What type of lubricant can be use in the gas flow into a stack?

[Roger Penn]

In general, want to use water as a lubricant for hoses, O-rings etc. rather than any hydrocarbon product. Oils and greases that end up in the stack will poison the platinum catalyst and cause performance loss (which is why the air compressions for fuel cell systems are ‘oilless’).

If water doesn’t work for some reason, can use Krytox (GPL205/206) – but use sparingly and then clean exposed surfaces in contact with fluid streams. Krytox tends to stay in place or move slowly, so the further away it is from the stack inlet ports the better (for O-rings/gaskets at the actual stack ports I would stick to water if at all possible).

Hope this help. Kind regards, Roger