Seungjun Baek

Hydrophobic Particle Effects on Hydrate Crystal Growth at the Water–Oil Interface

This study introduced hydrophobic silica nanoparticles (SiNPs) into an interface of aqueous and hydrate-forming oil phases and analyzed the inhibition of hydrate crystal growth after seeding the hydrate slurry. The hydrate inhibition performance was quantitatively identified by micro-differential scanning calorimetry (micro-DSC) experiments. Through the addition of 1.0 wt% of SiNPs into the water-oil interface, the hydrate crystal growth only occurred around the seeding position of cyclopentane (CP) hydrate slurry, and the growth of hydrate crystals was retarded. Upon a further increase in the SiNP concentration up to 2.0 wt%, the SiNP-laden interface completely prevented hydrate growth. We observed a hollow conical shape of hydrate crystals with 0.0 and 1.0 wt% of SiNPs, respectively, but the size and shape of the conical crystals was shrunken at 1.0 wt% of silica nanoparticles. However, the conical shape did not appear with an increased nanoparticle concentration of 2 wt%. These findings can provide insight into hydrate inhibition in oil and gas delivery lines, possibly with nanoparticles.

Inclusion of thiophene as a co-guest in a structure II hydrate with methane gas

Thiophene and its derivatives are found in crude oils and their molecular sizes indicate they could be clathrate hydrate formers. In this study, the formation of clathrate hydrates in the presence of thiophene and methane gas is identified through spectroscopic and thermodynamic investigations. Powder X-ray diffraction (PXRD) is used in order to identify the crystal structure of the binary (thiophene + CH4) clathrate hydrate, and PXRD patterns of the binary (thiophene + CH4) clathrate hydrate indicate the formation of structure II hydrate with methane gas. The unique inclusion and distribution of guest molecules such as thiophene and methane are verified through Raman spectroscopy. The thermodynamic stability of the binary (thiophene + CH4) clathrate hydrate is also investigated by using high pressure differential scanning calorimetry. The experimental results are valuable for a better understanding of the crystal structure, host–guest interaction and stability conditions in the binary (thiophene + CH4) clathrate hydrate.

Inhibition effects of activated carbon particles on gas hydrate formation at oil–water interfaces

This study presents the inhibition effects of activated carbon particles on the formation of cyclopentane and propane mixed hydrates in the presence of non-hydrate formers and a surfactant. Activated carbon particles gather around the interface between water and oil phases due to their hydrophobicity and this particle layer prevents water molecules from contacting any hydrate guests. The coexistence of cyclopentane and propane mixed hydrates was clearly observed through Raman spectroscopy. The Raman spectra showed that the propane and cyclopentane were enclathrated in the large cages of structure II hydrate. The inhibition efficiency of the activated carbon particles was quantified using high pressure micro differential scanning calorimetry (HP Micro-DSC). The dissociation enthalpies of the mixed hydrates were significantly reduced at 0.5 wt% of activated carbon particles based on the weight of the oil phase. At 1.0 wt% of activated carbon particles, the particle layer completely covered the interface and the seeding hydrate slurry could not penetrate into the water phase and thus hydrate growth was not observed over a 6 hour period. These results show that carbon particles may have good potential as kinetic hydrate inhibitors in offshore gas–oil pipelines.