6. Techniques for improving the fluidization of cohesive powders

As explained above, cohesive powders can sometimes be fluidized in the form of agglomerates. In most cases, however, fluidization of this type of powder can pose several problems:

• particle entrainment and elutriation: the aeration rate required to form and fluidize agglomerates is much higher than the minimum fluidization rate for individual particles. The result is significant elutriation, even with APF fluidization;

• Deterioration in material and heat transfer: although agglomeration enables certain powders to be fluidized, it also leads to a reduction in the specific surface area of available solids and a deterioration in material and heat transfer;

• defluidization of a large part of the layer (at the bottom of the bed);

• fluidization impossible:...