Performance, emissions and exergy analyses of adding CNTs to various biodiesel feedstocks 

M.S. Gad ^a, Mostafa M. Abdel Aziz ^b, Hatem Kayed ^c,*

a. Mechanical Engineering Department, Faculty of Engineering, Fayoum University, Egypt
         b. Mechanical Engineering Department, Institute of Aviation Engineering and Technology, Giza, Egypt
         c. Mechanical Power Engineering Department, Faculty of Engineering, Cairo University, 12613, Egypt

Abstract: Extraction of biodiesel from waste cooking oil, jatropha, and corn oils is done by transesterification. Diesel and biodiesel were blended at 20% volume ratio to make methyl ester. At doses of 25, 50, and 100 mg/l, carbon nanotubes (CNTs) was mixed with biodiesel blend. The objective of the present research is to examine experimentally a diesel engine performance, combustion characteristics, exergy and emissions analyses with inclusion of nano additive to various methyl ester feedstocks. Methyl ester blend is enriched with CNTs as JB20C100, WB20C100 and CB20C100 where the improvements in thermal efficiency are raised about biodiesel mixture by 9%, 13% and 15%, respectively. Addition of 100 ppm of CNTs to biodiesel blends achieves the greatest reductions in CO (14%, 22% and 30%), HC (16%, 20% and 25%), and smoke emissions (15%, 19% and 23%) for JB20C100, WB20C100 and CB20C100, respectively. By comparing with B20, blending 100 ppm CNTs with JB20, CB20, and WB20 obtained the highest increases in cylinder pressure of 3%, 5%, and 10%, as well as the highest increases in heat release of 4%, 7%, and 11%, respectively. The downside of CNTs addition achieves a rise in NOx emissions by 10%, 17%, and 22% for JB20C100, WB20C100, and CB20C100, respectively. Exergetic efficiency increases by 8%, 19%, and 24% for B20T100, B20A100, and B20C100, respectively. Sustainability index improvements achieve 1.5%, 5% and 6.5%, for B20T100, B20A100, and B20C100, respectively. WB20 with CNTs of 100 ppm is highly recommended for improving engine performance, combustion, and exergy characteristics with considerable emissions reduction.

Keywords: Biodiesel; carbon nanotubes (CNTs); Engine performance; Exergy; Combustion characteristics; Emissions

https://doi.org/10.1016/j.jppr.2022.09.003