As a high-quality, efficient and convenient clean energy and chemical raw material, natural gas has huge application potential. Among them, liquefied natural gas (LNG), which has a high degree of marketization, has also begun to attract attention as a supplement to traditional gas sources.

Since LNG pipelines are typical low-temperature medium transportation pipelines, LNG transported by pipelines is generally in a low-temperature liquid state. Once external heat invades, it will easily vaporize, causing the single-phase liquid flow to change into a gas-liquid two-phase flow, or even a gas lock, resulting in an increase in pressure and a decrease in flow rate in local pipe sections, seriously affecting the normal transportation of LNG. Therefore, the vaporization of LNG must be strictly controlled. However, LNG pipeline insulation can prevent the intrusion of external heat and the vaporization of LNG, and its effectiveness mainly depends on the insulation quality of the LNG pipeline. Therefore, LNG pipelines must adopt thermal insulation measures, and their quality will not only affect the transportation efficiency of LNG, but also have an important impact on the normal operation of the entire system.

LNG pipeline insulation types
Vacuum insulation: The principle is to make the insulation structure into a sealed interlayer, and the internal space is evacuated to a certain degree of vacuum to reduce heat transfer. In the domestic LNG system, it has a long utilization time, obvious thermal insulation effect and small energy loss. However, due to high price and long manufacturing time, it is mostly used in key projects and cannot be used on a large scale.

Stacking insulation: Stacking insulation is a traditional method of insulation, that is, porous insulation materials are installed outside the pipe, and the insulation is achieved because the cells are filled with normal pressure air (or other gases). The thermal insulation effect is slightly lower than that of vacuum insulation, but it has a simple structure, low price, and convenient operation and maintenance. Currently, domestic LNG pipelines mostly use this method for pipeline insulation.

In the current market, the existing stacked insulation materials mostly use polyurethane and foam glass materials according to the different LNG temperatures. Compared with traditional thermal insulation materials such as polyurethane and foam glass, melamine foam has more advantages. Melamine foam has a wide range of weather resistance (minus 196 degrees Celsius to 200 degrees Celsius), maintains a stable physical and chemical structure under high and low temperature conditions, and provides excellent thermal conductivity (thermal conductivity coefficient, 0.032 W/ (m*K))) and sound absorption performance (0.95NRC), light weight, environmental protection and safety make it an irreplaceable LNG pipeline insulation material.

In the engineering design of LNG plant stations, the actual situation of the project should be specifically analyzed, and appropriate thermal insulation and cold insulation materials should be selected and used. Its highlights include:

The minimum safe use temperature of cold insulation materials should be lower than the minimum temperature of the medium during normal operation;
The fire protection performance of cold insulation materials should meet the requirements of current national standards;
Prioritize the use of cold insulation materials with excellent water vapor permeability resistance to ensure long-term stability of material performance;
The cold insulation material should have good on-site cutting or cutting processing performance, easy construction, and simplified on-site installation difficulty;
Give priority to materials or products with high comprehensive economic benefits;
Reduce the amount of daily maintenance work after the cooling system is put into production and improve the reuse of materials.

Based on the above requirements, melamine foam can be used as a thermal insulation and cold preservation material for LNG pipelines, and melamine foam plays an important role in the thermal insulation and cold preservation of LNG pipelines. Melamine foam is a flexible elastomer plastic material with a three-dimensional network structure. It still maintains a complete physical and chemical structure at minus 196 degrees Celsius, so it still has excellent thermal conductivity at low temperatures and inhibits the convection of the inside and outside environments. Conduction and radiation heat conduction, excellent fire resistance (B1, UL94 V0 and HL-1) and insulating properties (does not generate any static and antistatic), acid and alkali resistance, corrosion resistance, aging resistance, light weight and low temperature flexibility, etc. performance, and because melamine resin foam is an elastic but non-fiber material, does not contain any dust, halogenated-free and hydrocarbons-free, flame retardants and/or toxic heavy metals-free, especially suitable for places with particularly high eco-friendly requirements , cold storage (pharmaceutical processing plant, fruit and vegetable preservation processing plant, food processing plant, meat processing plant and cold drink factory) cold insulation (thermal and acoustic insulation), refrigerated/freezer cold insulation (thermal and acoustic insulation), LNG liquefied storage tank cold insulation (thermal and acoustic insulation), LNG liquefied transport vehicle or Ship cold and thermal insulation (thermal and acoustic insulation).

For more information about SINOYQX Melamine Foam, please reach us at [email protected] or voice to us: +86-28-8411-1861.