Clathrate hydrate formation using liquid jets impinging on each other: An observational study using paired water jets or water and methylcyclohexane jets

This paper reports the experimental attempt at visually observing and characterizing the formation and/or growth of clathrate-hydrate crystals accompanying the impingement of two cylindrical jets of either the same liquid, water, or two mutually immiscible liquids, water and methylcyclohexane (MCH), in a difluoromethane (HFC-32) gas phase held at a constant pressure. We observed that the hydrate crystals intermittently emerged on the liquid sheet radially expanding from the point of the jet collision, flowed to the periphery of the sheet, and then engulfed in the droplets when they were disintegrated from the periphery of the sheet. The observations of the droplets falling in the gas phase indicated that even some of the droplets initially containing no hydrate started to be covered by hydrate films presumably as the result of delayed hydrate nucleation on the individual droplets. The measurements of the gas consumption rate due to hydrate formation showed that the ratio of the water-to-hydrate conversion and the efficiency of using the cool energy supplied by the liquid jets for hydrate formation tended to increase as the liquid flow rate per jet increased and thereby intensified the liquid atomization, indicating an increasing proportion of hydrate formation on the droplets with an increase in the liquid flow rate.