Feasibility assessment of bioethanol-castor oil blends (CASAHOL) as sustainable marine engine fuel: balancing performance and emissions

Abstract This research investigates the viability of bioethanol (BE)-castor oil (CO) mixtures (CASAHOL) as an alternative fuel for marine engines, specifically targeting a dual-cylinder, four-stroke, naturally aspired (carburetor) engine. The study seeks to reduce the ecological consequences of fossil fuels by exploring renewable fuel alternatives. Four fuel blends with differing bioethanol and castor oil ratios were evaluated to determine their impact on engine performance, emissions, and fuel characteristics. Experimental results indicate that the 96%BE-4%CO blend attains the best thermal efficiency (24.27%) and produces a power output of 10.7 kW at max speed, establishing it as a formidable alternative to conventional fuels. Nonetheless, it generates comparatively elevated CO 2 (10.5% vol) and NOx emissions (1164 ppm at 2000 RPM), signifying a compromise between performance and pollution. Conversely, the 99%BE-1%CO mixture exhibits the lowest NOx emissions (165 ppm at 1000 RPM), although demonstrates inferior thermal efficiency and power production. The research underscores the necessity to refine fuel mixtures to achieve a balance among efficiency, performance, and ecological consequences. The 96% BE-4% CO blend presents a feasible solution, enhancing engine performance while maintaining acceptable emission standards. Additional research is advised to enhance these blends and investigate additions that may diminish the recorded emission levels.