Re: Alternative Energy Sources

Dan Clemmensen (
Wed, 03 Sep 1997 20:53:01 -0400

Pat Fallon wrote:
> I showed the thread on alternative energy sources to a friend of mine (Jamie
> Naizby), and he had the following comments:
> The person talking about hydrogen flammability limits was very likely confusing
> hydrogen in oxygen limits with hydrogen in AIR limits... two very different
> situations. Yes, flammability limits in OXYGEN are from 4.7 to 15 and 90 to 93.9
> with detonation limits in between (15 to 90% by volume) BUT this is good! It is
> one of the reasons it is a vastly superior fuel to all others in use now..
> The flammability limits of hydrogen in AIR are 4.0 to 18.2 and again above
> detonation limits at from 58.9 to 75% with the 18.2 to 58.9% by volume zone
> between the detonation limits this is a fuel it has to burn to work. Propane
> in use everywhere with hardly anyone objecting has DETONATION limits from 2.1
> to 9.5 in AIR! (would prefer to use hydrogen)
Sorry about that. I was responding with a recollection
of hearsay instead of checking some sources. Thanks for the
correction. However, I still seem to recall that the big concern
with hydrogen included the risks of explosion when transported
in pipelines. Does anyone have a reference for this?

Note that there is a lot less hydrogen in a bettery-type fuel cell
(i.e., one in which consumes electricity to produec hydrogen, then
later used the hydrogen to produce electricity) than there is in
a pipeline, so the safety engineering is probably more tractable.