The process of LNG filling station mainly includes three parts: unloading process, storage tank pressure regulation process, and gas filling process.

1. Unloading process

The LNG unloading process is the operation of transferring the LNG in the container or tanker to the LNG storage tank. The LNG unloading process mainly includes the submersible pump unloading method.

This method is to transfer the LNG from the tanker to the LNG storage tank through the submersible pump in the system. The process flow of the LNG unloading is shown in Figure 1. The submersible pump unloading method is that the LNG liquid enters the submersible pump through the unloading port of the LNG tanker, and the submersible pump pressurizes the LNG and then fills it into the LNG storage tank. The gas port of the LNG tanker is connected with the gas phase pipe of the storage tank, and the BOG gas in the LNG storage tank is charged into the LNG tanker through the gas phase pipe. The gas-phase pressure of the tank increases due to the increase of liquid. The whole unloading process does not need to release the pressure of the storage tank, and the unloading operation can be carried out directly.

2. Tank pressure regulation process

The storage tank pressure regulation process is an operation that needs to adjust the saturated vapor pressure of LNG in the storage tank before adding gas to the LNG vehicle. This operation process includes a submersible pump pressure regulation process.

The LNG liquid enters the submersible pump through the liquid outlet of the LNG storage tank. After being pressurized by the submersible liquid pump, it enters the pressurized gasifier for gasification. The gasified natural gas is returned to the gas phase of the LNG storage tank through the gas phase pipe of the LNG storage tank. space for pressure regulation of LNG storage tanks. Therefore, the use of submersible pumps has fast pressure regulation speed, short pressure regulation time and high pressure.

3. Gas filling process

In the gas filling process, the submersible pump has become the first choice for the gas filling process of the LNG filling station due to the fast filling speed, high pressure and short filling time of the submersible pump.