The LNG double-walled metal tank is like a magnified thermos, with inner and outer metal shells forming a vacuum sandwich. The inner tank directly contacts the -162°C liquefied natural gas and is made of cryogenic materials; the outer tank withstands atmospheric pressure. A vacuum is created between the two tanks, and multiple layers of insulation material are used to effectively block external heat transfer. This design allows LNG to be stored stably at atmospheric pressure, with an evaporation rate controlled below 0.1%.
Safety Secrets in the Structure:
Flexible Support System: A special support structure between the inner and outer tanks allows for thermal expansion and contraction.
Vacuum Maintenance System: Equipped with molecular sieves and a vacuum pump, continuously maintaining the vacuum level in the sandwich.
Leak Monitoring Layer: Gas detection channels are installed in the insulation layer to monitor the seal in real time.
Seismic Design: Optimized support point distribution through mechanical calculations enhances vibration resistance.
Scientific Material Selection: The inner tank uses 9% nickel steel or aluminum alloy, maintaining good toughness even at ultra-low temperatures; the outer tank primarily uses carbon steel, balancing strength and cost. The insulation material in the sandwich layer works like a layered cake: fiberglass cloth reflects radiant heat, perlite powder blocks convection, and aluminum foil composite material reflects thermal radiation. This combination results in a thermal conductivity lower than that of still air, enabling long-term heat preservation.
