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3LPE Coating vs 3LPP Coating

3LPE vs 3LPP: Comprehensive Comparison of Pipeline Coatings

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Pipeline coatings are critical in protecting steel pipelines from corrosion and other environmental factors. Among the most commonly used coatings are 3-Layer Polyethylene (3LPE) and 3-Layer Polypropylene (3LPP) coatings. Both coatings offer robust protection, but they differ in terms of application, composition, and performance. This blog will provide a detailed comparison between 3LPE and 3LPP coatings, focusing on five key areas: coating selection, coating composition, coating performance, construction requirements, and construction process.

1. Coating Selection

3LPE Coating:

  • Usage: 3LPE is widely used in the oil and gas industry for onshore and offshore pipelines. It is particularly suitable for environments where moderate temperature resistance and excellent mechanical protection are required.
  • Temperature Range: The 3LPE coating is typically used for pipelines operating at temperatures ranging from -40°C to 80°C.
  • Cost Consideration: 3LPE is generally more cost-effective than 3LPP, making it a popular choice for projects with budget constraints where the temperature requirements are within the range it supports.

3LPP Coating:

  • Usage: 3LPP is favored in high-temperature environments, such as deepwater offshore pipelines and pipelines transporting hot fluids. It is also used in areas where superior mechanical protection is needed.
  • Temperature Range: 3LPP coatings can withstand higher temperatures, typically between -20°C to 140°C, making them suitable for more demanding applications.
  • Cost Consideration: 3LPP coatings are more expensive due to their superior temperature resistance and mechanical properties, but they are necessary for pipelines that operate in extreme conditions.

Selection Summary: The choice between 3LPE and 3LPP primarily depends on the operating temperature of the pipeline, the environmental conditions, and budget considerations. 3LPE is ideal for moderate temperatures and cost-sensitive projects, while 3LPP is preferred for high-temperature environments and where enhanced mechanical protection is essential.

2. Coating Composition

3LPE Coating Composition:

  • Layer 1: Fusion Bonded Epoxy (FBE): The innermost layer provides excellent adhesion to the steel substrate and acts as the primary corrosion protection layer.
  • Layer 2: Copolymer Adhesive: This layer bonds the FBE layer to the polyethylene topcoat, ensuring strong adhesion and additional corrosion protection.
  • Layer 3: Polyethylene (PE): The outer layer of polyethylene provides mechanical protection against physical damage during handling, transportation, and installation.

3LPP Coating Composition:

  • Layer 1: Fusion Bonded Epoxy (FBE): Similar to 3LPE, the FBE layer in 3LPP serves as the primary corrosion protection and bonding layer.
  • Layer 2: Copolymer Adhesive: This adhesive layer bonds the FBE to the polypropylene topcoat, ensuring strong adhesion.
  • Layer 3: Polypropylene (PP): The outer layer of polypropylene offers superior mechanical protection and higher temperature resistance compared to polyethylene.

Composition Summary: Both coatings share a similar structure, with an FBE layer, a copolymer adhesive, and an outer protective layer. However, the outer layer material differs—polyethylene in 3LPE and polypropylene in 3LPP—leading to differences in performance characteristics.

3. Coating Performance

3LPE Coating Performance:

  • Temperature Resistance: 3LPE performs well in moderate temperature environments but may not be suitable for temperatures exceeding 80°C.
  • Mechanical Protection: The polyethylene outer layer provides excellent resistance to physical damage, making it suitable for onshore and offshore pipelines.
  • Corrosion Resistance: The combination of FBE and PE layers offers robust protection against corrosion, especially in humid or wet environments.
  • Chemical Resistance: 3LPE offers good resistance to chemicals but is less effective in environments with aggressive chemical exposure compared to 3LPP.

3LPP Coating Performance:

  • Temperature Resistance: 3LPP is designed to withstand higher temperatures, up to 140°C, making it ideal for pipelines transporting hot fluids or located in high-temperature environments.
  • Mechanical Protection: The polypropylene layer provides superior mechanical protection, especially in deepwater offshore pipelines where external pressures and physical stress are higher.
  • Corrosion Resistance: 3LPP offers excellent corrosion protection, similar to 3LPE, but with better performance in higher temperature environments.
  • Chemical Resistance: 3LPP has superior chemical resistance, making it more suitable for environments with aggressive chemicals or hydrocarbons.

Performance Summary: 3LPP outperforms 3LPE in high-temperature environments and provides better mechanical and chemical resistance. However, 3LPE is still highly effective for moderate temperatures and less aggressive environments.

4. Construction Requirements

3LPE Construction Requirements:

  • Surface Preparation: Proper surface preparation is crucial for the effectiveness of the 3LPE coating. The steel surface must be cleaned and roughened to achieve the necessary adhesion for the FBE layer.
  • Application Conditions: The application of the 3LPE coating must be carried out in a controlled environment to ensure the proper adhesion of each layer.
  • Thickness Specifications: The thickness of each layer is critical, with the total thickness typically ranging from 1.8 mm to 3.0 mm, depending on the pipeline’s intended use.

3LPP Construction Requirements:

  • Surface Preparation: Like 3LPE, surface preparation is key. The steel must be cleaned to remove any contaminants and roughened to ensure proper adhesion of the FBE layer.
  • Application Conditions: The application process for 3LPP is similar to that of 3LPE but often requires more precise control due to the higher temperature resistance of the coating.
  • Thickness Specifications: 3LPP coatings are typically thicker than 3LPE, with the total thickness ranging from 2.0 mm to 4.0 mm, depending on the specific application.

Construction Requirements Summary: Both 3LPE and 3LPP require meticulous surface preparation and controlled application environments. However, 3LPP coatings generally require thicker applications to achieve their enhanced protective qualities.

5. Construction Process

3LPE Construction Process:

  1. Surface Cleaning: The steel pipe is cleaned using methods like abrasive blasting to remove rust, scale, and other contaminants.
  2. FBE Application: The cleaned pipe is preheated, and the FBE layer is applied electrostatically, providing a strong bond to the steel.
  3. Adhesive Layer Application: A copolymer adhesive is applied over the FBE layer, bonding the FBE to the outer polyethylene layer.
  4. PE Layer Application: The polyethylene layer is extruded onto the pipe, providing mechanical protection and additional corrosion resistance.
  5. Cooling and Inspection: The coated pipe is cooled, inspected for defects, and prepared for transportation.

3LPP Construction Process:

  1. Surface Cleaning: Similar to 3LPE, the steel pipe is thoroughly cleaned to ensure proper adhesion of the coating layers.
  2. FBE Application: The FBE layer is applied to the preheated pipe, serving as the primary corrosion protection layer.
  3. Adhesive Layer Application: A copolymer adhesive is applied over the FBE layer, ensuring a strong bond with the polypropylene topcoat.
  4. PP Layer Application: The polypropylene layer is applied through extrusion, providing superior mechanical and temperature resistance.
  5. Cooling and Inspection: The pipe is cooled, inspected for defects, and prepared for deployment.

Construction Process Summary: The construction processes for 3LPE and 3LPP are similar, with differences primarily in the materials used for the outer protective layer. Both processes require careful control of temperature, cleanliness, and layer thickness to ensure optimal performance.

Conclusion

Choosing between 3LPE and 3LPP coatings depends on several factors, including the operating temperature, environmental conditions, mechanical stress, and budget.

  • 3LPE is ideal for pipelines operating at moderate temperatures and where cost is a significant consideration. It provides excellent corrosion resistance and mechanical protection for most onshore and offshore applications.
  • 3LPP, on the other hand, is the preferred choice for high-temperature environments and applications requiring superior mechanical protection. Its higher cost is justified by its enhanced performance in demanding conditions.

Understanding the specific requirements of your pipeline project is essential in selecting the appropriate coating. Both 3LPE and 3LPP have their strengths and applications, and the right choice will ensure long-term protection and durability for your pipeline infrastructure.

Introduction of 3LPE Coated Line Pipe

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Brief introduction:

The base material of 3PE anti-corrosive coating steel pipe includes seamless steel pipe, spiral welded steel pipe and straight seam welded steel pipe. Three-layer polyethylene (3PE) anti-corrosive coating has been widely used in the oil pipeline industry for its good corrosion resistance, water vapor permeability resistance and mechanical properties. 3PE anti-corrosion coating is very important for the service life of buried pipelines. Some pipelines of the same material are buried in the ground for decades without corrosion, and some are leaked in a few years. The reason is that they use different coatings.

Anti-corrosion structure:

3PE anti-corrosion coating is generally composed of three layers of structure: the first layer is epoxy powder (FBE) > 100um, the second layer is adhesive (AD) 170 ~ 250um, the third layer is polyethylene (PE) 1.8-3.7mm. In the actual operation, the three materials are mixed and integrated, which are processed to be firmly combined with the steel pipe to form an excellent anti-corrosive coating. The processing method is generally divided into two types: winding type and circular mold covering type.

3PE anti-corrosive steel pipe coating (three-layer polyethylene anti-corrosive coating) is a new anti-corrosive steel pipe coating produced by an ingenious combination of 2PE anti-corrosive coating in Europe and FBE coating widely used in North America. It has been recognized and used for more than ten years in the world.

The first layer of 3PE anti-corrosive steel pipe is epoxy powder anti-corrosive coating, and the middle layer is copolymerized adhesive with a branch structure functional group. The surface layer is high-density polyethylene anti-corrosive coating.

3LPE anti-corrosive coating combines the high impermeability and mechanical properties of epoxy resin and polyethylene. Up to now, it has been recognized as the best anti-corrosive coating with the best effect and performance in the world, which has been applied in many projects.

Advantages:

The common steel pipe will be severely corroded in the bad use environment, which will reduce the service life of the steel pipe. The service life of the anti-corrosion and heat preservation steel pipe is also relatively long. Generally, it can be used for about 30-50 years, and the correct installation and use can also reduce the maintenance cost of the pipe network. The anti-corrosion and heat preservation steel pipe can also be equipped with an alarm system, Automatic detection of pipe network leakage fault, accurate knowledge of fault location, and also automatic alarm.

3PE anti-corrosion and heat preservation steel pipes have good heat preservation performance, and the heat loss is only 25% of that of traditional pipes. Long-term operation can save a lot of resources, significantly reduce energy costs, and still have strong water-proof and corrosion-resistant ability. Moreover, it can be directly buried underground or in the water without an additional pipe trench, which is also simple, rapid, and comprehensive in construction. The cost is also relatively low, and it has good corrosion resistance and impact resistance under low-temperature conditions, and it can also be directly buried in frozen soil.

Application:

For 3PE anti-corrosion steel pipe, many people only know one thing and don’t know the other. Its function is really wide coverage. It is suitable for underground water supply and drainage, underground shotcreting, positive and negative pressure ventilation, gas drainage, fire sprinklers and other pipe networks. Waste residue and return water transmission pipeline for process water of thermal power plant. It has excellent applicability for the water supply pipeline of anti-spray and sprinkler systems. Power, communication, highway and other cable protection sleeve. It is suitable for high-rise building water supply, heat supply networks, waterworks, gas transmission, buried water transmission and other pipelines. Petroleum pipeline, chemical and pharmaceutical industry, printing and dyeing industry, etc. Sewage treatment discharge pipe, sewage pipe and biological pool anti-corrosion engineering. It can be said that 3PE anti-corrosion steel pipe is indispensable in the current construction of agricultural irrigation pipes, deep well pipes, drainage pipes and other network applications, and it is believed that through the extension of science and technology, it will still have more brilliant achievements in the future.

If you need any kind of anti-corrosion coating steel pipes such as 3PE coating steel pipes, FBE coating steel pipes and 3PP coating steel pipes, etc. Please contact us!