The effect of acetic acid and acetate on CO2 corrosion of carbon steel

Abstract

PurposeThe purpose of this paper is to consider the effect of acetic acid and acetate on the anodic and cathodic reactions of carbon steel present in CO2 corrosion.Design/methodology/approachThe corrosion behaviour of carbon steel (N80) in CO2‐saturated 1% NaCl solution at 50°C and 0.1 MPa was investigated by using weight‐loss tests, electrochemical methods (polarization curves and electrochemical impedance spectroscopy) and surface analysis (scanning electron microscopy).FindingsThe results indicated that: both HAc and Ac− significantly increased the corrosion rate of carbon steel, and the surface chemical reactions of cathodic reduction were enhanced in the presence of HAc and Ac−. Because adsorbed HAc could be reduced directly in the presence of Ac−, the corrosion rate increased, even though the pH of the solution increased. Ac− played an important role in the anodic dissolution processes, which mainly affects the formation/adsorption of intermediates, and acts to form more soluble corrosion products.Originality/valueThe results of this work clarify the role of acetic acid or acetate in the anodic and cathodic reactions of CO2 corrosion.