Thermal degradation of peeled cotton stalk with thermogravimetry/fourier transform infrared analysis and shuffled complex evolution algorithm

Cotton is one of the most important crops globally and is widely planted. This study systematically investigated the pyrolysis characteristics and product distribution of peeled cotton stalks using thermogravimetry/Fourier transform infrared analysis (TG-FTIR) at heating rates ranging from 5 to 60 K/min. Kinetic parameters were estimated using the two model-free methods, and the results revealed that the activation energy for pyrolysis varied between 182.97 and 213.11 kJ/mol. The three-component parallel reaction model, combined with the Shuffled Complex Evolution algorithm, was applied to perform inverse modeling of the experimental data. The corresponding exact kinetic parameters for independent hemicellulose, cellulose and lignin were obtained. The results revealed that the predicted values based on the optimized kinetic parameters were in good agreement with the experimental data. Ultimately, the blind prediction of the experimental curves at extra heating rates further confirmed the precision and suitability of the optimized kinetic parameters. The FTIR analysis indicated that the absorption spectra related to the peaks remained largely consistent at various heating rates. The evolution patterns of the gas components aligned with the trends observed in the derivative thermogravimetric curves, with the produced gases in the following order: CO₂, formaldehyde, methanol, CO, and finally methane.