## 3 Results and Discussion
### Effect of Operating Conditions
#### 3.2.1 Effect of Gasifier Temperature  
The gasification temperature is a key parameter for syngas production. Figures 2 and 3 show the effect of gasifier temperature on syngas composition and SN. The gasifier temperature varies from 400 \({}^{\circ}\)C to 1200 \({}^{\circ}\)C. Low temperature conditions (from 400 \({}^{\circ}\)C to 600 \({}^{\circ}\)C) favor the production of CO\({}_{2}\) and CH\({}_{4}\). Increasing the temperature from 400 \({}^{\circ}\)C to 800 \({}^{\circ}\)C leads to a constant and significant increase in CO and H\({}_{2}\) concentrations. This phenomenon is caused by endothermic reactions like Boudouard (R-4), water gas shift (R-7), and methane steam reforming (R-8). According to [PERSON]'s principle, high temperatures favor the formation of endothermic reaction products [39]. Therefore, the CO and H\({}_{2}\) concentrations increase at high temperatures, while the CH\({}_{4}\) and CO\({}_{2}\) concentrations decrease. At high temperatures (above 800 \({}^{\circ}\)C), the concentrations of H\({}_{2}\) and CO\({}_{2}\) slightly decrease, while the concentration of carbon monoxide slightly increases. This is attributed to the water gas shift reaction (R-7). Due to its exothermic nature, this reaction is thermodynamically favored at low temperatures.  
\begin{table}
\begin{tabular}{c c c c} \hline  & **Feed** & **Outlet Stream (Industry)** & **Outlet Stream (Simulation)** \\ \hline Temperature (\({}^{\circ}\)C) & 225 & 255 & 225 \\ Pressure (bar) & 69.7 & 66.7 & 40 \\ Mass flow rate (kg/h) & 57,282.8 & 57,282.8 & 57,282.8 \\ Components flow rate (kg/h) & & & \\ CO & 10,727.9 & 4921.0 & 4068.7 \\ CO\({}_{2}\) & 23,684.2 & 18,316.4 & 19,577.3 \\ H\({}_{2}\) & 9586.5 & 8013.7 & 8063.6 \\ H\({}_{2}\)O & 108.8 & 2309.3 & 1789.9 \\ Methanol & 756.7 & 11,283.1 & 11,364.6 \\ CH\({}_{4}\) & 4333.1 & 4333.1 & 4333.1 \\ N\({}_{2}\) & 8072.0 & 8071.9 & 8072.0 \\ Ethanol & 0.6 & 8.7 & 0.6 \\ Propanol & - & 0.1 & - \\ Methyl formate & 13.0 & 25.6 & 13.0 \\ \hline \end{tabular}
\end{table}
Table 7: Comparison between simulated and industrial results of methanol yield.  
Figure 2: Effect of gasifier temperature on syngas composition.  
Figure 3 shows the effect of the gasification temperature on SN that closely determines the methanol yield. The SN value increased from a minimum of \(-\)0.49 (CO\({}_{2}\) content is greater than H\({}_{2}\)) to a maximum of 0.85 when the temperature increased from 400 \({}^{\circ}\)C to 1000 \({}^{\circ}\)C. This is because steam methane reforming (R-8) and Boudouard (R-4) reactions are dominant reactions over the water gas shift (R-7) reaction [40]. However, when the temperature increased to 1000 \({}^{\circ}\)C, the SN value dropped to 0.67. This is because of the water gas shift reaction: the carbon dioxide production being favored at high temperatures. The effects of gasifier temperature on syngas composition and SN value is closed to previous experimental results. In [PERSON] research [26], the effect on the trend of H\({}_{2}\), CO, and CO\({}_{2}\) content is the same as our simulation. The pyrolysis oil characteristics have a significant effect on the syngas composition, however, the trend of syngas SN value is the same, increasing and then decreasing.