Integrity management of pipelines transporting anthropogenic CO2 have similarities to existing CO2 pipelines, which largely transport geologic CO2, along with key differences. One important difference is the presence of dilute H2 in anthropogenic CO2 streams from ammonia plants and steel manufactures. Hydrogen partial pressures as low as 1bar in dense phase CO2 have been shown to decrease the fracture toughness of modern HF-ERW line pipe seam welds to ~1/3rd their in-air value. Additionally, emerging research using laboratory coupon scale tests has indicated that these same dilute levels of H2 may promote static crack growth (da/dt) in both vintage and modern line pipe steels. Properly assessing the probability of seam weld failure will be an important aspect of operating CCS pipelines transporting anthropogenic CO2. This requires characterization of line pipe fracture toughness in anthropogenic CO2 service. This presentation will review recent fracture testing results on a modern anthropogenic CO2 CCS pipeline network, with data from multiple suppliers and grades. The benefits of testing best practices will be discussed as will the impact of specimen geometry and static load-hold material response. Work in progress, including full scale testing, to better understand line pipe material response in anthropogenic CO2 environments will be shared.
