Feasibility analysis of replacing benzene in gasoline with cyclohexane: Engine performance and emissions

Abstract

Benzene is highly toxic, and many countries are constantly updating their gasoline regulation to limit it further. It has been proven that cyclohexane can promote the generation of hydroxyl radicals and increase combustion velocity by dynamic coupling with aromatics. This paper aims to investigate the feasibility of replacing benzene in gasoline with cyclohexane, providing suggestions for researchers. The performance and emissions of pure gasoline, cyclohexane fuel, and trimethylbenzene fuel were investigated, and the fuel economy that affects market promotion was a priority consideration. Then, the combustion parameters, sensitive to brake specific fuel consumption, were analyzed based on the sensitivity analysis method. The results show that the power performance of cyclohexane fuel is not so different from pure gasoline and only about 3.7 % lower than 15 % trimethylbenzene fuel at 2600 rev/min. At 1800 rev/min, cyclohexane fuel has the lowest carbon monoxide emission, which is about 47.37 % lower than 15 % trimethylbenzene fuel; total hydrocarbon emissions are close to pure gasoline and about 8.32 % lower than 15 % trimethylbenzene fuel; nitrogen oxide emissions are slightly higher than pure gasoline and about 6.65 % higher than 15 % trimethylbenzene fuel. Cyclohexane fuel shows higher fuel efficiency with about 1 % economic cost savings, which is favorable for market promotion. Combustion parameters sensitive to brake specific fuel consumption are crank angle of 5 %, 50 %, and 90 % heat release and peak combustion pressure. Higher peak combustion pressure and shorter combustion duration of cyclohexane fuel due to the dynamic coupling effect of cyclohexane with aromatics enhances the combustion quality in gasoline engines and makes it possible for cyclohexane to replace benzene in gasoline.