• Pressure relief best practice

    Posted by Henrik Gunnarsson on November 1, 2022 at 13:14

    What is best practice regarding pressure relief on the high pressure and low pressure side of a hydrogen stack of gas cylinders placed outside (many bottles of 140 litres each serving an industry application ) ? Also interested to learn if this differs between different countries and standards!

    Olaf Schulenberg replied 1 year, 7 months ago 2 Members · 4 Replies
  • 4 Replies
  • Olaf Schulenberg

    November 2, 2022 at 07:28

    Dear Henrik,
    if you will put the bottles togehter as as one, all bottles communicates, so that it looks like one big pressure vessel you cann install one pressure relief valve (PRV). You have to make sure that there is no possibility to close any line from the bottles to the PRV. The bad thing is, that you have to use a bigger valve size due to the high volume of all bottles togehter.
    So it makes sense to build groups of bottles togehter and to install a PRV for the group.
    For a safe function of the PRV it has to be considered that the pressure drop of the inlet and outlet pipelines to the PRV is not to high. For Inletline 3% of the set pressure and for the outletline 10%.
    This works in Installations in Europe acc. to PED (2014/68/EU). If you need any ssistance on the calculations please feel free to contact me.

    • Henrik Gunnarsson

      November 2, 2022 at 08:07

      Thanks a lot Olaf! Very good answer!

    • Henrik Gunnarsson

      November 2, 2022 at 08:40

      Dear Olaf!

      A follow-up question: Are there situations when a pressure relief is not necessary or best pracitice in your opinion/experience?

  • Olaf Schulenberg

    November 2, 2022 at 12:09

    Hi Henrik,
    I only see this opportunity if there is absolutely no event of overpressure possible in the bottles. The interesting thing is then, what will happen in case of fire. Most bottles are equipped with an TPRD for temperature raising reasons. But if the bottles are installed stationary, they need to have an pressure releif valve.
    Please send me any information if you need any further help or calculations by Email: o.schulenberg@goetze-armaturen.de
    All the best

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