The utilisation of oils produced from plastic waste at different pyrolysis temperatures in a DI diesel engine

Chemical recycling is an attractive way to address the explosive growth of plastic waste and disposal problems. Pyrolysis is a chemical recycling process that can convert plastics into high quality oil, which can then be utilised in internal combustion engines for power and heat generation. The aim of the present work is to evaluate the potential of using oils that have been derived from the pyrolysis of plastics at different temperatures in diesel engines. The produced oils were analysed and found to have similar properties to diesel fuel. The plastic pyrolysis oils were then tested in a four-cylinder direct injection diesel engine, and their combustion, performance and emission characteristics analysed and compared to mineral diesel. The engine was found to perform better on the pyrolysis oils at higher loads. The pyrolysis temperature had a significant effect, as the oil produced at a lower temperature presented higher brake thermal efficiency and shorter ignition delay period at all loads. This oil also produced lower NOX, UHC, CO and CO2 emissions than the oil produced at a higher temperature, although diesel emissions were lower.