# Research on Pure Hydrogen Production Using a Fuel-Processing System Combined with a PSA System
## 6 Reformer, WGS Reactor Simulation  
The simulations were performed using the Aspen Plus(r) simulator for the reformer and WGS reactor. In the simulation, the Peng-Robinson equation of state is employed to calculate the thermodynamic properties of the gas, and the steam-table method is employed to calculate the water properties, which is available in the Aspen Simulator[36]. In a reformer, the methane reforming reaction and the water-gas shift reaction are considered, and both reactions are considered to be in reaction equilibrium at given temperature and pressure conditions, assuming that the reactor is large enough to have sufficient residence time. As a raw material for hydrogen production, pure methane was introduced into the  
Figure 1: Overall process flowsheet. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline  & \multicolumn{6}{c}{**Langmuir Parameters**} \\ \hline
**Component** & \(\mathbf{a_{12}}\) **(mol/kg)** & \(\mathbf{a_{2}\times 10^{2}}\) **(mol/K/kg)** & \(\mathbf{b_{11}\times 10^{4}}\) **(1/bar)** & \(\mathbf{b_{12}}\) **(K)** & \(\mathbf{k_{i}}\)**(1/s)** & \(\mathbf{\Delta H_{i}}\)**(cal/mol)** \\ \hline \multicolumn{6}{c}{activated carbon} \\ \hline H\({}_{2}\) & 163,943 & \(-2.1\) & 0.6248 & 1229 & 0.7 & 2880 \\ CO & 33.85 & \(-9.072\) & 2.311 & 1751 & 0.15 & 4300 \\ CH\({}_{4}\) & 23.86 & \(-5.621\) & 34.78 & 1159 & 0.195 & 4290 \\ CO\({}_{2}\) & 28.7973 & \(-7\) & 100 & 1030 & 0.0355 & 5240 \\ \hline \multicolumn{6}{c}{Zeolite 5A} \\ \hline H\({}_{2}\) & 4.314 & \(-1.06\) & 25.15 & 458 & 0.7 & 2800 \\ CO & 11.8454 & \(-3.13\) & 202 & 763 & 0.063 & 5000 \\ CH\({}_{4}\) & 5.833 & \(-1.192\) & 6.0504 & 1731 & 0.147 & 5300 \\ CO\({}_{2}\) & 10.03 & \(-1.858\) & 15,781 & 207 & 0.0135 & 9330 \\ \hline \end{tabular}
\end{table} 
Table 3: Langmuir parameters for activated carbon and zeolite. fuel processor at 15 \({}^{\circ}\)C and 1 atm during simulations. The simulations were performed at temperatures from 600 \({}^{\circ}\)C to 1000 \({}^{\circ}\)C and a pressure of 1 atm to 10 atm. Simulations for the WGS reactor were conducted at 200 \({}^{\circ}\)C and at a pressure corresponding to that of the reformer. The gas flow rate of methane was controlled between 30 lpm and 61 lpm to, making 10 kW of H2. The simulation conditions for the pure processing system are summarized in Table 4. The amount of methane supplied to the process is the summation of process natural gas (PNG) and burner natural gas (BNG). At this time, PNG refers to natural gas used in reforming reactors and BNG refers to natural gas used in burners for heat duty. The PNG flow rate is controlled to make 10 kW at given temperature and pressure conditions. In the case of the water-gas shift reactor, only the water-gas shift reaction was considered when calculating the equilibrium composition under the given temperature and pressure conditions. For heat recovery, three shortcut heat exchangers were added, as shown in Figure 1. Heat exchanger B5 is a heat exchanger for cooling the reformed gas temperature to the operating temperature of the WGS reactor, and B2 is a heat exchanger for making the outlet reformed gas temperature the same as the PSA inlet temperature. Any remaining water at the outlet of the water-gas shift reactor must be removed for the PSA process. Heat exchanger B2 and water separator B1 are added to the simulation for water removal by condensation. In the PSA process, over 99.97% hydrogen is produced, where the operating conditions for the hydrogen-purification system are 15 \({}^{\circ}\)C and 9 atm. Figure 2 shows the simulation results of each gas composition in the WGS reactor outlet flow according to the reformer temperature. As is shown in the figure, the concentration of H2 increases as the reformer temperature increases. Since the operating pressure of PSA is 9 atm for hydrogen purification, a compressor is needed to increase the pressure of the stream entering the PSA to 9 atm. The efficiency of the compressor was calculated as a mechanical efficiency of 0.8 and an isentropic efficiency of 0.8 [45].