Auto Grade Nitrous Purification

Comments on Filtration Systems

We had some great times at my college with a 64-pound tank and a 2-chamber filtration system. The nitrous was first bubbled through a relatively strong baking soda solution in a 5-gallon bottled-water water-bottle. (Strong = about 2/3 of 16-oz box.) Then it bubbled through another bottle with half the concentration. (the other 1/3.) Then it bubbled out. Rubber stoppers and 1/2" plastic tubing formed the rest of our equipment.

Sadly, the pressure when it flows out of the second chamber is too low to fill balloons. But when you've got a tank, the thing to do is fill kitchen garbage bags that have tubes sticking out & rubber bands wound around the neck for a nice seal.

I suppose the trick in setting this up is finding 2 plastic tube sizes such that one fits inside the other, so you can just attach the bag to the second tank's out-tube.

stevea@XXX.edu

I have done this. The idea is to bubble the offending mixture, containing a water-INsoluble gas which you DO want to keep as well as a somewhat soluble gas (SO2) which you DO NOT want to keep, through a very basic (high pH) solution.

Baking soda might work as the alkaline agent; I'm not sure. We used to use lye which does work quite well. Our assembly consisted of four PVC tubes about 36" high, each with about 6" of water in the bottom. The final stage did not contain any lye, in order to avoid introducing caustics into the delicate machinery downstream of this plant. ;-)

I learned quite a bit about handling compressed gases during this ordeal. I hope the following is too obvious to mention, but it wasn't for us and several of us could have been killed but for good luck. USE A F***ING PRESSURE REGULATOR UPSTREAM OF THE SEPARATION COLUMNS OR AT SOME POINT YOU WILL HAVE A PARTY ROOM FULL OF _SHRAPNEL_.

wickham@XXX.com

And a contributed note about lye:

Next point, the lye solution will cause nasty, slow, deep, long term
chemical burns to the skin and will destroy (blindness!) eye tissue.
However, it acts slowly so the person doesn't realize that it is happening
until it is too late.  If it is spilled immediately rinse with tons of water and
get the person to the hospital.  Lye is used as a drain cleaner and opener
(old Liquid Plumber Crystals) so that would be your excuse for
emergency room treatment.