Large scale preparation of microbubbles by multi-channel ceramic membranes: Hydrodynamics and mass transfer characteristics

Microbubbles have potential applications in chemical engineering, water treatment, and medicine. By designing multi-channel ceramic membrane distributors, large scale preparation of microbubbles is achieved in a co-current bubble column. Oxygen and water are used as interacting gas-liquid phases. Gas holdup, bubble size distribution, and mass transfer rate are influenced by the membrane pore size, superficial gas velocity, and cross flow velocity. The empirical correlations for gas holdup and volumetric mass transfer coefficient are formulated and good agreement with experimental data is obtained. The multi-channel ceramic membranes can successfully produce a lot of microbubbles, resulting in larger values of gas holdup, volumetric mass transfer coefficient, and equilibrium dissolved oxygen concentrations as compared to the conventional gas sparger. These findings will aid the development of gas-liquid reactors with high performances.