Mechanistic insights into co-pyrolysis of waste tires and waste lubricating oil: Kinetics and thermal behavior study

The co-pyrolysis of waste tires (WT) with waste lubricating oil (WLO) can significantly improve the quality of products. The co-pyrolysis behavior of WT and WLO was investigated by using thermogravimetric analyzer. Three isoconversional methods, Flynn–Wall–Ozawa, Friedman and Kissinger–Akahira–Sunose, were used to calculate the activation energy of the mixture at the heating rates of 5, 10, 15, and 20K/min. The obtained data were used to determine the kinetic model and thermodynamic parameters. The results showed that WLO promoted the pyrolysis of WT. The synergistic effect was shown in the reduction of the activation energy of the mixture by 10%. The mean activation energy of the main decomposition stage is 90.8 kJ/mol. Moreover, the thermodynamic stability of reaction was determined by the calculation of change in entropy, Gibbs free energy, and enthalpy. The value of pre-exponential factor is 2.48 × 107/min, which means that the co-pyrolysis reaction is not a complex interface reaction. Among all the models, the 3D diffusion model best fits the co-pyrolysis mechanism judging by Malek master plot method. The reaction function was also determined. This study will provide basic knowledge into the co-processing of WT and WLO for predicting the performance of reactor and simulating the process.