Comprehensive analysis of the preparation of waste frying oil biodiesel and its application characteristics in diesel engines based on recycling economic structure in South Korea

This research presents an innovative approach by addressing the underexplored application of waste frying oil (WFO) biodiesel and multi-walled carbon nanotubes (MWCNTs) as additives in multi-cylinder diesel engines. Unlike previous studies that primarily focused on traditional biodiesel sources or costly metal nano-additives, this study explores the combined use of cost-effective WFO biodiesel and MWCNTs, a combination that has not been extensively investigated in multi-cylinder diesel engines. Furthermore, the study presents novel insights into the impact of MWCNTs on greenhouse gas (GHG) emissions and smoke particle morphology, an area that has often been overlooked in previous research. The incorporation of MWCNTs in this study results in simultaneous reductions in CO, CO₂, HC, and NOx emissions, as well as an increase in engine thermal efficiency, distinguishing it from traditional fuel additives. Moreover, a comprehensive economic analysis of MWCNTs revealed a modest cost increase of only 0.17 %, underscoring their potential to deliver both environmental and economic benefits. This research fills a gap in current literature by combining WFO biodiesel and MWCNTs in a multi-cylinder diesel engine, exploring their impact on both combustion performance and emissions, while considering the economic viability of nano-additives in sustainable fuel applications.