How to turn plastic waste into diesel fuel cheaply

[Marso Green]

Thanks for sharing Mr. Woodgas. Care to explain the principle of your design? How are you planning to maintain those temperatures?

Thanks

[Beyond Biodiesel]

Mr. Woodgas, the baffles and the packing look very good. I have been exploring course to fine steel wools for packing, and am very happy with them.

Marso Green's question is a good one. I find that I like the idea of several stages of condensers, so that I can extract just motor oil, if I need it, or transmission oil, or diesel fuel, etc. On the other hand, if all one is doing is distilling WMO, then thinning it with gasoline to get the viscosity close to diesel fuel, then on trap might be all one needs.

Do keep in mind that there is the potential for toxic, corrosive, flammable and/or explosive exhausts coming from any pyrolysis/cracking/distillation unit, so one has to be very careful about what happens, and where the exhaust goes, and never operate one of these units in an enclosed space, and do make sure you have on hand a full-face respirator wit activated charcoal cartridge.

[Michael C]

Originally Posted by Beyond Biodiesel
I am well aware of the rotten egg smell of hydrogen sulfide gas, and I do smell H2S; however, that is normal for petroleum refining. This smell is sharp, and chlorine-like.

Adding ammonia to the bubbler is an excellent idea; however, just running my exhaust stream through a plain water bubbler has completely removed the stinging chlorine smell from my exhaust stream.

The take-home message here is, cracking and/or distilling plastics, rubber, and/or waste oils has hazards; one of which is the potential for flammable, toxic and/or corrosive emissions. It is all too easy to trap, condense, filter, dilute, and/or consume these potentially flammable, toxic and/or corrosive emissions. It is the responsibility of the pyrolysis/ distillation uni designer, operator to mitigate these potentially flammable, toxic and/or corrosive emissions. I do not; however, believe that just sending the exhaust stream into a flame is the best solution.

Well, it is possible that I have multiple acids being produced in my WMO distillation unit. So, far the simple water bubbler has eliminated all of the smells from my exhaust stream. However, I am sure there is a fair amount of flammable gasses in that stream that could/should be consumed with a flame.

I haven't followed this thread thoroughly but just want to add a couple of cents, my apologizes if this is already mentioned:

Ammonium are used in refining columns to inhibit corrosion, so injected at the top it also serves that purpose. By altering the pressurse within the column you can alter the proportions of the distilled fraction. Recirculating will refine in several steps and improve the purity of the product. You can burn the excess gas in a furnace, thereby getting some use of it. Preheating your raw material to get better work out of the column perhaps? You can make a simple flame filter out of pieces of flower pots or other ceramics in a sealed drum, a back-burning flame from furnace or torch will stop at that filter and protect the column.

H2S is a drag, it messes you up instantly in higher concentration. Beware of closed areas, you will drop down instantly just by opening a lid to a box containing the gas. No warning. As H2S is present, do not build any sealed boxes or rooms within your plant, with a lid easy to open without ventilating it first. I know of a technician who were to check a H2S meter situated in a box. A small leakage in the device filled the box with the gas. The very second he opened the lid, he fell to the ground. After rehab, his new job was to sort used bolts and nuts in 'usable' and 'scrap' piles.

[Beyond Biodiesel]

H2S is a drag, it messes you up instantly in higher concentration. Beware of closed areas, you will drop down instantly just by opening a lid to a box containing the gas. No warning. As H2S is present, do not build any sealed boxes or rooms within your plant, with a lid easy to open without ventilating it first. I know of a technician who were to check a H2S meter situated in a box. A small leakage in the device filled the box with the gas. The very second he opened the lid, he fell to the ground. After rehab, his new job was to sort used bolts and nuts in 'usable' and 'scrap' piles.

Good story for the wise to keep in mind. I was distilling 5 gallons of WMO that had brakleen in it. Brakleen is 80% TCE, which is a chlorinated hydrocarbon, so hen it cracks it produces HCL, which is actually worse than H2S, except H2S is also flammable. I nearly passed out 2 days in a row working with that sample. I have since bought a full-face respirator to wear whenever I am working on my pyrolysis unit. A face wash station adn chemical shower is also highly desirable.

[pravin]

H2s

I have a tyre pyrolysis plant. The gas or steam released upto 100 C is a real mess. It is very pungent odour, mixture of dust and gases. Can nyone suggest me a solution.

Secondly I tried polyester but the line was choked due to wax, any suggestion.

[Beyond Biodiesel]

Hi pravin, I am not sure what emissions of any you would find at only 100c, other than dirt and water, but the toxic by products of the pyrolysis of tires is mostly combustible gases, oil, and char products. This would include, and be most obnoxious, H2S (hydrogen sulfide gas). It is characterized by smelling like rotten eggs.

If you are not smelling rotten eggs, then the most likely other obnoxious smelling toxin is HCL gas (Hydrogen Chloride) This is bad stuff. It is an upper lung irritant. It also irritates all moist areas, such as eyes, nose and throat. Either toxic gas can take out the operator in seconds. So, a full-face respirator with activated charcoal filters is essential equipment for all operators of a pyrolysis unit.

There are a number of solutions to mitigating the various toxic, corrosive, and/or flammable by products of pyrolysis.
1) Trap and condense all condensable products. This means a water trap and ice trap.
2) Filter out all aerosols.
3) Water trap to trap all soluble gasses, such as HCL
4) Combust all Combustibles, such as: methane, propane, butane, and H2S; in a burner

[Marso Green]

Hi pravin, I am not sure what emissions of any you would find at only 100c, other than dirt and water, but the toxic by products of the pyrolysis of tires is mostly combustible gases, oil, and char products. This would include, and be most obnoxious, H2S (hydrogen sulfide gas). It is characterized by smelling like rotten eggs.

If you are not smelling rotten eggs, then the most likely other obnoxious smelling toxin is HCL gas (Hydrogen Chloride) This is bad stuff. It is an upper lung irritant. It also irritates all moist areas, such as eyes, nose and throat. Either toxic gas can take out the operator in seconds. So, a full-face respirator with activated charcoal filters is essential equipment for all operators of a pyrolysis unit.

There are a number of solutions to mitigating the various toxic, corrosive, and/or flammable by products of pyrolysis.
1) Trap and condense all condensable products. This means a water trap and ice trap.
2) Filter out all aerosols.
3) Water trap to trap all soluble gasses, such as HCL
4) Combust all Combustibles, such as: methane, propane, butane, and H2S; in a burner

Any reason to believe HCL is contained in tires?? I would agree with all of the above and would add that for successful burning of remaining uncondensable gases, one might try feeding into a biomass gasifier for complete cracking and useability towards heating

[pravin]

Thanks Beyond Bio and Marso Green,
Presently i am passing the fumes thru a scrubber but doesnt seem to be effective.

[Marso Green]

Thanks Beyond Bio and Marso Green,
Presently i am passing the fumes thru a scrubber but doesnt seem to be effective.

Pravin,

Could you please elaborate on your setup? I am suspecting that a lot of condensable gases are being wasted to the atmosphere in your process. Here are some questions that can help understand what is going on:

1) What size tyre pyrolysis plant are you operating? Is it one of the 10 TON per day plants?
2) What is the temperature at your condenser(s)?
3) Does the resulting condensate (fuel) also have an offensive odor?
4) What is the temperature of the gases as they enter the bubbler and as they are released to the atmosphere?
5) Is the odor coming out only up to 100 degree C and gone beyond that temperature, or is it starting at 100 degree C and remaining for the duration of the process?
6) what is the max temperature that your reactor has been reaching?
7) Have you tried the process with and without the scrubber as a way to measure the effect of the scrubber? Generally more than one scrubber are installed in series to completely clean up the fumes, and for higher efficiency with scrubbers, the larger the better
8) In order to burn the uncondensable gases, you need to pull the gases and mix them with air in a venturi burner head (using compressed air). You could also use fans to drive the gases but I believe that is unnecessarily complex and costly, not to mention messy.

That's a lot to answer but may help shed light on your problem

[pravin]

Thnx Marso Green
A) is reply to ur qustions.


1) What size tyre pyrolysis plant are you operating? Is it one of the 10 TON per day plants?
-- 5 t
2) What is the temperature at your condenser(s)?
-- inlet upto 350 c outlet 60 c
3) Does the resulting condensate (fuel) also have an offensive odor?
-- yes slight.
4) What is the temperature of the gases as they enter the bubbler and as they are released to the atmosphere?
-- max 150 c
5) Is the odor coming out only up to 100 degree C and gone beyond that temperature, or is it starting at 100 degree C and remaining for the duration of the process?
--starts @70 C
6) what is the max temperature that your reactor has been reaching?
-- 380 c
7) Have you tried the process with and without the scrubber as a way to measure the effect of the scrubber? Generally more than one scrubber are installed in series to completely clean up the fumes, and for higher efficiency with scrubbers, the larger the better
-- no
8) In order to burn the uncondensable gases, you need to pull the gases and mix them with air in a venturi burner head (using compressed air). You could also use fans to drive the gases but I believe that is unnecessarily complex and costly, not to mention messy.
-- after 180 c we get combustable gas.

phew a long one but very necesasry.

[pravin]

Polyester

I tried polyster in my reactor. It formed a wax layer thruout the condensate and reflux. One more interesting point the reaction was very rapid above 250 C upto 350 C, almost uncontrolable.
Has anyone experienced it.

[Beyond Biodiesel]

You have multiple problems with your design, pravin.

1) Your exhaust gasses should be at 0c before leaving the last condenser, or otherwise you are wasting valuable fuels.
2) This means your exhaust gasses will enter the bubbler at 0c

In conclusion you really need to work on your condensers. When you get them working properly you will have a lot more valuable fuel extracted from your pyrolysis project.
Here is a photo of me wearing a full-face respirator, which I believe every pyrolysis operator should have access to:

[ahraz]

fuel from plastic waste

hii sir,
i m doing this for my project. i just want to know that how to make non-oxygen enviorment in the chamber..

[Beyond Biodiesel]

hii sir,
i m doing this for my project. i just want to know that how to make non-oxygen enviorment in the chamber..

The simplest way to create an oxygen-free environment in a chamber is to first make sure the chamber is leak-tight by pressurizing it, then spraying soapy water into all of the joints. If no bubbles form, then it is leak-tight. Then purge the unit with CO2, and keep that purge going throughout the heating cycle.

[pravin]

Thnx Beyond Biodiesel and Marso Green,
I passed the gases thru 2nd scrubber and bubbler. If any remaining gas was charged thru the burner and burned out. Yppe no smell at all.