Sustainability vs suitability in granulation

Abstract

Little is known about the sustainability of competing granulation technologies, despite them being key and widespread industrial processes. This study has evaluated the sustainability of four prominent granulation technology pathways with respect to material wastage (Yield %), Specific Time (Hours/kg) and Specific Energy (kWh/kg). The Fluidised Bed Granulator proved to be the most material efficient while the Roller Compactor was the most time efficient. The energy efficiency of the granulators improved in the following order: Twin Screw Granulator, Fluidised Bed Granulator, High Shear Granulator and Roller Compactor. The wet granulation techniques proved to be the more energy inefficient technologies due to energy expensive sub stages such as drying. This was especially the case with the Twin Screw Granulator and High Shear Granulator where the actual granulating equipment only accounted for around 13% and 15% of the total energy consumed by the entire production pathway. Comparatively, the drying stage accounted for around 45% and 84% of the Twin Screw Granulation and High Shear Granulation production pathways. The different granulation technologies were shown to produce granules with significantly varying properties due to changing granule shape and porosities. The use of visual tools such as parallel co-ordinate graphs and radar plots alongside analytical methods such as priority scoring are suggested as important tools to help manufacturers choose the optimum process pathway based on these varying sustainability and granule suitability factors.