Particle Size Control by Torque Measurements in Fluidized Beds during Drying and Granulation from Solutions

摘要

The fluidized bed process presented in this paper is suitable to recover solids from solution inudform of granules. Solution is sprayed into the bed and, as the solvent evaporates, solidudmaterial is deposited on the surface of fluidizing particles. During this process, particleudgrowth takes place by surface layering and/or agglomeration. A special grinder is used in theudfluidized bed to control particle growth by causing selective disintegration of large particles.udFor steady state operation, the most important task is to determine the existing particle sizeuddistribution in the fluidized bed. A special method was developed to measure torque andudstress fluctuations in the bed of particles. Using a correlation between torque and particle size,udthis method and device can be used for direct control of the rotation speed of the grinder toudproduce granules of given size in the fluidized bed. In this paper, the results of torqueudmeasurements and their correlation with particle size are presented.