Thermogravimetric Evaluation and Kinetic Study of Pyrolysis in Most Commercialized Timber Species in the Southern Macro Region of Peru

This study investigates the pyrolysis kinetics of four timber species widely available in the southern region of Peru: Tornillo (Cedrelinga catenaeformis), Bolaina (Guazuma crinita), Zapote (Matisia Cordata), and Pashaco (Schizolobium amazonicum). The characterization was carried out through elemental analysis, the determination of the caloric power, and finding the kinetic triplet: activation energy, pre-exponential factor, and reaction order. For this purpose, a thermogravimetric analysis was implemented with four heating rates (5, 10, 20, and 40 K/min). The determination of the activation energy and the pre-exponential factor was performed using the integral isoconversional methods called by their acronyms: KAS (Kissinger–Akahira–Sunose) and OFW (Ozawa–Flynn–Wall), while JMAK (Johnson–Mehl–Avrami–Kolmogorov) kinetics. Transformations were used to determine the reaction order. Analysis of the thermal degradation profiles using the KAS and OFW methods revealed that, in the conversion range 0.1≤α≤0.8, the average activation energy for Tornillo timber is 218.7 kJ/mol, for Zapote, 154.5 kJ/mol, for Bolaina, 166.8 kJ/mol, and for Pashaco, 181.6 kJ/mol. A positive correlation was observed between the activation energy of the studied timbers and their respective density and carbon elemental composition percentages. Conversely, activation energy values were found to increase with the degree of conversion. The higher activation energy values suggest that the pyrolysis reaction proceeds slower in Tornillo and Pashaco timbers.