PYROLYSIS OF SIBERIAN LARCH BARK
S. R. Loskutov, A. A. Aniskina, L. K. Kazaryan, O. A. Shapchenkova, E. A. Petrunina
Krasnoyarsk Science Centre of the Siberian Branch of Russian Academy of Science, V. N. Sukachev Institute of Forest, Russian Academy of Sciences, Siberian Branch, Krasnoyarsk, Russian Federation
Keywords: Siberian larch bark, pyrolysis, thermal analysis
Abstract
The aim of the work was to study the pyrolysis of Siberian larch bark ( Larix sibirica Ledeb.) as a potential raw material for the production of torrefects and biochar. Based on the results of thermogravimetry and differential thermogravimetry (DTG), the kinetics of the pyrolysis process were analysed and its thermodynamic parameters were determined. The basic measurement data were analysed: stages of mass loss during heating, temperature intervals corresponding to them and mass loss rate. Taking into account the complexity of the structure and chemical composition of bark and the related appearance of the DTG peak in the thermogravimetric test, the ‘microstages’ of bark thermal decomposition were visualized by forth derivative of the DTG contour using the Savitsky-Golei differentiating filter. The dependence of the activation energy and the pre-exponential multiplier on the degree of conversion was calculated, using the isoconversion kinetic method of Ozawa-Flynn-Wall. The average value of activation energy is 283.7 kJ/mol when the degree of thermal conversion of bark (α) changes from 0.1 to 0.8. The obtained dependence E a = f (α) was used to calculate thermodynamic parameters (Δ H , Δ G and Δ S ) and to determine the mechanism of reactions according to the Criado method characterising the bark pyrolysis process. The compensatory effect of thermodestruction was established. The mean values of Δ H , Δ G and Δ S are 294.7, 157.3, kJ/mol and 215.0 J/(mol × К), respectively. The conclusions formulate an integral evaluation of the obtained results, point out the area of their use and the subject of further research: analysis of physicochemical properties of torrefects and biochar obtained from larch bark.
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