Application advantages of carbon fiber in reinforcement and corrosion protection of submarine pipelines

The submarine pipeline is known as the lifeline of offshore oil and gas field development and the most effective and safest means of transportation for the development of offshore oil and gas resources. However, due to the harsh service environment of the pipeline, its own possible defects, coupled with the long-term uninterrupted service process, and the existence of many uncertain factors, the corrosion, defects and damage of the pipeline are inevitable. The existence of these defects seriously threatens the safe operation of the pipeline If it is not handled and repaired in time, it may cause major losses and accidents.

At present, the repair and reinforcement of pipelines generally adopt repair methods such as replacement of pipelines, welding, fixtures and composite materials. Carbon fiber composite material reinforcement technology is a type of composite material repair technology. Carbon fiber is coated with a bonding resin to form a reinforcement layer outside the pipe to share the load of the pipe and reduce the stress and strain of the pipe wall, thereby restoring or improving the pipe’s performance. Pressure bearing capacity is currently the most promising repair and reinforcement technology.

Carbon fiber composite sheet repairing steel pipeline structure is a structural repair and reinforcement technology developed in the 1990s. This technology is highly valued internationally and has been widely used in special structures such as chemical plants, civil buildings, and bridges. Become the development trend of steel pipeline structure repair and reinforcement. Compared with traditional metal material repair methods, this repair technology has five obvious advantages. One is that the tensile strength and strength modulus are high, and the creep resistance is excellent; the other is that it can be designed and can be designed according to the requirements of use and acceptance. The material is laid on the design of the material under the condition of the force; the third is that it has a variety of molding processes, which can repair and strengthen the large area or the more complex structure of the pipe and the irregular pipe fittings such as bends, tees, and small heads; fourth, the construction is simple and fast, and the repair The strong repair time is short and the cost is low; the fifth is the advantages of no welding, no fire, repair under pressure, and low risk.

In the past 10 years, carbon fiber composite repair technology has been more and more used in the repair of defective pipelines such as severe corrosion, mechanical damage, cracks and leaks, and domestic scholars have carried out a lot of research. The carbon fiber composite material reinforcement repair system consists of four parts: carbon fiber cloth, adhesive dipping, primer and special repair agent. They work together on the pipeline as a whole. When the carbon fiber composite repair system is used for defect repair, the filling resin is first used to fill the defect, and then the carbon fiber composite material composed of carbon fiber and epoxy binder is wound on the outside of the pipe to form a composite repair on the outside of the pipe Floor. The filling resin has excellent compressive strength after curing. The carbon fiber composite material has extremely high tensile strength and elastic modulus after curing. It will limit the radial expansion and deformation of the defect by filling the resin, reduce the tensile stress and strain at the defect, and limit the stress concentration at the defect of the pipeline, so as to achieve the reinforcement and repair of the pipeline and restore the normal pressure-bearing capacity of the pipeline , Reduce the risk of the pipeline.

The carbon fiber composite repair system uses its special repairing agent to fill in the defects, and the special repairing agent has an excellent compressive strength greater than 100MPa after curing. The special repair agent and epoxy primer play a role in transmitting the pressure of the pipe wall along the radial direction. The carbon fiber and epoxy resin are wound around the pipe, and the resin is cured to produce a carbon fiber composite material. After curing, the carbon fiber composite material has a higher tensile strength. It can transmit pressure through the special repair agent and the bonding force between itself and the pipe, and share the pipe The internal pressure limits the expansion and deformation of the pipeline, reduces the tensile stress and strain at the defect, and realizes the reinforcement and repair of the pipeline defect.

Carbon fiber composite material reinforcement repair technology is a safe and reliable pipeline reinforcement repair technology that can repair and reinforce common defects such as pipeline corrosion and mechanical damage. With the continuous deepening of research on carbon fiber composite materials, the application fields of carbon fiber composite materials will continue to expand.