Extreme Challenges in LNG Loading and Unloading -
Technological Innovations and Industrial Applications of Low-Temperature Loading Arms
As an important part of clean energy, the storage and transportation of liquefied natural gas (LNG) relies on an ultra-low temperature environment of -163℃. In the LNG loading and unloading link, the low-temperature Loading Arm is the key equipment connecting the transport ship, tank truck and receiving station. It needs to cope with multiple extreme challenges such as ultra-low temperature embrittlement, heat conduction control, and seal failure at the same time. Its technical level directly affects the development quality of the LNG industry.
The breakthrough of low-temperature materials is the foundation for LNG loading arms to realize ultra-low temperature operations. Since ordinary metal materials will undergo severe embrittlement in the ultra-low temperature environment of -163℃, the main materials of LNG loading arms generally use austenitic stainless steel or aluminum alloy. These materials have excellent low-temperature toughness and can maintain structural stability in the temperature range of -196℃ to +50℃. Large-diameter LNG marine loading arms mostly use aluminum alloy to build the arm body, which not only effectively reduces the weight of the equipment and improves operational flexibility, but also further enhances the low-temperature embrittlement resistance of the material through a special heat treatment process.
The thermal insulation structure design is the core technology to control heat conduction and prevent LNG gasification. The LNG loading arm adopts a double-layer vacuum insulation structure. The inner pipe is used to transport LNG, and a vacuum interlayer is formed between the outer pipe and the inner pipe to minimize heat conduction. At the same time, multi-layer thermal insulation wrapping technology is adopted at key parts such as pipe interfaces and rotary joints to further improve the thermal insulation effect. Through these designs, the gasification rate of LNG during loading and unloading can be controlled at an extremely low level, ensuring transportation efficiency and avoiding safety risks caused by increased gasification pressure.
The comprehensive upgrade of the safety system is an important guarantee for LNG loading arms. Such equipment is equipped with a special low-temperature emergency breakaway valve, and its seals are made of special materials resistant to ultra-low temperatures, which can achieve reliable sealing in an environment of -163℃. At the same time, the equipment is integrated with a vacuum℃monitoring sensor to real-time monitor the vacuum state of the thermal insulation interlayer. Once the vacuum℃drops, an alarm is immediately triggered to prevent the aggravation of heat conduction leading to a large amount of LNG gasification. In the application practice of overseas LNG receiving station projects, domestic low-temperature loading arms have successfully realized the unloading of LNG at -163℃, and the leakage rate of core components is an order of magnitude better than international standards, showing the technical strength of domestic low-temperature loading arms.
Intelligent upgrading is the development trend of LNG loading arms. With the advancement of smart port construction, LNG loading arms are gradually integrating technologies such as visual recognition, automatic docking, and remote control. Intelligent marine LNG loading arms have been successfully applied in domestic ports, realizing unmanned operation of the loading and unloading process. Operators can remotely issue "one-click docking" instructions through the smart platform, and the equipment automatically completes the precise docking with the ship's flange. The operation time is shortened by more than 60% compared with traditional manual operation. In addition, the application of digital twin technology can realize real-time simulation of operating status and fault prediction by building a virtual model of the equipment, greatly improving equipment operation and maintenance efficiency.
With the acceleration of global energy transition, LNG demand continues to grow, and the technical requirements for low-temperature loading arms are constantly improving. In the future, LNG loading arms will develop towards larger diameter, higher intelligence, and better thermal insulation performance. Through technological innovation, they will promote the safe and efficient development of the LNG industry and provide strong support for clean energy substitution.
