Characterization and performance evaluation of co-pyrolysis oil from waste cooking oil and waste polyethylene as a potential diesel substitute

Abstract

In this experimental study, the co-pyrolysis of waste cooking oil and waste polyethylene in different proportions was conducted at 500 °C using a fixed bed type reactor, and synthesized oils were tested to determine their physical and chemical properties, aiming to evaluate their potential as alternative fuel sources. Promising properties closely resembling those of transportation-grade diesel, such as low density (759.1–848.9 kg/m3), higher calorific value (42.33–46.22 MJ/kg), low oxygen content (1.02 %), and zero sulphur content, were observed in the obtained oils. To assess the performance, combustion, and emissions of the co-pyrolysis oil blended with diesel, three different blends (D90P10, D80P20, D70P30) were analyzed at various engine loads. The results revealed that the brake thermal efficiency of the engine increased from 26.2 % to 27.4 % for the D90P10 blend under high load conditions. At top load conditions, the blend D90P10 exhibits a maximum reduction in HC, smoke, and CO emissions by 19.3 %, 17.3 %, and 5.6 %, while NO have increased by 42.85 %. However, as the proportion of the co-pyrolysis oil in the blend increased, the NO emissions decreased. Hence, co-pyrolysis oil blending upto 30 % can be considered a potential alternative to reduce diesel consumption.