The standard specifications for the selection of cryogenic pipelines mainly include the following aspects, which ensure the safe and reliable operation of pipelines in low temperature environments:
1. Low temperature toughness
In a low-temperature environment, the pipe material should have sufficient low-temperature toughness to avoid problems such as embrittlement, cracking or cracking of the material caused by temperature changes. This requires that the mechanical properties such as impact toughness and brittle transition temperature at low temperatures be considered when selecting materials.
2. Corrosion resistance
Low-temperature pipes are often eroded by corrosive substances, so the pipeline materials should have good corrosion resistance. Commonly used materials with good corrosion resistance include stainless steel, aluminum alloy, polyethylene, etc. When choosing, the appropriate material should be selected according to the corrosive characteristics of the environment in which the pipeline is located.
3. Strength requirements
The strength requirement for LNG cryogenic pipelines is to ensure that the pipelines can withstand internal pressure and other external loads during normal operation. This requires that when selecting materials, their strength properties such as tensile strength, yield strength, and compressive strength should be considered. In addition, a stress analysis should be performed to determine the stress distribution and maximum allowable working pressure of the pipeline under different operating conditions.
Fourth, fire performance
For flammable or toxic media, the fire performance of the pipe is particularly important. When selecting materials, their fire resistance limits, combustion rates, and other fire performance should be considered. For specific environments, corresponding fire protection measures should also be taken, such as the use of flame retardant materials, the installation of fire separation, etc.
5. Other requirements
Processability: When selecting a material, it is also necessary to consider its processability for ease of manufacture and installation.
Economy: In addition to meeting the above requirements, the price and availability of materials need to be considered to avoid the risk of exceeding the project budget or pipeline downtime.
To sum up, the standard specifications for the purchase of low-temperature pipelines mainly include low-temperature toughness, corrosion resistance, strength requirements, fire performance, and other requirements such as processing performance and economy. When purchasing, the appropriate pipeline materials should be selected according to the specific engineering environment and requirements, comprehensively considering these specifications.
