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Need advice on efficent Ozone generator for, N2O5 production ~ 80% HNO3

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LAN_403

Ocean Waves

Thu Nov 03 2011, 03:58PM

Registered Member #4181 Joined: Thu Nov 03 2011, 02:39PM
Location:
Posts: 42

Hello,
This is my first thread back from several years inactivity. I have to say its nice to be able to work on projects which involve using my brain again, working for a living can be such a drag sometimes.............

anyway I have managed to construct a arc reactor for making nitric acid using Pauling's arc furnace design, the old rabbit ears Jacobs ladder. however I was having problems with absorption and upon many hours of reading texts from Google books I found a quote from Helbig that the use of a "silent arc" discharge to produce Ozone says and i quote "it is easy to get HNO3 of more than 80 per cent strength"

See "The fixation of atmospheric nitrogen, Joseph Knox" last paragraph of page 43

this happens because O3 very rapidly oxidizes NO and NO2 into N2O5, which in turn reacts with water to form HNO3 and NO, thus keeping the NO paired With O3 will push the absorption to very high efficiency in a short time.

I have a current working model, that produces some ozone but is not keeping up with formation of NO2, I have posted a youtube video here:

The generator is a olive jar, with grounded rolls of Al foil cut from beer cans on the inside, and expanded metal mesh on the outside stretched tight around the jar approx dimensions are 2.75" dia by 5.5" tall sealed inside of a ported 1 gallon Valasic pickle jar, of which a have many in my lab, lol gotta love pickles........

I get a good distribution of corona, but its very weak, I was unable to film the corona at all. I have tried a 12 kv 30ma neon and it does not preform better than the 8,000 volt 15 va static neutralizing xformer. I'm thinking the amount of corona power is fixed by the thickness of the dialectic.

BTW the 15va xformer is half the size of the neon but labeled 15 va???? Mistake??

What this comes down to is the need of a 5% Ozone stream at about .5 LPM, beyond that im stumped as there is not a lot of material out there on ozone that I could find, that was useful.........after days of searching and reading i ve come up with little to nothing........

Ocean

Forty

Thu Nov 03 2011, 04:31PM

Registered Member #3888 Joined: Sun May 15 2011, 09:50PM
Location: Erie, PA
Posts: 649

I believe you can increase the corona produced by altering the shape of your electrodes. lots of points tends to help as that's were the electric field gets concentrated. An air ionizer transformer that i have used four needles at its electrode.
I have imagined a corona generator in the form of a bed of sewing pins arranged in a grid and connected electrically by a layer of solder.
As i understand it, the corona will turn some of the atmospheric oxygen into ozone. so more corona will mean more ozone gas provided that there is excess oxygen. pumping in (or generating) oxygen near the corona generator will probably up your ozone production. you could even have one half of an electrolysis cell going underneath the generator, and the other half (hydrogen) vented somewhere safely away from the whole setup (H2 + O2 + big arc = explosion, afterall)

Pinky's Brain

Thu Nov 03 2011, 04:54PM

Registered Member #2901 Joined: Thu Jun 03 2010, 01:25PM
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Posts: 837

Dielectric barrier discharge is called silent discharge and is used in ozone generators ... that might be what "silent arc" is referring to.

Ocean Waves

Thu Nov 03 2011, 07:04PM

Registered Member #4181 Joined: Thu Nov 03 2011, 02:39PM
Location:
Posts: 42

corona and "silent arc" are the same, took some time for me to verify this, reading old txts is a lot like code breaking...........:)

Forty,
I would say your array of pins or or in my mind silver plated copper wires rather arranged on a circular mat inside of a glass cylinder, that has been chemically coated with silver on the outside and covered with conductive epoxy would be a good idea however, the questions are

How would one make a mat practically without soldering hundreds of bits of stranded copper wires onto a substrate and unraveling them?
What would be the best supply voltage / freq to produce the most corona?

The best i could think of was the fine mesh i used which does create a nice uniform corona discharge at all the edges of the mesh wire, all the way around i get a nice even glow, but I think what I might be lacking is power throughput as the glow is very dim and the eyes have to adjust in the dark for some time to see it, its not like to vivid photographable glow of say tesla coil.

seems to me that I have an ok discharge electrode I'm just not sure Im feeding it properly, I have tried feeding test sections of the same mesh and dielectric thickness as my olive jar with a FB xformer and a single mosfet driver. I can't get close lighting up as much surface area as my process electrode with the RF a 24 watt 10kv discharge from a 15khz FB only provides about 1 square inch of evenly distributed corona discharge, that equals the quality of my olive jar, but is much brighter more energetic. Using these ruff figures making some quick in the head calcs using about 50 square inches of electrode area on the olive jar, I would need a FB xformer that is producing about 1200 watts energize my olive jar electrode, thats a crazy amount of RF.

There has to be a point of best efficiency I'm just not sure how to find it

Conundrum

Thu Nov 03 2011, 09:29PM

Registered Member #96 Joined: Thu Feb 09 2006, 05:37PM
Location: CI, Earth
Posts: 4059

Maybe use some strands of 40 gauge clock wire laid down like a mat in an x-y grid?

Hopefully the insulation shouldn't be an issue, this sort of wire punches through almost instantly.

Forty

Fri Nov 04 2011, 05:17AM

Registered Member #3888 Joined: Sun May 15 2011, 09:50PM
Location: Erie, PA
Posts: 649

protoboard full of pins or just use a wire brush's bristles. for a circular array... i don't know, a bunch of wire brushes? I wonder if you could do something like this

to increase the surface area of your electrode with silver spikes
you could also try using a cw multiplier to get a higher voltage which may help to make more corona

Ocean Waves

Fri Nov 04 2011, 07:39AM

Registered Member #4181 Joined: Thu Nov 03 2011, 02:39PM
Location:
Posts: 42

Thats a cool idea but figuring out how to apply it over 50 square inches of a cylinder is a bit of a challenge. You have to control Ion flow, current density, equilibrium, and side reactions. I'll have to ponder on this silver idea for a awhile, and see if i can figure out a way to setup the cell to make it happen, going to have to purify some stock silver for sure, I think that copper in the mix would muck up the crystal growth.

Oh wait! I just realized only down side is silver would not make a very good discharge electrode as i think it is catalytically active against O3, I know it rapidly decomposes H2O2 as in jet fuel rapid, because silver is in fact an oxygen catalyst, which is always evident when melting silver, it absorbs a large amount of oxygen and at the moment of crystallization forces it out like a popping kernel of kettle corn, making a rather large eruption in the ingot at the last domain of fluidity where the oxygen is forced to during crystallization. I had mentioned silver for the inactive side of the dialectic, because of the common mirroring reaction that can be carried out on glass to for a nice perfect conductive layer.

Well a bit of searching and silver does in fact rise the the +3 state and clip O3

I wounder if there may be a way to use silver to catalyze the formation of O3, its so hard to find information on the catalytic properties of the PGM's and there isotopes, I find the isotopes the most exciting as they are like completely different metals in hydro and pyro with fantastic properties, however information on this topic is delving into the world of highly guarded trade secrets of governments and many evil corporations..............O3 formation catalyst?

Need another metal that forms nice sharp crystals, copper comes to mind but coppers formations are round and blunt as well copper corrodes to much, gold is obvious but I don't have that much of it, I do have some palladium sponge but its a hydrogen catalyst, and $500 an ounce but forms a nice nitrate salt. I actually don't yet have a good microscope, so experimenting on the small is not going to happen for me here.......

DC does not produce a silent arc except under special conditions, see wikipeda for "dielectric barrier discharge"

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