Thermal decomposition kinetics modeling of energy cane Saccharum robustum

This work aims to study the thermal decomposition kinetics of energy cane Saccharum robustwn. The experiments were carried out in a thermogravimetric analyzer at heating rates of 5, 10 and 20 degrees C/min under nitrogen atmosphere and mean particle diameter of 253.5 mu m. Three thermal decomposition stages were identified: dehydration, pyrolysis and carbonization. The activation energies were determined through three model-free methods (Friedman, Flynn-Wall-Ozawa, and Vyazovkin) varying between 107.5 and 204 kJ/mol. The master plots showed different representations of conversion functions (reaction orders from 2 to 7). The linear model fitting method validated the activation energy (177.1 kJ/mol) obtained by single-step reaction. Moreover, a multi-step method was proposed considering four independent parallel reactions (extractives, hemicellulose, cellulose, and lignin) obtaining activation energies from 60 to 181 kJ/mol, pre-exponential factor from 1.1 . 10(2) to 5.8 . 10(12) 1/s, 1st and 3rd reaction orders, and compositions from 0.12 to 0.43 with high quality of fit.