Hydrogen embrittlement in hydrogen-blended natural gas transportation systems: A review

The addition of hydrogen to natural gas to form hydrogen-blended natural gas is an effective way to realise large-scale hydrogen transportation and promote the wide application of hydrogen. However, it deteriorates the mechanical performance of the gas transportation systems to varying degrees as a result of hydrogen embrittlement. In this review, we first introduce the composition of the hydrogen-blended natural gas transportation system in detail. We then review the phenomenon and mechanism of hydrogen embrittlement to highlight its complexity. The synergistic action and interplay of hydrogen embrittlement mechanisms, experimental and modeling approaches have been discussed; In addition, we discuss the research status of hydrogen embrittlement in existing hydrogen-blended natural gas transportation systems, including compression devices, delivery devices, welded and storage devices. In particular, we exhaustively summarise the factors that affect hydrogen embrittlement of pipelines. We also provide an overview of the measures and methods used to avoid or delay the occurrence of hydrogen embrittlement. Finally, we provide suggestions for the performance improvement of hydrogen-blended natural gas transportation systems, and propose future application prospects.