# Influences of the Pretreatments of Residual Biomass on
## 2 Materials and Methods
### Processing of Devolatilization Data  
For each pair \"biomass kind-temperature\", three repetitions of devolatilization were performed (i.e., three pellets of the same kind were devolatilized at each temperature). Each pellet was devolatilized individually and completely before feeding the following one. Because of this procedure, as already evidenced in [10; 23], the experimental process is intrinsically at unsteady-state. Thanks to the hypothesis of N\({}_{2}\) as the internal standard, it was possible to determine the instantaneous molar flow rates of the gases (\(F_{i,out}\), with \(i\) as the generic gaseous species produced by the devolatilization tests, quantified by the ABB system: H\({}_{2}\), CO, CO\({}_{2}\), CH\({}_{4}\), C\({}_{3}\)H\({}_{8,\text{eq}}\).). Figure 1 (Section 3.1) shows examples of these instantaneous flow rates from individual devolatilizations as functions of time (\(t\)), characteristically shaped as asymmetric peaks [29; 30]. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Material** & **Sand** \\ \hline \(d_{p}\) (\(\mu\)m) & & 212–250 \\ \(\rho_{p}\) (kg m\({}^{-3}\)) & & \(2.6\times 10^{3}\) \\ \hline \(T\) (\({}^{\circ}\)C) & \(u_{m\!f}\) (cm s\({}^{-1}\)) & **Generalized Geldart Group**[27] \\ \hline \(700\) & 2.4 & B \\ \(800\) & 4.4 & B \\ \(900\) & 2.9 & B \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Physical and fluid-dynamic properties of sand, adapted from [10]: particles diameter (\(d_{p}\)) and particle density (\(\rho_{p}\)); minimum fluidization velocity (\(u_{m\!f}\)) in N\({}_{2}\) as a function of temperature (T), with the indication of the related generalized Geldart Group [26]. This work introduces a further method to analyze devolatilization performances, which focuses on the quantitatively most representative moment of unsteady-state devolatilizations of individual pellets, i.e., the top of \(F_{i,out}\) devolatilization peaks as functions of time (see Figure 1), when the highest gas release occurred. The procedure to elaborate this data follows:  
1. for each set \"biomass kind-temperature\" and for each of the three repetitions, the highest released flow rate (i.e., peak top of \(F_{i,out}\) in Figure 1) was identified for each quantified species (\(i=\mathrm{H_{2}}\), CO, CO\({}_{2}\), CH\({}_{4}\), and C\({}_{3}\)H\({}_{8,\mathrm{eq}}\));
2. a neighborhood of 7 \(F_{i,out}\) experimental points was selected, centered on the considered peak top;
3. the arithmetic average (\(F_{i,out}^{p}\), Equation (4), where \"p\" superscript means \"peak\") was calculated out of these 7 points. In addition, the distribution among peaks of released gases--namely H\({}_{2}\), CO, CO\({}_{2}\), CH\({}_{4}\), and C\({}_{3}\)H\({}_{8,\mathrm{eq}}\)--was calculated, in terms of molar fractions on a nitrogen-free basis  
Figure 2: Experimental results of devolatilization tests for all kind of pellets, as functions of temperature (700, 800, and 900\({}^{\circ}\)C): (**a**) integral average gas yield (\(\eta^{av}\), Equation (1)); (**b**) integral average H\({}_{2}\)/CO molar ratio (\(\lambda^{av}\), Equation (2)); (**c**) integral average carbon conversion (\(\chi_{c}\), Equation (3)); WSP data adapted from [10]. (\(Y_{i,out}^{p}\), Equation (5)). For each temperature value and each gaseous species, three points were obtained (one per test), corresponding to the three repetitions for each kind of biomass; therefore, for the generic gaseous species \(i\), 9 values of \(Y_{i,out}^{p}\) were obtained, evenly distributed on the three temperature levels 700, 800, 900 \({}^{\circ}\)C.  
\[ \begin{gathered} F_{i,out}^{p}=\frac{\sum_{k=1}^{p}F_{i,out,k}}{ 7}\\ with\ i=H_{2},CO,CO_{2},CH_{4}\ and\ C_{3}H_{8,eq}\ ;\ k=number\ of\ experimental\ point\\ \end{gathered}  \tag{4}\]  
\[Y_{i,out}^{p}=\frac{F_{i,out}^{p}}{\sum_{i}F_{i,out}^{p}}with\ i=H_{2},CO,CO_{ 2},CH_{4}\ and\ C_{3}H_{8,eq} \tag{5}\]  
Moreover, a parameter called \"specific maximum gas production\" (_SMGP_) was introduced and calculated by Equation (6).