In liquefied natural gas (LNG) storage and transportation, cryogenic pipelines, and cryogenic equipment systems, the thermal conductivity of insulation materials directly affects energy loss control and system operational safety. LNG elastic felt, as a flexible insulation material specifically designed for cryogenic environments, has its thermal conductivity as a crucial technical indicator for engineering selection. This article will systematically analyze the thermal conductivity of LNG elastic felt from the perspectives of material structure, heat transfer path, and the impact of operating conditions.

I. The Importance of Thermal Conductivity in LNG Insulation Systems

Under LNG operating conditions, the medium temperature is extremely low. If a large amount of external heat is introduced, the following problems will occur:

Increased LNG evaporation loss

Frosting and condensation on pipelines and equipment

Increased system energy consumption

Decreased operational safety

Therefore, insulation materials need to possess stable and low thermal conductivity to continuously prevent external heat from entering the cryogenic system.

II. Overview of Material Properties of LNG Elastic Felt

LNG elastic felt is typically made from inorganic or composite fiber materials using a special process, possessing the following material characteristics:

Dense and uniformly distributed fibers

Good structural flexibility, capable of fitting complex pipelines

Distinct internal porous structure

Suitable for low-temperature and temperature-varying conditions

From a material type perspective, LNG elastic felt belongs to the category of flexible insulation materials for cryogenic insulation.

III. Structural Basis for the Thermal Conductivity of LNG Elastic Felt

1. Interwoven Fiber Structure Inhibits Solid-State Thermal Conductivity

The interior of LNG elastic felt is composed of numerous randomly interwoven fine fibers. When heat is conducted within the material:

It needs to continuously circulate around the fiber structure

The heat transfer path is significantly lengthened

The solid-state thermal conductivity efficiency is significantly reduced

This complex fiber network structure is a key basis for its relatively low thermal conductivity.

2. Gas Insulation in Porous Structures

Elastic felt contains numerous tiny pores filled with stagnant gas:

The gas itself has a low thermal conductivity.

The pore size restricts gas flow.

Gas convection is difficult to form.

This significantly weakens the ability to transfer heat through the gas.

IV. Composition Analysis of Thermal Conductivity of LNG Elastic Felt

From the perspective of heat transfer mechanism, the overall thermal conductivity of LNG elastic felt is mainly composed of three parts:

1. Solid thermal conductivity: heat transfer through the fiber skeleton

2. Gas thermal conductivity: heat transfer through gas in the pores

3. Radiative heat transfer: thermal radiation caused by temperature difference

Through material structure design, LNG elastic felt achieves effective control in all three aspects:

Discontinuous solid structure reduces solid thermal conductivity

Gas is confined in micropores, inhibiting convection

Multi-layer structure weakens radiative heat transfer

V. Main Factors Affecting the Thermal Conductivity of LNG Elastic Felt

1. Density and Fiber Distribution

Within a reasonable range:

The more uniform the fiber distribution

The more stable the structure

The more controllable the thermal conductivity

Too low or too high density will adversely affect the thermal conductivity.

2. Operating Temperature and Temperature Difference Variation

In LNG systems, the material is in a low-temperature state for a long time. LNG elastic felt design must consider:

Stability of thermal conductivity at low temperatures

The impact of temperature fluctuations on material structure

Proper design can ensure minimal changes in thermal conductivity under low-temperature conditions.

3. The impact of moisture on thermal conductivity

Water has a higher thermal conductivity than gas. Once the material absorbs moisture:

Gas in the pores is replaced by water

The thermal conductivity increases

Therefore, in practical applications, LNG elastic felt usually needs to be used in conjunction with moisture-proof and protective structures.

VI. Performance of LNG elastic felt's thermal conductivity in practical engineering

1. Cryogenic pipeline insulation applications

In LNG transportation pipelines, elastic felt, through its stable thermal conductivity, helps to:

Reduce external heat intrusion

Control medium evaporation loss

Maintain stable pipeline operation

2. Cryogenic equipment and storage and transportation systems

In equipment and storage and transportation facilities, the flexible structure of LNG elastic felt can conform to complex surfaces, maintaining good thermal conductivity while reducing thermal bridge formation.

Overall, the thermal conductivity of LNG elastic felt stems from its porous fibrous structure, effective suppression of heat transfer between solids and gases, and excellent adaptability to cryogenic conditions. In LNG cryogenic systems, under appropriate selection and standardized construction conditions, LNG elastic felt can continuously provide stable insulation, offering crucial protection for system energy conservation and safe operation.