Some aspects of hydrate formation and wetting

Experimental observations of gas hydrate formation have shown that, in the initial nucleation and crystallization process, water–oil emulsions may be generated, destabilized or even inverted. These phenomena are consistent with the effects of particles on emulsions. In this work we relate experimental observations of hydrate formation to the phenomenon of wettability. It is shown that details of hydrate wetting are important for both the morphology and the kinetics of the formed hydrates. For the cases of hydrate lenses and spheres, it is shown that the various wetting states can be illustrated and analyzed by using wetting diagrams. Metastability is a function of the surface energies of the hydrate formation, i.e., the wetting state, and it is shown that in some cases metastability vanishes, and thus hydrates nucleates instantly at all positive driving forces. The magnitude of buoyancy and turbulence forces acting on a hydrate sphere are compared to the capillary force and it is concluded that capillary energy dominates when the hydrate spheres is less than 1 mm.

The effective energy of hydrate formation at an interface or in bulk phases can be mapped in a wetting diagram, and used to describe both hydrate morphology and sub-cooling.Figure optionsDownload as PowerPoint slide