(81b) Ensuring Natural Gas Infrastructure is Suitable for Hydrogen Service

Many industries globally are investing in hydrogen technologies to address ongoing climate and sustainability challenges. One potential limitation of the future hydrogen economy is whether current delivery infrastructure is compatible with transporting hydrogen gas. While there are extensive local, regional, and global pipeline networks suited for the transportation of natural gas, pipelines dedicated to hydrogen distribution are much more limited. One method of utilizing the natural gas distribution system to transport hydrogen is to blend hydrogen into natural gas pipelines and implement separation and purification processes to provide purified hydrogen and natural gas for end users. Hydrogen/natural gas blends (less than 5-15% hydrogen) have also been proposed to reduce reliance on natural gas and decrease greenhouse gas emissions.

Industry recognizes that hydrogen gas can cause specific damage to distribution network components (including embrittlement and blistering), which is not experienced within certain materials when transporting natural gas. Operators who comply with recognized and generally accepted good engineering practices (RAGAGEP) may choose to design and construct their natural gas pipelines in compliance with ASME B31.8 Gas Transmission and Distribution Piping Systems and their hydrogen pipelines in compliance with ASME B31.12 Standard on Hydrogen Piping and Pipelines. However, as operators begin to consider blends of hydrogen and natural gas, it may be unclear which standard is applicable to their operation and what gaps related to assuring mechanical integrity may develop as operators transition to shipping hydrogen/natural gas blends through their natural gas distribution systems.

This presentation and paper will review the hazard and risk factors related to hydrogen and natural gas pipeline distribution. The material properties of hydrogen/natural gas blends and the materials of construction of the distribution system will be reviewed to address the key properties that impact the hazard and risk factors. Finally, a review of ASME B31.8 and ASME B31.12 will be provided with guidance on the key differences that are applicable to hydrogen/natural gas blends. The paper will also present a methodology used to identify compliance gaps and mitigate deficiencies that arise from transporting hydrogen/natural gas blends in natural gas distribution systems.