Pressurizing Gas.

[Bitter]

Making toxic chemicals and gas is one thing, but then what ? How are you going to store it for use ? Here's one solution to that problem.

A fire extinguisher. Up until recently, I have come across two types of fire extingisher; a cartridge powered one, that propels water or powder on to the fire, (the cartridges from which can be changed when they run out) and another called a 'stored pressure' extinguisher, which does not have a cartridge to replace and thus once it is used, it is ready to be thrown away. Look this up if you're interested, but I'll move on to the important stuff- I have seen a 'stored pressure' type that I'm sure had a 'refil' valve on it, near the handle. This valve looked identical to the one on a bicycle or car tire, with a thread to match too. Now, in theory, you could repressurize these with a bicycle pump (it had a pressure gauge too, to tell you when it was fully pressurized), or one of those that run off your car fag lighter socket. Now have a look at this :

<img src="http://www.jif2000.supanet.com/gas.JPG" alt=" - " />

If you were to set up an air-tight box as shown, it should be possible to repressurize the extinguisher with your 'favourite gas', being able to blast it off at the squeeze of a trigger. Just make sure a gas mask is worn !

[PYRO500]

You could use two freon compressors, they can get up to 400 psi when in series.

<small>[ August 31, 2002, 02:08 PM: Message edited by: PYRO500 ]</small>

[Boob Raider]

How many gases are out there which are desireable as CW agents but won't react with the Fe cylinder under pressure. The fire extinguisher is meant for relatively inert gases, like:- CO2, Halon, N2 maybe ? I am expecting most gases to corrode the shit out of the Fe to such an extent that there would be a leak or explosion, which might a really good way for gas dispersal but I can't say how long you can store whatever you want to store, and it also depnds on what you are storing. :p

[Bitter]

Well that's a different story altogether isn't it ? I assume one would make the gas only a few days or hours prior to use, but then again, it *is* a thick cylinder and even under pressure, the corrosion rate of most gasses would mean we are talking about a relatively slow process. I suppose it depends on the acidity of the gas, in the end.

[megalomania]

I don't think that many CW agents are all that reactive to things like metals. They do tend to hydrolyze with moisture, which may release undesirable flourine compounds. Now of course there are all manner of chemical weapons, but I was referring to nerve gasses. Even if a substance does react with the metal of the container, it may take some time (months to years) to cause a breech.

[nbk2000]

If you're using a compressor, then obviously we're talking about gasous agents, like chlorine or phosgene.

Most gasous agents are corrosive or flammable. This means the possibility of the compressor catching on fire, or the hoses/metal pitting and seizing up or disintegrating.

For liquid agents, many of them are also corrosive to iron because of the presence of chlorine, bromine, or fluorine in the molecule. When it breaks down (inevitably), these halogens are released and react with the iron.

Also, there's usually SOME acid impurities left over from the manufacturing process. The Iraqis Sarin shells were quite unstable after just a few weeks because of the HF traces causing pressurization of the shells with hydrogen gas (thousands of PSI) that'd force the agent out through the shell threads.

For storage, the home experimenter would be better off using cold liqification for gasous chemicals to avoid the expense of viton diaphragm compressors, monel steel fittings, and such.

Once your agent is ready, storage in plastic would be better than steel. There's no shortage of plastic 2 liter bottles in the world. Embedded in a milk crate filled with concrete, the bottles could easily keep phosgene or chlorine liquified.

Things like Sarin or Mustard, HDPE in concrete. You'd want to provide for a pressure release. Something as simple as a U trap filled with soda-lime and activated charcoal would work.

Adding an acid scavenger like pyridine to Sarin would bind up the HF for a while, delaying the inevitable degradation.

It'd also be a good idea to include a FREON chemical to your agent. FREON detectors can detect part per billion (or less) traces of these chemicals...concentrations lower then the agents mimimum irritating concentration, thus giving you ample warning of a leak.

[Einstein]

I was watcing the movie Chainreaction when I remembered this topic. Maybe that reaction bottle could contain plenty of water and two electrodes. Then you could compress H2 and O2 (separated from the water) to that fire extinguisher/some other container. Now only one spark is enough to blow the H2 and O2 mix in the bottle producing great explosion or fireball :D Could this idea work?

It would be like this: 2H2O ---(electricity)---&gt; 2H2 + O2
And when hydrogen burns, it becomes water, so: 2H2 + O2 =&gt; 2H2O
Form my point of view that should work. From two moles of water you get 2 moles of hydrogen and 1 mole of oxygen, and vice versa. So there SHOULD be enough oxygen to produce an explosion when ignited, right?

<small>[ September 08, 2002, 06:39 AM: Message edited by: Einstein ]</small>

[PYRO500]

Yes, but that has nothing to do with the topic. :rolleyes:

<small>[ September 08, 2002, 11:33 AM: Message edited by: PYRO500 ]</small>

[Einstein]

I don´t wan´t to sound irritant, but the topic IS "Pressurizing gas", so that is reason #1 for me to write here. #2 is that this hydrogen/oxygen filled pressurized bottle is VERY effect weapon/explosive/what-ever when ignited...

As far as I know about nerve agents or like, some of them are corrosive and some aren´t.

Generating gases isn't what the topic is about. The device you are describing is a Low Explosive and thus fits into that section. However, creating a thread there would likely get you HED seeing as it is kewl and certainly nothing new.

As for it being a "VERY" effective weapon, you base this on what exactly? The rigorous field trials against a variety of targets? Considering that you only just thought it up, it would seem you're pulling the opinion from the same place from which the device came - your arse.

I suggest you remove what is frankly, bilge that you have posted and replace with it something useful, that contributes to the thread.

No arguing with the staff!

I have witnessed with my own eyes when pressurised tank (20 liters, 34bar) "explodes". It was full of compressed air, but the pressure that was released was enourmous! Think that same thing but with flammable gas....

And my apology for being crude for staff (PYRO500), I didn't mean it in that way. It (my idea) really sounds like K3wL, but also the professionals have to have some fun when not making RDX, picric or similar :p And sorry for the off-topic.

<small>[ September 09, 2002, 03:57 AM: Message edited by: Einstein ]</small>

[Bitter]

I don't think you would need to ignite it, it would explode on its own under enough pressure. Think of how a diesel engine works.

[Einstein]

OT: Diesel ignites in temperature over 550 celsius and in very hi pressure...I don't think that the pressurized gas tank will be 550 degrees warm...and it won´t be diesel :p

<small>[ September 11, 2002, 09:35 AM: Message edited by: Einstein ]</small>

[Harry]

If we're going to be messing with fire extinguishers, allow me to add my own findings (specific to the upper Midwest USA):

1. Most, if not all, of the cheaper ones are aluminum.
2. Some stored-pressure models are reuseable, others (cheaper) are disposeable. The reuseable ones I've found in my area are repressurized through the discharge valve. Read the recharge directions.
3. Smaller units (2.5 lb) tend to be rated at 100psi, tested at 250-300 psi. 5 lb units tend to be rated at 250-300psi, tested at 500psi. Get a 5lb or larger unit. Or a CO2 unit, if available.
4. A valve can be installed quite easily into an aluminum model. Use a self-tapping threaded valve, or buy the appropriate tap for the available valve. In the Murderapolis area, valves with 1/8" and 1/4" NPT (plumbing) threads are available for under USD$2. These valves are compatible with your bicycle pump. Easiest place to install is the center of the bottom. Overbuild--use epoxy for extra strength.
5. Even the disposeable ones often have removeable heads--just unscrew from a FULLY discharged unit and dump the powder. Do this far from home, preferably in a dumpster, at night. Wear a dust mask. Open the dumpster only as much as necessary to fit your hand and the bottle.
6. 2.5 lb units tend to be disposeable aluminum bottles, with a plastic dip tube inside. 5 lb units tend to be reuseable, with all aluminum internals. On the used (thrift store) market, one can sometimes find reuseable 2.5 lb units made of steel. Disp. AL units are more common. Caveat emptor. Look for the 5 and 10lb units. Pay about USD$2-3 per unit. Hit yard sales, too. Pay $10 for a charged (5lb) unit. Cheap protection for your lab.
7. The 2.5 lb disposeable units have to be handled with care when disassembled--the valve spring assembly tends to break apart, requiring epoxy and ingenuity to fix.
8. For some reason, used fire extinguishers seem to be in fairly high demand around here.
9. Don't mess with the acid/soda models, except to hide stuff in.

This is from 5 years of messing with the things.

Harry Mann

[jimwig]

gee - the first thing that comes to mind is the purpose of pressurizing gas.

is long term storage -
is long term life of pressurizing equipment-
?

mr bitter's plan leaves a lot to be desired.

what sort of gas is being pressurized?
i would hope for an inert variety, also a gas that does not effect adversely the machinisms
emersed therein.

for it seems that an explosive gas - one that will oxidize with the atmosphere inside the
"gas filled chamber" will surely detonate.

(Bitter- Oh really ? :rolleyes: I never would have guessed that...and I could have sworn this topic was all about compressing poisonous, not explosive gases, hence the opening sentence : "Making toxic chemicals and gas is one thing,". Try being smart with me, or any of the other moderators again and you'll find yourself getting HED.)

the compressor should have an explosion proof, totally enclosed type NEMA 12 motor or else
the life expentancy would be brief. not to mention many other pitfalls of this design.

don't get me wrong - i just don't want someone in wide eyed wonder to blow their appendages
from their bodies because they followed this idea without checking the obvious resources for
safety, etc.

i also wish to direct those interested to an article in Scientific American
entitled "old refrigerators are salvaged to build a laboratory cooler and a gas liquefier"

November 1969 page 151

taking care to note that "freon" "r-22" is now a restricted and enviromentally unfriendly
little beast not to mention illegal.

anywho this seems to be a start toward homemade liquefication.

this little diatribe coming from 54 years of trying to get it right-
the first areas tried being atmospheric comingling and regret.

<small>[ October 02, 2002, 04:22 PM: Message edited by: Bitter ]</small>

[PYRO500]

As far as I know Freon is not illegeal, in fact I had my air conditioning units filled with R-22 a few weeks ago. I do believe however that you need a permit to buy it and you must use freon recovery tools such as vacuum pumps that pump the left over into a tank.

<small>[ September 29, 2002, 12:06 PM: Message edited by: PYRO500 ]</small>

[Anthony]

This might be interesting:

<a href="http://www.overclockers.com/tips1032/" target="_blank">http://www.overclockers.com/tips1032/</a>

It use a fridge compressor to make a CPU chiller, but it's rough and ready and should be of some use.

[jimwig]

"restricted" is not the same as illegal. grok it again.

go down to the HVAC store and try to purchase R-22. or for that matter go to the auto parts place like
Autozone and notice that the refill bottles don't say R-22 anymore. I think its 34a or something like that now.

there's federal laws that prohibit the sale or use of R-22 and other refrigerants by unlicensed indiviuals as well as
the release of these gases into the atmosphere. so it is indeed restricted. and there is also a huge gray market from
Mexico (et al) in the smuggling of these.

anywho here's somemore solid data refs for those prone to be serious about this gas generation and storage topic

(patents) http://gb.espacenet.com/

US 1429242 sepration of gaseous mixtures - mostly just that but some interesting stuff on fractionation and storage
US 1521138 liquefication of gases - the real deal on a large scale but the principles are relevant. great graphic of
industrial fractionating column - could be scaled down to the garage version.

[kingspaz]

jimwig, watch your attitude towards moderators. they are much higher up the tree than you so show respect or leave. its you choice.

[Boob Raider]

I bought a Dry Powder type fire extinguisher for $0.50 at a church rummage sale. It is rated for 300 PSI. I was wondering if I can liquify air in it with a suitable compressor. In other words what pressure does air liquify at ? .... BTW what is the powder in the extinguisher. Eitherways staring fires/barbecues will be a snap with compressed air at the command of your thumb :D . What else can compressed air be used for in an extinguisher cylinder ?

[Anthony]

The critical temperature of liquid air is approximately -195°C, so yeah, good luck with that.

"Eitherways staring fires/barbecues will be a snap with compressed air"

It'd be as easy as if you blew on it, but without the lung work.

"What else can compressed air be used for in an extinguisher cylinder?"

PC duster? Making "psssst" noises? That's about it.

[Boob Raider]

Thanx Anthony .... Oh I just thought of something ....... If one was to sabotage the fire extinguishers in a building with say compressed air cylinders and/or fuel cylinders and rig the release valves so that once fired the gas flow can't be turned off ..... even a garbage can fire would burn down the building. Water sprinkler system even if left unsabotaged won't be much good as there is already lots of fuel and air in the rooms and the heat is quite high.
Also if I were to replace the drypowder with say Mg powder ..... what kind of propellant should I use ? I am assuming CH4 should be good. And if nothing works ... paint ball gun it is.

[Harry]

Raider, Dry Chemical powder is largely Sodium Bicarbonate mixed with...crap, I don't have it listed on the 2 I have on hand. The 2nd chemical is a real pain in the glutes--a light dust, it seems to be wet-resistant, gets all over everything. Follow my previously-posted instructions.
Excercise some restraint when it comes to sabotaging fire extinguishers--in the event of a fire, it would most likely be one of US or a like-minded one who had the mental presence to actually use an extinguisher. Of course, if you're Stateside, in a Campbell's Vegetable-type office, you might have some fun, but burro-crates have survival rates similar to cockroaches.

As for other uses for an aluminum (or steel) pressure vessel, check PMJB, IIRC vol 2, the speargun article. There's a reason why I discourage use of sub-5 lb units.

Harry

[jimwig]

bitter- sorry for crossing up the works but consider this

toxic gases could be explosive -neither is mutually exclusive and no specific gas was mentioned.

your plan would work but exclusion of oxygen would be desirable in any type of gas. if you are trying for some level of purity.

my comments were in all good faith aimed at safety...

[zeocrash]

military gasses generaly tend not to be explosive, as they would not be much use on a battlefield with lots of fire and bombs and explosions. if they exploded they would turn into other things that may not perform the desired effect, although a binary agent that reacts with air to form tyhe nerve gas, is a clever idea.
anyway military gasses either tend to be corrosive, or cholinestearase inhibitors.
G - agents are slightly corrosive to steel
phosgene is not corrosive, as long as it is dry
V agents are non corrosive, but decompose at a rate of 5% a month
as for the rest, the message from the US army chemical weapons hnadbook appears to be that they wont corrode their containers, if they are kept dry.
also, housold bleach is listed as a decontaminating agent for every lethal gas except nitrogen mustard. so it might be an idea to store your cilinders of lethal gas in a bath of bleach.
for tearing agents (lachrymators) the deconatmination method suggested is alcoholic caustic soda.
soap is suggested for removing cs gas, the more alkaline the better, (do not use chlorine bleaches, it releases toxic fumes)
chloropricin is destroyed by sulphide solutions.
also an idea for increased safety for your gasses is to store your gas as 2 binary components and mix them on use. this could be done by putting 2 fire extinguishers in series. the first extinguisher would be pressurised, the second would not be. on triggering, the first extinguisher would blast the engredients into the second extinguisher, where the reaction would occur, seconds later you could then trigger the second extinguisher, which would have been pressurised by the chemicals being forced in from the first fire extinguisher. for safety you should always make sure that the least dangerous chemicals are in the pressurised container

[zaibatsu]

For a binary agent, would it be possible to adapt a t-junction piping connector (not sure of the correct name) with a valve on the bottom of the T. Screw both cylinders in partially to seal the T, and then screw one then the other in fully. You'd have to build into the T some way of depressing the valves. Then, turn the tap, or if you can use a solenoid, set the timer and place it.

[Chade]

Boob Raider mentioned liquified air. Even with a compressor working at 300Psi (20 atmopsheres) you won't manage this. The critical pressure for nitrogen to liquify is 39 Atmospheres. Almost double. To liquify air, you'd need a very special pump indeed. In fact, by the method generally used (Linde process), you'd need to get up to 150 atmospheres. That's a lot more than most commercial pumps. Also, the pump would have to work at cryogenic temperatures. That means very few moving parts. Essentially, the pump would need to be custom made.

I'm not going to go into the finer details of the Linde process here, but the low temperatures are reached by allowing the pressurised air to repeatedly escape. This creates cooling just as spraying an aerosol on the back of your hand freezes your skin.

I'm very tempted to try building my own pump, despite the fact that it would be one hell of a job. Just imagine the uses for liquid oxygen on tap. Even at much lower pressures, you can compress and release CO2 to make your own dry ice. All exceptionally useful for a variety of projects. As NBK said, a simple bottle embedded in concrete will take a pretty hefty pressure (although I'm not sure when the concrete might start to fracture) So all that's needed is a suitable pump, and you can store much larger amounts of gas in a smaller space, which is the main reason these gases get compressed in the first place.

[tmp]

Just want to pass on this information about FREON.

I have an EPA 609 license. It's required to purchase chlorinated refrigerants for air
conditioning systems. The only reason I got the damn thing is so I can puchase freon
for the cars of my family, friends, and myself of course without having to pay
the outrageous fees to so-called "professionals" to recharge the car's "air".
This license is also required to even service these vehicles. The EPA and numerous other so-called "ozone layer depletion" experts have determined that the
chlorine atom in many refrigerants is responsible for the depeletion of the ozone layer. It refers to any number of refrigerants that use the chlorine atom but
most commonly R-12 and R-22.

[redbull]

Whenever Im generating gasses for a chemistry project I
usually dont need pressure over 30 PSI. However many
(most?) fire extinguishers designed for CO2 have removable
tops. Internally, they are Aluminum or Steel. You should be
able to PTFE (teflon) coat the insides or otherwise apply
a corrosion resistant coating on the internal walls of the
cylinder. Ok, now that you have two fire extinguishers you
need to visit the hardware store and buy compressed air hose
and fittings... the hose is rated for 300 PSI but in reality
its good over 1000 (I think 1200 is the hard limit) The package
will give you specifics. Use the hose plus the fittings to construct
a hose in the shape of a "T' where there is a hose going to each of
the two (or more) fire extinguishers and there is a valve on one
of the hoses and that is a pressure release. This hose is very long
and is possibly submerged in a liquid / chemical to facilitate either
recovery or netrualization of the toxic gas.

Hypothetically, lets say we're making chlorine gas...
Unscrew the lid of one of the fire extinguishers (make sure they're all
empty first) and add powdered calcium hypochlorate. Then insert a
glass cup / container that contains concentrated Hydrochloric acid.
Seal up the container again and you should have powdered sodium
hypochlorate on the bottom of the tank and this liquid in a container
either open or closed. Now once everything is sealed up and you have
opened the release valves on all the fire extinguishers and closed the
release vent line. Tip the reaction extinguisher over. The chemicals
mix and start to produce chlorine gas. Fine particles of sodium hypochlorate
will dissolve faster makign higher temps and pressures quickly. I would
advise geenerating pressure slowly and using a bottle with a plastic top
that had a small needlehole so the gas would be generated slowly.
Do the math and figure out how much gas you can generate before
you burst the container... that way you know you will be safe. The
gas will evenly pressurize over all the containers. Use pressure guages to
see how much gas the tanks have and then cut off the pressure release
handle and turn on the gas vent line. Disconnect the tank and add another
tank if your doing this assembly line style.

After your done let the gas vent to the trap or open air via the vent line.
Open the tank up and clean it out.

HINTS : If your reaction tends to generate heat, regulate the heat at
the source in the generator tank to avoid pressure problems.

Use lots of hose coiled in an upright spiral incase of reaction chemicals
foaming up and out of the container. Surrounding this line with ice
can keep foam down.

If your intrested in anhydrous gasses try filling up an extinguisher with
an appropriate dessicant, but make sure to take up most of its volume
so your not wasting gas. Make sure your hose is constructed with valves
that will allow you to cut off the generator and vent line but allow you
to turn the dessicant fire extinguisher on and off. The gas will distribute
itself evenly throught the network of hose and fire extinguisher chaimbers.
The dessicant chaimber should get most of the moisture over time... just
let the whole setup sit for a while.

The line is the weak part of the system, replace it with metal tubing to
increase network pressure.

If you exceed the reccomended ratings but are otherwise with the max
pressure rating becareful to watch the factory installed emergency pressure
release disc / valve, you may have to remove it or disable / bypass it.

MISC :

A 5 Lb CO2Fire extinguisher can take something like 2000 PSI before
the cylinder will burst, emergency pressure release discs may vary.

Excluding fire extinguishers, you should be able to get everything else
for 50 USD.

Fire extinguishers can be easily aquired at no cost (i.e. stolen) from many
busisnesses.