STRUCTURAL CHARACTERISTICS OF NATURAL GAS PIPELINE

Natural gas pipeline is a natural gas (including gas from oil production) mining or processing factory pipelines to the city gas distribution center or industrial enterprise users, also known as gas pipeline. Natural gas pipeline transportation of natural gas, is the only way to transport a large number of natural gas on the land. In the world’s total length of pipelines, natural gas pipelines accounted for about half of the.

Structure characteristics

pipeline structure

The gas pipeline is composed of a single tube by connecting together. The modern gas collecting pipe and the gas transmission pipeline are formed by the connection of the steel pipe through electric welding. Steel seamless tube, spiral seam pipe, straight seam pipe, seamless pipe for pipeline diameter is 529 mm below the spiral seam pipe and straight pipe for large diameter pipeline. In the pipe cross section structure pipeline, complex for internal coating of steel – insulation layer insulation (insulation layer); only simple steel tube and the outer insulating layer, and the inner wall coating and heat (cold) layer are considered gas process coupled with determination.

Piping material

Steel pipe is the main material of pipe. Natural gas transmission steel pipe is the plate (with) through the deep processing of the formation of a special metallurgical products. The structure of pipeline steel, due to the difference of the process technology, there are some differences in the production of pipeline steel. In 1960s, the general use of X52 steel, in 70s the use of X60, X65 steel, X70 steel based 80-90. Foreign gas pipelines have begun to use X80 steel. With the continuous development of pipeline steel research, Canada and other countries have laid the test section of X100 and X120 pipeline steel. For the first time, the X80 grade pipeline steel was used in the test section of the 7.71km for the first time in the pipeline project of the contact line. Up to 4843km of the west east gas pipeline pipeline all used a diameter of X80 1219mm steel grade pipeline steel, the gas pressure increased to 12Mpa. Generally speaking, X80 steel is ferrite and bainite dual phase structure, X100 pipeline steel is bainite microstructure, X120 pipeline steel is ultra low carbon bainite and martensite. Strength, toughness and weld ability are the three most basic quality control indexes for the pipe of natural gas pipeline [4].

Pipeline characteristics

1. The gas transmission pipeline system is a continuous closed transmission system.

2. From transportation, storage to the user, the gas is in a state of pressure.

3. The transportation of natural gas proportion is small, the static head effect is far less than the liquid, the design height less than 200 meters, the static head is negligible, the line is almost not affected by the vertical limit of the terrain.

4. Does not exist in the liquid pipeline water hammer damage.

5. When the accident occurred, the harm is big, and the scope is wide. Once the rupture of the pipeline, the release of energy, long tear length, discharge of natural gas in case of fire, but also easy to cause a fire.