How to prevent corrosion of valves or drain valves on hydrogen pipelines, and what materials are suitable?
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Valves or drain valves on hydrogen pipelines have become rusted after some time of operation; how can corrosion be prevented, and what materials are suitable for this purpose?
Rusting occurs when the external anti-corrosion measures are not adequate; preventing rusting involves applying paint. Generally, rusting occurs when the temperature is not high, or perhaps in high-temperature valves during periods of shutdown or inactivity. For the selection of materials for hydrogen valves, carbon steel is used when the temperature is below 200°C. When the temperature is above 200°C, the material is chosen based on the hydrogen partial pressure and design temperature in accordance with the Nelson curve; if hydrogen contains hydrogen sulfide, the Cooper curve must also be taken into consideration. For specific details on material selection, refer to SH/T 3059.
The surface corrosion protection isn’t proper, I guess; for normal hydrogen service conditions, carbon steel is sufficient, with just painting or powder coating on the surface.