Extended design philosophy of hydrogen transport pipelines

This paper examines some specific design issues associated with hydrogen transportation via pipelines based on recent field development study of high-throughput hydrogen pipelines. A mechanical design review is undertaken, and the current design practices and challenge are examined first. An array of key parameters considered to have significant bearing on the hydrogen pipeline general mechanical design are considered and assessed, including out of roundness (OOR) imperfections, combined stress and design factors, thermal gradients, joint mismatch and fabrication, fatigue assessment, installation, specifications and material consideration. Some of these are typically ignored for the conventional pipeline design, but open to rationalization for hydrogen charged pipeline systems subject to material embrittlement risk arising from hydrogen absorption. Complementary to the current design standards and as a spur to discussion on the hydrogen pipeline design analysis, special considerations and recommendations are proposed on materials specification, additional design criteria and construction assessments, and their rationale to mitigate material embrittlement with a view to improving hydrogen pipeline design, reliability and integrity management potentially leading to some tangible cost saving.