H2 deflagration

[Bill3752]

I have a reactor consuming hydrogen. The MAWP is 90 psig. The NFPA Pmax ~ 87 psig and Pred ~136 psig. Because the Pmax is lower than the MAWP, does this mean that the vessel will contain a deflagration - i.e. that we do not need to install rupture discs for this scenario?

 

[georgeverghese]

What about transient pressure caused by detonation ? - this will be much higher than deflagration generated pressures

 

[Bill3752]

George, good question. I will need to look at this. Because L/D is ~2, I don't think detonation is likely a problem in the reactor itself, but i suspect it needs to be looked at in the piping to/from, where lengths are long.

 

[MortenA]

I think NFPA is for dust? But maybe also for gasses? Anyway, for dust the NFPA must be added to the operating pressure - so unless yout reactor is operating at ATM it should be safe for containing an explosion. I dont know wrt a detonation though at George mentions.