Hydrogen cells

Gonz

Gonz

molṑn labé
Staff member
My science is pretty shallow. Isn't hydrogen one of the most common & one of the most volitile elements? If so, how are they gonna power a car? More importantly, how are they gonna store it in car while driving on "dangerous" roads? Someone explain so I don't have to go search google & read boring scientific research papers.:headbang:
 
I beleive the current hypothesis going is that it can be extracted from water.
 
That's right.

H2O has all you need to do it, however, in order to break water, you need a big ammount of energy that is far more than the one you would obtain. That's why it isn't viable with current technology.
 
Um no Luis.

In a fuel cell, you combine hydrogen with oxygen to produce water, heat (the reaction is exothermic), and energy. In the fuel cell you have an anode, cathode, and an electrolyte membrance. As hydrogen flows into the anode of the fuel cell, platinum coating on the anode helps to separate the gas into protons and electrons. The electrolyte membrane in the center allows only the protons to pass through the membrane to the cathode side of the fuel cell, where it reacts with the oxygen to form positively charged water. The electrons cannot pass through this membrane and flow through an external circuit to the positively charged water in the form of electric current.

This reaction occurs at about 80 degrees Celsius, or about 176 degrees Fahrenheit. A fuel cell produces about 0.7 volts, and can be chained together for a better effect.

Hydrogen is plentiful, but volatile. A spark will set off hydrogen provided there is oxygen. But think of it this way: Your gas tank also contains a pretty volatile substance. The difference is that one is a liquid and one a gas. More care is indeed needed to prevent an accident from happening. In the cars shown in Popular Science, the "gas" tank is air tight and when you fill up on hydrogen it actually compresses the air.

Or, companies use what is called a reformer. It will take certain gasses or liquids and extract hydrogen from it. Unfortunately, these reformers produce other gasses (pollution). If you could fill up on pure hydrogen, there would be no pollution (only water). But, if you use a reformer to extract hydrogen from say natural gas or methanol, you're going to have carbon as a byproduct, again.
 
I think the idea going is that the conversion can take place on the fly, so that a large amount of stored hydrogen would not be necessary, thus lessening the danger of an accident.
 
i was talking about an infinite loop of

water -> hydrogen and oxigen -> reaction -> water
 
Thanks Jerek. That's what I was after.

As far as "we can't have that" re: Luis, we can't fly either-tell that to the Wright Bros. Impossible becomes improbable becomes difficult becomes mundane.
 
We will never have that either, in a form that supplies extra energy. You're essentially breaking up water, and recombining it. The net energy is the same. However, in any reaction energy is lost. Heat, electromagnetic radiation, etc. So even if we have a PERFECT reaction with NO energy loss, there would be NO net energy unless you turned some matter into energy. :)
 
I guess we are gonna need a fusion reactor to make the energy to convert all that water to 2H and one O. I know there are ways to extract H2 that are much more efficient than electrolisis but I couldn't tell you what they are right now. In truth, fuel cells probably won't even use H2. From what I've read, methonol, natural gas, or even gasoline are more likely fuel sources.
 
RD_151 said:
I guess we are gonna need a fusion reactor to make the energy to convert all that water to 2H and one O. I know there are ways to extract H2 that are much more efficient than electrolisis but I couldn't tell you what they are right now. In truth, fuel cells probably won't even use H2. From what I've read, methonol, natural gas, or even gasoline are more likely fuel sources.
Click to expand...
It will still use H2, but it will be extracted from other fuel sources.
 
http://www.ballard.com/tD.asp?pgid=20&dbid=0

pem_fuelcell.gif
 
But that fact negates the 'perpetual loop' theory....Its like plugging an electric generator into itself....
 
regardless, there will be energy loss in friction, escaped heat, molecular reluctance, fragilstatic diffraction, aerobolic contusions, etc, etc, etc.....
 
Jerrek,

Yeah, I understand that. its basically like you stated above. The actual 'fuel' though will not likely be hydrogen, but instead, some hydrocarbon from which the hydrogen is extracted. Its only politically correct to speak of hydrogen fuel cells, because people don't like to admit that they are still gonna produce some pollution. You have to get the hydrogen from somewhere. Your 'gas tank' will likely still be full of gasoline, natural gas, alcohol, or some other hydrocarbon. Its unlikely that they will put hydrogen in the 'tank.' Maybe I'm wrong though. I guess its better for the environmentalists if you do put hydrogen 'in the tank' because then they won't 'see' the pollution. Although it will be produced along with the hydrogen. Unless of course we perfect fusion reactors, there WILL be pollution. It will just come in a different form than currently. Ok, maybe we could build something like the 3 gorges dam they are building in china, then it would be pollution free as well, assuming we built a few dozen of them ;)

It would greatly simplify the distribution of fuel to do it this way. The infrastructure is already in place, so I can't see them moving to putting H2 in the tank. It wouldn't be very efficent!
 
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