The oil palm industry is one of the most important fruit crop sectors globally. However, there is an environmental issue related to the waste produced during the extraction of palm oil from fruit bunches, known as empty fruit bunch (EFB). Microwave-metal-assisted pyrolysis is considered a promising solution to efficiently transform EFB into biochar. In this study, EFB fibre was pyrolyzed in a cylindrical stainless-steel reactor with and without aluminium mesh. The pyrolysis of EFB was carried out for 30 min without aluminium mesh, and the pyrolysis time was varied to 20 min, 30 min and 40 min with aluminium mesh. This study showed that the presence of Al mesh and longer pyrolysis time can increase the energy contents of the biochar. The biochar produced from 40 min pyrolysis time with the presence of aluminium mesh, namely BC40-Al, possessed the most superior solid biofuel properties. The proximate analysis revealed that the BC40-Al contained 35.7 wt%. of fixed carbon. TGA showed that BC40-Al had the highest thermal stability compared to other biochar samples and raw EFB. The carbon content of BC40-Al was 78.4 wt%, and the higher heating value was 27.9 MJ/kg. The heating value of BC40-Al is better than lignite coal, and almost comparable to bituminous coal. However, despite excellent fuel characteristics, there is a concern regarding the ash slagging and fouling due to high K2O, CaO, SiO2 and Cl contents in the biochar samples. The authors have made a few suggestions on how to reduce the propensity of ash slagging and fouling.
