Physical and combustion properties of composite briquette produced from wheat offal and carbonised hardwood sawdust

Abstract

With the growing population and the relative cost of conventional fuels, biomass resources, especially forest and agro-residues, can serve as an alternative and affordable energy source for the significant majority of the global population. Hence, this study investigated the physical and combustion properties of briquettes produced from a blend of carbonised sawdust and wheat offal at 20:80, 40:60, 60:40, 80:20, and 50:50 ratios (carbonised sawdust: wheat offal), using inorganic starch as a binder at 3%, 6%, and 9% inclusion levels. The study adopted a 3×5 factorial experiment in a completely randomised design and the briquettes produced were analysed based on their physical and combustion properties. The physical properties investigation revealed density ranged from 0.437 to 1.109 g/cm³.and the moisture content ranged from 3.14 to 9.87%. Briquettes made from an 80:20 biomass mixing ratio have the lowest moisture content (3.14%) and the highest compressed and relaxed density 1.109 g/cm³ and 0.601 g/cm^{3, respectively).} While the average volatile matter, ash content, fixed carbon, and heating values of the briquette ranged from 20.29 to 32.90%, 3.99 to 13.43%, 49.92 to 70.58%, and 28.158 to 31.029 MJ/kg, respectively. Briquettes made from a 20:80 biomass mixing ratio have the highest volatile matter content (32.90%), while those made from an 80:20 ratio have the highest fixed carbon content (70.58%) and heating value (31.092 MJ/kg). Findings of the study revealed that the briquette produced exhibited desirable properties, and that 80:20 biomass mixing and 6% binder inclusion produced briquettes with the most desirable characteristics and are thus recommended for producing quality composite briquettes from agricultural and forest-based residues