Pyrolysis characteristic and mechanism of waste tyre: A thermogravimetry-mass spectrometry analysis

In this study, waste tyre pyrolysis characteristic was investigated by a thermogravimetric analyzer combined with a mass spectrometer (MS). At the same time, the functional groups at the surface of residue char were also characterized by a Fourier-transform infrared (FTIR) spectrometer. The main components of the gas evolved from tyre pyrolysis process were H2O, CO, CO2, and hydrocarbon. According to MS and thermogravimetric (TG) curves, tyre pyrolysis could be divided into four stages. The first stage was due to water vaporization and plasticizer decomposition at the temperature below 320 °C. The secondary stage was attributed to natural rubber decomposition at 320-400 °C, and the third stage was related to the decomposition of synthetic rubber, which took place at 400-520 °C. The fourth stage was occurred above 520 °C. The variation of the functional groups on the residue char analyzed by FTIR also proved the above assumption.