Hydrodynamics and mixing characteristics in an ejector-induced downflow slurry bubble column (EIDSBC)

Slurry reactors have attracted the attention of researchers over the years due to its widespread applications and importance in various processes in chemical and biochemical industries. This article has been attempted to study the gas holdup (epsilon(g)), bubble size (d(vs)), the three-phase friction factor (f(TPL)), bubble generated turbulent energy (C-B), the dispersion coefficient of bubble motion (E-b) and velocity characteristic factor (k) in an ejector-induced downflow slurry bubble column within a range of superficial gas, slurry velocities and particle diameter of 0.04-0.14 m/s, 0.85 x 10(-2)-2.55 x 10(-2) m/s and 2.21-96.0 mu m respectively. The effects of these different operating variables on three-phase friction factor (f(TPL)), gas holdup (epsilon(g)), Sauter mean bubble diameter (d(vs)) and mixing characteristics are investigated experimentally. A functional relationship between three-phase friction factor and energy loss due to wettability of liquid with the solid surface (E-w) also developed. The gas holdup has been analyzed by the drift flux model and interpreted the same based on different significant dimensionless groups. The dispersion coefficient of bubble motion and the velocity characteristic factor are estimated as a function of slurry concentration. The present study in the modified downflow system may give insight into a further understanding and modeling of flow characteristics in industrial applications. (C) 2013 Elsevier B.V. All rights reserved.