Pyrolysis of waste materials using TGA-MS and TGA-FTIR as complementary characterisation techniques

Pyrolysis of waste materials, biomass wood waste, waste tyre, refuse derived fuel (RDF) and waste plastic was performed using two thermogravimetric analysers (TGA). One TGA was coupled to a mass spectrometer (MS) and the other to an infrared spectrometer (FTIR). The kinetic parameters of the pyrolysed waste materials obtained for TGA-MS and TGA-FTIR were compared using a model based on first-order reactions with a distribution of the activation energies. A further comparison of the volatile species evolved by thermal degradation (TGA) and the subsequent characterisation by the MS and FTIR spectra was performed. The first-order reaction pathways and subsequent activation energies calculated from the differential TGA data presented good repeatability between the TGA-MS and TGA-FTIR. The TGA-MS and TGA-FTIR produced a broad spectrum of qualitative data characterising the volatile gaseous fraction of the waste materials pyrolysed. TGA-MS and TGA-FTIR are shown to be valuable techniques in corroborating the respective thermograms and spectrograms of the volatile species evolved during the pyrolysis of waste materials. However both techniques are prone to interference and careful interpretation of the spectra produced is required.