This study describes the extraction of energy from waste plastics via the pyrolysis process and its optimization for efficient combustion with cleaner exhaust using water and a cetane enhancer. Water emulsion with cetane improver in waste plastic oil (WPO) was first proposed in this study, and a response surface methodology (RSM) tool was used to optimise the individual parameters. Fourier Transform Infrared (FTIR) spectra were used to characterise the WPO, and ASTM standards were used to evaluate its properties. To enhance the fuel qualities, performance, and emission characteristics, water and Diethyl ether (DEE) were added to WPO. Since the WPO, water, and DEE had their pros and cons on overall engine performance and emissions as a whole, the optimal level of individual parameters was crucial in this field. The process parameters combinations were selected based on the Box-Behnken design, and the experiments were conducted in a stationary diesel engine. The experimental results indicate that the WPO yield rate during the pyrolysis process is 43.93%, and the C-H bonds have the maximum contribution to the WPO yield rate. The result of the optimization indicates that the proposed RSM model is highly robust, and the coefficient of determination is closer to one. The optimal concentrations of WPO, water, and DEE in conventional diesel fuel for efficient and environmentally friendly production are 15.001%, 12.166%, and 2.037%, respectively. The confirmation test indicates that the predicted and experimental values under optimal conditions are in good agreement, and the aggregate demand for fossil fuel has decreased by 28.2%.
