Waste Plastic Oil Utilization in Diesel Engines
Summary
Waste plastic oil derived from the thermal degradation of discarded polymers presents an emerging alternative to conventional diesel fuel. Through controlled pyrolysis, mixed or single‐type plastic waste is converted into a liquid hydrocarbon fraction whose physicochemical properties—density, viscosity and heating value—can approximate those of diesel. Blends of waste plastic oil with mineral diesel, biodiesel or oxygenated additives have been demonstrated to run effectively in compression ignition engines with minimal hardware modifications. Key performance indicators such as brake thermal efficiency and brake specific fuel consumption often approach those of pure diesel, while emission outcomes vary: carbon monoxide and particulate matter may decline due to higher intrinsic oxygen content, whereas nitrogen oxides and unburned hydrocarbons can increase without optimised combustion parameters. Advances in engine calibration, injection timing and the use of additives or higher compression ratios help to mitigate stability and emission challenges. Collectively, these developments support a circular economy approach by valorising plastic waste and reducing reliance on fossil crude.
Research from Nature Portfolio
Recent studies have investigated high‐density polyethylene–derived oil blended in quaternary mixtures with ethanol and ethoxy ethyl acetate in a single‐cylinder direct‐injection diesel engine. The inclusion of low‐viscosity, high‐oxygen‐content ethanol alongside an ester-based additive improved brake thermal efficiency by up to 5% and reduced fuel consumption by nearly 8% compared with neat diesel. Carbon monoxide and hydrocarbon emissions decreased across varying loads, while nitrogen oxide formation remained comparable to baseline operation when optimised blend ratios were employed. These findings underscore the potential of multi-component fuel systems to reconcile performance gains with emission control.
Waste Plastic Oil Utilization in Diesel Engines publication trend
The graph below shows the total number of articles in waste plastic oil utilization in diesel engines across all publications each year (not limited to Nature Index journals).
Technical terms
Pyrolysis: Thermal decomposition of organic material in an oxygen-deficient environment to produce liquid oil, gas and solid char.
Brake thermal efficiency: The proportion of fuel energy converted into useful mechanical work at the engine output shaft.
Cetane index: An empirical measure of diesel fuel ignition quality, indicating the propensity for timely combustion after injection.
Oxygenated additive: A fuel component containing oxygen atoms, added to improve combustion efficiency and reduce smoke and carbon monoxide emissions.
Net heat release rate: The instantaneous rate at which chemical energy is released during combustion, influencing pressure rise and engine performance.
References
- Characterization and Impact of Waste Plastic Oil in a Variable Compression Ratio Diesel Engine. Energies (2021).
- Influence of Advanced Injection Timing and Fuel Additive on Combustion, Performance, and Emission Characteristics of a DI Diesel Engine Running on Plastic Pyrolysis Oil. Journal of Combustion (2017).
- Energy recovery of waste plastics into diesel fuel with ethanol and ethoxy ethyl acetate additives on circular economy strategy. Scientific Reports (2022).
- Investigation in compression ignition engine performance using alternative fuels produced from waste packaging materials. Resources Conservation & Recycling Advances (2022).
- Experimental evaluation of diesel blends mixed with municipal plastic waste pyrolysis oil on performance and emission characteristics of CI engine. Case Studies in Thermal Engineering (2023).
- Sustainable energy generation from plastic waste: An in-depth review of diesel engine application. Environmental Technology & Innovation (2024).
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