Pyrolysis of mixed municipal solid waste: characterisation, interaction effect and kinetic modelling using the thermogravimetric approach

Mixed municipal solid waste, consisting of ten major components such as yard waste, food waste, textile, paper, rubber, low-density polyethylene, high-density polyethylene, polypropylene, poly-(ethylene terephthalate) and polystyrene, is studied for performing thermal pyrolysis. Thermogravimetric analysis is utilised to quantify the interactions amongst these components, and also to compute the kinetic parameters of mixed municipal solid waste pyrolysis. The change in kinetic parameters, which is caused by interaction between components, has also been modelled. The calculated ratio of activation energy to the logarithm of the pre-exponential factor (E/logA) predicts the change in stability of the compounds during pyrolysis. For pyrolysis of individual compounds, the pyrolytic range of compounds is found to be 170–490 °C, with E/logA ranges between 10.54 and 13.9. However, considering all the binary interactions and the complex municipal solid waste matrix, the temperature range of pyrolysis expands to 170–520 °C, with stability ranges varying from 9.98 to 15.32. Furthermore, overlap ratio is calculated to quantify the intensity of these interactions. Rubber is found to cause maximum interactions which impose a negative synergistic effect on the pyrolytic decomposition behaviours of biomass and plastic mixtures, resulting in an overlap ratio of 0.9 and 0.95, respectively, for these mixtures.