Waste tires pyrolysis kinetics and reaction mechanisms explained by TGA and Py-GC/MS under kinetically-controlled regime

Tamara Menares; Jorge Herrera; Romina Romero; Paula Osorio; Luis E Arteaga-Pérez

doi:10.1016/j.wasman.2019.10.027

Waste tires pyrolysis kinetics and reaction mechanisms explained by TGA and Py-GC/MS under kinetically-controlled regime

Waste Manag. 2020 Feb 1:102:21-29. doi: 10.1016/j.wasman.2019.10.027. Epub 2019 Oct 22.

Authors

Tamara Menares¹, Jorge Herrera², Romina Romero³, Paula Osorio², Luis E Arteaga-Pérez⁴

Affiliations

¹ Laboratory of Thermal and Catalytic Processes (LPTC), Department of Wood Engineering, University of Bío-Bío, Concepción, Chile; Technological Development Unit, Universidad de Concepción, Coronel, Chile.
² Laboratory of Thermal and Catalytic Processes (LPTC), Department of Wood Engineering, University of Bío-Bío, Concepción, Chile.
³ Technological Development Unit, Universidad de Concepción, Coronel, Chile.
⁴ Laboratory of Thermal and Catalytic Processes (LPTC), Department of Wood Engineering, University of Bío-Bío, Concepción, Chile. Electronic address: larteaga@ubiobio.cl.

PMID: 31654876
DOI: 10.1016/j.wasman.2019.10.027

Abstract

The fast pyrolysis of waste tires (WTs) is studied by quasi-isothermal thermogravimetric (TGA) analysis, kinetic modelling and an analytical pyrolyzer coupled with gas chromatography/mass spectrometry (Py-GC/MS). The TGA demonstrated that the WTs pyrolysis is ruled by devolatilization/condensation and depropagation reactions, up to 482 °C. At higher temperatures, the cyclization and aromatization of primary products take place to form mostly monoaromatics. Py-GC/MS experiments were performed under kinetic regime according to the thermal map established by the ratio between Biot́s (31.25) and Py-numbers (7.7⋅10⁶). Limonene (51%) and isoprene (20.5%) were the major compounds detected at temperatures below 435 °C, while above 600 °C limonene was converted to mono-aromatics (S_BTX = 28.7%). The approach to equilibrium of Diels-Alder reaction demonstrated that there is an equilibrium-ruled behavior between isoprene and limonene, particularly at T > 600 °C. The E_a values calculated by the Starinḱs model ranged from 101.5 to 176.7 kJ/mol, while for model-based kinetics it was 152.7 kJ/kmol. The integration of TGA, kinetic modelling and Py-GC/MS provided insights into pyrolysis reaction mechanism.

Keywords: Kinetics; Py-GC/MS; Pyrolysis; Reaction mechanism; Waste tires.

MeSH terms

Gas Chromatography-Mass Spectrometry
Hot Temperature*
Kinetics
Pyrolysis*
Temperature