Liquid Ozone as Oxidizer

[Sanic]

As we all know, liquid oxygen is the standard oxidizer for rockets in general. Ozone is oxygen with an extra oxygen atom, so why wouldn't it work even better? Logically, this makes sens, as more oxygen means higher combustion temperature. I have no idea where this is going, so I ask for your thoughts.

[sgt_flyer]

It has been considered before, but liquid ozone is much too unstable, due to the molecular bonds.

Ozone is not a stable molecule by itself, and can easily decompose - in an exothermic fashion.

Basically,in a O2 / O3 mix with more than 24% O3, an O3 molecule decomposing in O2 + O can trigger an exothermic chain reaction - and heating a cryogenically liquefied gas - you'll have to deal with a huge overpressure spike when that happens and boom

Edited November 11, 2015 by sgt_flyer

[Sanic]

It has been considered before, but liquid ozone is much too unstable, due to the molecular bonds.

Ozone is not a stable molecule by itself, and can easily decompose - in an exothermic fashion.

Basically,in a O2 / O3 mix with more than 24% O3, an O3 molecule decomposing in O2 + O can trigger an exothermic chain reaction - and heating a cryogenically liquefied gas - you'll have to deal with a huge overpressure spine when that happens and boom

Why not kerosene? Kerosene isn't cryogenic.

BTW thanks for the info.

[PB666]

It has been considered before, but liquid ozone is much too unstable, due to the molecular bonds.

Ozone is not a stable molecule by itself, and can easily decompose - in an exothermic fashion.

Basically,in a O2 / O3 mix with more than 24% O3, an O3 molecule decomposing in O2 + O can trigger an exothermic chain reaction - and heating a cryogenically liquefied gas - you'll have to deal with a huge overpressure spike when that happens and boom

https://en.wikipedia.org/wiki/Solid_oxygen#Red_oxygen. The octomer of oxygen is stable at advanced pressure, highly compact. The problem is storage and conversion back to O2.

[fredinno]

https://en.wikipedia.org/wiki/Solid_oxygen#Red_oxygen. The octomer of oxygen is stable at advanced pressure, highly compact. The problem is storage and conversion back to O2.

There was also a thread on it I made. Red oxygen has very little research done into it- we aren't sure it it is fully stable at normal pressure once formed, though it is meta-stable, at least to an extent. Hopefully, it would be, but it also would be incredibly expensive due to the conditions of its formation, meaning it will probably not ever be used for rocket fuel. Syntin has a similar problem with cost, though less severe.

[cryogen]

Ozone as a rocket oxidizer was studied in depth in the 1950's. In theory you could get 20-30 seconds increase in Isp from it, over plain oxygen. It's thought too unstable to be practical. Here's an excerpt from John D. Clark's Ignition!: An informal history of liquid rocket propellants, which is out of print (and currently sells for $2,904 on Amazon )

The future of ozone doesn't look so promising. Or, to be precise, ozone has been promising for years and years but hasn't been delivering. Ozone, O₃, is an allotropic form of oxygen. It's a colorless gas, or if it's cold enough, a beautiful deep blue liquid or solid. It's manufactured commercially (it's useful in water purification and the like) by the Welsbach process which involves an electrical glow discharge in a stream of oxygen. What makes it attractive as a propellant is that (1) its liquid density is considerably higher than that of liquid oxygen, and (2) when a mole of it decomposes to oxygen during combustion it gives off 34 kilocalories of energy, which will boost your performance correspondingly. Sanger was interested in it in the 30's, and the interest has endured to the present. In the face of considerable disillusionment.

For it has its drawbacks. The least of these is that it's at least as toxic as fluorine. (People who speak of the invigorating odor of ozone have never met a real concentration of it!) Much more important is the fact that it's unstable  murderously so. At the slightest provocation and sometimes for no apparent reason, it may revert explosively to oxygen. And this reversion is catalyzed by water, chlorine, metal oxides, alkalis â€â€and by, apparently, certain substances which have not been identified. Compared to ozone, hydrogen peroxide has the sensitivity of a heavyweight wrestler.

Since pure ozone was so lethal, work was concentrated on solutions of ozone in oxygen, which could be expected to be less dangerous. The organizations most involved were the Forrestal Laboratories of Princeton University, the Armour Research Institute, and the Air Reduction Co. Work started in the early 50's, and has continued, on and off, ever since.

The usual procedure was to run gaseous oxygen through a Welsbach ozonator, condense the ozone in the emergent stream into liquid oxygen until you got the concentration you wanted, and then use this mixture as the oxidizer in your motor run. During 1954-57, the Forrestal fired concentrations of ozone as high as 25 percent, using ethanol as the fuel. And they had troubles.

The boiling point of oxygen is 90 K. (In working with cryogenics, it's much simpler to think and talk in absolute of Kelvin degrees than in Celsius.) That of ozone is 161 K. On shutdown, the inside of the oxidizer lines would be wet with the ozone-oxygen mixture, which would immediately start to evaporate. The oxygen, with the lower boiling point, would naturally come off first, and the solution would become more concentrated in ozone. And when that concentration approaches 30 percent, at any temperature below 93 K, a strange thing happens. The mixture separates into two liquid phases, one containing 30 percent ozone, and the other containing 75 percent. And as more oxygen boils off, the 30-percent phase decreases, and the 75-percent phase increases, until you have only one solution again  all 75 percent ozone. And this mixture is really sensitive!

So, after a series of post-shutdown explosions which were a bit hard on the plumbing and worse on the nerves of the engineers, some rather rigorous purging procedures were adopted. Immediately after shutdown, the oxidizer lines were flushed with liquid oxygen, or with gaseous oxygen or nitrogen, to get rid of the residual ozone before it could cause trouble.

That was some sort of a solution to the problem but not a very satisfactory one. Twenty-five percent ozone in oxygen is not so superior to oxygen as to make its attractions overwhelmingly more important than the difficulty of handling it. A somewhat superior solution would be to...

(reposting my own comment from an older thread)

[More Boosters]

A somewhat superior solution would be to ...

A somewhat superior solution would be to what? We're on the edge of our seats here!

[lajoswinkler]

Pure liquid ozone is a nightmare. One of those things that doesn't need to be in a mixture with something to explode on its own. If you look at it judgmental, it will explode.

[SomeGuy12]

Near the end of Ignition, Clark concludes only one way forward makes sense. You can only get a little more ISP over LOX with exotic chemistry and it is enormously difficult to do, often trading off less fuel consumption of a very cheap fuel for a fuel that is difficult to contain and expensive.

Anyways, he describes how you can make a gigawatt nuclear reactor fit in the space the size of a desk. It's relatively straightforward, just a metal assembly made of high temperature alloys and rods containing high purity U-235. Relatively speaking, especially in the 1970s, making something like this was fairly cheap and easy. In space, such a reactor can be used fairly safely, long as you do it after the spacecraft that uses it is in high orbit or above. Nuclear thermal gives you 1000 ISP, which is impossible to do via chemistry, right off the bat, and you can do even better than that with nuclear electric or really exotic nuclear thermal.

[Nothalogh]

As we all know, liquid oxygen is the standard oxidizer for rockets in general. Ozone is oxygen with an extra oxygen atom, so why wouldn't it work even better? Logically, this makes sens, as more oxygen means higher combustion temperature. I have no idea where this is going, so I ask for your thoughts.

For an exotic oxidizer, I'd rather use Chlorine Trifluoride, at least it minds its own business when in properly passivated tanks and plumbing.

As for a fuel to match, I'd assume something ultra high energy, and equally satanic, such as Tetraborane.

Edited November 14, 2015 by Nothalogh

[Sanic]

For an exotic oxidizer, I'd rather use Chlorine Trifluoride, at least it minds its own business when in properly passivated tanks and plumbing.

As for a fuel to match, I'd assume something ultra high energy, and equally satanic, such as Tetraborane.

Isn't Chlorine Trifluoride the oxidizer in planned tripropellant engines?

[Nothalogh]

Isn't Chlorine Trifluoride the oxidizer in planned tripropellant engines?

The only ones I've seen proposed were Lithium, Hydrogen, and Fluorine

[radonek]

For an exotic oxidizer, I'd rather use Chlorine Trifluoride, at least it minds its own business when in properly passivated tanks and plumbing.

As for a fuel to match, I'd assume something ultra high energy, and equally satanic, such as Tetraborane.

Sure, ClF3 is much safer… about the same way two hungry lions are safer then three.

[Hcube]

For an exotic oxidizer, I'd rather use Chlorine Trifluoride, at least it minds its own business when in properly passivated tanks and plumbing.

Chlorine Trifluoride, at least it minds its own business

Does it really ? It either explodes on contact or ignites what it touches... Even when properly passivated with a coating on the tubes, it's not the kind of thing you want in a rocket... I'm pretty sure i'd prefer ozone ^^

[lajoswinkler]

Sure, ClF3 is much safer… about the same way two hungry lions are safer then three.

If chlorine trifluoride is two hungry lions, pure liquid ozone is a herd of lions with a serious bipolar disorder who haven't had a meal in a week. If one lion goes nuts, it triggers all of them to go nuts, too.

Does it really ? It either explodes on contact or ignites what it touches... Even when properly passivated with a coating on the tubes, it's not the kind of thing you want in a rocket... I'm pretty sure i'd prefer ozone ^^

It does. As fluorine, it stays peaceful when it's surrounded by a passivated, fluoridized layer because it can't react with those. Also it will not chemically react with teflon, although it might dissolve it if in liquid form and flowing aggressively against it. One could hold it in liquid form in a thick teflon bottle, refrigerated and surrounded by reducing scavenger materials to reduce any fumes possibly leaking through.

I'd work with ClF₃ over liquid ozone because liquid ozone is inherently unstable on its own. AFAIK only micro samples of liquid ozone have been prepared to investigate its properties. Bulk? A barrel? No way I'd get half a kilometre near it.

[Hcube]

If chlorine trifluoride is two hungry lions, pure liquid ozone is a herd of lions with a serious bipolar disorder who haven't had a meal in a week. If one lion goes nuts, it triggers all of them to go nuts, too.

It does. As fluorine, it stays peaceful when it's surrounded by a passivated, fluoridized layer because it can't react with those. Also it will not chemically react with teflon, although it might dissolve it if in liquid form and flowing aggressively against it. One could hold it in liquid form in a thick teflon bottle, refrigerated and surrounded by reducing scavenger materials to reduce any fumes possibly leaking through.

I'd work with ClF₃ over liquid ozone because liquid ozone is inherently unstable on its own. AFAIK only micro samples of liquid ozone have been prepared to investigate its properties. Bulk? A barrel? No way I'd get half a kilometre near it.

Wait, i thought it reacted badly and explosivey with teflon ?

Well, let's make everyone happy and forget this by all drinking a pint of good ol' hydrazine together, something we can all agree on ^^

[lajoswinkler]

[quote name='Hcube']Wait, i thought it reacted badly and explosivey with teflon ?

Well, let's make everyone happy and forget this by all drinking a pint of good ol' hydrazine together, something we can all agree on ^^[/QUOTE]

PTFE already has completely oxidized carbon atoms.

[IMG]http://pslc.ws/macrog/images/ptfe02.gif[/IMG]

There's nothing ClF[sub]3[/sub] can do to it, chemically. Mechanical disruption is another thing. It might be able to lodge among the chains better, loosen them up. I don't know that, it's not something one can easily predict.

[shynung]

[quote name='Nothalogh']For an exotic oxidizer, I'd rather use Chlorine Trifluoride, at least it minds its own business when in properly passivated tanks and plumbing.
As for a fuel to match, I'd assume something ultra high energy, and equally satanic, such as Tetraborane.[/QUOTE]

J.D. Clark's book [I]Ignition [/I] have a section covering boranes, and concluded that they are not only impractical to use, but also performs poorly, in addition to leaving deposits of boron trioxide (B2O3, a solid anywhere below 1800 degrees C) on engine components.

[Kryten]

With exotic fuels or oxidisers, you also need to consider whether there's an industrial base for it; if you select something nobody else uses, you've just put up your costs massively because you have to support all that infrastructure alone. Liquid fluorine works because bulk fluorine is common in industry; liquid ozone or chlorine triflouride, not so much. Edited November 16, 2015 by Kryten