A new method for the control of size of pellets in the melt pelletization process with a high shear mixer

The control of the melt pelletization process in an 8-1 high shear miser us ing specific energy consumption of the impeller motor was studied. Lactose was used as the bulk material with polyethylene glycol 3000 as a meltable b inder. The effects of binder concentration, mean particle size of bulk mate rial and post-melt impeller speed on the relationship of specific energy co nsumption and pellet growth were examined. Specific energy consumption was found to be a suitable tool for monitoring the melt pelletization process, and specific energy consumption correlated well with pellet growth. The mea n size of the pellets formed becomes correspondingly larger with increasing specific energy consumption. Concerning the impeller speed, specific energ y consumption is more useful as a tool for end-point control of the process than post-melt mixing time. Similar size pellets can be obtained with comp arable specific energy consumption, independent of the impeller speed. The control of pellet size requires a correlation between pellet growth and spe cific energy consumption that is established for the formulation and proces s conditions used, For this purpose, mathematical modelling of the pellet g rowth process is presented. The predictions of pellet growth by the mathema tical model are in agreement with the experimental findings.