Bubble-Size Distribution in a Fluidized Bed by the Hot-Wire Scope Technique

Abstract

A multi-channel hot-wires system called “Hot-Wire Scope” is a device which can detect all bubbles of more than one centimeter diameter passing a horizontal plane at any height in fluidized beds.
Observation by “Hot-Wire Scope” in a bed of FCC particles showed that the horizontal bubble diameter has a bi-modal distribution under a large bed height vs. bed diameter ratio (L_s/D_T_??_10), and at low gas velocity and at lower bed height, the distribution of bubbles becomes a monomodal or a log-normal form.
From cine-films and visual observation at the wall, the bed is seen to be composed of three regions, viz., a lower region where intensive particle movement is occurring, a middle region where bubble coalescence is progressing, and an upper region where bubble size distribution becomes a bi-modal form.