Tucumã endocarp pyrolysis kinetics: A comparative analysis between independent parallel and consecutive reactions schemes

Abstract

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 °C/min). Thermal decomposition stages were outlined according to each reaction model. The differential (Friedman), integral (Ozawa-Flynn-Wall/modified Coats Redfern) and advanced (Vyazovkin) methods were used for an initial guess of activation energies (190.83–272.07 kJ/mol, 0.05 < α < 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 and 900 °C.