Prediction of coating uniformity in batch fluidized-bed coating process

Coating of particulate materials in fluidized beds is a widely used technique to eliminate particle agglomeration, provide slow release of an active substance, or protect active ingredients. When thin polymer shells are applied on a particle surface, it is important to determine the process parameters that provide coating uniformity. In this study, the degree of coverage, defined as the fraction of the coated surface of the particles, is proposed as a quantitative criterion of coating uniformity. A new model for the batch fluidized-bed coating process is presented. The model allows prediction of the function of particle distribution according to the degree of coverage at a given process time and thereby enables assessment of coating uniformity. An algorithm for the numerical solution of model equations for a batch fluidized-bed coater is described. The influences of the main process parameters on the coating uniformity were shown. © 2021 Chinese Society of Particuology and Institute of Process Engineering, Chinese Academy of Sciences