Investigation of the Morphology of Secondary Nucleation of Hydrate from a Water Droplet in Liquid Cyclopentane

In the present work, the effects of formed hydrates on the cyclopentane hydrate morphology at different schoolings were initially investigated. It was found that faceted hydrate film quickly propagated from nucleation points along the droplet surface at ΔT sub = 6.7 K. Water then exudated from the junctions of hydrate facets and formed a snow-like hydrate after the primary propagation. Infrequent hydrate formation modes were also initially observed at the same subcooling. These modes were characterized by the growth of the crystals pinned on the droplet surface or suspended in the inner droplet at the hydrate–water interface rather than the formation of a hydrate shell. At ΔT sub = 3.7 K, a hydrate shell with intertwined multiple dents gradually covered the droplet, and outward plate-like/needle-like crystals and subsequent snow-like crystals were observed in turn. At ΔT sub = 2.2 K, only the formation of a hydrate shell with intertwined multiple dents was observed. The presence of hydrate debris leads to the formation of a coarser hydrate shell and a significantly shortened duration time. The formation that occurred in the presence of contact with hydrate particles suggested that the morphology and duration time of the newly formed hydrate significantly depended upon the morphology of the contacted/inductive hydrate particle surface.