## 3 Results and Discussion
### Results of Calorimetric and Thermogravimetric Tests  
Table 3 presents data on the percentage of ash and volatile substances in pellets produced from plant cultivation waste for industrial purposes and their calorific value. The lowest ash content-2.92% was found in pellets made of 50% tobacco stalks and 50% coniferous sawdust (P4). The highest amount of ash was recorded in the pellet composed of 100% tobacco stalk biomass (P3). In the tested pellets, the use of an admixture of coniferous sawdust reduced the ash content in the tested solid fuels--in the case of sunflower by about 14.97% (P1 and P2), tobacco by 39.92% (P3 and P4), and Jerusalem artichoke by 24.43% (P5 and P6), compared to pellets made of 100% of these materials. The highest amount of volatile compounds was recorded for the pellet consisting of 100% sunflower stalks (P1), with a value of 79.14%. The least volatile compounds were formed during the combustion of a mixture of Jerusalem artichoke and coniferous sawdust (P6) in the ratio of 50%:50%. In the case of sunflower (P2) and Jerusalem artichoke (P4) biomass pellets, the addition of coniferous sawdust reduced the amount of volatile compounds compared to pellets made of 100% of these materials (P1 and P3). On the other hand, for tobacco stalk pellets, the addition of coniferous sawdust (P4) caused an increase in the amount of volatile compounds by 1.07% compared to pellets whose 100% composition was tobacco stalk biomass (P3). The calorific value of the tested pellets ranged from 16.35 MJ\(\cdot\)kg\({}^{-1}\) to 17.70 MJ\(\cdot\)kg\({}^{-1}\) (Table 2). The addition of sawdust slightly reduced the calorific value of pellets made of sunflower biomass and tobacco (P2 and P4). In the case of topiambour biomass, the \begin{table}
\begin{tabular}{c c c c} \hline \hline
**The Type of Pellets** & \begin{tabular}{c} **Ash Content** \\ **[\%]** \\ \end{tabular} & \
\begin{tabular}{c} **Volatile Compounds** \\ **[\%]** \\ \end{tabular} &
\begin{tabular}{c} **Calorific Value** \\ **[M]\(\cdot\)kg\({}^{-1}\)**]** \\ \end{tabular} \\ \hline P1 & 4.14 \({}^{\text{b}}\)\(\pm\) 0.24 & 79.14 \({}^{\text{a}}\)\(\pm\) 0.11 & 16.72 \({}^{\text{a}}\)\(\pm\) 0.06 \\ P2 & 3.52 \({}^{\text{a}}\)\(\pm\) 0.11 & 78.35 \({}^{\text{a}}\)\(\pm\) 0.26 & 16.35 \({}^{\text{a}}\)\(\pm\) 0.04 \\ P3 & 4.86 \({}^{\text{b}}\)\(\pm\) 0.28 & 76.99 \({}^{\text{a}}\)\(\pm\) 0.17 & 17.70 \({}^{\text{a}}\)\(\pm\) 0.13 \\ P4 & 2.92 \({}^{\text{a}}\)\(\pm\) 0.19 & 78.06 \({}^{\text{b}}\)\(\pm\) 0.19 & 17.30 \({}^{\text{a}}\)\(\pm\) 0.12 \\ P5 & 4.01 \({}^{\text{b}}\)\(\pm\) 0.17 & 78.47 \({}^{\text{b}}\)\(\pm\) 0.35 & 17.21 \({}^{\text{a}}\)\(\pm\) 0.11 \\ P6 & 3.03 \({}^{\text{a}}\)\(\pm\) 0.07 & 76.54 \({}^{\text{a}}\)\(\pm\) 0.38 & 17.53 \({}^{\text{a}}\)\(\pm\) 0.17 \\ \hline \hline \end{tabular} Statistically significant differences marked by different letters (\(p\leq\) 0.05). The data were analyzed separately for each type of materials.  
\end{table} 
Table 3: Average values of ash, volatile compounds, and calorific value of the analyzed types of pellets. addition of coniferous sawdust (P6) increased the calorific value by 1.85% compared to pellets made of 100% topinambour biomass (P5).The calorific value of the waste generated during the production of sunflower seeds ranges from 13 to 17.5 MJ\(\cdot\)kg\({}^{-1}\). For the moisture content of fuels produced from this waste at the level of 9.1 to 11.6%, the ash content ranges from 1.7 to 3.8%, and the volatile substances from 70.4 to 77.1%. Waste from sunflower production has promising properties to be used as fuel for renewable energy [26]. Solid biofuels are characterized by a high content (on average, 67%) of volatile matter [27]. Test results for tobacco pellets indicate that this type of pellet has 87.75% volatile substances [28]. In turn, other scientists recorded the ash content of 14.67% for tobacco stem pellets and 64.54% of volatile compounds [29]. [PERSON] et al.