• Roger Penn

    October 13, 2022 at 12:49

    Moisture in the hydrogen supply at a hydrogen refueling station (HRS) is a legitimate concern. If the water enters the vehicle system and freezes, it can keep valves open and cause other problems. For this reason, the hydrogen purity standard, ISO 14687, requires the HRS to provide H2 with only 5 ppm of water in the gas feed (the SAE standard J2719, also only allows max 5 ppm of water).

  • Hermann Huber

    October 13, 2022 at 16:29

    In my H2 system, I attach great importance to a high proportion of moisture, because water has various positive influences on combustion in the engine.

    1. If H2 and oxygen are brought together in the combustion chamber, there is a high risk of backfire if the H2 is too dry.

    2. A high proportion of water in the gas increases the formation of steam during combustion and steam is energy.

    3. High vapor formation lowers the combustion temperature and is therefore gentle on the engine.

    4. At over 800° degrees, additional H2 is produced from steam through thermolysis.

    5. High humidity in gas reduces susceptibility to knocking.

    I consider the disadvantages of possible frost to be solvable with integrated warming solutions in the system. The self-heating during the electrolysis counteracts the cold.

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