Corrosion Mechanism of L360 Pipeline Steel Coated with S8 in CO2-Cl− System at Different pH Values

Abstract

The corrosion behavior of L360 pipeline steel coated with or without elemental sulfur (S8) in CO2–Cl− medium at different pH was studied. An autoclave was used to simulate the working conditions for forming the corrosion scale, and an electrochemical workstation with a three-electrode cell was used to analyze the electrochemical characterization of the corrosion scale. A wire beam electrode was used to determine the potential and current distribution, and scanning electron microscopy and X-ray diffraction were used to characterize the morphology and composition of the corrosion scale. The results showed that the deposition of S8 on the surface of the electrodes caused serious localized corrosion, especially under acidic conditions. The morphology and localized corrosion intensity index further proved that the deposition of S8 significantly promoted corrosion, especially pitting corrosion. Finally, a novel corrosion mechanism of L360 pipeline steel coated with S8 in a CO2-Cl− environment under acidic conditions was proposed, and we then modeled the theoretical mechanisms that explained the experimental results.

Mechanism and anti-corrosion measures of carbon dioxide corrosion in CCUS: A review

“… 59 ) Copyright 2021, John Wiley and Sons; (C and D) (Wang et al. 60 ) Copyright 2021, John Wiley and Sons; (E and F) (Zhu et al. 61 ) Copyright 2019, Springer Nature.…”

“…In CO 2 -Cl − medium with the presence of elemental sulfur, the deposition of elemental sulfur on the electrode surface can cause severe local corrosion, particularly under lower pH because the presence of sulfur and CO 2 accelerates corrosion through direct reactions with the metal substrate or through hydrolysis to form acids. 60 Figures 6 C and 6D show the polarization curves of the bare electrode and sulfur-coated electrode at different pH levels. The presence of sulfides is more likely to induce surface cracking and unevenness.…”

Advances in Corrosion and Protection of Materials

“…Wang et al [7] evaluated the effect of pH on the localized corrosion behavior of the L360 pipeline steel with and without S8 coating in a typical sour-simulated environ-ment. An innovative wire beam electrode (WBE) was employed for studying the local corrosion processes.…”

Corrosivity relationship for management of buried pipelines: A case study of Rivers state, Nigeria

“…The kind or type of the surrounding formation, as well as the solution contained inside the pipeline have an impact on this. The condition of the formation water informs how acidic or alkaline the sediment will be (Wang et al 2021); pH affects the rate at which the pipeline corrodes. According to (Arriba-Rodriguez et al 2018) 0 to 5, 5 to 6.5, 6.5 to 12, and greater than 12 represent severe, moderate, neutral, and low corrosivity on the pH scale.…”