Hydrodynamics of gas‐agitated liquid‐liquid dispersions

Abstract

Gas-agitated liquid-liquid dispersions arise in applications as diverse as direct hydrogenation processes for bitumen and coal, and the manufacture of iron and steel. The transfer of gas-phase constituents to the dispersed liquid phase and /or elution of dispersed-phase drops have been identified as potential limiting phenomena in these processes. Consequently, mean drop size and drop size distribution are key design variables. In this paper, the impact of gas flux and the physical properties of dispersed-phase constituents on the steadystate size distribution of liquid drops in lean liquid-liquid dispersions is quantified. The physical properties of the dispersed phase are shown to have a significant impact on drop size and drop-size distribution at low gas fluxes. Sauter mean drop size is correlated using theoretical models for drop break-up and coalescence. All results are compared with stirred tank analogues.

Solid distribution in a slurry bubble column with two immiscible liquid phases

“…They concluded that the addition of kerosene to water reduces the gas holdup, which is the same behavior observed when solid particles are added to gas-liquid systems. Hatzikiriakos et al (1990) reached the same conclusion in the experimental study of bubble columns whosi liquids were mixtures of water and organic compounds. Tht reduction in gas holdup has been attributed to the inc-ease in the apparent viscosity of the liquid (taken as a pseudosingle phase) due to the presence of dispersed drops.…”

Fine drop recovery in batch gas-agitated liquid–liquid systems

“…Coulaloglou and Tavlarides (1977) descrïbed coalescence fiequency as the product of the collision efficiency and the coalescence efficiency. Hatzikiriakos et al (1990) presented a summary of collision frequency predictions, drop rupture and drop-drop coalescence in gas-agitated liquid-liquid dispersions. They noted that coalescence eficiency is assumed to be unity or less, and there is always a discrepancy between predicted and measured values.…”

Gas Evolution Rates in Supersaturated Water-in-Oil Emulsions at Elevated Pressures

“…Also, aeration affects the droplet size distribution, thereby necessitating the study of emulsion droplet size on gas evolution. A significant amount of work has been presented in the literature to understand the phase interaction of liquid-liquid-gas systems for gas-agitated tanks. − They observed that the gas bubbled through the emulsions leads to continuous droplet coalescence/breakup.…”