## 3 Results
### Feedstock Properties
\begin{table}
\begin{tabular}{l l} \hline \hline
**Ash Composition** & **(\%m/m, ppm).** \\ \hline Na\({}_{2}\)O & 0.4 \\ MgO & 6.28 \\ Al\({}_{2}\)O\({}_{3}\) & 0.52 \\ SiO\({}_{2}\) & 3.47 \\ P\({}_{2}\)O\({}_{5}\) & 4.33 \\ ClO & 307 ppm \\ CaO & 8.78 \\ ZrO\({}_{2}\) & 5.79 ppm \\ SO\({}_{3}\) & 3.57 \\ K\({}_{2}\)O & 72.02 \\ Fe\({}_{2}\)O\({}_{3}\) & 0.309 \\ ZnO & 875 ppm \\ CuO & 228 ppm \\ MnO & 340 ppm \\ Rb\({}_{2}\)O & 776 ppm \\ SrO & 598 ppm \\ \hline \hline \end{tabular}
\end{table} 
Table 2: CPH ash composition. The composition of cocoa shell ash shows distinctive characteristics that directly influence its behavior during combustion and waste management. The content of alkali and alkaline earth oxides is a prominent aspect, in particular because of the high percentage of K\({}_{2}\)O, which reaches 72.02%. This value, which is significantly higher than the range identified by [PERSON] et al. (2015) in common biomasses (2.9-63.9%) and much higher than in conventional coals (0.29-4.15%), has important implications [34]. The high presence of K\({}_{2}\)O acts as a flux, reducing the ash melting temperature and facilitating slag formation as the temperature increases. This phenomenon causes inorganic elements in the biomass, such as K\({}_{2}\)O, to be incorporated into the slag, generating problems such as abrasion in the combustion systems [35]. On the other hand, the considerable content of CaO (8.78%) and MgO (6.28%) plays a relevant role in the behavior of the ashes. Both oxides increase the viscosity of the slag, which can favor the formation of deposits on the heat exchange surfaces during combustion. Comparing these values with those of widely used biomasses, such as palm kernels (CaO 9.2%, MgO 6.5%) and pine chips (CaO 7.89%, MgO 2.43%), it is observed that cocoa shells have a similar potential for applications in energy systems [36]. This suggests that, although there is a risk of deposits and abrasion, the expected behavior of ash is comparable to that of other successful biomasses in industrial applications. As for the SiO\({}_{2}\) content, the value recorded is 3.47%, considerably lower than that of other biomasses such as sugarcane, which can contain up to 80.2% SiO\({}_{2}\). Although SiO\({}_{2}\) may contribute to the formation of abrasive and viscous layers in ash, its low percentage in cocoa husk suggests a lower impact on abrasion and accumulation in equipment [37]. Studies such as [PERSON] et al., which investigated the ash melting behavior in blends of reeds and woody fuels, recommend blending biomasses with high SiO\({}_{2}\) contents with others of lower content to improve these properties [38]. This approach might be unnecessary for cocoa husk, given their favorable chemical profile. The analyses of cocoa shell biomass ash largely align with the parameters of the samples reported from the ENCE thermal plant except for the K\({}_{2}\)O content, which is significantly higher in cocoa shells (72.02%) [39]. This high K\({}_{2}\)O content has important implications, since potassium acts as a flux, facilitating the formation of deposits in boilers and increasing the risk of abrasion and corrosion in combustion equipment. These characteristics could require stronger materials and more frequent maintenance in industrial systems if cocoa shells are used as an energy source. However, this high potassium content can also be an advantage in agricultural applications, as the ash could be used as a fertilizer rich in potassium, an essential nutrient for crop development. This circular economy approach highlights the dual potential of cocoa husk biomass in both the energy and agricultural sectors, depending on the management and valorization strategies adopted.