Optimization of bio-briquettes production from cassava stems co-blended with sisal bole bagasse using response surface methodology

Agnes Nshoma Msobi, Department of Chemical and Processing Engineering, College of Engineering and Technology, University of Dar es Salaam P. O. Box 35131, Dar es Salaam, TanzaniaFollow
Neema O. Msuya, Department of Chemical and Process Engineering, College of Engineering and Technology, University of Dar es Salaam, P.O. Box 35091, Dar es Salaam, TanzaniaFollow
Kando Khalifa Janga, Department of Chemical and Processing Engineering, College of Engineering and Technology, University of Dar es Salaam P. O. Box 35131, Dar es Salaam, TanzaniaFollow

Section

Physical Sciences

Abstract

This research aimed at producing bio-briquettes from cassava stems and sisal bole bagasse as an alternative source of cooking energy. A Response Surface Methodology (RSM) with Face - Centered Central Composite Design (FCCCD) featured a multi-objective optimization of the effect of the production parameters, focusing on maximizing char yield and Higher Heating Value (HHV) of the produced briquette while minimizing carbonization temperature and residence time. The findings showed that bio-briquettes produced at the lowest temperature (250 ℃) and residence time (30 min) and the blending ratio of 75% by 25% had the highest char yield of 76.92% and HHV of 20.84 MJ/kg. Char yield and HHV improved at lower carbonization temperature and residence time with higher blending ratios, although elevated temperatures enhanced HHV through devolatilization; therefore, optimization identified a balanced trade-off between energy densification and process efficiency. Biomass characterization showed that Sisal Bole Bagasse (SSB) had both higher Fixed carbon and HHV compared to cassava stem (CS), and the carbonization increased the HHV of the produced briquette by 24.9% and 16% over SSB and CS, respectively. It is recommended that for a good quality briquette using the same materials, the blending ratio should contain a higher percentage of the sisal bole bagasse than the cassava stems

Recommended Citation

Msobi, Agnes Nshoma; Msuya, Neema O.; and Janga, Kando Khalifa (2026) "Optimization of bio-briquettes production from cassava stems co-blended with sisal bole bagasse using response surface methodology," Tanzania Journal of Science: Vol. 52: Iss. 2, Article 7.
Available at:https://doi.org/10.65085/2507-7961.2252