Analysis of constant rate period of spray drying of slurry

A model has been developed for spray drying of slurry: droplets with proper high solid content during the constant-rate period. The equations governing mass and heat transfer phenomena were numerically solved using the finite element method. The model is able to predict the crust formation as a function of slurry properties and operating parameters. For water-based suspension droplets of monodisperse silica particles, the effects of these parameters on granule morphology were simulated and the results were compared with the experimental data. Good agreement is reported between theory and experiment. The simulations demonstrated that the large primary-particle yields dense solid granules. The solid content of granules increases with slurry concentration when primary particles are smaller than a certain value. On the other hand, the preferred manner to obtain solid product granules for a given precursor slurry concentration is to start with initial droplets as small as possible at relatively low ambient temperature. (C) 2001 Elsevier Science Ltd. ALI rights reserved.