Thermogravimetric pyrolysis kinetics study of tobacco stem via multicomponent kinetic modeling, Asym2sig deconvolution and combined kinetics

Tobacco stems (TS) are tobacco residues produced, whereby the assessment of the pyrolysis kinetics of TS is critical to realize high-value utilization of agricultural residues. Firstly, a thermogravimetric analyzer was employed to perform the non-isothermal pyrolysis of TS at various heating rates. Then, the deconvolution function by Asym2sig showed that the pyrolysis of TS can be accurately modeled for three parallel decomposition fractions. Furthermore, the pyrolysis product was analyzed using fourier transform infrared spectrometer (FTIR). The results showed that the average activation energy evaluated by the isoconversion methods exhibited the highest average activation energy of 191.762 kJ·mol−1 for lignin (LG), followed by 189.268 kJ·mol−1 for cellulose (CL) and then 176.357 kJ·mol−1 for hemicellulose (HC). Based on the experimental results, the pre-exponential factors and reaction models for HC, CL and LG were also calculated and developed separately. From thermodynamic standpoint, raw materials for bioenergy generation can be derived from TS.