Hydrogen electrolysis

[yourgreendream]

I am currently looking at catching the overflow from my batteries (when they are charged divert the power) into an electrolysis device to generate hydrogen to power my BBQ. I have been looking around for a while and the only things I can see a either tiny or very large system that produce very good quality hydrogen. So I have come up with a bit of a design and before I put in alot of effort into building it I was just after some criticism and suggestions to make it as good as I can before I start.

So if you have any experience or are bored, I would love any suggestions before I start. It's all spelled out here -> My Hydrogen Electrolysis Design.

I would love any feedback.

Thanks.

DANGEROUS activity

which is contrary to our policies.

[scottsAI]

Hello yourgreendream,

Very interesting idea. And dangerous.

How are you going to pump it into a storage tank?

What pressure?

What tank?

Hydrogen production is done at pressure, pump in the water. Get rid of the oxygen.

How about put an electric heater in the grill, may be easier!

Have fun,

Scott.

[WXYZCIENCE]

I tried something similar back a few years, in high school science club. When I ignited the hydrogen, it exploded and got me kicked out of the club. I think some O2 got mixed in my hydrogen collection flask. Very dangerous! Joe.

[yourgreendream]

I was going to get a large collection tank and leave it in there, just at the presure of the water in the tank behind it.

Does it need to be done at high pressure? or is that just move space effecient for a system to store hydrogen.

I just want to store enough to keep a bbq going for half an hour or so once a month.

[stop4stuff]

I've had a play with electrolysers, see reply #22 here

There's a few things about your design that need some thought;

Hydrogen storage is notoriusly difficult - hydogen can escape from just about any container. Hydrogen will also break down most plastics.

As already mentioned, the use of a flashback arrester is essential, and I would also use a water bubbler to keeep the gas 'damp' preventing static build up.

The amount of gas produced and current drawn depends the resistance of the elecrolyte, the distance between the anode & cathode and the surface area of the anode & cathode.

paul

[yourgreendream]

Can you explain static build up, what is it? Sparks within the tank? Generated as the gas moves through the pipes?

[thunderhead]

As a fluid moves around, electrons get knocked off some molecules and stick to others.  The motion of the fluid separates these charges, storing mechanical energy in the form of a voltage.  

If the fluid is non-conductive (like dry hydrogen) the charge can build up until there is a spark.  The same mechanism creates sparks -- lightning -- in rainclouds.

Oh, and whenever I've experimented with electrolysis, I've used graphite rods out of ordinary zinc-carbon torch (flashlight) batteries.  They're cheap, and they're to all intents and purposes non-reactive.

But I've not experimented with hydrogen storage, because I've never seen a way to do it safely.

[David HK]

It seems a bit unfair to submit a post asking people on this site for comments about the generation and storage of hydrogen gas. I doubt very much if any regular commentators and visitors to this website are qualified engineers who routinely work with the production of hydrogen on a daily basis.

Hydrogen is dangerous stuff!

Surely you could find an alternative which will not blow you or some other poor unfortunate to pieces from poor engineering or simply not knowing what you are doing.

Dave HK

[powerbuoy]

One question I have is what would you do with large amounts of low pressure Hydrogen?

Powerbuoy

[electrondady1]

the electrodes will need changing from time to time . with them being on the bottom, i would think it could be kind of messy and difficult to seal up?

[oztules]

Well you could run a petrol generator with a little bit of work and a low pressure converter, or you can use it for anything you can use natural gas for. (low pressure already may need to adjust air/fuel ratio), gas lighting, etc etc.

You can do what William Gove did in the late 19th century...make electricity..(using the electrolyser for a poor mans fuel cell)

Here: http://www.ahanw.org/library/remotepdf.php?pdfurl=H2HOME%7e1.PDF

is a good article for reading from Homepower feb/march 1994 before you start. It discusses the use of electrolysers, and also makes mention that they produced 16v@10amps for a couple of hours (I assume before the electrodes used up their supply of bubbles on their surfaces.)  This aspect requires further research, and just may provide some use for the dump power from oversize mills.

It also discusses the electrolyte you will  probably be using, and its maintenance, as well as the use of arresters and bubblers and catylitic absorbers (to remove all traces of oxygen from the hydrogen gas stream)

It also gives graphs for the impurity risks as the current slows up, which will be useful to keep purity.

A worthwile experiment, and one I shall play with at a later date.

.............oztules