Production of carbonized briquettes from candlenut shells using unripe banana peelings as the binder

Abstract

This study investigated the fuel characteristics and performance efficiency of biomass briquettes made from carbonized candlenut shells, in combination with an organic binder derived from boiled banana peels. These peels, typically considered agro-waste, were selected for their adhesive properties and environmental sustainability. Four distinct briquette samples were formulated, each characterized by a specific binder-to-char mass ratio: 0.24, 0.50, 0.75, and 0.80, which were chosen to evaluate the effect of increasing binder concentration on various physical and combustion-related properties of the briquettes. The samples underwent a series of standardized laboratory tests to determine their calorific value, moisture content, ash content, bulk density, mechanical durability, and drop resistance. The results revealed a consistent trend whereby increasing the binder proportion generally led to a decrease in calorific value and burning rate, attributed to the relatively lower energy density of the banana peel binder compared to the carbonized candlenut shell. However, higher binder content was positively correlated with improvements in mechanical durability, cohesion, and resistance to breakage, likely due to the enhanced binding effect and increased starch and fiber content from the boiled banana peels. Among the four samples, the briquette with a binder-to-char ratio of 0.50 demonstrated the most optimal balance between thermal efficiency and physical robustness, making it the most practical choice for domestic energy applications that require moderate heat output and reasonable handling strength. On the other hand, samples with higher binder ratios (0.75 and 0.80) exhibited longer ignition times and slower burning rates, characteristics that could be advantageous in scenarios requiring sustained heat release over extended periods, such as slow cooking or space heating