How to turn plastic waste into diesel fuel cheaply

[rozier56]

Wheels,can you show us a picture of your system??

[Excalibur]

The way I see it is that the principle of reflux will work identically on either retort type. It seems reasonable to assume that the rotary kiln vapor outlet exits from one end at the center axis. The vapor stream outlet should then be inclined vertical and a suitable reflux vessel attached. Control over the subsequent fraction produced is by means of reflux vessel temperature so that heavy fractions are recycled back to the retort by gravity while suitable fractions as well as lighter ones are allowed to proceed downstream.

[wheels]

you are right about the process I achieve a perfect working seal for my kiln as I operate it continuously for nearly 50 hours processing about 700 kg of waste plastic for my rotary kiln size of diameter 100mm but here I wish to mention one important aspect of my process I don't use rotary kiln as premelting zone i got the plastic fully converted to vapour phase in the kiln itself and then pass the vapours through condensors with different temperature zones to get desired sp.gravity products but the product I get had large amount of carbon / may be uncracked particles in it for which I got the product centrifuged and after centrifuge i found 5-7% sludge in it and now the rest of the fuel is of good quality To aviod this problem of carbon / uncracked particles (also to avoid process of centrifuge) i thought a good online reflux will possibly mininize this problem

Firstly it is good to hear you have all those aspects of safety and I am also glad to hear you have some experience with the tyre's.

Carbon particles will not be uncracked Fractions. Carbon particles are solid particles of Carbon and can not be cracked. They should be part of the waste left behind after the process. To have them carry through the various stages will mean three possibilities.
You may have too much in the Reactor vessel and the level is overflowing through the system. Plastic and Oil expands a significant amount when heated and this needs to be allowed for. We discussed that vary scenario a page or two back re a possible boil over with Excalibur's oil pyrolysis. It would be worth going back a page and having a read. Which could also create another possible problem with a horizontal drum. It will mean the contents will not be able to be too high or it is going to make it's way through the outlet pipe.
Another possible is a Boil over. You could be getting the Plastic too hot and it is boiling and spitting solids up into the outlet.
And the last possible, the pipes maybe too small in diameter and you have too fast a gas stream which is blowing carbon particles right through. As part of my reflux vessel, I have a cyclone that allows any possible particles to drop out of the gas stream and mix with the Refluxed fractions to be dropped back into the reactor vessel.
The easiest course of action may be to build your own centrifuge filter and filter the Fuel as it exits. This would also allow the removal of particles you can not see. A centrifuge with a diameter of about 100mm spinning at about 6000RPM will remove particles down to about 0.1 micron. You can not see particles that small. But they will cause the Fuel to have a brown colour. Removal would clarify the Fuel to a very clear amber colour.

[sunilkm153]

BBD is quite correct and as I said earlier, the Reflux is just one way of cracking the heavier Fractions. If you are looking at processing 5000ltrs, then you are into a whole different realm and need to be looking at some very well engineered designs. I find this kind of situation concerning. Several of you on this Forum have gone from small operations to very large commercial scale operations in a single leap, with no real knowledge and no real understanding. If you knew what you were doing, the Reflux situation would not be a question you would be asking here. I don't think many of you are getting it. This can be a very dangerous operation. There have been people killed and entire towns destroyed with these machines failing. So for instance, have you considered what is going to happen with the Retort Vessel by rotating the vessel through the heat? In other words, the vessel is going to be constantly heating and cooling as it passes in and out of the heat. As that been considered and designed for?
What about the exhaust gasses? Processing 5000ltrs mean you will be expelling a lot of Gas to atmosphere. Are you just spewing toxins into the air or are you processing the Gases to expel a clean output?
And then my final question is, what about the Fuels produced. If you don't understand the Reflux process, then you don't understand distilling and I am concerned that you will have no idea about Fuel stabilization and specific weights and testing of fractions and so many other points, that commercial Fuel production s going to require.

dear friend wheelz
I am happy to see your genuine concerns about safety of process as well as peoples . in the same forum BBD also raised question fo safety several times
let me know you that since last three and half years I am working with tyre pyrolysis machine having capacity 10000 kg / day without any major problem here we use naked flame to heat kiln by burning wood/coal under rotary kiln the rotary kiln having diameter of 3000 mm rotating at 4 rpm is to be heated upto 550 degrees
AS your concern thermal expansion of the material is very well calculated before fabrication of kiln secondly exhaust gases are passed through scrubber with caustic solution and then stored in a gas ballon which is used for electricity generation through gas generator and after going through generator a second stage scrubber is also there to scrub exhaust gases from generator
finally if you think that by raising a simple question about reflux I don't have any idea about process you are wrong here you simply misunderstood my question I never asked about working of reflux I simply sought forums opinion about idea of ONLINE REFLUX for rotary kiln
lastly we never use this fuel as transportation fuel here we used this fuel as boiler fuel.

[sunilkm153]

you are right about the process I achieve a perfect working seal for my kiln as I operate it continuously for nearly 50 hours processing about 700 kg of waste plastic for my rotary kiln size of diameter 100mm but here I wish to mention one important aspect of my process I don't use rotary kiln as premelting zone i got the plastic fully converted to vapour phase in the kiln itself and then pass the vapours through condensors with different temperature zones to get desired sp.gravity products but the product I get had large amount of carbon / may be uncracked particles in it for which I got the product centrifuged and after centrifuge i found 5-7% sludge in it and now the rest of the fuel is of good quality To aviod this problem of carbon / uncracked particles (also to avoid process of centrifuge) i thought a good online reflux will possibly mininize this problem

[wheels]

Exactly right no amature DIY fellow gone for rotary kiln I myself initally using 50 ltr gas cylinder as vertical retort then we scale up the same configuration to 600 ltrs s s vessel having stirrer in it from one of my friends pharma industry
now I am planning to proceed towards 5000 kg / day processing capacity for which I find rotary kiln most suitable
we are going to process waste plastics not tyres
perfect seal ( gland/double mechanical seal ) at inlet and outlet both very well insured also air lock valves are used
To heat reactor/kiln we have a duel mode hot air generator consuming pyrolysis oil/pyrolysis gas
Is there any other simple and easier way to online crack heavier fractions for rotary kiln also

BBD is quite correct and as I said earlier, the Reflux is just one way of cracking the heavier Fractions. If you are looking at processing 5000ltrs, then you are into a whole different realm and need to be looking at some very well engineered designs. I find this kind of situation concerning. Several of you on this Forum have gone from small operations to very large commercial scale operations in a single leap, with no real knowledge and no real understanding. If you knew what you were doing, the Reflux situation would not be a question you would be asking here. I don't think many of you are getting it. This can be a very dangerous operation. There have been people killed and entire towns destroyed with these machines failing. So for instance, have you considered what is going to happen with the Retort Vessel by rotating the vessel through the heat? In other words, the vessel is going to be constantly heating and cooling as it passes in and out of the heat. As that been considered and designed for?
What about the exhaust gasses? Processing 5000ltrs mean you will be expelling a lot of Gas to atmosphere. Are you just spewing toxins into the air or are you processing the Gases to expel a clean output?
And then my final question is, what about the Fuels produced. If you don't understand the Reflux process, then you don't understand distilling and I am concerned that you will have no idea about Fuel stabilization and specific weights and testing of fractions and so many other points, that commercial Fuel production s going to require.

[Beyond Biodiesel]

dear friends
we all know reflux tower is supossed to be one of the important aspect of our DIY pyrolysis plant but everywhere we use reflux the reactor vessel was vertical stationery vessel
now my question is that how will we add online reflux tower if we had an horizontal rotating reactor vessel (horizontal rotary kiln)
in advance

If you examine a modern day petroleum refinery you will see distillation towers. At each fraction there is always something doing refluxing, such as bubble caps, etc.

In my 5-gallon (20L) pyrolysis unit I went horizontal, because it was easier than building and working on a 30 foot (10M) tall tower. There is essentially no reason why fractionation, which requires reflux, needs to be vertical, except for conserving real estate and energy, as heat rises so it can be used in a vertical tower situation, which it cannot be employed in a horizontal configuration.

Exactly right no amature DIY fellow gone for rotary kiln I myself initally using 50 ltr gas cylinder as vertical retort then we scale up the same configuration to 600 ltrs s s vessel having stirrer in it from one of my friends pharma industry
now I am planning to proceed towards 5000 kg / day processing capacity for which I find rotary kiln most suitable
we are going to process waste plastics not tyres
perfect seal ( gland/double mechanical seal ) at inlet and outlet both very well insured also air lock valves are used
To heat reactor/kiln we have a duel mode hot air generator consuming pyrolysis oil/pyrolysis gas
Is there any other simple and easier way to online crack heavier fractions for rotary kiln also

I find your rotary kiln idea novel and fascinating, but fraught with the technical challenge of maintaining a reliable seal in a high temperature environment. Nonetheless, if you can reliably accomplish this, then I still only see value in using a rotating kiln in the pre-melt zone of the plastic prior to injection into the retort. Because, once the plastic hydrocarbons enter the retort they will turn into a vapor, and move through your cracking medium (catalyst) as a vapor, and then enter your fractionation zone as a vapor, where the vapor stream passes through a series of refluxing zones where the fractions are extracted in liquid form, then removed and collected, which is otherwise known as a fractionation tower.

[sunilkm153]

Reflux is just one way of cracking the heavier Fractions. It's used in many of the amature plants because it is easy and simple. A Rotary Kiln is not something most backyard operators would be able to do. You will need to find another means of cracking those heavy fractions without a reflux vessel.
Are you going to be processing Plastic or Tyres.
Do you have a means of ensuring a perfect seal at the Exit pipe?
How do you intend to heat the Kiln Vessel?

Exactly right no amature DIY fellow gone for rotary kiln I myself initally using 50 ltr gas cylinder as vertical retort then we scale up the same configuration to 600 ltrs s s vessel having stirrer in it from one of my friends pharma industry
now I am planning to proceed towards 5000 kg / day processing capacity for which I find rotary kiln most suitable
we are going to process waste plastics not tyres
perfect seal ( gland/double mechanical seal ) at inlet and outlet both very well insured also air lock valves are used
To heat reactor/kiln we have a duel mode hot air generator consuming pyrolysis oil/pyrolysis gas
Is there any other simple and easier way to online crack heavier fractions for rotary kiln also

[wheels]

dear friends
we all know reflux tower is supossed to be one of the important aspect of our DIY pyrolysis plant but everywhere we use reflux the reactor vessel was vertical stationery vessel
now my question is that how will we add online reflux tower if we had an horizontal rotating reactor vessel (horizontal rotary kiln)
in advance

Reflux is just one way of cracking the heavier Fractions. It's used in many of the amature plants because it is easy and simple. A Rotary Kiln is not something most backyard operators would be able to do. You will need to find another means of cracking those heavy fractions without a reflux vessel.
Are you going to be processing Plastic or Tyres.
Do you have a means of ensuring a perfect seal at the Exit pipe?
How do you intend to heat the Kiln Vessel?

[sunilkm153]

dear friends
we all know reflux tower is supossed to be one of the important aspect of our DIY pyrolysis plant but everywhere we use reflux the reactor vessel was vertical stationery vessel
now my question is that how will we add online reflux tower if we had an horizontal rotating reactor vessel (horizontal rotary kiln)
in advance

[wheels]

Hi wheels thank you 4u reply.

I have also seen a vid at "https://www.youtube.com/watch?v=APlczT3YJ2I" biomass to liquid or fuel using microwaves. By the way what kind of fuel "oil" is that? Can that be converted to diesel? Or is it more like heating oil?

excuse my ignorance

Thank you.

Microwave is just one of several ways you can Pyrolyze. There are many ideas and systems built to melt plastics. But you can Pyrolyze all sorts of things and Biowaste is one. Microwave energy flip/flops Molecules at extremely high frequencies (i.e. very fast) and this creates friction. A Domestic Microwave Oven is tuned to use a frequency that is resonant to Water Molecules and heating the water in food is what cooks it. Microwaves for heating plastic is tuned to do just that. So instead of having a large Retort, they focus high energy Microwave at a small space and pass the Plastic or Biowastes through that Focus point and the energy instantly heats and vaporizes the material. The Hydrocarbon Products produced depends on what is processed. it doesn't make anything different to what a Retort vessel would with the same material. However, you can get slightly different cracking, because the Heating is for a very short time. So thus it can be more controlled.
Another principle is using Plasma. Basically an Electric Arc in an inert Gas, much like a Welding Arc. It produces intense heat and once again, a very small focal point that the Material is passed through and instantly vaporized. Both Microwave and Plasma are specialized expensive machines and you will find them in large scale commercial installations.
Other methods more similar to what we are playing with, use various ideas to solve issues, like making a process continuous and not having Carbon build up in the bottom of the Retort. But each method comes with it's own negatives as well, being mostly complexity and thus scale. For instance, Fluidized Bed reactors use Super Heated Sand and the Gas produced is blown back into the bottom of the Vessel and "fluidizes" the sand. The Plastic is introduced as granules and the hot sand melts it quickly. The gas boiling the sand like a liquid is blown up through the top of the reactor vessel and cyclones separate the sand from the gas and the Carbon from the Gas. The Sand is super heated again and dropped back into the bottom of the Resort to continue the process.
The big advantage of any of these commercial practices is speed and because the Hydrocarbons are heated quickly and for a very short duration, the type of Fraction can be controlled and this can be a big benefit to stability of the Hydrocarbon. Or in other words, it doesn't oxidize. They then use specialized Distillation processes, just like an Oil Refinery, to crack the Hydrocarbons into what is wanted and maintain the stability.

[wheels]

Hi wheels thank you 4u reply.

I have also seen a vid at "https://www.youtube.com/watch?v=APlczT3YJ2I" biomass to liquid or fuel using microwaves. By the way what kind of fuel "oil" is that? Can that be converted to diesel? Or is it more like heating oil?

excuse my ignorance

Thank you.

While we are on the subject of Plastics not to Pyrolyse, there is of course the PVC materials which we have discussed here before. But another rather obscure material, which is not really plastic, but could be considered as such, is Polyurethane. This is a difficult one to identify and there are several stocks of which it can come from and you can not tell by eye. The Polyurethanes that are bad are the ones that have had an Isocyanate Curative. When you melt Iso based Polyurathanes, they release vast amounts of Isocyanate and it can not be easily removed in any of the Backyard type Pyrolysis units. You need very specialised Filtering to remove it. Isocyanate is very Toxic and will make you very very sick, sometimes for the rest of your life. Even a small dose of it can cause severe Skin and Lung problems.

I will make another post about the Microwave system.

[piu.iuu]

I don't really think he knows what he has got. It's a bit of a stretch for him to be calling it Benzene with no testing and if he did test it, he would find it probably isn't Benzene at all. He has no temperature probe to know just what Temp he really has and he has a yellowish residue in the end tube, which is anybodies guess to what it really is. But even if it was Benzene, it is very little for the amount of PET he Pyrolysed. He may have moisture in the tube and that may have reacted to form something
PET ( Polyethylene Teraphthalate, or commonly known as Polyester, C10-H8-O4) Note the 4 oxygen molecules!! That is not good to have in the Retort.
PET is made in two ways. Hydroxyterephthalate and Ethylene Glycol via an Esterfication reaction, or Dimethylterephthalate and Ethylene Glycol via an Transesterification reaction.
You have to be extremely cautious pyrolysing PET. As you notice in the Video, it goes from a Solid to a Gas with no real liquid stage. It's melting point is about 260degC. Then you will notice it suddenly produces a large volume of Gas. That point is where the Acid decomposes at about 350DegC. The Gas is Terephthalic Acid and the danger with it is that as soon as the temperature of the gas cools below the 280degC point, it turns back to solid Terephthalic Acid which is a Whote Crystal. If that happens in any of the Pipe work or Vessels, it will simply block it all up with a White powdery material, being the Terephthalic Acid.
I guess in some countries, PET may be easy to come by, but in many Countries, PET plastics are sort after to make Polyester fibers and it is worth quite a lot of money.

Hi wheels thank you 4u reply.

I have also seen a vid at "https://www.youtube.com/watch?v=APlczT3YJ2I" biomass to liquid or fuel using microwaves. By the way what kind of fuel "oil" is that? Can that be converted to diesel? Or is it more like heating oil?

excuse my ignorance

Thank you.

[wheels]

Hi there

I have seen a vid: on youtube which a guy makes Benzene from PET and NaOH. Source ( https://www.youtube.com/watch?v=JhUxaNesnxs )

Any thoughts?

Thank you.

I don't really think he knows what he has got. It's a bit of a stretch for him to be calling it Benzene with no testing and if he did test it, he would find it probably isn't Benzene at all. He has no temperature probe to know just what Temp he really has and he has a yellowish residue in the end tube, which is anybodies guess to what it really is. But even if it was Benzene, it is very little for the amount of PET he Pyrolysed. He may have moisture in the tube and that may have reacted to form something
PET ( Polyethylene Teraphthalate, or commonly known as Polyester, C10-H8-O4) Note the 4 oxygen molecules!! That is not good to have in the Retort.
PET is made in two ways. Hydroxyterephthalate and Ethylene Glycol via an Esterfication reaction, or Dimethylterephthalate and Ethylene Glycol via an Transesterification reaction.
You have to be extremely cautious pyrolysing PET. As you notice in the Video, it goes from a Solid to a Gas with no real liquid stage. It's melting point is about 260degC. Then you will notice it suddenly produces a large volume of Gas. That point is where the Acid decomposes at about 350DegC. The Gas is Terephthalic Acid and the danger with it is that as soon as the temperature of the gas cools below the 280degC point, it turns back to solid Terephthalic Acid which is a Whote Crystal. If that happens in any of the Pipe work or Vessels, it will simply block it all up with a White powdery material, being the Terephthalic Acid.
I guess in some countries, PET may be easy to come by, but in many Countries, PET plastics are sort after to make Polyester fibers and it is worth quite a lot of money.

[piu.iuu]

This is an area where none of us have much experience. The plastics that easily pyrolyse into relatively simple fuels are polythene. polypropylene. and polystyrene. I have attempted to pyrolize a mixture containing PET and it was a disaster. Only a small proportion of the plastic converted into fuel.. The fuel was black and acidic, and therefore useless and the residue was also black, sticky and very acidic. My mild steel retort was damaged, as was my condenser. If I had used a scrubber containing a strong solution of sodium hydroxide I might have been able to reduce the acidity of the uncondensable gases but that would not have helped the quality of the fuel.
My advice, for what its worth, is to gain experience with the three plastics PE, PP and PS that pyrolize easily before trying to tackle the two more difficult and dangerous plastics PETE and PVC.

Hi there

I have seen a vid: on youtube which a guy makes Benzene from PET and NaOH. Source ( https://www.youtube.com/watch?v=JhUxaNesnxs )

Any thoughts?

Thank you.