Effect of H2S on the Occurrence of Hydrogen Induced Cracking in SAWL Pipes Designated for CO2 Transport within CCUS Projects

Abstract Pipeline transport of CO2 captured directly from industrial processes to further utilization and storage sites is a fundamental part within CCUS projects. Understanding the effect of the several possible impurities in the CO2 stream on pipeline corrosion is a key factor for establishing safe operational limits for contaminants and for limiting highly expensive purification processes. The effect of Hydrogen Sulfide (H2S) on the formation of Hydrogen Induced Cracking (HIC), which is known to be a serious concern in sour gas pipelines, has not received adequate attention in the context of CCUS projects and has therefore been investigated within this study. HIC tests were performed at lab scale in aqueous test solutions containing mixtures of CO2 and H2S and resistance limits based on pH and H2S concentration could be established for SAWL large-diameter pipe of grade X65 and X70. The results were compared to resistance tests performed in liquid CO2 under operating conditions up to 20 MPa containing H2S and other impurities with a focus on the amount of water present with or without a separate water phase.