Thread Content
Currently, there are many types of anti-corrosion coatings used for steel pipelines in domestic oil and gas transmission (long-distance) projects as well as in urban gas pipeline construction. These include petroleum asphalt, coal tar enamel, epoxy coal tar, cold-applied adhesive tape, sintered epoxy powder, polyethylene, and inorganic zinc-rich + epoxy coal tar anti-corrosion coatings. Since other anti-corrosion materials are widely used in engineering, this section focuses on three types of anti-corrosion methods: sintered epoxy powder, inorganic zinc-rich + epoxy coal tar pitch, and polyethylene. Inorganic zinc-rich compound + epoxy coal tar pitch entered the field of gas engineering applications with the Beijing natural gas double-track project in the North China Oilfield. Mainly used for 1.0MPa high-pressure pipelines. The use of inorganic zinc-rich coatings as a corrosion protection measure for metals has its specific application environments, conditions, and limitations. For the long-term protection of buried pipelines, especially as part of a dual protection system, inorganic zinc-rich coatings are not a good choice. The single-layer sintered epoxy powder spraying anti-corrosion technique is currently recognized internationally as one of the efficient anti-corrosion methods. This anti-corrosion method relies on mechanical and semi-automated assembly lines; the raw materials and manufacturing processes are easy to control. It features a complete set of piping accessories, as well as procedures for repairing leaks and damage, alongside a thorough quality assurance system. Its performance metrics are far superior to those of other common methods, and its advantages become even more evident when dual protection is used. Moreover, its cost is reasonable. At the same time, to ensure the spraying quality of powder coatings, epoxy powders are currently typically those produced by the American company 3M. The polyethylene anti-corrosion technology for buried steel pipelines refers primarily to the technique of obtaining an external anti-corrosion layer for the pipelines through extrusion coating or winding with polyethylene. It was first developed in the early 1950s by the American company Saumel Moore; it features a two-layer jacket structure consisting of an adhesive layer at the bottom and a polyethylene layer on top, and it has gradually been developed and successfully applied in many parts of the world.