Plastic- and tire-based alternative fuel feedstocks

The increasing deposits of plastic and tire waste offer significant environmental and energy issues, necessitating the development of sustainable conversion techniques. This study investigates the thermochemical transformation of waste high-density polyethylene and scrap tires into alternative fuels via pyrolysis, resulting in plastic pyrolysis oil (PPO) and tire pyrolysis oil (TPO). These oils were combined at 10% with standard diesel (PP10 and TP10) and tested in a single-cylinder diesel engine. Engine performance and emission parameters were tested at various speeds (1000-3500rpm). TP10 had higher brake power, peaking at 3500rpm and surpassing both diesel and PP10. TP10 had the lowest brake-specific fuel consumption across all engine speeds, demonstrating improved fuel efficiency. At 3500rpm, TP10 exhibited the greatest CO2emissions (~7%) and the lowest CO emissions (~0.06%), suggesting more thorough combustion. Because of its greater combustion temperature, TP10 produced the highest NOx emissions (~700ppm). PP10, on the contrary, performed poorly and produced more CO emissions. According to the physicochemical characterization of the fuels, PPO and TPO had heating values of 42.77 and 41.69MJ/kg, respectively, which are similar to those of diesel. These results demonstrate how waste-derived fuels may enhance engine performance while reducing harmful emissions to some extent. This approach offers a feasible route to circular waste management and sustainable energy recovery when paired with life-cycle advantages and economic viability.