CNG Pipeline and Components
Natural gas pipelines must be constructed using seamless steel pipes. For pipelines with a design pressure of less than 4.0 MPa, they should adhere to the current national standard GB/T 8163, which covers seamless steel pipes for fluid transmission. For pipelines with a design pressure greater than or equal to 4.0 MPa, the pipeline materials should comply with the standards outlined in GB/T 14976 (stainless steel seamless pipes for fluid transport) or GB/T 5310 (seamless steel pipes for high-pressure boilers).
All equipment and pipeline components in the gas station that come into contact with natural gas should be made of materials compatible with the natural gas medium. This ensures the safety and durability of the entire system.
For high-pressure natural gas pipelines within the station, welded connections are recommended. For connections between the pipeline, equipment, and valves, flanged, ferrule, or tapered thread connections are suitable, providing flexibility and strength.
Outdoor natural gas pipelines should preferably be installed underground or in trench systems. When laid underground, the top of the pipeline should be at least 0.5 meters below the surface. In regions prone to freezing, the pipelines should be laid below the frost line. If a trench installation is used, measures must be taken to prevent the accumulation of leaked gas. For indoor pipelines, trench installation is also recommended, and the trench should be filled with neutral sand to prevent corrosion and other damage.
The corrosion protection for buried pipelines must comply with the current national standard GB/T 21447, which provides guidelines for controlling external corrosion of steel pipelines. This ensures long-term protection against environmental factors and enhances the overall integrity of the CNG infrastructure.
