Thermogravimetric analyses and kinetic modeling of three Cameroonian biomass

Abstract

Pyrolysis and combustion processes of three Cameroonian biomass have been performed in a thermobalance to determine their thermal degradation profiles and the associated kinetic parameters. The samples were heated from ambient temperature to $$900\,{{}^\circ }{\hbox {C}}$$ under four low temperature rates (5, 10, 15 and $$20\, {{}^\circ }{\hbox {C}}\,\hbox {min}^{-1}$$ ) and under non-oxidative (nitrogen) or oxidative (synthetic air) atmospheres. The kinetic parameters associated with the pyrolysis of the different samples have been estimated either using a differential isoconversional method with two reaction functions or through the extended independent parallel reaction (EIPR) model and these sets of values are compared. Under nitrogen, the mean values of the activation energies obtained using a differential isoconversional method with Mampel’s reaction function are found equal to $$121.2\,{\hbox {kJ}}\,\hbox {mol}^{-1}$$ for oil palm kernel samples, to $$158.8\,{\hbox {kJ}}\,\hbox {mol}^{-1}$$ for movingui samples and to $$172.5\,{\hbox {kJ}}\,\hbox {mol}^{-1}$$ for padouk samples. When using the 3D diffusion function, the mean value of the activation energies is the same for the two first samples and increases to $$178.8\,{\hbox {kJ}}\,\hbox {mol}^{-1}$$ for padouk samples. When applying the EIPR model, the activation energies of the cellulose part (the main part of these lignocellulosic biomass) of the samples are, respectively, equal to 142.5, 155.2 and $$149.0\,{\hbox {kJ}}\,\hbox {mol}^{-1}$$ and do not highly vary with the applied temperature ramp. Under air, the values of the kinetic parameters have been determined using the EIPR model and the values of the activation energies slightly vary with the temperature ramp for the three samples.