Large amounts of water can be produced during the production of hydrocarbons from underground reservoirs. Salts are always dissolved in these produced waters. The concentration of dissolved salts can be as high as 400 g/l. For the first time, the effect of salt concentration on uniform hydrogen sulfide (H2S) corrosion of carbon steel in aqueous solutions is studied. Linear polarization resistance (LPR) and potentiodynamic polarization (PD) experiments were conducted in aqueous solutions at 20°C and pH 5.00 saturated with an H2S/N2 gas mixture with a total pressure of 1 bar and H2S concentration of 100 ppm(v). Two NaCl concentrations were tested: 1 and 20 wt.%. A rotating cylinder electrode with a rotational speed of 1000 rpm was used as the specimen. LPR corrosion rates indicated that H2S corrosion rate decreased with increasing salt concentration. PD results showed that the corrosion process was under mixed control. Increasing salt concentration retarded both the anodic and the cathodic reactions, and thereby, decreased the rate of uniform H2S corrosion.

Subject
Hydrogen concentration, Corrosion rate, Trends, Sodium chloride, Mixtures, Constants, Sodium chloride solution, Ion concentrations, Solutions, Salt concentration, Carbon steel, Risk reduction, Linear polarization resistance
Keywords:
hydrogen sulfide corrosion, pipeline corrosion, salt concentration, salinity, rotating disk electrode (RDE), produced water
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2022
Association for Materials Protection and Performance (AMPP)
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