O2's effect on ozone generation

[Cosmo]

I've been messing around with ozone generators lately, and did a little experiment today, but am not certain as to what's actually going on.

I'm running 10kV from a neon sign power supply through stainless steel mesh screens affixed to either side of a pair of 2mm thick borosilicate plates. The space between the plates is approximately 1.5mm.
Both side edges of the plates have been sealed so the gas (CO2 & O2 respectively) have to travel through the arc.

In the first video, I'm forcing pressurized CO2 between the plates at 2 LPM.
You'll hear where I turn the gas on, and where I turn it off.
Note how while the gas is flowing, the arc seems to "disappear" to a large degree, and after turning the gas back off, the arc reappears quickly, starting from the open end of the plate 'sandwich' and working it's way back between the plates, filling the space with arc in about 1 second.

https://www.youtube.com/watch?v=5smWdW7K3Y0


In the second video, I'm forcing pressurized O2 between the plates at 2 LPM.
Again, you'll hear me announce "gas on" and "gas off".
The arc "disappears" again, but this time takes about 10 seconds to return to full arc.

https://www.youtube.com/watch?v=5smWdW7K3Y0


My questions are:

1.) What is causing the arc to "disappear".

2.) Why does the arc "reappear" 10x more quickly with the CO2 than with the O2?


I have some theories:

1.) A). The current is not as apparent, as the energy is directed at the O2 molecular fission.
B). The gas acts as a 'block' to the electrical current.

2.) Since it is O2 molecules that are ripped apart by the arc (creating O1 which bonds to O2 creating O3), the O2 fed plates take longer for the arc to "reappear" because the O2 molecules are absorbing the energy moreso than the CO2 molecules, the O2 fed plates take longer to finish fissioning.

3.) I'm a complete and utter wackjob and need to get a life.


Thanks ; )

[CanadysPeak]

Both videos appear to be carbon dioxide. Apart from that, I can't really tell what I'm looking at. Why only 10kV?

[Cosmo]

You're so right, I posted the same video twice, thanks!

As for "only" 10kV, that's the highest voltage I've seen in a portable generator. Most run 3kV - 7.5kV.

Here's the O2 link --> https://www.youtube.com/watch?v=w0ECgwNnx4U

[TheVat]

Oregon seems to be full of tinkerers, based on my anecdotally derived data, mostly acquired while living in the Valley for six years. We would go to DaVinci Days every year, a technology and innovation fair at the OSU campus in Corvallis, and have a great time as many of these tinkerers would come out of the woodwork (or the woods, or wherever they come from) and show off their brain children. Seemed like every third person I met in Corvallis (and Eugene, to a lesser extent) was fired up about science/tech the way you are, Cosmo. (again, my sample is highly suspect, bad, bad, science.

(sorry, this is the "derailing" that BioWizard warned about, and mods are supposed to set a better example)

So, to get more relevant to the thread, I'd be interested in getting a better general understanding of how different gases ionize, and how pressure and flow of gases affect this. There is much I don't understand about this experiment. I know that ozone forms near transformer stations, you can smell it as you go by, but have never been clear how the triatomic molecule is formed, in terms of how energy is input and how some O2 molecules are split up.

[Cosmo]

Funny how everybody thinks we're all a bunch of tree-huggers who wear grey wool socks under our Birkenstock sandals.
Hahahaha...
(There certainly are a lot who do though, it's not uncommon to run into a bushy-haired, wild-eyed oddity wandering through the woods with the above described footwear, fanny pack and plaid / untucked button-front shirt with a t-shirt under it sporting a marijuana leaf).

Exactly how the oxygen atoms are ripped apart from their O2 state is a grey area in which I'm not entirely fluent.
My speculation is that the energy that's required to do so is "absorbed" (for lack of a better term) in the process, decreasing the amount of arc between the plates.

After the straight oxygen flow has ceased, it takes several seconds for the O2 molecules within the space to be ripped into solitary atoms, at which point ambient air re-enters the space in the plates via the only direction it can (the open side of the plate which is in the 12 o'clock position in the video), bringing new molecules into the space at 1/5 the concentration (ambient air consisting of 21% oxygen), creating the rapid "trickle" of visible purple arc inward from the open side.

Either that, or... the O2 is actually blocking the arc somehow.
Light could be brought to this second theory by simply deducing the dielectric properties of O2.


Whadaya think?

[CanadysPeak]

You're so right, I posted the same video twice, thanks!

As for "only" 10kV, that's the highest voltage I've seen in a portable generator. Most run 3kV - 7.5kV.

Here's the O2 link --> https://www.youtube.com/watch?v=w0ECgwNnx4U

Thanks, but I still have no idea what I'm supposed to be seeing. Do you have any quantitative measurements?

I know you can make ozone at a few kV, but I would crank it up to about 20 kV (pretty easy to make) to really start to see something, maybe even up to 40 kV. What's special about being portable? As you might guess, I know nothing about this. I'm basing my questions on scrubbers.

[Cosmo]

In a nutshell, what I'm wondering is if one of the following is true (as they seem like the two possibilities here):

1.) High concentrations of O2 (in this case nearly 100%) act as a barrier between the plates, decreasing the electrical current that can pass through.

2.) The energy of the arc is being absorbed in the O2 molecular fission process.


Whadaya think?

[CanadysPeak]

In a nutshell, what I'm wondering is if one of the following is true (as they seem like the two possibilities here):

1.) High concentrations of O2 (in this case nearly 100%) act as a barrier between the plates, decreasing the electrical current that can pass through.

2.) The energy of the arc is being absorbed in the O2 molecular fission process.


Whadaya think?

Are you measuring the current? What are the values?

[Cosmo]

I'm not measuring the current.
I'm going by the visual as provided in the videos.

Perhaps the current doesn't decrease.
If that's the case, then why such a noticeable difference in the "purple sparkly"?
(I presume that the more current between mesh screens on a corona discharge plate, the brighter/louder the purply zappy sparkle).


It's cool man, I really appreciate your time on this.
I'm going to make an appointment with the chemistry professor at the local college at the local OSU campus.
I'll take the actual apparatus and show him; I'll post the results of that meeting here ; )

[BioWizard]

Hey Cosmo

Quick question. How many times have your repeated the experiment with CO2 and O2? Is the difference in time for the return of the arc statistically significant? Because if it's not, this could simply mean that there is a component in the air other than CO2 or O2 that is mediating the arc (could simply be particulates). Have you tried switching the positions of the tanks?

[BioWizard]

In other words, have you confirmed that your find is not an artifact of say the gauge for the O2 (or CO2) tank or the equipment etc? How confident are you that if someone else were to repeat this experiment in their own lab, they will get the same result?

As professional scientists, we obsess about experimental design, because the difference between making a meaningful find and a misleading artifact always boils down to your design. You need to get your controls down and make sure you test the null hypothesis before you dive into mechanistic interpretation. Also, when you share data with others, you really need to present it in a comprehensible manner that allows them to assess not only the recordings you made, but also the experimental design. P.s schematics can work wonders where words fail. I have to say this was not extremely easy to follow from first read, so I sympathize with CP :] (and I'm still not 100% sure I got it right)

[BioWizard]

By the way, I'm not theoretically opposed to the explanation regarding possible delay from residual O2 sucking up some of the current and delaying the return of the arc. You'll need to show 1) that the delay really is specific to O2 (relatively easy), and 2) that oxygen breakdown is necessary for it to happen (harder).

[Cosmo]

Hey Cosmo

Quick question. How many times have your repeated the experiment with CO2 and O2? Is the difference in time for the return of the arc statistically significant? Because if it's not, this could simply mean that there is a component in the air other than CO2 or O2 that is mediating the arc (could simply be particulates). Have you tried switching the positions of the tanks?

I've repeated the experiment several times, each with the exact same results.
1 second recovery with the CO2, 10 second recovery with the O2.

The space is air-tight and particulate free.

The gas enters the plates (sealed) from one side, expels on the opposite end, with the sides of the plate sealed.

[Cosmo]

In other words, have you confirmed that your find is not an artifact of say the gauge for the O2 (or CO2) tank or the equipment etc? How confident are you that if someone else were to repeat this experiment in their own lab, they will get the same result? 100% Yes, 100% confident.

As professional scientists, we obsess about experimental design, because the difference between making a meaningful find and a misleading artifact always boils down to your design. You need to get your controls down and make sure you test the null hypothesis before you dive into mechanistic interpretation. Also, when you share data with others, you really need to present it in a comprehensible manner that allows them to assess not only the recordings you made, but also the experimental design. P.s schematics can work wonders where words fail. I have to say this was not extremely easy to follow from first read, so I sympathize with CP :] (and I'm still not 100% sure I got it right)

I totally understand, which is why I'm going to seek the council of a live chemistry professor.
He/she can perform a hands-on experiment with me with the actual equipment, alter this and that as needed, etc.

[Cosmo]

By the way, I'm not theoretically opposed to the explanation regarding possible delay from residual O2 sucking up some of the current and delaying the return of the arc. You'll need to show 1) that the delay really is specific to O2 (relatively easy), and 2) that oxygen breakdown is necessary for it to happen (harder).

I getcha.

So if the O2 is 'sucking up some of the current and delaying the return of the arc", what is the reason? Is it because the energy is going into the fission process? Or is the presence of the nearly 100% O2 acting as a barrier, disallowing adequate transfer of the current?

That's primarily the two theories I'm going on here.
Open to an alternate theory as well, though no possibilities come to me.

[Cosmo]

Again, I can't thank you guys enough for taking your time to kick this around with me.
What I really need is an ozone level monitor, am looking for one online, not finding an option jumping out at me... but there has to be something available.

[CanadysPeak]

Again, I can't thank you guys enough for taking your time to kick this around with me.
What I really need is an ozone level monitor, am looking for one online, not finding an option jumping out at me... but there has to be something available.

If you're looking for ozone measurement, the inexpensive, and usually reliable, source in the US for gas measurement is MSA (Mine Safety Appliances).

[BioWizard]

I think you misunderstood what I said about particulates. My suggestion was that they were in the surrounding air. but forget about that, I realize in hindsight it was probably a dull thought, and my mind is now going in the exact opposite direction, so... Tell me something. Does the mesh get hot when it runs? And when you turn it on (without additional gas flow), does it immediately light up purple? Or does it take some time to come up in brightness? If so, how much time exactly? have you tried passing regular air through it instead of just CO2 or O2? Or a mixture of CO2 and O2? Does that take a time that's somewhere between 1 and 10 seconds?

[BioWizard]

My thought is that these things usually operate at a low pressure. The gas you're sending through it impedes the current. The question is why does O2 impede it longer than CO2, and I think your suggestion that O2 is somehow "absorbing" some of the current makes sense.

[Cosmo]

I think you misunderstood what I said about particulates. My suggestion was that they were in the surrounding air. but forget about that, I realize in hindsight it was probably a dull thought, and my mind is now going in the exact opposite direction, so... Tell me something. Does the mesh get hot when it runs? And when you turn it on (without additional gas flow), does it immediately light up purple? Or does it take some time to come up in brightness? If so, how much time exactly? have you tried passing regular air through it instead of just CO2 or O2? Or a mixture of CO2 and O2? Does that take a time that's somewhere between 1 and 10 seconds?

The surrounding air is incapable of getting between the plates, as one side of the plate has the sealed gas feed, the two sides are sealed off, and the third side (180° from the feed side) is where the gas exhausts.

The mesh stays relatively cool (ambient air temperature) due to fans blowing on/through the plates. The purple glow is the electrical arc from the DC current. It's like hundreds of tiny Jacob's Ladders.

It immediately lights up purple, yes, for as stated, the purple glow is the electrical arc.

I've tried passing ambient air, CO2, O2 and human exhale (blowing through the tube).

The results were not nearly as dramatic as with CO2 and O2, hence why we are sticking with those as the examples.
Also, we were not able to accurately meter the breath or ambient flows, whereas we were able to dial the CO2 and O2 in at precisely 2LPM.

Again, it's just a matter of the question:

1.) Does concentrated oxygen have electrical insulative properties that decrease the current's passing through it?

2.) During the fission of O2 molecules, does much of the electrical current become absorbed into that process, rendering less of the visual/audial of the corona discharge detectable by the eye/ear?


Those really are the questions here.

[Cosmo]

My thought is that these things usually operate at a low pressure. The gas you're sending through it impedes the current. The question is why does O2 impede it longer than CO2, and I think your suggestion that O2 is somehow "absorbing" some of the current makes sense.

The thing with the pressure difference, however, is that once we stop the gas from flowing, it's stopped, not slowed down to an eventual stop. When we hit "off", it's off.

I'm onboard with ya on the absorption theory, which leaves me with the next part of the question, what is the taking place during said absorption?
Could it be that the energy going into the molecular fission is being absorbed?

I believe that question can be answered by simply answering: Is energy created or absorbed during molecular fission, such as in the splitting of O2 molecules into single O1 atoms?

[BioWizard]

The surrounding air is incapable of getting between the plates, as one side of the plate has the sealed gas feed, the two sides are sealed off, and the third side (180° from the feed side) is where the gas exhausts.

When gas isn't flowing from the feed side, air comes in from the open end.

As for your subsequent question, when bonds break energy is released (as heat or radiation). But to break a bond, you need to put in energy (activation energy). That's why you need UV or electricity to make the ozone. You put in energy to break the O-O, which releases two free radical oxygen atoms which go on to bond with O2 molecules to make O3.

[Cosmo]

Bio, I'm aware of this.

My question is.

Is it the energy being used in the molecular fission that's causing the arc to be less intense?
I'll post what I obtain from my meeting with the prof.

I appreciate everybody's time.

[BioWizard]

Bio, I'm aware of this.

My question is.

Is it the energy being used in the molecular fission that's causing the arc to be less intense?
I'll post what I obtain from my meeting with the prof.

I appreciate everybody's time.

Perhaps I wasn't clear, sorry. I was suggesting that yes, it could very well be the case :] Especially if you can show that ozone is indeed being produced.

[Cosmo]

Thanks.

Ozone is absolutely being produced.
To the point of burning my eyes and choking me when I placed my face close to the plate.

With the discharge plate electrified for less than 2 minutes, the entire office space (5 rooms) was extremely odoriferous.


Thanks for your brain sharing!!

[BioWizard]

!!! You know that ozone is extremely poisonous, right?

[Cosmo]

I know that in high doses it can be irritating to the pulmonary system.

[BioWizard]

So Cosmos, how did your meeting go? What was the conclusion?

[Cosmo]

Darn it if I haven't heard back from the professor.

I'm thinking of abandoning the idea however, as I've found that if a piece of conductive debris gets caught between the plates it provides a "short" (of sorts), so the current, as opposed to being diffused across the span of the mesh, arcs straight across the plates at a single point, causing the plates to crack (despite the use of borosilicate [withstands 1300°C] or alumina ceramic) as the plate material.

I'm planning on continuing with the generator design, just wanted something that makes our generators 'special', as that is the foundation upon which I've built my company (inventing new, better products for the industry).


Thanks for asking!

[BioWizard]

Yeah you probably need a couple of HEPA filters in there.