Reports: ND951991-ND9: Clathrate Hydrate Formation Behaviors in Amphiphilic Particle-Laden Interfaces
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This project aims at elucidating hydrate formation behaviors at hydrate-forming gas/oil-water interfaces by injecting nano-particles into the interfaces. There are quite a few outcomes from the research activity of the second year. We have investigated the hydrate formation behavior at oil-hydrate-water interfaces in the presence of hydrophobic silica nano-particles (average size: 7nm) and understood their hydrate inhibition in the vicinity of interfaces. The hydrate conversion becomes low and the complete conversion time is delayed as the nanoparticle concentration increases up to 1.5 wt.% based on the weight of the oil phase. The conical hydrate crystals vividly shrink and distort their shape in the presence of the nanoparticles [1]. However, the application of 2wt. % nanoparticles to the interface totally prevents hydrate formation and the conical hydrate crystals do not appear. The degree of hydrate inhibition has been quantified in a high-pressure micro-differential scanning calorimeter. A main role of the nanoparticles in inhibiting clathrate hydrate formation is that the hydrophobic particles disperse the oil-water interface and prevent the contact between hydrate former and water. In addition to this inhibition study, we carried out thermodynamic and spectroscopic studies of methane hydrate formation with heterocyclic compounds (pyrrole & pyridine). It is remarkable that even if the two heterocyclic compounds retain hydrate inhibiting functional groups, they have promoted the hydrate formation of the methane-water system [2]. Another important aspect is that one of sulfur-containing compounds in crude oil is thiophene which turns out to be a hydrate former and accelerate the binary hydrate formation in the presence of methane [3].
References:
1. M. Cha, S. Baek, J. Morris, and J. W. Lee, “Hydrophobic particle effects on hydrate crystal growth at the water – oil interface,” Chemistry Asian Journal, 9(1), 261–267 (2014).
2. M. Cha, H. Lee, and J. W. Lee, “Thermodynamic and spectroscopic identification of methane enclathration in the binary heterocyclic compound hydrates,” J. Phys. Chem. C, 117 (45), 23515–23521 (2013).
3. Minjun Cha, Seungjun Baek, Huen Lee, Jae W. Lee, “Inclusion of thiophene as a co-guest in structure II hydrate with methane gas,” RSC Advances, 4 (50), 26176 – 26180 (2014).
