LNG Vehicle Fueling Station Process
The process of an LNG refueling station is divided into four stages: unloading, pressure regulation, refueling, and pressure release.
1. Unloading Process
There are three methods to transfer LNG from truck tanks or containers to the LNG storage tanks at a refueling station: turbocharger unloading, low-temperature pump unloading, and combined unloading using both turbocharger and low-temperature pump.
1) Turbocharger unloading: After unloading, the tanker must be depressurized by 0.2 to 0.3 MPa, requiring the release of a large volume of gas, which takes a considerable amount of time.
2) The gas phase space of LNG tankers and storage tanks is connected, and the gas is transported to the storage tank through low-temperature pumps. Drawback: High energy consumption and complex process flow.
3) Combined unloading of turbochargers and low-temperature pumps: First, connect the vapor space of the LNG tank truck and storage tank, then disconnect them. During the unloading process, use the turbocharger to appropriately increase the pressure of the tank truck, and use the low-temperature pump to transfer LNG to the storage tank. Disadvantages of 30, 60, and 100 cubic meter LNG storage tanks: They consume electricity, produce vented gases, and have complex processes.
Prefer using the second method for unloading the train.
2. Pressure Regulation Process
The pressure inside the vehicle's gas cylinder is relatively high, typically ranging from 0.5 to 0.8 MPa. However, for transportation and storage, lower pressure is preferable. Therefore, before refueling a car, the tank needs to be pressurized, which can be done in three ways: pressure boost by a compressor, low-speed circulation by a pump, or a combination of both compressor and pump low-speed circulation.
3. Gasification Process
After being pressurized by a low-temperature pump, the gas is metered and then filled into vehicle gas cylinders by a gas filling machine, available in both single-line and double-line configurations.
When the pressure of the vehicle-mounted gas cylinder is low, use the overhead sprinkling method to reduce pressure and minimize exhaust gas emissions.
When the pressure of the vehicle-mounted gas cylinder is high, a double-line filling method is used, and the gas inside the cylinder is recycled back to the storage tank.
4. Pressure Relief Process
Excess pressure is released via a safety valve.
．LNG fueling station main equipment
LNG Storage Tanks
Internal filling design pressure
External irrigation working temperature
Ambient Temperature
External irrigation design pressure
-0.1MPa
Effective Volume
Internal灌 pressure
0.45～0.8MPa
Filling Rate
90%
External irrigation working pressure
-0.1MPa
Evaporation Rate
Internal灌design temperature
-196℃
Internal filling material
External灌design temperature
-19～50℃
External灌Material
Internal灌 temperature
-146℃
2. Low-temperature pump
Operating Temperature
-146℃
Design Head
220m
Design Temperature
-196℃
Maximum Lift
255m
Design Flow
L/min
Required Net Positive Head for Import
0.7～3.0m
2. Truck Unloading Turbocharger, Tank Turbocharger
Single-unit processing capacity
M3/h
Maximum working pressure
0.8MPa
Imported Temperature
-162℃
Design Pressure
1.6MPa
Export Temperature
-146℃
Design Temperature
-196℃
3. Gas Generator
Minimum nozzle pressure
0.41 MPa
Operating Temperature
-146℃
Traffic
0.15 cubic meters/minute
Measurement Accuracy
+0.5～-0.5%
Hose configuration
Single Tube
