The Hive > Novel Discourse
Novel NH3 separation?
dwarfer:
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This simple cyclical set up was in my mind this morning as a
completed deal:
It is an elaboration of what was being grasped at in earlier communications.
Two idential ehrinmyers in buckets:
The one on the right in salted ice
The one on the left in dry iced alcohol, and a few ML of alcohol inside too. (To effect heat transfer for the first arriving gasses)
the one on the right gets it's aqueous ammonia air-bubbled (sparging):
because of the vapor pressure differentials (between water and ammonia at -5C) the ammonia/air mixture is selectively pulled from solution and bubbled (in the left hand ehrlinmyer) through the alcohol and then, as it accumulates, ammonia itself:
What to do with the exit from THIS flask?
Why plumb it back into the entrance to the pump.
Many cheapo aquarium pumps have this in and out feature: although the diaphrams may have a short life.
There are also "peristalic" pumps that do a rolling squeeze on flexible tubing:
although the tubing may not be to happy being squeezd at lower temperatures.
But that is a "build" problem: this is still design.
I'll bet a quarter kneejoint ":<) this will work:
I think that one pass will make the NH3 useable.
If not, the left hand flask once full
Can be put back in the right hand position
And the process re-done.
(Or, an identical flask to the left hand one can be placed in series.....)
=========================
The "end point" or diminishing returns will be noted in the right hand flask when ice crystals
start forming: this will mean the freezeing point depression of the NH3 is waning.
Imagine doing this:
You set it up with plenty of ice, both wet and dry ":<)
Let it run:
You take a nap
eat dinner
lay your wife or main squeeze
drink a beer or two or six
wander back out when you feel like it.
Contrasted with:
hangovers from too much smelling of salt fumes
arduous shaking of the reaction chamber with fertilizer and bases.
intense watching of the proces to make sure nothing untoward ocurrs.
lifting bending and chemical hazards
==========
I'll endeavor to find vapor pressures at -5C or so to figure out what % will be going over in "first
pass"
I'll bet a nickle it will be 90% one pass, but I'm not positive..
So it takes 3 passes?
BFD.....
dwarfer
===============
If the erudite denizens of this adventuresome forum would please critique this it would be appreciated.
dwarfer:
FINALLY a project Osmium can do:
NO GLUE!
YEA!
Osmium:
BIG brain fart dwarfer!
From the right flask you remove a (hypothetical) 90:10 mixture of NH3:H2O. This vapor is sucked to the left flask where it condenses because it is quite cold in there. Since NH3 has a higher vapour pressure than H2O you now pump almost pure NH3 back into the right flask, while the H2O stays frozen in the left flask. The NH3 concentration will rise in the right one, not in the left flask, until a steady state is reached and both flasks will be in equilibrium. Maybe you can hook up a few of them to reach a sufficient theoretical plate number, but I doubt it.
Of course it all depends on vapour pressures, I will try to find some numbers for your futile experiment.
dwarfer:
Damn OS: You gotta quit talkin' wit' dat' texas drawl: peeple 'l think you are FROM there, dontchaknow. 8)
=============
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I MIGHT be in error because of ionic bonding in flask de la right:
maybe the vapor pressures of the two molecules are not separable.
BUT since my understanding is that there is NH3 AND NH4-OH, there might be a chance that it would work.
On the other hand, if your theory is true, I would see no advantage in keeping the right hand flask cold at all: and I probably would return to my pipe lined bucket and condense ice inside the 1/2 inch tubes: certainly there is a ton more surface area for ice to condense on.
Either way, I appreciate your opinion, although I hope you are wrong.
"DISILLUSIONMENT IS A POSITIVE STATE OF BEING"
The alternative of course being IN illusion. ::)
dwarfer
Osmium:
Vapor pressure of ice:
0°C........................6.1129mbar
-5°C.......................4.02mbar
-10°C.....................2.60mbar
-20°C.....................1.03mbar
-30°C.....................0.38mbar
-40°C.....................0.13mbar
-50°C.....................0.039mbar
-60°C.....................0.011mbar
-70°C.....................0.003mbar
-80°C.....................0.001mbar
Sublimation/vapor pressures:
A)H2O
T/K..............................P/Pa
190..............................0.032(solid)
210..............................0.702s
225..............................4.942s
240..............................27.28s
250..............................76.04s
260..............................195.8s
270..............................470.1s
273.15..........................611.66s
B)NH3
T/K..............................P/kPa
160..............................0.1(solid)
170..............................0.4s
180..............................1.2s
190..............................3.5s
195.4............................6.12s
200..............................8.7
210..............................17.9
220..............................34.1
230..............................60.8
240..............................103
250..............................165
260..............................256
270..............................381
280..............................552
290..............................774
300..............................1062
1kPa = 7.50062 Torr
100kPa = 1000hPa = 1000 mbar = 1 bar
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