[imsmooth]

hello all.  I happened to find this forum while searching some chem topics.  I thought this would be a reasonable place to show off a project of mine.  Hopefully, I will have things to contribute as well as have questioned answered.

I had the idea one day to make liquid nitrogen from air without the use of a cryocooler device.  Below is a tutorial I put together for others to replicate if they so choose.  The project involves high-pressure gases, so extreme caution is required.

Here is the link http://homemadeliquidnitrogen.com.

[Darryl1]

Wow, that is really cool.  Out of curiosity, what does it cost to generate 1 liter of liquid nitrogen?  I guess factoring in electricity and consumables.

-d

[imsmooth]

The only cost is electricity.  I generate my N2 (98-99%) from air using a pressure swing adsorbed that I fabricated.  There is a link within the tutorial to that project.  The compressor pressurizes the N2 and I throttle it down to ATM pressure reduce the temperature.  The approximate costs for the LN2 generator:

compressor - $1500
steel pressure tubing $100-150
teflon tubing - $400
insulation - (I got this for free, but it probably is a few hundred dollars)
form tube (free)
steel fittings - $100-150

You will also need machining tools to fabricate connectors

[Corribus]

That's pretty damn cool, but probably too much money (and work) invested for me to make some (admittedly very good) ice cream.

[Darryl1]

Corribus, liquid nitrogen ice cream is the best way to make it!  I tried making some with dry ice once and it turned it carbonated and it had that oddly sour carbonation.  It would have worked great for a sherbert, but not ice cream.

Anyway, I've heard that Fermilab uses truckloads of liquid nitrogen a week.  It would be interesting if this design could be scaled up and if they could save money in the long run.  Imsmooth - perhaps you could build kits and make some money on the side.

-d

[imsmooth]

Unfortunately, a kit for this type of setup is out of the question.  I could offer a set of plans,but I've already done close to that with my tutorial.  The closest thing to a simple do-it-yourself is using a cryocooler.  However, this isn't really do-it-yourself.  It's like learning how to make ice at home by buying a refrigerator.  In my case, I made the refrigerator.

[curiouscat]

Anyway, I've heard that Fermilab uses truckloads of liquid nitrogen a week.  It would be interesting if this design could be scaled up and if they could save money in the long run. 

-d

Why do you think this is cheaper? Have you compared the running cost of this versus commercial truck tanker N2?

[Arkcon]

Anyway, I've heard that Fermilab uses truckloads of liquid nitrogen a week.  It would be interesting if this design could be scaled up and if they could save money in the long run. 

-d

Why do you think this is cheaper? Have you compared the running cost of this versus commercial truck tanker N2?

I think the issue is more about availability.  People don't actually buy liquid nitrogen or liquid argon for the GC's MS's or ICP's.  They contract with a supplier for a service.  The contractor supplies an external tank, and monitors the pressure.  When they notice its getting low, the contracted company schedules a delivery of liquid to the Dewar, maybe even late at night, and the end user never has to worry that they might get low.  This really comes in handy for overnight analytical runs.

Still, I'm thrilled at this thread, I really might want to make the liquid nitrogen ice cream this summertime.  If I have time, and space, ...

[curiouscat]

I think the issue is more about availability.

Yes, availability too. But even on a $/kg N2 I think the commercial suppliers will be cheaper than a DIY unit. There's also economies of scale.

DIY is great fun. And I'm fascinated by this project too. I'm just saying that it may not be the best way for a large user like FermiLab.