Sunday, June 26, 2011

Storing Hydrogen Safely

Metal hydrides could potentially play a leading role in a hydrogen economy. By Virginia Heffernan

I got the idea to do this from an earlier post about the ratio between hydrogen and nickel. That is, if the ratio is 1 to 1 in terms of atoms, then it would be effectively much higher pressure per volume of the solid nickel ( according to the Ideal Gas Law). So, I find this article, and it gives a number, but it is not entirely clear what it means.

Many alloys form hydrides with up to 9% hydrogen but will release the gas only at extreme temperatures.
Does that mean by weight or what?  At 9% by weight, it would be greater than 1 to 1 because hydrogen is only about 1/30th the mass per mole ( and even that takes into account the fact that hydrogen bonds with itself, so the true ratio would be 1/60th).  That could mean multiple atoms of hydrogen per nickel atom.

As Spock would say on Star Trek:  "fascinating".  This means the equivalent of very high pressures, I would think.  It would mean up to six moles of hydrogen per mole of nickel, with the nickel occupying only a tiny fraction of the volume that would have been the case with hydrogen alone.  This gives a very high theoretical pressure per volume, per the Ideal Gas Law.

You may recall the equation for the gas law:  pv=nrt.   As temperature increases, so must pressure.  If it approaches a billion degrees kelvin and is still inside the nickel, the pressure would be very high indeed.  Each side of the equation would have to rise proportionally, you see.  A billion degrees is 10^9th.

So, Huizenga doesn't think this can cause fusion?  It almost seems comically false to me.  He's gotta be pulling somebody's leg. 

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