Films Formed on Carbon Steel in Sweet Environments - A Review

Abstract

Corrosion of carbon steel pipelines in sweet environments has been extensively researched on oil and natural gas exploration and production in order to obtain efficient corrosion mitigation methods. Although the consequences of corrosion are known, the cause and mechanism by which a certain phenomenon occurs are still not well understood. Sweet corrosion is mainly caused by the carbon dioxide dissolved in the water contained in the oil. It can manifest itself in different ways and one of which is the formation of a scale on the inner walls of the pipelines, which determines the evolution of corrosion process. This paper discusses the effects of partial pressure of carbon dioxide, dissolved hydrogen sulfide, dissolved oxygen and water chemistry on scale formation. Particular attention is paid to the nature and stability of the aqueous species formed during the corrosion process, as well as the thermodynamic and kinetic aspects lead to the scale formation on the carbon steel surface. The main objective is to enhance the understanding of the conditions of formation and precipitation of siderite and mackinawite and their effects on corrosion processes involving low carbon steels.

Electrochemical and Computational Insights on the Application of Expired Metformin Drug as a Novel Inhibitor for the Sweet Corrosion of C1018 Steel

“…There is a resultant decrease in the i corr from 47.70 (without MET) to 4.33 μA cm –2 (with 200 ppm MET), and this yields an inhibition efficiency as high as 86.31%. Here, it is noteworthy to mention that this inhibition efficiency is considerably higher compared to that noted by earlier authors at higher concentrations. , Furthermore, this high inhibition efficiency is remarkable considering that in the present study the investigations have been carried out in the presence of acetic acid, which is known to increase the corrosiveness of 3.5 wt % NaCl in the presence of CO 2 . Although the MET addition shifts the anodic and cathodic arms of the PDP curves toward lower values, it can be clearly seen that the effect of MET on the cathodic current is more obvious than its effect on the anodic current.…”

“…22,59 Furthermore, this high inhibition efficiency is remarkable considering that in the present study the investigations have been carried out in the presence of acetic acid, which is known to increase the corrosiveness of 3.5 wt % NaCl in the presence of CO 2 . 60 Although the MET addition shifts the anodic and cathodic arms of the PDP curves toward lower values, it can be clearly seen that the effect of MET on the cathodic current is more obvious than its effect on the anodic current. MET can, therefore, be regarded as a more cathodic-type inhibitor.…”

Promoting electrocatalytic overall water splitting by sulfur incorporation into CoFe-(oxy)hydroxide

“…61 Coprecipitation of Co(OH) 2 and Fe(OH) 3 forms (Co, Fe)OOH on the iron foam surface after drying at high temperature. The chemical reaction for the synthesis of (Co, Fe)OOH can be described using Eq.2-5: 62 Fe + Co 2+ → Fe 2+ + Co (2)…”

“… 61 Coprecipitation of Co(OH) 2 and Fe(OH) 3 forms (Co, Fe)OOH on the iron foam surface after drying at a high temperature. The chemical reaction for the synthesis of (Co, Fe)OOH can be described using eqn (2)–(5) : 62 Fe + Co 2+ → Fe 2+ + Co Co 2+ + 2H 2 O → Co(OH) 2 + 2H + O 2 + 2H 2 O + 4e − → 4OH − 2Fe 2+ + 4OH − → 2Fe(OH) 2 4Fe(OH) 2 + O 2 → 4FeOOH + 2H 2 O …”

Substrate Protection with Corrosion Scales: Can We Depend on Iron Carbonate?

“…One issue that plagues this industry is infrastructure degradation through corrosion, which can undermine economic viability, as well as increase the probability of catastrophic failure. − On this basis, immense effort is being applied to explore routes to control this phenomenon with an increasing emphasis on lower environmental impact solutions, , such as harnessing naturally formed corrosion scales. For instance, it is proposed that the barrier properties of scales formed on carbon steel in aqueous CO 2 -saturated (sweet) environments, − encountered in geothermal power plants, carbon capture facilities, and oil production, can mitigate corrosion. Here, we test this hypothesis, providing experimental evidence to suggest that even the protection afforded by intact sweet corrosion scales may be undermined by spatially localized corrosion, so that they cannot be relied upon alone for structural integrity.…”