The anti-corrosion treatment of steel pipes for offshore and onshore applications differs due to the different environmental conditions and operational requirements they face. Here are the key differences in anti-corrosion treatment between offshore and onshore steel pipes:

Offshore Steel Pipes

1. Marine Environment: Offshore steel pipes are exposed to harsh marine environments with high salinity levels, wave action, and corrosive elements such as saltwater and marine organisms.

2. Cathodic Protection: Offshore pipelines often use cathodic protection systems, such as sacrificial anodes or impressed current systems, to protect against corrosion in seawater.

3. Coating Systems: Offshore steel pipes typically require more robust coating systems such as fusion-bonded epoxy (FBE), three-layer polyethylene (3LPE), or concrete weight coating to withstand the corrosive effects of seawater and marine conditions.

4. Abrasion Resistance: Offshore pipelines may need additional protection against abrasion from seabed movement, vessel anchoring, or other activities in the marine environment.

5. Maintenance Challenges: Accessing and maintaining corrosion protection systems on offshore pipelines can be more challenging and may require specialized equipment and personnel.

Onshore Steel Pipes

1. Soil Conditions: Onshore pipelines are often exposed to different soil conditions that can vary in terms of pH levels, moisture content, and chemical composition, leading to different corrosion mechanisms compared to offshore environments.

2. External Coatings: Onshore steel pipes commonly use coatings such as asphalt enamel, coal tar enamel, or liquid epoxy coatings to protect against soil corrosion.

3. Soil-to-Coating Interface: Onshore pipelines may require specific protection at the soil-to-coating interface to prevent underfilm corrosion caused by soil bacteria and moisture.

4. Localized Corrosion: Onshore pipelines may face localized corrosion issues in areas with high moisture content, acidic soils, or industrial pollution, requiring targeted corrosion protection measures.

5. Impact Resistance: Onshore pipelines may need additional protection against mechanical damage from construction activities, vehicular traffic, or other sources of impact.

6. Maintenance Accessibility: Maintenance and inspection of corrosion protection systems on onshore pipelines are typically more accessible compared to offshore pipelines, facilitating easier upkeep and monitoring.

Common Considerations

1. Temperature Variations: Both offshore and onshore pipelines may require protection against temperature variations that can impact the performance of corrosion protection systems.

2. UV Exposure: UV radiation can degrade coatings on both offshore and onshore pipelines exposed to sunlight, necessitating UV-resistant coating systems.

3. Regulatory Compliance: Both types of pipelines must adhere to industry standards and regulations for corrosion protection to ensure safety and environmental compliance.

In summary, the anti-corrosion treatment of offshore steel pipes focuses on protection against marine conditions and cathodic protection, while onshore steel pipes require protection against soil corrosion and may face different localized corrosion challenges based on soil composition and external factors. The choice of anti-corrosion treatment for each type of pipeline is tailored to the specific environmental conditions and operational requirements to ensure long-term integrity and performance.