Sciencemadness Discussion Board

Gas separation membrane (how-to-get-pure-N2)

chucknorris - 13-12-2012 at 15:23

Are these gas separating membranes available for commercial sale or are they still at the prototype stage? Intention is to obtain pure nitrogen gas.

Other plan I had in mind was to first drive the atmospheric gas through gas burner and then bubble it through hydroxide scrubber, a process that will turn free oxygen into CO2 and react it with hydroxide to make sodium carbonate and leave nitrogen and trace amounts of other gas left.

CaliusOptimus - 13-12-2012 at 15:35

I'm sure you've considered this, but I'm going to mention it anyway.

Compressed N2 is cheap and widely available. The cylinder itself will cost at least a hundred bucks though.

kristofvagyok - 13-12-2012 at 15:36

There is a reason why they make nitrogen by distilling liquified air and not by passing it through a membrane.

Also making N2 by burning out the oxygen and the remove the CO2 from is a lot energy and work for the cheapest available gas. Buy a cylinder of it, it's cheap, really cheap.

chucknorris - 13-12-2012 at 15:53

By means of making ammonia from it and H2, I'll give it a thought, but just to say, anything in my country is not cheap. Dry ice will cost 15 euros a kg, and nitrogen will cost 10 euros per kg in gas cylinder. I actually just checked it a couple of weeks ago when I got some welding gases. Even food costs a shitload in here, normal person easily consumes 500 euros a month for normal food if one doesnt want to eat only porridge.

kristofvagyok - 13-12-2012 at 16:05

Dry ice costs here the same, but if you need it, you will pay for it, easy.
For the 10Eur/kg of nitrogen: its a fair price. Let's calculate a bit, it's a bit more than 35 mol. The carbon source, the power what you need to get out the O2, the lye what you would use to get rid of CO2 would also cost that much, or even more. And the most important thing: your time.

P.S.: home made ammonia factory always end up with several problems and less success. Keep it in mind.

Adas - 14-12-2012 at 06:26

Here I can buy 5kgs of dry ice for approx. 8€. You have very high prices there. :O

watson.fawkes - 14-12-2012 at 08:00

Quote: Originally posted by chucknorris  
Are these gas separating membranes available for commercial sale or are they still at the prototype stage? Intention is to obtain pure nitrogen gas.
They're commercially available. To pick one supplier I've looked at, Parker sells nitrogen generation systems, though not in tiny packages. Parker probably does not make the underlying membrane. I don't know who does. Even if you could find it, you'd need a compressor and flow rate regulation system to drive it.

Like all sorts of issues, the question as stated is underspecified. How pure do you need it? How much do you need? The answers about how to do this change depending on these answers.