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Plastic to Oil – Produces 80% Oil

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Re: Plastic to Oil – Produces 80% Oil

#201

Post by HackOfAllTrades »

Why do people keep falling for this? This same fraud used to pop up only every 10 years. Now it's 5 or less.

I'm a PhD chemist. Please consider this: While plastics and oil are both hydrocarbons they have this important difference. Liquid hydrocarbons have short carbon chains and lots of hydrogen. Plastics have very LONG carbon chains, usually with many double bonds, and very little hydrogen.

That is why, when you heat plastic it decomposes into char -- as in charcoal. It is IMPOSSIBLE to produce oil, even theoretically, without adding a source of hydrogen.

A few centuries ago these same fraudsters would be selling you a way to change Iron into Gold.

Re: Plastic to Oil – Produces 80% Oil

#202

Post by hinkley »

ansible wrote: post #85

Sounds similar to the thermal depolymerization [1] developed by companies like Changing World Technologies. [2] That technology seems very promising, but they ran into a number of difficulties in practice. They build a plant to process turkey leftovers in Missouri, but the plant wasn't profitable, and the community complained about the smell. [1] https://en.wikipedia.org/wiki/Thermal_depolymerization [2] https://en.w…

I believe they started on the wrong foot. They cheaped out on the welding process and so the whole system was losing pressure and stinky volatiles. They had to redo their entire plumbing and people still complained after they swore up and down that there were no more leaks. which might be improper detection or people are used to a smell and don’t believe it’s gone.

Re: Plastic to Oil – Produces 80% Oil

#203

Post by overboard2 »

HackOfAllTrades wrote: post #201

Why do people keep falling for this? This same fraud used to pop up only every 10 years. Now it's 5 or less. I'm a PhD chemist. Please consider this: While plastics and oil are both hydrocarbons they have this important difference. Liquid hydrocarbons have short carbon chains and lots of hydrogen. Plastics have very LONG carbon chains, usually with many double bonds, and very little hydrogen. That is why, when you he…

Could you potentially do it with steam and the right catalyst?

Re: Plastic to Oil – Produces 80% Oil

#204

Post by Retric »

hinkley wrote: post #197
Retric wrote: post #161

Earlier quoted context omitted.

The dryer collects already loose or broken fibers in the lint trap for disposal. Air drying doesn’t which means those large broken fibers containing several orders of more magnitude more plastic than might escape from a dryer end up in the environment. This is why new clothes result in dramatically more lint than old clothes by weight.

The dryer abrades the fabric. If you have a delicate or dear piece of clothing they always advise that you air dry it as the fabric will last longer. Those delicate bags for the washing machine are substantially about limiting abrasion from rougher clothing, and also about not accidentally running them through the dryer by tucking inside or clinging to something else.

Normal use also abrades fabrics, the point is normal use doesn’t collect these damaged fibers so they all just end up in the environment.

Re: Plastic to Oil – Produces 80% Oil

#205

Post by cal85 »

HackOfAllTrades wrote: post #201

Why do people keep falling for this? This same fraud used to pop up only every 10 years. Now it's 5 or less. I'm a PhD chemist. Please consider this: While plastics and oil are both hydrocarbons they have this important difference. Liquid hydrocarbons have short carbon chains and lots of hydrogen. Plastics have very LONG carbon chains, usually with many double bonds, and very little hydrogen. That is why, when you he…

Interesting, thanks. As someone with little understanding of chemistry, can you clarify why "adding a source of hydrogen" is not possible/practical?

Re: Plastic to Oil – Produces 80% Oil

#206

Post by leeoniya »

ahmedk92 wrote: post #96
manbitesdog wrote: post #82

"This sounds too cool, let's check HN comments for the disappointment"

Before looking, it will probably be more pollution.

there was an infuriating segment on the local news last night that single-use/disposable coffee cups (e.g. keurig) are somehow "greener" because they supposedly use water/energy more efficiently than "traditional" ways of making coffee. of course, zero mention of where these things end up after their 15 seconds of fame.

https://wgnradio.com/the-business-of-food-with-steve-alexand...

it's like CO2 is the only impact to the environment that matters. you can always find greener ways to source the energy, but you're not going to find a lot of ways to reduce plastic trash.

Re: Plastic to Oil – Produces 80% Oil

#208

Post by godelski »

HackOfAllTrades wrote: post #201

Why do people keep falling for this? This same fraud used to pop up only every 10 years. Now it's 5 or less. I'm a PhD chemist. Please consider this: While plastics and oil are both hydrocarbons they have this important difference. Liquid hydrocarbons have short carbon chains and lots of hydrogen. Plastics have very LONG carbon chains, usually with many double bonds, and very little hydrogen. That is why, when you he…

Is it hard to add a source of hydrogen? In the images they have here it looks like there is a vat of water and it explicitly says it produces H2O and CO2 gas waste (though calls the CO2 harmless). That would imply there is a source of hydrogen here. (Not an expert, just legitimately curious so I can better spot snake oil)

Re: Plastic to Oil – Produces 80% Oil

#209

Post by aeroblade »

HackOfAllTrades wrote: post #201

Why do people keep falling for this? This same fraud used to pop up only every 10 years. Now it's 5 or less. I'm a PhD chemist. Please consider this: While plastics and oil are both hydrocarbons they have this important difference. Liquid hydrocarbons have short carbon chains and lots of hydrogen. Plastics have very LONG carbon chains, usually with many double bonds, and very little hydrogen. That is why, when you he…

You know, before tossing around your "PhD" in Chemistry maybe it'd be good to be sure you know what you're talking about first...

https://www.frontiersin.org/articles/10.3389/fenrg.2019.0002...)

https://cen.acs.org/environment/recycling/Amid-controversy-i...

https://www.sciencedirect.com/science/article/abs/pii/S01652...

Re: Plastic to Oil – Produces 80% Oil

#210

Post by zwkrt »

aeroblade wrote: post #209
HackOfAllTrades wrote: post #201

Why do people keep falling for this? This same fraud used to pop up only every 10 years. Now it's 5 or less. I'm a PhD chemist. Please consider this: While plastics and oil are both hydrocarbons they have this important difference. Liquid hydrocarbons have short carbon chains and lots of hydrogen. Plastics have very LONG carbon chains, usually with many double bonds, and very little hydrogen. That is why, when you he…

You know, before tossing around your "PhD" in Chemistry maybe it'd be good to be sure you know what you're talking about first... https://www.frontiersin.org/articles/10.3389/fenrg.2019.0002... ) https://cen.acs.org/environment/recycling/Amid-controversy-i... https://www.sciencedirect.com/science/article/abs/pii/S01652...

I don't know if you meant to, but all three of those links are hilarious if you read them. The first one has `moving toward` in the title, which is academic speak for "it doesn't work and we don't know how to make it work". Otherwise it would be arrived at. Very similar to Betteridge's Law of Headlines for academia.

The second link is a news article that is very critical about the motivations, projected success, and sneaky language used by companies to justify pyrolisys. And this is coming from what is ostensibly a pro-chemical news source.

The third article is paywalled and I'm guessing 99% of us can't read it. However, the `Opportunities and Challenges` is again academic talk for "we looked into it and it's really really hard".

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