Interaction of hydrogen and fatigue on structural integrity of pipelines for hydrogen transport

氢被认为在能源转型和实现2050年净零排放目标方面发挥着关键作用。氢气输送是整个氢经济价值链不可或缺的一部分，其中管道提供了一种经济有效的氢气运输方式。特别是，重新利用现有的天然气管道是一种“输送大量氢气的低成本选择”。在高压氢气环境中，钢管道可能会发生氢脆（HE），损害结构完整性并导致管道失效。同时，天然气管道通常经历频繁的压力波动，诱发循环载荷以引起管道疲劳。目前，氢在疲劳裂纹中的作用尚未完全了解。有时会得到有争议的结果。循环载荷作用下钢对氢的吸附/吸收行为研究很少，本次国际合作的目的是研究高压氢气环境下氢和疲劳对钢管道结构完整性的影响，填补知识空白，并为管道安全输送氢提供技术建议。研究了氢在管线钢疲劳裂纹中的作用，以及在管线运行条件下（如压力波动幅度和频率、温度、内压、氢/天然气混合比和钢种），循环载荷对氢原子在管线钢中渗透和局部捕获的影响。该项目将在管道HE和疲劳研究方面开展国际合作。这些成果将有助于加速实现氢经济，促进全球能源转型和脱碳，使加拿大在氢管道技术方面处于世界领先地位。

Hydrogen is believed to play a critical role in energy transition and achievement of the 2050 net-zero emission goal. Hydrogen delivery is integral to the entire value chain of hydrogen economy, where pipelines provide an economic and efficient means to transport hydrogen. Particularly, repurposing existing natural gas pipelines is a "low-cost option for delivering large volumes of hydrogen".Safety is paramount for hydrogen transport by pipelines. Hydrogen embrittlement (HE) can potentially occur on steel pipelines in high-pressure hydrogen gas environments, compromising structural integrity and causing failures of the pipelines. At the same time, gas pipelines usually experience frequent pressure fluctuations, inducing a cyclic loading to cause pipeline fatigue. Nowadays, the role of hydrogen in fatigue cracking has not been fully understood. Sometimes, controversial results are obtained. The hydrogen adsorption/absorption behavior on steels under cyclic loading has rarely been studied.The objective of the proposed international collaboration is to investigate the interaction of hydrogen and fatigue on the structural integrity of steel pipelines in high-pressure hydrogen gas environments, filling knowledge gaps and providing technical recommendations for the safe transport of hydrogen by pipelines. The research will investigate the role of hydrogen in fatigue cracking of pipeline steels, and of the effect of cyclic loading on hydrogen atom permeation and local trapping in the steels under pipeline operating conditions (such as pressure fluctuation amplitude and frequency, temperature, internal pressure, hydrogen/natural gas blending ratio and steel grade). The project will develop an international collaboration in pipeline HE and fatigue research. The outcomes will contribute to accelerated realization of hydrogen economy for global energy transition and decarbonization, placing Canada a leading position in hydrogen pipeline technology in the world.