Production and characterization of fuel briquette from avocado fruit residue generated at Yirgalem Integrated Agro-processing Industrial Park, Ethiopia

In Ethiopia, rising energy demand and continued dependence on traditional biomass accelerate deforestation and harmful emission of greenhouse and indoor air pollutant gases, while the waste management systems in most agro-processing industries are poor, and the wastes are mostly disposed of in open areas with non-economic return and adverse environmental effects. This study, therefore, investigated the eco-friendly fuel-briquette production potential of avocado seed and peel wastes (ASPW) generated at Yirgalem Integrated Agroprocessing Industrial Park (YIAIP). The annual generation rate of ASPW in the YIAIP was estimated in dry weight base. ASPW was carbonized at 375 ± 25°C for 6 hours, and briquetting was done by densifying the char using locally manufactured hydraulic pressing machine. The annual fuel briquette production potential of ASWP was estimated to be 2,965.83 tons, and the proximate analysis revealed that fuel briquette possessed 7.7%, 26.5%, 41.63%, and 27.7% of dry matter, volatile solid, fixed carbon and ash contents, respectively. The calorific value of FB-ASPW (23.20 MJ/kg) was found to be substantially higher than that of commonly used fuelwoods (15 MMJ/kg), but lower than that of Acacia decurrens charcoal (31.16 MJ/kg). FB-ASPW exhibited longer ignition time (15.5 min) and lower burning rate (1.13 g/min). The annual fuelwood substitution and GHG emission reduction potential of FB-ASPW wear estimated to be 4591 and 8588 tons, respectively. Meanwhile, combustion of FB-ASPW emitted 20%, 94% and 30% less CO, PM2.5 and PM10 compared to open combustion of fuelwoods. Therefore, ASPW can be considered as eco-friendly sustainable feedstock for fuel briquette production.