A little bit OT question about generating ntirogen

It is only a real risk if you accidentally concentrate the O2 which has a slightly higher boiling point and much worse if you manage to end up with any liquid ozone (darker blue) which is inclined to detonate.

LOX plus almost anything is inclined to serious conflagration or if provoked detonation. It is a lovely pale blue colour and strongly paramagnetic which allows for a couple of amusing non-pyrotechnic demos. I know someone with their own LOX still (now retired).

nitrogen,

Simple method if it doesn't have to be too pure is to use up all the oxygen by burning charcoal in it and then you have an N2 CO2 mixture. Or at a pinch a wax candle which leaves some water too.

You could scrub out the resulting CO2 with KOH if you wanted, but it will be solid at LN2 temperatures so you probably don't need to bother provided your kit can stand it being solid phase.

Caustic NaOH will probably do at a pinch. They are almost certainly doing something similar to what I suggested above. Burn carbon in the air stream and then scrub out the resulting CO2.

Removing the Argon is somewhat more tricky by distillation.

Given the price of LN2 I have to wonder why you don't just order some.

Regards, Martin Brown

Generically, these days, you are looking for a membrane nitrogen concentrator - but they all seem a bit high-priced - though perhaps somewhat less high-priced than the specific model you are looking at if you get the commodity item, rather than something pointed at car owners with too much money.

PSA is another option, but involves more complicated machinery (and more air compressor run time, thus money to run - but you might find something surplus, as it's old tech.)

I rather suspect your compressor run cost equals or exceeds the cost of buying LN2 - and certainly the cost of a membrane concentrator will buy many liters of LN2...

Jan Panteltje schrieb:

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Hello,

I believe there is something wrong. They sell hydrogen generators too, the hydrogen is made by elctrolysis of water and KOH is no catalyser here, it is simply necessary to let the current flow through the water. Maybe they mixed up the description of the nitrogen generator with parts of the description of the hydrogen generator.

It is possible to get nitrogen out of the air, it is also possible get hydrogen out of water, but it is not possible to get nitrogen out of water. As we should know here, water consists of hydrogen and oxygen, but there is no nitrogen within this chemical compound. Nitrogen may be seperated from air by to methods: liquify the air and seperate by destillation or filtering the air with pressure through the walls of tiny tubes.

Bye

nitrogen,

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Many moons ago I ran an old nitrogen liquifier. It had this tall tower (~3 meters), that I belive did fraction distillation of the Oxygen and Nitrogen. You could turnn a big valve on the side of the machine and switch from LN to LOX.

But why are you trying to make your own LN? I thought your goal was just low temperatures? If you want LN I bet you can have it delivered to your door for less than a euro per liter. I've got a 60 liter nitrogen dewar, for $95 a truck will come to the loading dock and fill it up*. I think the price would be about the same if it was a 200 l dewar. Most of the cost is for the truck and driver's time. The LN is cheap. The dewar holds for about 2 months. I've got a colleague who claims his new LN storage dewar can hold for six months.

George H.

On a sunny day (Thu, 7 Jul 2011 07:01:13 -0700 (PDT)) it happened George Herold wrote in :

That would be a bit big, and pricy too I think.

Well, I am just experimenting,

Sure, I can cool things to close to 70 K, but there is some (a lot) of vibration from the cry-cooler.

So for some experiments I want to have a dewar of LN at hand.

You can have *anything* delivered to your door, providing you pay for it. With anything I mean from Apollos to submarines, what not.

Yea, but then what fun is it.

Think of what you can do with the LOX :-)

hush hush

Maybe one day niagara falls will be frozen, some sight. Yesterday I did see a documentary about China, there was this guy jumping of a

On a sunny day (Thu, 07 Jul 2011 15:23:09 +0200) it happened Uwe Hercksen wrote in :

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Yes electrolysis of water, works great, you can blow bubbels with the resulting gass and detonate thoise with a match.

Sure, but you can have someting react with the oxygen, bind the oxigen from the atmosphere, that leaves N.

H2O

Or just burning a candle in a container until it goes out, that gets rid of the oxygen too.

On a sunny day (Thu, 07 Jul 2011 12:24:55 +0100) it happened Martin Brown wrote in :

nitrogen,

OK, thank you for the info.

OK

One has to have done everything in this life, or as much as possible. Just go with the flow.

Jan Panteltje schrieb:

the atmosphere, that leaves N.

Hello,

all noble gases like Argon, Helium and so on would be left too.

There are much better ways to get Nitrogen out of air than to make hydrogen out of water by electrolysis only to burn with the air to leave water vapor and nitrogen. To much electrical energy is necessary for that way. The hot flame will generate some nitrogenoxides too. If the ratio of air and hydrogen is not correct, there will be some left hydrogen or oxygen within the nitrogen.

Forget this ebay dealer with wrong descriptions of the machines he wants to sell.

Bye

nitrogen,

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Fractional distillation? Then find a way to vent the O2 off?

On a sunny day (Thu, 07 Jul 2011 09:55:40 -0700) it happened Tim Wescott wrote in :

nitrogen,

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Yes that thought had occured to me. But then I am not a chemist, so I am dangerous doing that :-) LOL

On a sunny day (Thu, 07 Jul 2011 18:02:25 +0200) it happened Uwe Hercksen wrote in :

the atmosphere, that leaves N.

I am still not convinced that description is wrong, look up the reply of Martin Brown in this thread. But I admit I do not understand exactly how that thing works either. But looks like you can make your own. We need some chemical expertise here, maybe Dr Sloman?

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LN is great fun to play with, and not very dangerous. I've never touched LOX. So I'm a bit frightened by it. You could try making a dewar full of liquid air and then decant the LN off the top. (I think the LOX is more dense.) But what will you do with the LOX? (Don't pour it on your charcoal grill :^)

George H.

of a 20 meter high

nitrogen,

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"TyreSaver3" ??? What is it about PV=nRT that suckers like Panteltje don't understand ?:-) ...Jim Thompson

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Automotive version of oxygen free audio cables? Art

There's also a form of zeolite called "molecular seive (sieve?)" that's used in an "oxygen concentrators" - it literally filters the nitrogen out of the air; just use that instead of the oxygen output.

Have Fun! Rich

nitrogen,

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It seems to me that a bit of rework on something like this will get you what you want

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I think so ;-) ...Jim Thompson

-- | James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at

On a sunny day (Fri, 08 Jul 2011 08:59:24 +1000) it happened David Eather wrote in :

nitrogen,

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this thing:

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That is beautiful, thank you!