# Glycerol Steam Reforming in a Pilot Plant: Effect of Temperature and Catalyst Load
## 2 Materials and Methods  
### Glycerol Pretreatment  
Glycerol was obtained from a biodiesel plant (Green Fuel Extremadura), which produces approximately 1.1 \(\times\) 10\({}^{8}\) kg per year, with the subsequent generation of glycerol (around 1.1 \(\times\) 10\({}^{7}\) kg per year). Obviously, this glycerol is not pure and therefore some properties are different compared to pure glycerol, as it presents some impurities that might modify its behavior in different uses. Therefore, a characterization of crude glycerol was carried out, including proximate, ultimate analysis and high heating value determination. The main results are included in Table 3. As can be inferred, it was proven that glycerol presented some impurities that could interfere with a suitable performance of this product during steam reforming. For instance, S content could imply hydrogen sulfide generation during steam reforming, which could be a considerable problem for catalyst deactivation through poisoning. Consequently, to purify glycerol to remove impurities, it was heated at 120-130 \({}^{\circ}\)C for 120 h, to reduce moisture and provoke precipitation of salts, which are filtered and removed. Thus, the impurities of glycerol were considerably reduced, allowing its use in further treatments during steam reforming.  
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Description** & **Details** & **Reference** \\ \hline Glycerol steam reforming in an integrated & A simulation of an integrated process plant was carried out in & \\ waste cooking oil biodiesel production & order to improve the efficiency of the system by maximizing & \\  & hydrogen production in GSR, with a total yield of 13\% and a & \\  & total yield for biodiesel production of 92.5\% & \\ \hline Integrated hydrogen production from & In a biorefinery or circular economy context, a simulation of an & \\  & integrated biodiesel and hydrogen production was carried out, & \\  & obtaining high-quality biodiesel and the following GSR & \\  & conditions for a high H\({}_{2}\) production: W/G = 4.5, T = 750 \({}^{\circ}\)C. & \\ \hline Use of Ni/CeO\({}_{2}\) catalysts for & CeO\({}_{2}\) nanosphere-supported Ni catalysts were prepared & \\  & through wet impregnation, for GSR. Direct H\({}_{2}\) reduction & \\  & without calcination was preferred, as high glycerol conversion & \\  & (95\%) and catalytic stability (35 h) were achieved. & \\ \hline LaAlO\({}_{3}\) as a catalyst for glycerol steam & Different catalysts were studied, adding Ni, Ni-Ce or Ni-La, & \\  & reforming, among other processes & among others, observing that the latter showed a high & [41] \\  & coke resistance. & \\ \hline Catalytic steam reforming of glycerol over & High glycerol conversions (exceeding 83\%) were achieved, with & \\  & stable hydrogen production & a high H\({}_{2}\) yield (85\%) and a long catalyst stability (1000 min). & [42] \\ \hline Effect of noble metals on Ce\({}_{2}\)O\({}_{3}\)-Al\({}_{2}\)O\({}_{3}\) & Different metals like Ir, Pt and Pd were studied, proving that & \\  & catalysts for hydrogen production via & Pt/CeAl catalyst was more selective toward H\({}_{2}\) production, & \\  & glycerol steam reforming & whereas Ir/CeAl tended toward sintering due to the weak & \\  & metal–support interaction & \\ \hline \hline \end{tabular}
\end{table}
Table 2: Recent works related to glycerol steam reforming.