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Hydrogen Production for running gas engines

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Bjørn

Thu Apr 12 2007, 02:02AM

Registered Member #27 Joined: Fri Feb 03 2006, 02:20AM
Location: Hyperborea
Posts: 2058

Don't forget to think about safety. The energy required to ignite hydrogen is something like 20 uJ so it ignites very easily. The diffusion coefficient is large so it mixes fast with air and it is explosive at a wide range of mixture ratios.

If you are collecting enough hydrogen to run an engine you need to be careful.

Coronafix

Thu Apr 12 2007, 03:20AM

Registered Member #160 Joined: Mon Feb 13 2006, 02:07AM
Location: Melbourne, Australia
Posts: 938

I have heard that by pulsing the electrodes at about 42.8kHz, you use much less energy to seperate
the water into hydrogen and oxygen.
The theory is that it jiggles the water at its resonant frequency or one of its harmonics,
therefore not needing the brute force of a lot of current.
Has anyone tried this yet? I have been meaning to for some time, should be easy to setup.

Bjørn

Thu Apr 12 2007, 04:16AM

Registered Member #27 Joined: Fri Feb 03 2006, 02:20AM
Location: Hyperborea
Posts: 2058

Water molecules are extremely small. It is hard to imagine any resonance in the kHz range.

Have a look at this:

My speculation is that 42.8kHz is the resonant frequency of someones ultrasound tranducer in water that caused the release dissolved air from the water that was interpreted as hydrogen by someone that did not know what they were doing.

Coronafix

Thu Apr 12 2007, 06:11AM

Registered Member #160 Joined: Mon Feb 13 2006, 02:07AM
Location: Melbourne, Australia
Posts: 938

Seems strange that a kHz frequency could affect it then, but it was definately an efficiency thing
rather than trapped air release.
There are several patents issued on it as well, to create parahydrogen.

Myke

Thu Apr 12 2007, 06:16AM

Registered Member #540 Joined: Mon Feb 19 2007, 07:49PM
Location: MIT
Posts: 969

The resonant frequency of water is around the frequency that microwave ovens operate.

AndrewM

Thu Apr 12 2007, 06:29AM

Registered Member #49 Joined: Thu Feb 09 2006, 04:05AM
Location: Bigass Pile of Penguins
Posts: 362

Myke wrote ...

The resonant frequency of water is around the frequency that microwave ovens operate.

I seem to recall that this was discussed here at length and was debunked as a myth.

Bored Chemist

Thu Apr 12 2007, 04:54PM

Registered Member #193 Joined: Fri Feb 17 2006, 07:04AM
Location: sheffield
Posts: 1022

"Also, potassium chlorise is 33% or so of Losalt (tm) so this should help."
I don't see chlorine production (as a by-product) helping a lot. Washing soda makes nearly as good an electrolyte as potassium hydroxide. Sodium hydroxide is effective, cheap and easy to get. The efficiency gain by using KOH isn't that great.

That stuff about parahydrogen and ultrasonic resonances of water is nonsense.
The microwave oven excites rotational resonances. The vibrations are in the infra red.
On the safety side, when our lab was setting up hydrogen generators we only bothered to look at the risk of a leak. It was presumed that, if there was a leak, the stuff would ignite. Storing hydrogen isn't something I'd recommend as an amateur project.

Coronafix

Thu Apr 12 2007, 11:11PM

Registered Member #160 Joined: Mon Feb 13 2006, 02:07AM
Location: Melbourne, Australia
Posts: 938

Bored Chemist wrote ...

That stuff about parahydrogen and ultrasonic resonances of water is nonsense.

So you've tried it then? The patents talked about using the reaction chamber
as a capacitor in a resonant circuit, so a coil is also involved.
Is this what you used?

Marko

Fri Apr 13 2007, 12:31PM

Registered Member #89 Joined: Thu Feb 09 2006, 02:40PM
Location: Zadar, Croatia
Posts: 3145

I have found that aluminum foil and drain cleaner (lye) works great/fast

I don't know if you guys tought anbout that, but if hydrognen produced such way is used to run an engine, acidic vapor will start destroying the engine rapidly. It would need to be neutralised somehow before that.

I used to put really small amounts of zinc in muratic acid to get the zinc chloride, in a small dish on my window letting the hydrogen escape... still, enough of nasty acidic vapor ended in my room to make me itchy and my eyes red.
I did that only outside after that!

If you thorw a large bunch of aluminium foil into acid and it starts to boil, youa re asking for trouble!

Except aluminium and zinc, steel wool also works and reaction is somewhat less violent.
But, all those ways are still much more expensive on long run than electrolysis alone...

Chris

Fri Apr 13 2007, 02:23PM

Registered Member #8 Joined: Thu Feb 02 2006, 04:34AM
Location: Harlowton, MT, United States
Posts: 214

I'm assuming the acidic vapors would be recondensed, which would be much easier if you used sulfuric instead of hydrochloric acid. Still, perhaps if I restate another way, it will be easier to see the inherent fallacy with that method:

To produce an amount of hydrogen equivalent in weight to a gallon of gasoline, it would require 114kg of HCl gas (82 gallons of muriatic acid) and 28kg (62.5lbs) of aluminum. To make an amount equivalent in energy to a gallon of gasoline would require only 30 gallons of muriatic acid and 23lbs of aluminum though, but good luck getting that to fit on your lawnmower.

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