Comparative Assessment of Bio-Oils from Agriculture Biomass Waste and Conventional Fossil Fuels: Evaluating Their Potential as Sustainable Industrial Fuel Alternatives
Abstract
The growing demand for sustainable energy and the environmental impacts of fossil fuel dependence have intensified interest in biomass-derived fuels, particularly in developing countries such as Nigeria where agricultural residues remain largely underutilized. This study assessed bio-oils obtained from agricultural biomass in comparison to traditional fossil fuels as a source of industrial energy. Using a vertical silo reactor, bio-oils were produced from mimosa seed pods, banana peels, and cashew nut shells via three thermochemical procedures: torrefaction (200–300 °C), slow pyrolysis (300–500 °C) and fast pyrolysis (>600 °C). The resulting bio-oils were characterized in terms of key physicochemical and fuel properties, including density, viscosity, calorific value, water content, flash point, cloud point, sulphur content, and ash content, and benchmarked against diesel (EN 590), kerosene (ASTM D1655) and heavy fuel oil (ISO 8217 RMG 380) standards. The highest bio-oil yields were obtained through fast pyrolysis, where banana peels yielded a maximum of 65 mL, while mimosa seed pods and cashew nut shells each yielded 35 mL. Cashew nut shell bio-oil had the most favourable fuel properties, including the highest density (0.86 g/cm3), calorific value (31.0 MJ/kg) and flash point (106 °C), suggesting high energy capacity and a higher level of safety performance. Banana peel bio-oil showed greater chemical stability (pH 6.80), and mimosa-derived bio-oil exhibited favourable volatility and cold-flow behaviour. All bio-oils had low sulphur (less than 0.031 wt%) and ash (less than 0.15 wt%) levels, indicating cleaner combustion compared to conventional fossil fuels. Overall, cashew nut shell bio-oil was the most viable diesel and kerosene replacement, though additional upgrading or blending is necessary to close the remaining performance gaps. This study highlights the potential of bio-oil as a transitional fuel in developing countries with minimal energy infrastructure, using readily available agricultural waste.