Evaluation and characterization of biochar and briquettes from agricultural wastes for sustainable energy production

Abstract

Utilizing agricultural waste presents a promising solution for sustainable energy production and efficient waste management. This study focuses on producing and characterizing biochar and briquettes derived from the pyrolysis of seven abundant agricultural residues: Corn Cob, Groundnut shell, Rice Bran, Sawdust, Corn Straw, Dry Leaf, and Sugar Cane peel. The process involves subjecting the raw materials to controlled pyrolysis conditions and compaction into briquettes. FTIR analysis of biochar and raw dried samples, physicochemical analysis, and percentage yield on biochar, and calorific value on the briquettes produced were conducted to characterize the agricultural wastes. The physicochemical parameters of their biochar revealed significant differences in their composition. The pH ranged from 8.76 (Dry leaves) to 14.09 (Corn cob), Cation Exchange Capacity ranged from 1.55 − 7.39 cmol (+)/Kg, moisture content ranged from 2.74 − 6.36 %, volatile matter ranged from 1.85 – 6.87 %, ash content ranged from 16.70 – 79.25 %, and fixed carbon ranged from 11.30 – 72.07 %. The percentage yield of biochar from raw materials ranged from 8.6 % (sugarcane) to 27 % (groundnut shell), while the calorific value of the briquettes produced ranged from 1,868.57 KJ/g (sugarcane) to 55,511.2 KJ/g (Rice bran). The FTIR analysis revealed distinct spectral peaks for all charred waste compared to their raw counterparts, indicating structural changes during pyrolysis. These findings show the potential of some agricultural waste-derived briquettes as an efficient, sustainable, and renewable alternative fuel source. The characterization tests demonstrate their viability as a practical energy source, offering agricultural waste management solutions.