Working backwards

[BoyntonStu]

Working backwards

Proven: ~28% KOH by weight is the best electrolyte for water electrolysis.

NASA, WIKI, theory, practice, etc.

The logical starting point is with 280 gm KOH in 720 ml (gm) of distilled water to make a liter of 28% electrolyte .

We then make a cell that 'fits' the electrolyte and not the other way around.

IOW If the current is too high, we change the voltage, the area, or the spacing.

What most of us are doing seems backwards.

BoyntonStu

[Painless]

What you're saying certainly makes sense, a maximum concentration of electrolyte will maximize output. It may be difficult though to control current flow via the cell design, unless you mean to employ something like a PWM or other current limiting device? Probably easier with a dry cell to control by design perhaps?

[timetowinarace]

Depends.

If space is not a concern, you can build a unit with ideal electrolyte consentrations, plate spacing, voltages and current, ect.

But most are restricted by the size of their unit. Ideals cannot be met. Boosters are not meant to be ideal electrolysers. We can only make them as effective as possible within the size limitations.

If sacrifices must be made in active surface area due to the size of the unit, then adjustments in every other portion of the unit must be made, including electrolyte consentrations.

Whatever your most limiting factor is, whether it is size, maximum current or whatever, that is where you begin. Let's say for example size is not a limitation but you have a maximum of 30A. You need 2sq inches of active surface area for each Amp. So you need 60sq inches of active surface area per cell. Now you can continue to design the rest without limitation.(other than the natural limitations of science)

Electrolyte consentration should be the last adjustment.

[Q-Hack!]

If you use Nicholas LeBlanc's list of electrolytes and voltages required to produce Hydrogen...

Zinc Sulphate............2.35V
Cadmium Sulphate.........2.03V
Cadmium Nitrate..........1.98V
Zinc Bromide.............1.80V
Cadmium Chloride.........1.78V
Orthophosphoric acid.....1.70V
Nitric acid..............1.69V
Caustic soda.............1.69V
Caustic potash...........1.67V
Lead Nitrate.............1.52V
Hydrochloric acid........1.31V
Silver Nitrate...........0.70V

And you use the concept that Neutral plates (un-wired plates?) to reduce the voltage down. Then you get something like:

Plate Setup _________ | Volts/Cell @ 12VDC | Volts/Cell @ 13.5VDC | # Neutral Plates | # Cells | Electrolyte
+- __________________ | ___ 12 ___________ | ___ 13.5 ___________ | ___ 0 __________ | __ 1 __ |
+N- _________________ | ___ 6 ____________ | ___ 6.75 ___________ | ___ 1 __________ | __ 2 __ |
+NN- ________________ | ___ 4 ____________ | ___ 4.5 ____________ | ___ 2 __________ | __ 3 __ |
+NNN- _______________ | ___ 3 ____________ | ___ 3.38 ___________ | ___ 3 __________ | __ 4 __ |
+NNNN- ______________ | ___ 2.4 __________ | ___ 2.7 ____________ | ___ 4 __________ | __ 5 __ | Zinc Sulphate
+NNNNN- _____________ | ___ 2 ____________ | ___ 2.25 ___________ | ___ 5 __________ | __ 6 __ | Cadmium Sulphate, Cadmium Nitrate, Zinc Bromide, Cadmium Chloride
+NNNNNN- ____________ | ___ 1.71 _________ | ___ 1.93 ___________ | ___ 6 __________ | __ 7 __ | Orthophosphoric acid, Nitric acid, Sodium Hydroxide, Potassium Hydroxide
+NNNNNNN- ___________ | ___ 1.5 __________ | ___ 1.69 ___________ | ___ 7 __________ | __ 8 __ | Lead Nitrate
+NNNNNNNN- __________ | ___ 1.33 _________ | ___ 1.5 ____________ | ___ 8 __________ | __ 9 __ | Hydrochloric acid
+NNNNNNNNN- _________ | ___ 1.2 __________ | ___ 1.35 ___________ | ___ 9 __________ | __ 10 _ |
+NNNNNNNNNN- ________ | ___ 1.09 _________ | ___ 1.23 ___________ | ___ 10 _________ | __ 11 _ |
+NNNNNNNNNNN- _______ | ___ 1 ____________ | ___ 1.13 ___________ | ___ 11 _________ | __ 12 _ |
+NNNNNNNNNNNN- ______ | ___ 0.92 _________ | ___ 1.04 ___________ | ___ 12 _________ | __ 13 _ |
+NNNNNNNNNNNNNN- ____ | ___ 0.86 _________ | ___ 0.96 ___________ | ___ 13 _________ | __ 14 _ |
+NNNNNNNNNNNNNNN- ___ | ___ 0.8 __________ | ___ 0.9 ____________ | ___ 14 _________ | __ 15 _ |
+NNNNNNNNNNNNNNNN- __ | ___ 0.75 _________ | ___ 0.84 ___________ | ___ 15 _________ | __ 16 _ |
+NNNNNNNNNNNNNNNNN- _ | ___ 0.71 _________ | ___ 0.79 ___________ | ___ 16 _________ | __ 17 _ | Silver Nitrate

I am seriously thinking about trying the silver nitrate.


Hopefully the formatting is better now...

[BoyntonStu]

I thank you for your effort.

Quite a lot of work.

Keep us posted.

BoyntonStu

[Painless]

Something else to consider, I know this applies to NaOH (not sure about the other electrolytes) is that high concentrations may induce foaming. This is definitely the case in cells with electrolyte motion, i.e. a dry cell with a pump. Whilst the nasty stuff can be removed with a bubbler, the foam causes bubbles to be retained on the surface of the electrolyte and hence hinders HHO release.

Come to think of it, I had the same problem when experimenting with higher concentrations of KOH in my first real cell. There was a tendency for much larger surface bubbles in the electrolyte. This cell was an open bath with no electrolyte motion.

Something else to consider.

[countryboy18]

i havent heard of any using Hydrochloric acid why is that? great job on the inframation!!!

[ElectricSquid]

My research on using an acid as an electrolyte, or somehow being able to use copper electrodes, has brought me to this old topic.

I looked up a few of those chemicals you have there on the list/graph. From what I can tell, KOH is the first chem on on the list that we can use while still using metal electrodes. Everything listed that is better, also reacts chemically with a number of metals that we would be using to form HHO without the electricity. Or in the case of Silver Nitrate, it deposits the raw silver in a tree like crystal structure on the electrode.

Below is a little info and a few video links I've gathered during my search through the list... enjoy, a few of them are pretty neat, others are downright explosive...



Silver Nitrate
chemical formula: AgNO3

A popular demonstration using Silver Nitrate is the production of pure Silver metal. Clean Copper wire or rod suspended in a Silver Nitrate solution will produce a gleaming Silver tree if allowed to stand undisturbed.

link to this experiment...
http://www.unitednuclear.com/silvertree.htm

A solution of Silver Nitrate mixed with a solution of Sodium Chloride (table salt) will produce a precipitate of Silver Chloride, which turns purple on exposure to light.

Contact with Magnesium powder should be avoided. Magnesium & Silver Nitrate Mixtures can explosively ignite without warning or on contact with the slightest amount of moisture.

Here's a great video of that reaction :D
http://www.youtube.com/watch?v=qMG53X2QmAQ

Caution: Silver Nitrate is a powerful & corrosive oxidizer. Use normal safety precautions (wear a filter mask/respirator and gloves) when working with Silver Nitrate.

Here's the link where I got most of that text info. Just travel down the page to find and buy some if you like :cool:
http://unitednuclear.com/chem.htm




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[ElectricSquid]

Onward to ...

Hydrochloric Acid
chemical formula: HCL

Just do a video search for "hydrochloric acid and" and you'll see why we should probably never think about putting a metal electrode in it :eek:

http://video.google.com/videosearch?q=hydrochloric+acid+and+&emb=0#

BUT... :cool:
If you're going for a non-electric, chemical reaction style hydrogen generator, then hydrochloric acid is probably the choice for you, since it releases hydrogen like gang-busters when it's given some metal to chew on :P.

As far as I've read and heard, there's some high dollar research & development going on with the chemical reaction between hydrochloric acid and aluminum in order to produce high amounts of hydrogen gas in a very short amount of time. The uses for controlling that reaction are too many to list.

Here's a video showing the hydrochloric acid and aluminum reaction, better known as the...
Hydrochloric Acid Bomb :eek:
http://www.youtube.com/watch?v=fUlSG7zQ1j8



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[ElectricSquid]

Lead Nitrate
chemical formula: Pb(NO3)2

I didn't bother researching this one since I've eaten enough lead paint chips in my youth to know that I've had my fill of lead for one lifetime. Due to the lead, it's not a good idea to use this stuff. You've been warned, my job is done here....


Caustic potash
(Potassium Hydroxide)
chemical formula: KOH

We all know what this one is, do I need to say more?



Caustic soda
(Sodium Hydroxide)
chemical formula: NaOH

Same with this chemical, we all know what this one is...



Nitric acid
chemical formula: HNO3

Add Copper to Nitric Acid and it gives off Nitric Oxide :) Interesting...
What's even MORE interesting is what exactly Nitric Oxide is used for, or should I say... "in"
Viagra, Levitra, Cialis, do any of those drugs ring a bell? They all contain Nitric Oxide as the active ingredient.

http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/N/NO.html

Unfortunately, it seems to be a little expensive for our needs. 500 ml of a 70% solution will run you around $50



Orthophosphoric Acid
(Phosphoric Acid, kind-of, but maybe not, see below)
chemical formula: H3O4P

Check out the wiki on this stuff. Orthophosphoric Acid covers a wide range of chemicals that are very similar and highly chemically reactive, giving off a hydrogen atom in each of it's stages. Phosphoric Acid only covers one of it's stages.

It seems like an interesting chemical to work with, but highly complex...

http://en.wikipedia.org/wiki/Phosphoric_acid



... and that's about it for me for one night.
See ya tomorrow :cool:


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