Circular Economy Strategies: Converting Food and Plastic Waste into Engine Fuels and Emission Assessments

This comprehensive study embarks on an innovative pathway to energy sustainability by integrating anaerobic digestion and plastic pyrolysis, employing fly ash as a pivotal catalyst. It meticulously examines the transformation of food and plastic waste into a viable energy source. Delving into the core of waste conversion, the research showcases a significant breakthrough in waste plastic oil (WPO) production, with an impressive 53.2% yield of liquid oil facilitated by the catalytic prowess of fly ash. This yield, underscored by a marked reduction in the requisite temperatures for pyrolysis, positions fly-ash as an economically viable and environmentally friendly catalyst. The process underscores a scalable, sustainable waste-to-energy model, advocating for further refinement and optimization for broader application. Analytical scrutiny employing scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) affirms the chemical integrity of fly ash post-LLDPE degradation, unveiling its unchanged composition and reinforcing its role in sustainable plastic breakdown. The chemical analysis reveals an intriguing predominance of alkenes, along with a notable decrease in unsaturation within the resultant oil, hinting at intricate molecular interplay during pyrolysis. Furthermore, the resultant plastic cover oil not only exhibits an elevated calorific value of 44.3 MJ/kg, surpassing that of conventional diesel, but also demonstrates enhanced combustion properties. This includes a higher heat release rate and peak cylinder pressure, along with improved brake thermal efficiency, redaction in smoke and HC, signaling its potential as an advanced diesel substitute. Despite its commendable performance, the oil's higher NOx emissions present a challenge, necessitating strategies for NOx mitigation.