Cost-Effective Chemical Upgradation of Plastic Pyrolysis Oil for Engine Applications: Performance Evaluation as a Diesel Blend

Abstract

This study evaluates upgraded waste plastic pyrolysis oil (UWPO) as a sustainable alternative fuel to address the dual challenges of increasing energy demand and plastic waste accumulation. The novelty of this work lies in the development of an energy-efficient and cost-effective chemical upgrading strategy that enhances the fuel quality of waste plastic pyrolysis oil without relying on conventional high-pressure hydrogenation or energy-intensive refining processes, thereby improving its suitability for compression ignition engines. The upgraded oil was comprehensively characterized for key physicochemical properties, including density, gross calorific value, flash point (10 °C), fire point (14 °C), pour point (–4 °C), and viscosity (1.08 cSt), demonstrating improved fuel handling and storage characteristics. Engine performance, combustion, and emission analyses were conducted using 10% (UWPO10) and 20% (UWPO20) UWPO blends with commercial diesel. Comparative evaluation showed that commercial diesel exhibited the highest brake thermal efficiency (33.86%), whereas UWPO20 achieved 27.80%, indicating a moderate reduction in efficiency at higher blend ratios. Similarly, brake specific fuel consumption increased from 6.353 × 10–5 kg kW–1 s–1 for diesel to 7.804 × 10–5 kg kW–1 s–1 for UWPO20. However, UWPO10 exhibited the highest mechanical efficiency (92.87%), surpassing both commercial diesel (87.47%) and UWPO20 (88.59%), while both blends showed reduced air–fuel ratios, indicating improved combustion characteristics. To evaluate industrial feasibility, a techno-economic analysis of a 10 TPD waste plastic pyrolysis and oil upgrading facility was performed, demonstrating the economic viability of the proposed process with favorable production economics compared with conventional fossil-derived fuels. Overall, the study establishes chemically upgraded waste plastic pyrolysis oil as a promising diesel blending component and provides an integrated technical and economic framework for sustainable plastic waste valorization, supporting circular economy and low-carbon energy initiatives.