## 3 Results
### Prediction of Properties of Torrefied Biomass
#### 3.4.1 Elemental Composition Prediction
\begin{table}
\begin{tabular}{c c c c c c c c c c c} \hline \hline
**Analysis** & **PREF** & **PGlobal** & **PIndividual** & **EGlobal** & **EIndividual** & **PREF** & **PGlobal** & **PIndividual** & **EGlobal** & **EIndividual** \\ \hline Temp (\({}^{\circ}\)C) & \multicolumn{6}{c}{Carbon (\%wt)} & \multicolumn{6}{c}{Hydrogen (\%wt)} \\ \hline Raw & 46.205 & 46.090 & 50.042 & 0.249 & 8.304 & 6.275 & 6.300 & 5.857 & 0.393 & 6.655 \\
250 & 49.573 & 49.951 & 51.889 & 0.763 & 4.671 & 5.715 & 5.641 & 5.334 & 1.297 & 6.674 \\
275 & 57.089 & 55.737 & 50.808 & 2.369 & 11.002 & 4.893 & 4.979 & 5.645 & 1.761 & 15.367 \\
300 & 60.127 & 62.963 & 60.352 & 4.717 & 0.375 & 4.413 & 4.357 & 4.504 & 1.264 & 2.063 \\
325 & 68.596 & 66.849 & 68.499 & 2.547 & 0.141 & 4.007 & 4.026 & 3.963 & 0.476 & 1.095 \\ \hline \multicolumn{10}{c}{Nitrogen (\%wt)} & \multicolumn{6}{c}{Oxygen (\%wt)} \\ \hline Raw & 3.612 & 3.648 & 3.589 & 0.989 & 0.650 & 43.908 & 43.963 & 40.512 & 0.124 & 7.733 \\
250 & 3.721 & 3.613 & 3.929 & 2.908 & 5.599 & 40.991 & 40.795 & 38.848 & 0.478 & 5.227 \\
275 & 3.806 & 3.952 & 3.727 & 3.842 & 2.074 & 34.212 & 35.332 & 39.820 & 3.273 & 16.392 \\
300 & 4.761 & 4.622 & 4.561 & 2.909 & 4.204 & 30.699 & 28.057 & 30.583 & 8.606 & 0.379 \\
325 & 7.922 & 4.987 & 5.015 & 37.052 & 36.693 & 22.475 & 24.139 & 22.522 & 7.402 & 0.207 \\ \hline \end{tabular}
\end{table} 
Table 5: Elemental analysis prediction results. Figure 9: Prediction curves of the dynamics of the elemental composition percentage for global parameters: (**a**) carbon, (**b**) hydrogen, (**c**) oxygen, and (**d**) nitrogen. According to Table 5, considering the initial state of the wheat straw and the four isothermal torrefaction temperatures, the results provide the following predictions: for the global parameters, there is a maximum error of 37.052% for nitrogen at a temperature of 325 \({}^{\circ}\)C, a minimum error of 0.124% for oxygen in the raw biomass, and an average error of 4.171%, with a standard deviation of 7.871%; for the individual parameters, there is a maximum error of 36.693% for hydrogen at a temperature of 275 \({}^{\circ}\)C, a minimum error of 0.141% for carbon at a temperature of 325 \({}^{\circ}\)C, and an average error of 6.775%, with a standard deviation of 8.308%, for relative errors. As can be seen, both analyses show similar results. This is expected in the case of individual parameter analysis, as it presents better fits in the weight loss curves, which directly affects the prediction of the elemental components. However, the results show that global parameter adjustment is a valid option for estimating the elemental components in wheat straw. However, in some cases, the errors obtained through global adjustments are larger than those obtained by individual adjustments. One advantage of the proposal is that with a small amount of experimental data at different temperatures, a good fit is achieved with the two-step kinetic model. In contrast, for example, in the case of global parameters, the adjustments were made in [19] with 30 data points, in [21] with 28 data points, and in [33] with 31 data points. In the case of individual parameters, the adjustments were implemented in [17] with 25 data points, in [14] with 48 data points, and in [41] with 124 data points. It was demonstrated that the prediction of a set of global parameters that satisfy the two-step kinetic model and the adjustment of the Arrhenius curves between \(-20\) to 0 dB reduces the propagation of errors.