Hydrodynamics of gas-agitated liquid-liquid dispersions



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 constitutents 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 constitutents on the steady-state 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.