Chemical recycling of end-of-life tires by intermediate pyrolysis using a twin-auger reactor: Validation in a laboratory environment

Juan Daniel Martínez, Felipe Campuzano, Andrés F. Agudelo, Natalia Cardona-Uribe, Cindy Natalia Arenas

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    21 Scopus citations

    Abstract

    This work deals with the chemical recycling of end-of-life tires (ELT) by means of intermediate pyrolysis to produce tire pyrolysis oil (TPO), raw recovered carbon black (rCB), and tire pyrolysis gas (TPG). Here, the operational features of a twin-auger pyrolyzer, as well as the characteristics of the resulting products were satisfactorily validated in a laboratory environment. Hence, the twin-auger pyrolyzer used in this work aligns with the characteristics associated with the fourth technology readiness level (TRL-4). In order to assure this statement, both the statistical repeatability of yields and, the consistency of the product's properties were assessed. As such, 27 experiments divided into 4 replicates were conducted at the conditions which maximized the TPO yield, while minimizing that of raw rCB: ELT mass flow rate of 1.16 kg/h, reactor temperature of 475 °C, solid residence time of 3.5 min, and N2 flow rate of 300 mL/min. Thereafter, we explored the main physicochemical properties of different pyrolysis product samples, randomly selected throughout the experimental campaign. The TPO was characterized in terms of density, viscosity, total acid number (TAN), flash point, elemental composition, heating value, distillation characteristics, and contents of both water and carbon Conradson. The contents of saturates, aromatics, resins, and asphaltenes (SARA) were also determined. The raw rCB was characterized by proximate, elemental, and heating value analyses. Textural properties such as surface area (SBET), total pore volume (VT), micropore volume (VMin), and mesopores volume (VMeso), were identified as well, including SEM images analysis. Finally, the chemical composition of the TPG was measured by quantitative gas chromatography (H2, CH4, CO, CO2, C2H6, C2H4, C3H8, H2S). The analysis of variance (ANOVA) suggested that the twin-auger pyrolyzer is repeatable in terms of TPO, raw rCB, and TPG yields, with a reliability of 95 %. Likewise, the characterization of the products revealed that their properties remained quite stable across the experimental runs. These results demonstrate the stability and suitability of the experimental facility, which leads to the conclusion that the twin-auger reactor is a reliable and promising technology for the chemical recycling of ELT by means of intermediate pyrolysis.

    Original languageEnglish
    Article number105298
    JournalJournal of Analytical and Applied Pyrolysis
    Volume159
    DOIs
    StatePublished - Oct 2021

    Bibliographical note

    Publisher Copyright:
    © 2021 Elsevier B.V.

    Keywords

    • Chemical recycling
    • Circular economy
    • End-of-life tires
    • Intermediate pyrolysis
    • Twin-auger

    Types Minciencias

    • Artículos de investigación con calidad A1 / Q1

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