Posted on 05/18/2007 10:29:42 AM PDT by NormsRevenge
CHICAGO (Reuters) - Pellets made out of aluminum and gallium can produce pure hydrogen when water is poured on them, offering a possible alternative to gasoline-powered engines, U.S. scientists say.
Hydrogen is seen as the ultimate in clean fuels, especially for powering cars, because it emits only water when burned. U.S. President George W. Bush has proclaimed hydrogen to be the fuel of the future, but researchers have not decided what is the most efficient way to produce and store hydrogen.
In the experiment conducted at Purdue University in Indiana, "The hydrogen is generated on demand, so you only produce as much as you need when you need it," said Jerry Woodall, an engineering professor at Purdue who invented the system.
Woodall said in a statement the hydrogen would not have to be stored or transported, taking care of two stumbling blocks to generating hydrogen.
For now, the Purdue scientists think the system could be used for smaller engines like lawn mowers and chain saws. But they think it would work for cars and trucks as well, either as a replacement for gasoline or as a means of powering hydrogen fuel cells.
"It is one of the more feasible ideas out there," Jay Gore, an engineering professor and interim director of the Energy Center at Purdue's Discovery Park, said in a telephone interview on Thursday. "It's a very simple idea but had not been done before."
On its own, aluminum will not react with water because it forms a protective skin when exposed to oxygen. Adding gallium keeps the film from forming, allowing the aluminum to react with oxygen in the water, releasing hydrogen and aluminum oxide, also known as alumina.
What is left over is aluminum oxide and gallium. In the engine, the byproduct of burning hydrogen is water.
"No toxic fumes are produced," Woodall said.
Based on current energy and raw materials prices, the cost of making the hydrogen fuel is about $3 a gallon, about the same as the average price for a gallon of gas in the United States.
Recycling the aluminum oxide byproduct and developing a lower grade of gallium could bring down costs, making the system more affordable, Woodall said.
However - the gallium is not used up - it’s a catalyst. and the aluminum is turned into alumina - which can be re-smeltedback into pure metal alloy.
How does the car perform in winter when the water in the tank is frozen?
Also, would you have to manufacture expansion joints in the tank to allow for the ice to expand and prevent the fuel tank from rupturing?
The technology is interesting even if it doesn’t actually get to the general marketplace.
True. I think the talk of using it to power cars may just be a way to grab attention. The practical applications might be less... profound.
Right, we discussed that.
Yes, I do not know how you could have combustion in our nitrogen rich air and not generate NOx. Maybe if the combustion was at relatively low temperature, but then it would not be effective as an energy source.
What about the other costs?* It appears that they haven’t factored in the costs of taxes, and transporting, and retailing the hydrogen fuel. If they can get the cost per mile driven to match that of gasoline — then this could be one more useful alternative.
(*Assuming that they meant that the hydrogen would have the energy equivalent of a gallon of gas.)
“Hydrogen is seen as the ultimate in clean fuels, especially for powering cars, because it emits only water when burned.”
And when it burns, boy does it burn!
The catalytic exhaust converter would have to be retained.
If thats the case then a gallium-coated vessel may well provide equally effective catalysis. I wonder if poisoning
of the gallium catalyst occurs over time?
Yeah, I keep neglecting that combustion takes place in AIR, not in combination with Oxygen alone.
Yep, I've been on projects where we put Catalytic exhaust converters on 15,000 Hp Turbines (Natural Gas Pipeline Compressor Stations).
I still say that hydrogen is not the answer. We will be on electric vehicles before there is a "hydrogen economy." And even then, combustion engines will be around for a long time. Things such as airplanes, power plants, they all use combustion engines. You can eliminate that by using Nuclear power. But then you still have airplanes, and I imagine unless we have some breakthrough technology, they will be running on hydrocarbons for a long time to come.Thanks for the ping. Great post.
Add one more big CON,
It takes a tremendous amount of electric energy to refine aluminum oxide back into pure aluminum. There is no free lunch in this save energy deal.
If you take calcium and pour water on it you get hydrogen and calcium hydroxide. I should know. In an unsupervised high school chemistry experiment I used this reaction to create a hydrogen torch. It came to an unfortunate end when a stopper popped out of a flask and sprayed me with said calcium hydroxide.
Why not calcium since it doesn’t require gallium?
Note:
If you are going to store you energy in aluminum, the worst thing you can do is convert it to hydrogen. See my post above.
Pure potassium is much more fun when water is applied. Take one pound pure potassium, insert into a flask in pea sized chunks, insert a stopper with two holes, insert a glass tube into one to inject water onto the pellets, insert a glass tube in the other to carry away the hydrogen.
Use a flame hood when applying a bic lighter to the device.
Just ask the Bonneville dam during WWII. Bonneville dam - Alcoa - Boeing - Bombers - WWII won.
Our teacher kept the sodium and potassium locked up.
One of his favorite tricks to impress the class was for us to all go outside where he would set down a pan of water and then throw in a pea sized piece of sodium. A split second later there was a explosion as the exothermic reaction of the sodium producing hydrogen ignited said hydrogen. I seriously doubt that he’d be allowed to do that today.
I remember the sodium was so reactive that it was stored in a metal can and submerged in kerosene. I figured that since calcium is far less reactive it might be a better choice.
But besides the cost of making these pellets, how much energy from other sources is required to make them? Is there a net gain in energy or a loss?
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