Anti-corrosion treatment of buried pipelines

Long-distance pipelines and pipelines with forced cathodic protection are not allowed to install insulating flanges and cushions when they emerge from the ground. There are no additional requirements for the flanges and mats used by ordinary buried pipelines when they emerge from the ground. 3. Introduction to cathodic protection technology There are two types of cathodic protection technology: Sacrificial anode cathodic protection and forced current (impressed current) cathodic protection. 　　1) Sacrificial anode cathodic protection technology Sacrificial anode cathodic protection technology uses a metal or alloy with a potential that is more negative than the metal to be protected to be electrically connected to the metal to be protected, and relies on the current generated by the continuous corrosion and dissolution of the metal with a relatively negative potential to protect other metals. advantage: A: The one-time investment cost is low, and there is basically no need to pay maintenance fees during operation. B: The utilization rate of the protection current is high, and no over-protection will occur. C: No interference with adjacent underground metal facilities. It is suitable for factory areas and long-distance pipelines without power supply, as well as small-scale distributed pipeline protection. D: It has the function of both grounding and protection. E: The construction technology is simple and does not require special professional maintenance and management. Disadvantages: A: The driving potential is low, the protection current adjustment range is narrow, and the protection range is small. B: The use range is limited by the soil resistivity, that is, when the soil resistivity is greater than 50Ω·m, it is generally not suitable to use the sacrificial anode protection method. C: In areas with strong stray current interference, especially when affected by AC interference, the anode performance may be reversed. C: The effective cathodic protection life is limited by the life of the sacrificial anode, which needs to be replaced regularly. 2) Forced current cathodic protection technology. Forced current cathodic protection technology is to insert a DC power supply in series with the loop, and with the help of an auxiliary anode, direct current is directed to the protected metal, thereby turning the protected metal into a cathode to implement protection. advantage: A: The driving voltage is high and the cathodic protection current output can be flexibly controlled within a wide range, which is suitable for occasions with a large protection range. B: It is also suitable for harsh corrosion conditions or high resistivity environments. C: When insoluble or slightly soluble auxiliary anodes are selected, long-term cathodic protection can be carried out. D: The protection range of each auxiliary anode bed is large. When the quality of the pipeline anti-corrosion layer is good, the protection range of a cathodic protection station can reach tens of kilometers. E: Complete cathodic protection can also be achieved for pipes with exposed or poor-quality anti-corrosion layers.: A: The one-time investment cost is high, and electricity bills need to be paid during operation. B: During the operation of the cathodic protection system, strict professional maintenance and management are required. C: It is inseparable from external power supply and requires external power supply all year round.: It may cause interference to adjacent underground metal structures. So, sir, what do you want to say about the issue of insulating flanges? Do the pipelines in the station do not require flange insulating gasket materials?: Reinforced phenolic resin, coated with neoprene. Cotton fiber reinforced phenolic resin. CNAF high strength insulation material. Cotton fiber reinforced phenolic resin and nitrile rubber gasket. Glass fiber reinforced epoxy resin and fluororubber gasket. Plastic coated soft iron insulating sleeve material.: Reinforced phenolic resin polyester polyamine insulating bolt pad material: Cotton fiber reinforced phenolic resin Glass fiber reinforced phenolic resin Glass fiber reinforced epoxy resin

Brother guren explained it in detail. Thank you very much. The problem I encountered was the underground sewage pipe in the general chemical plant area. This kind of buried pipeline can avoid electrochemical corrosion problems by using insulating gaskets and insulating bolt sleeves when it comes out of the ground. According to your introduction, does the fact that there are no special requirements in the factory mean that unless the owner makes a special request, no processing is required? ps: Can you provide some relevant literature? I would like to learn more about this knowledge in detail. Thank you!