# Sugarcane Bagasse Torrefraction for Fluidized Bed Gasification
## 4 Results and Discussion
### Improving Energy Properties of Sugarcane Bagasse by Torrefaction  
Tables 4 and 5 summarize the obtained composition of the torrefied sugarcane bagasse at temperatures of 230 \({}^{\circ}\)C and 280 \({}^{\circ}\)C and for residence times of 30 and 45 min, respectively. Torrefaction causes reductions in biomass energy yields on an ash-free basis (DAF) [59] because of partial devolatilization but also causes an increase in the energy density (DAF). In the case of the sugarcane bagasse torrefaction at 230 \({}^{\circ}\)C (Table 4), it was noticed that by reducing 3% to 5% of the energy yields, the feedstocks lost between 18% to 19% of its original mass. Thus, it increases by 19% to 20% in the bagasse samples' energy density for those experimental conditions, increasing its higher heating value by 20%. \begin{table}
\begin{tabular}{c c c c c c c c c c} \hline  & **Present Study** & [51] & [52] & [53] & [4] & [54] & [55] & [56] & [57] \\ \hline Volatile matter (wt.\%, dry basis) & 88.48 & 87.06 & 83.0 & 85.61 & 88.7 & 82.1 & 85.43 & 79.35 & n.a. \\ Ash (wt.\%, dry basis) & 2.1 & n.a. & 4.0 & 2.44 & 2.0 & 1.6 & 1.68 & 3.66 & 6.8 \\ Fixed Carbon (wt.\%, dry basis) & 9.41 & 12.94 & 13.0 & 11.95 & 9.3 & 16.3 & 12.89 & 17.88 & n.a. \\ Higher heating value (MJ. kg\({}^{-1}\), dry basis) & 15.96 & 18.6 & 18.9 & 18.99 & 18.7 & 19.19 & 19.14 & 19.41 & 18.85 \\ \hline \end{tabular}
\end{table} 
Table 2: Proximate analysis of sugarcane bagasse sample compared with other studies (wt.%, dry basis). \begin{table}
\begin{tabular}{c c c c c c c c c c} \hline
**Element** & **Present Study** & [51] & [52] & [53] & [4] & [54] & [55] & [56] & [57] \\ \hline C & 41.45 & 47.0 & 46.3 & 48.65 & 42.9 & 48.81 & 49.0 & 48.4 & 46.7 \\ H & 5.51 & 5.9 & 6.4 & 5.87 & 5.9 & 6 & 5.87 & 6.01 & 6.2 \\ O\({}^{*}\) & 50.37 & 45.81 & 43.0 & 42.82 & 49.0 & 43.1 & 43.27 & 41.61 & 39.8 \\ N & 0.51 & 0.33 & n.a. & 0.16 & 0.20 & 0.46 & 0.1 & 0.17 & 0.2 \\ S & 0.054 & 0.05 & 0.1 & 0.04 & n.a. & 0.1 & 0.06 & 0.02 & 0.02 \\ Cl & n.a. & n.a. & n.a. & 0.03 & n.a. & \textless{}0.01 & 0.02 & n.a. & 0.06 \\ \hline \end{tabular} \({}^{*}\) by difference.  
\end{table} 
Table 3: Ultimate analysis of sugarcane bagasse sample compared with other studies (wt.%, dry basis). Table 5 shows a similar behavior on the analyzed parameters for the sugarcane bagasse torrefaction at 280 \({}^{\circ}\)C. At this temperature, reductions in the biomass energy yield ash-free basis reach 12%, increasing the sample's energy density by 26%. Figure 3 shows the effects of the studied torrefaction temperatures and residence times on the proximate analysis of sugarcane bagasse. Figure 3-I presents the variation of ash, fixed carbon, volatiles, and higher heating value for 30 min. Figure 3-II presents the same effects for 45 min. The results have shown that the fuel composition has the same behavior with the temperature increment for both residence times. The percentage of volatiles in the composition is reduced at higher treatment temperatures with a significant increment in the variation rate for the temperature of 280 \({}^{\circ}\)C, as previously observed in Figure 2. Fixed carbon has less than 1% of the variation for 230 \({}^{\circ}\)C, increasing more than 4% when the temperature increases by 50 \({}^{\circ}\)C.