## 3 Dehydrogenation Experiment  
A photograph of the constructed triple-loop dehydrogenation system is displayed in Figure 9. Detailed explanations of the reaction, heating, and chilling loops are provided in the discussion of Figure 1. The inner volumes of the dehydrogenation reactor (Part A in Figure 9) and the reservoir (Part B) were approximately 9.8 and 62.8 L, respectively. The volume of the catalyst cage within the reactor was approximately 3.0 L. Photographs of the reactor's interior and the catalyst cage are presented in Figure 10. The permeable walls of the catalyst cage were fabricated from perforated stainless steel sheet having a 22.6% open area formed with 2.5-mm-diameter holes spaced 4 mm apart. The pipe that delivered the mixture of hydrogen and LOHC vapor from the top center of the reactor to the reservoir was termed the \"flush chimney\". Figure 11 presents a schematic of the reaction loop and the actual shape of the constructed reservoir with the flush chimney (Part G) and a weir. The role of the weir was to prevent the relatively cold and hydrogen-depleted LOHC from directly flowing back into the reactor before being actively mixed with the liquid circulating through the heating loop. The weir could either be omitted or shorter.  
The tube and shell type heater (Part C) had a heat exchange area of approximately 3.2 m\({}^{2}\) and was formed by the surfaces of 64 stainless steel tubes having an outer diameter of 10 mm and a heating length of 1400 mm. When the total heating rate was 3.2 kW and the flow rate of the LOHC through the heater was 40 LPM, the log mean temperature difference between the heating surface and medium was designed to be <4.0 K. The electric power supplied to the heater was regulated to maintain an outlet medium temperature within 1 K of the specified value. The pump (Part E in Figure 9) circulated liquid DBT through the heating loop and was purchased from Hyup-Jin Chemical Pump Co. (model HJHP 32-160-12) with a displacement volume of 56.3 mL per revolution. The 2.3-kW motor drove the pump and was connected with a water-cooled coupling. All pipes through which the medium was transported between the parts comprising the dehydrogenation system were SUS316 pipes with an inner diameter of 25 mm.  
Figure 8: Flow resistance of heater at H0-DBT temperatures.  
As displayed in Table 1, the vapor pressures of H18-DBT and H0-DBT at 300 \({}^{\circ}\)C are approximately 18.9 and 9.6 kPa, respectively. The gas mixture discharged from the reservoir has considerable mole fractions of DBT vapor. The bubble column condenser (Part D), having an inner diameter of 110 mm and a height of 1000 mm, was installed to remove DBT vapor. Water was circulated between an external chiller and the cooling coil to maintain the temperature of the liquid close to 80 \({}^{\circ}\)C. The condensed DBT returned to the reservoir. The liquid levels of the reservoir and condenser were the same and were monitored through the glass window along the side of the condenser. An additional heating load was required to balance the enthalpy of evaporation and to reheat the recovered cold DBT. The dried hydrogen was then released via the flow rate measurement device, which was an MFM manufactured by LineTech (Daejeon, Republic of Korea; model: MS2400V, H2 200 SLPM).  
Figure 10: Photographs of (**a**) dehydrogenation reactor interior and (**b**) catalyst cage partially made with perforated stainless steel sheet.  
Figure 9: Photograph of constructed dehydrogenation system. A: Dehydrogenation Reactor; B: Reservoir; C: Heater; D: Condenser; E: Pump; F: Supply tank.