Miloš Auersvald

This study examines the upgrading of plastic waste pyrolysis oil (PWPO) derived from real waste electrical and electronic equipment (WEEE) and waste packaging (WP), with the objective of producing oil fractions for their valorization in material recycling strategies. The PWPO, rich in oxygen, nitrogen, sulfur, chlorine and bromine, was hydrotreated and subsequently fractionated into distillation cuts (naphtha, kerosene, atmospheric gas-oil and residue). The experiments were carried out in a continuous laboratory facility using two commercial hydrotreating catalysts: NiMo/Al₂O₃ and CoMo/Al₂O₃. These catalysts were tested in 5-day-long experiments, increasing the temperature by about 30 °C every 24 hours, from 240 °C to 360 °C. In general, the NiMo catalyst performed better, yielding a hydrotreated oil virtually free of halogens at 360 °C. The naphtha fraction, representing almost half of the hydrotreated oil, contained neither sulfur nor nitrogen, and a proportion of benzene, toluene, ethylbenzene, and xylenes (BTEX) around 75 wt.%, making it an alternative source of these valuable and widely used chemicals. In addition, naphthalene-rich kerosene and gas oil fractions were produced, with potential for use as a naphthalene oil source. The bottom residue fraction, yielding ≈ 20 wt.%, could be reintroduced into refinery processes or used as marine fuel. These exceptional results enable the design of circular strategies for the production of petrochemicals from waste materials.

The transition toward synthetic renewable transportation fuels requires a thorough understanding of their effects on engine behavior, especially on the engine-lubrication system. This study evaluates oil dilution and changes in oil properties through driving tests using four Ethanol-to-Gasoline (ETG) fuels with varying compositions. Commercial (Super 95) and alkylate-based gasolines were used as benchmarks. Tests included cold‑start short‑distance, cold‑start RDE‑compliant, and mixed cold–warm high‑load driving.Key findings are: (1) ETG-based fuels produced higher oil-dilution rates than reference fuels; (2) this led to reduced viscosity and flash point; (3) viscosity index and density remained stable or improved; (4) cumulation of heavy aromatics in the oil.Comprehensive oil analysis revealed a strong link between oil dilution and the presence of heavy (C10+) aromatics in ETG fuels. Modified ETG contained ~75% less C11+ aromatics, resulting in lower oil dilution than standard ETG, but still about double that of commercial gasoline. Fresh oil with added light aromatics surprisingly boosted viscosity index, although aromatics in lubricating oils are generally undesirable.These findings identified a critical gap in current gasoline specifications. Distillation criteria, designed to prevent engine oil dilution, do not capture the behavior of new synthetic fuel components. Possible solutions include tightening limits (e.g., E150), introducing new ones (e.g., E180) for distillation tests, further reducing heavy‑aromatic fractions in ETG production, or using ETG as a blend at ≤50% concentration. Overall, we showed the need for updated fuel‑quality frameworks to ensure compatibility of advanced synthetic fuels with current engine lubrication systems.