Different classification, urban gas pipelines: can be classified according to use, laying mode, gas transmission pressure, pipe network shape, pressure level system, etc. Long-distance pipeline: classified into metal pipeline and non-metal pipeline according to material properties. Constitute various urban gas pipeline: including door station or gas plant compressor station, gas storage facilities, pressure regulating device, pipeline, metering device, management facilities, supervisory control system, etc.
The urban gas pipeline network should not only ensure uninterrupted and reliable supply of gas to users, To ensure the safe operation and management of the system, simple maintenance, and should be considered in overhaul or failure, shut off some parts of the pipe without affecting the work of other systems.
Therefore, the town gas pipeline includes natural gas pipeline and liquified petroleum gas pipeline, artificial gas does not need pipeline, so the following description of natural gas pipelines and liquefied petroleum gas pipelines difference.
Liquified petroleum gas pipeline transportation system consists of liquefied petroleum gas tank, pumping station, metering station, intermediate pump station, pipeline and terminal gas storage tank. If the transportation distance is close, the intermediate pumping station can not be set up. Because liquified petroleum gas is easy to vaporize, the pipeline pressure is higher than the liquefied petroleum gas saturated vapor pressure, liquid delivery is maintained. Pipeline transportation is superior to other transportation modes in operating cost and safety reliability.
Characteristics of natural gas pipeline: The pipeline system is a continuous closed transportation system, from transportation, storage to user use, natural gas is in a state of pressure; Because of the small specific gravity of natural gas, the influence of hydrostatic head is much less than that of liquid. When the height difference is less than 200 meters, the hydrostatic heads can be neglected and the route is almost free from the vertical terrain restrictions.
Application Advantage of PE Pipe in Gas Pipeline Transportation Engineering
(1) density: With the increase of density of polyethylene, the rigidity of polyethylene material increases, the tensile strength increases.
(2) temperature: polyethylene is a kind of polymer synthesis material, sensitive to temperature, temperature drop, the tensile strength of polyethylene increased, PE pipe low-temperature brittle temperature up to -80 °C.
(3) flexibility: PE pipe has unique flexibility, easy to move in laying, bending and spread.
(4) Corrosion resistance: PE pipe has good chemical stability, high corrosion resistance to various acids, bases and salts. Therefore, PE pipe does not need to carry out anti-corrosion treatment when buried.
(5) weldability: PE pipe is thermoplastic, with good weldability. The welded joints of PE pipes can withstand axial loads without leakage and disconnection, so the joints and bends do not require anchoring. The construction cost is greatly reduced and the pipe network is more safe and reliable.
(6) sanitation: PE pipe in the production and processing process does not add any toxic additives. The inner wall of the pipe is smooth, no fouling, no bacteria.
(7) Economy: In the application of city and low pressure pipeline, compared with steel pipe, PE pipe has obvious economic advantage, and is reflected in many cities in China.
