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Offline Ben6789

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« on: 16/04/2007 16:23:42 »
My science teacher told me about them. They would be much more efficient and to fill them up just grab the garden hose.And it would actually be safe to suck on a tailpipe, only oxygen would come out! ;D [O8)]

...So why aren't they being made?
« Last Edit: 16/04/2007 16:25:26 by Ben6789 »


 

Offline Seany

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« Reply #1 on: 16/04/2007 16:28:26 »
That's the problem.. You need to split the Hydrogen from Oxygen.. But energy is needed to do that.

Which means back to square one. To be able to split the Hydrogen from the Oxygen, you will need energy, which you will get from fuel! Which means Carbon emissions, which means.. We might as well carry on like now :P
 

Offline Ben6789

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« Reply #2 on: 16/04/2007 16:29:40 »
So, would some kind of fission machine in your engine to split them?

..Why not just use pure hydrogen from the start?
 

Offline Seany

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« Reply #3 on: 16/04/2007 16:39:39 »
Yes... Well how would you get Hydrogen easily? It would probably be more expensive than fuel at the moment, which is what people do not want.
 

another_someone

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« Reply #4 on: 16/04/2007 17:43:01 »
Yes... Well how would you get Hydrogen easily? It would probably be more expensive than fuel at the moment, which is what people do not want.

This is exactly the problem.  Hydrogen does not exist as a free element naturally, so you need to create it from a bound state (most likely by splitting water), which costs more energy than you would recover in recombining the hydrogen with oxygen to create water (in theory, the two would balance; but in practice, there would always be substantial inefficiencies in the system, so you would lose energy).

There is also the problem that if we had a large scale hydrogen generating facility, you would be using lots of water - and although the planet does contain lots of water, as we have seen with oil, something that you have lots of to start with, if you build a big enough industry to consume lots of it, you may not necessarily have as much as you would wish to run that industry.

True, in burning that hydrogen, you will recreate that water; but some of that hydrogen will also be lost (natural leakages).
 

Offline Batroost

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« Reply #5 on: 16/04/2007 18:20:18 »
I believe that most most Hydrogen produced at present is made from:

CH4 + 2 H2O >>> 4 H2 + CO2  i.e. it uses natural gas and steam to make Hydrogen and Carbon Dioxide.

So we need to move to a cleaner process. Electrolysis of water is the obvious choice but this will only benefit the environment if teh electricity comes from a low carbon source e.g. wind, hydro or nuclear.
 

Offline Bored chemist

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« Reply #6 on: 16/04/2007 20:10:17 »
Well, Hydrogen could be used in a more or less normal engine and it would have roughly the same efficiency as a conventional fuel like LPG, or gasoline. You might get better efficiency by using it to run fuel cells but even then you have to contend with the inefficiency of making the hydrogen in the first place.
In theory the only waste product from a hydrogen fueled car is water. In practice, if you use an ordinary engine you get dilute nitric acid because in the hot engine the nitrogen in the air reacts with oxygen and water. Of course there is the CO2 generated somewhere else making the hydrogen in the first place too.

Hydrogen is also rather difficult to store and, like other fuels, it's not something you want to spill.
Hydrogen lost to the atmosphere will almost certainly be converted back to water so that's not a major threat.
 

another_someone

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« Reply #7 on: 16/04/2007 20:26:56 »
Hydrogen lost to the atmosphere will almost certainly be converted back to water so that's not a major threat.

My concern about hydrogen lost to the atmosphere is that if it does not oxidise then it will in all likelihood be lost out into space.
 

Offline hybrid

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« Reply #8 on: 11/12/2007 10:14:47 »
OK so if i had a hydrogen generator installed in my car, how much hydrogen would it need to produce? to run it?
 

Offline Nobody's Confidant

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« Reply #9 on: 13/12/2007 17:33:36 »
I don't know who this Ben6789 guy was but I bet he was great!
 

Offline Karen W.

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« Reply #10 on: 13/12/2007 17:51:18 »
Absolutely terrific! LOL!
 

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