In the energy transportation sector, liquefied natural gas (LNG) is playing an increasingly important role. For ease of transport, natural gas is cooled to an extremely low temperature of approximately -162°C, liquefying it and reducing its volume by about 600 times. However, safely and efficiently storing and transporting this "mobile iceberg" places extremely demanding requirements on insulation materials. Among them, LNG resilient felt is a key player in this "insulation battle." So, what exactly is its core performance indicator—the thermal conductivity? What technological secrets lie behind this number?

The Core Answer: A Very Low Numerical Range

Simply put, the thermal conductivity of LNG resilient felt typically ranges from 0.030 W/(m·K) to 0.040 W/(m·K). This range represents the apparent thermal conductivity measured at room temperature (e.g., 25°C).

To give you a more intuitive understanding of this number, consider a comparison: the thermal conductivity of static air at room temperature is about 0.026 W/(m·K), making it an excellent insulator. Ordinary building insulation materials might have thermal conductivity values of 0.035-0.050 W/(m·K) or even higher. The fact that the thermal conductivity of LNG resilient felt can approach or even surpass that of static air fully demonstrates its exceptional insulation performance.

Why is this number so important?

Thermal conductivity is a physical quantity that measures a material's ability to conduct heat. A lower value means better thermal insulation (or cold retention) performance. For an ultra-low temperature liquid like LNG, an extremely low thermal conductivity means:

1. Minimizing Boil-Off Gas (BOG) Loss: Even with top-tier insulation, external heat will slowly seep in, causing a small amount of LNG to evaporate into gas (BOG). Excellent insulation can keep this evaporation rate at a very low level, reducing cargo loss and improving economic efficiency.

2. Ensuring Storage and Transportation Safety: Effective insulation ensures that the temperature of the LNG storage tank structure (such as the ship's steel plates) does not become too low, preventing materials from becoming brittle due to cryogenic temperatures and avoiding surface icing that could lead to safety hazards.

3. Improving Energy Efficiency: Reducing cold loss equates to energy savings, aligning with green and low-carbon transportation principles.

How does LNG resilient felt achieve such excellent insulation performance?

LNG resilient felt is not a single material but a functional composite material system. The secret to its low thermal conductivity lies in a sophisticated combination of factors:

1. Core Insulation Principle: Trapping Static Air. Its main body consists of very fine glass fibers or rock wool fibers, forming an intricate micron-level network structure through a special manufacturing process. This structure traps air within countless tiny, non-convecting cells, thus maximizing the use of air's inherent efficient insulation properties. Heat can only be slowly transferred through the solid fibers and the static air in this structure, following an extremely tortuous path with great resistance.

2. The Ingenuity of "Resilience". Unlike traditional rigid insulation boards, resilient felt has good compression resilience. This allows it to tightly fill the insulation space of LNG storage tanks, especially in complex corners and irregular areas, forming a seamless "sealed" insulation layer. This effectively eliminates "thermal bridging" caused by gaps, preventing localized rapid heat ingress.

3. System Design for Complex Environments. In practical applications, the insulation performance of LNG resilient felt is the result of the entire system working together. It is used in combination with moisture barriers, reflective layers, etc. Particularly under ultra-low temperature conditions, radiative heat transfer within the material becomes significant. Therefore, high-performance LNG resilient felt often incorporates special opacifiers (such as titanium dioxide, carbon black, etc.) to reflect and scatter infrared radiation, further reducing the apparent thermal conductivity under cryogenic conditions.

Conclusion

In summary, the thermal conductivity of LNG resilient felt, stably around 0.035 W/(m·K), is the cornerstone that makes it an ideal low-temperature insulation material. This seemingly simple number represents the deep integration of materials science, thermodynamics, and engineering design. It is not merely a physical parameter but also a guardian ensuring the safe, stable, and efficient operation of the global LNG energy supply chain. The next time we use clean natural gas, we might remember the technological contribution of that thin, resilient "coat."

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