Sorry for the late post, but I am now about 400 articles behind on my
reading.
On Jun 14, 2008, at 6:54 AM, Jones Beene wrote:
[snip]
5) There is a mystery ingredient which needs to be
replenished periodically. Unlike the gallium-aluminum
process from Purdue University, recently announced
which does split water:
http://www.autobloggreen.com/2007/05/16/purdue-professor-on-the-
aluminum-enabling-hydrogen-economy/
this one (reportedly) does not rapidly consume the
secret ingredient.
... which could be a catalyst for redundant ground
states ... or not.
It will be interesting to see what happens...
Jones
The above article states: "Woodall says that the reaction of aluminum
with water has the same energy content per unit weight of oil, about
20,000 BTUs or about 6 kWh per pound"
That's a fairly rapid consumption rate, and reminds me of a post I
made here in 2002, which follows.
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
[From the initiating article of the thread:
Down with hydrogen economy, up with aluminum economy]
On Feb 6, 2002, at 4:22 AM, Horace Heffner wrote:
Here is some fuel for thought! 8^)
The CRC Handbook gives the Gibbs energy of formation for Al2O3 and
H2O in kJ/mol as follows:
Al2O3: -1582.3 kJ/mol
H2O: -228.6 kJ/mol
Given atomic weight of Al is 26.98, and H is 1.007, we have the
following output per gram of input for the two fuels:
Al2O3: (-1582.3 kJ/mol)/(2 * 26.98g/mol) = 29.32 kJ/g
H2O: (-228.6 kJ/mol)/(2 * 1.007g/mol) = 113.5 J/g
Though only about 1/4 as efficient as hydrogen for energy storage by
weight, aluminum is far easier and safer to store and transport, and
29.32 kJ/g, or 30 MJ/kg, is very acceptable. At 7.14 g/cm^2 density,
Al provides (30 kJ/g)/(7.14 g/cm^3) = 4.11 kJ/cm^3, or 4.11 MJ per
liter of Al, a very acceptable amount. That's 1.14 kWh, or 1.52 hp
hours, enough to run a 1.52 hp motor for an hour. At a typical 7 hp
cruising speed that is a fuel consumption of (7 hp)/(1.52 hp h/l) = 5
l/hr. If the vehicle maintains 50 mph, then the fuel consumption is
(50 mi)/(5 l) = 10 miles per liter of fuel. A 100 mile fillup would
consist of 10 liters of fuel, or 71.4 kg of fuel.
If we obtain the energy from the aluminum by pyrolisis, then we have
the side benefit of obtaining hydrogen for either immediate
recombination with air, or for temporary high pressure storage.
Electrolysis, a bit mysteriously, seems to work just as well, or even
better, in terms of mol/amp and mol/J, at high pressures as at low
pressure. Using pyrolisis also permits us to more directly obtain
energy from breaking and to convert it to heat, which can be used to
drive a motor for charging a battery, and to produce high pressure
hydrogen for storage.
Since the pyrolisis of Al removes the oxygen from water, the hydrogen
is evolved at the rate of 3 mols of H per mol of Al, thus 3(-228.6 kJ/
mol) is produced for each (-1582.3 kJ/mol) of Al, or an extra 685.8
kJ per 1582.3 kJ produced from Al oxidation, or an about 43.3 percent
extra energy from the evolved hydrogen. This raises the apparent
energy output of the Al to 41.93 kJ/g.
All the heat produced in a well insulated pyrolisis cell, including
resistance heat from the electrolysis current, is converted to either
steam or evolved gas. If effective use of the steam can be made to
drive an engine, then the process should be very efficient for
transportation purposes. Energy tapped off the output to drive the
pyrolisis would be fed back to the input side. The vehicle
efficiency then depends fully on the efficiency of the steam engine
or sterling engine employed.
The powdered aluminum oxide effluent that is produced can be filtered
and collected for recycling at fill-up stations.
Magnesium would work too, but is toxic, and berylium would provide
more kJ's per gram, and the largest MJ/m^3 of any chemical fuel, but
is toxic. Aluminum is common. Even aluminum cans can be recycled
into fuel.
Up with the aluminum economy!
Best regards,
Horace Heffner
http://www.mtaonline.net/~hheffner/
