Reaction mechanism and evolved gases of larch bark pyrolysis by TG-FTIR analysis

Abstract

The reaction mechanism and evolved gases of larch bark were investigated using thermogravimetry and Fourier transform infrared spectrometry analysis at 10–50 K min−1. Larch bark pyrolysis starts at approximately 450 K. One peak and one shoulder at low heating rate were observed. This shoulder turns into another peak at higher heating rate. The average value of the final residue is approximately 24%. The average activation energy was estimated as 184.72 kJ mol−1 by the Flynn–Wall–Ozawa method and 201.24 kJ mol−1 by the Kissinger–Akahira–Sunose method, and both have a discrepancy of 8.9%. The sixth or seventh reaction model is responsible for larch bark pyrolysis. The pyrolysis of larch bark produces H2O, CO2, CH4, CO, C=O and others, most of which are released in the temperature range of 500–800 K, except that CO2 has an additional peak value at around 1200 K. In addition, cellulose is the main component in larch bark, and its quantity is larger than that of hemicellulose.