Electronic Thesis and Dissertation Repository


Master of Engineering Science


Chemical and Biochemical Engineering


Jesse Zhu


Gas-liquid-solid fluidized beds have been widely applied in wastewater treatment, however, the current method of wastewater process has several limitations. Hence, an improved method is in demand. A 3.5 height and 0.1534m inner diameter column was used to study the hydrodynamic characteristics of a bubble-induced three-phase inverse fluidized bed. Air, water and three types of low-density particles were employed as gas, liquid and solid phases.

The hydrodynamic properties in the bubble-induced three-phase fluidized bed were investigated to provide the basic information for the industrial process, such as flow regime, bed expansion ratio and phase holdups. A flow regime map containing fixed bed, initial expansion, transition regime, complete fluidization and freeboard regime is presented. The bed expansion ratio behaves like the conventional fluidized bed. The axial profiles of the phase holdups show that with increasing gas velocity, liquid holdup has a downward trend, while gas holdup has an upward trend. Solids holdup is irrelevant with the gas velocity. Based on the Richardson-Zaki equation, a preliminary model between the solids holdup and superficial gas velocity was built.