Posted on 05/17/2007 4:09:52 AM PDT by saganite
You can pull off a very similar process by simply dissolving some lye in water and adding aluminum foil.
Bubbles off hydrogen.
And I’m sure lye is alot cheaper than gallium.
In either case, the energy used to make the aluminum is greater than the energy gotten from the hydrogen, so more efficient batteries are a much better solution.
Well, the original poster said “oxygen” and you said “air”. Air is mostly nitrogen (77%?), which has a dampening effect on combustion. There is still oxidation happening — and those are small explosions — but the alumina coating forms and keeps the reaction in air from running away so only a very small amount of the aluminum is reacting.
The article, however, is about water rather than air or pure oxygen. Water doesn’t have the dampening effect of nitrogen, and a pound of aluminum oxidized in water produces 2kwh of heat in addition to the work done in splitting the water. That’s a lot of heat but still not the explosion you’d get if you reacted pure oxygen with the aluminum gallium mixture.
This is interesting, and not the first process that generates hydrogen “on demand” for an internal combustion engine. Electrical enerby is being used in a process to power an internal combustion engine with nascent hydrogen and oxygen. There is significantly more energy available recombining nascent hydrogen and oxygen than there is in combusting hydrogen (H2) with oxygen (O2).
“That’s legitimate...fuel is a an energy storage medium, after all...but it appears doubtful to me that this technology will ever become really competitive with fossil fuels. Not this century, anyway.”
I think the important point is that it is really dependent only on the cost of electricity, and we have many options on how to produce it. It does not depend on petroleum reserves that are not under our control, and it does not depend on choosing between food and energy uses from crops as ethanol or biodiesel does.
Those seem to be important points to me. It is true that the same can be said about batteries and electric vehicles. But this technology seems cheaper and more energy dense as a carrier than any of the battery technologies I’ve seen. According to the article, the aluminum is carrying 4.4kwh per kg ! That is compared to 0.2kwh per kg for li-ion batteries. Even including the full weight of the water and apparatus, it is still four times as energy dense as li-ion batteries.
Even at night ? I think you might have to get up much higher than the clouds. There’s the rub.
Gasoline engines already produce a lot of water vapor in addition to the CO2 produced.
So the real question is how many kilos of water vapor per mile are produced from a hydrogen vehicle (fuel-cell or ICE) compared to the equivalent gasoline vehicle ? Maybe it isn’t a lot more ?
Personally, I don’t think all that water vapor hurts the air quality here in LA at all ! I think the moisture starved landscape sucks it up before it ever becomes a greenhouse problem.
That works for LA. I live in a somewhat more humid environment.
Good point about the water vapor from gasoline engines. I’ve never seen a discussion about the advantages or disadvantages of hydrogen in that regard.
Where are you getting your numbers from ? We have daytime capacity problems, but excess electrical generation capacity at night.
http://www.eia.doe.gov/cneaf/electricity/epa/epat3p2.html
From the above DOE numbers, we have an overall 150,000MW excess generating capacity. If every gasoline vehicle in the country was replaced with either electric and charged at night, or using this aluminum oxidation tech and the aluminum was recycled at night, it would use less than half of the existing excess electrical generating capacity.
I think that that fairly obviously is true. The water, in such case, turns out to be merely a catalyst in a reaction which ultimately just oxidizes aluminum, delivering fuel to an engine or fuel cell, which gives you your water back as steam to be condensed and recycled.
Only if you "combust" it in a pure oxygen atmosphere. If you use air, you also get oxides of nitrogen, NOx.
It's also fuel we could produce right here (the Alumina can recycled), rather than subsidizing the Angry Ayatollahs and Mad Mullahs, directly or indirectly. It also reduces the need to burn valuable chemical feed stocks.
Oh okay, thanks!
Aluminum-Gallium alloy. It might be denser than aluminum, might not. Although a 350 pound block of aluminum isn't as big as you might think. Aluminum weighs 0.098 lb/in^3. Thus 350 pounds would be about 3700 cubic inches. That's a cube about 15 inches on a side. Or 30 inches x 15 inches X 7.5 inches. About the size of a gasoline tank. Put another way, that's about 15.8 gallons, again about the size of typical gasoline tank.
Except that you do have to transport the final product. Since it's solid (pellets), you probably can't move it by pipeline, which leaves trains and trucks. Highways and rail lines are even more expensive than transmission lines.
But that doesn't mean it's not a viable idea, you'd just have run the numbers.
We don’t have to spend a few hundred million bucks defending our access to the raw materials.
This time last century, well maybe a little before, they didn't think fossil fuels would replace oats as a source of power for vehicles.
92 1/2 years is a Long Time.
By then we might be getting the aluminum from the moon and using solar energy to refine it, or the Jihadies may have nuked us all by then. (Presumably we'll have nuked 'em back, unless there's a Rat President at the time, in which case we'd ask why they hate us so much).
Well, you have to go quite aways above the clouds for the sun to be always shining. I guess you could be in an orbit that precessed in a such a way as to keep in aligned with the terminator. Then you wouldn't have to so very high. Be tricky though.
Interesting!
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