Abstract
Static immersion tests of potential injection pipe steels 42CrMo4, X20Cr13, X46Cr13, X35CrMo4, and X5CrNiCuNb16-4 at T = 60 °C and ambient pressure, as well as p = 100 bar were performed for 700–8000 h in a CO2-saturated synthetic aquifer environment similar to CCS sites in the Northern German Basin (NGB). Corrosion rates at 100 bar are generally lower than at ambient pressure. The main corrosion products are FeCO3 and FeOOH with surface and local corrosion phenomena directly related to the alloy composition and microstructure. The appropriate heat treatment enhances corrosion resistance. The lifetime reduction of X46Cr13, X5CrNiCuNb16-4, and duplex stainless steel X2CrNiMoN22-5-3 in a CCS environment is demonstrated in the in situ corrosion fatigue CF experiments (axial push-pull and rotation bending load, 60 °C, brine: Stuttgart Aquifer and NGB, flowing CO2: 30 L/h, +/− applied potential). Insulating the test setup is necessary to gain reliable data. S-N plots, micrographic-, phase-, fractographic-, and surface analysis prove that the life expectancy of X2CrNiMoN22-5-3 in the axial cyclic load to failure is clearly related to the surface finish, applied stress amplitude, and stress mode. The horizontal grain attack within corrosion pit cavities, multiple fatigue cracks, and preferable deterioration of austenitic phase mainly cause fatigue failure. The CF life range increases significantly when a protective potential is applied.
Highlights
The carbon capture and storage process (CCS [1,2]) is a well acknowledged technique to mitigate climate change
If C-Mn steels are heat treated to the martensitic microstructure, grain boundaries react in a hydrogen sulfide (H2 S)-containing
Stable corrosion rates are reliably determined after 1 year of exposure [9,15]
Summary
The carbon capture and storage process (CCS [1,2]) is a well acknowledged technique to mitigate climate change. Steels used as pipes for transport or injecting into, e.g., a saline aquifer (onshore CCS site) are susceptible to CO2 -corrosion [3,4,5,6,7,8,9] influenced by: . The corrosion resistance of various steels is mostly dependent on the composition of the alloys [22] and their heat treatment [23,24,25]: Ni- and Cr reduce surface corrosion phenomena [26,27] and retained austenite reduces local corrosion [26]. The higher temperature during austenitizing of martensitic steels [28,29,30] and annealing of lean duplex stainless steels [22,23,28] decreases the potential for local phenomena. If C-Mn (carbon) steels are heat treated to the martensitic microstructure, grain boundaries react in a H2 S-containing
Sign-in/Register to view highlights & summary 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.
