Corrosion Prevention of Pipes (2)
Anticorrosion coating is one of the most basic methods of pipeline anticorrosion to apply the coating uniformly and compactly on the surface of the derusting metal pipeline to isolate it from various corrosive media. Since the 1970s, more requirements have been put forward for coating performance by laying pipelines in polar and ocean environments and increasing pipeline temperature due to heating and transportation of oil products. Therefore, more and more composite materials or composite structures are used for pipeline anti-corrosion coatings.
Outer wall anti-corrosion coating: types of outer wall coating materials and conditions of use.
Inner wall anti-corrosion coating: in order to prevent tube corrosion, reduce friction resistance, improve the throughput, and coated in the inner wall of the tube film. Commonly used coatings are amine cured epoxy resin and polyamide epoxy resin, a coating thickness of 0.038 ~ 0.2 mm. In order to ensure that the coating is firmly bonded to the tube wall, the inner surface of the tube must be treated. Since the ’70s tend to tube, outer wall coating selection of the same material, so that the tube, outer wall coating at the same time.
Anticorrosive thermal insulation coating: in the pipeline of medium and small diameter heat transport crude oil or fuel oil, in order to reduce the heat dissipation of the pipeline to the soil, in addition to the composite layer of insulation and anticorrosion outside the pipeline. The commonly used insulation material is hard polyurethane foam plastic, the applicable temperature is -185 ~ 95℃. The material is soft and soft. To enhance its strength, a layer of high-density polyethylene is added to the insulation layer, forming a composite structure to prevent groundwater from seeping into the insulation layer.