Fluidised bed drying of powdered materials: Effects of operating conditions

The fluidized bed drying of powdered materials was studied with a focus on the modifications of the agglomerate population as a result of abrasion and fragmentation. A number of test were carried out in a Lexan (R) lab-scale fluidised bed with different granular materials, namely a pharmaceutical powder supplied by Novartis-Farma S.p.A., wheat bran, and a molecular sieve 13X, selected to effectively surrogate powders of interest in various industrial applications such as pharmaceuticals pills and adsorption pellets manufacture. The process was monitored to correlate the temperature and the flow rate of the fluidising gas, the temperature and the moisture level in the bed, the qualitative fluidisation patterns. Experimental results were further worked out to highlight the effects of inlet air temperature and gas velocity on process thermal efficiency. Bed material was characterized to assess the modifications of the population of agglomerates as a function of the operating conditions. (C) 2016 Elsevier B.V. All rights reserved.