Characterization of corncob-derived biochar and pyrolysis kinetics in comparison with corn stalk and sawdust

• Characterization of corn cob was compared with corn stalk and sawdust.
• 16 reaction mechanisms were applied to deduce the corn cob pyrolysis mechanism.
• The kinetic parameters were calculated based on the best fitted mechanisms.
• The weight active energy of corn cob was lower than that of corn stalk and sawdust.

In this study, thermal and physicochemical characterization results of corncob (CC) and its derived biochars were analyzed and differentiated from sawdust (SD) and cornstalk (CS). The pyrolysis temperature shows the largest effect on the yield of biochar produced compare with residing time, heating rate, and feedstock particle size. The CC-derived biochars produced at temperatures ranging from 300 to 600 °C were analyzed. The CC was thermochemically altered to a stable biochar when the pyrolysis temperature was set to over 500 °C. To deduce the reaction mechanism of the CC during the major thermal decomposition stage, 16 mechanisms in solid-state reactions were applied. The reaction order and nucleation mechanisms described the thermal decomposition of the CC. By using the best-fitted mechanisms, the kinetic parameters were calculated. The weight active energy of the CC was 122.42 kJ/mol, which was the lowest value compared to those of CS and SD.