Building an Electrolyzer

[Dr Dimento]

Alright, i've been reading this forum for about a week now to avoid the whole "gawd this is the 10324234th time this has been asked" situation most people tend to cause.

First of all, please forgive me, as i have not been through any formal college chemistry classes. I'm merely someone interested with hydrogen from water experimentation.

Anyway, i'm going to try to build an electrolyzer from scratch, possibly 5 or 6 cells. Looking thru (every single) picture on the website, and the associated stories and reading most of the forum post pertaining to it....this is what i've jotted down.

1) Voltage does not matter as long as it's above 1.2v
2) Gas production goes up with amps
3) Use DC
4) NaOH for the electrolyte (good, safe, no byproducts)
5) Sprinkle aluminum dust in the electrolyte/water? (not sure about this one, from a post that doesn't provide sufficient backround information)
6) Use a bubbler so i don't die and stuff.......

Please, any tips on building a better electrolyzer would be appreciated. Also, a shopping list for chemicals (household names anyone?)
Is 316 stainless the best material for the plates/electrodes?

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Now from two interesting posts on this forum i gather that a simple electrolyzer is not nearly as efficient as what AlaskaStar/thrival came up with in that 7 page post. I get the idea, but i would appreciate if someone would walk me thru this in layman's terms....if no one will i understand, but it would be much appreciated.

It also seems less efficient than loster's "aluminum can/alumnimum & NaOH" method. I still don't under stand this method either, anyone care to explain what's going on? Is he just creating a simple electrolyzer and putting small pieces of aluminum in it? This increases Hydrogen/oxygen production how?

Also (and forgive me if it's a stupid question). If i wanted to keep the hydrogen and oxygen gas separated, could i just put a conductive metal plate in the center of the cell and a gas escape tube on each side of the cell, - side for H2 and + side for O? Would electrolysis still occur? Constructing a membrane seems to be a good deal of work...however if the metal plate thing don't work i have plenty of goretex, but that method doesn't seem very good either.


Thanks in advance folks, much appreciated.

[Loster]

Dimento :

Hi !

Well if you want to test electrolyzer designs and fiddle with it during some months until you get a tiny amount of H2, go with the electrical one .. It's the way to go in my opinion, because the probability that there is a method to increase the efficiency is high, but you have to find the caracteristics of the driving circuit that will provide the best gas output ..

Some here pretend to have done it, Bob Royce, AlaskaStar .. It's not clear what is the role of Thrival in all that, I think he's just fiddling with this.. And surely, the ones that knows how to do it don't want to give us the opportunity to test their work . . Go figure ! ..

And there is the method that really works but that consume Aluminum and tiny amounts of NaOH ..

I've done it and the method generates HUGE amount of H2 !! ..
I call it the chemicalyzer ..

You don't need Power Input .. You just have to design a leak-free unit that
is very sturdy with a mecanism to input Aluminum and Water ..
You need to keep separated the trash that the reaction will create from the NaOH/Water solution ..

The NaOH/Water will "eat" the Oxide Layer that creates on the Aluminum so AL will be exposed to Water and it will reform it's oxide layer by taking O from Water and letting out H2 from water . .

It is simple .. You mix NaOH and Water together, in a +20% concentration (- That's what I have done, you'll have to test -) and you drop Aluminum flakes or any Aluminum in the solution ..

I've used Aluminum Cans and Aluminum Foil and some Aluminum scrap, everything worked .. Than, the reaction takes some time to start, maybe 1-2 minutes to get a good amount of gas .. I think it's because the reaction is best at a certain temperature .. The reaction will cause heat in the unit, so you'll need to find a way to get the best Temperature Ratio ..

And if you put some of these units together, you have a HUGE amount of H2 ..

Oh, and the rate of consumption of AL is NOT that much ! .. I have a unit that worked for a week and 1 pound of AL wasn't all consumed .. Well it didn't work at full gas output, because it consumed some NaOH ..

Anyways, it takes about 6 KWh of power to generate 1 pound of Al (- I think it was 1 pound, have to verify -) .. So you might get some stored power out of this . .


Now the problem comes with implementation .. You'll have to find a way to regulate gas output before putting it in a Carb ..

Regulating the AL drop might do it .. but I would go for storing some amount of surplus H2 and injecting in a carb . .

[Bob Boyce]

Dr Dimento

It looks like you have the basics covered, except for the aluminum dust part.

Electrolysis does not use the oxidation of aluminum to generate hydrogen. That is a different technique, the one that Loster is experimenting with. While I may not agree with his methods of verbally attacking other experimenters here, he is entitled to his opinion.

As far as seperation of the gases, by adding a metal plate, you will only cause formation of opposite gases on the surfaces of that plate, so it would not provide the gas isolation you seek. You would need to use a nonconductive barrier that is permeable to the electrochemical reaction below the liquid while being non-permeable to the gases above. Please keep in mind that the farther apart your plates are, the higher your IR losses are. High IR losses are a killer of efficiency.

You may be better off obtaining some material to filter the gases after production. I understand that there are several to choose from, but they are beyond the scope of my experience. I will have to defer that subject to someone else with more experience in that matter.

Bob

[Bill]

DR Demento, email me your phone number and best time to call, I will be glad to walk you through the whole process. Hey Bob Boyce, how the hell are you Sir?

[johnh]

Im with you on this Loster

While scrap aluminium is fairly cheap and the electrolyser designs are still relatively inefficient, aluminium chemical reactions seem to offer the best prospect of running a car on hydrogen totally in the short term.

Also because the hydrogen is pretty pure it makes storing a small amount of gas a lot less dangerous than Hyd/Ox mix.

from http://www.chemlink.com.au/alumina.htm your electric consumption for aluminium production is right - they say 6.35kWh /Lb.

Like you I haven't managed to completely to stop some usage of NaOH in the process but I think I am getting closer by washing the Alumina with the electrolyte - this seems to convert any sodium compounds back to NaOH. I am pumping the electrolyte through a ceramic filter to get the alumina and paint and other crap out of the reactor but its not working very well at the moment.

This is what I am basing my design on
http://www.waterstof.org/20030725EHECO1-7.pdf
Its fairly old and I haven't found any updates on the idea. It looks like it was maybe a uni. thesis or something that never went anywhere but interesting non the less.

You will notice in this design they did not recognise that the NaOH was a catalyst they are talking of electrolysing the sodium compounds back to NaOH. Well at least thats how I read it.

There is a lot of information in the waterstof site but not all has been translated and I'm strictly a one language guy.
All the best
JohnH

[Dr Dimento]

Hey thanks for the info guys.

I'll go ahead and try both ways, i have nothing but time.

Bill, i'll take you up on your offer, but give me a couple months. I'm in the military, stationed at Incirlik AB, Turkey. I'm sure the phone call would cost a TON. I get re-stationed in Florida in 2 months, so until then i'm just working on a design for my electrolyzer.

From the information i got in this post....i think i'm going to make it somewhat like 2 heatsinks, with one's fins between the others, but never touching. This should maximise surface area and reduce resistance, hopefully making it more efficient. I'll run a bubbler after it, with a balloon on top....designating a point somewhere above the balloon to measure to. This way i can accurately measure my production rate by how much time it takes to make the balloon inflate to reach that point.

Keeping the bubbler/balloon in the same spot, i'll then try loster's method with the AL and measure that as well.

I'm willing to blow about $1000 on my experiments total once i get to my next base. I've already budgeted $500 for a 120watt solar cell so i can honestly claim whatever i power with the solar/hydrogen is "free power". My main purpose for the solar is to power the electrolyzer.

Anyway, thanks for the info!

[Dr Dimento]

FYI for everyone. After all my searching all night, the cheapest source for a decent high amperage/low voltage power supply is actually my computer's PSU and use a *short* so i can use it without a motherboard.

This is great because i have about 5 spare PSU's (im a geek). I can also do a bit of testing as well due to the various amperages on each rail, for instance they are as follows:

12V: 18a
5.0V: 40a
3.3V: 30a

I'll probably just use the 3.3v rail with a single cell or perhaps two cells.

1.65v 15amp 2 cell setup seems like the most efficient setup with this powersupply, and i should only draw about 99 watts if my math serves me right.

Any input? Would this even work, or does anyone have a better idea for a power supply?

[Bob Boyce]

Others have used computer power supplies and had moderate success. Be sure to allow plenty of leeway on current draw. They do not work for long if you load them anywhere near maximum ratings for an extended period of time. The advantages are they are fairly efficient, common, inexpensive, and easy to replace when they do fail.

Bob

[Dr Dimento]

btw, loster........would nitric acid help dissolve the leftover aluminum oxide in the water? I've just been doing a bit of research and ran across something that said it would. Not sure how that would react with the NaOH though, and it wouldn't clean out the paint and crap either.

[Chris]

[Loster]

[Dr Dimento]

[Loster]

[JaEnergy]

[johnh]