## 3 Results and Discussion  
Due to their abundance and availability, woody biomass is promising for the production of carbon-neutral energy. Sawdust or wood shavings are a cheap lignocellulosic compound. Sawdust as industrial and agricultural waste finds many applications in vast areas [33]. Sawdust or wood waste mainly consists of cellulose (45-50%), lignin (23-30%), hemicellulose (20-30%), and other substances (acids, soluble sugar, resins, wax, and oil) [34; 35]. Sawdust has good mechanical stability, high porosity and water-holding capacity, and sufficiently high carbon content and calorific value [36]. The main properties of the sawdust used are given in Table 2.  
Table 3 shows the maximum concentrations of the gas mixture components recorded in the experimental sets. It was found that the peak concentrations of the pyrolysis gas increased with increasing magnetron power. The maximum values were recorded at a microwave power of 2200 W, and the minimum peaks were observed at 840 W. With an increase in microwave power from 840 W to 2200 W, the maximum yield of CO increased 4 times; H\({}_{2}\), 8 times; CH\({}_{4}\), 3 times; and CO\({}_{2}\), 2 times. It is clearly seen from the quantitative data that gaseous products with a higher calorific value can be obtained at higher microwave power values. It can be assumed that increasing the power of microwave heating contributes to a deep transformation of wood macromolecules so that a higher percentage of light gases such as CH\({}_{4}\) and H\({}_{2}\) is formed. An increase in the power of microwaves provokes a more intense increase in temperature in the layer. Accordingly, the peak concentrations of gases increase. This is in good agreement with the data of earlier experimental studies [16; 17; 18; 19; 20; 21]. [PERSON] et al. [37] used kinetic models to calculate the yield of gas, tar, and char during secondary reactions of the components with an increase in temperature and heating rate during pyrolysis. Upon reaching a heating rate of 10 \({}^{\circ}\)C/min, the gas output increased and remained almost constant at temperatures above 700 \({}^{\circ}\)C. Resin yield increased below 350 \({}^{\circ}\)C. Then, the yield of pyrolysis gas decreased. Tar decomposition, which may be one of the secondary charring reactions, occurred at a temperature of about 400 \({}^{\circ}\)C. During pyrolysis, heat and mass transfer is intensified, and the initial biomass undergoes various primary and secondary conversion reactions. Primary reactions include the decomposition of cellulose, hemicellulose, and lignin present in the biomass, leading to the formation of primary and intermediate products. Intermediate products are involved in secondary cracking. Primary reactions include dehydration and charring, while secondary reactions include decomposition and volatilization of intermediates. The general trend was an increase in the average yield of pyrolysis gas components with an increase in the power of microwave irradiation (Figure 4a). However, an increase in power affected the yield of individual gases non-linearly and on a different scale. In \begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline
**Moisture (\%)** & **Ash (\%)** & **V 4 (\%)** & **High Heating** & **Fixed** & **C \({}^{d}\) (\%)** & **H \({}^{d}\) (\%)** & **N \({}^{d}\) (\%)** & **S \({}^{d}\) (\%)** & **O \({}^{d}\) (\%)** \\ \hline
6.05 & 1.4 & 81.1 & 18.2 & 11.3 & 84.7 & 2.1 & 0.3 & 2.4 & 10.4 \\ \hline \hline \end{tabular} Nomenclature: d—dry basis.  
\end{table} 
Table 2: Ultimate and proximate analysis of pine sawdust.