Internal Structures in Fluid Beds of Different Scales: An Application of Electrical Capacitance Tomography.

Electrical capacitance tomographic imaging has been used to investigate the behaviour of smelter grade alumina in 200 mm, 300 mm and 600 mm ID fluid beds. Internal structures resulting from gas-solid interaction have been identified in each fluid bed. The scale of operation can be seen to influence the way the structures form and move through the bed, and these observations may account for the difficulty in modelling fluid bed behaviour at different scales of operation. Some aspects of the internal structures, such as the general size at a particular operating condition, can be seen to be relatively consistent in the different scale fluid beds.