Performance and emission analysis of a dual-fuel engine operating on high natural gas substitution rates ignited by aqueous carbon nanoparticles-laden diesel/biodiesel emulsions

Abstract

The dual-fuel (DF) combustion process is a promising engineering solution to achieve clean combustion and high thermodynamic efficiency. The composition of pilot fuel (PF) can be considered as one of the effective parameters on the combustion quality of the DF process. In general, employing biodiesel blended fuel samples as PF can reduce brake power (BP) and increase fuel consumption. Therefore, developing fuel formulations harboring additives that are capable of boosting brake power (BP) and reducing fuel consumption of DF diesel engines (DFDEs) while also mitigating their harmful emissions, is highly considered. To this end, the present study was set to investigate emission and performance characteristics of a natural gas (NG) DFDE ignited by water-emulsified (WE) diesel/biodiesel (D/B) blends (5 vol% biodiesel and 3 wt% water) containing 30 and 60 µM aqueous carbon nanoparticle (CNP). Neat diesel and D/B blend containing 5 vol% biodiesel were used as control fuel. The engine was fueled with high NG substitution rates (50–80% of the total fuel energy) at engine loads (25–100% of full load). Overall, emissions and performance characteristics of the engine were significantly affected by engine load and NG substitution rate. On average, the WE D/B blend doped with 30 µM could provide acceptable results in terms of engine emissions and performance. This fuel formulation could mitigate unburned hydrocarbon emissions by about 8 to 40% at different loads, even though increased NOx emissions. The power generation cost of the selected fuel blend was also about 5 to 23% lower than the control fuels.