In the fields of liquefied natural gas (LNG) storage and transportation and cryogenic engineering, the performance of insulation materials directly affects the safety, energy efficiency, and operational stability of the system. LNG elastic felt, as a flexible insulation material specifically designed for cryogenic conditions, is widely used in cryogenic pipelines, equipment, and storage and transportation systems. This article will systematically explain the cryogenic insulation principle of LNG elastic felt, starting from its material structure and heat transfer mechanism.

I. Overview of the Material Properties of LNG Elastic Felt

LNG elastic felt is typically made from high-performance inorganic fibers or composite fiber materials through a special process, possessing excellent flexibility and cryogenic adaptability. It maintains structural stability even at low temperatures, and is not prone to embrittlement or pulverization.

From an application perspective, LNG elastic felt is mainly used for:

LNG cryogenic pipeline insulation

External cold insulation systems for cryogenic equipment

Liquefied gas transportation and storage facilities

II. Core Objectives of Cryogenic Insulation

In LNG operation, the insulation system needs to achieve the following objectives:

1. Reduce heat transfer from the outside environment to the cryogenic medium

2. Reduce evaporation loss of the medium

3. Control frost and condensation on pipeline or equipment surfaces

4. Improve the safety and stability of system operation

LNG elastic felt is designed with these objectives in mind in its structure and performance.

III. Overview of the Cryogenic Insulation Principle of LNG Elastic Felt

The cryogenic insulation principle of LNG elastic felt is mainly formed by the combined effect of the following aspects:

Inhibiting solid heat conduction

Limiting gas convection heat transfer

Reducing heat radiation transfer

The buffering effect of structural flexibility on cryogenic stress

These mechanisms work synergistically to maintain good insulation performance even in extremely low temperature environments.

IV. The Inhibiting Effect of Fiber Structure on Low-Temperature Thermal Conductivity

1. Interlaced Fiber Structure Extends Heat Transfer Path

The interior of LNG elastic felt consists of a porous structure formed by numerous randomly interlaced fine fibers. When heat is transferred within the material:

It needs to continuously circulate around the fiber structure

The heat transfer path is significantly lengthened

The amount of heat transferred per unit time is effectively reduced

This is a crucial basis for its low thermal conductivity.

2. Controlled Solid Heat Transfer Ratio

In the elastic felt structure, the solid fibers are not a continuous, dense structure; the solid heat transfer channels are dispersed, which helps reduce the overall thermal conductivity.

V. The Role of the Static Gas Layer in Low-Temperature Insulation

A large amount of gas exists within the pores of LNG elastic felt. When this gas is confined within a small space:

Natural convection is difficult to form

Heat mainly relies on molecular conduction

Due to the low thermal conductivity of gases, this "static gas insulation layer" plays a crucial role in low-temperature insulation.

VI. Control Mechanism for Heat Radiation Transfer

In cryogenic environments, heat radiation remains a significant heat transfer mechanism. LNG elastic felt typically reduces radiative heat transfer through the following mechanisms:

Multi-layered structure for multiple reflections of radiative energy

Dispersion and absorption of radiative heat by the material surface

This reduces the amount of external heat entering the cryogenic system via radiation.

VII. Advantages of Flexible Structures in Cryogenic Conditions

1. Buffering Thermal Expansion and Contraction Stress

In cryogenic environments, pipelines and equipment experience significant thermal expansion and contraction. The flexible structure of LNG elastic felt can:

Absorb deformation stress

Reduce the risk of insulation layer cracking

Maintain insulation continuity

2. Ensure Long-Term Stability of Insulation Layer

During repeated cryogenic cycles, the elastic structure helps the material maintain its integrity, thus maintaining long-term stable insulation performance.

Overall, the cryogenic insulation principle of LNG elastic felt is a composite insulation system composed of a porous fiber structure, a static gas insulation layer, radiative heat transfer control, and a flexible structure. This structural design enables it to effectively reduce heat transfer in extremely low-temperature environments, ensuring the safe and efficient operation of the LNG system.