The corrosion inhibition of 2-mercaptobenzimidazole on A106 carbon steel and its stability in a post-combustion CO2 capture system with application of 5 M monoethanolamine aqueous solutions has been evaluated by linear polarization resistance, electrochemical impedance spectroscopy, immersion corrosion testing, scanning electron microscopy/energy dispersive spectroscopy, x-ray diffraction, and liquid chromatography-mass spectroscopy. Although no notable layer of protective corrosion product was found on the A106 surface at 80°C and atmospheric pressure for >180 h, corrosion was inhibited, and its polarization resistance increased nearly an order of magnitude when 2-mercaptobenzimidazole was added. However, degradation of 2-mercaptobenzimidazole, associated with the formation of an FeS layer with cracks, occurred at 108°C and 4.13×105 Pa.

Subject
Scanning electron microscopy, X-ray diffraction, Test methods, Iron sulfides, Electrochemical testing, Solid solutions, Corrosion inhibitors, Surface layers, Carbon dioxide, Carbon steel, Carbon, Ferrite, Linear polarization resistance
Keywords:
aqueous environments, autoclave testing, carbon dioxide, carbon steel, galvanic corrosion, organic inhibitor, sulfide stress cracking
© 2015 NACE International
2015
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