Corrosion Inhibitor Performances for Carbon Dioxide Corrosion of N80 Steel Under Static and Flowing Conditions

Inhibition for carbon dioxide (CO₂) corrosion of N80 steel by quaternary alkynoxymethyl amine (IMC-80-Q) in 3% sodium chloride (NaCl) solution was investigated under static and flowing conditions using a modified rotating disk apparatus. The effects of flow velocity and concentration of inhibitor on inhibition performance were performed using a weight-loss test, scanning electron microscope (SEM) observation, and electrochemical techniques including electrochemical impedance spectroscopy (EIS), linear polarization resistance, and polarization curves. The results showed that flow velocity had strong effects on the inhibitor performances. Inhibition efficiency (η) and polarization resistance (R_p) exhibited the peak-value phenomenon at an inhibitor concentration of 150 mg/L when flow velocity was less than 5 m/s, in contrast with the 300 mg/L when flow velocity was higher than 5 m/s. Critical flow velocity in the uninhibited solution was between 4 m/s and 5 m/s.