Molecular Characterization of Waste Tire Pyrolysis Oil: ¹⁴C Distribution and Potential for Sustainable Fuels and Chemicals

In-depth insight into the distribution and molecular composition of biocarbon (Bio-C) content in waste is crucial for effectively converting waste into valuable resources. Bio-C distribution in raw materials and primary carbon-containing resource products within waste tire recycling plants were examined. Bio-C predominantly migrates into waste tire pyrolysis oil (WTPO), which constitutes the largest proportion of the production. Industrial-grade WTPO with a Bio-C content of 72% was distilled according to the boiling range in this study, and the saturate, aromatic, resin, and asphaltene (SARA) separation of the whole fraction was attempted. The Bio-C contents of four fractions of WTPO (initial boiling point–140 °C, 140–240 °C, 240–350 °C, and 350–final boiling point °C) were 78, 80, 76, and 62%, respectively. A distillation range similar to that of jet fuel possessed the highest Bio-C content. Furthermore, a significant portion of the Bio-C content was concentrated within the distillation ranges of conventional gasoline, kerosene, and diesel, indicating its potential for future applications as a sustainable fuel. The calculated Bio-C content of aromatic components in the light fraction of WTPO was as high as 87%. The substantial Bio-C content positions these fractions of WTPO as potential feedstocks for biobased high-value-added chemicals as well as for further separation processes. In WTPO’s heavy fraction, the Bio-C contents of SARA separated components accounted for 68, 66, 4, and 6%, respectively. The Bio-C content of WTPO was mainly concentrated in olefins and aromatics with a low carbon number and low double bond equivalent. This study preliminarily explores a value assessment analysis scheme for the pyrolysis oil derived from the complete distillation segment produced by waste refineries, providing a reference for the initial analysis strategy aimed at the high-value utilization of waste.