Study of Corrosion and Inhibition of Carbon Steel in CO2 Containing Natural Gas at High Temperature

The ILI data indicated that corrosion has taken place inside the pipeline transporting the wet natural gas containing CO₂ at very high temperature. A corrosion inhibitor was injected into the pipeline to protect carbon steel from corrosion. The corrosion modeling results showed very high corrosion rate under the operating conditions. The severity of corrosion inside the pipeline detected by ILI was much lower than the corrosion prediction modeling results. The finding in this study showed the passivation film formed under the operating conditions at very high temperature provided good protection. Yet, the corrosion inhibitor deteriorated the film structure and its protection. A compatible corrosion inhibitor to the passivation film is required to protect the pipeline.