Antioxidant effect of 2–4 xylenol on fuel oxidation in liquid and gas phase over a wide temperature range

Abstract

The inhibiting effect on fuel ageing of 2,4-xylenol, a phenolic antioxidant that can be produced from biomass, was investigated experimentally in the liquid phase, while its impact on combustion was studied in the gas phase. The antioxidant effect of 2,4-xylenol in liquid phase has been examined in n-decane and in a surrogate, containing 65%vol. toluene and 35%vol. n-heptane. Experiments were performed in a PetroOxy at initial oxygen pressure 7 bar and temperature held at 180 °C. The impact of 2,4-xylenol on the gas-phase reactivity of the surrogate fuel was investigated on ignition delay times and laminar flame velocities. Ignition delay times were measured in the rapid compression machine at 10 bar, from 675 to 1000 K at two equivalence ratios, 0.5 and 1. Laminar flame velocity measurements were conducted in a heat flux burner at atmospheric pressure and an initial temperature of 398 K. For all experiments considered in this work, the doping level of 2,4-xylenol was kept below 1%mol. Results are compared to effect of other usual additives, EHN and ferrocene. Results show that 2,4-xylenol exhibits a remarkable antioxidant effect in liquid phase, without affecting the main combustion characteristics of the fuel.