Influence of Production Variables on Eco-Friendly Briquettes from Coconut and Bambara Nut Shells

Abstract

This study investigates the influence of production variables on the properties of molasses-induced fuel briquettes from Coconut (Cocos nucifera L.) and Bambara nut (Vigna subterranea L. Verdc.) shells. The milled samples of both raw materials were mixed with molasses at ratios 100:20, 100:25, 100:30 and 100:35 by weight respectively, and briquetted using a Jack press at an average pressure of 1.2KN/m2. A 3x4 factorial experiment in completely randomized design was used. The briquettes produced were subjected to both physical and combustion tests. The tests revealed that majority of the variations in briquette properties were largely influenced by the type of biomass residues used while molasses’ content also contributed significant effect atp < 0.05. Coconut shell briquettes had higher compressed density though lower in relaxed form (0.80 g·cm-3vs 0.78 g·cm-3) when compared to Bambara nut shell briquettes (0.77 g.cm-3vs0.75 g.cm-3). Both physical and combustion properties were significantly improved when both bio-residue mixtures were used. Briquettes from the mixtures had the highest average fixed carbon and heating values of 85.21% and 32.80 MJ·kg-1 respectively, though it was 83.83% and 32.12 MJ·kg-1for coconut shell briquette and 82.18% and 32.03 MJ·kg-1for Bambara nut shell briquette. Therefore, based on physical and combustion characteristics, the best Bambara nut briquettes and its mixture with coconut shell were produced when molasses content was 30%. In contrast, the best coconut shell briquette was produced when molasses content was 35%. These two level are therefore recommended for production of quality briquettes from these agro-residues.

Keywords

• Eco-friendly fuel
• agro-residues
• briquette production
• molasses
• bambara nut