Effects of Impeller Speed, Atomising Air Flow Rate and Fluidising Temperature in Agitated Fluidised Bed Granulation of Cocoa-Milk Powders

Mechanically agitated fluid bed granulators with inserted impeller are currently favoured by the industry due to better particle mixing, heat transfer and effective particle growth. However, effects of operational variables such as impeller speed, atomising air flow rate and fluidising temperature on the physical characteristics of the generated granules are still not fully quantified. Scaling-up of industrial fluid bed granulation processes especially in the pharmaceutical industry are done empirically. In this paper, a study is described on the effects of impeller speed, atomising air flow rate and fluidising temperature on the flowability, moisture content, mean particle size and size distribution of the granulated cocoa-milk drink powder in an agitated fluid bed granulation process. Findings showed that when all the values of the three investigated operational parameters were increased, granules with better flowability characteristics, lower moisture content, smaller and more uniformed granules were obtained in the range tested.