## 2 Preliminary Experiments
### Gas Infiltration through Catalyst Bed  
The gas infiltration experiments were conducted to understand the influence of the rotation speed and the amount of catalyst pellets on the gas isolation ability of the rotating packed bed-type reactor. The experimental results assisted in determining the lower limit of the rotation speed. The LOHC material was mimicked with water, the hydrogen with air, and the catalyst with dummy alumina pellets. The target amount of air infiltration was 33.3 LPM (Liter per minute), which corresponds to an average hydrogen production rate of 2.0 m\({}^{3}\)H\({}_{2}\)/h. If 50% dehydrogenation of 25 L of H18-DBT occurred during 500 min, the average hydrogen production rate was approximately 1.0 m\({}^{3}\)H\({}_{2}\)/h. The gas infiltration experiments were performed within a viewable cylindrical enclosure containing the rotating packed bed. Figure 2 displays a photograph of the test cell equipped with a rotatable synchronous camera, a schematic of the test apparatus, and a photograph of the packed bed partitions. The enclosure had an inner diameter of 380 mm and a height of 67 mm, which was milled from a stainless steel (SUS) square block with a side length of 400 mm. The top end of the SUS block was welded to a 3-mm-thick flange, which was screw-connected to a 20-mm-thick acrylic plate for visibility. The bottom end of the block was welded to a 10-mm-thick stainless plate. One of the sidewalls of the enclosure had an air inlet port through which a specified amount of air was supplied by an air compressor via a flow meter. A pressure tap was installed on another sidewall to measure the pressure difference between the open center and the outer ring of the test enclosure. The rotor was driven by an electric motor, gearbox, and tachometer assembly. The hollow vertical shaft of the rotor had slots near the bottom plate to serve as a water-filling port and was extended above the reactor assembly to support and drive an image-recording camera. The compact cylindrical cage had an outer diameter of 360 mm and a height of 55 mm and was filled with dummy alumina pellets. The top plate of the cage was 5-mm-thick acrylic plate and the bottom plate was 2-mm-thick SUS plate. The gap between the rotor's top plate and the top wall of the enclosure was 10 mm, and the rotor's bottom plate was in close contact with the bottom wall of the enclosure. The eight radial vertical walls of the cage were 2-mm-thick SUS plate. The five concentric vertical walls of the cage were permeable wire mesh, which were placed at radii of 100, 120, 140, 160, and 180 mm. When \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Experiment** & \multicolumn{3}{c}{**H18-DBT**} & \multicolumn{3}{c}{**H0-DBT**} \\ \cline{2-7}
**Temperature** & **Density** & **Viscosity** & **Vapor Pressure** & **Density** & **Viscosity** & **Vapor Pressure** \\ (\({}^{\circ}\)**C**) & **(kg/m\({}^{3}\))** & **(mPa-s)** & **(Pa)** & **(kg/m\({}^{3}\))** & **(mPa-s)** & **(Pa)** \\ \hline
20 & 913.4 & 252.3 & 4.22 \(\times\) 10\({}^{-41}\) & 1044 & 44.18 & 9.91 \(\times\) 10\({}^{-5}\) \\
70 & 881.5 & 15.96 & 9.91 \(\times\) 10\({}^{-17}\) & 1008 & 6.457 & 5.08 \(\times\) 10\({}^{-2}\) \\
97 & 864.2 & 6.426 & 6.61 \(\times\) 10\({}^{-10}\) & 989.1 & 3.272 & 4.95 \(\times\) 10\({}^{-1}\) \\
112 & 854.7 & 4.403 & 3.99 \(\times\) 10\({}^{-7}\) & 978.3 & 2.428 & 1.61 \(\times\) 10\({}^{0}\) \\
300 & 734.6 & 2.399 & 1.89 \(\times\) 10\({}^{4}\) & 843.9 & 0.7911 & 9.56 \(\times\) 10\({}^{3}\) \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Properties of perhydro-DBT and DBT according to experimental temperatures [9; 23]. the cage was partially filled, the radial sections (1, 2, and 3) displayed in Figure 3a were left empty with a porous bed volume of approximately 2210 cc. When the cage was fully filled, only radial section 1 was left empty, as depicted in Figure 3b, with a bed volume of approximately 3870 cc. Figure 3: Photographs of (**a**) partially filled and (**b**) fully filled pellet cage.