The global shift towards a greener energy mix is not only changing energy sources but also profoundly impacting the design and standards of critical piping components—flanges. Traditional standards dominant in oil and gas, such as ASME B16.5 and API 605, are encountering new engineering challenges in emerging applications like hydrogen and carbon capture, utilization, and storage.
Unique Challenges in Hydrogen Systems: The hydrogen molecule is exceptionally small and permeable, making it prone to causing “hydrogen embrittlement” in metals, which reduces material ductility and can lead to brittle fracture under stress. Therefore, material selection for flanges in pure or hydrogen-rich service demands extreme caution. Standard austenitic stainless steels (e.g., 304/316) may no longer be suitable, necessitating materials with superior resistance to hydrogen embrittlement, such as specially heat-treated low-strength steels or certain specialty alloys. Simultaneously, sealing requirements become more stringent, driving the focus towards metal gaskets or novel composite gaskets with excellent anti-permeability properties.
High-Pressure Corrosive Environment of CCS: Flanges in CCS projects must withstand high-concentration carbon dioxide, particularly the corrosive carbonic acid formed in aqueous environments. Furthermore, transportation of supercritical CO₂ involves very high pressures (often above 10 MPa) and potential impurities. This presents combined demands on flange strength, toughness, and internal corrosion resistance. Traditional carbon steel with coating solutions may pose risks, promoting the use of corrosion-resistant alloy-lined flanges or high-performance duplex stainless-steel flanges.
The Lag in Standardization and Engineering Practice Leads: Currently, entirely new flange standards specifically for hydrogen and CCS are still under development. Leading engineering practices rely on the “enhanced application” of existing standards. This involves establishing supplemental technical requirements—far exceeding routine specifications in material, manufacturing, and inspection (e.g., stricter hardness control and NDT)—based on rigorous risk assessments like HAZOP studies.
For project developers and EPC contractors, understanding these deep-seated impacts of new service conditions on flange technology and partnering with suppliers possessing forward-looking technical knowledge is fundamental to ensuring the long-term safety and reliability of new energy infrastructure.