methane gas trapped within water molecules.
- Understanding the stability of methane hydrates is crucial for energy resource management and climate change studies.
- Silica matrices offer a potential confinement environment for synthesizing and studying methane hydrates.
Purpose of the Study:
- To investigate the thermal and temporal stability of methane hydrates synthesized within solid and hollow spherical silica matrices.
- To compare the hydrate growth patterns and structural characteristics in different silica confinement.
- To determine the influence of silica matrix morphology on methane hydrate stability.
Main Methods:
- Synthesis of methane hydrates within spherical silica matrices (solid and hollow, ~70 μm diameter).
- Raman spectroscopy was employed to analyze the structural features and stability of the synthesized hydrates.
- Hydrate samples were subjected to varying temperature and pressure conditions (0.1 MPa, 153 K to 273 K) to assess temporal and thermal stability.
Main Results:
- Raman spectroscopy confirmed structural resemblance of methane hydrates across different silica matrices.
- Homogeneous hydrate growth was observed in hollow silica matrices, contrasting with heterogeneous growth in solid silica.
- Methane hydrates in hollow silica demonstrated stability for hours at 153 K and up to ~273 K at 0.1 MPa.
- Methane hydrates within solid silica matrices were found to be unstable, dissociating within 2 hours under similar conditions.
Conclusions:
- The morphology of the silica matrix significantly impacts the temporal and thermal stability of synthesized methane hydrates.
- Hollow silica spheres provide a favorable environment for stable methane hydrate formation and preservation.
- These findings have implications for the storage and transport of methane hydrates and understanding their geological behavior.
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