Sciencemadness Discussion Board

pressure chamber

shadow - 3-7-2008 at 03:29

I have 2 pressure chambers.
The first one has about 50 psi of 3 gases let into it.
At a certain temperature, 2 of the gases I expect to liquify, leaving the one gas in the gas state which will then be let out of the tank at 1 or 2 psi into the second tank which is chilled below the boiling point of the gas.
Can I expect this gas to liquify, or am I going to just have some cold vapor?

Saerynide - 3-7-2008 at 05:33

Instead of letting out the remaining gas, why not drain the liquid from the bottom, leaving you with the gas in the chamber?

That way, you will have a much cleaner separation, as you won't risk having air enter the chamber and mixing with your stuff, and if you remove the gas first, you are creating a vacuum and that could cause your liquid to vaporize.

As for would you get cold vapor or liquid, it's not possible to say with so little information. That depends on the pressure, the temperature and the substance.

[Edited on 7/3/2008 by Saerynide]

F2Chemist - 3-7-2008 at 07:11

Totally agree with Saerynide. If you try to let the non-condensed gas out into the second tank, as you do so you'll lower the pressure in your system and the liquid in that system will vaporize, thus your seperation will be crap.

shadow - 3-7-2008 at 16:44

I had to go to work and didn't have time to detail the process quite correctly.
The first tank has continually incoming gases at approximately 50 psi. Yes, it could be shut off, but I'm looking for a continual process.
The pressure in the first tank is regulated down to about 1 or 2 psi( the pressure remains the same in the first tank), to flow low pressure gas into the second cooler tank hoping to condense it to liquid, and drain the liquid out the bottom.
The first tank will also be drained periodically.
I'm not specific about the gases because I know the first 2 liquify at room temp and the third at under 40C, and won't know more until the tanks are completed with the pressure guages installed.

MagicJigPipe - 6-7-2008 at 15:15

Why not just tell us what the gases are? It would be so much easier to provide correct information if we knew what they were.

Even if you separate the gases, how are you going to use them for anything if you don't know what they are?

Do they have a smell?
Color?
Density?
Boiling points (1 ATM)?

So?

shadow - 8-7-2008 at 03:41

Oh, well.
I was trying to keep it a secret.

I'm trying to improve on len1's ether extraction from starting fluid.

There is a bit of loss from evaporation as the fluid/gases are expelled from the can.

When released slowly, its virtually all gas. Released quickly, vapor and gas.

The gases are hexane, heptane, and diethyl ether.

I haven't found out what the can pressure is so I don't know what temperature the first tank will be heated to(if at all).

I could actually regulate the can gas into the first tank at any level I require.

As of now, I'm using a long pvc pipe with one end stuffed with glass wool to collect the hexane and heptane, but I don't open a valve I have on the can much, because I don't feel like exposing the weak system to much pressure.

The liquid collected probably has some ether in it.

I like Saerynide's idea of filling and draining only one tank. but then I still have to cool and depressurize the ether.

If I regulate the ether gas into a second cold tank at low pressure, I hope to liquify and drain it.
Your thoughts?

[Edited on 8-7-2008 by shadow]

[Edited on 8-7-2008 by shadow]