# Valorization of Insulation Cellulose Waste as Solid Biomass Fuel
## 3 Results and Discussion
### Chemical Properties and Combustion Characterization  
Table 3 shows the LHV of the different combinations' proximate and ultimate analyses, as well as their ashes composition. The CFP showed an LHV value adequate for its use as biomass fuel [12]. As expected, the lower heating power of the pellets decreased when additives were used [18]. This partial substitution of CFP by less energetic products reduced LHV by 5.3% and 15.1% for the sugar at 1% and 2% of dosage, respectively. Lignosulfonate at the same dosages reduced CFP LHV by 4.6% and 9.3%, respectively, demonstrating its higher energetic power than sugar. Ultimate analysis showed a slight increase in the nitrogen that could potentially increase the pollutant NOx's combustion emissions of combinations containing binders, particularly for the combination CFP + 2% LS. Despite the CFP + 2% LS combination \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Analysis** & **CFP** & **CFP + 1\% S** & **CFP + 2\% S** & **CFP + 1\% LS** & **CFP + 2\% LS** \\ \hline
**Lower heating** & & & & & \\
**value (MJ/kg)** & & & & & \\ \hline
**Ultimate analysis (wt\%)** & & & & & \\
**N** & 0 & 0.11 & 0.17 & 0.13 & 0.88 \\
**C** & 39.15 & 38.67 & 34.68 & 38.39 & 33.39 \\
**H** & 5.48 & 5.33 & 5.14 & 5.45 & 5.05 \\
**S** & 0 & 0 & 0 & 0 & 0 \\
**O** & 55.38 & 55.89 & 60.01 & 56.04 & 60.69 \\ \hline
**Proximate analysis (wt\%)** & & & & & \\
**Moisture** & 7.83 & 8.65 & 6.05 & 6.5 & 6.64 \\
**Volatiles** & 54.49 & 51.17 & 46.59 & 51.59 & 45.81 \\
**Fixed carbon** & 26.97 & 28.42 & 27.61 & 27.6 & 28.71 \\
**Ash** & 10.71 & 11.76 & 19.75 & 14.31 & 18.84 \\ \hline
**Ashes chemical composition (wt\%)** & & & & & \\
**C** & 16.78 & 16.25 & 30.25 & 13.45 & 23.65 \\
**O** & 57.93 & 56.73 & 49.05 & 59.19 & 52.21 \\
**Si** & 5.04 & 7.15 & 5.02 & 7.93 & 4.29 \\
**B** & 16.42 & 13.09 & 10.03 & 14.4 & 15.67 \\
**Ca** & 3.83 & 6.78 & 5.65 & 5.03 & 4.18 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Combustion characterization of the CF combinations and the ashes’ chemical compositions. Figure 6: Water absorption. presenting 0.88% of N, all the combinations meet the parameters of the 17225-6 Standard. Unexpectedly, lignosulfonate combinations did not show the presence of sulfur, probably because of its low content in lignocellulosic and the low dosages considered. All the pellet combinations showed similar combustion characteristics, highlighting their potential as a green energy source compared to other non-conventional biomass fuels [18; 42; 43; 44; 45; 46]. All the combinations showed adequate combustion characteristics, except those with high ash content due to the presence of Boron salts in their composition. These oscillated in the range of 10.71-18.84, much higher than the 10% required by the ISO 17225-6 Standard for non-woody type B pellets. The use of additives decreased the CFP volatile matter content and increased the fixed carbon that could facilitate a more stable combustion. Figure 7 shows the thermogravimetric analysis of the raw CFP and additives containing pellets. Thermogravimetric curves (TG) show the typical four stages throughout the combustion processes: dewatering, volatilization and burning, char burning and burnout. As the DTG curve depicts, the combustion of CFP generates two exothermic peaks due to the burning of volatile and fixed carbon, the fixed carbon peak being higher than the one due to volatile burning. DTG curves corresponding to the combinations with additives show a decrease in the volatile peaks that suggests a higher proportion of fixed carbon in these combinations, in accordance with the proximate analysis test results. This reduction in the volatiles could be related to a more stable combustion that could provide other beneficial consequences by using sugar or lignocellulosic for pellet manufacturing. DTA curves showed a decrease in the mass loss rate in the volatile stage for the binder-containing combination compared to the raw CFP one, which also could be considered an indicator of a more stable combustion.