Design and performance assessment of a pelleting machine for sustainable biomass pellet fuel production from plant residues

This study designs and develops an energy-efficient pelleting machine for crop residues, integrating the Finite Element Method (FEM) and experimental evaluations. Key performance parameters including machine productivity (M_p), pellet length (Pl), particle density (ρ_p), bulk density (ρ_b), hardness resistance (Hr), shear stress (τ), and pellet durability (Dp) were analyzed under varying conditions of moisture content (MC), molasses content (MLC), particle size (PS), and main shaft rotating speed (RS). Results showed that increasing MC, MLC, PS, and RS significantly improved pellet quality and efficiency. Peak Mp (99.4 kg h^-1) was achieved at 20% MC, 0.7 mm PS, and 100 rpm, while 15% MLC yielded the highest ρ_p (1147 kg m^-3), ρ_b (610 kg m^-3), Hr (447 N), and τ (3.6 MPa). Pellet durability reached 94%, highlighting the molasses' superior binding properties. Heatmap analysis confirmed strong correlations between MLC and critical pellet properties. The energy-efficient process consumed 128.45 kW h ton^-1, only 2.8% of the energy potential of cotton stalks, ensuring sustainability. This study introduces a novel approach to enhancing pellet quality while minimizing synthetic additives, demonstrating advancements in process efficiency. Future research should investigate advanced binder formulations, process automation, and the long-term stability of biomass pellets under various storage conditions.