Enrichment of 3rd generation biodiesel/diesel blends with optimum boron oxide for cleaner diesel emissions by multi-objective optimization using RSM

Abstract

The increasing energy prices and growing scarcity of fossil fuels have contributed to the rising popularity of biodiesel as an alternative fuel for diesel engines. The incorporation of nanoparticles (NPs) into biodiesel/diesel fuel blends significantly contributes to the reduction of emissions by enhancing fuel atomization and decreasing ignition temperatures, which in turn facilitates improved combustion efficiency. Microalgae biodiesel with boron oxide (B₂O₃) NPs has not been evaluated for diesel engine performance. The study introduced B₂O₃ NPs to biodiesel produced from transesterification of 3rd-generation spirulina microalgae oil (SMO) under 500, 1000, 1500, 2000, 2500, and 3000 W engine loads. In the tests conducted to examine the impact on engine performance and emissions, B₂O₃ was added to standard diesel/biodiesel fuel blends in concentrations of 25, 50, and 75 ppm. Then, the optimization of the experimental results was carried out using the response surface methodology (RSM). The optimal operating conditions were achieved with a 1373.68 W engine load and a 49.34 ppm NPs concentration. Under these conditions, the selected output parameters brake thermal efficiency (BTE), brake specific fuel consumption (BSFC), carbon monoxide (CO), carbon dioxide (CO₂), nitrogen oxide (NO_x), hydrocarbon (HC), and smoke were obtained as 17.99 %, 458.38 g/kWh, 0.027 %, 4.84 %, 443.99 ppm, 6.42 ppm, and 18.83 %, respectively. High R² values have indicated the accuracy of the model. As a catalyst, B₂O₃ reduces emissions and improves engine performance.