Pyrolysis kinetic evaluation by single-step for waste wood from reforestation

The objective of this study was to evaluate the kinetic parameters of pyrolysis of waste wood from reforestation: Eucalyptus benthamii (EB), Eucalyptus dunnii (ED) and Pinus elliottii (PN). The kinetic study was performed using the Friedman, Flynn-Wall-Ozawa (FWO), Kissinger-Akahira-Sunose (KAS), Starink, and Vyazovkin methods from the experimental data at four heating rates (5, 10, 20 and 30 °C min−1). The Friedman method presented higher activation energy values (Ea) when compared to the other methods (EaEB = 142.98 kJ mol−1, EaED = 147.71 kJ mol−1, EaPN = 155.46 kJ mol−1). The KAS, Starink and Vyazovkin methods resulted in approximate values of activation energy (EaEB = 132.83-133.31 kJ mol−1, EaED = 137.51-137.98 kJ mol−1, EaPN = 145.24-145.70 kJ mol−1) due to the approximation equations with lowest relative errors. The simulation of curves using the kinetic parameters obtained with the Vyazovkin method showed that the decomposition process of EB and ED occurs as a multi-step process resulting in an unsatisfactory result for the simulation. On the other hand, for PN a satisfactory fit to the experimental data was obtained, which demonstrates its suitability for application to the modeling of thermochemical systems.