## 5 Experimental Measurement  
In the experimental measurement, by setting the pressure to 76.3 bar and cooling the equipment to temperatures between 4.7 and 4.9 \({}^{\circ}\)C, the conditions were set in the region of hydrate structure formation, but before the freezing point of water. After switching on the pump and adjusting the flow rate using a frequency converter, the ultrasonic flow meter indicated a flow rate of 0.06 L\(\cdot\)s\({}^{-1}\). A gas volume of 1.3 m\({}^{3}\) was forced into the device. The mathematical model (Figure 4) predicted the highest methane uptake from the beginning of the experiment to 610 s during the circulation of water through the high-pressure pump. During the experiment, the high-pressure pump was disconnected from operation as early as 480 s due to a visual change in the environment at the bottom of the VN2 vessel. The resulting mass of crystallized water and hydrate was trapped on the strainer at the bottom and clogged the circulation circuit. The ultrasonic flowmeter indicated a loss of signal (i.e., it did not signal any flow). The pump was subsequently disconnected from service to protect it. From a time, point of 610 s, a stabilization phase occurred. According to the simulation, only 121.9 g of unbound natural gas was present in the system. The stabilization phase lasted for 25 min after which the pressure started to rise slightly, indicating that a gas re-release process was occurring. According to the simulation, just by maintaining the temperature and pressure conditions in the non-pump phase, the presence of methane gas was reduced to a mass of 98.6 g. From an energy point of view, maintaining the stabilization phase is energetically disadvantageous since the amount of saturated natural gas is negligible compared to the energy expended on cooling. The time evolution of the different components involved in the hydrate formation can be seen in Figure 4.  
Figure 3: Cooling system. As the water was supplied in excess, there was a pressure drop due to the saturation of the water with gas. The pressure conditions recorded during the measurement are shown in Figure 5.  
In order to achieve a high rate of hydrate formation, it is necessary to stabilize the temperature conditions with as little deviation from the desired value as possible during the measurement. The hydrate formation is characterized by an increase in temperature,  
Figure 4: Prediction of hydrate formation by mathematical model. Figure 5: Pressure curves. which was manifested by the heating of the vessel VN1 in Figure 6. The heat released by the hydrate formation is efficiently dissipated into the aqueous phase and dissipated on the vessel walls, which are continuously cooled. Due to the saturation of the water with gas, there is a sharp drop in pressure. When the hydrate formation was considered complete based on visual assessment of the hydrate quality through the sapphire visor, the process of pressure reduction occurred. The depressurization is initiated by opening the drain valve at the bottom of vessel VN2. The pressure reduction is accompanied by the discharge of water from the system. After the water has been drained, the system is flushed with cooled natural gas until complete drying and compaction of the formed hydrate is achieved. The volume of water in the primary circuit system, after determining the volumetric capacities of the individual components, is 22.1 L. After draining and volume measurement, the water volume was 15.6 L. The simulation at the end of the experiment determined the number of moles of crystallized water to be 262 moles. This represents 4.7 L and 6.5 L of crystallized hydrate remained in the experimental apparatus. The deviation of the simulation from the measurement may be due to less accurate water capture in the measuring tank, as the entire process was complicated by high pressure and volume losses during collection.