You could be correct Bob as I am going off of my experience with KOH and aluminum powder in a copper tube. I never had an explosion until I tried running it without nickel and Fe2O3. The explosion happened at 106C. It's probably not completely accurate to say explosion as you note. More like a significant pop shooting a copper fitting into the wall. I would tend to think there is risk of popping the cell at the lower end of the temperature range when hydrogen is initially released (assuming the gettering is not happening quick enough).
On Mon, Mar 2, 2015 at 12:31 PM, Bob Higgins <[email protected]> wrote: > I don't know why you think it would be less safe to run LiAlH4 by itself > in the reactor. As the temperature rises and H2 is released, the liquid Li > is also being released. If there is oxygen present, it will form LiOH > which doesn't decompose until over 900C. This is the first stage of O2 > gettering. Also, as the aluminum melts (660C), it will also, and extremely > stably, getter the oxygen to form Al2O3. When the LiOH decomposes and > releases the O2, it will immediately be gettered by the molten Al. > Further, molecular H2 doesn't thermally split until over 2400C, so when the > catalysts are not present to split the H2 (Ni, Fe), the pressure could be > lower. Once the Li and Al are molten, I think the molten alloy becomes > saturated with with hydrogen, probably monatomic H, causing a net reduction > in pressure, but that is just a hypothesis. When the Ni is present, there > is only a minor take-up of H - it doesn't fit easily into the lattice - so > there will only be H very near the surface and only a small volume will be > taken up by Ni. As I understand it, at very high pressures H is taken more > deeply into the metal, but still not very deep. > > There may be some danger if there is a leak, but only a small one. The > actual volume of H2 generated from the amounts of LiAlH4 being used is > fairly small (<0.5 liter STP) and if there is a leak it will come out > gradually as the LiAlH4 decomposes. If it explodes, the small STP volume > limits the chemical energy release to a mildly dangerous explosion (Bang!), > that is easily shielded. But it must have a shield! It is also going to > be a loud implusive pop, so one safety item to consider is ear plugs. Plan > for it to explode (but design it not to explode). > > Of course, the amount of LiAlH4 you put in the reactor volume to decompose > will determine the peak pressure in the reactor. This LiAlH4 mass to > volume of reactor ratio is an important one to get the pressure in the > right range for LENR. Any leaks, and the pressure will quickly go down by > orders of magnitude and the LENR will likely not occur. I say this, but we > all know that Rossi historically worked at lower H2 pressure and got LENR > at lower temperatures. So with the right catalyst, it may not need as much > LiAlH4 for the same volume and LENR could begin at a lower temperature. > > Yes, Dennis is a very creative and experienced researcher. > > Bob > > On Mon, Mar 2, 2015 at 10:42 AM, Jack Cole <[email protected]> wrote: > >> That's useful information Bob. Very creative techniques by Cravens. >> >> You probably already know this, but I would urge caution running with >> LiAlH4 alone. Expect that it will explode. Nickel and other materials >> (e.g., Fe2O3) in the cell attenuate the risk of explosion, but with only >> hydrogen producing materials in the cell, it is extremely likely >> (particularly if the oxygen has not been removed). >> >
