Most efficient way to Electrolisize water into H2 and O2

[Insane]

For PSU: You have to ground the two main power deliverance wires that plug into the mobo (they are in the biggest terminal), or the PSU will not turn on. Also, I was just preforming electro on a salt-water solution. I used a 12vDC, one amp wall outlet adapter and GRAPHITE electrodes (from an HB pencil) and it's already disintegrating. Perhaps it's not pure graphite?

[raivo]

Jdurgs calculations on NaF had presumption that you will use 1.2V. You probably will use much higher and this means you get some hydrofloric acid near positive electrode. This will corrode your device quickly (even glass) and is too dangerous chemical do deal with if you just want to make H2 and O2.

 

NaOH is surely better. I have always used stainless steel electrodes but i know of people who used common iron with satisfactory results. Graphite from pencils is of too bad quality. Its usable for very short demo not for any kind of production. Battery graphite is better but it too will disintegerate soon.

 

Make electrode surface as big as you can and place them as near to each other as possible ( you still have to be sure that H2 and O2 will never mix with each other). If you still do not get required current with 12V supply then its best to rebuild your electrolyser. Otherwise you will not cope with heating problems.

 

I suggest you to do some testing before you start to build anything. You can find answers to your questions if you just test how things are. Do some electrolysis on small flask with NaOH solution (or other electrolytes you have) also test different electrode materials and decide yourself what is most effective and reliable in your case.

 

Its good to borrow ampermeter from somewhere otherwise you do not know what current you got. PC power supplys are usually able to supply 4 ... 8 A @ 12V and 10 ... 20A @ 5V. Current will change during electrolysis at constant voltage ( usually will increase by heating ).

[Lance]

My computer psu can supply 50A on the 5V rail.

 

If you use an atx psu look here: http://xtronics.com/reference/atx_pinout.htm

 

The green and gray wire will need to be grounded(just twist the green, gray and a black wire together) as Insane already stated.

 

I should warn you however that coper electrodes are not going to last very long.

[mmalluck]

Most computer power supplies have to be tricked into running without a motherboard attached. Usually you have to tie the ground together and place a resistor across the 12v supply.

[calbiterol]

Also, carbon is by FAR anything but inert.

 

True, but inert gasses are called inert, even though they have the potential to form compounds. So, in all reality, very few, if any, elements are truly inert. I was referring to the system that gregoriev had set up, which would not react with carbon (or at least hasn't, in my experience.)

 

As for the pencil lead thing, I wasn't aware that all pencil "lead" contained clay. Even the rods in wooden pencils? I've used those, and they seem to work fine. And you don't have to get them from lantern batteries - most AA, AAA, C, and D batteries use carbon electrodes - as for other batteries, I'm not sure.

 

Also, I was just preforming electro on a salt-water solution. I used a 12vDC, one amp wall outlet adapter and GRAPHITE electrodes (from an HB pencil) and it's already disintegrating. Perhaps it's not pure graphite?

 

Yeah, apparently it's got a high clay content. The other issue might be something with the ionic NaCl - Could it be forming sodium carbonate with the carbon from the electrodes? That's soluble, and I seem to remember it being clear, so it's probably (nearly) impossible to detect without equipment.

[Gregoriev]

Okay, the dated PSUs in computer class that the teacher wil let met have all supply 24A on the 5v lines, and about 12-14A on the 12V lines.

 

Here in lies the problem, I see pleanty of 5+ and 12+ lines all over the place, and an equal number of misc. black wires entering/leaving the plugs, however according to the scematics from my A+ packets only the white wires are 5- volts...there is only ONE white wire and like 7 red ones. The same type of situatoin exists for the 12v lines.

 

How am I supposed to safely wire this baby up? Attach black wires to the negative ends, or split the white wire seven ways and attach those to the negative ends? or something i have not even thought of...

 

anyone? please?

[Lance]

You don't need the negative outputs, just the positive and ground. Also, if you see a wire thats the same color as another then they are the same output. There is only one 5+ output it's just split into multiple wires. You can use one and ignore the rest.

[raivo]

All right what Lance said. Ground is usually black (two central contacts in floppy disk connectors) +5V is usually red. +12V is usually yellow. If PSU is old enough ( from AT type computer ) then it does not need any additional connections. If it was used for Pentium motherboards it may need some more connections to switch on.

 

I have found that AT type power supplyes are most reliable for lab use. They cant be ruined by short circuits. Some newer power supplyes can be easily ruined.

[Gregoriev]

Excelent! We have like 10-15 of those old "useless" power supplies laying around and wasting space. I might be able to score a few of them no problem.

[Edward]

How do you plan on setting up the flame to burn without going out cause if the hydrogen flame goes ot and gas keeps comming then you got a prob.

[akcapr]

also you would need quite a bit of gas coming up in order to be able to light a flame

[Gregoriev]

I know I will, first of all, there will be NO WIND. Second, I will Pray that it doesn't go out.

 

Third, The flame is just a measure of how much gas the unit is putting out, just for testing really. The real awesomeness comes from collecting all that h2 and o2 in a balloon, then firing a roman candle at it in my black yard.

 

I am talking one of those three foot in diameter balloons that you hit people with...you know the kind?

[akcapr]

its gonna take a LONG time to fill one of those up. In my opinion based on my experiences it will probably take you around 80-200 hrs electrolysis to fill one. Another problem would be fighting the pressure the ballon will be exerting. That guess is very rough, but, basically u will burn alot of electrcity doing that.

[Edward]

How do you plan on inflating the baloon? Why do you want to use hydrogen in the balood? Just fill it with propane and coat it in gas (the kind you put in cars. That makes for really cool explosions. And good luck getting a rubber baloon to blow with a roman candle you need to coat it in a hily flamable substance.

[Edward]

If you want to do something dumb with fire fill milk cartons with gas and have different sised openings in them and shoot bottle rockets at them. BOOM.

[Insane]

If you want to directly fill the balloon, you'd have to do it by displacing a conductive solution. Since balloons don't like to stay inflated under pressure, it's very impractical. You could, however, fill an empty plastic 2L milk jug with Hydrogen, fit the balloons mouth over the jug's mouth and 'squeeze' the gas into the balloon. Crude, but it works.

[Gregoriev]

dear lord....i didn't think you guys would take me seriously!

 

also, i plan on trying to create "real time" electrolysis, whereby a noticable ammount of water must flow into the device/system of devices to keep it full of water. I need like a 3" flames worth of hydrogen to be produced in real time. I estimate that equates to about 25-30 identical electrolysis devices working together.

 

That;s alot of electrolysizing!

[akcapr]

probably not that many needed. id say 5-15

[jdurg]

Based upon your drawing, I do have to give you one warning, however. Make 100% ABSOLUTELY SURE that the flame doesn't backfire into your nozzle. Inside the nozzle is a perfect stoichiometric mixture of hydrogen and oxygen, and if for some reason the flame gets sucked back inside, you'll wind up with a violent explosion and shrapnel going all over the place. (You generally don't have to worry about this with typical fuels because the only thing in the fuel line is the fuel itself. The only ignition is when the fuel reacts with atmospheric oxygen. In this case, the fuel line contains both hydrogen and oxygen so the fuel can ignite within the fuel line itself and result in a nasty explosion).

[Edward]

This could be solved by having seprate lines.

[Insane]

#44: Exactly. You're going to need sufficient pressure. This sounds very cool, but very dangerous, not to mention expensive (power bills will be through the roof)

[raivo]

Separate lines makes it safe only if pressures in both lines are equal or if gases are mixed outside the burner. Most easy and safe way would be to generate just hydrogen and use it in something similar to bunsen burner.

 

Power bills would not to be that shocking. 5A of current through electrolyte should give you small stable flame. If you use 12V this needs just 60W, if 5V then 25W.

[Gregoriev]

How about I don't mix them until the moment they have to ignite? I could just have four lines come up in a cross formation, two H2 and two O2, they will discharge next to eachother and at an upwards angle. This will make the H2 and O2 mix in the air, not in some tube. (too lazy to draw a MS Pain pic. use your imaginations)

[raivo]

How about I don't mix them until the moment they have to ignite? I could just have four lines come up in a cross formation, two H2 and two O2, they will discharge next to eachother and at an upwards angle. This will make the H2 and O2 mix in the air, not in some tube. (too lazy to draw a MS Pain pic. use your imaginations)

 

It would be perfectly safe if your hydrogen is not contaminated by O2 inside of electrolyser.

[calbiterol]

MS Pain

 

How true. Photoshop is so much less... painful.