Generate hydrogen for filling SOME balloons? (electrolysis)

[()blivion]

Hi, I got something kinda neat at the thrift store for one whole entire dollar today.

It's a Toytronix "BalloonCraft 2000" lighter than air RC aircraft. Which you can read all about HERE.

Being a lighter than air craft, it requires a gas lighter than air to fill it's balloon. Now I could go to the local store and look odd as hell trying to talk the manager into letting me steal some of there display balloon Helium. Or I could go and buy/rent an overly expensive helium canister for this 1$ toy. But being the (almost) 30 year old kid that I am, and having no concern for my eyebrows, I had considered

"Whats the next best thing to helium?"

So, does anyone here know a decent way to generate enough hydrogen to fill an ~11 inch balloon easily? I am of course looking for a way to do it with electrolysis. And it must not contain ANY oxygen, like the browns gas method generates. This would pose both a loss in performance, and an explosion hazard. Which I would like to avoid if possible. If not... Oh well.

(Note: I could Google it up, but I think it's funner to turn this into a discussion. I'm not trying to be lazy... probably)

 

[Jaguarjoe]

Mix steam with natural gas, the H2 will crack off. Filter it through a multibed PSA unit, pump it up and fill your baloon (many, many baloons!)
Easier route- travel to Ashtabula, Ohio, look for the Praxair air separation plants (tall columns, you can't miss'em). Ask politely and your baloon will be filled. IIRC, Fontana, CA can do it too.

 

[KJ6EAD]

Lye solution and aluminum.

Aluminum + Sodium Hydroxide + Water --> Sodium Aluminate + Hydrogen

2Al(s) + 2NaOH(aq) + 2H2O(l) --> 2NaAlO2(s) + 3H2(g)

https://www.youtube.com/watch?v=zdFor-azNk8&feature=youtube_gdata_player

 

[ChrisP58]

Electrolysis will work to separate water into it's component gasses. Just space your electrodes far enough apart to keep the hydrogen and oxygen separate.

The problem you are going to have will be in getting the hydrogen pressurized to stretch the balloon.

Maybe some way of feeding the input port of a bicycle pump only with the captured hydrogen?

 

[()blivion]

Mix steam with natural gas, the H2 will crack off. Filter it through a multibed PSA unit, pump it up and fill your baloon (many, many baloons!)
Easier route- travel to Ashtabula, Ohio, look for the Praxair air separation plants (tall columns, you can't miss'em). Ask politely and your baloon will be filled. IIRC, Fontana, CA can do it too.

lolz, that's FAR FAR to much out of my way just to fill 2-5 eleven inch balloons. But thanks for info. If I ever need MASSIVE amounts of hydrogen... I'll know where to go.

Lye solution and aluminum.

Honestly, your right in the sense that I really should just break down and use chemistry on this one, more efficient/effective. I was thinking of acids and light mass metals though. When I made the post, I was hoping for "a system" that could be left in place, requiring only water and electricity, and that would make enough hydrogen to 1 cubic foot in an hour or so. And electrolysis fits that idea nicely.

Electrolysis will work to separate water into it's component gasses. Just space your electrodes far enough apart to keep the hydrogen and oxygen separate. The problem you are going to have will be in getting the hydrogen pressurized to stretch the balloon. Maybe some way of feeding the input port of a bicycle pump only with the captured hydrogen?

Electrolysis is what I was looking for, I just need to know the maths (estimations) that tell me how many Volt's/Amps I need to make 1 cubic foot of hydrogen per hour. Also need to figure the optimum apparatus structure. Separating the electrodes and lowering the resistance enough to pass respectable currents are counter opposing optimizations. As far as pressure, you completely got me there, I didn't even think of that. I do have pumps and things I could use to do that. the problem is leakiness. I would have to build some kind of internally enclosed pump system, like how a refrigerator is done... or something.

Now, correct me if I'm wrong, but making the gas does actually generate considerable pressure. It's just I can't trap that pressure and force it into a particular direction easily. What I need is a way to make something like a passive conductive wall in between the two main electrodes. Something that will not create gasses on it's surfaces, but will pass the current between the layers of electrolyte. I'm pretty sure that's impossible though, as the ions are what transport the charge, and also how the gas is made.

Any ideas?

 

[colin55]

This is the piece of equipment you need:
**broken link removed**

**broken link removed**

Seal off the tube so the gas will enter a balloon.
Keep letting out the oxygen.

 

[dougy83]

Electrolysis is what I was looking for, I just need to know the maths (estimations) that tell me how many Volt's/Amps I need to make 1 cubic foot of hydrogen per hour. Also need to figure the optimum apparatus structure. Separating the electrodes and lowering the resistance enough to pass respectable currents are counter opposing optimizations. As far as pressure, you completely got me there, I didn't even think of that. I do have pumps and things I could use to do that. the problem is leakiness. I would have to build some kind of internally enclosed pump system, like how a refrigerator is done... or something.

Thinking back to high-school chemistry.. 1 mole of gas is 24.5L @ STL (25^C, 1 atm), and you'll need 1 mole of H+ ions to get 0.5 mole of H2 gas. A 11" spherical balloon holds ~11.5L, which is roughly that half mole.

From wikipedia, "The magnitude of the electrical charge of one mole of elementary charges (approximately 6.022×1023, or Avogadro's number) is known as a faraday unit of charge (closely related to the Faraday constant). One faraday is equal to 96485 coulombs."

So you'll need roughly that many coulombs to fill each balloon (maybe a bit more due to the balloon pressure). 96K Coulombs is around 27 A.Hrs... so you can fill a balloon an hour at 27A.

Now, correct me if I'm wrong, but making the gas does actually generate considerable pressure. It's just I can't trap that pressure and force it into a particular direction easily. What I need is a way to make something like a passive conductive wall in between the two main electrodes. Something that will not create gasses on it's surfaces, but will pass the current between the layers of electrolyte. I'm pretty sure that's impossible though, as the ions are what transport the charge, and also how the gas is made.

Maybe a salt-bridge made out of porous ceramic (e.g. a porous ceramic bottle to hold the hydrogen? It might be a bit difficult to get enough current through it depending on the bottle.

 

[Boncuk]

Just remember the Lakehurst disaster when a zeppelin (LZ 129 Hindenburg) blew up in a huge ball of fire upon landing.

Better use Helium. It has about the same specific weight as hydrogen, but is 100% safe!

Boncuk

 

[colin55]

Helium is only half as efficient as Hydrogen.

 

[dougy83]

Better use Helium. It has about the same specific weight as hydrogen, but is 100% safe!

Firstly, that's boring! And secondly, isn't hydrogen (atomic weight 1, gas formH2 for 2 molec. weight) half the density of helium (atomic/molec. weight 4).

AFAIK helium is much more difficult to make at home, unless you happen to have some radioactive material.

 

[jpanhalt]

Helium is only half as efficient as Hydrogen.

Not quite sure what you mean by "efficiency." It is a common misconception that helium will lift only half as much as hydrogen. As alluded to by Buncuk, that is not the case.

The average weight of air is about 29 g /22.4 L at 0°C (24.5L @25°, standard pressure). For the sake of discussion call that a "mole" of air. The mass of helium is 4 g/mole and hydrogen (H2) is 2 g/mole. Thus at 0°C and standard pressure in air, the buoyancy of 1 mole of helium is 25 g and 1 mole of hydrogen is 27g. Helium can therefore lift 93% as much as the same volume of hydrogen will lift. (deleted "mass," as what I really meant was mole)

@()blivion
As for capturing and pressurizing the hydrogen, you can capture it in a collapsed clothing bag or trash (no holes of course). Then close the end and insert a tube to your balloon. Roll the bag up and you have pressure. You RC gadget will require very little pressure to fill, if it is the Mylar balloon blimp/flying saucer that I think you may have. In fact, if you collapse the balloon to start with, you may be able to fill it directly with the generator.

John

 

[Boncuk]

Very interesting stuff!

I wonder what local authorities will tell the seller of hydrogen filled balloons during city fairs.

You will certainly admit that the mixture of hydrogen and oxygen is a very high explosive stuff!

Charging a lead-acid-battery hydrogen and oxygen are being "produced" when the battery is "boiling" at a charge voltage of < 2.4V per cell.

Charging in an unventilated room will cause a flame inferno if a spark of a light switch ignites the mixture.

I just wanted to point out the risk of accidents if something unforeseen happens.

My friend, a professional welder with all possible licenses up to pressure pipes in nuclear power plants got burnt 60% of his skin when an oxygen pipe (200PSI) broke while he was welding near the broken pipe.

He stayed one year in hospital undergoing many skin plantations.

If you want to carry parts of your a..s on your chin just go ahead and use hydrogen.

Boncuk

 

[Diver300]

A couple of balloons of hydrogen is not particularly dangerous. It will burn if you put a match to it, but there is far less energy available than in the fuel in a cigarette lighter, let alone the petrol tank in a car.

A balloon full of the wrong mix of hydrogen and oxygen will make a loud bang, and could be dangerous, so it is important to make sure the oxygen is separate if you electrolyse water. The gas from batteries is dangerous, simply because the hydrogen and oxygen are mixed.

Pressurised O2 is quite dangerous simply because it will make stuff that you wouldn't think of as inflamable, like steel or skin, burn, and stuff that would normally burn will burn far faster in oxygen. However, small amounts at low pressures don't produce a significant risk. The OP is looking for 10 litres of hydrogen, so about 5 litres of oxygen will be produced. There are about 4000 litres of oxygen, (along with 16000 litres of nitrogen) in the room I am in.

 

[()blivion]

If you want to carry parts of your a..s on your chin just go ahead and use hydrogen.

bak bak bak bak BAAAAK bak bak....
View attachment 65952

Hydrogen by it's self is no more dangerous than any other flammable gas. It's the oxygen part that starts to get dangerous.

They used to do space vehicles with the crew compartment filled at ~100% oxygen. Then some astronauts burned alive and they stopped doing that. Turns out every day household items (such as Velcro) become as flammable as gasoline when in a pure oxygen environment. And of course, if you finely divide and evenly mix any fuel with oxygen, it becomes an explosive(deflagrating or detonating) mixture. And gases tend to do this automagically, so your concerns are not entirely unjustified.

Edit: Diver300 beat me to it I guess -/)

"ze zeppelin" that "exploded" (burned down) was a massive disaster because of the shear size and number of people involved. My balloon is quite small in comparison and should only involve me, so I'm not that worried.

This is the piece of equipment you need:
**broken link removed**
Seal off the tube so the gas will enter a balloon.
Keep letting out the oxygen.

Hummm.... I like that apparatus. To bad it's glass. But then again, I suppose it doesn't have to be. The problem I see with that is that I'm going to have to use large voltages to get the before mentioned ~27 Amps to pump out, do to the large spacing of the electrodes. I suppose I could use direct off-the-line power, then I can add electrocution to the ever growing list of dangers.

The balloons are normal everyday large rubber balloons. So they will require some kind of pressure to inflate. But if one blows them up (no explosives related pun intended) a few times they will stretch out, which will make it easier to fill them later.

I don't want to use mechanical pumps, that involves complexity and I believe that the generated pressure is enough to inflate such things. Just need to trap the gasses and force them through a particular port.

Anyway, Good stuff guys.
-()blivion

 

[jpanhalt]

A single balloon with only hydrogen in it will probably not be too dangerous.

Hydrogen by it's self [sic] is no more dangerous than any other flammable gas. It's the oxygen part that starts to get dangerous.

That is not quite true. Hydrogen flames have a very fast propagation rate. They can flame back into a cylinder more readily than other combustibles. You cannot blow out a hydrogen flame, at least not using usual techniques. Hydrogen flames are very hot. Pure hydrogen flames are nearly invisible. The good part, they don't leave any black soot behind.

You know, of course, that methane (natural gas) is also a lifting gas. Its molecular weight is 16, so it would take more to lift the same weight as compared to hydrogen or helium. On the other hand, it is generally more readily available.

Finally, if you are going to do electrolysis, have you given any thought to the electrolyte you are going to use?

John

 

[Boncuk]

bak bak bak bak BAAAAK bak bak....
View attachment 65952

I consider that being an affront!

Over and Out!

Boncuk

 

[()blivion]

I consider that being an affront!

He he. I'm only teasing you of course. Your advice was well deserved.

if you are going to do electrolysis, have you given any thought to the electrolyte you are going to use?

Some kind of salt, and a non corrode able pair of electrodes I would assume. Why? Did you have anything particular in mind?

 

[KeepItSimpleStupid]

John:
Your absolutely right with the Hydrogen stuff. Confirmed from experience. Large explosions (when a lab blew up and my safety system worked - root cause was .a defective safety device) leave nothing burt and the flame is invisible (my glass blowing experience).

From my grade school days, I made some Hydrogen at home. Two test tubes inverted with platinum electrodes. I didn't have a constant current supply at the time. You could just make the oxygen dissapear. Ventilation would be required for safety. You have to use an inert electrode. I think it might be a slow process, but again it would depend on the area of the electrodes and the power supply used.

Once you make the hydrogen, you'll have to pressurize it.

 

[jpanhalt]

Some kind of salt, and a non corrode able pair of electrodes I would assume. Why? Did you have anything particular in mind?

Just wondering what you had thought about it.

Why won't simple copper, iron, or other metal electrode work for making hydrogen? Who cares what is happening at the oxidizing electrode from the electrode standpoint. However, you might want to consider what may be oxidized there besides oxygen. (hint)

John

 

[()blivion]

However, you might want to consider what may be oxidized there besides oxygen. (hint)

Hummm.... true true.