FBE Mending Technology in the Process Pipeline of Offshore Oil Platform

introduction

Fusion bond epoxy powder coating (Fusion bond epoxy coating, referred to as FBE) is a thermosetting heavy-duty anti-corrosion epoxy powder coating that uses air as a carrier to transport and disperse.

At present, FBE has been widely used in many professional fields such as water supply, ventilation, chemical industry, petroleum drill pipe, etc.

However, due to the inherent characteristics of FBE, the design, construction, and inspection of FBE require high standards to ensure that the coating is not easy to fail

All of the above are common FBE design and construction issues

1 Anti-corrosion FBE in the process pipeline of offshore oil platform

As a form of anti-corrosion solution in the process pipelines of offshore oil platforms, FBE is used more and more

2 Analysis of common mouth-filling methods for internal FBE

In view of the characteristics of the offshore oil platform process pipeline and the difficulty of coating construction, the on-site patching of the internal coating FBE is a key link related to the overall internal coating quality

2.

Welding connection is the most common connection method, which is simple and easy to operate

On the other hand, the offshore oil platform process pipeline has a small pipe diameter, and the pipeline direction is changeable and has a certain angle, even vertical
.
Therefore, if the welding connection method is adopted, the on-site welding joints should be reduced as much as possible, and the welding joints should be arranged in a position that is easy to construct
.
This will inevitably impose stricter requirements on pipeline distribution design, segmented design, prefabrication capacity, assembly capacity, and the construction capacity of the internal coating FBE constructor
.
At the same time, due to the limitations of the welding method, it is difficult to inspect and repair the internal FBE of the pipeline after the project is put into production, which will also increase the maintenance risk
.

Figure 1 Schematic diagram of welding connection method

2.
2 Flange connection

Flange connection is a common method of mechanical connection (see Figure 2)
.
The use of flange connection can effectively avoid the damage of the internal coating caused by welding, ensure the continuity of the internal anti-corrosion coating, and the construction efficiency is high
.
In the pipeline prefabrication stage, the flanges are welded and installed in advance.
After the internal coating construction is completed, only the flange butt installation is carried out in the on-site assembly stage
.
This installation method is simple, easy to standardize and arrange construction
.
However, compared with other connection methods, flange connection will greatly increase the quality of offshore oil platforms, which has a great impact on the quality control of floating platforms
.
Subject to the limitations of the flange connection, it will also increase the leakage risk of the internally coated FBE oil and gas pipeline system
.
At the same time, the cost of flanges is relatively high, which will affect the overall cost of the project
.

Figure 2 Schematic diagram of flange connection mode

2.
3 Connection method of inner lining jacket method

The pipeline using the liner jacket method link method is shown in Figure 3
.
Need to expand at both ends of the pipeline, that is, expand the pipe diameter (expansion treatment is also not necessary, but the internal diameter of the pipeline may be reduced)
.
After the pipeline is prefabricated, the inner surface of the pipeline is painted with FBE
.
When the pipeline is assembled, the liner jackets are installed in the expansion ports of the pipeline ends at the two ends of the mating joint respectively
.
After the installation of the lining jacket is completed, the pipeline is welded to the joint
.
The material of the inner lining jacket can be non-metallic or metallic, such as glass fiber reinforced plastic or the same material as the pipeline
.

The lining and jacketing method is exquisite in design, high in strength, excellent in corrosion resistance, easy to install, and tightly matched with the pipe body, theoretically reducing the risk of leakage and reducing the quality of offshore oil platforms
.
However, it is rarely used in the complex structure of offshore oil platform process pipelines.
The reason is that the tolerance requirements and size control of pipelines and pipe fittings are very strict, and it is difficult to FBE inside the pipeline after the pipeline assembly is welded and the project is put into production.
Inspection and maintenance
.

Figure 3 Schematic diagram of the connection method of the inner lining jacket method

2.
4 Corrosion-resistant alloy joint connection method

For pipelines using corrosion-resistant alloy joints, first weld corrosion-resistant alloy rings at both ends of the pipeline, and then apply FBE inside the pipeline.
The coating needs to be overlapped on the corrosion-resistant alloy ring, as shown in Figure 4
.
When the pipeline assembly is connected, the corresponding corrosion-resistant alloy electrode can be used for welding
.
This method avoids the patching construction of the on-site coating, and can effectively solve the corrosion problem of the on-site FBE coated with FBE
.
However, the cost of corrosion-resistant alloys is higher than that of carbon steel, so it is necessary to consider the pipeline layout in advance in the project design stage to reduce the number of joints as much as possible
.

In some projects, in order to reduce the cost of this part, the method of overlaying nickel-based alloys with carbon steel joints instead of the method of using corrosion-resistant alloys as a whole is used
.
Steel grit should not be used for the surface treatment of the lap position of the corrosion-resistant alloy joint and FBE, but garnet can be used
.
However, the roughness after surface treatment with garnet is difficult to meet the standard requirements or can only be guaranteed to meet the lower limit of the standard requirements, and sand inclusion is easy to occur, which cannot be completely removed or avoided
.
These will also affect the quality of the FBE in the overlapping area
.
Compared with carbon steel, the field welding of corrosion-resistant alloy also puts forward higher requirements on welding quality
.

Figure 4 Schematic diagram of the connection method of the inner lining jacket method

Concluding remarks

The anti-corrosion of the offshore oil platform process pipeline is very important.
Compared with the reliable external anti-corrosion technology, the internal anti-corrosion is a very weak link, especially the quality of the internal anti-corrosion patch at the site port is the smooth operation of the entire offshore oil platform process system Key link
.
The several methods for welding epoxy powder internal joints in the process pipelines of offshore oil platforms introduced in this article are only common ones, each of which has its own advantages and disadvantages, and all have certain limitations
.
Therefore, it is very important to develop a technology that can completely solve the internal repair, especially suitable for the internal repair of the process pipeline of the offshore oil platform.
This requires scientific researchers to increase the research on the internal anti-corrosion repair technology and integrate it as soon as possible.
The new results are put into use
.