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.
Highlights
Accepted: 3 December 2021During the exploitation of oil and gas, some solid particles are deposited on the surfaces of pipelines owing to a decrease in the flow rate and pressure [1]
A yellow powder of S8, is an inorganic sediment generated by the catalytic pyrolysis product of ferrous sulfide under a high temperature and high pressure at the reservoir and deposited due to the reduction in temperature and pressure in the process of fluid production [5]
The fused sublimation sulfur was coated on the electrode surface, and its thickness was controlled within 1.0–1.5 mm by 2000# sandpaper grinding to ensure that there were no cracks in the sulfur layer and the working area of the electrode was covered by the sulfur layer
Summary
During the exploitation of oil and gas, some solid particles are deposited on the surfaces of pipelines owing to a decrease in the flow rate and pressure [1]. Under deposit corrosion (UDC) usually occurs and is driven by the differences in the chemistry at the interface between the sediment, the substrate, and the bulk solution. This can cause catastrophic failures, such as a reduction in the equipment’s integrity and pipeline perforation, because UDC is difficult to detect [2,3]. The chemical equilibrium reaction was changed in a high-temperature and high-pressure environment, and the decomposition of polysulfides into elemental sulfur and hydrogen sulfide was promoted
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
