## 3 Results
### Air Gasification Analysis of CPHs  
Air gasification experiments were conducted by varying the temperature in the range of 500 \({}^{\circ}\)C to 700 \({}^{\circ}\)C. This study focused on the influence of temperature while keeping the flow rate of the gasification agent (air) constant at 100 cm\({}^{3}\)/min. The residence time was maintained constant throughout the experiments to ensure reliable comparisons across different temperatures. Table 7 shows the effect of temperature on the yield of charcoal obtained during air gasification, as well as its proximate analysis and PCS in both dry and wet bases. A reduction in charcoal yield is observed as the temperature increases. The proximate analysis shows a decrease in volatile matter, a slight increase in ash content, and minimal effect on fixed carbon content, resulting in a limited impact on both dry and wet PCS values. The solid residue yields obtained in this study are higher than those in a previous study on almond husks by [PERSON] et al. (2006), although the PCS values were similar, ranging from 21.1 to 21.7 MJ/kg for temperatures between 650 and 800 \({}^{\circ}\)C [53]. Gasification experiments were performed in triplicate at each temperature to validate the reproducibility of the data. The low standard deviations across all temperature conditions (\(\leq\)0.06% for H\({}_{2}\), \(\leq\)0.04% for CO) indicate high repeatability. The observed trends remained consistent across replicates, with H\({}_{2}\) content increasing significantly from 0.23% at 500 \({}^{\circ}\)C to 9.98% at 700 \({}^{\circ}\)C, with a standard deviation of \(\pm\)0.06%. The average results, shown in Table 7, include gas yields, solid residues, and syngas composition. These results align with previous studies on biomass gasification, reinforcing the reliability of the approach. The feasibility of the process is further supported by the potential use of cocoa shell biomass as a low-cost, sustainable feedstock for syngas production. Figure 6 shows the evolution of H\({}_{2}\), CO, CH\({}_{4}\), and CO\({}_{2}\) over time, with an increase observed as the temperature rises. This gas in the air gasification process has a pyrolytic origin, which is why its accumulated moles over time follow a linear trend like the one observed in the pyrolysis experiments (compared with Figure 5). Regarding CO, from 600 \({}^{\circ}\)C onwards, a trend is observed where the gasification process stabilizes around the reaction C + \(\
icefrac{{1}}{{2}}\) O\({}_{2}\)\(\rightarrow\) CO, leading to a nearly constant CO at 700 \({}^{\circ}\)C throughout the experiment. A slight contribution from the Boudouard reaction (C + CO\({}_{2}\) = 2 CO) may also be occurring, as indicated by the decrease in [CO\({}_{2}\)] over time at 700 \({}^{\circ}\)C. CH\({}_{4}\) also originates from pyrolysis, but a sharp reduction is observed compared to its concentration in pyrolysis experiments. This decrease suggests that CH\({}_{4}\) may be involved in other reactions, such as CH\({}_{4}\) + \(\
icefrac{{1}}{{2}}\) O\({}_{2}\)\(\rightarrow\) CO + 2 H\({}_{2}\) or CH\({}_{4}\) + O\({}_{2}\)\(\rightarrow\) CO\({}_{2}\) + 2 H\({}_{2}\). A clear decrease in CO\({}_{2}\) concentration is seen compared to the pyrolysis experiments (Figure 5). This suggests that the reaction C + O\({}_{2}\)\(\rightarrow\) CO\({}_{2}\) does not significantly contribute to the overall gas composition during the air gasification of CPHs.