WO2006034653A1

WO2006034653A1 - Carbon fiber composite for repairing and reinforcing pipelines having defects and the method of application

Info

Publication number: WO2006034653A1
Application number: PCT/CN2005/001607
Authority: WO
Inventors: Minxu Lu; Yufang Zhang; Shaohua Dong; Aitian Ge; Yingfeng Chen; Baorui Li; Guoan Zhang
Original assignee: University Of Science & Technology Beijing
Priority date: 2004-09-30
Filing date: 2005-09-29
Publication date: 2006-04-06
Also published as: CN1276024C; CN1616546A

Abstract

The material for repairing and reinforcing metal pipelines, especially pipelines having defects and the method for repairing and reinforcing pipelines having defects with this material are provided. The said material for repairing and reinforcing comprises: (1) a layer of patching adhesive which can be used to fill and patch the defects outside the pipelines, (2) a layer of carbon fiber sheets which have been impregnated or coated with impregnating adhesive and can be employed in the areas of the defects in order to restore and enhance the bearing-strength of the pipelines, and (3) a layer of preservation material which can be applied to the outside surface. The specific strength and the specific modulus of the inventive reinforcing material which may be combined with the pipelines and form an integration so as to support the pressure in the pipelines may be close to those of the metal pipelines so that the bearing-capacity of the final combined patching-layers can be the same as or even superior to the bearing-capacity of the original pipelines. The method of the present invention may be simple and be advantageous that tight joints can be obtained between the reinforcing material and the pipelines and between the reinforcing-layers, furthermore reinforcing operation can be carried out in the case of normal running of the pipelines.

Description

Carbon fiber composite material and method for repairing and repairing defective pipelines

The invention relates to a technology for repairing and reinforcing a defect-containing pipeline, in particular a metal pipeline, by using a resin-based carbon fiber composite material, and more particularly, the invention relates to a reinforcement for repairing and reinforcing a pipeline containing defects, in particular, a pipeline containing defects The material is a resin-based carbon fiber composite material, a method for repairing and reinforcing pipeline defects by the material, and the application of the material and method in repairing and reinforcing defects of oil and gas transmission pipelines.

Background technique

Oil and gas pipeline transportation is one of the five major transportation industries. At present, China's oil and gas long-distance pipelines have reached more than 30,000 kilometers. During long-term service, these pipelines are affected by formation pressure, soil corrosion, galvanic corrosion, external force damage, etc., causing accidents such as pipe bursts and leaks, which affect the normal transportation of pipelines. There are often oil and gas pipeline blasting and leakage accidents at home and abroad. For example, in 1989, there were 1024 casualties in the Ural gas pipeline of the former Soviet Union. In North America, a 13-kilometer accident occurred in the gas pipeline. A large number of on-site investigations have shown that more than 60% of the oil and gas pipelines in service in China have entered the accident-prone period. In general, defective oil and gas pipelines often draw down the pressure-receiving process during operation, which not only affects normal production operations, but also greatly increases operating costs. Therefore, the development of a reinforcing material and method that is effective and easy to implement is a goal pursued in the art. Among the existing oil and gas pipeline external defect repair and reinforcement technologies, there are mainly methods such as traditional welding repair and composite reinforcement. Due to the possibility of weld penetration and hydrogen embrittlement during the entanglement process, it is generally recommended not to use this method for non-stop gas pipelines. The resin-based composite material has been used by foreign oil companies for pipeline reinforcement because of its excellent properties such as light weight, high strength, corrosion resistance, durability, easy construction, and no impact on the appearance of the structure. For example, the composite material reinforcement technology of American Clockspring Company is a composite sheet of isophthalic acid unsaturated polyester and E-glass fiber, which is wrapped on the surface of metal pipe by dry laying, between layers. Bonded with an epoxy adhesive. There are two disadvantages of this technology: First, during the construction process, there is no guarantee that the composite sheet and the tube body, the composite sheet layer and the layer are closely adhered; the other is the elastic modulus and strength of the glass fiber. Low, so the thickness of the reinforcing layer will be thicker, which will cause certain difficulties for subsequent corrosion protection, and the improvement of the bearing capacity of the substrate is also limited.

In recent years, there have been some reports on the use of carbon fiber for the reinforcement of damage to metal pipes outside the pipeline. However, no specific implementation is disclosed.

Carbon fiber is known for its high strength and high modulus of elasticity, and is most suitable for use as a reinforcing material. Table 1 shows the performance comparison of carbon fiber cloth, carbon fiber resin composite material and X60 pipeline steel.

Table 1 Comparison of properties of carbon fiber, carbon fiber composite and X60 pipeline steel

As can be seen from Table 1, the use of carbon fiber as a reinforcing material has the following advantages:

1. The elastic modulus of the resin-based carbon fiber composite is equal to or greater than 210Gpa, which is very close to the elastic modulus of steel 207GPa, which is very beneficial to the co-deformation of carbon fiber composite and steel, which is beneficial to the load between steel and carbon fiber composite. Evenly distributed, which is beneficial to achieve the reinforcing effect. Resin-based carbon fiber composites have a sufficient amount of deformation greater than 1.4%. In general, the deformation of the pipe body is much smaller than the deformation of the carbon fiber composite material, and the reinforcement using the carbon fiber composite material is sufficiently safe from the viewpoint of the deformation of the pipe body.

The strength of carbon fiber reinforced materials is an order of magnitude greater than that of glass fibers, which allows thinner carbon fiber composites to achieve the reinforcement of thick glass fiber reinforced materials.

The object of the present invention is to develop a new technology for using carbon fiber for reinforcing pipelines, especially metal pipelines. The specific strength and specific modulus of the reinforcing materials used are close to the metal pipe materials, and the construction process is simple, and Conducive to the tightness between the reinforcing material and the pipe body, between the reinforcing layer and the layer Tight fit, it can be integrated with the pipe to jointly carry the pressure inside the pipe, and the ultimate composite repair layer can meet the pressure capacity of the original pipe. The technology of the invention can carry out the reinforcing operation without stopping the pipeline, does not require large mechanical lifting equipment during the construction process, does not need welding or cutting pipelines, has low construction space requirements, and has corrosion resistance, aging resistance, etc. advantage.

Summary of the invention

SUMMARY OF THE INVENTION An object of the present invention is to provide a resin-based carbon fiber composite material for repairing and reinforcing a defective pipe, particularly a metal pipe, comprising a carbon fiber sheet and a special resin of the present invention.

Another object of the present invention is to provide a reinforcing material for repairing and repairing a defect-containing pipe, the material comprising a plurality of layers of the resin-based carbon fiber composite material, and one or more of the resin-based carbon fiber composite materials. Extra-layer anti-corrosion material.

The term "pipe" as used herein refers to pipes made of various materials, particularly metal pipes, such as steel pipes.

The term "carbon fiber sheet" as used herein includes carbon fiber sheets made of various raw materials, such as carbon fiber cloth. Preferably, the carbon fiber sheet used in the present invention has a modulus of elasticity in the range of

(1.0-3.0) X 10 ⁵ MPa, tensile strength range of 2500~3500Mpa, elongation δ range of 0. 2-3. 0%, weight per unit area ranging from 200 to 300g/m ² .

The term "resin-based carbon fiber composite material" as used herein refers to a material in which a carbon fiber and a resin are composite-cured.

The material for repairing and reinforcing the defect-containing pipe of the present invention comprises a resin-based carbon fiber composite material and an outer anti-corrosion material. The resin-based carbon fiber composite material includes a carbon fiber sheet and a special supporting resin.

The special accessory resin of the invention comprises two kinds of repair glue and adhesive glue. The repairing glue is used for the filling and repairing of the damage defects outside the pipeline; the adhesive dipping is used for infiltrating the carbon fiber sheet, and the bonding between the carbon fiber and the pipe body and between the carbon fiber sheets. Repair glue and adhesive dipped rubber can be divided into winter and summer. Winter and summer formulations are slightly different and can usually be achieved by adjusting the amount of curing accelerator. When the ambient temperature is lowered, the amount of the curing accelerator can be appropriately increased. Those of ordinary skill in the art, based on common knowledge in the art, or by simple experimentation, know that at a certain use temperature, 7 repair glue

The repairing glue consists of two components, A and B. The ratio of the two components is 2:1.

A component includes:

(A): 30% to 50% by weight of liquid bisphenol A type epoxy resin,

(B) : 10%~20% by weight of liquid novolac epoxy resin

(C): 5% to 10% by weight of fumed silica, and

(D: 35% to 40% by weight of wollastonite or alumina filler;

Part B includes:

(E): 60% to 80% by weight of a modified amine epoxy curing agent, and

(F): 20% to 40% by weight of a promoter 2, 4, 6-tris(dimethylamino)-methylphenol;

The curing agent of (E) in the component B may be, for example, a modified aliphatic amine such as diethylenetriamine glyceryl n-butyl ether (e.g., commercial 593) or a phenolic modified polyamine (e.g., commercial T31).

The properties of the two components A and B which constitute the defect filling and repairing adhesive are as shown in Table 1.

Table 2 Specifications and performance of repair adhesive

The repairing glue can be prepared by mixing and storing the components A and B of the matching resin separately. Weigh accurately according to the specified ratio before use, put it into the container, and mix it with a stirrer. The amount of glue applied should be used up within the available time.

Adhesive

The adhesive dipping consists of two components, A and B. The ratio of the two components is preferably (3~4): 1. A component includes:

(A): 68%~84% by weight of liquid epoxy resin,

(B) : 10% to 15% by weight of acrylate liquid rubber,

(C): 5% to 15% by weight of fumed silica, and

(D) : 1% to 2% (by weight) of pigment;

Part B includes:

(E): 70% to 90% by weight of a modified amine epoxy curing agent, and

(F): 10% to 30% by weight of an epoxy curing accelerator 2, 4, 6-tris(dimethylamino)-methylphenol;

The epoxy resin of the component (A) may be a bisphenol A epoxy resin or a vinyl modified epoxy resin; the curing agent of the component B (E) may be a modified aliphatic amine such as diethylene. Triaminoglycerin n-butyl ether (e.g., commercial 593) or phenolic modified polyamine (e.g., commercial T31).

The properties of the two components A and B which constitute the adhesive are cured as shown in Table 2.

Table 3 Specifications and performance of adhesive dipped

Item Adhesive

LZ300W (Winter) LZ300S (Summer)

Proportion of component A and B (3-4): 1

Applicable temperature ' C 5-15 15-35

Available time (min) 40-170 60-180

Finger touch drying time (hr) 4.0-12.0 3.0-10.0

Shape creamy

Performance index Tensile strength Bending strength Compressive strength Steel shear strength Elastic modulus

(Mpa) (Mpa) (Mpa) degrees (Mpa) (Mpa)

30 40 50 ^10 ^2X10 ³ main use to coat the surface of steel pipe, infiltrated carbon fiber sheet The adhesive dipping can be prepared as follows: the components A and B of the matching resin are separately mixed and stored, accurately weighed according to the prescribed ratio before use, and then placed in a container, and uniformly mixed with a stirrer. The amount of glue applied should be used up within the available time. Specifically, the resin-based carbon fiber composite material for repairing and reinforcing the defect-containing pipeline of the present invention comprises the following materials:

1. A repairing rubber layer for filling the surface defects of the pipeline;

2. A multi-layer carbon fiber sheet in which a carbon fiber sheet is coated with a glue dipped, and the carbon fiber sheet layers are alternately laid at an angle as needed.

The present invention also provides a reinforcing material for repairing and repairing a defect-containing pipe, the material comprising a plurality of layers of the resin-based carbon fiber composite material, wherein each layer of the resin-based carbon fiber composite material is placed along a radial or circumferential direction of the pipe, Adjacent two layers of composite material may be laid in parallel, perpendicular or at an angle.

The reinforcing material also includes a multilayer outer anticorrosive material located outside of the resin-based carbon fiber composite. The outer anticorrosive material is in principle the same as the original outer anticorrosive material that needs to be reinforced. A commonly used external anti-corrosion material is a polyethylene cold-wound adhesive tape, and the thickness of the polyethylene adhesive tape is 0.7mn! ~ 2.0mm is suitable; tensile strength is better than ISMpa.

In practical applications, according to the specific conditions of pipeline defects, the skilled person can determine the thickness, width and amount of reinforcing material according to the usual defect reinforcement parameter design method. Another object of the present invention is to provide a method for repairing and reinforcing a defective pipe, particularly a defective metal pipe, using the material of the present invention, which has good construction safety and performance superiority.

Another object of the present invention is to provide a repairing and reinforcing material and method for damage defects outside the oil and gas pipeline, that is, a technique for repairing and reinforcing the damage of the oil and gas pipeline by using the materials and methods described above.

The method for repairing and repairing a pipeline, such as an external damage defect of an oil and gas metal pipeline, using the material of the present invention includes the following steps:

1. Surface cleaning of the pipeline;

2. Repair the defects on the pipe surface Depressing the surface of the pipe, such as honeycomb, pockmark, small hole, near the weld, etc., with a repairing rubber, and repairing to a smooth surface;

3. Wet paste carbon fiber cloth

The carbon fiber cloth is pasted according to a certain size and number of layers, and the resin-based carbon fiber composite material layers are placed along the radial or circumferential direction of the pipe as needed, so that the adjacent two layers of the composite material are parallel, perpendicular or at an angle. Staggered laying. Wherein the carbon fiber cloth is brushed or impregnated with the adhesive of the present invention;

4. Anti-corrosion repair of the work area

The surface of the bonded carbon fiber composite material is entangled with a polyethylene cold wrap tape.

Before implementing the method, the pipe must be surface-cleaned first, and the surface of the pipe, such as honeycomb, pockmark, small hole, near the weld, etc., should be repaired with a repairing glue, that is, the repaired putty is smoothed and smoothed, and the surface is smoothed to the surface. If there are still irregularities, it should be smoothed with sandpaper.

The carbon fiber cloth is pasted by wet bonding, that is, the carbon fiber cloth is first brushed or impregnated with the epoxy resin adhesive of the present invention, and then entangled and reinforced. In order to ensure the construction quality, the longitudinal and transverse overlap of the carbon fiber sheets should be kept to a certain length.

The anti-corrosion repair of the work area should be carried out after the adhesive surface of each adhesive surface in the reinforcing work area is dried. The overlapping width of the wound layer and the original anti-corrosion layer should be kept a certain length. When wrapped around 3⁄4, the edges of the tape should be parallel and should not be twisted.

In order to ensure the construction quality, when excavation and backfilling are required, it should be carried out in accordance with the required construction requirements. For example, for on-site inspection of identified defect locations, manual excavation must be performed under the supervision of on-site guardians. Pay attention to the measurement of the buried depth during the excavation process to prevent the iron from damaging the anti-corrosion layer and the steel pipe. After the reinforcement construction is completed and it is confirmed that there is no leakage point in the excavation pipe section, the sand or plain soil is used for stratified solid backfilling, and the site is cleaned and the original appearance is restored to ensure that the buried depth of the pipeline meets the design requirements.

The materials and methods of the present invention are described in detail below with reference to the accompanying drawings.

DRAWINGS

Fig. 1 is a schematic diagram of a pipe and a defect for a blasting test, in which a defect is a part for repairing and reinforcing, and a defect is a part for comparison without repairing and reinforcing.

Figure 2 is a pressure-time diagram of the hydraulic burst test. 01607 Figure 3 is a photograph of the shape of the reinforcing part in the burst test. It can be seen from the photograph that the pipe on both sides of the reinforcing part under pressure is bulged, and there is no change in the reinforcing part.

Fig. 4 is a photograph showing the appearance of the mechanical scratch of the pipe of the embodiment 2.

Fig. 5 is a photograph showing the appearance of the defect of the external force of the pipe of the embodiment 2.

Figure 6 is a photograph of the appearance of the pipe after repairing in Example 2.

detailed description

In order to further illustrate the materials and construction techniques of the present technology, the following examples are given. However, the examples are not intended to limit the scope of the invention in any way.

Example 1 : Evaluation of the technical solution of the present invention by a water blasting test method

In order to test the implementation effect of the technology, the Φ660 gas pipeline is taken as an example to simulate the defect size that may exist in the gas pipeline, and the technology is evaluated by the water pressure burst test method. The test tubes and defects are shown in Figure 1. The test process is as follows:

Take a pipe of the same size and material as the main pipe of a gas pipeline, 5.45m (the pipe is X60 spiral welded pipe, the pipe diameter is 660mm, the wall thickness is 8.7mm, the design working pressure is 6.4Mpa), and the ends are reserved. The vent hole and the inlet hole are sealed (see Figure 2).

Clean the pipe parts that need to be reinforced to remove the anti-corrosion layer, epoxy coating and dirt on the outer surface of the pipe, and make the surface treatment quality reach the St3 level specified in GB/T8923-1988.

A defect of 50 mm X 30 mm X 4 mm (defect 1) was made at the portion where the anti-corrosion layer was peeled off, and the defect was repaired and reinforced by the technique of the present invention (see Example 2). For the convenience of the test, a defect of 50 mm X 30 mm X 2.0 mm (defect 2) was made in another part of the test tube, and this defect was not reinforced.

The test tube is filled with water and vented, and when the test sample is filled with water and does not leak, the pressure is gradually increased until the sample is broken. The pressurization process is shown in Figure 2. The results of the blasting test show that: the damage is generated at the small defect (defect 2) which is not repaired and reinforced, and the damage is typical tear-type damage; the test tube has obvious expansion phenomenon, and the repaired and reinforced defect There is no obvious change at the place. Under the pressure, the test tube on both sides of the reinforcing part is bulged, resulting in obvious expansion (see Figure 3). The blasting pressure of the reinforced tube is 16.4Mpa, which is much higher than the design work of the sample. The pressure (6.4 Mpa) indicates that the technology has reached the goal of reinforcement. Example 2: Repair and reinforcement of natural gas pipeline defects 01607 The field embodiment of the present invention is an example of defect reinforcement applied to the Shaanxi-Beijing gas pipeline. The defect is reinforced by the reinforcing material and the repair and reinforcement method according to the present invention. The specific implementation process is as follows:

1. Excavation and surface cleaning of the pipeline

The defect of reinforcement construction is located somewhere in Shaanxi section of Shaanxi-Beijing pipeline. It is located at the edge of the desert. It is a sandy soil structure. The surface water layer is shallow. The depth of the pipeline is about 1300mm, and the surface temperature of the tube is about 40°C. There are three mechanical damages in the pipe body. One is an obvious mechanical scratch, 150mm long, 3.5mm deep, 20mm deepest at the deepest point (see Figure 4); the other two are bumps, 1.5mm deep and 20mm long (see Figure 5).

The surface cleaning of the pipeline, for example, the result of surface treatment should be such that the quality of the pretreatment of the base layer reaches the St3 level specified in the national standard GB/T8923-1988.

2. Repair the pipeline

For repairing the surface defects of steel pipes such as honeycombs, pockmarks, small holes, welds, etc., repairing the putty with a putty, repairing the surface to a smooth surface, and still having irregularities on the surface, it should be smoothed with sandpaper. The formulation and dosage of the repairing glue are shown in Table 4.

3, using wet method to paste carbon fiber cloth

Firstly, the adhesive preparation and the repairing glue are prepared according to the preparation method described above and the formulation described in Table 3, and then the epoxy resin adhesive is applied to the carbon fiber cloth (the amount of the adhesive is shown in Table 3), and the same is used. Wound reinforcement.

7 Table 3 Reinforcing materials and dosage

The number and direction of winding of the carbon fiber cloth are two layers in the circumferential direction, one in the axial direction, two in the circumferential direction, one in the axial direction, and two in the circumferential direction, and a total of eight layers.

4. Anti-corrosion repair of the working area

The anti-corrosion repair should be carried out after the adhesive surface of each adhesive surface in the reinforcing work area is dried. The outer anticorrosive material used is a polyethylene adhesive tape wrapped around one layer. The overlapping width of the wound layer and the original anti-corrosion layer should be not less than 100 mm. The length of the adhesive tape at the beginning and end of the adhesive tape shall be not less than 1/4 of the pipe circumference and not less than 100 mm. When entangled, the edges of the adhesive tape should be parallel and the wrinkles should not be twisted.

The shape of the pipeline after repairing and repairing is shown in Figure 6

The pipe segment described in this embodiment has been below the design working pressure due to the existence of the defect. N2005/001607 operation, which invisibly increases the running cost of the pipeline; after the repair and reinforcement, the operating pressure can be increased to the design level.

In summary, the present invention is a new matching technology suitable for pipeline repair and reinforcement, and is suitable for damage of damaged pipelines caused by corrosion, mechanical or other reasons for different pipe diameters. The construction process does not require pipeline shutdown, and the reinforcing material can be tightly wrapped around the pipeline, which has little effect on the increase of the pipeline's own weight. It can be integrated with the pipe to jointly carry the pressure inside the pipe and make the pressure capacity of the repaired pipe reach and exceed the pressure capacity of the original pipe.

The embodiments of the present invention have been described in detail above, and it is obvious to those skilled in the art that many modifications and changes can be made without departing from the spirit of the invention. All such changes and modifications are within the scope of the invention.

Claims

Rights request

1. A resin-based carbon fiber composite material for repairing and repairing a defect-containing pipe, comprising a carbon fiber sheet coated or impregnated with a viscous glue, wherein the viscous glue is composed of two components, namely, A and B, wherein

A component includes:

(A): 68%~84% by weight of liquid epoxy resin,

(B) : 10%~15% by weight of acrylate liquid rubber,

(C): 5% to 15% by weight of fumed silica, and

(D): 1% to 2% by weight of pigment;

Part B includes:

(E): 70% to 90% by weight of a modified amine epoxy curing agent, and

(F) : 10% to 30% by weight of an epoxy curing accelerator 2, 4, 6-tris(dimethylamino)-methylphenol;

The epoxy resin of component A (A) may be bisphenol A epoxy resin or vinyl modified epoxy resin; the curing agent of component B (E) may be modified aliphatic amine;

The two components A and B were uniformly mixed with a stirrer in a ratio of (3 to 4): 1 before use.

2. The resin-based carbon fiber composite material according to claim 1, wherein said material further comprises a repairing glue for filling out defects outside the pipe, said repairing glue comprising two components of A and B, wherein the component A comprises:

(A) : 30% to 50% by weight of liquid bisphenol A type epoxy resin,

(B) : 10%~20% by weight of liquid novolac epoxy resin

(C): 5% to 10% by weight of fumed silica, and

(D): 35% to 40% by weight of wollastonite or alumina filler;

Part B includes:

(E): 60% to 80% by weight of a modified amine epoxy curing agent, and

The curing agent of (E) in the component B may be a modified aliphatic amine;

The two components A and B were uniformly mixed with a stirrer in a ratio of 2:1 before use.

The resin-based carbon fiber composite material according to claim 1 or 2, wherein the carbon fiber sheet has a modulus of elasticity E ranging from (0.5 to 20.0) x 10 ⁵ MPa, and a tensile strength S _{b is} in the range of (0.5 to 20.0). X 10 ³ MPa, the elongation δ ranges from 0.1 to 5.0%.

The resin-based carbon fiber composite material according to claim 3, wherein said modified aliphatic amine is diethylenetriamine glycerol n-butyl ether or phenolic modified polyamine.

5. A reinforcing material for repairing and reinforcing a defect-containing pipe, the material comprising the resin-based carbon fiber composite material according to any one of claims 1 to 4, wherein the resin-based carbon fiber composite material of each layer is radially along the pipe Or placed in a hoop, the adjacent two layers of composite material may be parallel, perpendicular or staggered at an angle.

6. The reinforcing material of claim 5 wherein said reinforcing material further comprises one or more outer anticorrosive materials located outside of the resin based carbon fiber composite.

7. The reinforcing material of claim 6 wherein said outer anticorrosive material is a polyethylene adhesive tape.

8. A method of repairing and reinforcing a defective pipe using the material of any of claims 1-7, the method comprising the steps of:

(1) repairing defects on the surface of the pipe by the repairing glue according to claim 2, and repairing the surface to a smooth surface;

( 2 ) Wet-bonded carbon fiber sheet

The carbon fiber sheet is pasted according to a certain size and the number of layers, the carbon fiber sheet is coated with the adhesive dipped according to claim 1, or impregnated with the adhesive dipped, and the carbon fiber sheet layer is along the pipeline as needed. The radial or circumferential placement, adjacent two layers of carbon fiber sheets may be parallel, perpendicular or staggered at an angle.

9. The method according to claim 8, further comprising the step of preserving the work area, the step comprising: cold-wrapping the polyethylene with a certain size and number of layers on the outer surface after the carbon fiber sheet is pasted The tape is wrapped around it.

10. A method according to claim 8 or claim 9, further comprising surface cleaning the damaged portion prior to repairing the conduit.