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Author: Subject: Birkeland-Eyde reactor for making nitric acid.
Marvin
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[*] posted on 5-4-2005 at 03:55


IrC,

"Marvin the only thing you are proving here is that you are arrogant and full of yourself. "

I think after 2 and a half years on this forum thats gone one way or another already.

"To state someone is wrong without stating where and why is as useless as your ego, not to mention the fact that if you carefully read all 5 pages of this thread it is clear you contradict youself more than once."

If someone states that nuclear power plants are elephants on treadmills is it really worth explaining the whole concept of nuclear power from scratch, and then using average dietary requirements to fix an upper limit for the work a single elephant can do, or is it more time effective and just as useful to just point out someone doesnt know what they are talking about?

When I contradict myself, feel free to point it out. Genuine changes I like to call 'learning'.

"If long thin very high voltage arcs from toy transformers worked then everyone would be making acid instead of ending up in failure."

Do you blame the pen for a bad test score? High voltage, low current can do very well for a given power.

"The 2 million volts out of my Tesla coil produces lots of ozone and little NOx. But in the rotary gap with closely spaced electrodes, much lower voltages, and very high currents, the smell of NOx is overwhelming"

The output of the tesla coil is high frequency large volume. A lot of ions, little heated air. As I said, its a thermal process. The spark gap is a very dense discharge and thus the primary producer of nitrogen oxides, its far from ideal for a number of reasons. Its too hot for a start and this is wasted energy. Mainly, if it used most of the power in the primary tank circuit it wouldnt be a very good tesla coil, its a switch, its not a load.

"why don't you actually do something useful and tell how us all with carefully detailed plans how it should be built. "

Detailed plans are pointless, everyone has different requirements and equipment. Knowing how something works is more important than any single example.

"Better yet, build a working one yourself rather than verbally abuse others who do while you merely talk about it."

Thats a great idea. I should go away and build another one, furthur to my work slightly over a decade ago and which matched the trends in the theory while you continue making overly defended wild guesses in a subject you know nothing about based on an unrelated area of electronics. But wait! Heres an even better idea. How about I stick around and try to do my part toward a better S/N ratio.

"The very purpose of a forum like this should be for others to give their ideas and best advise"

I'm sure it would all be very friendly if all points of view were valid, but then it wouldnt really be a science would it? In chemistry there are good methods, safe methods, right answers and dire consequences. For me a chemistry forum should be as accurate and safe as possible.

"without worrying about whether or not someone like you is going to tear into them"

If something is outright wrong, it needs correcting. If its defended forcefully it needs tearing apart forcefully.

"rather than verbally abuse others"
"useless as your ego...personality of a rope...childish pissing contest antics of a reject from junior high school..."

The only person currently throwing insults is you.

fizzy,

There is a zero missing, its 5000V.


SC Wack has scanned one of the better books covering this subject, its Mellor Volume 8, his link is in the books thread. The arc fixation of air section is essential reading.
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SAM4CH
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[*] posted on 24-4-2005 at 15:25
Great Transformer!?


I got a great high voltage transformer its output = 17KV,1A, it is italian trans., but its output is DC not AC I want to run it to produce HNO3 by (ARC furnace) but I need advice before running it like safty, design of reactor, arc .. etc.
Note: I am sure about it and its price is 6000$
Thanks
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Marvin
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[*] posted on 25-4-2005 at 13:15


You need more than just advice, you need a miricle.

It sounds like a bad power source. Transformers by themself cannot be DC, so you have additional electronics somewhere which will almost certainly hate what you have planned. Find out more about the device if you've allready got one, you will need to tap the AC output of the transformer stage directly, and disconnect the rest.

For the high current of 1 amp the voltage maybe a little high. I would expect to be able to climb into the arc chamber and you'll still have problems raising the impedence. I would also suggest spending an additional kilowatt or so running an electromagnet from mains in order to move to a magnetic field design. This will need water cooling even if nothing else does.

Read the sections on this process in Mellor 8. Right now Mellor is the best friend you have.

Above all I suggest going back to the low power transformer and chamber and not moving on until it works properly. If you cant make a decent design at a few hundred watts I think you'll crash and burn at 17KW. Even simple things become complicated, electrodes will probably need liquid cooling (spot any potential problems with water cooling both electrodes?) and you'll need to do a lot better than just bubbling the output gas through water, you'll need seperate stages for cooling and extraction.
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SAM4CH
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[*] posted on 8-5-2005 at 04:25


Marvin, how can I find Mellor8, I tried with rapidshare but no way.
"A Comprehensive Treatise on Inorganic and Theoretical Chemistry" its price is 240*2$!!
Can you help me in this please?!
I need only the section which talk about nitric acid and birkeland eyde process.

[Edited on 8-5-2005 by SAM4CH]

[Edited on 8-5-2005 by SAM4CH]
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Duster
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[*] posted on 16-5-2005 at 08:51


Sorry to jump in like this but I would like to share what I plan to make here shortly... Hopefully within the next couple of weeks (soon as I get home).

Just the other day I bought a 15kv NST from ebay No guarentee but for the price, as long as it works to prove itself thats fine with me. I can always buy another, better one...

For the reaction chamber itself, this is where I think I get a bit... Abitious...

I remember back home there was a rather large (we're talking 36" high, and at least a 20" diameter) crock pot or something. No holes in it, and at least an inch thick of clay.. I belive the outside was glazed but not the inside. In any case, I had an idea (of course). I could probably find a couple of these around where I live (I already called my brother and recruited him to find some), and I figure a nice big reaction vessel that like wouldnt have to worry about cooling as much as a smaller one. Also, the jacobs ladder could be about 48" tall (slightly protruding from the top of the bottom pot).

I have a couple fans at home... One of which is damn near a mega blower, but I also have a couple of smaller ones laying around. Im wondering how much airflow would be needed. I figure trial and error will decide...

Im also seeing at least 3 absorber tanks (aka glass jars).

Dont get me wrong, this could be FAR from ideal, but going by what I have seen in this thread (heat being an issue, absorbing being an issue, air pressure, etc etc) I would be led to belive that a large reaction chamber with multiple absorber tanks would be an ideal setup coupled with at least a moderate (but not violent) air inlet...

As for wanting to do this... Well for one its cheap (the NST cost me <$50), its simple, I just bought a glass distilling setup specfically for nitric acid, and if I could make large enough amounts of HNO3, I could produce H2SO4 (I think).

Well, thats it for my post... For now... If this thread isnt completly dead when I actually put all this together, I'll post a few pics... Im working on my own website (its comming along nicely so far) so I will probably have the pictures hosted there.

Lastly, if this setup does work, at least somewhat well... I figure I could buy a second NST and have them alternating 10 on 10 off (minutes that is) so they dont burn out... If I cant safely have them do this on the same jacobs ladder, I could also have a second reactor vessel but have it pump its output into the same absorber jars.

Hope 8 days doesnt count as bringing up a dead topic...




Duster
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jpsmith123
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[*] posted on 29-6-2005 at 18:17


Although I'm not planning on trying to make any HNO3 in the near future, it is something I looked into once.

I found a few patents on the subject, most of which involved portable NO generation for medical use, and a few involved local fertilizer production for farms.

Most of the patents made use of an electric arc to produce the NO, but patent #5,692,495 was interesting because it employed a noble metal catalyst (e.g., platinum) at a temperature between 300 and 1200 degrees C, and "preferably" between 500 and 1200 degrees C.

Another method that might work and might be less troublesome than an electric arc is a dielectric barrier discharge.
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[*] posted on 29-6-2005 at 18:44


Quote:
Originally posted by jpsmith123
Another method that might work and might be less troublesome than an electric arc is a dielectric barrier discharge.


Is that like pointing a Tesla coil at a piece of plate glass and drawing arcs off the opposite side? That just makes O3, IIRC.

Tim




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jpsmith123
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[*] posted on 29-6-2005 at 20:31


It's similar in the sense that you've got a high AC voltage and an insulator...I guess that would be an example of a DBD, albeit not a technologically useful one.

Here's a paper that describes it:

http://sunsite.wits.ac.za/iupac/publications/pac/1999/71_10_...

I would guess that the major design issue to produce NO is to make sure that the average electron energy in the discharge is around 10 ev, i.e., enough to break the N2 molecule apart.


Quote:
Originally posted by 12AX7
Quote:
Originally posted by jpsmith123
Another method that might work and might be less troublesome than an electric arc is a dielectric barrier discharge.


Is that like pointing a Tesla coil at a piece of plate glass and drawing arcs off the opposite side? That just makes O3, IIRC.

Tim
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Marvin
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[*] posted on 29-6-2005 at 20:49


I hate to sound like a broken record but this idea comes up regulally and the answer is the same. NO is produced thermally. Silient electric discharges are useful becuase they produced broken molecules without the high temperatures that normally decomposes down to the most stable products. By the same point, any lower temperature process involving air cannot possible produce a higher concentration of NOx gasses than an arc furnace no matter what the catalyst. Even at 1200C the concenctration of NO will be small, getting strong nitric acid from the few percent of a 3000C arc is hard enough.
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jpsmith123
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[*] posted on 29-6-2005 at 23:21


Hello Marvin,

I'm not sure I understand exactly what you're saying. Are you saying that it's impossible to produce any NO in a dielectric barrier discharge, or are you saying that it is possible to do so, but only at reduced efficiency, compared to an arc discharge (i.e., lower NO output per unit of input energy)?

I also cited a patent involving a method to produce NO using a catalyst at a temperature between 500 and 1200 degrees C. With regard to this, are you saying the catalyst won't help at all or that it will not be as energy efficient as an electric arc? Please elaborate.


Quote:
Originally posted by Marvin
I hate to sound like a broken record but this idea comes up regulally and the answer is the same. NO is produced thermally. Silient electric discharges are useful becuase they produced broken molecules without the high temperatures that normally decomposes down to the most stable products. By the same point, any lower temperature process involving air cannot possible produce a higher concentration of NOx gasses than an arc furnace no matter what the catalyst. Even at 1200C the concenctration of NO will be small, getting strong nitric acid from the few percent of a 3000C arc is hard enough.
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[*] posted on 3-7-2005 at 11:10


I just throw in the garbage a 10KV external transformer for neon signs thinking... there is no way I can find a way to use it at home... well, now I read this threat.

BTW guys... in this forum we have a chance to get insights from people with degrees and decades on the fields. Try to get criticism in a positive way instead of being defensive.
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[*] posted on 14-8-2005 at 12:33
Commercial Plasma Cutting Torch As Birkeland-Eide Reactor?


I wonder if a plasma cutting torch (like the following one for sale on ebay) would produce lots of nitric oxide, and if not, why?

http://cgi.ebay.com/PLASMA-CUTTER-Cutting-torch-220v-Air-hoo...
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[*] posted on 28-8-2005 at 06:49


the plasma cutter would be a far push.
In order for the device to work... you need to have an anode and cathode. (complete the path to the ground)

So you would place it near some conductive surface, initiate the plasma... and... ohhh the conductive surface is gone, spattered into millions of tiny particles. If you dry arc, you pit down your electrode really really fast and those are about $15/ a pop.

No, a commerical plasma cutter would not be of any use for making nitric acid. unless... maybe you did some modifications and used compressed N2 and O2 already mixed correctly.

You could just as well, spend a lot less to build something that uses compressed gasses fed through an arc.
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[*] posted on 28-8-2005 at 07:49


Hello Uber luminal,

I realize that a plasma torch may not be a cheap way to go, but I don't see why it wouldn't work. The advantage would be high power, and almost ready to go out of the box; i.e., power supply, igniter, one electrode and gas input channel already set up.

If, in the ebay description, the "cutting gas" was air (the Birkeland-Eyde process uses air, no?), and the anode material and geometry were suitably chosen (say, a piece of graphite tubing), why wouldn't it be expected to make nitric oxide?

Regards,
Joe
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[*] posted on 28-8-2005 at 15:03


I would say it would be because a plasma cutter... Well... Does just that, cut. I do belive his point is that any electrodes wouldnt last long enough to be of any value. I have no doubt it would work, but only to an extent. And only for a brief period.

I would see an ARC welder to be a better choice, just convert it so it runs on DC...

But even then, a NST seems just fine...




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[*] posted on 28-8-2005 at 17:56


AC/DC doesn't matter. You just have to get to a high enough temperature.
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[*] posted on 28-8-2005 at 18:43


Ah true, got me there. I was thinking of something else...



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[*] posted on 29-8-2005 at 10:54


with a plasma cutter, you need 3 things.

heres the thing with the plasma cutter...

You need about 90 psi at 5+ CFM. Constantly while in operation, plus the post flow cooling operation. So, you do some math, and figure out that you will need a pretty big tank, with a pretty big compressor to run for a period of time.

a typical plasma cutter needs a 30 or 40 gallon compressed air tank with a 6 CFM @ 90 psi compressor. This runs about $500-600. and takes up a large amount of space.

IF you go with the cylinders route, I have eaten a full tank of 255 Ft^3 N2 gas in about an hours worth of work. that was however at 70 psi, so you could go as low as say.. 55 psi. so Just calculate again, but either way, the tank wont last very long.

The biggest problem... Your powersupply and electrodes, which are made from copper cooled by compressed air. (duh). However you power supply is prone to overheating. a lot. You would need to buy a large power supply with a high duty cycle.(even for the lowest possible setting).

One of the plasma cutters I have, (Powermax 1000, costs about $2000 USD), could run, on the lowest settings, for about 4 min, constantly. Thats a long time. After 4 min, the controller unit says... no, thats enough, and stops the current to let everything cool down.

another plasma cutter I have, (no name, cheap POS, about $500) has a really crappy duty cylce even at the lowest settings. very annoying, while cutting 1/16 steel, it decides about 1 min is enough and stops to cool.

like I said, $500 spent on a cheap TIG welder, and build a compression chamber would be money better spent (plus you could use the TIG welder, to build the thing :)

AGAIN, you would need to create a small plasma cloud onto a conductive surface, which would go away, leaving your cloud elongated, and the machine would either stop the current, OR you would pit the crap out of the electrode inside the torch. Dryarc is not good for your torch. Those little electrodes are annoyingly expensive.
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biggrin.gif posted on 27-10-2006 at 01:46


Oh MARVIN are you playing with us ?:(
please tell us how to make it (easy),
you know, we are amateurs
Thanks MARVIN :D
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[*] posted on 25-10-2007 at 22:13


so has anyone made any progress? sorry for disturbing the dead (thread)
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497
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[*] posted on 25-10-2007 at 22:53


i had the idea (probably not new) of using a stationary arc and passing a stream of air through it at a relatively hight speed, ie. from a large hypodermic needle pointed at the arc. i realize the problem is the electrodes. i have access to TIG welding electrodes of all kinds (thoriated tungsten etc.) i was wondering if anyone has tried this or knows how well they hold up in air for extended period of time? i also have access to a TIG welder that may be able to be used as a power supply. being in Alaska the shipping cost for nitric is insane (even more so than everything else)... not to mention the initial price and all the government lists you get on. i suppose just being a member of this forum gets you on most of them anyway... :P

[Edited on 25-10-2007 by 497]
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[*] posted on 26-10-2007 at 20:12


Hmm, if this works out I might have to try it as well. I had planned to use the Ostwald process once I run out of nitrate salts, but this could be a lot easier although less efficient. Maybe a watercooled glass chimney and an arc from my pole transformer. Plus it would give me an excuse to have a large multi-kW jacobs ladder running continously in my shop that is actually doing something. If they make a medication to treat polyprojectitus, I need it.:P



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[*] posted on 26-10-2007 at 23:51


well i did some testing with tungsten electrodes without shield gas. not pretty. they got crapped up (oxide i assume) in a few seconds to the point that the arc died. but not really a good test because its very low voltage high amp (~20) but soon i'll try it again with a furnace transformer. while i'm at it i think i'll try graphite rods out of D cells. i suspect these may be the best option. the contamination with carbon might be an issue though. i love the general idea of producing nitric from air though, best method ive seen yet, even with the low efficiency.
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[*] posted on 27-10-2007 at 00:46


I would have thought that the benefit of moving the arc along the electrode was that any given patch has a low duty-cycle and does not get ungodly hot and start to melt/evaporate...
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[*] posted on 28-10-2007 at 18:00


that was my logic too. but apparently its not a problem for an oil furnace transformer. apparently its not powerful enough to damage the electrodes even though the arc is stationary, ~1 mm steel welding rod had no visible damage after many minutes of running. a little less powerful than i had hoped (draws ~50 watts.) it makes an arc maybe 2 cm at most. i did make a jacobs ladder and after seeing how fast the arc travels (completes a full cycle quite a few times per second) i wonder whether it might be better because it seems like it might allow the air to cool faster and retain more NO2. with a stationary arc it takes about 8 minutes to fill a liter glass with red NO2 (running it longer doesn't help). i then set the NO2 filed jar upside down in a container with 50 ml or water in the bottom. the color in the gas is gone by 5 minutes. so i did that 5 times and got enough acid to make the pH read 2. then i distilled it down to about 1 ml of fairly concentrated acid. it got hot and fizzed quite alot when dropped on baking soda. so it works! now i just have to get it to work without constantly babysitting it. the transformer seems to fair pretty well, getting only a little warm after running for and hour. any ideas on a good way to diffuse the NO2 into water? i'm not confident that simply bubbling it would work very well.

[Edited on 28-10-2007 by 497]
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