N2O refill

[Guest Monkey Shines]

If I had an empty gass cylider of N2O where could I get it refilled, BOC maybe, and would i need a licence or just a drivers licence?

[waterdragon]

normally BOC prefer to have you on a cylinder holders register so you can be hit with an annual fee. this applies to oxy acetylene setups so i guess it may also be the case for nitrous. some auto shops may do refills but i heard they added something foul to the mix, anyone?

[Pablo]

sulphur? i think there is a way you could try to filter all the bad stuff out but fucked if i could be bothered trying

[Guest Monkey Shines]

The auto shops add a small amount of hydrogen sulphide to make it smell bad like rotten egg. I think ill just ring them up and see.

[Torsten]

hydrogen sulphide is also an extremely poisonous nervegas.

Medical nitrous requires a prescription.

There is also a jewellery soldering grade, which may not contain the sulphide....

[bloodbob]

Hmm 2NaOH in H2O + H2S -> NaS + 2H2O

[Auxin]

"2NaOH in H2O + H2S -> NaS + 2H2O"

Ahhh, somebody knows about gass scrubbers.

But its more like:

6NaOH (aq) + H2S -> Na2S + 2H2O + 4NaOH

You need a little excess NaOH to keep the NaS from decomposing in a reverse reaction.

Then you need more excess in order for the reaction to work faster and more completely.

Its a simple reaction but setting up the equiptment might be out of most peoples league. Either you would have to have the gass recirculate through the scrubbing solution many, many times, or you would have to circulate it VERY slowly through many. Then of course you would have to send it through a gass drying cartrage, test it for H2S, and recompress it into a clean container. All without blowing your self up or suffocating to death in an unconcious stupor. Its probably easier to make your own instead of trying to purify the poison out of commercial stuff.

[This message has been edited by Auxin (edited 12 October 2002).]

[bloodbob]

yeah I forgot the 2 and you got stuff on both sides I dunno why. You don't have to worry about the a excess of NaOH cause we are probably talking parts per billion of H2S in the gas you want it reasonable concentrated so it reacts near to completion ( increasing concentration generally increase reaction speed ).

[Auxin]

You have to use excess, because you probably wont know just how much H2S is there to start with and if there is no excess not only will it go ultra slow but a reverse reaction will occur putting H2S BACK IN the gas.

TLV (Threshhold Limit Value) for H2S is 10 ppm in air, get it below that and it won't be toxic and will only stink a little.