Commercially Viable Biodiesel Production from High-FFA acid oils Using Pilot-Scale Hydrodynamic Cavitation
摘要
Despite their abundance and low cost, acid oils remain underutilized in large-scale biodiesel production using process intensification technique due to their very high free fatty acid (FFA) content, which poses significant challenges for efficient conversion. This study investigates the conversion of high FFA feedstocks-soya acid oil, rice bran acid oil, groundnut acid oil, and mixed acid oil (FFA: 65–92%)-into biodiesel using a 100 L/batch pilot-scale hydrodynamic cavitation reactor. The process of esterification followed by transesterification is facilitated by a 32-hole orifice plate, achieving > 95% FFA conversion with residual FFA content below 4% and delivering biodiesel yields above 90% across all feedstocks. Energy-based yield efficiencies achieved were (0.56 to 0.61) × 10− 3 kg/kJ in esterification and (0.86 to 0.89) × 10− 3 kg/kJ in transesterification, respectively, with combined yield efficiencies of (0.31 to 0.33) × 10− 3 kg/kJ, indicating consistent energy-efficient performance across feedstocks. Techno-economic assessment (TEA) confirmed that hydrodynamic cavitation enables commercial viability of biodiesel production at ≥ 200 L/day, offering rapid payback (PB) (2.48 years), high profitability (return on investment (ROI): 41.09%; internal rate of return (IRR): 41%), and strong energy efficiency (EROI of 6.56) compared to conventional processes. The biodiesel met both ASTM D6751 and EN 14,214 specifications, as confirmed by FTIR, GC-FID, and 1H NMR analyses, in terms of conversion rate and physicochemical properties, confirming its environmental viability.