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Author: Subject: Pyrolyzing plastic waste: useful ?
metalresearcher
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[*] posted on 9-8-2021 at 02:34
Pyrolyzing plastic waste: useful ?


I stumbled upon this article. I believe in Plastics Pyrolysis, but more as a means to create 'crude oil' from it as a precursor to new plastics, not as an energy source. As this article says, it costs more energy to process plastic waste and refine the 'crude oil' to a useable fuel than the obtained fuel delivers.

https://www.lowimpact.org/pyrolysis-not-solution-plastics-pr...

The last sentence is the most striking, which I totally agree:

The elephant in the room is capitalism and the throwaway culture that the present version of this economic system has created – ever demanding new markets, more sales, more consumption, and more waste.

The best way to beat plastic waste is not producing plastic packaging unless really necessary (i.e. medical products).
But IMHO it is better to pyrolyze plastic waste for new plastic durable products with its (preferable renewable) energy cost than dumping it into the landfill or incinerating it.
Currently, plastic is the worst recycled material, compared to steel, aluminum, paper and even concrete. Plastic waste from the UK sent to be 'recycled' is piling up in Hongkong and nothing happens with it.

https://www.youtube.com/watch?v=oRQLilXLAIU

What are your ideas ?
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Belowzero
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[*] posted on 9-8-2021 at 02:52


Quote:

The elephant in the room is capitalism and the throwaway culture that the present version of this economic system has created – ever demanding new markets, more sales, more consumption, and more waste.


We are supposed to leave politics at the door but this just is a slimy and nonsensical oversimplified argument from a typical academic socialist.
Any other system ever implemented is way more wasteful and harmful to the environment (USSR anyone?!..)
Never compared to anything aka the utopian standard.


Apart from the simpleton politics, recycling plastic is a very good idea, perhaps solar energy that isn't used and not being stored can be applied for such a purpose.
It is quite annoying how amost anything is packaged in plastic, worst being the single use bags.
Biodegradable is probably a much smarter route.



[Edited on 9-8-2021 by Belowzero]




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[*] posted on 13-8-2021 at 10:53


Learn the concept of least bad option. Also, from achieving something, it is sometimes productive to move into damage control - whatever fails is not always total loss.

After that, the thing of pyrolyzing plastic into liquid hydrocarbons is a real and actual thing, and folks have used it to actually produce fuel for diesel engines and generators.

PVC can also be used to produce hydrochloric acid. I tested this and actually got a concentrated solution very quickly when the thermal decomposition took off. The reaction is autocatalytic once it takes off, so larger masses of PVC can cause issues if a runaway occurs. The smoke that pushed through, and the mess it left behind was a different concept. It also produces vinyl chloride, which is highly toxic, though, so severe caution should be taken.

[Edited on 13-8-2021 by Fyndium]
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[*] posted on 14-8-2021 at 06:29


Quote: Originally posted by Belowzero  
Quote:

The elephant in the room is capitalism and the throwaway culture that the present version of this economic system has created – ever demanding new markets, more sales, more consumption, and more waste.


We are supposed to leave politics at the door but this just is a slimy and nonsensical oversimplified argument from a typical academic socialist.
Any other system ever implemented is way more wasteful and harmful to the environment (USSR anyone?!..)
Never compared to anything aka the utopian standard.


Apart from the simpleton politics, recycling plastic is a very good idea, perhaps solar energy that isn't used and not being stored can be applied for such a purpose.
It is quite annoying how amost anything is packaged in plastic, worst being the single use bags.
Biodegradable is probably a much smarter route.



[Edited on 9-8-2021 by Belowzero]

The driving force of capitalism is "growth" and, on a finite planet, that's a problem.
No need to compare it to anything else.

Recycling is a better bet than biodegradation because the latter guarantees a waste of energy and materials.
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[*] posted on 21-8-2021 at 02:17


I did my PhD I the late 90’s on pp film and that was within a mat eng department with a significant smattering of polymer academics. There was heaps of money around even back then for developing uses for the recycled polymers.
I had a note up on my fridge for ages
Recycling-An expensive but virtueous process that converts waste than nobody wants into materials that nobody wants. esp plastics
I think, if I can recall it only takes 1% ish pvc in a polyolefin (hope, pp etc) to render most of the materials useful properties completely compromised.
I recently went on a bit of a rant concerning the bag name polymers were getting around the world as misplaced, we should be criticising ourselves these things are too frequently dumped back into any natural environment I’ll equipped to deal with something although largely innocuous chemical it’s negative mechanical affects are wide ranging. Also as some of many additives compounded with polymers (in order to gain greater usefulness) have notorious affects and they leach out often.
We need look no further than ourselves to blame really. Capitalism sucks, socialism is great, conceptually, we have never really been able to get it to work. Perhaps if Cuba hadn’t tried to house missiles for the ussr socialism may have been successful there. Who knows.
I don’t think its anti capitalism to advocate stronger regulation. In fact those decrying industry regulation are absolute hypocrites often because in highly regulated industries (ie cannot get more regulated than criminalising a molecule) they pander to governments.
As always the solution is simple baby boomers fucked everything up. They continue to stymie real progress, kill them all!!
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[*] posted on 21-8-2021 at 13:47


Here is an excellent article on plastic packaging. I didn't know of an approach to make cellophane moisture-proof prior to reading it, my expectation was that petrochemical-based films dominated market-share due to being much more moisture-proof, but looks like they dominate based on price:
Quote:
Cellophane dropped behind lower cost petrochemical-based films such as biaxially-oriented polyethylene terephthalate (BoPET) and biaxially oriented polypropylene (BOPP) in the 1980s and 1990s but it has made somewhat of a resurgence in recent times due to the fact it is biosourced, compostable, and biodegradable. Its sustainability record is clouded by its energy-intensive manufacturing process and potential negative impact of some of the chemicals used, but significant progress in recent years has been made by leading manufacturers in reducing their environmental footprint [1].


Yes I'm sure efficient recycling processes can be found for niche products, e.g. carpet. The problem is how the bean counters currently tally things. And I think changing how they tally things to include the ecosystem is they way to go [2][3].

Best not to get political, use more specific concepts than broad strokes on governance frameworks.




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[*] posted on 21-8-2021 at 14:30


Always avoid plastics where possible, should be a material of last resort not first attempt.



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[*] posted on 21-8-2021 at 22:42


Many polymers can be derived from plants, some are primarily derived from plants.

PLA, rayon, cellophane, nitrocellulose are primarily derived from plants
Polyethylene is relatively easy to make from fermentable compounds. (sugars -> alcohol -> ethylene -> polyethylene).
PVC can also be made from ethylene.

There are biochemical paths to nylon and many other plastics.

So in short plastics can be made from renewable resources, it just currently costs more.

If it can be made from biological sources, then biodegradation is possible.
There are bacteria that eat polyethylene, pvc is more difficult for them to break down but it can be recycled.

And of course most plastics are flammable. Sweden burns most of their trash.
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[*] posted on 22-8-2021 at 20:23
Plastic


Here where I live in Maine(USA) styrofoam food containers
and plastic straws are now verboten. Whether or not to
burn plastic ? It depends on many things. We have large
biomass electrical generation here already. I don't know if we
burn plastics as fuel.




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[*] posted on 19-9-2021 at 02:14


polyamide may under certain conditions (iirc 650*C+) produce HCN
PP/HDPE/LDPE may create "diesel"
polystyrene turns into styrene, useful as it can be oxidized into benzaldehyde over heated aluminium oxide catalyst with oxygen
melamine may be able to decompose into formaldehyde, actually certainly. if you ignite this plastic, you will smell formaldehyde. in the metal industry a white plastic is oftenly used for machining called "sustarin b" this also emits formaldehyde vapors when heated, iirc its close to melamine in composition




~25 drops = 1mL @dH2O viscocity - STP
Truth is ever growing - but without context theres barely any such.

https://en.wikipedia.org/wiki/Solubility_table
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[*] posted on 19-9-2021 at 06:01


Quote: Originally posted by Belowzero  


We are supposed to leave politics at the door but this just is a slimy and nonsensical oversimplified argument from a typical academic socialist.

Apart from the simpleton politics


The negativity in the original post was directed at wastefulness, whereas your negativity is directed at the poster and the "academic socialist" (this sounds shockingly anti-education by the way) whose article you certainly didn't even read, and uses unhelpful and unscientific language purely intended to insult. Not in any way an equal and warranted reaction. The knee-jerk assumption that any criticism of capitalism is somehow pro-Soviet is pretty "simpleton" too.

I'm hesitant to encourage simple pyrolysis as a primary means of plastics disposal because for many kinds of plastics, insidious and long-lived toxins like polychlorinated biphenyls and polycyclic aromatics are produced and must then be disposed of with even more care. I've not heard of accelerated decomposition (usually using bacteria or enzymes) posing this same problem but of course this is probably more expensive and can't be applied to all of the major plastics at this time. As renewable energy becomes cheaper and more widely available, I'd like to see more focus on UVC, ozone, or perhaps other chemical catalytic means that could be used to produce a consistent and useful byproduct of hydrocarbons or oxygenated derivatives. Or anything that avoids building LARGER, more difficult to process molecules as an unintended consequence.

[Edited on 9-19-2021 by Amos]
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