Effect of H₂S and CO₂ in Oil/Water Emulsions on the Corrosion Resistance of SA-543 Steel

The effect of H₂S and CO₂ in oil/water emulsions on the corrosion resistance of SA-543 steel was determined using a cell containing a rotating cylinder electrode. Electrochemical and weight loss measurements were conducted on test specimens mounted on the rotating electrode. The effect of H₂S was determined using an emulsion containing 30% oil and 70% of a 0.01 M Na₂S₂O₃ solution both in the presence and absence of CO₂. The performance of SA-543 in the presence of CO₂ was evaluated using an emulsion prepared with a 3 wt.% NaCl solution containing CO₂. The corrosion resistance of X65 steel was also investigated under the same conditions for comparison purposes. The performance of SA-543 steel was further investigated as a function of the oil concentration, rotation speed of the electrode, and temperature to determine its corrosion resistance at varying operating conditions. Results show that the corrosion resistance increases with increasing oil concentration, rotation speed, and temperature. Experimental data also indicate that SA-543 steel is a more promising material to be used in H₂S containing environments, and thus for fabricating pipes for transporting oil and gas, when compared to X65 steel.