The thermal decomposition of wood chips (pine and beech samples) and an energy crop (thistle) is studied using thermogravimetric analysis. Assuming the addition of three independent parallel reactions, corresponding to three pseudocomponents linked to the hemicellulose, cellulose, and lignin, the weight loss associated with the pyrolysis process is simulated. The kinetic constants are based on the assumption of an irreversible, single-step, first-order process for each pseudocomponent, except for the third pseudocomponent, for which a kinetic model of third order is applied. The weight loss evolution simulated by means of the summative model has been compared with the experimental data. This summative nth-order model has been able to reproduce the experimental results satisfactorily and has evidenced the influence of the biomass composition on the pyrolysis process.

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The thermal behaviors during the pyrolysis of two different biomass samples, beech wood from carpentry residuals and artichoke thistle from energy-dedicated crops, were investigated. Thermogravimetry/differential scanning calorimetry (TG-DSC) and thermogravimetry coupled to Fourier transform infrared (TG-FTIR) analysis of evolving products were used to investigate the thermal effects of the pyrolysis process. The role of pretreatments (hot-water washing, ethanol extraction, and their combination) was also analyzed. High alterations in the heat demand were observed as a function of the initial sample mass and pyrolysis conditions. The role of vapor-solid secondary interactions was evidenced by the evolution profiles of the main pyrolysis products.

The devolatilization behavior of pine and beech wood from carpentry residues and an herbaceous product from an energy plantation (artichoke thistle) was investigated by thermogravimetry. The effect of three pretreatments, hot-water washing, ethanol extraction, and a combination, were also studied. Various approaches based on first and nth order partial reactions in a summative model of pseudocomponents were employed to determine the best kinetic parameters that describe the experiments both at linear and stepwise heating programs. The assumption of four partial reactions appropriately described the global decomposition of most of the samples, while a low-temperature partial reaction was needed for the untreated pine. After the separate kinetic parameters for each of the samples were determined, a further check on the effects of the pretreatments was carried out by determining how a common set of activation energies describes the untreated and pretreated samples of the same feedstock.