## 3 Results and Discussions  
### Simulation Verification of BTS Using Experimental Test Data  
The results obtained using the pressure loss model of the BTS were compared with experimental test data. The test method was as follows, and the test environment is presented in Tables 3 and 4.  
* After filling the P-tank with the bulk, the air pressure was increased up to 3.8 bar.
* After checking the set pressure, the bulk transfer valve from the P-tank to the surge tank was opened.
* The pressure rise in the surge tank was checked through the monitoring panel of the bulk transfer control box.  
The following test results were obtained at the Korea Marine Equipment Research Institute in South Korea. Figure 8 shows a land-based testbed for the BTS (left) and the piping and instrumentation diagram of the real testbed (right).  
Figure 9 and Table 5 present the results of a comparison between simulation and test data. The simulation was performed under the same conditions as the test. The simulation of the pressure loss in Figure 9 was carried out using MATLAB/Simulink. Here, it was performed without the air booster. The input pressure supplied by the compressor started at 3.8 bar and rapidly decreased in the vertical pipe section. Then, in the horizontal and bending pipe sections, the decrease was relatively less (loss of 1.14 bar). Accordingly, an output pressure of 2.66 bar was obtained. The error rate of the pressure was confirmed to be 4.27%. The reason for the error is that in the case of bulk transfer in the  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Dry Bulb Temperature (\({}^{\circ}\)C)** & \multicolumn{3}{c}{**Relative Humidity (\%R.H.)**} \\ \hline \(10\pm 1\) & \multicolumn{3}{c}{\(20\pm 5\)} \\ \hline \hline \end{tabular}
\end{table}
Table 3: Test environment for simulation.  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Condition** & \begin{tabular}{c} **Before** \\ **Transfering** \\ \end{tabular} & \begin{tabular}{c} **During** \\ **Transfering** \\ \end{tabular} & \
\begin{tabular}{c} **During** \\ **Transfering** \\ \end{tabular} &
\begin{tabular}{c} **After** \\ **Transfering** \\ \end{tabular} \\ \hline
**P-tank pressure** & 3.8 & 3.7 & 3.6 & 3.6 \\
**Surge tank pressure** & 0.2 & 0.5 & 1.5 & 1.8 \\ \hline \hline \end{tabular}
\end{table}
Table 4: Comparison of empirical data and simulation results.  
Figure 7: Storage tank dynamics with on/off valve signal: (**a**) inlet valve on/off signal of storage tank; (**b**) storage tank level simulation according to changing valve signals; (**c**) outlet valve on/off signal of storage tank.  
In this study, case simulation was performed to observe the change in the pressure loss according to the specifications of the pipeline when designing the BTS. The simulation was performed by fixing the inlet pressure and the length of the entire pipe to 3.8 bar and 161.57 m, respectively. Table 6 lists some parameters of the pressure loss simulation of the BTS.  
The case simulation of the pressure loss model was performed by entering the inlet pressure as 3.8 bar and specifying different variables for each case. Proper air pressure, piping layout design technology, and prescribed design guidelines are required to transport the bulk without clogging at the desired transport rate. In addition, the operating pressure and the amount of air determine the system cost. Therefore, an optimal design technology is required for the system.  
Figure 10 shows the pressure loss according to the unit length of the vertical and horizontal pipes. When the length of the vertical pipe exceeds 103 m in the BTS design, the outlet pressure of 0 bar is no longer allowed to transfer the bulk under a theoretical background.