Large-diameter pipes transporting media containing hydrogen sulfide (H2S) must be resistant to hydrogen-assisted damage such as Sulfide Stress Cracking (SSC) and Hydrogen Induced Cracking (HIC). Historically, resistance to SSC and HIC has been considered in the transport of wet sour oil or gas. Line pipe steels are qualified for use by testing small-scale specimens in the standardized NACE test methods TM0316 for SSC and TM0284 for HIC.

While pipelines for sour service conditions above 1 bar partial pressure of H2S have gained attraction, pipeline transport of carbon dioxide (CO2) captured from industrial processes has recently also come into focus within carbon capture, utilization and storage (CCUS) projects, where the presence of H2S requires attention when capture techniques result in non-negligible contents of this impurity.

This paper gives an overview of recent laboratory SSC and HIC test results in autoclaves under increased H2S partial pressure. While in SSC tests for sour service, H2S and CO2 contents of the intended sour service conditions were considered, HIC tests related to dense phase CCUS had to take the complex interactions between the components in the gas-free CO2-H2S-water system into account and were therefore performed in dense phase CO2 containing H2S and other impurities typical of anthropogenic CO2.

In the context of both sour service and CCUS, the performance of different large-diameter pipe steels under critical levels of H2S is compared and discussed.