12-16-02 00:51
No 389796
I am trying to tighten up and document the device and instructions that I am using to produce anhydrous NH3, but I have an idea that might simplify one aspect of the system. But I don't want to delay posting the current method unless it looks to make a real difference...
Here is the situation.
The fert and NaOH are added to a reaction chamber dry, which keeps them from reacting to any noticable degree. I then trickle in h2o to trigger the reaction of the strong base stealing from the week base and liberating NH3. However, the h2o absorbes an enourmous volume of NH3. In fact it will reobsorbe all the NH3 produced if given enough time and contact. In some early designs I would initially get a half cup of condensed NH3, which would then dissappear once the NH3 vapor prodution rate fell below the rate of absorbtion.
The rate of absorbtion is loosely determined by vapor consentration, surface area, pressure, concentration of NH3 already in the water, pressure and temp. What I have currently done to cap my NH3 loss is use a couple of one-way-vavles to pull air back into the reaction chamber instead of NH3 when it goes into suckback mode. This does have the unfortunate side affect of 'back-pressure' in the 1/2psi range between the reaction chamber and dryer/precooler/condenser.
This backpressure and the physical restriction of flow increases the pressure in the reaction chamber which increases absorbtion, lowers the presser in the condenser which slows condensation and gernerally slows the flow of the vapor out of the reaction chamber where it is in danger of being eaten instead of quickly hurrying on to the condenser where it will provide drugs for the needy.
Now even with the downsides listed, output with the one way valves is far greater than without, but I am hoping for better if possible.
I have two idea's which might offer better solutions, so maybe the wiser bee's can steer me to the more probabale option or save me two dissapointments.
1) Use a lighter than water solvent layer above the reaction to limit the 'contact' between the h2o and NH3 vapor. In my mind the vapor would bubble through the right solvent and then be blocked from the thirsty hydro. This of course assumes the existance and availability of a solvent that is less dense than h20, does not react with any of the participants and does not absorbe NH3. Does such a solvent exist? And what else should I consider?
2) Flow a stream of dry CO2 throughh the reaction chamber which would increase the flow rate of the NH3 out of the reaction chamber and decrease the consentration of the NH3 in contact with the water. This would also provide a non-condensing gas flowing thru the system making it practical to condense the NH3 inside of a small cross section heat exchanger without worrying about liqued blocking up the flow. The CO2 would propell the dropless through whereas 100% NH3 could just fill up the tube with liquid until the friction and inertia won out.
So this method has additional advantages, but wouldn't seem to provide as complete a solution as the solvent might, if it worked perfectly. But this method does increase the part count to some degree, but since I already use dryice to provide the cooling for the final condenser, I have a handy source for the CO2. Would this work, or am I just shadow boxing?
Finally, I could combin both methods, geting increased flow and reduced NH3/h20 contact and eliminate absobtion losses and gain the advantage of condensing the NH3 within the condenser tube, which is quicker than through the walls of the collection chamber as I am currently doing.
Any advice is appreciated!
TrickE
And on the eight day, God created Meth...
... and hasn't done much of anything usefull since!
(Hive Bee)
12-17-02 11:04
No 390181
Well, either I've stumped everyone or my spelling is much worse than usual.
So I'll add another question to those that already languish.
Is it possible to get the NaOH and Ammonia sulfate to react without the H20? Could another solvent or another base be used that wouldn't absorbe the vapor or at least less of it or at a slower rate?
I have worked past this problem sufficient to make it a practical option, but the quanitity of final product and care required in monitoring would be improved a good bit if your didn't have to 'push' the reaction so hard to get a reasonable percentage of the NH3 past the one way vavle before its taken up by the 'aquious insidious'. Even that wouldn't be too big an issue, if you didn't then have to be able to cool and condense the NH3 at an equal pace without building too much pressure and have to vent the excess to your acid trap.
Any help here, would like, um... help. Or something.
TrickE
And on the eight day, God created Meth...
... and hasn't done much of anything usefull since!
(Moderator)
12-17-02 12:56
No 390199
The method that's been used for many years to generate ammonia gas is to heat a dry mixture of ammonium sulphate and calcium oxide, then dry the ammonia using a tower packed with sodium hydroxide, why introduce water into the system when you're trying to generate anhydrous gas?
(Hive Bee)
12-17-02 14:27
No 390210
Well I gues I had better go move my 40lb bag of ammonia sulfate off of the 40lb bag of hydrated lime that its been stacked on top of for the last five months.
But I think I'll go light a candle first, uh two maybe.
I only found a single post on the subject, but it looks pretty good.
[Post 28411 (whatsupium: "NH3 variation", Stimulants)
They are both using a bit of h20, but mr clean advises using very little. Would you agree with his ratio's? And how hot to you think I need to get the reaction to get good results?
They mention that they were getting 200ml and 800ml in a few hours... seemingly with a superior chemical process than my own. But I have gotten two cups in less than an hour, no Bullshit. I didn't figure that was very extraordinary, but maybe I was doing better than I thought. I was however, using a 2.5 gal water bottle as the reactoin chamber. This will obviously not due for a heated reaction, so I'll have to ponder that a bit.
Thanks for your help, me and my neighbors appreciate the insight.
TrickE
And on the eight day, God created Meth...
... and hasn't done much of anything usefull since!
(Moderator)
12-17-02 14:49
No 390217
Post 207050 (lugh: "Re: Ammonia", Chemistry Discourse) & Post 201981 (lugh: "Cyanide Synthesis", Chemicals & Equipment)
(Hive Bee)
12-17-02 15:56
No 390229
Great, much thanks. I wonder why those didn't come up...
A couple of things which wasn't covered is the temp rang and overall reaction time or the amount of product achieved. Have you used this process, please tell.
TrickE
And on the eight day, God created Meth...
... and hasn't done much of anything usefull since!
(Moderator)
12-17-02 23:20
No 390319
Have you used this process, please tell.
No, it's much easier to buy a tank if that's what's needed, that's for sure 
The pictures show a Bunsen burner being used, so one would would imagine that a lot of heat is needed If you want to learn anymore before doing it, you'll have to read the reference given in that thread
(Hive Bee)
12-18-02 09:12
No 390465
Missed the sources, my bad. I will try to get ahold of them a post them if possible.
I am interested in this, and appreciate your help.
TrickE
And on the eight day, God created Meth...
... and hasn't done much of anything usefull since!
(Pioneer Researcher)
12-18-02 18:35
No 390540
Years ago I made ammonium formate for a Leuckart P2P rxn by dropping a solution of am. sulfate into a solution of NaOH, then passing it through solid NaOH (and then to formic acid). I don't remember if it was the aq. am. sulfate over the aq. NaOH or the NaOH over the sulfate...
Other method I tried recently and that works fine is to drop 25 % aq NH3 over NaOH, then pass the gas through solid NaOH, but both them are probably good only for kitchen amounts.