Fluidization behavior of vibrated and aerated beds of starch powders

Batch experimental work on the fluidization hydrodynamic and entrainment phenomena of cohesive starch powders was studied. Results show that fluidization can be realized as vibration break particle-particle bond in the bed. The higher U., values compared to predictions indicate the formation of agglomerates in the bed. This has increased the residence time of fines to reduce material loss by entrainment. It was found that using starch powders as feed materials, entrainment was only in the range of 0.5-1.7% of the total fines (should be entrained) in the bed. As has also been found by other workers, the entrainment rate constants of group C decrease as particle size decreases. By adapting the criterion proposed by Rietema (1984) as well as Ma and Kato (1998), it was found in this case that the critical cohesion number, N-coh* is 19.