Influence of the bed mass on its fluidization characteristics

Two series of fluidization tests were carried out on two test models with catalyst, alumina and sand particles to determine the bed mass influence on the characteristics at the minimum of fluidization. The main conclusions of the present study are: (i) the measured minimum fluidization velocities increased with the inventory whatever were the solid and the test rig used; (ii) the measured bed porosity at minimum fluidization decreased with the increase of the bed inventory; (iii) the definition of the minimum fluidization velocity by the balance between weight and drag forces and some usual mathematical modeling attempts were not able to describe the minimum fluidization increase with the bed inventory, (iv) the addition of a complementary consolidation effect in the force balance was able to match the obtained experimental results; (v) the consolidation effect sorted out the solids in the same order than the one given by their flowability as measured in shearing test. (C) 2003 Published by Elsevier B.V.