Effect of Waste Cooking Oil and Tapioca Starch on Energy Content and Combustion Performance of Coconut Shell-Rice Husk Briquettes

Agricultural waste, such as coconut shells and rice husks, is widely utilized as solid fuel. Tapioca starch serves as the binder, while waste cooking oil (WCO) is used as an additive. Briquette performance is influenced by the type of biomass, binder, and additives used. However, the individual and interactive effects of WCO and tapioca starch on the performance of coconut shell-rice husk briquettes remain insufficiently established. This research focused on evaluating the effects of WCO and tapioca starch on calorific value (CV) and mass consumption rate. The briquettes' base composition consisted of 75% coconut shell charcoal and 25% rice husk charcoal, with WCO levels of 0%, 15%, 20%, and 25% and tapioca starch levels of 5%, 7%, and 9%. A factorial design with three replications was applied, and the effects of both factors and their interaction were analyzed using two-way analysis of variance. WCO significantly affected CV and mass consumption rate (p < 0.001). Tapioca starch significantly affected CV (p = 0.024), but not mass consumption rate (p = 0.056). The interaction significantly affected CV (p = 0.001), but not mass consumption rate (p = 0.895). The highest CV was 5183.76 cal/g at 25% WCO and 5% tapioca starch, while the lowest mass consumption rate was 0.0046 g/s at 25% WCO. The results indicate that WCO had a greater effect on briquette performance compared to tapioca starch.