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

Purpose - The 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/approach - The corrosion behaviour of carbon steel (N80) in CO2-saturated 1% NaCl solution at 50 degrees 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). Findings - The 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/value - The results of this work clarify the role of acetic acid or acetate in the anodic and cathodic reactions Of CO2 corrosion.