Experimental evaluation of a diesel engine fuelled by pyrolysis oils produced from low-density polyethylene and ethylene-vinyl acetate plastics

Depletion of oil resources and increase in energy demand have driven the researchers to seek ways to convert the waste products into high quality oils that could replace fossil fuels. Plastic waste is in abundance and can be converted into high quality oil through the pyrolysis process. In this study, pyrolysis oils were produced from polyethylene (LDPE700), the most common used plastic, and ethylene-vinyl acetate (EVA900) at pyrolysis temperatures of 700 degrees C and 900 degrees C respectively. The oils were then tested in a four cylinder diesel engine, and the performance, combustion and emission characteristics were analysed in comparison with mineral diesel. It was found that the engine could operate on both oils without the addition of diesel. LDPE700 exhibited almost identical combustion characteristics and brake thermal efficiency to that of diesel operation, with lower NOX, CO and CO2 emissions but higher unburned hydrocarbons (UHC). On the contrary, EVA900 presented longer ignition delay period, lower efficiency (1.5-2%), higher NOX and UHC emissions and lower CO and CO2 in comparison to diesel. The addition of diesel to the EVA900 did not significantly improve the overall engine performance. (C) 2017 The Authors. Published by Elsevier B.V.