Enabling the injection of hydrogen in high-pressure gas grids: Investigation of the impact on materials and equipment

Green hydrogen is a renewable gas that can help to reach the goal of decarbonizing the energy sector. The use of the natural gas grid for seasonal storage and transport of hydrogen needs previous assessment of its tolerance, ensuring safe and viable operation. In this work, the tolerance of the most typical material pipelines and key elements of high-pressure gas grids to the transport of 20 mol% hydrogen blends at 80 barg has been investigated at pilot scale. For this, the experimental campaign carried out at a testing platform replicating a high-pressure gas grid lasted 3000 h. The tightness of different kind of valves led to hydrogen losses below 1 Nml·h⁻¹. No embrittlement or other kind of damage was found on these valves or the different parts of the equipment (regulator, flowmeter) tested. C-ring, 4pb and CT-WOL specimens have been prepared from carbon steel pipes (API5L Gr X42 to X70), showing no damage after exposure to hydrogen. H₂/CH₄ deblending has also been successfully achieved using Pd-based membrane technology, obtaining a high-purity separated streams.