Can we remake plastic into a rocket fuel?

Yes, that would be unusually cool to kill two birds with one stone: to contribute to protecting the environment from plastic waste + to produce high-quality fuel out of this waste. I have also heard about some companies who
develops necessary technologies. As far as I know their tests showed that using such fuel is even more effective than using kerosene✊
 
Oct 23, 2020
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I`ve read an article about green rocket fuel that was made by some private space company. This special type of rocket fuel because it is made from plastic waste. This company converts the following types of plastic waste: Polypropylene (PP). Polyester (PE).
Polystyrene (PS) and its mixtures and analogs
 

IG2007

"Don't criticize what you can't understand..."
I have the same question as that of Cat.

First of all, this is the first time I am hearing of such a fuel. It would be good and less detrimental to the environment. But, I doubt if plastics heavier (read that as *molecularily heavier) than light plastic bags can be made into efficient fuel.
 
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Catastrophe

"Science begets knowledge, opinion ignorance.
There is a further limitation to be considered. There are two types of plastic, thermosetting and thermoplastic. The thermosetting ones, as the name implies, "set solid". They will be destroyed by further heating. They cross-link so all the bonds are used up. They are like long strands with joins between the strands. I don't think these can be recovered???
The thermoplastic ones are just like the long strands. They don't join between themselves. In my opinion, these might have a better chance of recovery - but at what energy cost??

Cat :)
 
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IG2007

"Don't criticize what you can't understand..."
There is a further limitation to be considered. There are two types of plastic, thermosetting and thermoplastic. The thermosetting ones, as the name implies, "set solid". They will be destroyed by further heating. They cross-link so all the bonds are used up. They are like long strands with joins between the strands. I don't think these can be recovered???
The thermoplastic ones are just like the long strands. They don't join between themselves. In my opinion, these might have a better chance of recovery - but at what energy cost??

Cat :)
That's a point indeed, Cat. I agree with that. Will the plastic-fuel be able to be energy-efficient?
 
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Catastrophe

"Science begets knowledge, opinion ignorance.
"The plastic is subjected to pyrolysis and refining."

Well, pyrolysis means heating, and refining probably means distillation (more heat).

The question is - do you get out more energy than you have to put in? And don't forget all the cost of the equipment and the supervision (salaries) involved. I have a Chemical Engineering degree - that is my professional qualification.

Cat :)
 
May 11, 2021
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Given the right atoms you can convert almost anything into almost anything else. Peanut butter could be used to make diamonds as it contains carbon, but refining this raw material into pure carbon would be extremely bothersome and costly in both money as well as energy so its not practical. The same is true of many possible processes. I'm not sure if the plastic bags to rocket fuel conversion falls into this category or not. But I suspect it does.
 
Apr 18, 2020
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People are pointing out that the energy in the fuel would be less than the energy to produce it. Yes, of course. But you are forgetting the other benefit of this process, the elimination of tons of non-degrading plastic waste. Any cost/benefit analysis has to take both of these benefits into consideration.
 

IG2007

"Don't criticize what you can't understand..."
People are pointing out that the energy in the fuel would be less than the energy to produce it. Yes, of course. But you are forgetting the other benefit of this process, the elimination of tons of non-degrading plastic waste. Any cost/benefit analysis has to take both of these benefits into consideration.
I would like to turn your attention to post #17 of this thread.
 
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Apr 18, 2020
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I would like to turn your attention to post #17 of this thread.
I did see that. The comparison of the alternatives would have to include plastics recycling as well. Recycling of plastics so far has had limited success. Also the difference between thermosetting and thermoplastic materials, as Catastrophe (#18) pointed out.
 
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Jul 27, 2021
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I suggest that you would take more energy making the conversion than you would get out. My reasoning? 2nd Law of Thermodynamics.

Cat :)
Time crystal application and contribution to the space exploration needed purposes. 'Braking physics laws (especially 2nd Law of Thermodynamics'. Should make us faster and amazingly more effective.

Still, the plastic 'remake' is strong and vital vision/approach.
 

Catastrophe

"Science begets knowledge, opinion ignorance.
The best you can get is 'cracking' (term used in petrochemicals) down to hydrocarbons. No need to go right down to carbon. But don't forget
1. cost of old plastics and transport to plant
2. cost of plant itself, including all salaries for management and operators
3. heating costs in 'cracker'
4. re-delivering to end user, including packaging.
I guess (depending on which thermoplastics recovered) the yield might be 20%.

I really believe it would be truly uneconomic. Best recycle thermoplastics as suggested.

Cat B.Sc. (Hons) Chemical Engineering. :)
 
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Efficiency is a relative term. Strictly from the standpoint of fuel production, you can say that this process is relatively inefficient if there is another fuel production process that would make better use of the same energy input. You can say that it's absolutely inefficient, if you can show that, and also that energy in > energy out for the process itself.

From a broader societal standpoint, you'd need to also consider the relative cost/benefit of doing this vs. recycling or landfilling all that plastic. It may be that that would make it worthwhile, even if it wasn't the most efficient fuel production method.

Another efficiency consideration, for any of these cases, would be the cost of accessing the raw materials, which would be quite low for plastics.
 
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