Combustion characteristics and kinetic analysis for pyrolysis char of torrefied pretreament from camellia shell

In this study, the combustion experiments were carried out in a simultaneous thermogravimetric analyzer and in an oxidizing atmosphere at four heating rates of 5, 10, 15, and 20 °C/min, respectively. The thermal decomposition kinetics of pyrolysis char of torrefied treatment (T-P-char) from camellia shell were invested by the isoconversional methods of Friedman and Ozawa. The results showed that the correlation coefficients of the experiment data fitting were all over 0.99, and both the average values of activation energy and pre-exponential from Ozawa were higher than those of Friedman method. The enthalpy analysis indicated that the energy difference between the activated complex and the reagent was consistent with activation energy. The Gibbs free energy changed from 185.08 kJ/mol to 204.87 kJ/mol, and the entropy changes were negative, implying that the disorder degree of the products was lower than that of the initial reactants. Moreover, the reaction mechanism transformed from the random nucleation and growth reaction to the n th order reaction when the pyrolysis temperature exceeded 450 °C.