Building Stronger Biomass: How Particle Size Affects the Physical and Mechanical Properties of Khaya senegalensis Fuel Pellets

Biomass has gained significant attention as a renewable energy source due to its potential to reduce dependency on fossil fuels and lower carbon emissions. Among various biomass-derived fuels, pelletized biomass offers enhanced energy density, improved combustion efficiency, and ease of handling and storage. Khaya senegalensis, a fast-growing tree that thrives in suboptimal conditions, requires regular pruning, leading to significant biomass waste. This study examines the influence of feedstock particle size on the mechanical properties of Khaya senegalensis fuel pellets. Biomass trimmings from Khaya tree branches were collected, processed into wood chips, and ground into five particle sizes (0.1, 0.3, 0.5, 1, and 2 mm) before pelletization. The pellets were produced under constant moisture content, pressure, temperature, and binder percentage. A one-factor-at-a-time (OFAT) approach was employed, with each process repeated three times to ensure consistency. The mechanical properties analyzed include unit density, durability, axial compressive strength, and diametral compressive strength. Experimental data are analyzed using analysis of variance (ANOVA) to examine correlations between feedstock particle sizes and mechanical properties. This study establishes that particle size plays a crucial role in determining the physical and mechanical properties of Khaya senegalensis wood pellets. The results indicate that finer particles (0.15 mm) contribute to higher unit density and durability, whereas coarser particles (1.00 mm) enhance compressive strength.