Design studies on granulation processes in a fluidized bed

The process of granulation is widely used in manufacturing particulate solid materials in order to produce a desired size or shape, especially when some particular physical properties are required. It can be used to manufacture product with improved qualities such as more uniform structure, non dusting, non caking and more resistance to mechanical shocks and protective coatings. It has been used on an industrial scale in the manufacture of many products including inorganic salts, fertilizers, pharmaceuticals, food, ceramic, steel, water purification, mineral beneficiation, and powder metallurgy. It is evident from the literature, the mechanism of granulation is complex. It depends on type of material being granulated and also by the method of running the process. It is essential to carry out laboratory scale experiments with the materials to be used before starting the design of any industrial scale granulator. The experimental setup consists of a main glass fluidization column having an ID of 10.16cm and 24cm height. This glass column is placed over a mild steel column of the same diameter and height 98cm. The binder solution was fed through a 2mm stainless steel tube and the compressed air from a 6.35mm tube at the tip of the atomiser. The binder solution was atomized due to the impingement of the air jet. The present investigation is to study the concept of granule formation by individual drops and to quantify the relationship between drop size and granule size by direct measurement. It has been shown that the mechanism and kinetics of granule growth in fluidized bed granulation process and important conclusions are presented in the paper.