Method of pipeline repair without decommissioning

Abstract

FIELD: pipeline engineering.SUBSTANCE: invention can be used in the repair of pipelines, as well as in the repair and reconstruction of reservoirs, high-pressure vessels, i.e., structures made from parts with developed cylindrical surfaces, primarily at the stage of preventive repair of areas with accelerated wear. The method includes cleaning and protecting the surface of the section of the pipeline 1 being repaired from corrosion, installing several thin layers of metal with low corrosion resistance 2 on the surface of the section of pipeline being repaired, installing the split coupling 3 around the section of pipeline being repaired, fastening its parts and feeding a corrosive liquid material into the sub-coupling space.EFFECT: increase in the efficiency of repairs due to the possibility of restoring the load-bearing capacity of the pipeline by increasing the strength and rigidity of the pipeline in the damaged section under various repair and operating conditions, as well as a reduction in the labour intensity of repair.2 cl, 1 dwg

Description

[0001] The invention relates to the field of pipeline operation and can find application in their repair, as well as in the repair and reconstruction of tanks, high-pressure vessels, i.e. structures made from parts with developed cylindrical surfaces, primarily at the stage of preventive repair of areas with accelerated wear.

[0002] There are known variants of the method of repairing pipelines by installing a detachable coupling, for example, [1; 2, pp. 108-114; 3, pp. 18-19], including the operations of cleaning the surface of the pipe, connecting the parts of the coupling, applying a quick-hardening polymer material to fill the defects with a preliminary release of the operating pressure in the pipeline.

[0003] The disadvantage of the known method is the need to relieve the working pressure in the pipeline, which negatively affects the performance of the pumping process.

[0004] The closest technical solutions to the claimed one are variants of the method of repairing pipelines by installing a detachable coupling, including the operations of cleaning the surface of the pipe, installing the coupling, installing end seals to seal the sub-coupling space, pumping a fast-hardening polymer material under pressure into the sub-coupling space, followed by maintaining the pressure until the polymer material hardens, that is, creating counterpressure on the section of the pipeline being repaired, for example, [4-15].

[0005] The main drawback of known methods is the inability to maintain uniform pressure in different areas of the sub-coupling space during the curing process of the polymer material, accompanied by shrinkage of this material. In addition, there are temperature limitations on the curing mode: high viscosity and low curing rate at low temperatures, which makes it impossible to use known methods on pipelines pumping cooled media, and a sharp increase in curing rate at high temperatures (pumping hot water, steam, heated viscous liquids), which may prevent the sub-coupling space from being completely filled and the required uniform back pressure being created.

[0006] The purpose of the invention is to increase the efficiency of repairs by ensuring the possibility of restoring the load-bearing capacity of a pipeline by increasing the strength and rigidity of the pipeline in the damaged section under various repair and operating conditions, as well as reducing the labor intensity of repair work.

[0007] The stated objective is achieved due to the fact that in the method of repairing a pipeline without decommissioning, which consists of cleaning and protecting the surface of the section of the pipeline being repaired from corrosion, installing a split coupling around the section of the pipeline being repaired, fastening its parts, according to the invention, before installing the coupling, several thin layers of metal with low corrosion resistance are installed on the surface of the section of the pipeline being repaired, and after installing the coupling, a corrosive liquid material is supplied into the sub-coupling space.

[0008] The proposed method for repairing a pipeline without taking it out of service is carried out as follows. The section of the pipeline to be repaired is cleaned. A detachable coupling is manufactured. The outer surface of the repaired section of the pipeline and the inner surface of the coupling are treated with anti-corrosion treatment. This can be achieved, for example, by passivation, phosphating, or aluminum spraying. Several thin layers of low-corrosion-resistant metal are installed on the surface of the repaired section of the pipeline, such as sheets or strips of low-carbon steel without a protective coating. The coupling is installed on top, and its parts are joined so that the coupling fits snugly against the previously installed thin layers of metal, pressing them against the pipeline surface.It is advisable to use a welded coupling, as the metal shrinkage after the welds cool will ensure a tighter fit between the coupling and the thin upper metal layer, pressing these layers against the pipeline surface. A corrosive liquid, such as a concentrated sodium chloride solution in water, is injected into the space beneath the coupling.

[0009] The proposed method is explained in Fig. 1.

[0010] Fig. 1 - a drawing explaining the operations of the proposed method for repairing a pipeline without decommissioning, where: 1 - pipeline; 2 - thin layers of metal with low corrosion resistance; 3 - split coupling. The corrosive liquid material is not shown in Fig. 1.

[0011] When a corrosive liquid material comes into contact with thin layers of metal with low corrosion resistance, they oxidize. The volume of metal oxides exceeds the volume of the original metal. This causes the oxides to exert pressure on the inner surface of the coupling and the outer surface of the pipeline section being repaired. This creates back pressure on the pipeline wall, reducing the mechanical hoop stress in the pipeline.

[0012] The total thickness of thin layers of metal with low corrosion resistance is determined based on strength calculation.

[0013] Sources of information

[0014] 1. RF Patent No. 2097646 C1, 1995, F16L 57 / 00.

[0015] 2. Zabela K.A., Kraskov V.A., Moskvich V.M., Soshchenko A.E. Safety of pipelines crossing water obstacles - M.: OOO Nedra-Business Center, 2001. - 195 p: ill.

[0016] 3. Guidance document Instructions for the repair of pipelines and tanks using polymer adhesive compositions RD-39-30-968-83, - M. 1984.

[0017] 4. RF Patent No. 2104439 C1, 1998, F16L 55 / 175.

[0018] 5. RF Patent No. 2213289 C2, 2003, F16L 55 / 175.

[0019] 6. RF patent No. 2222746 C2, 2004, F16L 55 / 175.

[0020] 7. RF Patent No. 2292512 C2, 2007, F16L 55 / 175.

[0021] 8. RF patent No. 2352854 C2, 2009, F16L 55 / 175.

[0022] 9. RF Patent No. 2352855 C1 2006 F16L 55 / 18.

[0023] 10. RF Patent No. 2 352 856 C1 2006 F16L 55 / 18.

[0024] 11. Russian Federation Patent No. 2 354 52 C2 2006 B23P 6 / 00 F16L 55 / 17.

[0025] 12. RF Patent No. 2373452 C2 2006 F16L 55 / 18.

[0026] 13. RF Patent No. 2449204 C2 2006. F16L 55 / 175.

[0027] 14. RF patent No. 2449204 C2, 2012, F16L 55 / 175.

[0028] 15. RF patent No. 2451233 C2, 2012, F16L 55 / 175.

Claims

1. A method for repairing a pipeline without taking it out of service, which consists of cleaning and protecting the surface of the section of the pipeline being repaired from corrosion, installing a split coupling around the section of the pipeline being repaired and fastening its parts, characterized in that before installing the coupling, several thin layers of metal with low corrosion resistance are installed on the surface of the section of the pipeline being repaired, which are tightly pressed to the surface of the pipeline by the coupling, and after installing the coupling, a corrosive liquid material is fed into the space under the coupling.

2. The method according to paragraph 1, characterized in that the parts of the coupling are connected by welding.

Images