Unloading process and principle of Bluesky LNG filling station

Bluesky LNG Filling Station generally consists of the following main equipment: LNG storage tank, booster vaporizer, LNG Submerged pump skid, and LNG dispenser. Some customers will require adding an LNG offloading pump to speed up LNG unloading.

LNG Filling Station

This article will briefly introduce the role of each component of the Bluesky LNG filling station in unloading and filling, and explain how the LNG station realizes the unloading and filling processes.

The main station equipment involved in the unloading process is the LNG storage tank, booster vaporizer, and LNG submerged pump skid (the LNG submerged pump skid mainly plays an intermediary pipeline transmission role and does not play an auxiliary role itself). Some stations will Equipped with an offloading pump to speed up the process, the main introduction of this article is based on the LNG storage tank and booster vaporizer. Although it takes more time to unload the truck, it saves the construction cost of the LNG filling station and also saves power consumption.

LNG filling station process flow chart

The state of the storage tank when unloading:

The LNG in the LNG storage tank is almost used up, and part of the LNG in the pipelines and storage tanks has been vaporized into CNG, so the current pressure of the LNG storage tank is higher than that of the LNG truck.

Unloading process:

  • First, connect the gas phase pipeline of the LNG truck to the storage tank return pipeline of the LNG submerged pump skid. Because the pressure inside the storage tank is higher than the pressure inside the Truck, the CNG in the storage tank will enter the truck through the gas phase pipeline to balance the pressure;
  • The LNG truck then passes through the booster vaporizer to vaporize a small amount of LNG into CNG, increasing the pressure inside the truck;
  • When the pressure of the truck is higher than the LNG storage tank, LNG will flow from the truck to the LNG Submerged pump skid, and enter the LNG storage tank from the upper liquid inlet port of the storage tank through the liquid pipeline (the LNG storage tank has two upper and lower liquid inlet ports respectively) ;
  • The CNG inside the storage tank will liquefy into LNG again when it encounters low-temperature LNG liquid, which converts the CNG inside the LNG storage tank into LNG and at the same time reduces the pressure inside the storage tank, allowing the offloading to continue;
  • When the pressures between the two are balanced again, the LNG inside the LNG truck is vaporized into CNG through the booster vaporizer again, and the liquid inlet of the storage tank is switched to the lower liquid inlet to complete the unloading.

Unique equipment design provided by Bluesky in this offloading process:

LNG Skid Mounted Filling Equipment


Offloading Process: LNG truck – offloading hose – booster vaporizer & submersible pump skid – LNG storage tank


Our advantage:
  • The inside of the skid adopts a vacuum tube structure, which has a beautiful structure, good thermal insulation effect, and reduces the amount of vaporization;
  • Unique pump pool structural design, large capacity, DN65 large-diameter liquid inlet pipe ensures sufficient liquid inflow into the pump pool, high vacuum winding insulation, no frost on the pump cover, reducing cooling loss;
  • International/domestic high-quality components are selected to ensure the stability of the pump skid operation (valve: Chengdu air separation, solenoid valve: Japan SMC/Taiwan Airtac);
  • Optimized pipeline design reduces pipeline resistance.
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