Know more about LNG loading arm
The Liquefied Natural Gas (LNG) loading arm is a specialized device designed for the loading and unloading of cryogenic liquefied natural gas (LNG, stored at -162°C under atmospheric pressure). It mainly connects LNG storage tanks (or tank trucks, ships) to transport vehicles, enabling the closed transfer of cryogenic liquefied natural gas. Due to LNG's characteristics of ultra-low temperature, easy vaporization, flammability, and explosiveness, the LNG loading arm differs significantly from ordinary liquid loading arms (e.g., gasoline or diesel loading arms) in terms of material, structure, and safety design. It is a core equipment in the LNG supply chain that ensures the safety and efficiency of loading and unloading operations.
1. Column
To rationalize the force on the pipeline, it is used to support the weight of the arm, distribute the load of the swivel joint, and ensure stable installation. When assembling the column with the trestle, bolt connection or welding can be adopted.
2. Inner Arm Lock
Used to lock the arm in place when the arm is in the stowed position. This prevents damage to the arm or surrounding structures caused by strong winds or operations by unauthorized personnel.
3. Interface
It is the connection part between the arm and the pipeline or tank truck, usually using flange connection.
4. Swivel Joint
Used for the rotational movement of the arm to meet the normal operating range (envelope range). Conventional cryogenic loading arms adopt swivel joints to realize three-dimensional movement and the docking of flange interfaces.
5. Inner Arm
The part between the interface and the outer arm, which can rotate on the horizontal plane.
6. Outer Arm
As the main part of the cryogenic loading arm, it can rotate 360° in the horizontal direction and 75° in the vertical direction.
7. Balancing System
Used to balance the weight of the outer arm, making the arm flexible and easy to operate. The balancing system is a spring cylinder, and the spring inside the cylinder is a compression spring.
8. Cryogenic Breakaway Valve
When the pipeline is subjected to excessive force, the breakaway valve installed on the pipeline breaks from the middle, and the built-in valves at both ends close automatically, thereby preventing liquid leakage and protecting the pipeline from being pulled apart. For example, if a tank truck driver accidentally drives away before the pipeline is disconnected during loading/unloading, or a ship drifts accidentally, without the breakaway valve, the equipment would be pulled away and damaged.
Performance Characteristics
a. It enables the loading and unloading equipment to break automatically and quickly in emergency situations, while no breakage occurs during normal operations.
b. The two separated parts after breakage can be effectively sealed, ensuring no leakage of gas (liquid).
c. Anti-static design and fire resistance test ensure that the valve can be operated normally in special situations.
The LNG loading arm is a specialized loading and unloading equipment adapted to the ultra-low temperature, easy vaporization, flammable, and explosive characteristics of LNG. Its core design centers on three goals: "cryogenic toughness, cold insulation and leakage prevention, and safe controllability". Through special materials, thermal insulation structures, and multiple safety devices, it ensures the efficient transfer and safety protection of LNG during loading and unloading processes.
