Contact: Cheng Huiqiang
Address：No. 333, Jinxian Road, Jinjiaba, FENHU Town, Wujiang District, Suzhou City, Jiangsu Province
Abstract: Combined with the application of cold-wrapped tape in the overhaul of anti-corrosion layer of oil pipelines in Northeast China, the problems existing in the process of cold-wrapped tape are put forward. The product classification, surface treatment, insulation performance and service life of cold-wrapped tape in the overhaul of pipeline anticorrosive layer were analyzed and discussed. The adaptability of cold-wrapped tape in the overhaul of pipeline anticorrosive coatings was studied. (Anticorrosive tape)
Keywords: pipes, cold-wrapped tape, overhaul of anticorrosive coating, applicability
Most of the oil pipelines in Northeast China were built in the 1970s. The pipelines used petroleum asphalt glass cloth anti-corrosion coatings. After more than 30 years of use, the performance of the anti-corrosion coatings has decreased significantly. For this reason, cold-wrapped tape was used as the anti-corrosion material, and the anti-corrosion layer of the pipeline was successively overhauled to ensure the safe operation of the Northeast oil pipeline. The follow-up test results show that after the pipe anticorrosive coating is overhauled, the cold-wrapped tape has wrinkles, and the insulation performance is significantly reduced. Therefore, it is necessary to discuss its applicability in the overhaul of pipeline anticorrosive coatings.
I. Existing problems
The northeast oil pipeline is a hot oil pipeline, which is heated and transported at an operating temperature higher than 33 ° C. The overhaul of the anticorrosive layer adopts the non-stop ditch operation method. Due to thermal and stress conditions, continuous large-scale excavation has not been performed; the working space is narrow, and manual removal and solvent (diesel) are mostly used to remove the old coating, and electric wires are used. Brush or angle grinder for surface treatment, construction with semi-mechanical winding machine.
一分彩1. Types and problems of cold-wrapped tapes
一分彩There are mainly two types of cold-wrapped tapes used in the overhaul of the anti-corrosion layer of Northeast oil pipelines. One is a composite anti-corrosion tape (polyethylene cold-wrapped tape) that is made of polyethylene and butyl rubber as the main raw material and is heat-melted and laminated. ); The other is a high-strength polypropylene fabric as a substrate, coated with a certain thickness of high-viscosity rubber-modified asphalt polypropylene reinforcement fiber cold-wrapped anticorrosive tape (polypropylene cold-wrapped tape). During the overhaul of the pipeline anticorrosive layer, these two types of cold-wrapped belts have the advantages of simple construction, short backfilling intervals, no pollution, and safety and harmlessness.The construction technology is more suitable for pipeline anticorrosive overhaul, but during construction and subsequent follow-up investigation The following problems remain during the process.
一分彩(1) The two kinds of cold-wrapped tapes are unevenly overlapped, with empty drums or air bubbles.
(2) There are axial folds of the two types of cold-wrapped strips below the centerline of the pipeline, especially in clay areas. Polyethylene cold-wrap folds are relatively large.
一分彩(3) Polyethylene cold-wound tape has low adhesion to the pipe body, and the adhesion performance is unstable.
一分彩(4) Polypropylene tape has low hardness and low resistance to impact and compression damage. Under impact and compression pressure, it is easy to produce dents; its insulation performance will decrease after a long period of burial.
一分彩(1) Weak or uneven winding tension can cause defects. Some lightweight winding machines, due to their poor resistance to deformation and high operating requirements, need to be adjusted frequently to prevent uneven tension, hollow drums, or air bubbles during the winding process.
(2) After the overhaul of the anticorrosion layer, the pipelines have various degrees of subsidence. The general settlement amount is 10-20 cm, especially after the long-distance anticorrosion layer is overhauled in the line valve room, on both sides of the road and railway, and before and after the fixed pier. It is easy to cause excessive uneven settlement of the pipeline. Under the action of large settlement stress, the cold-wrapped bands below the centerline of the pipeline are prone to axial wrinkles. If the cold-wrapped bands and the pipe body or cold-wrapped bands have poor adhesion, the wrinkles will become more serious.
(3) Due to the thinness of the polyethylene-based film, the resistance to mechanical damage of the cold-wrapped tape is reduced.
一分彩(4) The softening point of the adhesive layer of polypropylene fiber reinforced material is low, and the hardness is insufficient. Especially when it is used in hot oil pipeline, it is easy to produce pressure depression. In addition, due to the influence of factors such as water absorption of the modified asphalt glue, volatilization of light components, drilling of plant roots, soft rubber layer and susceptibility to compression damage of hard objects, its insulation performance will decrease.
Contact: Cheng Huiqiang
|Contact : Li Cong|
|Address: No. 333, Jinxian Road, Jinjiaba, Wujiang District, Suzhou, Jiangsu|