How to turn plastic waste into diesel fuel cheaply

[rozier56]

rozier56

After my repack of the reflux column we had a good run.
We can safely run up to temp 320*c.
When we go higher in temp it tends to want to wax!
I will be installing a temp probe into retort in the plastic liquid next.
Also considering making the reflux column longer, maybe this will provide me more distillation time and less waxing effect. My current reflux column is 200mm wide and 500mm long.

[rozier56]

rozier56

Excalibur, thanks for your reply. I have done a new repack of the reflux column and will run early next week. Hope this helps.

[Excalibur]

I notice excalibur runs his retort and reflux at approx 380-390*C. My Question is that retort temp measuring the melted plastic or the vessel temp.
Further a question about the difference when melting WMO or plastic. The plastic will melt down to a oil that must be similar to the WMO OR NOT?
If so then the problem i am having of achieving a reflux temp 280*c with good liquid, although under diesel s.g spec.When the reflux temp is increased slightly i.e 290*c then we end up with a waxy product. We are running PE and pp.

Further we have tried to only start the water flow too the condenser only at the 208*C so as not to produce the lighter fractions early and distort the diesel fraction we are after.We have tried a reflux return system back too the retort in the beginning, but end up with a lot of water contamination as the steam generated is also returned, not all water goes out the reflux return exhaust.
Is wax produced only after one has produced the other petro products?

My temperature targets:
Retort = 380°C -420°C.
Reflux = 320°C - 350°C depending in the weight of diesel I'm aiming for.
These temps are for WMO as feedstock. Retort TC is in the retort liquid. Reflux TC is inside, quite near vessel exit.

Comparing WMO and plastic as feedstock at processing temperatures, they would appear similar consistency apart from color.

If there is wax in the finished product, it is not fully cracked. The heavy fractions that create the wax aren't being allowed to condense in the reflux and run back to the retort for re-cracking. You must discover the reason for this and correct it.

[rozier56]

rozier56

I notice excalibur runs his retort and reflux at approx 380-390*C. My Question is that retort temp measuring the melted plastic or the vessel temp.
Further a question about the difference when melting WMO or plastic. The plastic will melt down to a oil that must be similar to the WMO OR NOT?
If so then the problem i am having of achieving a reflux temp 280*c with good liquid, although under diesel s.g spec.When the reflux temp is increased slightly i.e 290*c then we end up with a waxy product. We are running PE and pp.

Further we have tried to only start the water flow too the condenser only at the 208*C so as not to produce the lighter fractions early and distort the diesel fraction we are after.We have tried a reflux return system back too the retort in the beginning, but end up with a lot of water contamination as the steam generated is also returned, not all water goes out the reflux return exhaust.
Is wax produced only after one has produced the other petro products?

[alejandroramallo]

You're right, my intention is to give a positive contribution when I can, although very small in comparison to yours. But beyond that, your posts are always very good, and it is a pleasure that people like you who go day to day in this and shares his experiences with us there are. Thank you. Best regards.

[wheels]

Hello wheels. Ethyl benzene and styrene have 2 different formulas. I am employed in a company that produces ethyl benzene and styrene. Beyond this detail, very good post

Yes you are correct. But it is too darn long and winded and complex to bother with on here, at least as I see it anyway.
Hi, welcome and great to see someone here that has some chemical knowledge. I am not a "Chemist", I just have a knowledge of the subject good enough to get me by in this game ;-) So am happy to stand for correction.

Styrene, C8H8 and can also be written as C6H5CH=CH2 is a derivative of Benzene C6H6.
Other names for Styrene are,
Vinyl benzene, cinnamene, styrol, phenylethene, diarex HF 77, styrolene, styropol, vinylbenzene, phenylethylene.

Ethylbenzene C6H5CH2CH3 or C8H10 can also be known as Ethylbenzol, Phenylethane and alpha-Methyltoluene.

Benzene C6H6 is Highly Toxic and a known High Risk Cancer causing Chemical. Ethylbenzene is naturally occurring and relatively safe.

Commercially, Ethlybenzene is mainly produced via a catalytic reaction of Benzene and Ethylene.

This is where I have made the mistake.
Styrene is made by Hydrogenating Ethylbenzene C6H5CH2CH3 → C6H5CH=CH2+H2

[alejandroramallo]

White expanded Polystyrene produces a clear liquid of Ethyl Benzene which is another name for Styrene.

Hello wheels. Ethyl benzene and styrene have 2 different formulas. I am employed in a company that produces ethyl benzene and styrene. Beyond this detail, very good post

[Excalibur]

Hi Farmhand
Yes, I've studied doublers quite a lot. I like the design that forces incoming vapor to bubble through the doublers' liquid contents. This would force heat exchanging to the liquid so driving the lightest fractions off.
It might just work and be sustained on the vapor stream heat which is quite relentless. Yes, the retort/reactor operating at 400°C+ there's a lot of heat!

It seem that interest in making fuel from waste plastic or oil has declined, no doubt because of low fuel prices. Just a matter of time before the next oil shock though.

[Farmhand]

Observing my plants' distillate flow in the sight glass have taught me a lot. In the early stages of a run the condensate is perfectly clear. As retort temperature increases the color turns to beautiful yellow amber. Push temperature higher has the color change to shades of red. Higher still has the color go to dirty brown opaque.
The trick seems to be, keep the flow coming at amber to lighter red. However the temptation is to crank up the heat because you want faster flow. Faster will work and even yield the correct weight but color will suffer.

In the moonshine industry they have what's called a doubler. Such a vessel is used to improve purity. In short the product stream is condensed and immediately re-evaporated. A series of doublers can improve quality in stages. I had thought about using similar technique but the downside is the cost of additional heat. Pondering on the subject I thought my vapor stream exiting the reflux could be quenched just enough to liquefy. Immediately it would be reheated to say 325°C subsequently re-evap'ing. This would be a form of double distilling...

I understand that you probably already know that the doubler or (thumper)
when used in distilling alcohol does not require an additional heat source,
the heat is provided by the vapor which is why it is so good to use a doubler
for increasing the purity of ethanol, the doubler is "charged" with a
reasonably high alcohol content liquid to begin with for best results.
A good reflux still can still produce a more pure product I think. However the
benefit of a double distillation done in one go with only the same one heat
source is very good for some. Sometime there is a big benefit from two
separate distillations as the wash can be treated with sodium bicarbonate
before the second distillation if desired.

Interesting topic this.

..

[wheels]

dear freinds did any one gone for pyrolysis of polystyrene if yes please share the experience

Yes I process it often. White expanded Polystyrene produces a clear liquid of Ethyl Benzene which is another name for Styrene. It has an Octane Number of 107
The issues you will run into is that a lot of Polystyrene in it's expanded form makes very little Fuel. So if you do a batch, a full retort produces very little fuel. If you melt the stuff down using acetone or even Petrol, to form a goop you will see what I mean by how much can be melted into such a small amount. But if you then fill the retort with that goop, you will produce a lot more fuel. Commercially, Polystyrene is crushed down in a huge Auger and so much pressure is applied that it heats and melts the stuff into a goo which squirts out the end of the machine like toothpaste, but on a large scale. It then cools into a solid to then be processed.
At 107 Octane, it will not run so well on it's own as a Petrol. But it can be blended with Petrol and will help raise the Octane but still remain in a usable level. Or you can blend it with Diesel and have it raise the Cetane Level.
Styrene (ethyl Benzene) is the proper solvent for Polystyrene and it dissolves the stuff quickly. So once you produce some, you can melt down more solid using what you produced.
Being a very lightweight fraction, you will need to cool the Gas output well so that you capture as much condensable liquid as you can, or you will lose most of it as Vapor.

[sunilkm153]

Polystyrene

dear freinds did any one gone for pyrolysis of polystyrene if yes please share the experience

[wheels]

Hello to everyone
We stop working due to bureaucratic obstacles.

Yes that is the single biggest issue for most of us trying to do this commercially. Especially now that many countries are working on trying to reduce Co2 levels. They would rather see Plastic buried in Landfills. Here in NZ, we have to have a thing called Resource Consent. It can cost tens of thousands and often in the Millions of Dollars and sometimes as long as 10yrs to work through the process and have the Bureaucrats tick all the boxes.

[kedigen]

Hello to everyone
We stop working due to bureaucratic obstacles. video link-related tests are below. If you're curious about something, I'm around.

1. home reactor https://www.youtube.com/watch?v=VlJZCBD8nt0
2. only paraffin https://www.youtube.com/watch?v=1xaq_oKcIqs
https://www.youtube.com/watch?v=kOscVDOy96A
3. finished https://www.youtube.com/watch?v=1Khn29RY1WU

[wheels]

And, we DIY petroleum crackers and refiners should stick to non-halogenated hydrocarbons.

Absolutely and a reason why I have always warned members to stay away from anything other than the two relatively safe plastics being PP and PE.
It's also one reason why I have never discussed with any great detail of what I do, being the destruction of these toxic plastics.
But besides the Toxic issues, none of these plastics are economical to process for fuels anyway. They are very low yielding and they require specialized equipment and design and far to much post processing to remove and dispose of the Toxic products.

[Beyond Biodiesel]

Yes, if I had a need for additional cuts/fractions, a series of pots is the way I'd be doing it and of course, do it while the vapor/condensate stream is hot...

BB's description of fuel produced from clear to amber indicates it was made at a rate it was happy to be distilled at, unhurried and allowed to proceed at the pace it wanted. Clearly we cannot apply unlimited heat and expect all to be well. Best to apply heat to closely match the requirements of the liquid we are distilling.

Yes the only way to do it in my opinion. The more control results in a more precise output range of Hydrocarbon.

I agree with wheels here. I find multiple pots equals more fractions, and more precise fractionations, which reduces boil-over, which produces a better product. The fractions can then be all too easily recombined later to produce whatever fuel I want, ie. diesel fuel. And, so far I have found no reason to boil-off light fractions up to 50% of the fuel blend

I have electric heating on all my pots, but so far have no used them. This is only because from the Catalyst onwards, my Plant takes a slightly different track than everyone else. Although my catalyst cracks, the main reason for it to be there is for removal of a specific chemical that is used in all Ewaste plastics as a fire retardant. If that is not removed, it causes all sorts of corrosive issues and is very toxic. Plus it retards combustion of the Fuel in the Burner. It will do the same in an engine and for such a reason, I have not gone too far down the path of using my Fuel in an engine just yet. I have done it to test if it works, but I need to do a great deal more work in that area to understand long term issues that may or may not arise. Anyway....
back to the story. So my Catalyst is heated to a very high temperature to initiate the conversion process and then the Vapor stream needs to be cooled dramatically before reaching the First Pot. But what I have found is that the Vapor arrives at the first pot at a suitable temperature and so I do not need to heat it again. A bonus because it save energy heating the Pot. That captures any heavy fractions and the vapor is allowed to flow to the second pot, where I am trying to rapidly get it down to a much cooler temperature before any "solvent" ranges flow on to the Chilled pot. If I allow to much heat to flow on into the Chilled pot, then the chiller can not cope and it gets too warm and I end up with a very light fuel floating on top of the bubbler water.
I am currently working on a new feed design and that will allow the continual feeding of the plant along with being able to process multiple plastic types separately, yet simultaneously and each type can have a particular process applied to meet their individual need. But it will result in a wider ranging hydrocarbon output that will need greater effort in cracking and containing.

As we have discussed earlier in this thread, cracking halogenated hydrocarbons is full of problems, especially toxic vapors that the operator is exposed to. I personally believe that halogenated hydrocarbons are so toxic that there should be a law passed that requires all halogenated hydrocarbons be returned to the manufacturer for disposal or recycling. And, we DIY petroleum crackers and refiners should stick to non-halogenated hydrocarbons.