How to turn plastic waste into diesel fuel cheaply

[mjohnson1]

lowriderzzz

Your pipe coming out of the top of the retort is pretty small. It looks to be half an inch or so. I would run a 1" pipe to be safe.

If you're after diesel you will need to keep your reflux column hot the entire time to avoid the diesel fractions condensing in it and dripping back down. Do you have heating elements for that?

Right now your reflux column is at a ~90 degree angle to your retort. Fuel would drip down the retort and fill it up until it reaches that small pipe coming out of your retort. Someone else can chime in here but I believe you want to have the reflux setup directly over your retort so the stuff that condenses in there drips back down into your hot retort running at cracking temperatures.

I feel the condenser/reflux is too large for that small retort unless you are able to add feedstock continuously.

I don't see a purge gas setup or an inlet for a purge gas. If you plan on adding plastic continuously you will need that. CO2 or N2 are recommended.

You'll need at minimum a thermocouple and a way to read the output. I suggest a PID controller with your thermocouple if you're heating using electric.

I run my retort at ~450C and I use a catalyst in the liquid phase. When I load my retort I put in a thin layer of catalyst at the bottom, fill it with plastic and then top it off with more catalyst then a bunch of stainless steel pot scrubs.

Once your retort is up to cracking temperatures it will take ~5 minutes before you see the first drips providing your reflux isn't too cold.

[jonathan]

retort purge

l was thinking l have a machine to put gas in water l dont remember its name but it has co2 gas cylinder it is good for purge retort if yes how system work? l meant you have to leave gas always open or you have to open co2 before stoping heating retort? thanks

[lowriderzzz]

lowriderzzz

Your pipe coming out of the top of the retort is pretty small. It looks to be half an inch or so. I would run a 1" pipe to be safe.

If you're after diesel you will need to keep your reflux column hot the entire time to avoid the diesel fractions condensing in it and dripping back down. Do you have heating elements for that?

Right now your reflux column is at a ~90 degree angle to your retort. Fuel would drip down the retort and fill it up until it reaches that small pipe coming out of your retort. Someone else can chime in here but I believe you want to have the reflux setup directly over your retort so the stuff that condenses in there drips back down into your hot retort running at cracking temperatures.

I feel the condenser/reflux is too large for that small retort unless you are able to add feedstock continuously.

I don't see a purge gas setup or an inlet for a purge gas. If you plan on adding plastic continuously you will need that. CO2 or N2 are recommended.

You'll need at minimum a thermocouple and a way to read the output. I suggest a PID controller with your thermocouple if you're heating using electric.

I run my retort at ~450C and I use a catalyst in the liquid phase. When I load my retort I put in a thin layer of catalyst at the bottom, fill it with plastic and then top it off with more catalyst then a bunch of stainless steel pot scrubs.

Once your retort is up to cracking temperatures it will take ~5 minutes before you see the first drips providing your reflux isn't too cold.

Thanks for the comprehensive feedback. I'll try my best to modify the units as what you say.

The reason the pipe from retort is 90 degree to the reflux is because if I let go straight at the bottom, then the catalyst will be dropping down the retort ( i don't know what result this will have).

The condenser is met to be water cooled with inner pipe that runs water in it.

By purge gas do you mean the gas going out the bubbler ? I'll take care of this as well ( I still don't have the bubblers ready but it will have an outlet for them on the condenser column).

The retort I plan to heat with fire (either LPG gas burner, or some sort of turk burner). As far as for the reflux - do you think electric coils heating will do the job to maintain it at required temperature which is... actually how much it should be ?

What do you mean by catalyst in the liquid phase? Do you put it straight in the retort. If so, what for do you use your reflux column ?

Thanks once more time

[sunilkm153]

aston university

I had a look at Aston universitys video and there is really nothing new there. It is straightforward pyrolysis of organic material to produce syngas and pyrolysis oil.
The example of pyrolysis oil shown in the video was derived from rice husks which is a very good feedstock. General household waste will produce a much lower grade oil. If the waste contains any oil or fats the pyrolysis oil will be contaminated with propenal ( also called acrolein, look it up on Wikipedia) which makes it very toxic and difficult to use. General household waste will also contain water which will consume a lot of energy being boiled off.
Im not saying that their system wont work, it will, but as always in these situations they are ignoring the downsides in order not to scare off investors.

I also had a look at aston universities pyrolysis plant this one is a augur (inside reactor) type continuous feeding plant but after watching closely I observe that augur shaft has two rotars which are rotating in opposite directions how is that possible , what this mechanism is and what for please any one explain .

thanks in advance

[mjohnson1]

lowriderzzz

If the catalyst drops into the retort it will still be working actively to crack the hydrocarbon chains. There is either catalyst placed in the gas phase like imakebiodeisel does or the liquid phase like many others do including myself. The reason I prefer liquid phase is because it helps to evenly disperse heat through the plastic.

Purge gas is what drives the oxygen and regular air out of your retort. You can use nitrogen or co2. If you want to just run it as a batch reactor without a continuous feed then you can add in a few drops of water and seal it up and begin heating. All 3 methods work. I personally use CO2 right now since I had some laying around but will be switching to nitrogen when my tank runs out.

Yes electric coils will be able to maintain your reflux temperature. You'll need a PID controller and solid state relay though.

Yes for the liquid phase I put it straight into the retort. I usually put it on bottom and top of the plastic.

Right now i'm testing new catalysts and catalysts mixtures. I don't use much of a reflux column because I want to capture all fuel ranges.

[lowriderzzz]

lowriderzzz

If the catalyst drops into the retort it will still be working actively to crack the hydrocarbon chains. There is either catalyst placed in the gas phase like imakebiodeisel does or the liquid phase like many others do including myself. The reason I prefer liquid phase is because it helps to evenly disperse heat through the plastic.

Purge gas is what drives the oxygen and regular air out of your retort. You can use nitrogen or co2. If you want to just run it as a batch reactor without a continuous feed then you can add in a few drops of water and seal it up and begin heating. All 3 methods work. I personally use CO2 right now since I had some laying around but will be switching to nitrogen when my tank runs out.

Yes electric coils will be able to maintain your reflux temperature. You'll need a PID controller and solid state relay though.

Yes for the liquid phase I put it straight into the retort. I usually put it on bottom and top of the plastic.

Right now i'm testing new catalysts and catalysts mixtures. I don't use much of a reflux column because I want to capture all fuel ranges.

Oh I understand it better now.
I just don't get completely the purge gas thing. How do you pump it in the retort? Do you do it via compressor ?And especially with the additional feedstock intake mechanism.

What if there is no purge gas to push out the oxygen. Should not the oxygen naturally flow out when heat starts to raise up?

What if put few droplets of water in the continuous feeding chamber as well, so the vapor pushes away the in taken air ?

Finally what catalyst do you use for your liquid phase cracking ?

thanks again

[mtrans]

Cutting gas bottles can kill you if you are careless. Cut the top off carefully while still full of water.

I heard,not try,to put exhaust gas from car inside the bottle,only water isn`t enough as they say to me.
And don`t harry with exhaust,give it time.

[mercedes 308]

I had a look at Aston universitys video and there is really nothing new there. It is straightforward pyrolysis of organic material to produce syngas and pyrolysis oil.
The example of pyrolysis oil shown in the video was derived from rice husks which is a very good feedstock. General household waste will produce a much lower grade oil. If the waste contains any oil or fats the pyrolysis oil will be contaminated with propenal ( also called acrolein, look it up on Wikipedia) which makes it very toxic and difficult to use. General household waste will also contain water which will consume a lot of energy being boiled off.
Im not saying that their system wont work, it will, but as always in these situations they are ignoring the downsides in order not to scare off investors.

I think the second video is more interesting, from about 02.15 onwards.
If they succeed, could be a booming market for catalyst producers.

[imakebiodiesel]

I havnt seen a second video, post a link and ill have a look.
Mtrans, dont use exhaust from an engine. Exhaust contains a lot of oxygen, up to 35%. Propane requires just 40% to easily ignite. Water is the way to do it.

[mjohnson1]

lowriderzzz

The purge gas is put into the retort by going from a high pressure to a low pressure. You use a tank filled with nitrogen or co2 and hook a hose up to the gas inlet to your retort. If you want to use a rubber gas hose make sure you have an extension pipe coming off of your retort otherwise the rubber will melt.

The oxygen may flow out naturally but that isn't something you want to take a chance with.

Yes water would evacuate any air in any close container once it's heated to 100c or above and turned into steam.

Continuous feed is tricky and I would suggest you start out with a batch reactor.

I noticed in your picture that you don't have a way for the off gases to be vented. I could be wrong and it's just not visible in the picture. You need a way for the gases generated from your retort to be released. Otherwise you're going to have a big pipe bomb on your hands.

I don't wish to reveal the catalyst I use. It has taken me months of research and testing to get to where i'm at. I would suggest using some perlite or broken clay pots for your catalyst.

[ashiki]

hai everybody,
i am new to this place and have only been able readed a bunch of pages yet. i am in the process of making a plastic pyrolisis plant of 20ltr capcity,but i want the thing to be mobile and ultra light weight.what insulator to use? my design is almost like jetjis's ,just scaled down. i tried using glass wool sort of thing,but it just started smoking at 300°C. help me. it must be light weight

[Excalibur]

I heard,not try,to put exhaust gas from car inside the bottle,only water isn`t enough as they say to me.
And don`t harry with exhaust,give it time.

I've used the exhaust gas method for motor vehicle petrol tanks since the 70's.
It's good from the point of view that the tank can be immediately returned to service without having to dry the water out.

Even a few drops of water can make a problem with car petrol tank and fuel systems. Also a car fuel tank can't be water filled to capacity and at the same time be soldered or oxy welded.

Degassing and cutting LPG cylinders differ in that some residual water doesn't matter at all so I prefer the water & suds method for them.

My disclaimer is that I first used the exhaust gas method 40 years ago though I haven't used it on an LPG cylinder. Also I only use exhaust gases from a petrol engine.

[Excalibur]

hai everybody,
i am new to this place and have only been able readed a bunch of pages yet. i am in the process of making a plastic pyrolisis plant of 20ltr capcity,but i want the thing to be mobile and ultra light weight.what insulator to use? my design is almost like jetjis's ,just scaled down. i tried using glass wool sort of thing,but it just started smoking at 300°C. help me. it must be light weight

Kaowool is good to 1200'c or so.

[Excalibur]

Do you think the reflux column and condenser are too large for this unit ?
.

I think you should start with insulation on the reflux. As temps come up to target, then progressively remove the insulation. It may be on the large side but try it first.

What temperature should I maintain on both of them, if I want to make diesel that comes out at 380C (right ?) for the retort unit?
.

380 - 420'c for the retort, don't rush it. About 300'c for diesel at the reflux and tweak from there.

Do you think its a good idea to use blind pipes to put my thermometer probe in for the condenser and reflux column ?
.

Yes, I used 6mm blind tube and slipped in the tiny thermocouples. Worked well.

Any other critics and feedback will be greatly appreciated. Thank you.

I worry about the small pipe size.

Best to fit the reflux directly overhead of the retort with a single pipe. This will ensure the reflux can work correctly and so distillate doesn't pool in the bottom of the reflux.

Threaded pipe joins at retort/reflux will need a high temperature sealant. Thread tape etc will burn out and leak!.

[mercedes 308]

I havnt seen a second video, post a link and ill have a look.
Mtrans, dont use exhaust from an engine. Exhaust contains a lot of oxygen, up to 35%. Propane requires just 40% to easily ignite. Water is the way to do it.

There's three links in that post,