News Energomash Develops Revolutionary Ammonia/Acetylene Rocket Engine

[orb]

RIA Novosti: Russia Develops Revolutionary Ammonia Rocket Engine:

Power engineering manufacturer Energomash has started development of a new rocket engine which could vastly reduce the cost of rocket launches and avoid the need to produce hydrogen for fuel, the makers say.

The new rocket, which will be around 30 percent more efficient than exising designs, works on a completely novel fuel mixture of acetylene and ammonia (atsetam).

“A mixture of acetylene and ammonia is 20 times cheaper than hydrogen as a kilogram of hydrogen costs about 2 thousand rubles ($67) and a kilo of atsetam is maximum of 100 rubles ($3.35)," Energomash's Director of Innovative Technology Anatoly Likhvantsev told Izvestiya newspaper.

"Using five to seven tons of this mixture, we can save a considerable amount of money. In addition, the components that are included in atsetam can be easily stored and transported, whereas hydrogen requires special storage and transportation conditions," he added.

The new atsetam engine will be assembled on the basis of the RD-161 oxygen and kerosene engine. The exact parameters will be determined during tests which will begin this year and will last for about three years.

The developers plan to launch rockets with the new engine in 2017-2018, dependent on funding.

Once the optimal ratio of acetylene and ammonia is found (in which fuel will be sufficiently powerful without exploding too easily) the designers will specify the parameters of the engine.

According to preliminary calculations, the atsetam engine will not require major structural changes to existing rocket motors since the physical properties of atsetam do not differ much from kerosene. An upper stage with the new engine will be installed on existing rocket carriers, which will be more profitable than developing an entirely new rocket with it.

{...}

 

[Urwumpe]

30% more efficient compared to what and by which metric?

There is a lot of carbon and nitrogen involved in the chemistry, does not sound like there is a high specific impulse to be expected, despite the large amount of hydrogen.

[math]n \cdot H_{2}C_{2} + m \cdot NH_{3} \rightarrow x[/math]

 

[N_Molson]

Yes, if they mean 30% better than Kero/Lox, that doesn't sum up. LOX/LH2 is still much better in terms of ISP.

But what I don't get is that current russian rockets don't use LH2 very much if at all ? :idk:

I'd say there is some confusion in the article...

 

[SiberianTiger]

But what I don't get is that current russian rockets don't use LH2 very much if at all ? :idk:

At present, none. In a future, a LOX/LH2 upper stage called KVTK will be employed for Proton and Angara.

 

[N_Molson]

I know, that's the masterpiece without wich my lunar landing mission would'nt be possible

 

[Urwumpe]

Just found out so much about the chemistry (sorry in advance: I am really poor in chemistry, I know all who didn't fail in chemistry in highschool already know so much about acetylene), that the acetylene decomposes into soot and hydrogen at more than 200 kPa pressure at room temperature, releasing a lot of energy in the process (So much energy that it is a direct explosive hazard). The pressure for decomposition drops with increasing temperature.

[math]C_2 H_2 \rightarrow 2 C + H_2[/math]
Mixing the Acetylene with nitrogen increases the possible pressure.

Because of that decomposition reaction, it also can't be turned into liquid.

Since Ammonia is a nitrogen compound, the question is: do they maybe mean dissolving the Acetylene in Ammonia and using it as propellant in combination with LOX? This would be really a fuel combination that could work as advertised, if the rocket doesn't explode.

EDIT: Found a patent about mixing Acetylen with Ammonia, I would say, it isn't unrealistic by that:

http://www.freepatentsonline.com/3574276.html

 

[N_Molson]

So, maybe a tripropellant (Ammonia/Acetylene/LOX) ? That would be interesting.

 

[Urwumpe]

So, maybe a tripropellant (Ammonia/Acetylene/LOX) ? That would be interesting.

No, still a Bi-propellant. But the kerosene would be replaced by liquid Ammonia under pressure with Acetylene (gaseous) dissolved inside it.

Pure Acetylene is always gaseous and can't be compressed to more than 200 kPa (2 times sea level pressure) at room temperature, and heating it to 160°C would already make it decompose and explode at sea level pressure, less temperature if the tank geometry permits local hotspots.

There is no way to turn Acetylene into liquid, without it exploding.

 

[N_Molson]

So Acetylene in Ammonia would be somehow like CO2 in beer :lol:

 

[insane_alien]

There is no way to turn Acetylene into liquid, without it exploding.

This is false, you can get liquid acetylene at temperatures around its triple point.(-80.8*Celsius and 1.27 atm) without much difficulty. the only problems come when it gets warm enough for ts vapour pressure to start exceeding 2 atm (you have some extra safety at the colder temperatures but would be foolish to rely on that).

at room temperature a liquid state is of course impossible to maintain.

 

[Urwumpe]

This is false, you can get liquid acetylene at temperatures around its triple point.(-80.8*Celsius and 1.27 atm) without much difficulty.

According to the safety information that I had read, it is impossible to achieve, since the Acetylene would decompose before reaching such conditions. Maybe this only applies to industrial methods and not laboratory conditions, for example by mixing the acetylene with nitrogen.

 

[boogabooga]

Ammonia? Ammonia?

Ekk gad man.

Have the Russians decided that they don't need Siberia anymore?

This is a disaster waiting to happen. Upper stage failure would potentially mean thousands of gallons worth of an ammonia cloud descending on earth. This isn't like hydrozine, etc. that we've seen before. Ammonia is a light gas that can cause huge problems in small concentrations.

I remember growing up near a chemical factor, where an ammonia leak was the biggest fear. The factory spent millions on early warning detection and alarms and we needed a community evacuation plan in case of even a moderate leak.

 

[Urwumpe]

Pardon, but you do know what ammonia is and in which quantities it is consumed in your country every minute?

Ammonia is far less bad than any Hydrazine, which could already harm you at small quantities. Ammonia is corrosive, but you can still smell the danger. When you smell UMDH, it is too late.

 

[boogabooga]

Yeah, I know what ammonia is. Also a cleaning fluid mixed with water in small quantities. But I don't think they use it for that too much anymore.

But there is difference between processing something on the ground in special tanks with safety precautions and blasting something into the sky at thousands of miles an hour.

UMDH is bad too, but I worry about the ability of ammonia to disperse/dissipate more, since it's a lighter gas. The area where you can "smell the danger" will be larger. And if you can smell ammonia, you're already in trouble, too.

 

[Urwumpe]

If ammonia vapors would be as bad as UDMH vapors, we would likely be already dead, because of the ammonia-based cleaning agents used by professional room cleaning teams. UMDH is BTW produced from ammonia.

When a rocket with a saturated (not sure if this would even happen) Ammonia/Acetylene fuel would crash intact (unlikely), it would be pretty likely that the fuel would combust violently. The crash would already be bad, the fuel explosion could even without oxygen assisting be much worse. But not toxic, only traces should not combust then.

The danger is not that ammonia is corrosive, the bigger danger is that 400 tons of such fuel would leave a lasting impression, even if you self-destruct the rocket early during ascent.