Study of solid-liquid fluidized bed using Electrical Impedance Tomography

S. A. Hashemia,b, R. S. Sandersa

aDepartment of Chemical and Materials Engineering, University of Alberta, Edmonton, AB, Canada, T6G 2V4

bSaskatchewan Research Council Pipe Flow Technology CentreTM, SK,Canada, S7N 2X8

Abstract

In this study, high speed Electrical Impedance Tomography (EIT) is used to measure local solids concentration and concentration fluctuations in a solid-liquid fluidized bed. Experiments were carried out in a 10.16 cm (i.d.) fluidized bed using 2 and 4 mm mono-sized spherical glass beads (ρs=2540 kg/m3) with water as the continuous phase. A reduced solid concentration in the central region of the bed, which is known to occur during the bubbly (aggregate) fluidization regime, was observed. Cross-sectional averaged solid concentrations collected over a range of fluidization velocities were compared with the Richardson-Zaki equation. Solid concentration fluctuation measurements were consistently higher in the near-wall region where particle-wall interactions are dominant. While others have measured solid concentration fluctuations averaged over the column cross section, this study provides further insight into the dynamic behaviour of liquid-solid fluidized beds through the measurement of local solid concentration fluctuations.

Keywords: Solid-liquid flow;Impedance tomography; concentration fluctuation