Comparative analysis of granule properties in continuous granulators

An experimental study into twin screw granulation (TSG) has been performed using a design of experiments (DoE) approach. The properties of the produced granules are compared to those reported previously from a range of continuous and batch granulation processes. The effect of processing parameters such as speed, temperature and binder content on granule strength and structure are analysed. Seeded granule structures were found to be present in all but one type of granulator (Extrudomix) and longer residence times were found to lead to maximum seeded structures with a batch Cyclomix granulator. Granule crushing strengths were found to be higher in TSG than all other continuous equipment and the optimum condition for the formation of stronger granules with the lowest variation was around 65.4 °C. Overall, an equipment-specific DoE approach was shown to be a useful method to establish the relationship between process parameters, structure and properties.