WO2008089663A1

WO2008089663A1 - A method for repairing, reinforcing or enhancing a pipeline by use of basalt fiber composite material

Info

Publication number: WO2008089663A1
Application number: PCT/CN2008/000139
Authority: WO
Inventors: Jinghong Ruan; Xiuyun Wang; Guo Liu; Minxu Lu
Original assignee: Beijing Safetech Pipeline Co., Ltd.
Priority date: 2007-01-18
Filing date: 2008-01-18
Publication date: 2008-07-31
Also published as: CN101206000A; CN101206000B

Abstract

A method for repairing, reinforcing or enhancing a pipeline, especially a metallic pipeline, uses basalt fiber reinforcing material and resin basis material. The intensity, modulus of the reinforcing or enhancing material are close to those of the metallic pipeline to form an unity with the pipeline, so as to make the bearing capacity of the finally produced composite repairing layer equal to or even higher than that of the original pipeline; and the basalt material is one kind of insulating material, so it can improve the pipeline's compatibility with the cathodic protection and the anti-electrochemical corrosion ability.

Description

Method for repairing or reinforcing pipelines with basalt fiber composite materials

The invention relates to a technology for repairing and reinforcing and/or reinforcing a pipeline, in particular a metal pipeline, by using a resin-based basalt fiber composite material, and more particularly, the invention relates to reinforcing and reinforcing a pipeline, in particular a metal pipe. The material is a resin-based basalt fiber composite material, a method for repairing pipeline defects by using the material, and the application of the material and method in the 4 complex reinforcement of oil and gas transmission pipeline defects. 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 caused by formation pressure, soil corrosion, galvanic corrosion, external force damage, etc., causing accidents such as pipe bursts and leaks; or due to increased transportation requirements, existing transmission capacity is insufficient or design capability Insufficient, unable to raise pressure as required; or due to changes in the type of area through which the pipeline passes, and higher safety requirements, these all affect the normal transportation of the pipeline. At home and abroad, there are often oil and gas pipeline paint breaks and leakage accidents. For example, in 1989, there were 1024 casualties in the blasting of the Ural gas pipeline in 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 adopt the method of step-down transportation when operating operations; when the transportation requirements are increased or the pipeline area changes, and the existing conditions cannot be met, most of them are to maintain the existing conditions, and new pipelines are allowed when necessary. . This not only affects normal production operations, but also greatly increases operating costs. Therefore, it is a goal pursued in the art to develop a method for repairing, reinforcing and enhancing pipelines with good effects, high safety and easy implementation. Among the existing oil and gas pipeline external defect repair and reinforcement technologies, there are mainly traditional methods such as welding repair and composite reinforcement. Due to the possibility of weld penetration and hydrogen embrittlement during welding, especially for gas pipelines that are not stopped, it is generally not recommended. 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, simple construction, and no influence on the appearance of the structure. For example, the composite material reinforcement technology of Clockspring of the United States, which is made of a mixture of isophthalic acid unsaturated polyester and E-glass fiber, is wrapped on the surface of the metal pipe by dry laying, and is used between layers. Epoxy adhesive bonding. Disadvantages of this technique There are two: 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 together; the other is that the glass fiber has low elastic modulus and strength, so the reinforcement is strong. The thickness of the layer will be thicker, which will cause certain difficulties for subsequent corrosion protection, and the degree of improvement of the substrate bearing capacity is also limited. The composite material reinforcement technology developed by Beijing University of Science and Technology, etc., needs to be further improved because of the high cost, the inaccessibility of raw materials, and the fact that the carbon fiber precursor is basically completely dependent on imports.

In recent years, there have been no reports on the use of basalt fiber for pipeline repair reinforcement and reinforcement, and to disclose specific embodiments.

Basalt fiber is an inorganic fiber developed by the former Soviet Union. It is a fiber made from natural basalt ore. It has high tensile strength, high modulus of elasticity, good electrical insulation, corrosion resistance and good chemical stability. Excellent characteristics, and can be used at 600 ° C or higher, its performance is better than ordinary glass fiber. Because there is no boron and other alkali metal oxides in the basalt melting process, the manufacturing process of basalt fiber is harmless to the environment, no industrial waste, no harmful gas is emitted to the atmosphere, and it is a new type of environmentally friendly fiber.

Basalt fiber has been domestically produced, and its cost is much lower than that of carbon fiber. It has been applied to fiber reinforced cement products, pavement geogrid, automotive friction materials and other fields. Summary of the invention

The object of the present invention is to provide a method for repairing and reinforcing and/or reinforcing a pipeline with a basalt fiber composite material, characterized in that a basalt fiber composite material is laid in a portion where the pipeline needs to be repaired and/or reinforced, and the method costs Low, safe and reliable, easy to construct. Because the volume resistivity and surface resistivity of basalt fiber are more than 10 ¹⁽⁾ Ω·πι, it has good electrical insulation properties and dielectric properties. Therefore, basalt fiber composite can be used as the insulation layer of the pipeline, and no similar electricity will occur. The risk of occasional corrosion or other electrochemical corrosion.

One of the methods of laying a basalt fiber composite in a section where the pipeline needs to be repaired and/or reinforced includes the following steps:

(1) applying a curable polymer to the surface of the pipe;

(2) laying high-strength basalt fiber and rolling it so that the curable polymer is impregnated with basalt fiber;

Repeat (1) and (2) multiple times, and then cure.

This method is completely wet-bonded. When there are irregularities such as weld defects or defects in the pipe body or pipe fittings (such as tees, elbows, reducers, flanges, small pipe joints, etc.), Good Workability. In operation, try to make the curable polymer evenly distributed and completely impregnate the basalt fiber. When laying basalt fiber, it is necessary to reduce the bubble as much as possible, P has a low void ratio, and if necessary, vacuuming measures can be taken.

A method of laying a basalt fiber composite in a section where the pipeline needs to be repaired and/or reinforced may also employ another method, including the following steps:

(1) dip-coating a curable polymer on a surface of a basalt, and forming a basalt fiber prepreg;

(2) laying basalt fiber prepreg;

Repeat (1) and (2) multiple times, and then cure.

This method is dry laying, is more suitable for on-site pipeline conditions, has no large irregularities, and non-shaped pipe fittings (such as tees, elbows, reducers, flanges, small pipe joints, etc.) At this point, the on-site operation is more time-saving, which is conducive to gaining time when repairing on site.

The basalt fiber prepreg refers to the dip coating of the curable polymer onto the basalt fiber, and forms a semi-finished product for storage through a certain process. The preparation method of the prepreg differs according to the method of impregnating the fiber by the curable polymer: solution dipping method, hot melt dipping and film rolling method, and powder method. In general, prepregs mostly require low temperature storage, and recently there are products stored at room temperature.

Since the prepreg can be prepared in advance, the content of the curable polymer can be strictly controlled, so that the quality of the prepreg can be more easily controlled. In order to improve the curing quality during curing, vacuum curing can be employed.

In practical applications, according to the specific conditions of the pipeline, the skilled person can determine the number of layers, the width and the amount of reinforcing materials of the basalt fiber composite according to the usual defect reinforcement parameters or the pipeline reinforcement design method.

In the above method, the fiber composite materials of the respective layers may be laid along the axial direction of the pipeline, laid in a circumferential direction or laid at an angle, or may be any combination of several laying methods. In practical application, the professional technician can design according to the specific conditions of the pipeline.

The fibers described in the above methods are continuous fibers selected from the group consisting of unidirectional fibers, orthogonal or oblique weftless laminates, two-dimensional fabric laminates, and multidirectional woven fibrous materials. In actual application, it can be selected according to the specific conditions of the pipeline. In general, unidirectional fibers are often used for ease of design. However, for the convenience and safety of construction, other multidirectional fibers are sometimes used. The bulk material is selected from the group consisting of a thermosetting resin, a thermoplastic resin, and a high performance resin, preferably a thermosetting resin; the auxiliary material is selected from the group consisting of a curing agent, a coupling agent, an initiator, a diluent, a crosslinking agent, a flame retardant, a polymerization inhibitor, and an antistatic agent. Agents, light stabilizers and fillers. The thermosetting resin is selected from the group consisting of epoxy resins, phenolic resin, Unsaturated polyester resin, urethane resin, polyimide resin, bismaleimide resin, silicone resin, propyl propyl resin or modified resin thereof.

Among them, epoxy resin and basalt fiber have strong bonding force, high mechanical properties, excellent dielectric properties and good chemical resistance, so epoxy resin is often used.

Before the pipeline is repaired and/or enhanced, the pipeline may be optionally surface treated, such as degreasing, descaling, phosphating, passivation, coupling, etc., if the pipeline has In the case of unevenness, it may optionally be filled with a filling resin.

In addition to basalt fiber composites, anti-corrosion materials can be used for anti-corrosion, including polyurea or polyurethane spray, polyethylene or polypropylene cold-wrap adhesive tape winding.

The parts that need to be replenished and/or enhanced include defective pipes, pipe fittings, or pipes and pipe fittings that require no reinforcement. The defects described therein include volumetric defects, planar (cracked) defects, dispersion-damaged defects (hydrogen bubbling, microcracking), geometric defects (nozzles, misaligned edges, etc.).

The method of repairing and reinforcing and/or reinforcing the pipeline with the basalt fiber composite material can be applied to the metal pipeline, the non-metal pipeline, preferably the metal pipeline, and more preferably the in-service oil and gas pipeline.

In order to ensure the construction quality, the vertical and horizontal overlap of basalt fiber 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.

In order to ensure the construction quality, when excavation and backfilling are required, it should be carried out in accordance with the specified 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 completion of the reinforcement construction, and confirm that there is no leakage point in the excavation pipe section, the sand or eucalyptus is used for stratified tamping backfilling, and the site is cleaned and restored to the original appearance 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

Figure 1 Experimental picture of the tube,

Figure 2 is a schematic diagram of the defect, the defect size is 49mmx l8mmx3.5mm,

Figure 3: The defect is made of 300mm wide basalt fiber composite reinforced pipe.

Figure 4 shows the pipe after blasting. detailed description

In order to further illustrate the method and construction process of the present invention, the following examples are given. However, these examples do not 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 φ273 steel pipe was taken as an example to simulate the possible defect size of the oil and gas pipeline, and the technology was evaluated by the hydraulic blasting test method. The test tubes and defects are shown in Figure 1.

The test process is as follows:

1) Intercepting the common pipeline pipe of the oil and gas pipeline 3m (the pipe is Q235 spiral welded pipe, the pipe diameter is

273mm, wall thickness is 7mm), and the ends are sealed with a head that has a vent hole and a water inlet hole (see Figure 1).

2) Defects in the defect size (49mmx l8mmx3.5mm).

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

4) Then fill the defect with a filling material (epoxy mortar).

5) After the surface of the material to be filled is dry, apply a phenolic resin curable polymer to the surface of the pipe, and then lay a 300 mm wide unidirectional basalt fiber along the pipe. Repeat several times and lay a total of 8 layers. As shown in Figure 3.

6) After the reinforcing layer is solidified, the test tube is filled with water and vented. When the test sample is filled with water and does not leak, the pressure is gradually increased until the sample is destroyed, as shown in Fig. 4.

The results of the blasting test show that: the damage is generated at the unrepaired pipe body, and the damage is a typical tear type failure; the test tube has obvious expansion phenomenon, and the repaired and reinforced defect is not obvious. The change; the blasting pressure of the pipe after reinforcement is 16.7Mpa, which is much higher than the design working pressure of the sample (6.4 Mpa), indicating that the technology has achieved the purpose of reinforcement.

Example 2

Similar to Example 1, the stiletto fiber composite was used to reinforce the spiral weld defect, and then the hydrostatic blasting experiment was used to verify the reinforcing effect.

The experimental process is as follows:

1) Cut the common pipe line of the oil and gas pipeline by 3.5m (the pipe is Q235 spiral welded pipe with a diameter of 325mm and a wall thickness of 7mm), and the ends are sealed with a head with a vent hole and a water inlet hole.

2) Make dimensions (length X width X depth = 60mmx l0mmx5.16mm) at the pipe spiral weld Defects.

3) Degreasing and removing the tube parts that need to be reinforced.

4) Fill the defect with anko filling resin.

5) After the surface of the material to be filled is dry, a 500mm wide basalt fiber prepreg is laid on the surface of the pipe. A total of 10 floors are laid. It is then heated to cure.

The preparation process of the basalt fiber prepreg is as follows: The epoxy 634 glue is placed in the glue tank, heated to melt, and then completely immersed in the basalt fiber, and then subjected to hot pressing to melt the resin matrix, and the fiber is embedded in the resin matrix. . Finally, it is cooled and trimmed to obtain a prepreg.

6) After the reinforcing layer is solidified, the test tube is filled with water and vented. When the test sample is filled with water and does not leak, the pressure is gradually increased until the sample is destroyed.

The results of the blasting test show that: the damage is generated at the unrepaired pipe body, and the damage is a typical tear type failure; the test tube has obvious expansion phenomenon, and the repaired and reinforced defect is not obvious. The change; the blasting pressure of the pipe after reinforcement is 18.7Mpa, which is much higher than the design working pressure of the sample (6.4 Mpa), indicating that the technology has achieved the purpose of reinforcement.

Example 3

Similar to Example 1, the basalt fiber composite was used to repair and strengthen the pipeline requiring supercharging, and then the hydrostatic blasting experiment was used to verify the reinforcing effect.

The experimental process is as follows:

1) Intercepting the common pipeline pipe of oil and gas pipeline 3.5m (the pipe is Q235 spiral welded pipe, the pipe diameter is 325mm, the wall thickness is 7mm, the design pressure is 7.3MPa, and it is to be increased to 7.8MPa), and the exhaust holes are left at both ends. The head of the inlet hole is blocked.

2) Degreasing and derusting the entire pipe body.

3) Apply epoxy-based curable polymer to the surface of the pipe, and then lay a two-way cross-woven basalt fiber along the pipe. After rolling, repeat several times and lay a total of 8 layers.

4) After the reinforcing layer is solidified, the test tube is filled with water and vented. When the test sample is filled with water and does not leak, the pressure is gradually increased until 10.8 MPa (7.8 MPa/0.72 (design coefficient)).

After the pressure is released, the pipe body shows no signs of yielding, and the circumference and deformation of the pipe body are about zero, indicating that the technology has reached the goal of increasing design pressure.

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 variations and modifications are within the scope of the invention.

Claims

Rights request

A method for repairing and reinforcing and/or reinforcing a pipeline with a basalt fiber composite material, characterized in that a basalt fiber composite material is required to be "reinforced and/or reinforced" on the surface of the pipeline.

2. The method of claim 1 wherein the reinforced reinforced and/or reinforced portion is required to be repaired on the surface of the pipe, and the laying of the basalt fiber composite material comprises the steps of:

(1) applying a curable polymer to the surface of the pipe;

(2) laying basalt fiber and rolling it so that the curable polymer is impregnated with basalt fiber;

Repeat (1) and (2) multiple times, and then cure.

3. The method of claim 1 wherein the reinforced reinforced and/or reinforced portion is required to be repaired on the surface of the pipe, and the laying of the basalt fiber composite material comprises the steps of:

(1) dip coating a curable polymer on the surface of basalt fiber to form a basalt fiber prepreg; (2) laying a basalt fiber prepreg;

Repeat (1) and (2) multiple times, and then cure.

4. The method of any of claims 2-3, wherein the layers of fibers can be laid axially along the pipe, laid circumferentially or at an angle, or can be any combination of several laying methods.

5. The method of any of claims 1-4, wherein the fibers are continuous fibers selected from the group consisting of unidirectional fibers, orthogonal or oblique weftless laminates, two-dimensional fabric lamination, multi-directional Woven fiber material.

6. The method of any of claims 2-5, wherein the curable polymer comprises a matrix material and optionally an auxiliary material; the matrix material is selected from the group consisting of thermosetting resins, thermoplastic resins, and high performance resins, preferably thermosetting resins; It is selected from the group consisting of a curing agent, a coupling agent, an initiator, a diluent, a crosslinking agent, a flame retardant, a polymerization inhibitor, an antistatic agent, a light stabilizer, and a filler.

7. The method of claim 6, wherein the thermosetting resin is selected from the group consisting of epoxy resins, phenolic resins, unsaturated polyester resins, polyurethane resins, polyimide resins, bismaleimide resins, silicones, and olefins. The propyl resin or a modified resin thereof is preferably an epoxy resin.

8. A method according to any one of claims 1 to 7, which may optionally be surface treated, such as degreasing, descaling, phosphating, passivating, prior to repairing or reinforcing the pipeline. Coupling can improve the interface bonding force.

9. The method of any of claims 1-8, wherein the pipe is uneven, optionally filled with a flattening resin.

10. The method of any of claims 1-9, further comprising preserving the outer basalt fiber composite with an outer anticorrosive material, including polyurea or polyoxyester spray, polyethylene or polypropylene cold wrap tape wrap.

11. The method of any of claims 1-3, wherein the repairing and/or reinforcing portions are required to include defective pipes, pipe fittings, or pipes and pipe fittings that require no reinforcement.

12. The method of claim 11 wherein said defects comprise volumetric defects, planar defects, diffuse damage defects, geometric defects.

13. The method of any of claims 1 - 12, wherein the conduit is selected from a metal conduit or a non-metallic conduit, preferably a metal conduit, more preferably an in-service oil and gas delivery conduit.