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FBE Coated Line Pipe

Choosing the Right Coatings: 3LPE Coating vs FBE Coating

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Introduction

In the oil, gas, and water transmission industries, pipeline coatings play a crucial role in ensuring the long-term performance and protection of buried or submerged pipelines. Among the most widely used protective coatings are 3LPE (Three-Layer Polyethylene Coating) and FBE (Fusion Bonded Epoxy Coating). Both provide corrosion resistance and mechanical protection, but they offer distinct advantages depending on the application environment. Understanding their differences is essential for making an informed decision in pipeline coating selection. 3LPE coating vs FBE coating, let’s explore in-depth.

1. Overview of 3LPE Coating vs FBE Coating

3LPE Coating (Three-Layer Polyethylene Coating)

3LPE is a multi-layered protective system that combines different materials to create an effective shield against corrosion and physical damage. It consists of three layers:

  • Layer 1: Fusion Bonded Epoxy (FBE): This provides strong adhesion to the pipe surface and offers excellent corrosion resistance.
  • Layer 2: Copolymer Adhesive: The adhesive layer bonds the epoxy layer to the outer polyethylene layer, ensuring a strong bond.
  • Layer 3: Polyethylene (PE): The final layer offers mechanical protection from impacts, abrasions, and environmental conditions.

FBE Coating (Fusion Bonded Epoxy Coating)

FBE is a single-layer coating made from epoxy resins that are applied in a powder form. When heated, the powder melts and forms a continuous, highly adherent layer around the pipe surface. FBE coatings are primarily used for corrosion resistance in environments that may expose the pipeline to water, chemicals, or oxygen.

2. 3LPE Coating vs FBE Coating: Understanding the Differences

Feature 3LPE Coating FBE Coating
Structure Multi-layer (FBE + adhesive + PE) Single-layer epoxy coating
Corrosion Resistance Excellent, due to the combined barrier of FBE and PE layers Very good, provided by epoxy layer
Mechanical Protection High impact resistance, abrasion resistance, and durability Moderate; susceptible to mechanical damage
Operating Temperature Range -40°C to +80°C -40°C to +100°C
Application Environment Suitable for harsh environments, including offshore and buried pipelines Ideal for buried or submerged pipelines in less harsh environments
Application Thickness Typically thicker, due to multiple layers Typically thinner, single-layer application
Cost Higher initial cost due to multi-layer system More economical; single-layer application
Longevity Provides long-term protection in aggressive environments Good for moderate to less aggressive environments

3. Advantages of 3LPE Coating

3.1. Superior Corrosion and Mechanical Protection

The 3LPE system offers a robust combination of corrosion protection and mechanical durability. The FBE layer provides excellent adhesion to the pipe surface, acting as the primary barrier against corrosion, while the PE layer adds additional protection from mechanical stresses, such as impacts during installation and transportation.

3.2. Ideal for Buried and Offshore Pipelines

3LPE coatings are particularly well-suited for pipelines that will be buried underground or used in offshore environments. The outer polyethylene layer is highly resistant to abrasions, chemicals, and moisture, making it ideal for long-term performance in harsh conditions.

3.3. Extended Lifespan in Aggressive Environments

Pipelines coated with 3LPE are known for their longevity in aggressive environments such as coastal areas, high-salt regions, and locations prone to soil movement. The multi-layered protection ensures resistance to moisture penetration, soil contaminants, and mechanical damage, reducing the need for frequent maintenance.

4. Advantages of FBE Coating

4.1. Excellent Corrosion Resistance

Despite being a single-layer coating, FBE provides excellent resistance to corrosion, particularly in less harsh environments. The fusion-bonded epoxy layer is highly effective at preventing moisture and oxygen from reaching the steel pipe surface.

4.2. Heat Resistance

FBE coatings have a higher operating temperature limit compared to 3LPE, making them suitable for pipelines exposed to higher temperatures, such as in certain oil and gas transmission lines. They can operate in temperatures up to 100°C, compared to 3LPE’s typical upper limit of 80°C.

4.3. Lower Application Costs

Since FBE is a single-layer coating, the application process is less complex and requires fewer materials than 3LPE. This makes FBE a cost-effective solution for pipelines in less aggressive environments, where high-impact resistance is not critical.

5. 3LPE Coating vs FBE Coating: Which One Should You Choose?

5.1. Choose 3LPE When:

  • The pipeline is buried in harsh environments, including coastal regions or areas with high soil moisture content.
  • High mechanical protection is needed during handling and installation.
  • Long-term durability and resistance to environmental factors like water and chemicals are required.
  • The pipeline is exposed to aggressive environments where maximum corrosion protection is essential.

5.2. Choose FBE When:

  • The pipeline will be operating at higher temperatures (up to 100°C).
  • The pipeline is not exposed to severe mechanical stresses, and corrosion protection is the primary concern.
  • The application requires a more economical solution without compromising corrosion resistance.
  • The pipeline is located in less aggressive environments, such as low-salt soils or moderate climate areas.

6. 3LPE Coating vs FBE Coating: Challenges and Limitations

6.1. Challenges with 3LPE

  • Higher Initial Costs: The multi-layer system involves more materials and a more complex application process, resulting in higher initial costs.
  • Thicker Coating: While this adds durability, the thicker coating may require more space in certain applications, especially in tightly confined pipeline installations.

6.2. Challenges with FBE

  • Lower Mechanical Strength: FBE coatings lack the robust mechanical protection provided by 3LPE, making them more susceptible to damage during handling and installation.
  • Moisture Absorption: Although FBE provides good corrosion resistance, its single-layer design makes it more prone to moisture ingress over time, particularly in aggressive environments.

7. Conclusion: Making the Right Choice

Choosing between 3LPE and FBE coatings depends on the specific conditions and requirements of the pipeline. 3LPE is ideal for harsh environments where long-term durability and mechanical protection are priorities, while FBE offers a cost-effective solution for environments where corrosion resistance is the main concern and mechanical stresses are moderate.

By understanding the strengths and limitations of each coating, pipeline engineers can make informed decisions to maximize the longevity, safety, and performance of their transmission systems, whether transporting oil, gas, or water.

What is fusion bond epoxy /FBE coating for steel pipes?

Fusion Bonded Epoxy (FBE) Coated Line Pipe

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Anti-corrosive steel pipe refers to a steel pipe that is processed by anti-corrosive technology and can effectively prevent or slow down the corrosion phenomenon caused by chemical or electrochemical reactions in the process of transportation and use.
Anti-corrosion steel pipe is mainly used in domestic petroleum, chemical, natural gas, heat, sewage treatment, water sources, bridges, steel structures, and other pipeline engineering fields. Commonly used anti-corrosion coatings include 3PE coating, 3PP coating, FBE coating, polyurethane foam insulation coating, liquid epoxy coating, epoxy coal tar coating, etc.

What is fusion bonded epoxy (FBE) powder anti-corrosive coating?

Fusion-bonded epoxy (FBE) powder is a kind of solid material that is transported and dispersed by air as a carrier and applied on the surface of preheated steel products. Melting, leveling and curing form a uniform anti-corrosion coating, which is formed under high temperatures. The coating has the advantages of easy operation, no pollution, good impact, bending resistance, and high-temperature resistance. Epoxy powder is a thermosetting, non-toxic coating, which forms a high molecular weight cross-linked structure coating after curing. It has excellent chemical anti-corrosion properties and high mechanical properties, especially the best wear resistance and adhesion. It is a high-quality anti-corrosion coating for underground steel pipelines.

Classification of fused epoxy powder coatings:

1) according to the use method, it can be divided into: FBE coating inside the pipe, FBE coating outside the pipe, and FBE coating inside and outside the pipe. The outer FBE coating is divided into single-layer FBE coating and double-layer FBE coating(DPS coating).
2)According to the usage, it can be divided into: FBE coating for oil and natural gas pipelines, FBE coating for drinking water pipelines, FBE coating for fire fighting pipelines, coating for anti-static ventilation pipelines in coal mines, FBE coating for chemical pipelines, FBE coating for oil drill pipes, FBE coating for pipe fittings, etc.
3) according to curing conditions, it can be divided into two types: fast curing and ordinary curing. The curing condition of fast curing powder is generally 230℃/0.5~2min, which is mainly used for external spraying or three-layer anti-corrosion structure. Due to the short curing time and high production efficiency, it is suitable for assembly line operation. The curing condition of ordinary curing powder is generally more than 230℃/5min. Due to the long curing time and the good leveling of the coating, it is suitable for in-pipe spraying.

Thickness of FBE coating

300-500um

Thickness of DPS(double layer FBE) coating

450-1000um

standard of coating

SY/T0315,CAN/CSA Z245.20,

AWWA C213,Q/CNPC38,etc

Use

Land and underwater pipeline anticorrosion

Advantages

Excellent adhesive strength

High insulation resistance

Anti-aging

Anti-cathode stripping

Anti high temperature

Resistance to bacteria

Small cathode protection current (only1-5uA/m2)

 

Appearance

 Performance index Test method
Thermal characteristics Surface smooth, color uniform, no bubbles, cracks and holidays                                                       Visual inspection

24h or 48h cathodic disbondment (mm)

 ≤6.5

SY/T0315-2005

Thermal characteristics(rating of)

1-4

Cross-section porosity (rating of)

 1-4
3 degree centigrade flexibility(Order specified minimum temperature+3 degree centigrade

No track

1.5J impact resistance(-30 degree centigrade)

 No holiday
24h Adhesion(rating of)

1-3

Breakdown voltage(MV/m)

 ≥30
Mass resistivity(Ωm)

≥1*1013

Anti-corrosion method of fusion bonded epoxy powder:

The main methods are electrostatic spraying, thermal spraying, suction, fluidized bed, rolling coating, etc. Generally, friction electrostatic spraying method, suction method, or thermal spraying method are used for coating in the pipeline. These several coating methods have a common characteristic, that is needed before spraying the workpiece preheated to a certain temperature, melt powder a contact namely, heat should be able to make the film continue to flow, further flow flat covers the whole surface of the steel tube, especially in the cavity on the surface of the steel tube, and on both sides of weld molten coating into the bridge, combined closely with the coating and the steel tube, minimize pores, and curing within the prescribed time, the last water cooling solidification process termination.