CR4 - The Engineer's Place for News and Discussion ®


Previous in Forum: Air Pollution Control - Bag Filters   Next in Forum: Store That Solar Energy
Close
Close
Close
9 comments
Power-User

Join Date: Jan 2011
Location: Scotland
Posts: 361

Salt in HHO Generator

03/25/2014 7:24 AM

The first hydrogen generator I ever built consisted of 2 aluminium tubes inside each other. I was using tap water mixed with salt as the electrolyte. I connected the generator to a small metal tube with a 2mm opening in it which I was using as the burner, I lit the gas and it and it was able to burn a tiny flame as if there was no oxygen being produced. I just couldn't get a flashback at all. When I changed the electrolyte to weak sulfuric acid and lit the gas, it would flash back into my small bubbler immediately leading me to believe that oxygen was now being produced. The salt electrolyte resulted in white paste like stuff building up on the tubes and a smell of chlorine when I opened the generator to clean it.

I have since purchased a much larger hho generator with 316l stainless steel plates. I did a test run with weak sulfuric acid. Much weaker than that in a battery. The plates and electrolyte went green and as expected and lighting the gas resulted in an instant flashback.

I am interested in storing the gas at low pressure but certainly not if it has oxygen mixed in with it. Where could the oxygen be going when I used salt water?

Register to Reply
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.

Comments rated to be "almost" Good Answers:

Check out these comments that don't yet have enough votes to be "official" good answers and, if you agree with them, rate them!
Guru
New Zealand - Member - Kiwi Popular Science - Weaponology - New Member Engineering Fields - Power Engineering - New Member Engineering Fields - Electrical Engineering - New Member

Join Date: Sep 2006
Location: Auckland, New Zealand
Posts: 8166
Good Answers: 329
#1

Re: Salt in HHO Generator

03/25/2014 2:57 PM

......hho generator with 316l stainless steel plates........

I am interested in storing the gas at low pressure but certainly not if it has oxygen mixed in with it.......

HHO generators with stainless steel electrodes are hopelessly inefficient at generating hydrogen gas. If you really want Hydrogen gas for a specific application then please consider obtaining it other ways such as by chemical reaction or just purchasing bottles of it. Even taking remote are transport costs into account you will get far more pure Hydrogen gas for your money.

See numerous threads on CR4 regarding HHO generators, etc.

Kudos by the way in calling yourself "hydrogenhead" but apparently (after a quick site search) refraining from asking HHO questions on CR4.

__________________
jack of all trades
Register to Reply
Power-User

Join Date: Jan 2011
Location: Scotland
Posts: 361
#2
In reply to #1

Re: Salt in HHO Generator

03/25/2014 5:04 PM

So 316l is great for HHO but not hydrogen? Every other site says that stainless steel or titanium is the best thing to use.

Register to Reply
Guru
New Zealand - Member - Kiwi Popular Science - Weaponology - New Member Engineering Fields - Power Engineering - New Member Engineering Fields - Electrical Engineering - New Member

Join Date: Sep 2006
Location: Auckland, New Zealand
Posts: 8166
Good Answers: 329
#3
In reply to #2

Re: Salt in HHO Generator

03/25/2014 6:08 PM

From my research into the subject over the years, Stainless steel electrodes are generally considered the best and cheapest that will actually work, the problem is that the efficiency is hopelessly low. The best is actually Platinum, but obviously this is far more expensive and hence almost never used and generally totally ignored by the backyard hydrogen electrolysis or HHO experimenters.

What's the actual application? I am really hoping you just want an easy Hydrogen source (for something) rather than trying to convert electricity to Hydrogen then using the Hydrogen to produce electricity, heat, etc rather than just using the electricity to avoid cascading system losses. Or adding it to an internal combustion engine.

__________________
jack of all trades
Register to Reply
Power-User

Join Date: Jan 2011
Location: Scotland
Posts: 361
#5
In reply to #3

Re: Salt in HHO Generator

03/26/2014 3:14 AM

I am currently using it for metal work but if I could store hydrogen on it's own, I would use my solar panels to generate it, as hydrogen storage at low pressure such as 50 psi stored in a large tank seems to be a more cost effective energy source for cooking with and melting metal than using the electricity stored in expensive batteries to heat metal. I don't believe that an HHO system will work in a car at all unless you are providing the hho from hydrogen and oxygen storage tanks or generating it on demand using a lithium ion battery to power the HHO generator.

Register to Reply Off Topic (Score 5)
Guru
New Zealand - Member - Kiwi Popular Science - Weaponology - New Member Engineering Fields - Power Engineering - New Member Engineering Fields - Electrical Engineering - New Member

Join Date: Sep 2006
Location: Auckland, New Zealand
Posts: 8166
Good Answers: 329
#6
In reply to #5

Re: Salt in HHO Generator

03/26/2014 2:30 PM

I would strongly advise you to look into actually buying natural gas (or similar) from a local supplier and using your existing solar supply for something else. Even if you are in a remote area you will very likely find (in my personal opinion) that this is the cheaper (and safer) option.

Yes transport costs will be high for remote area delivery but bottled gas is cheap, and you get a large amount of gas for your money that could last you many months (or longer). This is what I would do if I were in your position. Heck, for really remote areas you could buy smaller bottles and pick up and deliver them yourself if necessary.

__________________
jack of all trades
Register to Reply
Guru

Join Date: Oct 2008
Posts: 39041
Good Answers: 1533
#4

Re: Salt in HHO Generator

03/25/2014 9:57 PM

Suggest you Google HHO.

You will find: Oxyhydrogen is a mixture of hydrogen (H2) and oxygen (O2) gases.

Oxyhydrogen - Wikipedia, the free encyclopedia

Register to Reply
Guru

Join Date: Apr 2011
Posts: 5909
Good Answers: 211
#7

Re: Salt in HHO Generator

03/30/2014 12:54 AM

"...Where could the oxygen be going when I used salt water?..."

.

The problem is that it isn't going anywhere. When you use table salt as the electrolyte, chlorine (as your nose informed you) and hydrogen gas as well as sodium hydroxide will result from the electrolysis.

.

Tap water can have significant amounts of chlorides and/or chloramines, fluorides, and other chemicals that might contribute to accelerated degradation of your electrodes. Deionized and or distilled water would be a better choice.

.

For electrolysis yielding hydrogen gas and oxygen gas, there are a number of electrolytes that can work. The material used for the cathode and the material used for the anode should ideally be decided in conjunction with the choice of electrolyte.

__________________
Eternal vigilance is the price of knowledge. - George Santayana
Register to Reply Score 1 for Good Answer
Power-User

Join Date: Jan 2011
Location: Scotland
Posts: 361
#8
In reply to #7

Re: Salt in HHO Generator

03/30/2014 6:22 AM

I just found out that hydrogen and chlorine mixture is just as dangerous as HHO. It will not flash back down the tube when you light it, and can be burned through quite a large opening. The problem is, if exposed to UV light it will explode quite violently. The only way for me to get storeable hydrogen is to use a separator cell it would seem.

Register to Reply
Guru

Join Date: Apr 2011
Posts: 5909
Good Answers: 211
#9
In reply to #8

Re: Salt in HHO Generator

03/30/2014 2:16 PM

In some aspects, chlorine is more dangerous.

.

I'm not sure exactly what specifically you have in mind when you say 'separator cell', or if you just mean any technology that will lead to the two gasses being segregated.

.

There are a number of ways to separate hydrogen and oxygen, with varying degrees of effectiveness and varying degrees of expense.

.

One simple place to begin is designing the system such that the gas bubbles developed at the cathode and the gas bubbles developed at the anode ascend to two different spaces. . This can be accomplished fairly inexpensively, and if some sort of permeable divider is used, the electrodes don't have to be excessively distant either.

.

There are a number of ways to separate the gasses from a mixture. Membranes, pressure swings in a zeolite filled chamber, using something like liquid nitrogen to condense the O2 (there are a number of special hazards with that approach), forming metal hydrides,..... techniques abound. I remember some people were using high voltage to store hydrogen in a solid palladium bar, though I don't know much about that at all. The point is, there are numerous ways to approach that problem.

.

If you are going to segregate your gasses (I assume for storage) high pressure electrolysis is worth some consideration.

__________________
Eternal vigilance is the price of knowledge. - George Santayana
Register to Reply
Register to Reply 9 comments
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.

Comments rated to be "almost" Good Answers:

Check out these comments that don't yet have enough votes to be "official" good answers and, if you agree with them, rate them!
Copy to Clipboard

Users who posted comments:

hydrogenhead (3); jack of all trades (3); lyn (1); truth is not a compromise (2)

Previous in Forum: Air Pollution Control - Bag Filters   Next in Forum: Store That Solar Energy

Advertisement