The effect of acetic acid on the pit propagation in CO₂ corrosion of carbon steel

J. Amri (1, 2) , E. Gulbrandsen (3) , Ricardo P. Nogueira (1, 2)

1 SIMaP - Science et Ingénierie des Matériaux et Procédés
2 LEPMI - Laboratoire d'Electrochimie et de Physico-chimie des Matériaux et des Interfaces
3 IFE - Institute for Energy Technology

The role of acetic acid (HAc) on the pit growth in CO₂ corrosion of carbon steel pipelines is studied by means of an artificial pit electrode. The current flowing between the artificial pit and the outer surface was measured with a zero resistance ammeter. It is shown that the corrosion potential increases with increasing HAc concentration. Depletion of HAc inside the pit imposed a potential difference that triggered the pit growth. The pit did not grow in absence of HAc. The pit growth was self-sustained only to a certain pit depth, beyond which the dissolution current at the bottom of the pit vanished. This is in good agreement with field observations mainly in the case of top-of-line corrosion phenomena.

Mots clés: CO₂ corrosion; Carbon steel; Top-of-line corrosion; Acetic acid; ZRA

Domaines: Matériaux; Génie des procédés

J. Amri, E. Gulbrandsen, Ricardo P. Nogueira. The effect of acetic acid on the pit propagation in CO₂ corrosion of carbon steel. Electrochemistry Communications, 2008, 10 (2), pp.200-203. ⟨10.1016/j.elecom.2007.11.028⟩. ⟨hal-00365555⟩