Internal corrosion is a time-dependent integrity threat that occurs when contaminates are found in natural gas such as chlorides, carbon dioxide (CO2), hydrogen sulfide (H2S), and water or other contaminants. The identification, mitigation, and repair of this threat can be costly and time consuming for operators; however, if proper actions are not implemented to ensure pipeline integrity, internal corrosion may occur and potentially lead to pipeline failure. Identification of internal corrosion is typically determined through in-line inspection (ILI) technologies or internal corrosion direct assessment (ICDA), where ILI is not practical. Preventative measures such as product quality control, corrosion inhibitors, cleaning pigs, and internal coating systems can be employed to limit the impact of internal corrosion. Once internal corrosion has been identified, repair options should be considered to restore the integrity of the pipeline.

Internal corrosion in natural gas pipelines is more challenging to observe and mitigate than external corrosion due to accessibility. The intent of this document is to discuss how internal corrosion occurs, identifying locations of internal corrosion, mitigation techniques, and repair options.

Subject
Water, Pipeline integrity management, Aluminum zinc indium alloys, Magnesium alloys, Pipelines, Natural gas, Internal inspection, Repair, Internal corrosion, Steel, Internal corrosion direct assessment, Copper nickel alloys, Electrolytes
Keywords:
assessment, corrosion, electrolyte, ICDA, ILI, integrity, internal, mitigation, PHMSA, repair
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2023
Association for Materials Protection and Performance (AMPP)
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