Since the hydrogen release pipelines are all non-steady-state fluids, isn’t it necessary to comply with the flow rate restrictions specified in the Hydrogen Station Code GB50177?
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As the title suggests, I would like to ask the experts: since the hydrogen release pipelines involve unsteady-flow conditions, cannot the flow velocity limits specified in the Hydrogen Station Code GB50177 be applied? According to the calculations, the flow velocity after the safety valve reaches 50 meters per second. Is it necessary to keep this flow velocity within 15 meters per second, as required by the standard GB50177 for carbon steel pipelines? I would appreciate expert advice on this matter; please also indicate the source if possible. A comprehensive answer will be greatly appreciated. :handshake
Although hydrogen vent pipes involve unsteady flow, they still need to comply with the relevant guidelines and restrictions specified in the safety standard GB50177, including limits on flow velocity. Although the flow velocity behind the safety valve can reach 50 meters per second in actual calculations, to ensure safety, in accordance with the GB50177 standard, the flow velocity in carbon steel pipes must still be kept below 15 meters per second. This is done primarily to avoid pipe vibration, increased noise, and potential damage risks caused by excessive flow rates. .
GB 50516-2010 (2021 edition) – Technical Specifications for Hydrogen Refueling Stations, 6.5.3C, Clause 2: The flow velocity of saturated liquid hydrogen shall not exceed 16 m/s, and the flow velocity of single-phase hydrogen gas shall not exceed 150 m/s
The outlet of the safety valve is normal at 100 m; what matters is the Mach number. As for the impact of static electricity, it’s necessary to ensure proper grounding, and a flame detector should also be installed – hydrogen flames are transparent and thus not visible