This paper presents a systematic thermogravimetric (TG) study on the kinetics of end-of-life tyre (ELT) pyrolysis. In the experimental part of this work, TG results are compared for tyre samples of different mass and size. This shows that the conduction resistance in the milligram scale (up to ~100 mg) tyre sample can be neglected. A comparison of experimental results demonstrates that the characteristic maxima on the DTG curve (the first derivative of TG signal) shift towards higher temperatures for higher heating rates. This phenomenon is explained to have kinetic origin and it is not caused by the internal heat transfer resistance. In the modelling part of this work, the kinetic parameters of the Three-Component Simulation Model (TCSM) are calculated and compared to the literature values. Testing of the kinetic model is carried out using experiments with a varying heating rate. This shows the limitation of the simplified kinetic approach and the appropriate selection method of the kinetic parameters.

Wasted tires are the great source of fuel and valuable components but could be a cause of environmental and land pollution. This study shows the detailed method for the determination of radiocarbon isotope (14C) concentration in tires and their pyrolysis products. Samples are taken from truck and passenger car tires in the form of shredded rubber, pyrolysis oil and recovered carbon black. Liquid scintillation counting (LSC) and accelerator mass spectrometry (AMS) techniques were used for the investigation at Gliwice Radiocarbon and Mass Spectrometry Laboratory, and National Laboratory for Age Determination, Trondheim, Norway. The results are in good agreement. Radiocarbon concentration of the rubber varies significantly because of its complex structure and composition within the tires. The 14C concentration values were found to be higher in pyrolytic oil compared to rubber, and greater in truck tires rather than car tires.