Pyrolysis behavior and kinetic analysis of waste polypropylene-based complex for cable filler

To better understand the thermochemical conversion for the pyrolysis recycling of cable waste, the pyrolysis kinetics of the typical cable filler was investigated in detail. Thermogravimetric experiments were conducted at different heating rates ranging from 5 °C/min-1 to 40 °C/min-1. Three degradation stages were observed in the process of pyrolysis. The influence of air on the superposition of the first two peaks was also identified. The activation energy at different heating rates was calculated using three commonly used model-free methods. A three-component reaction scheme was proposed to describe the whole degradation process. The first one was associated with the stearic acid decomposition, the second was dominated by the polypropylene decomposition, while the third was attributed to the calcium carbonate decomposition. The created reaction model combined with an optimization algorithm was applied to determine the kinetic parameters. The values of activation energy estimated by this method were in accordance with those by isoconversional methods, which verified the accuracy of the parameter calculation by the optimization algorithm. The predicted results based on the optimized parameters agreed well with the experimental data. Finally, the whole kinetics process was deconstructed into three independent reactions corresponding to all reactants and products.