Investigation into the pyrolysis behavior of chestnut shells employing Gaussian deconvolution technique

Due to the inherent complexity of biomass composition, its pyrolysis process is typically accompanied by multiple concurrent reactions. To elucidate the pyrolysis behavior of biomass and furnish scientific guidance for its efficient utilization, an extensive examination of the pyrolysis characteristics of chestnut shells over a temperature span from 303 K to 1173 K under a nitrogen atmosphere at different heating rates was conducted in the present research. By employing Gaussian deconvolution, the pyrolysis curve of chestnut shells was divided into pseudo-hemicellulose, pseudo-cellulose, and pseudo-lignin. For each of these components, the kinetic parameters have undergone validity verification via multiple model-free methods. The analysis indicated that the mean activation energy values generally followed the sequence of pseudo-lignin > pseudo-cellulose > pseudo-hemicellulose. The pyrolysis reaction mechanisms were further identified through the Coats-Redfern method. Results indicated that the chemical reaction order model (F3) predominantly describes the pyrolysis behavior of pseudo-hemicellulose, whereas the diffusion-controlled model (D3) is mainly associated with the pyrolysis of pseudo-cellulose. For pseudo-lignin, the primary reaction mechanism corresponds to random nucleation (A1/4). Additionally, thermodynamic parameters for the three pseudo-components were calculated, along with the kinetic compensation effect. Thermodynamic evaluation verified that the decomposition of chestnut shells was an endothermic and non-spontaneous process, which could be effectively converted into a value-added energy source through pyrolysis. The approach proposed in this study provides a reliable method for interpreting experimental data independent of pyrolysis behavior, which not only offers meaningful insights for the efficient resource utilization of chestnut shells but also serves as a valuable reference for optimizing the resource recovery of other lignocellulosic biomass with analogous structural and compositional properties.