Towards Sustainable Valorization of HDPE Plastic Waste: Experimental and Numerical Evaluation of Pyrolytic Oil Atomization

The rising instability in global energy markets and fuel supply challenges in 2026 have intensified the search for sustainable alternative fuels. Since most plastics originate from petrochemical sources, they represent a valuable feedstock for energy recovery once they become waste. In this study, high-density polyethylene plastic waste was processed via pyrolysis to produce pyrolytic oil, which was characterized and compared with conventional extra-light heating oil. Evaluating the atomization performance of high-density polyethylene pyrolytic oil represents an important technical step toward assessing its potential for more sustainable plastic waste valorization and alternative heating applications. The atomization behavior of both fuels was investigated through a combined experimental and numerical approach. The spray characteristics were measured using the VISISIZE 60N droplet characterization system, enabling detailed analysis of the droplet size distribution. In parallel, CFD simulations were conducted in Ansys FLUENT using the Euler–Lagrange framework. The pressure-swirl atomizer was modeled with a Linear Instability Sheet Atomization model to describe the primary breakup, with emphasis on the influence of the model constants. The results show that the pyrolytic oil exhibits spray characteristics comparable to heating oil, with only minor differences in the droplet size distribution and breakup behavior. The CFD simulations captured the droplet size distribution trends successfully, confirming the predictive capability of the Euler–Lagrange framework. These findings indicate that pyrolytic oil is a viable alternative fuel for pressure-swirl atomization systems, contributing to both waste valorization and mitigation of the current energy challenges.