Method for Mitigating Stray Current Corrosion in Buried Pipelines Using Calcareous Deposits.

Area of Science:

• Materials Science
• Corrosion Engineering
• Electrochemistry

Background:

• Stray current corrosion poses a significant threat to buried pipelines, causing rapid material degradation.
• Existing mitigation methods for stray current corrosion are often inadequate.
• Calcareous deposits offer a potential solution by reducing current flow and preventing corrosion.

Purpose of the Study:

• To investigate the effectiveness of calcareous deposits (Ca, Mg, and mixed Ca-Mg) in mitigating stray current corrosion.
• To analyze the properties of these deposited layers using advanced characterization techniques.
• To evaluate the performance of different calcareous deposits as current barriers.

Main Methods:

• Formation of calcareous deposit layers (Ca, Mg, Ca-Mg) at current inflow areas.
• Characterization using Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDS), and X-ray Diffraction (XRD).
• Electrochemical testing to assess current reduction and corrosion mitigation.

Main Results:

• All tested calcareous deposits acted as effective current barriers, reducing inflow current at cathodic sites.
• The calcium carbonate (CaCO3) layer demonstrated the highest effectiveness in mitigating stray current corrosion.
• The calcium-based layer was notably thick and dense, superiorly blocking stray currents compared to magnesium-based or mixed layers.

Conclusions:

• Calcareous deposits are a viable countermeasure against stray current corrosion in buried pipelines.
• Calcium carbonate layers offer superior protection due to their structure and resistance to interference from magnesium hydroxide.
• The findings highlight the potential of engineered calcareous deposits for enhancing pipeline integrity.