Sciencemadness Discussion Board

DIY gas cylinder?

numos - 23-2-2014 at 22:46

Most people make Chlorine gas as they need it, I personally use the HCl and hypochlorite method, and although this isn't too much trouble, it often means I have to watch two reactions at once. Wouldn't it be nicer to have a cylinder of chlorine that you could regulate with the twist of a valve?

I imagine powerful pumps are used to fill gas cylinders in an industrial setting, but how about with DIY materials? Apparently, chlorine reaches pressures of around 100psi in a cylinder.

SO... I'm thinking make a cylinder out of a length of pipe with two end-caps and a hose with a valve coming out of it. Liquid chlorine could then be poured into one end of the pipe and capped. As the chlorine vaporizes it pressurizes the pipe and allows it to be used as a cylinder...

One drawback I ran into - what material to make the pipe out of? Stainless steel? Steel pipes that they use in gas lines? Dry chlorine would work with stainless steel right? To dry it I would simply bubble the Chlorine through conc. Sulfuric acid?

Would this have a chance of working?

Sources:

http://krebs-swiss.com/cl2drgpi.htm
http://www.bssa.org.uk/topics.php?article=38

Marvin - 24-2-2014 at 02:46

Please leave your personal information with a member of staff so that when you have killed yourself we have closure.

I'm not joking.

Metacelsus - 24-2-2014 at 05:59

If you do decide to go ahead with this, test the cylinder to 100 psi (or more) with a benign gas first!

How do you plan to liquefy the chlorine?

[Edited on 24-2-2014 by Cheddite Cheese]

Marvin - 24-2-2014 at 06:54

Unless the container is specifically designed for chlorine, and known immune to corrosion in all it's parts, a pressure test won't help.

A homemade tank of chlorine is a chemical warfare event waiting to happen. If he's lucky, he will only kill himself and his family.

Zyklon-A - 24-2-2014 at 07:20

Yes, I once heard of an accident, where someone tried to fill a canister with liquid chlorine. Something went wrong, all the chlorine leaked out, and the entire (small) town had to be evacuated for a few days.

numos - 24-2-2014 at 07:23

ok, ok... that's all I needed to know. It won't work... this is why I asked :P

markx - 24-2-2014 at 08:53

I worked on high temperature carbide chlorination reactors for years and I can tell you that chlorine will corrode almost everything...plastic, stainless alloys, regular steel alloys, inconel types, people. It is just way nasty stuff. All of our setup was constructed from stainless, but it rusted so fast you could almost hear it. We used high quality items in the construction of gas delivery and metering systems (Swagelok stainless fittings, specialty valves and reductors), yet there were reglular breakdowns and leaks due to corrosion. The only thing that resisted was PTFE....so long story short, a homemade chlorine cylinder is a really bad idea. If even the commercial systems could not keep up, then I would not trust any homemade one not even as far as I can throw it.

numos - 24-2-2014 at 15:45

So how is chlorine used in industry? They must have huge stockpiles of it stored... in what? From what I'm seeing they are stored in normal gas cylinders. Just search "chlorine cylinder". Does it degrade that too and they just have to use it quickly?

Zyklon-A - 24-2-2014 at 15:59

This should help. Steel is the answer.

chemrox - 25-2-2014 at 11:21

Making a Cl2 cylinder seems the height of recklessness for a DIY project. Generate in situ or buy a cylinder. Tank explosions can result from traces of cutting oil. I was at a garage in the midwest where I was getting some repairs on my car done. The owner had just lost a mechanic to a welding tank explosion. This was a conventional tank that had pulled a little oil in when emptied and was full again when it blew. I'm not opposed to DIY but this is more risky than a liquid fuel rocket.

macckone - 25-2-2014 at 15:18

Commercial chlorine cylinders are steel.
The trick is that the chlorine stored in those cylinders is DRY.
It is theoretically possible to refill a cylinder but not easy.
You would have to remove ALL of the moisture in the gas
before compressing it. And the compressor can't allow any
oil to come in contact with the chlorine.
This just doesn't seem safe or feasible for a home chemist.

Manufacturing chlorine gas and using it immediately is probably
best. A less troublesome method of producing chlorine is
electrolysis. It will prolong your reaction a lot but it is unlikely
to go badly and will allow you to concentrate on your main
reaction.

testimento - 26-2-2014 at 14:11

You will gonna have to first lead chlorine through drying, like conc. sulfuric acid or large pile of anhydrous CaCl2 and then through steel pipe coil which goes through ethanol dry ice or CaCl2 + water bath to condense the chlorine and then into your cylinder which is also submerged into cold bath to keep it liquid. You need to bake the cylinder at 300C for few hours to drive out all the moisture.

100PSI is very easy to reach, just find normal steel tubing and thick end plates, like 10-20mm minimum if you cannot find conical. The big point is welding them up, there you will need a good tig welder and some skill to make it proof. When done, wash the cylinder with citric acid for few hours, then wash it and fill it with water up to 100% and install meter with normal tube fitting and then push in air for 200PSI, if it's ok and pressure stays, you have good cylinder, now dry it by baking in oven and you are ready to go. Its a problem to get the chlorine out there, you will need steel or monel valve. Its still a very good idea to store the cylinder in safe place in case of leaks.

I think so too its a wise idea to make chlorine when you need it, by electrolysis or then by reacting chlorine stuff like hypochlorite or TCCA.

Electra - 9-3-2014 at 23:43

Please do NOT try to build your own cylinder.

I have experimented with pressurized cylinders in the past. I suggest checking these out.

http://www.x2industries.com/tanks-gallon-port-polished-stain...

They sell smaller cylinders as well, but none rated at 1000 PSI like this one I believe.

These 5 gallon cylinders made for car air systems are made of stainless steel and are rated up to 1000 PSI. Make sure you get the proper steel fittings as well for regulating your gas. You may need to look into a proper regulator as well. For your purposes and many other low-weight single atom gasses, you should invest in a CGA 350 regulator valve, which can easily be $500. These valves are required to bring the PSI down to 5-40, other wise you will run into trouble when it comes time to release your gas.

Please do not build your own cylinder, use one that is pressure tested. If you are doing this as a hobby, I simply suggest getting another hobby. If you need chlorine gas, I suggest purchasing it, or making it on command. For the Hobby Chemist this is generally not something you should feel safe with lying around, even if it was partially rigged up from up to standard supplies.

I used to store a lot of anhydrous gasses as easy sources of pure acid, but after one close call from not paying attention, I came to the conclusion they are not worth the risk to have laying around. They don't make things that much easier. Sometimes you just have to make a judgement call between safety and convenience. If you are going to do this, make sure you do your research and use the proper materials.

khlor - 17-7-2014 at 21:36

So that is the why I didn't found any result about diy chlorine gas cylinder. what if I make chlorine gas, but I dont want to use it, is there any safe way to store it? or less dangerous? can I store it in a compound that I can easily put some reagent to release the chlorine later? I mean, I reac the chlorine gas with something and later use this something to give of chlorine as in an easier way later? if not is there any option?

gdflp - 18-7-2014 at 06:42

You could recycle unused chlorine by bubbling it into aqueous sodium hydroxide, regenerating sodium hypochlorite.

m1tanker78 - 19-7-2014 at 14:42

I collected ~ 250mL of liquid chlorine in a flask from a Downs Cell once. After a few little experiments, I transferred the rest into a small modified propane cylinder (the handheld type).

The chlorine that comes off a Downs Cell is as close to perfectly dry as it gets but it took a fairly elaborate setup and quite a bit of dry ice to carry this out. I confess I was pretty nervous especially with the propane cylinder bit of this experiment. As a matter of fact, I didn't even let it climb to ambient temperature. I slowly bubbled the CL into the swimming pool and was glad to be done with it!

Afterward, I cut the cylinder open and aside from a little browning of the inner wall, there wasn't any apparent attack but in fairness, it contained the COLD chlorine for only a few minutes. I've cut other propane cylinders open after emptying and purging and they have the same browning as well. The thing that REALLY worried me was the VALVE. Unfortunately, there was no easy way to verify the valve's integrity. If I'd done this experiment at, say, a ranch, I wouldn't have been too concerned about the gas cylinder / valve failing. I would have even given it a proper set of destructive field tests ;)

Oh and yes, I tested the pool's free chlorine level afterward and it was literally off the chart. Never seen the indicator turn that color before.

Be very very careful around chlorine. It really is nasty stuff and a sudden, unexpected release could make for a very bad day ---- or good day if you wish to die, become blind, melt your respiratory tract, etc.

Small quantities first. Test your apparatus to ridiculosity and then some.

Tank

neptunium - 20-7-2014 at 05:21

although a very bad idea.. if you have access to nickel and large quantity of PTFE the passivation of the metal should keep it under control. thats how Fluorine is being kept.

This enterprise seems too dangerous and out of reach for a home scientist.. it is in fact easier to start a nuclear reaction of any kind at home..

plante1999 - 20-7-2014 at 05:46

May you give us more detail on your down cell? This kind of hardware is not very common for amateur.