Localised Corrosion on Carbon Steel in Sour Glycolic Solutions

Some results from a large JIP on sour corrosion in sour wet gas pipelines with hydrate preventers (glycols) are presented and discussed. Experiments were run in flow loops and glass cell equipment with 0.1-5 bar CO₂, 0.1-5 bar H₂S and temperatures in the range of 15-90^oC. Salinity and pH were also adjusted to simulated different operating conditions. It was found that alkaline chemical treatment for corrosion control (pH stabilisation) was inefficient against localised sour corrosion above 0.1 bar H₂S, and in some cases even promoted localised attacks.