Energy, Exergy, and emissions (3E) assessment of a low-displacement engine powered by biodiesel blends of palm oil mill effluent (POME) and hydroxy gas

Abstract

In this research, an experimental assessment of a low-displacement diesel engine evaluated the influence of hydroxy gas enrichment in a biodiesel blend produced from industrial palm oil residues. The study incorporates different performance parameters from energy, exergy, combustion, and emissions criteria. The engine is monitored to operate at a constant speed of 3600 rpm and load conditions from 20% to 100%, and the fuels analyzed were commercial diesel and POME 10 biodiesel, whereas the hydroxy gas flow rates additions were set to 0.075, 0.150, and 0.225 LPM. The results of the study indicated that the presence of hydroxy gas in the POME 10 biodiesel increased the combustion pressure between 3.77 and 11.86%, while the heat release rate is intensified up to 15.61% depending on load condition. Also, hydroxy gas volumetric flow enrichment of 0.225 LPM boosted both energy and exergy efficiencies up to 15.36% and 12.15%, respectively. The emissions assessment demonstrated that hydroxy gas doping compensated the magnification of CO2 emissions produced by the POME 10 implementation. Additionally, the presence of hydroxy gas further reduces unburned hydrocarbons (HC) and smoke opacity by 11.02% and 9.39%, respectively, compared to the POME 10 standalone operation. In general, hydroxy replacement stands as a reliable and cost-effective tool to minimize the environmental pollution associated with biodiesel blends from palm oil waste residuals.