Liquifying Nitrogen: How is it done?

[MalliCk]

I know the undeniable substantial applications of cryogenics fluids in engg. sciences, but can't hold on how these fluids are cooled or liquifed from gaseous state??

 

[chemisttree]

At what pressure would nitrogen exist as a liquid at RT? How about at -80C?

 

[MalliCk]

^^

definitely not at RT, what i think!
:)
boiling point of N2 -196 C

 

[russ_watters]

It's done by utilizing the ideal gas law: when you pressurize a gas it heats up. If you cool it back to room temperature while maintaining the pressure, then let it expand through a nozzle, it cools down. Do that enough and you'll liquify it.

 

[MalliCk]

thanx

wish could have link for detailed citation

 

[phyzguy]

Try this:

http://en.wikipedia.org/wiki/Joule–Thomson_effect

 

[Q_Goest]

Air is separated in various ways, but the most common method is to separate it cryogenically. Here's a couple of references.
http://www.uigi.com/cryodist.html
http://www.che.cemr.wvu.edu/publications/projects/large_proj/air.PDF

 

[Mike_In_Plano]

The Joule Thompson effect will get you a temperature change by expanding through a nozzle, but for added cooling, expand in an expansion engine. Gas that does work loses energy ;-)