PYROLYSIS OF NEEDLES PICEA OBOVATA LEDEB.: THERMAL AND THERMODYNAMIC PARAMETERS, KINETICS, REACTION MECHANISMS

The study is devoted to an urgent problem – pyrolytic processing of woody greens (WG) of conifers, using the example of needles Picea obovata Ledeb., which makes up to 70% of the biomass of WG. The aim of the work was to determine, using the analytical system TG 209 F1 (NETZSCH, Germany), the parameters of the pyrolysis process of the post-extraction residue (PER) of needles, which are necessary to create an effective pyrolysis technology for conifers. On the basis of PER thermogravimetry data, biochar yield 24.79±1.05% (coefficient of variation 4.16%); mass loss profiles of PER; dependence of activation energy on the conversion degree using the Ozawa-Flynn-Wall (OFW) isoconversion model; thermodynamic parameters DG, DH, DS were determined. The average values of Ea, DG, DH, DS were 259.8, 158.3, 240.4 kJ/mol and 247.9 J/(mol×K), respectively. Thermal decomposition of PER proceeds by the mechanism of nucleation and the reaction controlled by the phase boundary. The results obtained are new for this type of plant raw materials and processing method and will be in demand when creating an appropriate innovative technology in the Russian Federation, where scientific developments in pyrolysis of coniferous woody greens are actually paid no attention. Previously, we investigated the chemical composition of pyrolysis liquid of pine needles PER. The market price analysis for a number of individual components indicates the expediency of studying the composition of pyrolysis liquid of pine needles PER, which is the subject of our further research based on the modern analytical system Py-GC/MS.