Canadian Journal of Chemical Engineering, Vol.80, No.2, 177-185, 2002
Bubble characteristics of a scaled-down three-phase fluidized bed
Experiments were carried out in a 0.29 m diameter column to provide information on bubble characteristics relevant to an industrial three-phase fluidized bed reactor. Using a specially built electrical conductivity probe, together with a series of computer programs to gather and filter the data, local bubble properties (rise velocities, pierced chord lengths, frequencies, and direction of travel) were measured. The data are compared to existing correlations. Since the operating conditions were within the dispersed bubble regime, uniform bubbling was anticipated. However, the actual system indicated considerable non-uniformity, with individual bubbles, large swarms of bubbles and particles traveling at all angles. As a result, it is shown that bubble rise velocities are not necessarily a good measure of the bubble properties and must be vectorized to provide a good means of estimating gas hold-up.