Modification of Biochar Pellets Made from Sawdust Using Torrefaction and Additives to Increase Calorific Value

Energy demand worldwide continues to rise. In 2020, Indonesia's energy supply was primarily sourced from coal (49.67%), oil (6.74%), natural gas (28.9%), and renewable energy (14.71%). This reliance on fossil fuels has a negative environmental impact. Biomass presents a viable renewable energy source. Sawdust, a readily available biomass waste in Indonesia, holds significant potential. While torrefaction can enhance its fuel characteristics, it alone is insufficient to maximize the heating value of sawdust biochar. Therefore, this study proposes the addition of additives to further increase the heating value. Furthermore, the additive-assisted biochar will be pelletized for easier storage and utilization. This paper reviews existing literature on these processes and proposes an approach for maximizing the calorific value of sawdust biochar pellets. The objectives are to synthesize current understanding regarding the impact of torrefaction temperature and time, and additive concentration on heating value; to identify potential statistical optimum conditions; and to discuss characterization methods for the resulting biochar pellets and their components. This work draws upon research conducted at the Advanced Material Laboratory (AMaL), Department of Chemical Engineering, Diponegoro University.