Useful Reactionsâ„¢ - Smoke-free hydrogen combustion

[Gustavo6046]

Liquid fuel is already ecologic, but when combusting hydrogen where comburant is ozone instead of O₂ the results get quite interesting:

H₂ + O₃ = H₂O + O₂

It has a more powerful exotermic reaction (thermical output; 1286 kJ/mol, bigger than that of standard combustion reaction with comburent O₂, H₂ + e^- = H₂O + O^-), does not need one electron per reaction and oxygen byproduct can be used for life support.

Only... where did you put my ozone layer miner you borrowed for experiments? And why is the ozone layer this rarified after I gave it?

Bonus: CO2 + 2H2O = CH4 + 2O2, a reaction which can return CO2 from astronauts in the command module into O2 and methane, costing water and heat (it is endotermic, thermical INPUT)...

Edited August 1, 2015 by Gustavo6046

[MinimumSky5]

Ozone is a very unstable gas, and also highly toxic, so I don't foresee a future of ozone rocketry! Also, I don't understand your point of the hydrogen not requiring an electron, in a normal hydrogen combustion reaction, it doesn't need one.

[Gustavo6046]

I found another CO2 reutilizing reaction:

(reaction imagery courtesy of WolframAlpha)

Ozone is a very unstable gas, and also highly toxic, so I don't foresee a future of ozone rocketry! Also, I don't understand your point of the hydrogen not requiring an electron, in a normal hydrogen combustion reaction, it doesn't need one.

Normally it would involve two hydrogen molecules, which would make it double fuel cost:

In WWI Germans did instead included one electron in that reaction so that it only needed one single hydrogen:

H₂ + O₂ + e^- = H₂O + O^-

Edited August 1, 2015 by Gustavo6046

[ZetaX]

And why should those CO2-reactions occur¿ It's not enough to find a chemical reaction where the elements match (that's very easy), you need to find a way to actually get this done (the hard engineering part).

[Gustavo6046]

And why should those CO2-reactions occur¿ It's not enough to find a chemical reaction where the elements match (that's very easy), you need to find a way to actually get this done (the hard engineering part).

Anything can be done to reutilize the taikon...astronaut breath at the spaceship or even spacesuit (for infinitely prolongued EVAs without having to bring in a plant).

[Gustavo6046]

The reaction is endothermic so we have to bring the other components and heat it a little. Done? So it can be the easiest way of doing. Not enough?

Resistors make da heat from craft electricity and react the breath CO2 (filtered from the other gases somehow) with ammonia to make O2 and useful byproducts.

[NFUN]

The reaction is endothermic so we have to bring the other components and heat it a little. Done? So it can be the easiest way of doing. Not enough?

Resistors make da heat from craft electricity and react the breath CO2 (filtered from the other gases somehow) with ammonia to make O2 and useful byproducts.

"Heat it a little" is probably somewhat of an understatement. Thermodynamics is not on our side in this instance. As that is the methane combustion reaction in reverse, it would take as much energy as would be produced by burning methane with perfect efficiency, which obviously isn't attainable. In general, the less engineered and less complex the setup is, the lower the efficiency. In space, mass is everything, and it would be expensive to lug heavy reaction cells along for this purpose. It wouldn't really be necessary either, acting more as an inefficient battery than effective means of generating oxygen. Collecting heat is also a problem, as heat doesn't like to be concentrated, and intentionally retaining heat without, again, heavy ways to control it would probably end badly. Spaceships produce more heat than they know what to do with, and radiating it away is a better solution than using complex engineering to make it usable.

[lajoswinkler]

Liquid fuel is already ecologic, but when combusting hydrogen where comburant is ozone instead of O₂ the results get quite interesting:

H₂ + O₃ = H₂O + O₂

It has a more powerful exotermic reaction (thermical output; 1286 kJ/mol, bigger than that of standard combustion reaction with comburent O₂, H₂ + e^- = H₂O + O^-), does not need one electron per reaction and oxygen byproduct can be used for life support.

Only... where did you put my ozone layer miner you borrowed for experiments? And why is the ozone layer this rarified after I gave it?

Bonus: CO2 + 2H2O = CH4 + 2O2, a reaction which can return CO2 from astronauts in the command module into O2 and methane, costing water and heat (it is endotermic, thermical INPUT)...

First of all, any usage of the word "ecology" in this context is futile and erroneous. There are no ecologic(al) fuels. Ecology deals with counting fishes in a river and making statistics about number of fox offspring in a forest. You might call them environmentally friendly fuels. Hydrogen and ozone are certainly detrimental fuels, more than the public thinks they are.

Second thing, yes, those reactions are real, but they aren't useful in the context of what you're presenting. It takes an enormous amount of energy to make ozone and the gas itself is extraordinary unstable, meaning you can't store it or make it pure in bulk amounts because it would explode on its own. You can just make ozonized mixture by applying coronal discharge to oxygen.

What you'd save on reaction products, you'd pay with huge interest beforehand.

[Streetwind]

Yeah, both water and CO2 are absurdly stable and you need to kick them hard to get them to react together.

A more favorable process to make methane out of CO2 is the Sabatier process, which is CO2 + 4 H2 ---> CH4 + 2 H2O. Because H2 is so aggressive (and H2O so stable) this reaction is actually exothermic. You need very little energy input at all, just enough to drive a machine that can keep the process running in a controlled fashion (a Sabatier reactor). Who knows, maybe you can harvest the heat released and allow the machine to power itself.

In another step, you can then use solar power to electrolyze the water and receive O2 for breathing (or oxidizer for a methane rocket), as well as 2 H2 - which is half the input, and you can feed it right back into the process.

This does mean you need to carry a supply of liquid hydrogen along - or, if ISRU is an option (and not just recycling human waste CO2 for life support), you can locally source water and electrolyze it.

[Hcube]

I don't know why you guys are even discussing the specs of the reaction and the ecological aspect... Good luck with stocking ozone in the first place ! this alone makes it impossible/not viable. Not even talking about the fact that it is a toxic gas (and it smells!)

Edited August 1, 2015 by Hcube
typos, typos, ttypos... :P

[PB666]

Liquid fuel is already ecologic, but when combusting hydrogen where comburant is ozone instead of O₂ the results get quite interesting:

H₂ + O₃ = H₂O + O₂

It has a more powerful exotermic reaction (thermical output; 1286 kJ/mol, bigger than that of standard combustion reaction with comburent O₂, H₂ + e^- = H₂O + O^-), does not need one electron per reaction and oxygen byproduct can be used for life support.

Only... where did you put my ozone layer miner you borrowed for experiments? And why is the ozone layer this rarified after I gave it?

Bonus: CO2 + 2H2O = CH4 + 2O2, a reaction which can return CO2 from astronauts in the command module into O2 and methane, costing water and heat (it is endotermic, thermical INPUT)...

Theoretically, you could use polysulfide which has a high density and compressibility to scavenge carbon from CO2 and return the Oxygen (I can't imagine it working)

More useful is polyoxygen (red oxygen, 0₈) at very low temperatures can be compressed far greater than oxygen.

You can create this at room temperature at 10 gPa and then cool it to zero degrees K and compress it in a press to form a stable solid pellet that has a much higher density than compressed O2. In terms of oxidation capacity per weight this is the best, there are better per volume, like potassium dicrhomate embedded in sulferic acid (oxidation drops rapidly as pH rises). However give that sulferic acid is very dense as with the dichromate, not such a good choice. I suppose the best theoretical bi reactants would be H+ (proton) and H- (hydride) but given these will saturate quickly in any reasonable container you could only really keep them in a solute with other non-reactive stabilizers.

On a very long spaceflight into intersteller space I could see cryogenic storage of O₈ in pressed pellets that are then loaded into tanks, sealed from one end and coverted into O2 for long term oxygen supply. In space flight you really want your O2 fast, and so you need to push it with helium, you could readily push a solid oxygen through a fuel line.

[YNM]

That's why you always get oxidizer-rich engines folks. No wasted ions.

Other than that, ozone is going to be more expensive out of their instability AND toxicity. May as well have N2O4/UDMH for that !

Edited August 2, 2015 by YNM

[longbyte1]

Extracting ozone for rockets might murder our planet.

[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...

Here's what pure liquid ozone looks like,

http://labphoto.tumblr.com/post/32406799158/liquid-ozone-just-made-some-with-an-ozonisator

Edited August 2, 2015 by cryogen

[Streetwind]

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 )

That excellent book may be out of print, but you can get a PDF of it online for free as an educational resource. For example here from the Glendale Community College.

[Laie]

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...

I figured that putting a lid on ozone and increasing the pressure would be a Bad Idea. I didn't expect that it was even possible to get a reasonably pure sample.