How to turn plastic waste into diesel fuel cheaply

[mjohnson1]

I expect there is a tendency for single-ingredient catalysts to preferentially react with particular molecular lengths. But could it be said that most catalysts will cut whichever hydrocarbon molecule bumps into it?
I am after the diesel fraction. So if I want to minimise the off-gas and naptha fractions wouldn't I add the catalyst to the retort / reflux column only after all the fractions down to diesel have been distilled off? I will use WMO as feedstock so I only need to boil / distil off the fractions down to diesel, then add the catalyst to the system to cut the remaining longer oily molecules into shorter ones. This way I prevent my target fuel profile from bumping into the catalyst and being cut into naptha and off-gas.
Does that sound reasonable?

That would be a very inefficient way of going about it as you would need to cool down your reactor once you want to add in your catalyst. Adding in a catalyst while the system is running complicates things.

Your best option is to find a catalyst that gives you the fuel profile you're looking for. Or like imakebiodiesel mentioned you can mix and match various catalysts.

[Ron Hammar]

HI ALL,

I just came back from a scrap yard and got 2 rear brake drums that have disk rotor and a drum for the emergence brake. I am going to use them for the opening of my boiler to add my plastic into the unit. The drum has a inside lip on it about a 1/4" hi and what I was going to do was take it to a brake shop and have them turn it down on their brake machine. Have them take off the lip on one drum with a 45* angle on it and then drill holes through the rotor for my bolts. This will make it so when I put the bolts on and nut them down the one drum will be pulled down into the other and should seal it. This is a simple way to make it like Jetis seal. It cost about $5.00 for it all.

[Ron Hammar]

Mjohnson1,
I am wanting to make gasoline and would like to know just what type of catalysts is it that you use to get this?

Thank you

I finally got around to testing out a batch of my new catalyst and I wanted to post my results here-

Conversion rate:73% to liquid fuel (have no way to measure noncondensable gasses but significant "smoke" was coming out)

Fuel composition-
89.5% gasoline
8.9% kerosene
1.6% diesel

No waxes.

This is far from ideal as I want a conversion rate to fuel of ~90% with the remaining ~8-9% to be gasses to power the unit.

[rozier56]

Derek

Hi jetijs,did you ever think you would spawn something this big? Well done to you and all the contributors.
it has been two weeks of intensive reading and taking notes.
NOW I WILL START TO LAUNCH MY PROJECT BUILD!
What determines a junior/senior member?
Hope to contribute some positive news to this thread.

[imakebiodiesel]

Col, your idea is an interesting one and may work with wmo if you can switch to catalysis without having to reheat. Perhaps a retort with 2 reflux columns one with catalyst and one without. Once the process has gone far enough without catalyst switch over to the other one.
However this may not work with plastic as thermal cracking alone produces mostly wax and gas.

mjohnston1 commercial FCC is incredibly active and even after it is "spent" by refinery standards it would overcrack in our process. However it could be a useful starter ingredient in small amounts. Natural zeolites and similar minerals would be classed as medium activity, air dried clays as low activity and fired clays as very low activity. A mixture of these will produce a catalyst with the profile to suit what you need.

[mtrans]

HI ALL,
I just came back from a scrap yard and got 2 rear brake drums

Not easy to weld,in my case.

[Col]

Target fuel profile and catalyst preservation

Hi IMBD
That's along the lines of what I was thinking, thanks! Might still be able to use just one refluxing column - by using simple valves I could redirect the vapours through the catalyst chamber then back to the refluxing column if it was set up right.

[Col]

Adding catalyst part way through, as above

Hi mjohnson1, does that sound ok to you? Do you see any complications with this? (aside from the extra heat sink of the catalyst chamber being introduced to the system part way through a batch, I guess I should pre-heat the catalyst chamber).

[Col]

catalyst to suit desired fuel profile

mjohnston1 commercial FCC is incredibly active and even after it is "spent" by refinery standards it would overcrack in our process. However it could be a useful starter ingredient in small amounts. Natural zeolites and similar minerals would be classed as medium activity, air dried clays as low activity and fired clays as very low activity. A mixture of these will produce a catalyst with the profile to suit what you need.[/QUOTE]

Hi IMBD - sorry to ask you to spell it out but do we need a percentage of our catalyst to be a highly active one to get the cracking started, and then let the less active catalyst/s take over? or can we just use 100% of any catalyst and have more patience? (and use more heating fuel in the process).
Does the 'activity' of a catalyst refer to the SPEED of the resulting cracking process or the LENGTH OF CARBON CHAINS the cracking reaction will produce when using that particular catalyst?
As I am after diesel I expect I could just use 100% fired clays, stated as having very low activity, and condense the longest possible chain lengths depending on my reflux temperature. Obviously an oil molecule cut into a diesel molecule will also produce an offcut of naptha or gas as a by product so yield of these shorter molecules will also increase.
Thanks!

[mortimer.dan]

Polypropylene Recycling to Fuel

Dear Sir, Thank you for your great information report in Pyrolysis of waste plastics. I am keen to hear if you have any more experience recycling computer plastics, does this extend to old tv plastics. How does one test a plastic to see if it indeed polyproplene, do you know if there is any easy test. You mention brittle plastics, is this a good general test. A lot of plastic storage boxes break and are discarded, are these potential for the plastic to fuel. Thanks Daniel

[imakebiodiesel]

First let me say that almost all my experience is with waste plastic so it may not apply with wmo.
Operating valves in the hot zone of a processor will be problematic. If you have 2 reflux columns you can place the valves near the condenser so that they are always cool. You can preheat the reflux using an electric band heater.
Low activity catalyst take time to activate but last a long time before they are spent. A small amount of a high activity catalyst starts to work immediately and by the time it cokes up the other catalysts will have started. Clays have a wide range of pore sizes and so will crack a range of molecule lengths. Zeolites including synthetic ones (FCC) have a single fixed pore size which will crack a very narrow range of molecules. In fact they are designed to do exactly that.

A warning about using naphtha as gasoline. As a test last year I ran my petrol powered 2 stroke brush cutter on naphtha+two stroke oil. The mitsubushi engine ran reasonably well aside from a small loss of power and slightly uneven idling. There was a slight knocking on deceleration but not severe, or so I thought. The motor seemed to run a bit hotter.
After about 100 hours use the motor refused to start and I stripped it down to have a look.
The engine had begun to seize and there was severe damage done to the piston, 2 stroke engines do not have valves but the hot running had damaged the edges of the ports. In a 4 stroke engine the damage to the valves would have been more severe and caused trouble sooner. Naphtha is not a replacement for gasoline, it is very low octane and will cause knocking and overheating which will damage your engine. At most, a 25% blend of naphtha in gasoline might be acceptable but dont try it in an expensive new vehicle.

[mjohnson1]

Ron Hammar

I don't wish to specify what catalyst i'm using since it took me months of trial and error and many hours of research to find a catalyst that works and is cheap.


Col

I would go for a simple approach especially on a small scale unit. Unless you are a great metal fabricator I would avoid your idea of the double valves. In addition, I've never seen the double valve idea attempted before so that leads me to believe it won't work great. Start small and simple.

mortimer.dan

Real simple. If it floats on water, use it. If it doesn't, don't use it.

Make sure you're using a small flat piece because a boat made out of pvc will still float.

[Mostafagaga]

can it being project ?!

Do you put the gases tube in water directly like blest company of japan , or use an condenser for cooling?!

Is this could be a business, or is it for the purpose of science

In my country we suffer from a lack of those resources, is it equivalent to the original petroleum product can we use and even be a draft?!

[Mostafagaga]

so i know friend that told me you have to put bentonit calcium nothing else with wast plastic in reactor ?? is this true or its not good ?

another thing he told me also to get high temperature , i put the reactor in car oil and put them on fire and it will high temperature in the reactor ?!! is that also true or what ?!

[lowriderzzz]

shredding machine to cut big plastic in peaces

Here is a drawing of a simple shredding machine you can even DIY that will cut big plastic waste into smaller chunks.

It is similar to those that cut tree branches and waste garden plants.