Application of distributed activation energy model and Coats-Redfern integration method in the study of industrial lignin pyrolysis kinetics

This study addressed the kinetics characteristics and pyrolysis behavior of waste industrial lignin in a thermogravimetric analyzer. DAEM and Coats-Redfern integration methods were employed to evaluate the kinetic parameters at varying heating rates (10–30 °C/min). The physicochemical inspection showed that the industrial lignin had excellent prospects to produce finest chemicals. The TGA results illustrated that the pyrolysis process of industrial lignin could be divided into three stages, including the water loss stage, massive decomposition stage (255–376℃), and charring stage (392–508℃). The activation energies calculated by DAEM are 12.7–23.9 kJ/mol as V/V* rose and 21–27 kJ/mol by the Coats-Redfern integration method of different pyrolysis stages. In addition, the average activation energy of the massive decomposition stage was higher than that of the charring stage. The similar activation energies calculated by both DAEM and Coats-Redfern methods confirmed the accuracy of the kinetic calculations.