How to turn plastic waste into diesel fuel cheaply

[Excalibur]

rozier56

You are right, it's not that simple. With the set up you describe, there is no control over what product comes out. Please re-read the forum and look for mention of "reflux" and study carefully. There are dozens of posts that go into the subject.

There is a video on the very first page of the thread by Jetijs and there are numerous other videos throughout the thread as well. Take your pick or see them all.
I suggest to read through the forum, a few pages every night. The info will be invaluable. There's a lot to know. Good luck.

[rozier56]

rozier56

Thank you,for your prompt reply.Guess this happens when you dont read all the details and want to jump the gun.I will check the video and read up more carefully.Regards.

[Beyond Biodiesel]

Thank you,for your prompt reply.Guess this happens when you dont read all the details and want to jump the gun.I will check the video and read up more carefully.Regards.

The thing that I try to impress upon everyone who takes an interest in pyrolysis is heating any large amount of hydrocarbons up to 800F (425C) is extremely dangerous. So, take all of the precautions you can, which starts with reading the entire thread several times.

[Excalibur]

This is really a journey of discovery. Initially even Jetijs, the one who originated this thread had problems with his fuel turning to wax. It was then he learnt about reflux adjustment. He refers to it as a "refluctor" in early posts. By the time your get to page 25 you'll know much of the basics but your learning won't stop there. This is a complex subject so enjoy the journey and please do contribute to the collective knowledge as and when you find something that works.

[cornishscrimper]

Hello everyone

What a read that was ! 88 pages of rollercoaster ride of info. I am going back to page one and read again taking detailed notes this time, as already any preconceptions I had have had of this process have changed. Thank you to all contributors who have made a wealth of 'closely guarded' information public.
I am looking to go off grid with my heating and then when that is mastered generating electrical power, in the UK you can sell back power to the grid under the combined heat and power scheme.

I have an engineering background and for 10 years ran injection moulding machines ! But now I design and research wood burning stoves for a big company (you can see a tie-in there I hope). I spend half my time working in Thailand and would like to transfer my knowledge (once acquired ) to help small co-operatives generate fuel and power - this is a long term goal of course but would help clean up the mountains of plastic I see polluting a lovely country- Sorry for this long post . I have started to gather bits already and look forward to the challenge with your help. Regards...

[Heartburn]

Thanks for reporting your findings. Over boiling is certainly an issue, but I did not know that it could cause cracked fuel to re-polymerize. Very interesting.

Hi Guys, it's been a while. Been extremely busy.

Very interesting in deed...

Just a note of caution about over boiling.

<snip> Hot waxy liquid began to spew out of the fuel outlet pipe. <snip>

I'm surprised that the uncracked product got that far. I expected the wax to condense in the reflux and not get out the end...

[vaseff]

I am wondering can we make the construction cheaper? Well, I was thinking about colours of the fire. As I know every colour is connected to specify temperature range. I wanted to exlude thermostat, thermocouples and so on... by using the gas burner (gas stove). The fire will be stable and I think it will ensure quicker and better results. We collect the diesel and petrol, but we can use the gas which is got out and minimize the process cost also.

[Mostafagaga]

its my first try to turn wast plastic to diesel , but after a few minutes its turning into waxes !!

so have any one solution for this problem !?!

[Excalibur]

its my first try to turn wast plastic to diesel , but after a few minutes its turning into waxes !!

so have any one solution for this problem !?!

Yes, this issue has been covered dozens of times in this forum. The answer is that your reflux is ineffective or non-existent. To run a retort using plastic feedstock without reflux will yield distilled wax! What's required is to "crack" the plastic, not merely distill it, hence the need for a reflux.
I'm just about to update my DIYDiesel blog with the reflux vessel details with pictures so it could give you some ideas on how to proceed. Else please search out the hundreds of posts on this thread for "reflux" (or "refluctor" as Jetijs called it early on). Hope this helps.

[Col]

Early trial, interesting result

Hi all.

Firstly, thank you all for your many constructive contributions to this bank of knowledge and experience. I have read and studied it all and found it very useful and motivating.

I find it interesting that some of us here (including myself) are so keen in the initial stage to prove this concept that we will quickly set up a crude system to get a quick batch test done without really considering possible (safety and other) complications of the process we are starting. About a year ago I wacked a heavy gauge 20L pot on top of a high pressure propane burner, put 3L of WMO in it, welded a couple of baffles into a riser, threaded on a 2" brass Y strainer with mesh removed so I could have a temp probe up in the branched vapour exit. Used copper pipe to direct the vapours to a 20L tank with 6m of 1/8th copper tube coiled inside, with a pump circulating water from a 10KL water tank through the cooling tank (I guess the water temp was about 19 degrees C). I didn't even know what a bubbler was, or purge gas, or what temperature to aim for.

All went well enough, no explosions, and I got some product out, initially water, then a mixture of water and light ends, then the stuff I was after. The product stunk like dirty, burned oil but was much thinner and had a lot of suspended particulate in it, it was very dark. I did not get 3 L of product out as I struggled to maintain a high enough temperature (I had no insulation at all). I turned the unit off at the end of the day part way through the batch. The next day I couldn't get the temperature very high at all, no condensate exited the system.

What I am guessing happened is that I never reached cracking temperatures and so instead distilled off the light fractions on the first day and was left with heavy oil in the pot. Is it the case that the distillation process itself will generate heat? Perhaps it is endothermic to a point then is (partially?) exothermic? If so then the combination of the propane flame and the exothermic reaction involving distillation of the lighter ends may have produced enough heat to maintain the process on day one but day two didn't have any light ends to distill therefor no exothermic heat so day two had less combined heat and couldn't reach a high enough temperature to cause the heavy oil to vapourise. It was over a year ago, no notes or photos, so I do not remember the temperatures reached.

Anyway, what might interest you guys is what I got from the condensate. There has been talk about the colour of the fuel being indicative of the type of fuel. But if you look at my photo you'll notice that the two samples are very different in colour, yet came from the same collection pot. Because the condensed fuel stunk and was dark I figured I'd soak it in some activated carbon and see if that cleaned it up. Soaking for 30 mins to a few hours didn't help. I left it over night and drained it through some filter paper to ensure I didn't get carbon fines in the clean sample. What I ended up with was the amber sample. It smelled better and looked great. (the thickness of the dark layer on the bottom of the jar is exaggerated in the image. It is a molasses-like substance, gum from oxidation I guess? Has only appeared gradually over the past year) After the weekend I wanted to dry out the activated carbon to use it for something else so I drained the remaining liquid out (through filter paper again) and ended up with the nice yellow product. I have had both of these samples air tight for over a year, only opening the jars a few times to test the odour of the fuel.

It would seem that either the activated carbon selectively soaked up the longer molecules, leaving just the lighter coloured fuel or cut longer chains into shorter ones, or somehow bleached the fuel. I threw out the original condensate when we relocated the business so only have the very small samples you see in the photo. I do not have sensitive enough scales to perform the BP test and determine what the fuel is comprised of using such a small sample. What are your thoughts? I do not believe the activated carbon was acid washed as I have used it with my fish tank at home and had no ill affect (though it is a big tank, and no I didn't use the same carbon as I put the oil through, didn't think the fish would appreciate it).

I will not be repeating the same system. My next set up will be different having read these many pages. Thank you for your input everyone.

Col

[Excalibur]

Hi Col. Good on you for giving it a go. It's from simple experimenting like this that much can be learnt.

If your WMO was a mixture of light and heavy oils, then the light oil will evaporate off first. Once that fraction has boiled off, then the required boiling temperature will rise to that of the next fraction present.
With regard to cracking oil, I read from the Shell petroleum book, when a light oil is cracked out of the feedstock, the remainder will be heavier. When still more light oil is cracked out, the remainder will go heavier again, and so on.

I just picked up a pair of high temperature sight glasses made from borosilicate 15mm thick x 100mm. I plan to install these at the entry to the diesel condenser vessel. To be able to see the flow/ drip rate is a very useful indicator of system health.

My two sight glasses


My idea of how I'll house the two glasses

[rozier56]

rozier56

Hi folks, busy reading through all the site,notice mention not to use copper in the process as it will act as catalyst. was planning to make condenser coil with copper coil if this is not suitable what metal shall i be using.Thks

[cornishscrimper]

internal pressure

I am re-reading the whole thing again , but is there a general agreement about how high the pressure inside gets up to? I think I read 1 bar somewhere, but have not found that bit again yet. I am thinking about relief valves.
I presume (a dangerous thing I know) that the back pressure will only be created by the bubbler. Otherwise it would just be naturally aspirated.

[Excalibur]

I am re-reading the whole thing again , but is there a general agreement about how high the pressure inside gets up to? I think I read 1 bar somewhere, but have not found that bit again yet. I am thinking about relief valves.
I presume (a dangerous thing I know) that the back pressure will only be created by the bubbler. Otherwise it would just be naturally aspirated.

You want no backpressure on the retort. Yes a bubbler will create a very small amount though this has the advantage that oxygen can't leak in.

Any notable pressure will raise the boiling point which then requires more heat.

Some folks are using relief valves but think positioning through carefully. Plastic can condense and plug the valve/piping making it ineffective. Boil-over from over eagerness to get the process moving or over filling the retort are likely causes.

[Ron Hammar]

Dlanor

Hi folks, busy reading through all the site,notice mention not to use copper in the process as it will act as catalyst. was planning to make condenser coil with copper coil if this is not suitable what metal shall i be using.Thks

What can be used is brake line it is steel and you can bend it into coils. Also you can have a good number of tube sizes.