Process optimization, economic and environmental analysis of biodiesel production from food waste using a citrus fruit peel biochar catalyst

The concept of sustainably reusing food waste to produce value-added byproducts, such as biodiesel, was studied. Food waste is an organic-rich source of lipids. An optimization study of the extraction of oil from food waste using a solvent for biodiesel production was undertaken. A biochar catalyst derived from citron ( Citrus medica ) peel containing a rich carbon source. A biodiesel yield of 96.3% was obtained under the optimized reaction conditions of a 1:10 oil to methanol molar ratio, 4 w% catalyst loading, reaction temperature of 55 °C, and a reaction time of 52 min. The conditions were optimized by response surface methodology with a central composite design. The biochar catalyst maintained a significant biodiesel yield for four cycles. This techno-economic analysis found that the annual plant revenue was $24,140,000 for a project lifetime of 20 years, the payback time was 3.16 years, the internal rate of return after tax was 39.92%, and the net present value at 10.0% interest was $55,017,000. A minimum biodiesel selling price of 0.46 $/kg was used, and the environmental sustainability of the produced biodiesel was assessed by a life cycle assessment. The impact of global warming potential on the FW-based biodiesel scenario was −3.967 kg CO 2 equivalent.