Gasification characteristics and kinetics of corncob char with CO2 by using isothermal thermogravimetry

In order to research gasification characteristics of corncob char with CO2, the reactivity and kinetics were investigated by isothermal thermogravimetry (TG) at 800–1 000℃ with pyrolysis heating rates of 5, 40, 100℃/min. The results showed that the char reaction activity increased and the whole reaction time was relatively shortened with raising the heating rate. On the other hand, the reaction temperature had a remarkable effect on the corncob char gasification. With increasing the gasification temperature, the reaction rate speeded up distinctly and the reaction time became short evidently. Scanning electron microscopy (SEM) was employed to observe the corncob char structure. The results indicated that the faster the pyrolysis heating rate was, the bigger the hole on the char would be, and also the more abundant the pore structure was. It can be concluded that the reaction temperature has a greater influence on the gasification process than the pyrolysis heating rate. Finally, the mixed reaction model was used to calculate kinetic parameters, so the average activation energy of isothermal gasification of corncob char with CO2 was 98.7 kJ/mol and the pre-exponential factor was 519 176 min-1. The study can help to understand the reaction mechanism of biomass gaisification and provide reference for the design of gasification equipment.