A GLOBAL COATING QUALITY MODEL FOR TOP-SPRAY FLUIDIZED BEDS: SPRAY SUB MODEL

Fluidized beds are amongst others used in industrial applications for coating particles. Little research has been performed in developing a quality model for a coating process. A quality model is able to predict the quality of the process in terms of coating thickness and uniformity and the occurrence of unwanted side-effects, including agglomeration, attrition and spray loss. The quality of the coating process in a fluidized bed is largely determined by the spray characteristics and the particle motion. A new quality model was developed for the coating process in a top-spray fluidized bed. The first step in the development of the new model was the creation of an accurate spray sub-model that describes the movement and the heat and mass balances of the droplets in the coating process. The second step was the creation of a particle sub-model that describes the movement and the heat and mass balances of the particles in the fluidized bed. The third and final step will be the development of the global coating quality model by combining the spray and the particle sub model. Experimental validation of the spray sub-model has already been carried out and is presented in this paper.