Sciencemadness Discussion Board - Birkeland-Eyde reactor for making nitric acid.

Birkeland-Eyde reactor for making nitric acid.

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axehandle - 11-2-2004 at 23:16

I'm constructing one, and have made a web page which documents my progress and is continously updated.

Comments, critizism, suggestions, questions etcetera are most welcome.

http://species8472.dyndns.org/no2/no2.html

axehandle - 12-2-2004 at 08:05

22 views, lots in the weblog, but no replies. I guess I'm the 1st one attempting this then. I'll let you all know how it goes.

Beating me to it, eh?

Turel - 12-2-2004 at 08:17

I'm constructing one as well, albeit a bit different than the one featured in that link.

I was not going to mention anything until it was done and successful, but you have beat me to it. So to answer your question, I suppose you are the first here to fabricate your own reactor, but not the first to consider and design one.

-T

[Edited on 12-2-2004 by Turel]

axehandle - 12-2-2004 at 08:24

Heh. Are yours more sophisticated than mine (e.g. using magnetic fields and DC arcs to form an oval arc)? In that case let's call it a draw.

Seriously though, how's yours constructed?

Edit: I think we could both benefit from a mutual exchange of design information to optimize our yields. The patent has expired long since....

This is my 6th reactor, all the previous ones have been made of glass and failed due to thermal stress; the 5th one actually employed watercooled hollow electrodes(which failed because of the conductivity of condensed water). This is the first one that actually seems to work, albeit I'll probably have to run it in 15 minute cycles for cooling reasons (15 minutes NST on, 15 minutes NST off, etc).

Regards,
/A

[Edited on 2004-2-12 by axehandle]

No magnets.

Turel - 12-2-2004 at 08:36

I was surprised to see the Jacob's Ladder-like arc in your reactor. I thought I was the first to decide to employ a travelling arc.

Air is passed through a widening travelling arc much like yours, only larger. The air is introduced into a closed vessel that encompases the arc, in the shape of a hand fan. It is introduced at the narrow end, so that as it expands over the increasing width, it slows and repeated arc exposure is forced.

The outputted gas stream is combined with a small warm oxygen stream, which pass through a condenser to draw out any formed NO2 as N2O4 for collection. The gas stream is then recirculated back through the arc for a repeated pass.

I am thinking of including an oxygen sensor or two in the line, to monitor O2 content of the airstream at the start of the reaction, and also at the condenser. I have NO2 sensors post condenser to make sure that no NO2 escapes condensation and reenters the initial reacting chamber.

The reaction of NO2 and H2O is performed in a seperate apparatus, and utilizes a cupric nitrate catalyst in the water solution. NO2 and Oxygen are bubbled through a fine atomizer at the bottom of the solution bath, which is stirred gently.

I am still constructing my apparatus, and working out exactly what power specifications to use for the arc.

-T

axehandle - 12-2-2004 at 08:49

Then you beat me. My setup is much simpler.

However, forget the oxygen stream. O3 is produced in the arc as well, giving an ample supply of O.

I've also been thinking about repeated passes, but concluded that the same can be achieved by a low air pass-through rate.

But I still considered myself beaten. Your design is much better, albeit it's only in the theoretical stage.

If you want some advice, I would say: The fewer parts, the better. That has been my experience during my experiments with the previous 5 failed rectors.

Who cares if the yield is e.g 50% or 100%? Electricity is cheap, I've plenty of both nuclear and water power available here...

But let's see who's design works best, shall we? What's your estimated time to completion of the apparatus?

Quote from you:
"I thought I was the first to decide to employ a travelling arc."

My reply: The more air exposed to the plasma, the larger the yield, and great minds think alike...

You wanted power requirements. I actually think that my NST it a bit too much. Dissipating 540W of power ain't easy. If I were you, I would stay at the same voltage as mine (9kV) but use an NST of lower power.

[Edited on 2004-2-12 by axehandle]

[Edited on 2004-2-12 by axehandle]

[Edited on 2004-2-12 by axehandle]

I Care! (kidding, kidding)

Turel - 12-2-2004 at 09:03

Agreed, 50% would actually be a fabulous yield in my opinion, since I don't pay for electricity at all. (grin)

But I do care that it works, and works reliably. The ideal construction would be a small size unit that can be used in continuous unmonitored operation for say 5 days or so. Throughput is not important, but reliability/stability and it working to begin with are.

This is more than a 'gee it would be cool' project; I originally started on this because of a need for relatively pure HNO3, and extended use of it; say 500mL/week reliably.

The reason for having the two reactions seperated is because when NO2 reacts with water it does not produce clean HNO3. Rather it begins to produce a mixture of HNO3 and HNO2. As the HNO3/H2O concentration increases, some of the HNO2 is oxidized, destroying both HNO3 and HNO2 in favor is solvated oxides, and other side reactions I am sure.

The cupric nitrate acts as an oxidation catalyst, mediating the oxidation of HNO2 with O2. Cu+2 ion oxidizes nitrite ion to nitrogen dioxide, which reacts with water in the way we are familiar. The oxygen oxidizes the formed cuprous ion, and lends itself to the creation of water, which quantitatively is consumed by the induced reaction of the formed NO2 with water. It all balances out to help HNO2 oxidize to HNO3.

For air, the oxygen content is only ~20% or so, and the arc favors NO production over O3, so I would assume that very little O3 is produced. O3 is favored by lower temperature arcs, and the arc you showed is quite plasmatic.

Have you tested your output gas for O3? Have you successfully produced NO2? I have not begun testing yet myself. If you need NO2 sensors let me know.

axehandle - 12-2-2004 at 09:11

My design is made to run 24/7.

My reason for building it is that purchase of acids are restricted in my country.

No, heven't tested for O3 (apart from nasal examination =), but I constructed a prototype and made 20cc of nitric acid which I "tested" by tasting it. It was the most acidic, vicious thing I've ever tasted.

Edit: tested with litmus paper as well, turned bright red instantly

I would be very interested in NO2 sensors, provided they can detect concentration as well as presence.

[Edited on 2004-2-12 by axehandle]

Congratulations

Turel - 12-2-2004 at 09:20

Im happy to hear that you were successful.

How long did it take you to produce that 20cc?

And no, actually the sensors will only detect the presence of NO2, and to not show a concentration.

axehandle - 12-2-2004 at 09:22

It took about 20 minutes. I have absolutely no idea what concentration i got though. But The spot on my tongue where I tasted a drop turned yellow, which is a good sign I suppose =)

Edit: I suppose this would be a sign of N2O4 produced in the arc, which is very good. I don't want to spend the money required for an oxygen tank.

Edit: Perhaps a REALLY hot arc, like mine, produces N2O4 in significant quantities? I don't know.

Edit: I'm running the reactor now, using a 15minute resolution timer (15min on, 15min to cool). Seems to work so far, no leaks anyway. I'll know when i taste the product =)

[Edited on 2004-2-12 by axehandle]

[Edited on 2004-2-12 by axehandle]

[Edited on 2004-2-12 by axehandle]

Wow, I am really impressed.

Hermes_Trismegistus - 12-2-2004 at 19:43

with everything except the "taste test"

perhaps you could just titrate (until neutral) a known concentration of either NaOH or even (ghetto prep) a known amount of a commercial antacid tablet/s to find out the HNO3 concentration.

Then extrapolate time v.s. production.

WoW!

axehandle - 12-2-2004 at 20:35

Thank you.

The taste test was due to naïvete...... I couldn't imagine that such a short run would work.

Pity I don't have a titration thingy, you know what I mean, the one with a lever and lines indicating volume. I don't even have a scale capable of more than +/- 1 g resolution. I'll have to buy lots of equipment, and right now I'm low on cash due to my recent platinum wire order.

But I _will_ measure the density and compare it to a chart I found here on the board. That will only take a large accurate
volume measurement thingy (what the hell are those called in English anyway?) + my scale.

Right now though, I'm going to construct a larger reactor (bigger clay pots...) to get rid of the heating problem that forces me to use a 50% duty cycle. Then I can run 24/7!

[Edited on 2004-2-13 by axehandle]

Awesome!

Tacho - 13-2-2004 at 02:43

This is the most impressive thing I have read in this forum lately. It could turn out to be a simple way to provide HNO3 to the amateur lab.

axehandle, your design is better than good: it's done! Just don't taste it anymore ok?

I have made an ozone gererator that used a flyback (tv) transformer and ONE pnp transistor, plus a couple of components. It is rather simple, the spark is long but not very strong due to low wattage. The advantage is that the only thing that really heats up is the transistor.

I would be glad to give you details if you think it could help.

Keep us informed.

axehandle - 13-2-2004 at 03:21

Well thank you! That takes some of the frustration of building 5 non-working reactors before this one away.

But my design is NOT better than good. I'm going to do some improvements today:

1) Using larger pots to allow for continous running by eliminating the heat problem. This also allows for longer steel rods, exposing more air to the arc.

Edit: I got a pair directly from IKEA, very nice (and EXPENSIVE) pots..... $7 each sigh.

2) Connecting 2 small lengths of PVC hose to the glass pipe at the bottom of the bubblers, each with 40 1.5mm holes drilled along their lengths to increase gas mix to water exposure.

Edit: Done, let's see the result.

3) Construct a new jacob's ladder, which starts with a small gap at the bottom, then expands, then contracts again to form a small gap at the top. This is cosmetic: Every time the arc breaks at the top of my current construction, it seems radio waves are generated, making these incredibly annoying clicking sounds in my loudspeakers. This doesn't happen as long as the arc is "on".

Edit: Rethought. That model would require air to be injected from both ends with the reactor being aligned horizontally. I've decided to go for a more conventional approach, with a V shaped jacob's ladder. I procured a 1m long 8mm thick so-called silver-steel rod today. Cost me $18 sigh.

4) Move the apparatus to the kitchen. The pumps are very loud. Or perhaps just moving the pumps to the kitchen and use a long hose.

5) Increase the length of the PVC hose connecting the reactor to the first bubbler, giving the NO longer time to become NO2. The air flow is a bit fast, but until my next reactor it has to be for cooling reasons.

6) Perhaps add a third bubbler. Those airtight food glass jars cost only about $3 each.

About the ozone: I think my spark already generates some of it.

And I will keep you all informed. I'll update the web page for every step.

Tasting it? Never again. I just recently dipped a blue litmus paper into the first bubbler. It turned red. VICTORY!

But as I said, I'm going to make improvements.

As you said, it could turn out to be a way of supplying nitric acid to the amateur lab. The only caveat is that the NST was quite expensive (approx. $200). But it will probably outlive me...

Edit: I've been thinking about getting a second NST and make a device made up of 2 jacob's ladders aligned 90 degrees to each other, but since my cash flow is right now negative, that will have to wait...

I looked into flyback transformers when I started research for this project. As it turned out, they were impossible to buy, and I had/have no TV (don't watch TV) to dissect..... so I decided to go the whole way and buy a new NST with high power ratings.

[Edited on 2004-2-13 by axehandle]

[Edited on 2004-2-13 by axehandle]

[Edited on 2004-2-13 by axehandle]

Also

Turel - 13-2-2004 at 12:50

I totally forgot to ask. What color was your produced acid specimen?

axehandle - 13-2-2004 at 13:45

Completely transparent.

Saerynide - 13-2-2004 at 17:11

I thought nitric acid was yellow

EDIT: WOW. What you did was amazing

[Edited on 14-2-2004 by Saerynide]

axehandle - 13-2-2004 at 19:13

Actually the color was hard to tell when the amount produced consisted of some liquid on the bottom of a large vessel, the glass thereoff being not completelety colorless in itself, el cheapo as it is.

Nitric acid is only yellow if it has unreacted NO2 dissolved in it, btw.

It was definitely a very strong acid, though.

Edit: The magical nitric acid machine, which I've been left running overnight, has a color in the first bubbler. I just can't say which, since I'm colorblind. Not a serious handicap, but I need a multimeter to sort resistors....

Edit: Btw, I changed the duty cycle to 30mins on, 15mins off, etc. The silicone stands up to this remarkably well.

Edit: It's Casco brand, and called "glassilikon".

[Edited on 2004-2-14 by axehandle]

[Edited on 2004-2-14 by axehandle]

[Edited on 2004-2-14 by axehandle]

[Edited on 2004-2-14 by axehandle]

[Edited on 2004-2-14 by axehandle]

axehandle - 14-2-2004 at 00:28

Thank you Saerynide. But there's nothing really amazing about it. When researching different methods of producing nitric acid à la Google, I stumbled across the name of a Norwegian named Birkeland.

A quick search of the USPTO database listed several patents regarding a plasma arc device for making nitric acid out of air and electricity.

After reading them, I said to myself: "I can do this", and then I proceeded doing it. Nothing ingenious about it, just a lot of persistance really.

Edit: Although there was _some_ science involved....

[Edited on 2004-2-14 by axehandle]

axehandle - 14-2-2004 at 01:18

Comments so far: It seems that the NO needs some time to become NO2, which is proven by the fast that the liquid in the second bubbler is more acidic than that in the first bubbler.

Hence I'm going to insert an empty "delay" bottle before the first bubbler. Gas / NO mixture will enter at the bottom and exit at the top.

I've also aquired two clay pots with a height of approx. 30cm and a diameter of about 20cm.

I've also aquired two new electrodes, both 50cm long, both of which I intend to place in a more conventional jacob's ladder configuration, with a 2 degree separation. Apart from this, I see no reason to change the reactor design. I might install a small feedback loop from the delay bottle to the reactor to increase the NO2 formation though.

I also intend to place the reactor inside a Faraday cage to get rid of the radio emissions. I just have to find a steel net of a sufficiently largel mesh number.

Edit: Ah, yes, I also intend to "build in" the probe of a digital steak thermometer in the reactor, to monitor the temperature.

Edit: I wonder if it's things like this that make my friends (the few I have) call me "McGyver"..............

[Edited on 2004-2-14 by axehandle]

[Edited on 2004-2-14 by axehandle]

axehandle - 14-2-2004 at 05:24

Comments on the new design (no pictures yet, I want the silicone to harden before moving the damned thing) are available at http://species8472.dyndns.org/no2/no2_2.html

in case you're all interested.

axehandle - 14-2-2004 at 05:31

I wonder who it it that keeps visiting my site using "windows 98". Windows 98 is a complete dungheap...... even compared to the other MS "operating systems", bar one: Millenium edition. That one is actually worse, believe it or not.

leopard - 14-2-2004 at 06:13

Axehandle this subject is also discussed in another thread "Alternative Method for HNO3 Synthesis". In this thread I briefly describe my experience with this method of producing Nitric Acid. Though my apparatus was very crude I was impressed with the results. Within minutes of running my setup the second jar filled with brown/red NO2 and within 20 hours I had about 50ml of Nitric Acid which yielded a heaping tablespoon of Urea Nitrate. The nice thing was the fact that it could run unattended. I performed this test in my garage and there was always a strong smell of NO2. Be carefull !! Good luck.

axehandle - 14-2-2004 at 06:16

Thank you, and I will.

Edit: I still think my lovely reactor deserves an own thread though........ =)

Edit: New reactor has concrete hardening in both top and bottom. Have to wait at least 24 hours b4 dehydrating the bottom sigh...............

[Edited on 2004-2-14 by axehandle]

[Edited on 2004-2-14 by axehandle]

Dammnit JIM! I can't read code! I'm a madscientist!, Not a computer programmer!!!

Hermes_Trismegistus - 14-2-2004 at 10:43

axehandle - 15-2-2004 at 23:22

Uh-uh. The new rector vessel with the elctodes doesn't fit in my oven, so I've placed in on the stove. This is going to take a while, I'm afraid, since the vessel has a rim along its edge, thereby having a very low contact area with the hotplate.....

I'll probably have to wait the whole day.

Luckily the conductivity of the concrete is within my multimetre's range, approx. 0,26Mohm. Have to get it down to 0....

BIG sigh.....

Edit maybe of I put in a textile bag with CaCL2.... hmm.

[Edited on 2004-2-16 by axehandle]

Quantum - 16-2-2004 at 08:39

Its not me! I run Slackware 9.1

Do you have information on the TV flyback? I have a few old TVs and I was wondering how those work compared to the NST.

GREAT Project. You could install a burret like thing in the bottom of the second jar and do a side reaction with some of the nitric acid.

axehandle - 16-2-2004 at 09:13

Not much info, apart from the fact that they don't put out nearly as much power as my NST.

Plus that it looked like such a pain to identify the different connectors that I considered it worth $200 just to avoid it.

There are sites,
http://www.geocities.com/CapeCanaveral/Lab/5322/hv2.html

is one, in case you really want to mess with flybacks.

Tacho - 16-2-2004 at 15:18

axehandle,

I'm in a hurry now and will be away for a couple of days, but can't you do titration with a common syringe and a solution of sodium bicarbonate? It is widely available and stops fizzing when all acid has reacted. I never tried this, but sounds simple. The only problem could be weighting the bicarbonate if you don't have a scale.

GAK!

Hermes_Trismegistus - 16-2-2004 at 17:57

antacids of all kinds are widely available, I had previously suggested this.

Convieniently enough, the amount of antacid per tablet is even written on the side.

you could use a periodic table to convert mass into moles (knew that thing would come in handy someday

)

With a syringe (or other measuring device), to measure the water it took to dissolve the tablet. Then you'd know th molarity of your base solution.

You would even be able to make up a solution of known concentration.

From that you could titrate the acid to neutrality and you'd know the concentration.

*** If you do a titration, you may need to dilute both your acid and base quite a bit to get even decently close to neutral.

If you need a cheap indicator solution, look in this thread...

http://www.sciencemadness.org/talk/viewthread.php?tid=1372

:cool:

EDIT: analytical chemistry is a necessary evil. Yes, I said it....EVIL.

[Edited on 17-2-2004 by Hermes_Trismegistus]

axehandle - 16-2-2004 at 23:14

Can't do a titration just yet, have troubles dehydrating the concrete in my new reactor (it won't fit in the oven...). But I will. In a week or perhaps two.

Edit: I hacksawed 5cm off of the electrodes. Now it fits in the oven. Phew!

I'll use antacid tablets, I think, with a large amount of acid since my scale has a resolution of +- 1g.

[Edited on 2004-2-17 by axehandle]

axehandle - 17-2-2004 at 07:33

Damned! The bottom concrete layer had too great a volume and was thus conductive. No arc. Have to redesign entire bottom (already done) and then wait another fscking 24 hours for the small amount of concrete to harden. If I only could get away with gypsym..... but I don't know how gypsum behaves at plasma temperatures. Fsck.

Edit: (18:59) Everything molded. I don't even want to see unmixed con-fucking-crete again as long as I live. Filty, dirty powder!

[Edited on 2004-2-17 by axehandle]

froot - 17-2-2004 at 07:44

arb question:
I've read that one can only get up to 70% conc. HNO3 when dissolving NOx in water, or that's how they mass produce it, after which they distill it with H2SO4 to get higher conc.
Could you get higher conc. when dissolving NOx in H2O2, or otherwise reacting NOx in a vessel with a precise amount of water vapour?

axehandle - 17-2-2004 at 08:51

I think the maximum is more like 68%. With regards to using hydrogen peroxide, I think
this reaction is favored:

NO2 + H2O2 --> HNO3 + OH-

The H3O+ OH- ions would cancel out,
H3O+ + OH- --> 2 H2O
.

The end result would be water. This is, however, by conjecture only. Perhaps someone else feels qualified to answer?

I also read somewhere (I think) that the 68% (70%?) limit is not the theoretical limit, but that it's not economical to make it stronger (takes much longer time and energy).

Tacho - 19-2-2004 at 04:40

About Hermes antiacid titration:

I really, really think that you should use sodium bicarbonate. It's sold pure, with no binders, medicines or flavors and IT IS IT'S OWN PH INDICATOR. It simply stops fizzing (bubbling) when all acid has reacted.

I sugested the syringe to measure how much solution of bicarbonate with KNOWN concentration would neutralize a given (small) sample of acid. A common syringe measures 10ml with 0,1ml precision.

Something else: Concrete gets hard because it HYDRATATES. When molecules of water bind to the portland cement, it gets hard. So, you will never get rid of all water unless you kind of destroy it. I have never seen concrete as an eletrical insulation. On the contrary, ceramic insulators are everywhere.

axehandle - 19-2-2004 at 06:29

Good idea, about the sodium bicarbonate.

About the concrete: I know that it gets hard because of hydration. I also know from empirical observation that if it's dried out, it WILL act as an insulator, unless it occupies a large volume (more current paths).

I also know that its compressive strength gets greatly reduced in the dehydrated state. Same with gypsum. It just has to be handled gently, and everything is fine. A sharp blow (impulse): *crack*

My new reactor bottom is right now in the oven. I used even less concrete than in my small, working reactor. It remains to be seen, however, whether the experiment is repeatable......

Otherwise, I'll try terracotta clay. Little cracking tendency. Hell, even dehydrated gypsum would do the trick, the material's only job is to hold the electrodes and to withstand hign temperatures.

The reason I haven't tried gypsum is that I suspect it would decompose at plasma arc temperatures. We're talking thousands of Kelvins here.

If it all pans out, I will start updating my webpage with shots of the new plasma arc. I will make an anouncement here first, though. My bandwidth is limited......

Marvin - 20-2-2004 at 06:13

It would be helpful if you read the nitric acid from arc threads here and on roguesci.

You are using a jacobs ladder becuase you think the arc moving through the air will provide greater contact. You havnt asked yourself *why* the arc rises though. The answer will alter your design though maybe not be much.

Dont think of it in terms of liberating free atoms or ions. You are driving an exothermic reaction backwards with high temperature, and then freezing it in. No ozone will be made this way.

If you dont concentrate the NO2 produced, you will be lucky to make 50% acid concentration, and in doing so your absorbtion will be very inefficiant.

NO2 is extremly toxic, you dont want to breathe any in.

"Who cares if the yield is e.g 50% or 100%"
Try thinking 2% on a power basis....

Half a kilowatt will only produce about 20 to 30 grams of acid an hour max. Its hardly worth building a system to produce less. This totally rules out a flyback transformer as power at about 1/100th this.

Only the arc should be hot.

axehandle - 20-2-2004 at 11:38

I know why the arc "rises". That's high school physics.

Before designing the machine, I evaluated a different method for the arc. Basically the arc is stationary, and air is pumped through it very fast, just like in one of the patents for the Birkeland-Eyde reactor.

I think I will stay with the ladder though. Have you any idea att all how much a stationary arc erodes and heats the electrodes? I have hands-on experience. What works in theory doesn't always work in practise. And no, my budget doesn't allow for tungsten electrodes...

I AM going to "recycle" some of the NO2 by feedback. This is on my homepage or in this thread somewhere.

And you have obviously not read about how I get rid of the fumes.

And what flyback? I'm using a 550W NST, 9kV, 60mA.

Btw, 20-30mg of acid per hour would be a fantastic yield, in my opinion. That's 5 liters/week!

I'm really confused, you obviously critizise my project, which is fine, but it also seems you do so without having studied the entire thread, or my setup, which is not fine.

What is your intent? To confuse me?

[Edited on 2004-2-20 by axehandle]

Tacho - 20-2-2004 at 11:49

Quote:

Originally posted by Marvin

(snip)
Half a kilowatt will only produce about 20 to 30 grams of acid an hour max. Its hardly worth building a system to produce less. This totally rules out a flyback transformer as power at about 1/100th this.

Only the arc should be hot.

You are righ about many things (edit), but:
1- I've built jacobs ladders using neon light transformers and using flybacks. Both created ozone smell. But flybacks probably can't make NO2: not enough energy.
2- 20 to 30 grams of acid for 0,5kW/h is a great yield for those who can't just buy it! I understand acid sales are limited in the country where axehandle lives, as it is in many others.

Besides, axehandle is probably having a great time building this stuff. I envy him.

Edit 2: By the way, he has BUILTED IT! MADE IT WORK!. I see a lot of talk in many forums but is rare when someone puts an idea to work!

[Edited on 20-2-2004 by Tacho]

[Edited on 20-2-2004 by Tacho]

axehandle - 20-2-2004 at 11:59

I still don't understand why he critizised my project when it was obvious he had not read all about it. E.g. I'm certainly not using a flyback. I'm using a VERY powerful NST.

And he didn't offer any constructive critizism at all. :mad:

Yes, nitric is restricted here, sulfuric as well. And I AM having a great time building this machine. Thanks for envying me =)

Tacho - 20-2-2004 at 12:05

I might stop envying you and start building one myself.

axehandle - 20-2-2004 at 15:24

I say: Go ahead! Plasma arcs are very fun to work with. The only drawback is that NSTs are so expensive, I paid $200 for mine. On the other hand it's short-circuit protected and completely cast into a resin block. The monster weighs 8kg....

Marvin - 21-2-2004 at 07:29

Maybe I'm not being clear. When I say 'helpful to read' I mean, 'read the threads because there is so much you dont know, I cant retype it all here'. Particually the stuff on roguesci.

"I know why the arc "rises". That's high school physics. "
Maybe you would like to explain why you think it will cause the arc to contact more air then?

"And what flyback? I'm using a 550W NST, 9kV, 60mA. "
Are you really? Well gee, I based all my math on your predicted yeild based on a half kilowatt system, so if Ive not read your posts that must make me, like, psychic or something. Possibly the flyback comment relates to your discussion with Quantum, and his questions? And your suggestion to Turel about using less power?

"...20-30mg of acid per hour would be a fantastic yield, in my opinion. That's 5 liters/week! "
20 to 30 grams an hour, and more like 3 litres a week of pure acid but the product will be somewhat dilute.

I have read the thread, and looked at the site and since you wanted people to point out mistakes/problems that is what I am endevering to do.

"I AM going to "recycle" some of the NO2 by feedback. "
No, dont do this, it would be bad.

You might want to take heed from the death of a NST in jacobs ladder config particually.

"What is your intent? To confuse me? "
Yes, of course. I cant let you make any nitric acid, you would use up all the air on the planet. I need this air for my own explosives.

axehandle - 21-2-2004 at 08:10

Quote:

Maybe I'm not being clear. When I say 'helpful to read' I mean, 'read the threads because there is so much you dont know, I cant retype it all here'. Particually the stuff on roguesci.

No, you were very unclear. Than you for being it now.

Quote:

"I know why the arc "rises". That's high school physics. "
Maybe you would like to explain why you think it will cause the arc to contact more air then?

Because the airflow through the reactor vessel is very slow, close to stand-still. Hence a moving arc will contact more of it in a given time.

Quote:

"And what flyback? I'm using a 550W NST, 9kV, 60mA. "
Are you really? Well gee, I based all my math on your predicted yeild based on a half kilowatt system, so if Ive not read your posts that must make me, like, psychic or something. Possibly the flyback comment relates to your discussion with Quantum, and his questions? And your suggestion to Turel about using less power?

If you had mentioned that, I wouldn't have jumped at your throat like I did. It looked like you were accusing me of using a flyback. You did not make any reference as to which posts you were referring to, thus I took is as being aimed at me --- all of it.

Quote:

"...20-30mg of acid per hour would be a fantastic yield, in my opinion. That's 5 liters/week! "
20 to 30 grams an hour, and more like 3 litres a week of pure acid but the product will be somewhat dilute.

I obviously meant "g", not "mg". Mistype. My calculation of the yield per week was 7*24*30/1000 liters. Dilute, ofcourse.

Quote:

I have read the thread, and looked at the site and since you wanted people to point out mistakes/problems that is what I am endevering to do.

Fine. Dandy. Very nice. But you were totally unclear on what you were critizising. It looked like a complete trashing of my entire design, and I get mad when someone says one of my children (e.g. my reactor) is ugly...

Quote:

"I AM going to "recycle" some of the NO2 by feedback. "
No, dont do this, it would be bad.

Why?

Quote:

You might want to take heed from the death of a NST in jacobs ladder config particually.

The company manufacturing this particular NST gave me their word that it would work in a jocob's ladder config.

Quote:

"What is your intent? To confuse me? "
Yes, of course. I cant let you make any nitric acid, you would use up all the air on the planet. I need this air for my own explosives.

I'm not intending to make explosives. I'm very afraid of explosives. I AM, however, very interested in rocket fuels.

[Edited on 2004-2-21 by axehandle]

If you can spare the time.....

Hermes_Trismegistus - 21-2-2004 at 11:40

We're all waiting to see the bigger reactor up and running.
So, if you can tear yourself away from your little lovers spat with starvin' marvin.....?

Tacho - 22-2-2004 at 02:07

Quote:

Originally posted by Hermes_Trismegistus
We're all waiting to see the bigger reactor up and running.
So, if you can tear yourself away from your little lovers spat with starvin' marvin.....?

Absolutely right!

This is becoming one of those endless pie fights that waste so much time and bandwidth in the net!

Axehandle, what you are doing is a great project!

Somebody has discussed it before? Cool, lets see what they did!

Someone treats you like you are an idiot? This is an anonymous forum! Swallow your pride, be artificially humble! Truth will surface with time.

Check the usenet! Is full of these no-win endless pie fights. Waste, waste, waste.

And focusing on the reactor: Even if the acid is not concentrated, is an easy, cheap source of nitrates!

rikkitikkitavi - 22-2-2004 at 02:47

nitric acid can easily be concentrated to 68 % by distillation at normal pressure...

glass, stainless steel is suitable materials of construction.

/rickard

axehandle - 22-2-2004 at 04:14

Quote:

If you can spare the time.....

We're all waiting to see the bigger reactor up and running.
So, if you can tear yourself away from your little lovers spat with starvin' marvin.....?

Yes, yes, impatient ones, I'ts just that I'm having some trouble with the clay. The ladder is functioning, but the clay holding it in place takes forever to dry.

I estimate that I'll have some pictures ready tonight (+10 hours from now), and then I'm going to assemble the bottom and the lid. It's got a very nice integrated digital thermometer. The glass/ceramics silicone will take approx. 24 hours to cure long enough to start running the reactor.

Better slow and working than quick and non-working, eh?

And I consider the "pie fight" over. In my opinion it was all based on a misunderstanding.

Edit: (00:23) The fucking evil bastard clay shit refuses to cooperate. Had to re-mold. Twice! If this doesn't work when it's dried, it's bentonite/distilled-H2O time..... Luckily, I have a couple of kgs of bentonite-W powder as well as distilled water.

It seems that as long as there's more than 1 water molecule in the insulator, it won't insulate. This is taking longer than I had hoped for.

At least I have glass-silicone-glued entrance and exit pipes to my 5 liter buffer reactor (where NO will get plenty of time to become NO2). Pity the silicone only hardens 1mm/24 hours sigh.

What a horrible day. I hate clay as well. On careful consideration, I hate everything. Fucking clay.

[Edited on 2004-2-22 by axehandle]

axehandle - 23-2-2004 at 15:41

The FINALLY functioning reactor bottom with the ladder is now in the oven to remove the last of the few remaining pesky water molecules from the gypsum (yep, gave up on the concrete). Time to completion: Approx. 10 hours.

The new arc was beautiful, a dazzling flaming white. I'll get some pictures up tomorrow.

I did a NO2 test by putting a large glass vessel upside down on top of the ladder and let it run for 20 seconds. Then I stuck my nose into it and took a deep breath. I shouldn't have done that. Suffice it to say that the ladder works....

Blind Angel - 23-2-2004 at 15:59

my god, you should really go to some bank to get help for paying more equipement, instead of tasting HNO3 or breathing NO2 to see if it's realy there, you'll kill you and this is not what we need

It's been explained to him......

Hermes_Trismegistus - 23-2-2004 at 22:44

how he could quantitatively measure the amount of acid produced by going out and getting a packet of rolaids and head of purple cabbage.

It seems he's just insane,

He's resourceful, intelligent and dedicated.....but utterly lacking in the sense God gave the common dog.

axehandle - 23-2-2004 at 23:45

Quote:

It's been explained to him......

how he could quantitatively measure the amount of acid produced by going out and getting a packet of rolaids and head of purple cabbage.
It seems he's just insane,

He's resourceful, intelligent and dedicated.....but utterly lacking in the sense God gave the common dog.

I do have litmus paper. Lots of it.

And come on, the gas wasn't even brown.....

Besides, human lungs can take a lot more than one would think. I feel fine. Honestly.

And having had 2 dogs, I can vouch for the fact that I do have at least some more common sense than a dog. And if sense is so common, why do we see so little of it?

Edit: Btw, the reactor bottom is cooling now. Once the oven hits 80C, I'll pick it out and take some shots.

Edit2: And I'm not suffering from insanity, I'm enjoying every minute of it!

[Edited on 2004-2-24 by axehandle]

[Edited on 2004-2-24 by axehandle]

[Edited on 2004-2-24 by axehandle]

Saerynide - 24-2-2004 at 01:45

Hahahaa.

But you really should treat your lungs with a bit more respect. I respect mine ALOT more now, after having gone through over a week of pain from HCl/Cl2 poisoning feeling like I continuously could not get enough air

EDIT: No, I was not disrespecting them before *cough* like axehandle *cough* (j/k j/k), it was an accident

[Edited on 24-2-2004 by Saerynide]

Site updated.

axehandle - 24-2-2004 at 02:09

NOW

The new page is under construction and there are some nice pictures *cough* *cough*.

http://species8472.dyndns.org/no2/no2_2.html

Quote:

But you really should treat your lungs with a bit more respect. I respect mine ALOT more now, after having gone through over a week of pain from HCl/Cl2 poisoning feeling like I continuously could not get enough air

I took the pictures with a window open. The smell of NO2 only allowed for 18 shots before I had to stop the reactor....

I respect my lungs much more now, I have seen how much of a beating they can take without killing me.

Seriously though, I've implemented some new security protocols:

1) Window open.

2) No sniffing.

3) No tasting.

4) No electrocution.

Edit: 5) No drinking of HNO3, even if dilute.

[Edited on 2004-2-24 by axehandle]

Marvin - 24-2-2004 at 05:39

"Besides, human lungs can take a lot more than one would think"

axehandle you are without doubt a fucking idiot.

Its very easy to get blase about NO2. Familiarity breeds complacency, particually when you havnt read the safety data.

You can breathe in NO2 and feel as if youve got away with it, normal, undamaged. Then 8 hours later, up to a day or two, you can drop dead of pulmonary edema. At lesser doses NO2 does largely unnoticed but long term damage to the rather fragile lung tissue. This is not simply caused by the acid NO2 forms as it dissolves with water, its a very reactive free radical - also why its paramagnetic and dark brown.

10+ years ago when I did my arc chamber/nitric acid experiments I didnt know this. MSDS sheets were not just a few clicks away, the information in the good books from the 40's was pretty lax on safety. I assumed a little NO2 in the air was no really bad thing and was a bit surprised one day after an accidental exposure I contracted chronic pneumonia, and which lasted long enough to give me a a decent scare. I thought, ok, what must have happened is that 'little bit' of NO2 knocked out the immune system in my lungs and I got an infection. I was completely wrong. What happens is the NO2 does so much damage in the lungs that the immune system assumes you have a major infection. It brings out the full 'pneumonia arsenal' to combat an infection that doesnt exist and for damage that was done up to days earlier.

Unfortunatly, the human body hasnt evolved to judge how nasty lab chemicals are, and since we dont know better we assume that some minor irritation in the mucus lining is just that. What you actually experience are just symptoms and we rely on our badly adapted biology to be giving us symptoms related to the damage being done by the gas so we can judge risk properly.

The thing about people that taste chemicals or test for high voltages with their fingers or hang around neer lit fuses, when everything goes fine people say 'hes, crazy' 'he must be insane' and then grin, and when things go wrong they say 'Oh shit, that was unlucky' or 'he shouldnt have done that' when what they really mean in both cases is 'what a fucking idiot'.

While in the long run it makes no difference if you kill yourself or when, there will be a lot of other people reading this thread that will assume you know what you are talking about. If you adopt a lax attitude to NO2, they will assume this is acceptable. It isnt.

"I know why the arc "rises". That's high school physics. "
Maybe you would like to explain why you think it will cause the arc to contact more air then?
"Because the airflow through the reactor vessel is very slow, close to stand-still. Hence a moving arc will contact more of it in a given time. "

Aparently high school physics is letting you down. An arc is a low conductivity path through the air, its low conductivity becuase its hot and (partially) ionised which the current maintains. Hot air rises becuase its less dense than the surrounding air and when it rises it pulls the arc with it since this is the path of least resistance. The arc is rising with the air, not through it. Trimming the ladder until the arc does not break solves a lot of problems, and combined with a static vertical magnetic field should increase yeild substantially (particually concentration in air making it easier to produce better nitric).

"I AM going to "recycle" some of the NO2 by feedback. "
No, dont do this, it would be bad.
"Why?"

Air passing into the arc comes out with a concentration of nitrogen oxides that does not depend on the amount going in. Its wasted NO2. Aditionally people seem to get better results if the air going into the arc chamber is dry.

You might want to take heed from the death of a NST in jacobs ladder config particually.
"The company manufacturing this particular NST gave me their word that it would work in a jocob's ladder config."

Read the thread on roguesci. While it will certainly work, how long it will live is more the question. I came to the conclusion that the constant sparking might well be generating fast voltage spikes (eg from inductive kick) that degraded the insulation over time. Its also possible it simply overheated from the neer short current.

"I'm not intending to make explosives. I'm very afraid of explosives. I AM, however, very interested in rocket fuels."

There is not so much of a difference. What fuel/oxidiser are you planning to make with the nitric acid?

For the record, I do not have a 'problem' with your project. I hope it succeeds. You are quite entitled to tread your own path, make your own mistakes and we will learn from it either way. I will try to help, you can listen to my suggestions or not, if something is covered well elsewhere I do reserve the right to simply point you to it rather than type it all in myself. If you state as facts things I know to be wrong I do reserve the right to correct them and last but by no means least, if you tell people things are safe when they arnt, if you tell people something is doing less damage to them than they think - when you havnt read the information and very particually when it relates to NO2 - then I do reserve the right to call you a fucking idiot.

axehandle - 24-2-2004 at 08:55

Quote:

"Besides, human lungs can take a lot more than one would think"

axehandle you are without doubt a fucking idiot.

Can you spell "humor" and "irony"?

Quote:

Its very easy to get blase about NO2. Familiarity breeds complacency, particually when you havnt read the safety data.

You can breathe in NO2 and feel as if youve got away with it, normal, undamaged. Then 8 hours later, up to a day or two, you can drop dead of pulmonary edema. At lesser doses NO2 does largely unnoticed but long term damage to the rather fragile lung tissue. This is not simply caused by the acid NO2 forms as it dissolves with water, its a very reactive free radical - also why its paramagnetic and dark brown.

Well, I've read up on it now, after a very nice person warned me without calling me "a fucking idiot". Apparently it is much more dangerous than I previously thought. I know that now. I'm not senile yet.

You might want to save on you "fucking idiot"s's. People tend to stop reading what you write after you start the childish name-calling.

[...snip...]

Quote:

The thing about people that taste chemicals or test for high voltages with their fingers or hang around neer lit fuses, when everything goes fine people say 'hes, crazy' 'he must be insane' and then grin, and when things go wrong they say 'Oh shit, that was unlucky' or 'he shouldnt have done that' when what they really mean in both cases is 'what a fucking idiot'.

I don't test for high voltages with my fingers, nor do I use fuses at all. I always (fior my rocket engine tests) use electrical ignition with a very long cable hooked up to an apparatus with TWO safety switches.

Nor will I ever "taste test" nitric acid again. Have you heard about learning from one's mistakes?

Quote:

While in the long run it makes no difference if you kill yourself or when, there will be a lot of other people reading this thread that will assume you know what you are talking about. If you adopt a lax attitude to NO2, they will assume this is acceptable. It isnt.

It's not my responsibility what other people think. And my "lax" attitude is part of my humor, which you obviously don't get. You must be a very boring person, OR there's something wrong with my humor.

[...snip...]

Quote:

Aparently high school physics is letting you down. An arc is a low conductivity path through the air, its low conductivity becuase its hot and (partially) ionised which the current maintains. Hot air rises becuase its less dense than the surrounding air and when it rises it pulls the arc with it since this is the path of least resistance. The arc is rising with the air, not through it. Trimming the ladder until the arc does not break solves a lot of problems, and combined with a static vertical magnetic field should increase yeild substantially (particually concentration in air making it easier to produce better nitric).

That's why the air is pumped in TANGENTIALLY, so that the arc will contact more (turbulent) air than if it where intruduced AXIALLY (w.r.t. the ladder).

I have already discarded, dumped, ditched a static arc, since it would require electrode cooling.

Quote:

"I AM going to "recycle" some of the NO2 by feedback. "
No, dont do this, it would be bad.
"Why?"

Air passing into the arc comes out with a concentration of nitrogen oxides that does not depend on the amount going in. Its wasted NO2. Aditionally people seem to get better results if the air going into the arc chamber is dry.

Fine. Won't do it then. No problem. Actually, one less problem.

Quote:

You might want to take heed from the death of a NST in jacobs ladder config particually.
"The company manufacturing this particular NST gave me their word that it would work in a jocob's ladder config."

Read the thread on roguesci. While it will certainly work, how long it will live is more the question. I came to the conclusion that the constant sparking might well be generating fast voltage spikes (eg from inductive kick) that degraded the insulation over time. Its also possible it simply overheated from the neer short current.

Time will tell.

Quote:

"I'm not intending to make explosives. I'm very afraid of explosives. I AM, however, very interested in rocket fuels."

There is not so much of a difference. What fuel/oxidiser are you planning to make with the nitric acid?

There is a very large difference. Rocket fuels deflagrate, explosives detonate. I was planning on trying out NC to start with.

Quote:

For the record, I do not have a 'problem' with your project. I hope it succeeds. You are quite entitled to tread your own path, make your own mistakes and we will learn from it either way. I will try to help, you can listen to my suggestions or not, if something is covered well elsewhere I do reserve the right to simply point you to it rather than type it all in myself. If you state as facts things I know to be wrong I do reserve the right to correct them and last but by no means least, if you tell people things are safe when they arnt, if you tell people something is doing less damage to them than they think - when you havnt read the information and very particually when it relates to NO2 - then I do reserve the right to call you a fucking idiot.

Everyone states as fact things that are wrong. It's the listeners responsibility to determine the truth of the statements. I could state that it's safe to jump out a window --- that does not make my fault if someone tries it.

And if you care to point out exactly where I've stated that NO2 is absolutely harmless, I'll accept the ad hominem title "fucking idiot". Mostly because sometimes I'm an idiot, everyone are, but also because I have a girlfriend, which means I'm occasionally fucking.

Does you hardware not support the concept of irony? And why are you so fond of the expression "fucking idiot"? Is there something Mr. Freud would find interesting here?

[Edited on 2004-2-24 by axehandle]

[Edited on 2004-2-24 by axehandle]

[Edited on 2004-2-24 by axehandle]

stop now, please

Polverone - 24-2-2004 at 09:25

I am sure Marvin could come back with another point-by-point discussion of your post, just like you did of his. I will ask him (or anyone else) to refrain though, unless it is to discuss technical points such as the efficiency of various arc configurations, or to clarify health aspects of the problem (without any further insults or wounded defensiveness from any party).

This discussion board covers many potentially dangerous topics. Nobody likes a dead or damaged experimentalist, least of all the experimentalist. You can learn from experience, but learning from experience alone carries too high a price.

I appreciate that you have a sense of humor, but please refrain from making jokes about hazardous activities outside of Whimsy. It is very difficult to discern tone from a text-only medium, and far more lurking "guests" than registered members visit this site. They can't ask for clarification. I would say that anyone who imitates what they read on a web discussion board shouldn't be surprised if things go badly. However, I would like this to be a web discussion board of high quality that doesn't injure the curiously-imitative.

axehandle - 24-2-2004 at 09:30

I'll gladly stop. Wasn't me who started it anyway.....

I'll just go away and sulk for a while now.

OSHA Gas Concentration Limits

hodges - 24-2-2004 at 17:53

I notice the following from MSDS:
NO2 5ppm
Cl2 1ppm
I2 0.1ppm

Why are the limits for chlorine and especially iodine so much lower than for nitrogen dioxide? Also, does anyone know whether limits in ppm (parts per million) are by volume? Or by weight? If by volume I can see why I2 would be so low given that it is a solid.

Most toxic gases have OSHA limits of 1ppm. If volume, this is 1ml/m^3. Now, I figure there is 75 m^3 in the room I do my experiments in. Thus I always try to keep any reaction small enough that a maximum of 75ml of gas would be produced in a "worst case" (i.e. it all goes into the room) scenario. Obviously this is not foolproof - the concentration may be higher nearby, or I may miscalculate - but at least my goal is to stay under 1ppm.

Theoretic - 25-2-2004 at 02:12

"There is a very large difference. Rocket fuels deflagrate, explosives detonate. I was planning on trying out NC to start with."
Ever heard of DDT (deflagration-to-detonation transition)?
Fully-nitrated nitrocellulose undergoes DDT under ANY confinement (even if ignited in an open jar).
Additives (such as AN, for example) change that.

Saerynide - 25-2-2004 at 02:45

Quote:

Originally posted by hodges
I notice the following from MSDS:
NO2 5ppm
Cl2 1ppm
I2 0.1ppm

Why are the limits for chlorine and especially iodine so much lower than for nitrogen dioxide? Also, does anyone know whether limits in ppm (parts per million) are by volume? Or by weight? If by volume I can see why I2 would be so low given that it is a solid.

Doesnt I2 sublime?

Im surprised that the limit for Cl2 is less than that of NO2. I thought NO2 was more harmful than Cl2....

axehandle - 25-2-2004 at 03:51

Quote:

"There is a very large difference. Rocket fuels deflagrate, explosives detonate. I was planning on trying out NC to start with."
Ever heard of DDT (deflagration-to-detonation transition)?
Fully-nitrated nitrocellulose undergoes DDT under ANY confinement (even if ignited in an open jar).
Additives (such as AN, for example) change that.

I know, but thanks for pointing it out. I was planning to construct an end-burner fuel grain consisting of nitrated sawdust or similar with some sort of binder+inhibitor; dextrine or something similar. I haven't given it much though really, it's far into the future.

axehandle - 25-2-2004 at 03:54

Quote:

Doesnt I2 sublime?

Im surprised that the limit for Cl2 is less than that of NO2. I thought NO2 was more harmful than Cl2....

The value for I2 is probably for very fine dust.

And the lower value for NO2 might be because (this is speculation) NO2 damage accumulates, whereas Cl2 damage does not? I know not.

It's quite interesting though. Pity I like animals too much to do some tests

Btw, I conduct my experiments in a room that's about 25 square meters with a roof height of approx. 2.8m. That gives 70 cubic meters. Now, if I only had a way to determine the production of NO2 in kg/s, I could do some serious calculations, but I'll have to estimate that by using the apparatus, recording the time, and titrating the product. Then I can (assuming 100% absorption) calculate the time to reach the safety limit in case of worst case scenario: Leak between reactor and buffer jar. Very interesting, this.

Whoha! Just found out a way to rig an alarm. The airflow should be constant throughout the system right? If it differs between the pump output and the hole-through-wall-outlet, then there's a leak! This should be possible to do in a not too complex way, perhaps using two units that average the pressure over discrete time periods, say 1 minute.... but now I'm ranting.

[Edited on 2004-2-25 by axehandle]

Saerynide - 25-2-2004 at 05:29

Quote:

Originally posted by axehandle

Quote:

Doesnt I2 sublime?

Im surprised that the limit for Cl2 is less than that of NO2. I thought NO2 was more harmful than Cl2....

The value for I2 is probably for very fine dust.

And the lower value for NO2 might be because (this is speculation) NO2 damage accumulates, whereas Cl2 damage does not? I know not.

They gave NO2 a higher limit than Cl2, which would be saying that more NO2 can be tolerated than Cl2... which I do not understand. Btw, I read somewhere that Cl2 poisoning is also cumulative

axehandle - 25-2-2004 at 05:36

Quote:

They gave NO2 a higher limit than Cl2, which would be saying that more NO2 can be tolerated than Cl2... which I do not understand. Btw, I read somewhere that Cl2 poisoning is also cumulative

Ah, I typed "lower" when I should have typed "higher". I must have been thinking of the human body's tolerance. Cl2 also cumulative? Hmm, I don't know. This needs further research. I'm not a physician, nor an expertise in poisons....

FWIW, before I fully understood the peril of NO2 sniffing, I probably got a lungful over time, so to speak. Haven't dropped dead yet though, but I'll make damned sure I'm not exposed again....

[Edited on 2004-2-25 by axehandle]

Magpie - 25-2-2004 at 21:25

Iodine does sublime fairly readily so perhaps those levels are for the gaeous state.

At one time I worked in a paper pulp mill that used CaSO3 to digest wood. They made this on-site by burning sulfur to SO2. I used to have to occaisionally calibrate the operators' Orsat analysis equipment. They used this to measure the strength of their SO2 gas stream. It would almost gag me just being in the room where the operators worked 8 hr/day for decades. They claimed that they were quite healthy.

Elemental chlorine was also used there as a pulp bleach. Occaisionally there would be a gas leak. When I got a whiff of this I always turned right around and left the area. It amazes me that there were no alarms or warnings by management. It would probably be different today.

Interesting setback / development

axehandle - 27-2-2004 at 04:57

Seems that dehydrated gypsum is hygroscopic. No arc. I measured the resistance between the electrode connections. It was 2.62 kOhm.

So I said to myself: If I feed a high voltage high current through this overnight the water should evaporate.

Said and done. Connected to the 220V AC mains overnight. The resistance is now up to 3.06kOhm.

Now I'm running the reactor using the NST. The internal temperature is up to 49C so far, which could indicate either water evaporation or an arc. I won't test-sniff it this time though. I'm just going to let it run until all those pesky water molecules have been obliterated.

The NST is getting very hot. I don't know if that's normal. It's supposed to be short circuit protected. I'm going with the assumption that it's normal. Probably should fetch the fan just in case....

I can't find my book of constants, so now I'm going to google for the conductivity of air.

If all else fails, I'm not out of luck. There are two bolts protruding from the reactor, both immersed in the gypsum very close to the electrodes. If I heat those using a hot-plate or a propane burner, they should heat up the gypsum inside the vessel.....

Saerynide - 27-2-2004 at 05:09

I suppose you can always go back to the old one.

axehandle - 27-2-2004 at 05:24

No way, no way. The new reactor has tormented me for two-three weeks now, and I'll never give up until it works.

Saerynide - 27-2-2004 at 06:23

Hehehehe.. Stubborness is the way to success. I never give up on good ideas

axehandle - 27-2-2004 at 06:24

Come to think of it, I don't give up on bad ideas either....

Marvin - 27-2-2004 at 10:57

I would be bothered the plaster of paris would dehydrate during the arcing. Have you thought about using sparkplug feeds to the arc chamber?

Insulation (mainly the air gaps might not strictly handle the voltage but if you use 2 it might provide enough if the arc gap start is close enough together.

Tacho - 27-2-2004 at 11:43

I hope you mean Mohms, because if your insulation is down to 3 kohms, you sure have a problem.

Instead of plaster of paris think of
Dental casting investment. This is what dentists and artists use to make molds for casted metals.

Is one of my favorite materials, you mix with water like plaster of paris (sometimes with microsilica emultion), but when it hardens, it resist VERY high temperatures. It does not contract or expand much. I use it to make refractary pieces. Take a look at the heating unit in my "versatile glassware" thread, it´s made of it.

Anyway, once it is refractary, I suppose the heating will drive away all the water, leaving a dehydratated cement with high eletrical resistance.

I used to know the chemistry of its hardening. The word "phosphate" comes to my mind.

You can find it at any destist supply shop.

I sugest you do a little search on this material, since you may find many uses for it.

axehandle - 27-2-2004 at 17:46

We shall see. I think I have driven out almost all of the water now. Otherwise, I'll find an alternative "place-holder".

GAK

axehandle - 1-3-2004 at 03:53

:mad:

The gypsum method didn't work... the dehydrated gypsum is hygroscopic... so I tried clay (which cracked) (and has considerable shrinkage). For the moment, I'm a bit out of ideas. The dental filling thing seems promising, but I doubt I could get hold of any.

I think I'm going to make an experiment using bentonite mixed with distilled water. That little bugger shouldn't conduct much. But it's still clay, and hence a pain to work with.

This is SO frustrating. I know the design works, and then I have problems for a month keeping the electrodes in place. Time which could be used making nitric is wasted on waiting for clay to dry out etc....

Saerynide - 1-3-2004 at 07:34

I get what you mean. Im still trying to find a freaking flower pot for electrolytic H2SO4 production :mad:

It pisses me off cause everytime I try it, SOMETHING has to go wrong, but everything else goes right!!! If only you could combine all the rights and toss out the wrongs :mad:

Keep up the optimistic attitude

axehandle - 1-3-2004 at 08:36

Well, this is the first time someone has called me an optimist, but there might be some merit to the designation....

I have a new idea about the clay. As I see it, the main problem is that is shrinks as it dries.

So --- maybe, just maybe, if one where to replace the water with a solvent that evaporates very quickly (like e.g. acetone), the clay wouldn't shrink but be full of small air voids instead.

It's worth a shot.

Btw, what kind of flower pot are you looking for?

Saerynide - 2-3-2004 at 01:59

A flower pot that is unglazed and thin enough to use for a salt bridge.

axehandle - 3-3-2004 at 05:46

Quote:

A flower pot that is unglazed and thin enough to use for a salt bridge.

That's going to be hard to find

.

If you don't mind the labor, you could buy one that is too thick and sand it down to an appropriate thickness. The process will consume sandpaper at an alarming rate though......

Saerynide - 3-3-2004 at 07:51

My god! Thats just crazy

Guess I'll never get my salt bridge

Edit: Btw, what would be the max thickness where it could still work?

[Edited on 3-3-2004 by Saerynide]

axehandle - 3-3-2004 at 10:56

I'm sorry, I have absolutely no idea how thin it has to be. I guess it depends on what type of clay was used, and which temperature was used when firing it.

But you shouldn't have to sand down the entire pot. A 10x10cm area would suffice, no?

And you could use one of those machines with sandpaper on that vibrates. That would save you the excercise of doing it by hand.

Tacho - 13-3-2004 at 11:34

Axehandle,
I know you are working in sulfuric acid production, but how is BE reactor. This is a good project and there are no news in you site.

axehandle - 13-3-2004 at 13:04

Well, not being a female, I have no simultaneous capacity and the SO3 reactor takes up all the time I've got. The burner is almost done, and then there's basically only the heater left.

I intend to continue the B-E reactor after the sulfuric plant is done. I have some improvements in mind, namely a static arc drawn out in an oval shape by magnets (if I can find full-wave rectifiers rated for 10kV, 60mA...). I'll cast the outer lightning ring in brass. It will be water-cooled. The inner electrode (a rod) will be consumed over time and must be constructed so it can be fed down. Did that make any sense?

I'm still evaluating materials. Gee, I didn't know material science was this exciting. Heat capacity, ease of work, conductivity... etc.

I'm actually feeling a bit stressed out at the moment.

Testing a concept --- here we go

axehandle - 20-8-2004 at 18:37

OK. Since I could never find a good way to mount electrodes in my old reactor contraption, I kind of gave up. Until now, that is. Sometimes ideas come to me in my sleep, and that was happened today.

The new electrode idea is very simple, much simpler than the old one -- and as many would probably agree; simple ideas are the hardest to come up with but tend to work best.

It struck me: Why not use simple disposable electrodes that can be replaced as they are burnt up? Made of simple, always available 2mm steel wire that is easily bent into shape? Why not? Why not take that one step further, shall we:

Two simple bolts, interdistance around 20mm, protrude from the bottom into the reactor chamber. The bolts both have 2mm holes drilled lengthwise halfway through them. The disposable electrodes are simply stuck down into the holes and bent to shape. The very small intersection area of the wire will also insulate the electrode holders (the bolts), and thus the reactor bottom, from the immense heat building up in the electrode wire, or so I hope. If not, using very much larger bolts should help. I'm attaching a very simple drawing.

Proof of concept using 2mm mild steel wire as discharge electrodes:

The test mount (I have 1.5mm, 3mm, 4mm, upto 17mm drill bits but couldn't find any 2mm ones so I had to tie the electrodes in place using 0.5mm steel wire...):

I ran this contraption for a 2..3 minute run after having wetted the inside of the glass jar with water to become nitric acid. Lacking (unable to find more like it) blue litmus paper I sacrified my tongue in the interest of science. I think I nitrated it -- it was the most foul, sour, evil stuff I've ever tasted and it still hurts. I was still pleased though... The steel wire showed no sign of turning red hot, although it got very hot as my hand found out touching it by mistake...

Tomorrow I'm getting some 2mm drill bits and a threaded rod (will be easier to drill in than nuts). I'm back in business!!!!!!!!!

Magpie - 20-8-2004 at 18:55

Very nice work. I continue to enjoy your work and pictures. Would you consider selling tickets for a tour of your lab?

Saerynide - 20-8-2004 at 19:45

Nice! Good to see you're gonna finish it

darkflame89 - 21-8-2004 at 01:03

I am waiting most eagerly to see your work finished.

remember to update your site with your new "findings".

axehandle - 21-8-2004 at 05:21

Aaargghh! No pressure, no pressure...

Edit1: Holes drilled. I actually came up with an improvement: The holes will be slightly (1mm more) larger than the electrodes, and tha latter will be kept in place by set screws going into the bolts perpendically. That it if I can find an M3 threading bit... I know I have one around here somewhere... might have to use a thicker threaded rod as well. Ah, it's all coming back to me.

BTW, what are those threading things for making threaded holes ("gängtappar" for any Swedes here) called in English? I know their opposite sex is called "dies", at least I think so.

Edit2: Thinking that it would be much easier to work with aluminium threaded rod (or copper, or brass -- still, Al should be the most resistant to NO2 + gaseous HNO3). I'll have to thread a round bar myself ofcourse. Hmm, can't get any until Monday, but I can use my freshly drilled steel nuts to experiment with until then. Have to see what temperature the bolts and the vessel get to, if it's too high I'll have to employ two identical reactors in series so they only get ~1/2 as hot (simple enough using 5 litre jam jars as I am). It's certainly not borosilicate glass, heh...

[Edited on 2004-8-21 by axehandle]

S.C. Wack - 21-8-2004 at 08:33

One makes threaded holes with a tap. Taper, plug, and bottoming taps. Nice madproject.

axehandle - 21-8-2004 at 10:06

Taps it is, then.

Just did a 10 minute test run, taking pictures of the air inside the reactor getting browner and browner with NO2:
http://species8472.dyndns.org/no2/testing.html

Note that the vessel is hemetically sealed: Wouldn't want all that nasty NO2 out in my living room...

[Edited on 2004-8-21 by axehandle]

froot - 21-8-2004 at 11:57

Very nice axe. Just a thought:
What if one did this experiment under a predetermined pressure in a pressurised vessel. Wouldn't the pressure decrease as NO2 was formed?
If so, the pressure could be maintained by a feed from an air compressor. If all goes according to my 'theory' the NO2 would form HNO3 with any water present in the vessel and condense due to the pressure. This could then be collected at an outlet valve at the bottom of the vessel.
I suppose there could be an explosion risk involved.

axehandle - 21-8-2004 at 12:05

Why keep the vessel pressurized? It won't save time, the air throughput will be the same, right, although replenished more infrequently? Although I can imagine that the reaction would be more efficient with rising pressure, I don't know -- perhaps someone does?

Still, I'd guess the absorption of the NO2 would be more efficient at higher pressurizes, but this is a guess also.

My plan for absorption is bubbling the output air + NO2 mix through water --- keeping water inside the reactor would require cooling of the same; it gets as hot as a lightbulb, not surprising when using a 540W arc inside a glass jar

.

Edit1: Another note -- mounting plasma discharge electrodes inside a glass jar is very non-trivial. I gave up on the problem and it took me half a year to solve the problem (could be me being stupic rather than the problem being hard though), and that's without allowing water condensing in the reactor bottom. Even supposedly de-ionized water gets somewhat conductive when used with voltages in the 10kV range, stopping the formation of any arc. I had many woes with different sulutions.

[Edited on 2004-8-21 by axehandle]

BromicAcid - 21-8-2004 at 15:28

What is the exact mechanism for NOx formation?

Is it formation of nascent oxygen followed by attack on molecular dioxygen to form ozone and its subsequent action on nitrogen, or is it the action of the nascent oxygen on the dinitrogen, or is it the action of electrical discharge on dinitrogen to form nascent nitrogen and its action on dioxygen, or some combination thereof?

I'm asking this because weather you should run this under pressure or not is the same kind of equilibrium shift that is involved in any reaction.

If the reaction produces more mols of gas then the initial products it would be good to run it under reduced pressure, if it produces less mols then it would be good to run under pressure.

Personally I like the idea of a constant stream of atmosphere being lead into the reactor and an exit tube running though a bubbler into water and that exit tube running doing other things but finally ending in a vacuum pump to keep things flowing in the direction necessary to keep dissolution of the products.

axehandle - 21-8-2004 at 15:48

From the little information I've found regarding the physics of this reaction, it's hard to deduce exactly what is happening. All sources cite the formation of nitrogen monoxide NO, which at room temp quite immediately graps another oxygen like
2NO + O2 <--> 2NO2

The few (very few, like 2) sources regarding this reaction I've seen claim that N2 and O2 are both split into free atoms 2N + 2O at plasma temperatures, but whether its really true or if it's only one of {N2, O2} being split, and in that case which one, I don't know.

It seems to work anyhow, but I'd very much want to know exactly what's going on.

darkflame89 - 22-8-2004 at 01:17

Ho-ho, those pictures were certainly very good. Very nice to see the brown gas form. You just need to add some sort of a valve to it to let the nitrogen dioxide out, cool it to form the dimer(easier to handle that way), and at the same time give the reactor fresh air to react with.

By the way, the formation of NOx gases is truly puzzling. For example, the catalytic oxidation of ammonia using chromium (III) oxide is a bit odd. Refer to http://www.chem.leeds.ac.uk/delights/texts/expt_14.html

When the reaction is carried out in a open vessel, mostly nitrogen gas is formed. but if the reaction is carried out in an enclosed jar, nitrogen dioxide is formed.

maxke - 22-8-2004 at 02:26

I think a setup with a compressor will still benefit a setup like the one shown on your site axehandle.

compressor <-> pressure barrel (3bar controlled) <-> valve 1 <-> arc chamber <-> valve 2 <-> water absorption 1 <-> water absorption 2

My reasoning : if you want to keep no2 from releasing into your room you need to push it away somehow , to the absorption vessel.

So if after 10 minutes a batch of NO2 is ready , valve 1 and valve 2 are opened so to push the NO2 into the absortion and to purge all or almost all NO2 in the arc chamber with somewhat pressurized air.

I would setup the compressor so that it turns on when the pressure drops under 2.5 bar and turns off when the pressure is greater than 3 bar. (this requires a pressure sensor and shmitt trigger setup/ or any other setup that does the same)

So if you'd like to fully automate the process , you could also set the valves to open / close at set intervals , and also you could modify your absorption vessels to purge fully absorbed NO2 / HNO3 after 60 minutes ... all this for the sake of amateur rocket science right ??

What do you think ?

axehandle - 22-8-2004 at 08:28

I don't know. A couple of places I've read that formation of NO2 gets faster as the concentration of same goes up, up to a point ofcourse.

I suspect the only way to find out whether "batch" air replacement of "continous" air replacement is optimal is to try them both, which is simple enough using a timer and an air pump.

I like the high pressure idea, but I'm trying to keep the design as simple as possible -- which would somewhat be thwarted by having to design a vessel that can stand positive inside pressures in the 2..3 bar range. Worth lots of thinking though...

I've added a couple of pictures of what the electrodes looked like after having been left in NO2 overnight at the bottom of this log:
http://species8472.dyndns.org/no2/testing.html

[Edited on 2004-8-22 by axehandle]

froot - 22-8-2004 at 11:45

Another problematic factor you mentioned axe is temperature control. The vessel would then have to be placed in a water jacket to keep it cool which will only add to the complication.
I suppose the best is to try it which I'm keen to do once I've acquired a HV source.

I was also wondering if it is possible to mix the NO2 with water vapour hoping the NO2 would be absorbed by the water in vapour phase, being aided by the pressure. This would mean that the overall volume of gasses would decrease hence lowering the pressure and as mentioned above a feedback triggers the compressor to reinstate a pressurised environment.
The water vapour could be ensured by some kind of variable humidifying setup between the compressor and the pressure vessel. It may be true that the concentration of HNO3 collected can be controlled by adjusting the humidifier.
The pressure vessel would probably need to consist of 2 parts, the reactor itself where temperatures are relatively higher, and a condensor, where temperatures are forced to cool. This is where, if my theory 'holds water', the HNO3 is collected using a timed solenoid or a simple ball valve. The design of the vessel would have to be such that these conditions are optimised. One would have to design the outlet in order to prevent the the acid from spraying everywhere as a result of the pressure.

darkflame89 - 24-8-2004 at 02:07

Is it possible to use a induction coil instead of NST transformer? As i have no access to such transformers, is it alright if i used other sources of plasma discharge?

Cyrus - 24-8-2004 at 17:35

Saerynide, why not make your own unglazed clay pot? Raku clay is very porous to begin with, and if you add grog (bits of prefired and ground up clay) the clay will get even more porous.

Raku clay is cheap. 10 dollars for 25 pounds.

It has high thermal shock resistance and can be fired quickly at low temperatures- think bonfire.

With this method you could form nearly any kind or shape of reaction vessel you wanted.

It could say "made by Saerynide industries." on the bottom. A definite bonus. When people ask where you got it, just point to the label.

Then again, it is just another thing that can go wrong.

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