EVALUATION OF BINDER COMPATIBILITY IN OPTIMISED PALM KERNEL SHELL-COAL BLENDS FOR ASH REDUCTION AND ENERGY OPTIMISATION SUSTAINABILITY

This study investigated the effects of three locally sourced binders—cassava starch (CST), wastepaper (WP), and Styrofoam (SF)—on the synergistic combustion of palm kernel shell (PKS) and coal pellets for ash reduction and energy optimisation. Pellets were produced at two blend ratios (10% PKS:90% coal and 20% PKS:80% coal) with a constant binder composition of 30%. The samples were characterised using bomb calorimetry for calorific value, proximate analysis for moisture, volatile matter, ash, and fixed carbon content, and X-ray fluorescence for ultimate analysis (carbon, hydrogen, nitrogen, sulphur, and oxygen). The control samples (binderless) exhibited the highest calorific values (19.98–21.06 MJ/kg), while binder-enhanced pellets showed lower values (12.07-18.11 MJ/kg). Proximate analysis revealed that binder addition significantly reduced ash content, with cassava starch achieving the greatest reduction of 46% (from 19.72% to 10.59%) in 20% PKS blends, and wastepaper demonstrating the lowest ash content (11.95%) in 10% PKS blends. Ultimate analysis showed that the addition of wastepaper elevated the carbon content to 70.28% in 20% PKS blends, while cassava starch optimised the balance between fixed carbon (43.70%) and volatile matter (43.96%). Sulphur content increased with binder addition, particularly with wastepaper (1.00%), highlighting trade-offs in emissions. The 20% PKS blend with a cassava starch binder emerged as the optimal formulation, achieving substantial ash reduction, an acceptable calorific value (17.00 MJ/kg), and promising emission-reduction potential. This research demonstrates that binder selection critically influences fuel properties and provides validation parameters for developing sustainable binder-enhanced PKS-coal pellets as a cleaner energy alternative for co-firing applications.