Comparative study of the combustion properties of briquettes produced from blends of mung beans shell, uncarbonized and carbonized sawdust

Abstract

In this research, the combustion properties of the briquette produced by blending mung beans shell (MBS) with carbonized danta wood sawdust was compared with that of the briquette produced by blending MBS with uncarbonized danta wood sawdust. The briquettes wereproduced atdifferentsawdust to biomass ratios (100%:0, 70%:30%, 50%: 50%, 30%: 70% and 100%:0). Cassava starch was used as a binder. Proximate analysis (moisture content, ash content, volatile matter and fixed carbon) and combustion properties (calorific value, ignition time, burning time, burning rate, specific fuel consumption and thermal efficiency) were calculated using standard methods. The results of the analyses showed that 100% sawdust briquette samples had the lowest moisture content, 4.74±0.00 for carbonized sawdust and 6.76±0.02 for uncarbonized sawdust.100% uncarbonized and carbonized sawdust briquette samples had a fixed carbon of 68.93±0.02 and 87.46%, Ash content:3.70±0.00% and 2.18±0.04%,volatile matter: 20.61±0.00 and 5.61±0.04 and calorific value: 29.401±0.0 MJ/Kg and 32.532±0.05 MJ/Kg respectively.The ignition time increase with increase in biomass load for uncarbonized sawdust samples and decrease with increase in biomass load for carbonized sawdust briquette samples. The burning time decreased from 86±0.57mins (70% sawdust + 30% biomass) to 70±0.57mins (100% biomass) for the carbonized sawdust briquette samples and for the uncarbonized, it ranged from 68±0.00 (70% sawdust + 30% biomass) to 71.6±0.57 mins (30% sawdust + 70% biomass) and then dropped to 68±0.57(100% biomass load). The burning rate decreased in carbonizedbriquette samples and increased in uncarbonized briquette samples with increase in biomass load. The specific fuel consumption for carbonized and uncarbonized sawdust briquette sample decreased with increase in MBS load. 100% carbonized and uncarbonized sawdust briquette samples had a thermal efficiency of 8.78 and 16.47 respectively. It can be concluded that blend of carbonized sawdust and mung beans shell will make a better fuel due to better combustion properties than the uncarbonized sawdust samples.