Material Selection for Carbon Capture and Storage Infrastructure

Corrosion and integrity issues are significant concerns in Carbon Capture and Storage (CCS) infrastructure. Corrosion can occur at various stages of the CCS process (capture of carbon dioxide emissions from industrial processes or power plants, followed by compression, transport, and storage of the captured CO2 in underground geological formations) and pose risks to the integrity and safety of the infrastructure. The first step in material selection for CCS (Carbon Capture and Storage) infrastructure involves identifying potential damage mechanisms that may occur during the capture, compression, transport, and storage processes. Corrosion processes that occur within these environments are often influenced by the contaminants present in the streams processed/transported.

Typically, flue gas streams generated by various industries can contain a range of impurities, such as SOx, NOx, HCl, hydrogen sulfide (H2S), O2, Ar, N2, H2, CO, CH4, water (H2O), ammonia, chlorides, cyanide, and mercury (Hg). The presence of these impurities can vary depending on the fuel sources used, the combustion methods employed, and the specific CO2 capture technologies being utilized.

A high-level material selection for CCS infrastructure could be summarized below. However, it is recommended to conduct a formal analysis with the help of an expert in material selection based on each stream’s composition and select the suitable material.

Dry CO2 can be handled using carbon steel, while wet CO2 may still be managed with carbon steel by incorporating sufficient corrosion allowances. However, if the stream contains acidic components like SO2 or chlorides at certain concentrations, it might be necessary to consider lining/cladding the equipment (knock-out drums, coolers) with CRA materials such as 316L or 317LMN or made of CRAs, depending on the impurity concentrations. Other cracking mechanisms affecting Carbon steel materials could be mitigated by weld hardness control and/or post-weld heat treatment (PWHT).

In the context of CCS infrastructure, 316L SS could be used in many areas where carbon steel cannot be used. However, careful evaluation is needed to ensure cracking conditions exist for the use of 316L SS. If chlorides (>50 ppm) and/or oxygen are present in the system, it is always recommended to upgrade to 904L or super austenitic SS with 6% Mo or higher.

High-temperature mechanisms are mostly active in the shift reactors and associated piping in the precombustion scheme. Use of higher chromium stainless steels such as 309SS, 310SS, or stabilized grades like 321SS and 347SS for coal-fired pre-combustion scheme shift reactors may be required dependent on the impurity concentrations.

The following table provides a summary of damage mechanisms and corresponding international reference standards that explains the mechanism in detail and suitable material choices.

For pipeline damage mechanisms and material selection, please refer to my other blog post on why is it important to minimize the water content in dense phase CO2 pipelines?

For an injection well damage mechanisms and material selection, please follow this blog for an upcoming article.