Comparison study on pyrolysis characteristics and kinetics of corn stover and its digestate by TG-FTIR

Abstract

The pyrolysis potential of corn stover digestate (CSD) was compared with corn stover (CS). The effects of anaerobic digestion (AD) on pyrolysis were investigated at different rates by a thermogravimetric analyzer coupled with Fourier transform infrared spectrometry (TGFTIR). The distributed activation energy model (DAEM) was used to show the differences in the kinetics. The results indicated that the AD process improved the thermal stability with lower mean reactivity (RM), higher solid residue (S850), and decreased release of observed gaseous productions, except for CH4. The release of CH4 from CSD was higher than that of CS, especially in the temperature range of 430 °C to 520 °C. The activation energies (E) of CS and CSD were 184 kJ/mol to 293 kJ/mol (conversions were 0.1 to 0.8) and 99 kJ/mol to 331 kJ/mol (conversions were 0.1 to 0.9), respectively. The activation energies decreased after AD at the same conversion level. The calculated TG data of CS and CSD from the kinetic parameters were in good agreement with the experimental curves.