Insights into pyrolysis and co-pyrolysis of tobacco stalk and scrap tire: Thermochemical behaviors, kinetics, and evolved gas analysis

Highlights: • It is the first time to investigate the kinetics of biomass and tire co-pyrolysis. • The synergistic effect lowered the energy input of the process. • Tobacco stalks suppressed the formation of organic gases during co-pyrolysis. • Scrap tires can interact with tobacco stalks and lower the CO₂ production. -- Abstract: In this study, the co-pyrolysis kinetics of tobacco stalk and scrap tire were investigated via thermogravimetric analyzer, while Fourier transform infrared spectrometer was used for the analysis of gas-phase products transition. The pyrolysis of tobacco stalk could be divided into three stages: moisture removal, volatile removal, and slow decomposition of residues. And there was an additional stage of the decomposition of additives for scrap tire. The positive interaction between tobacco stalk and scrap tire occurred when their ratio is 2:8, at which both differential thermal gravity peak temperatures reached a minimum of 320.5 and 390.7 °C in their corresponding regions. The size of the tire particles (from 250 μm to 3 mm) appeared to have little effect on the differential thermal gravity peak temperature of the mixtures. From the results of the kinetic analysis, the synergistic effect at multiple mixing ratios made the energy required for the co-pyrolysis process significantly lower than that of the single pyrolysis. Under the mixed conditions, the formation of organic gases and CO₂ was suppressed, the possible mechanism involved was discussed. The results obtained in this study can be used to understand the co-pyrolysis of tobacco stalk/scrap tire and provide a basis for further industrial applications.