FLUIDIZED-BED GRANULATION - GAS-FLOW, PARTICLE MOTION AND MOISTURE DISTRIBUTION

In fluidized bed granulation the liquid is often distributed by means of a two-fluid-nozzle that is positioned inside the bed. Then the wett ing process takes place in the jet that is formed by the atomizing air . A model has been derived for a free jet to calculate the particle an d gas velocities, the void fraction and the cross-sectional area of th e jet. The results are compared with experimental data for the particl e circulation time in the fluidized bed. Based on the particle and gas motion the liquid deposition is calculated, resulting in particle moi sture distributions. The influence of different parameters on the mois ture distribution and possible consequences on the granulation process are discussed. (C) 1997 Elsevier Science S.A.