Thermogravimetric analysis and kinetics characteristics of typical grains

We investigated the thermal decomposition behaviors of two typical grains, rice and corn, using a thermogravimetric analyzer at different heating rates. The pyrolysis process of rice and corn both can be divided into three stages, and the most possible pyrolysis mechanism of both rice and corn during devolatilization is a three-dimensional diffusion reaction, which can be represented by the Zhuravlev equation (G(alpha) = [(1 - alpha)((-1/3)) - 1](2)). Corn had a higher initial degradation temperature and end temperature as well as a higher mass loss in the second stage than rice. The averageE(a)of rice determined by Kissinger, FWO and Friedman method was 143.6 kJ mol(-1), 161.6 kJ mol(-1)and 148.7 kJ mol(-1), respectively. The averageE(a)of corn determined by Kissinger, FWO and Friedman method was 166.1 kJ mol(-1), 146.3 kJ mol(-1)and 170.4 kJ mol(-1), respectively. A lowerE(a)of rice than corn also indicates that rice is easier to be pyrolyzed. The predicted values using the kinetic parameters calculated show a good agreement with the experimental data at all the four heating rates. The results presented herein could provide guidance for storage of grains.

Automated summary

The thermal decomposition behaviors of rice and corn were investigated, revealing that corn has higher initial degradation and end temperatures as well as greater mass loss compared to rice. The lower average activation energy (Ea) of rice compared to corn indicates that rice is easier to pyrolyze. The predicted values using kinetic parameters show good agreement with experimental data.