Optimisation of Sorghum Pelletisation Using a Vertical Roller-Type Pelletiser: A Sustainable Approach To Agricultural Waste-To-Energy Conversion

Bio pellets serve as an eco-friendly alternative for energy production, utilising renewable crops to produce clean energy while supporting agricultural sustainability. This study aims to design and test the performance of a roller-type pellet press for sorghum biopellets. The machine was designed to mix sorghum with other ingredients to increase its calorific value. The testing of performance used sorghum plants of the bioguma variety from sorghum farmers at a seed moisture content of 20–30% after harvest at 105–110 days after planting (DAP) directly from the sorghum field. The results of testing the performance of the pelletiser moulding machine show that the working capacity of the machine is 100–130 kg·h⁻¹. This capacity is influenced by the roller rotation, the rotation of the drive motor, and the moisture content of the sorghum biopelet raw material. The average pelletising efficiency was 98.80%, while the loss rate ranged from 0 to 1%. In addition, the thermogravimetric and derivative thermogravimetric analysis showed that sorghum, rice husk, and their blends have different thermal behaviours, with the sorghum-rice husk blend showing potential as an efficient biomass feedstock for bioenergy production.