Tucumã Endocarp Pyrolysis Kinetics : A Comparative Analysis between Independent Parallel and Consecutive Reactions Schemes

This study investigates the thermal decomposition kinetics of tucumã endocarp pyrolysis by non-isothermal thermogravimetric analysis in a nitrogen atmosphere applying global (isoconversional methods) and multiple reactions model. The experiments were conducted using a particle diameter of 0.13 mm and three heating rates (2.5, 5.0 and 10 oC/min). Thermal decomposition stages were outlined according to each reaction model. The differential method (Friedman), integral (Ozawa-Flynn-Wall/modified Coats Redfern), and advanced (Vyazovkin) were used for an initial guess of activation energies (190.83-272.07 kJ/mol, 0.05<0.85). The kinetic triplets of independent parallel and consecutive reactions schemes were obtained considering three first-order reactions, activation energies of 39.89-168.42 kJ/mol and 39.99-152.65 kJ/mol, and pre-exponential factor logarithms of -0.41-11.84 1/s and -0.41-10.46 1/s, respectively, as well as volatilization fractions of 0.22-0.43 for IPRS and stoichiometric constants of 0.01-1.00 for CRS. Finally, the theoretical conversions and conversion rates were akin to experimental data, providing average deviations <5.0% between 150-900 °C