Optimal conditions to prepare fine globular granules with a multi-functional rotor processor.

Abstract The optimal manufacturing conditions to obtain fine globular granules with a narrow size of particle distribution were investigated for a multi-functional rotor processor. A fractional factorial design analysis was undertaken to find out the significant operational conditions influencing the following physical characteristics of the obtained granules: size distribution, roundness and water content. Operational conditions tested were binder flow rate, atomization pressure, slit air flow rate, rotating speed and temperature of inlet air. It was observed that: the proportion of fine particles (106–212 μm) was positively affected by the atomization pressure, while negatively affected by the slit air flow rate; and roundness and water content were positively affected by the binder flow rate. Furthermore, the multiple regression analysis enabled the identification of an optimal operating window for production of fine globular granules. Therefore, the present study demonstrated that the combination of experimental design and multiple regression analysis allows a better understanding of complicated granulating process of multi-functional rotor processor to obtain fine globular granules.