How to turn plastic waste into diesel fuel cheaply

[AAS]

Thank you Excalibur, AJ and BBD

Congratulations on great progress AJ!



A continuous set up allows for a smaller reactor. Instead of boiling say 100L in an 8 hour batch run you can drip 100L onto a hot plate at 1.67L per minute. Asad said he has his oil go from feed stock to vapour within a few minutes so in this example that represents just 5L in the retort at any one time. Surely this is safer than a 100L retort? Pfaulder reckons they get their feedstock evaporated within seconds.
Downstream the system is the same as a batch system so no safety differences there. Is it upstream that you are concerned about? Having a bulk tank feeding to a hot system? Or is it the possibility of air entering a continuous feed system? I'd like to address any potential issue before fabrication.
Col

Hi Col

Your argument is sound. I agree the size of the reactor can be allot smaller.

The next section is just my thoughts and not meant to offend anyone:

My philosophy is to keep things simple, less specialized parts mean less variables that may go wrong. If you want to commercialise the process the benefits of a continuous process in MY OPINION does out way the negatives.

However in a third world environment such as africa, robustness and simplicity goes a far way.

Obviously not saying I won't ever consider a continuous process, just think for any novice(myself included) please be very CAREFUL and rather build a batch setup first before considering a continuous process right of the bat.

Regards
AJ

[Beyond Biodiesel]

A continuous set up allows for a smaller reactor. Instead of boiling say 100L in an 8 hour batch run you can drip 100L onto a hot plate at 1.67L per minute. Asad said he has his oil go from feed stock to vapour within a few minutes so in this example that represents just 5L in the retort at any one time. Surely this is safer than a 100L retort? Pfaulder reckons they get their feedstock evaporated within seconds.
Downstream the system is the same as a batch system so no safety differences there. Is it upstream that you are concerned about? Having a bulk tank feeding to a hot system? Or is it the possibility of air entering a continuous feed system? I'd like to address any potential issue before fabrication.
Col

Precisley, this is why I have been focusing upon a 5 gallon (20L) system.

I'd bet there'd be some good set ups that could be engineered to make the flash evaporation concept work to good effect. Balanced matching of feed to heat applied might be something to look at. If my experiences of flash-boil-over events are anything to go by, then the carbon is going to come out with the product. I reason that if the feedstock oil is frothing in typical boil over fashion then a reflux will be completely ineffective.

The solution is to improve your reflux

Hi Col

Your argument is sound. I agree the size of the reactor can be allot smaller.

The next section is just my thoughts and not meant to offend anyone:

My philosophy is to keep things simple, less specialized parts mean less variables that may go wrong. If you want to commercialise the process the benefits of a continuous process in MY OPINION does out way the negatives.

However in a third world environment such as africa, robustness and simplicity goes a far way.

There is no reason why a continuous feed flash evaporator should be complicated or expensive to make. I have been reflecting upon the concept for about 2 years, and it is starting to look to me like the retort could be as small as a section of 2" pipe and a few plumbing fittings, which should be available at any hardware store. However, I would recommend avoiding galvanized pipe, and prefer stainless steel pipe and fittings, but black iron would do just fine.

[Col]

Hmm, yes I am beginning to see the value of building a smaller system first. Think I'll shelve the bigger one for the moment and test theories and ideas on a smaller scale first.
Col

[neophite]

Hi Jetis,

Thank you so much for what you've made available here! This will for sure help solve major problems. I am working to replicate what you've done and build a system now.

I've been looking through the threads and trying to find reference to a safety valve. Question is:

1- have you considered where is a good place to put a safety valve to minimise risk, and

2- on the blest machine there doesn't seem to be a bubbler, is there something else in system to clean the off-gas before cooling in to fuel?

Thanks

[Excalibur]

where is a good place to put a safety valve to minimise risk?

Because of reports of valves plugging with plastic, I think downstream of the reflux is suitable.

[ndsunil]

Precisley, this is why I have been focusing upon a 5 gallon (20L) system.

The solution is to improve your reflux

There is no reason why a continuous feed flash evaporator should be complicated or expensive to make. I have been reflecting upon the concept for about 2 years, and it is starting to look to me like the retort could be as small as a section of 2" pipe and a few plumbing fittings, which should be available at any hardware store. However, I would recommend avoiding galvanized pipe, and prefer stainless steel pipe and fittings, but black iron would do just fine.

What You say is absolutely right . One can think of 2" retort size for continuous pyrolysis . This depends on the capacity of pyrolysis per minute , heat input .
I have designed 5 M.T / 24 HOUR CAPACITY continuous plant . and my retort size of dia. 300 mm . I am going for direct dual gas/oil fired burner and avoiding hot air generator . The best way is going for microwave heating but the cost of system is very high .

[Col]

Chamber distortion

Ok, so I've drawn up a smaller system to get the ball rolling. Figured I'd use 150mm diameter pipe for each chamber. Also figured heating with hot plates and band heaters will keep it simple(r) and easier to control during the learning curve. So spoke to a manufacturer of band heaters to get some advise. Initially he was surprised I was going to be putting 425C heat into a pipe only 4mm thick and suggested the pipe could warp and distort. Also that when people are working with temperatures that high they are usually die casting into blocks of steel with very thick walls, he recommended I use pipes of 10-12mm wall thickness. I explained there will be a constant flow of oil vapours passing through the system absorbing and taking away the heat. He thought that might be ok. My question is - has anyone had any of their system distort due to high heat? If so please share the details such as type and thickness of steel, which part, temperature reached etc. If no one has then that information is also useful.
To those using mica band heaters, how hot can they go? Have you had to replace any? I understand mica is ok to 300-350C but if you want to go hotter than that you need to use ceramic band heaters, which will go up to 450C. I was just going to sit my retort and first condenser on hot plates and wrap my retort, reflux and first condenser in one large band heater each, all governed by temperature probes. Should be able to control temperatures in each chamber very well that way.
Thank you, Col.

[Col]

Temperature at shell v core of chamber

Has anyone put temp probes onto the wall and also into the middle of their retort or reflux? I'm interested to know if the temperatures are different and why (insulation, packing, direction of vapour flow...), and how large a diameter you can go before any difference becomes a problem.

[Beyond Biodiesel]

Ok, so I've drawn up a smaller system to get the ball rolling. Figured I'd use 150mm diameter pipe for each chamber. Also figured heating with hot plates and band heaters will keep it simple(r) and easier to control during the learning curve. So spoke to a manufacturer of band heaters to get some advise. Initially he was surprised I was going to be putting 425C heat into a pipe only 4mm thick and suggested the pipe could warp and distort. Also that when people are working with temperatures that high they are usually die casting into blocks of steel with very thick walls, he recommended I use pipes of 10-12mm wall thickness. I explained there will be a constant flow of oil vapours passing through the system absorbing and taking away the heat. He thought that might be ok. My question is - has anyone had any of their system distort due to high heat? If so please share the details such as type and thickness of steel, which part, temperature reached etc. If no one has then that information is also useful.

My retort is an aluminum pressure cooker that does not use an elastomeric sealing system. The wall thickness is about 1/8" (3mm). I am doing vacuum distillation, so my vessels and tubing regularly see a 1 atmosphere pressure differential, and I have taken my pyrolysis unit to 400c several times with no evidence of distortion. I used to have 1/4" (6mm) brass fittings and copper tubing on it, but they distorted. I have since changed all of the fittings and tubing on the retort to stainless steel.

At Chevron Research all of our cat cracking pilot plants used 1/4" to 3/8" (6mm-10mm) stainless steal tubing and compression fittings. The wall thickness of all of the retorts was about 1/8" (3mm). We even had pilot plants that were all standard Pyrex glassware, so I see no reason to use any wall thickness greater than 1/8" (3mm). Therefore non-galvanized, standard steel tapered fitting and nipples plumbing fittings should work just fine. Whereas, old oil drums and water heaters do not have sufficient wall thickness.

To those using mica band heaters, how hot can they go? Have you had to replace any? I understand mica is ok to 300-350C but if you want to go hotter than that you need to use ceramic band heaters, which will go up to 450C.

I have 2 mica band heaters on my retort. They are specified for 2400F (1300c) service. I have had no problem with them.

I was just going to sit my retort and first condenser on hot plates and wrap my retort, reflux and first condenser in one large band heater each, all governed by temperature probes. Should be able to control temperatures in each chamber very well that way.
Thank you, Col.

It depends upon your hot plate. Most hot plates designed for residential use will burn up at our retort temperatures. However, the thick electric coil that goes on a standard American-style electric range can easily go to 425C and more; however, the electric hookup to that electric coil was a bit of a challenge, I ended up using the copper clamping system commonly in use in high amp electric service panel applications with no problems.
[IMG][/IMG]
The hookup wire I used had to be special kiln wire, which appears to be stranded chrome plated copper wire, but it might be an exotic copper alloy of some kind. It was VERY pricey, but well worthy it.


You will also want ceramic bead (fish spine) for high temperature electrical insulation.

Has anyone put temp probes onto the wall and also into the middle of their retort or reflux? I'm interested to know if the temperatures are different and why (insulation, packing, direction of vapour flow...), and how large a diameter you can go before any difference becomes a problem.

I have placed all of the control probes directly underneath the heaters, so that the heater does not exceeded my control point. I have separate PID controllers controlling each heater. If you do not put the control probe on the heater then you will get hot spots. If you are using all steel fittings and retort, with 1/8" (3mm) thick walls, then you can take it up to 1200F (650c) if you want.

In addition to control probes, I also have several monitoring probes so that I can closely monitor boiling, reflux and condensation. So, I have TC probes throughout my system. One just 1" (2.5cm) from the bottom of my retort. One at the exit of the vapor stream, then one at the bottom of each condenser trap, and one at each of their exits.

[VAST]

LCD Display

Hi Excalibur

I`m trying to find lcd displays as you have for your temperatures but I just don`t seem to be able to find displays like that, can you give me a hint where to search for it?

I would like to have displays like that, that is easily readible from a distance.

The once I get it smaller and have two lines for the display.

I have ordered all the electronic parts, now I must just wait for it to arrive.

My flanges is being done, the moment I receive that I can start to build the machine.

[Excalibur]

From Ebay member procon_products
These work using non-grounded K type thermocouple. They read to 999*C. 12v. Often bought for EGT (exhaust gas temperature)

[neophite]

Because of reports of valves plugging with plastic, I think downstream of the reflux is suitable.

Thanks Excalibur!

[Col]

Chamber / parts distortion

Great, thanks BBD
Col

[Chris@NL]

Hello guys,

Its been a while since i wrote something on the forum.

Things have been crazy at work so i didnt have much time to work on the pyrolysis project.

But i have a question that can be interesting.

If i made about 500 liters of fuel a day, i would have to sell it on the black market because its not really legal to produce oil without all kinds of difficult laws and taxes. so producing on a big scale legally is impossible.

So for the last few days i have an idea in my head.

What if i use the exhaust gasses from a generator to heat the reactor and use the produced fuel to run the generator?

Legally i would be converting plastics into electricity?

Is this correct and do you think its possible technically?

i could make them believe its just an engine that runs on plastic

[Excalibur]

Hello guys,

Its been a while since i wrote something on the forum.

Things have been crazy at work so i didnt have much time to work on the pyrolysis project.

But i have a question that can be interesting.

If i made about 500 liters of fuel a day, i would have to sell it on the black market because its not really legal to produce oil without all kinds of difficult laws and taxes. so producing on a big scale legally is impossible.

So for the last few days i have an idea in my head.

What if i use the exhaust gasses from a generator to heat the reactor and use the produced fuel to run the generator?

Legally i would be converting plastics into electricity?

Is this correct and do you think its possible technically?

i could make them believe its just an engine that runs on plastic

The generators' motor will be making some good heat given that it will be under high load. Also the current produced could help heat, perhaps the infeed preheater. I suspect that the exhaust heat exchanger would need to be quite efficient to have the best chance of working effectively. Good thought, keep focusing on it.