Electrochemical Study and Modeling of H2S Corrosion of Mild Steel

By Yougui Zheng, B. Brown, S. Nesic. Corrosion, 2013

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The internal corrosion of mild steel in the presence of hydrogen sulfide (H2S) represents a significant challenge in oil production and natural gas treatment facilities, but the true mechanisms involved in H2S corrosion are still not fully understood. The lack of knowledge makes the prediction, prevention and/or control of aqueous H2S corrosion of mild steel much more difficult. In the present study H2S corrosion mechanisms were experimentally investigated in short term corrosion tests (1-2hr), conducted in 1 wt% NaCl solution at different pH (pH2 to pH5), at different temperature (30°C to 80°C), under various H2S/N2 concentration ratios (0-10%) and flow rates, using a X65 mild steel rotating cylinder electrode. Corrosion rates were measured by linear polarization resistance (LPR). Corrosion mechanisms were investigated by using potentiodynamic sweeps and by comparison with electrochemical modeling. LPR results showed that corrosion rates increased with increasing temperature, partial pressure of H2S, flow rate and decreasing pH. Results of potentiodynamic sweeps show the presence of H2S could affect both cathodic reactions and the anodic reaction. A new electrochemical model was developed and can be used to predict the effect of temperature, pH, pH2S and flow on corrosion mechanisms of mild steel in aqueous solutions containing H2S.

Subfields: Electrical and Electronic Engineering, Materials Chemistry, Mechanical Engineering

View Paper: https://www.semanticscholar.org/paper/89acfd3e25e4df6389e1a0906633b39b84986ae1