How to turn plastic waste into diesel fuel cheaply

[Excalibur]

I read the tread but i didn't noticed exact design of the bubbler or I forgot it.

I made a simple sketch of how it looks like, can you just confirm if I'm right or wrong about the design of it.

Do you actually burn the gasses after the bubbler or you burn it only in case you don't use bubbler ?

Yes, it's not always easy to remember everything. It's why I read through the thread a 2nd time. I was surprised how much more made sense. Finding specific info in the thread is another problem though I have had some luck using "Advanced search", particularly when I know whose post I'm looking for as it's possible to specify a user name as well as a keyword.

Basically, the sketch looks OK. Ideal would be a transparent vessel or a window to see the bubbling. A means of filling, topping up and draining the water would be an advantage.

Good idea to burn the gases after the bubbler. This eliminates the smell and reduces the risk of simply having explosive gas floating around the site. The bubbler itself is an effective flame trap because flame can't jump from bubble to bubble.
One problem can be the stop-start-stop-start nature of the bubbles. This will tend to allow any flame to go out. A bubble diffusor might be the answer here. Also I would put a simple flame trap at the burner head. Some sort of igniter at the burner might be necessary on permanent ignition duty.

[operatorX225]

the gases should come from the condenser and enter the bubbler force itself through the water level and out to the exhaust stream. your arrow saying to condenser should be flipped over and say from condenser.

[lowriderzzz]

do I get the bubbler design right ?

I read the tread but i didn't noticed exact design of the bubbler or I forgot it.

I made a simple sketch of how it looks like, can you just confirm if I'm right or wrong about the design of it.

Do you actually burn the gasses after the bubbler or you burn it only in case you don't use bubbler ?

[lowriderzzz]

I made this for WMO,f110mm OD,heaters are 2x2kw in f70mm OD all IN ONE tube.
+ easy to heat
-not good for clean,easy vacuum put water inside,I DIDN`T get much,etc
I think boiler need some height to do our job.

so what if the boiler is still upright and there is internal heating on the top and the bottom is heated with classic way (fire).

Will this increase heat absorption efficiency ... by much worth ?

[mtrans]

Can you give suggestions please what is best to experiment with initially.

I made this for WMO,f110mm OD,heaters are 2x2kw in f70mm OD all IN ONE tube.
+ easy to heat
-not good for clean,easy vacuum put water inside,I DIDN`T get much,etc
I think boiler need some height to do our job.

[mjohnson1]

imakebiodiesel,

Thanks for your reply. You are indeed correct about the overcracking of the catalysts. I was very surprised when I was losing several grams of liquid fuel per hour just letting the container sit out in ~19C weather. I ran a second test last night and the conversion % increased by 7% and the fractions shifted towards the diesel range with still no waxes being produced. This was using the same batch of catalyst as the first test with no treatment to get the coke off.

Your kerosene could always be bleached with some type of bleaching agent if the color was a big concern.

90% conversion is excellent. Are you able to modify your catalyst to produce more off gases? Ideally, I feel that ~9% off gases will allow the unit to be powered on its own feedstock once an external heat source brings it up to temperature.

Your gasoline explanation is all correct. I should have referred to it as naptha like you said. I wouldn't trust this fuel in my modern car engine.

[imakebiodiesel]

mjohnson1, as you have probably worked out yourself you have a bad case of overcracking.
My guess is that you are using a very active catalyst such as zeolite or something similar. This produces a very high proportion of the more volatile fractions. It also has a very short working life before it cokes up which would explain the low total conversion ratio.
A smaller amount of your active catalyst mixed with a slower, clay type catalyst might just do the trick.

I am at present submitting a sample of my kerosene for testing to British Standards. I will know in a few weeks whether my fuel is up to the standard of commercial kerosene. Im fairly confident that it will pass on specific gravity, flash point, viscosity, smoke point and distillation test as can test for these myself. It may fail on colour as my fuel is not as pale as commercial kerosene.

In my latest batches in my new processor I am getting 90% conversion. The liquid output is 92% kerosene, 8% light naphtha.
The 10% residue is a black coloured paraffin wax. Both the light naphtha and the paraffin wax are saleable products used in various industrial processes.

Just a note on the use of the word gasoline or petrol to describe the light fractions derived from this process. Calling it gasoline will encourage beginners to put this fraction into the fuel tanks of their vehicles without further processing which will quickly do damage. Strictly speaking this fraction should be called naphtha. Naphtha needs to be upgraded, usually by hydrocracking to make it into gasoline. Naphtha itself is low grade, low octane fuel that has almost no lubrication or detergent qualities. From my own tests up to 25% naphtha can be added to high octane unleaded gasoline without risk of damage to the engine but no more.

[mjohnson1]

Can anyone else chime in on their overall conversion % by weight for liquid fuels?

[Beyond Biodiesel]

Hi guys! Today I cam up with another idea for how the heat absorption be made more efficient and I came up with the following design (on the picture below).


I saw on Blest bigger units the retort is actually laying horizontal so why not get heated both ends internally.

Soon my father is coming and we will build an experimental unit and I'll start sharing data.

Can you give suggestions please what is best to experiment with initially.

I will start with different types of plastic (PP and HDPE), the with temperature, then with catalyst and different combinations between those too.

Cheers: Ivo

Ivo,
1) there are good reasons to have the retort tall, as Excalibur pointed out avoiding over flow due to expansion.
2) The top 1/4 of the retort works well as a refluxing zone
3) Good luck finding an immersion heater that can handle 400c.
4) I use a hot plate on the bottom, plus band heaters on the sides, plus a heat top on the top and refluxing zone.

I finally got around to testing out a batch of my new catalyst and I wanted to post my results here-

Conversion rate:73% to liquid fuel (have no way to measure noncondensable gasses but significant "smoke" was coming out)

Fuel composition-
89.5% gasoline
8.9% kerosene
1.6% diesel

No waxes.

This is far from ideal as I want a conversion rate to fuel of ~90% with the remaining ~8-9% to be gasses to power the unit.

Impressive results.

Sure i'll not overflow it. Filling the half or perhaps 1/3 of it will be OK right ?

By the way how do you measure the progress of the process ? How do you exactly when do you shut the system, since there will lots of exhaust gases initially perhaps that will not be able to get weight measured in case i want to measure the amount of weight going out of the retort ???

Knowing when to turn off your pyrolysis unit is a big challenge. Monitoring the bubbler rate seams to be the best way.

I used to monitor the drip-rate into my kerosene and gasoline collection flasks, but I had trouble with sealing them, so they are now metal, so I cannot see into them. Excalibur view port idea hold merit here.

Early on I just monitored the temperature closely; and kept doing runs that went on all day, and finding the process complete, so I started backing off and found it took 2 hours for my pyrolysis unit to get to 400c, and 2 hours at the control point to complete the pyrolysis run. So, you might try the same thing.

[Excalibur]

Sure i'll not overflow it. Filling the half or perhaps 1/3 of it will be OK right ?

By the way how do you measure the progress of the process ? How do you exactly when do you shut the system, since there will lots of exhaust gases initially perhaps that will not be able to get weight measured in case i want to measure the amount of weight going out of the retort ???

I would say about 3/4 full is about right.

Thoughts on progress. The first thing you may notice is any included water will boil off as steam so it's a good idea to keep the temperature simmering around 100'c while it evaporates off. The bubbler activity is the thing to watch through the steam stage.

The rate of condensable fuels will slow toward the end. A higher relative quantity of non-condensable gas will then be produced. So somewhere around this time, the amount of return doesn't justify spending more energy to extract. This would be especially true if the heat was costing $$.

I'm building in a viewing port into my new refinery at the diesel condenser. The hope is that I can learn a lot from the drip rate and hopefully how the process is progressing.

Hope this helps.

BTW. On my blog I've just posted up 6 more detailed pics of my retort/reflux assembly. See the page titled: Turk-retort vessel mk6, item 4

[cornishscrimper]

Sure i'll not overflow it. Filling the half or perhaps 1/3 of it will be OK right ?

By the way how do you measure the progress of the process ? How do you exactly when do you shut the system, since there will lots of exhaust gases initially perhaps that will not be able to get weight measured in case i want to measure the amount of weight going out of the retort ???

I know the diagram is probably a 'schematic' rather than a plan, but just to test my own thinking - would not making the top large diameter feed tube longer help with the design? Just asking to see if I am getting the principles right. This a question for interest only.

[lowriderzzz]

Your design shows feedstock filled to the top hatch!! Jetijs warned of overfilling and showed graphic pictures !! Leave some gap at the top of the retort!!

Dual heat sources has some advantages. The electric elements can be thermostat controlled very easily and the flame can bring the retort up to temperature. Please be careful that you never get into a boil-over situation because that could lead to plugging of the pipework like Jetijs pics.
You need the patience of a Saint. Watch the bubbler and be aware of the amount of gas flow there is ...or isn't.

Sure i'll not overflow it. Filling the half or perhaps 1/3 of it will be OK right ?

By the way how do you measure the progress of the process ? How do you exactly when do you shut the system, since there will lots of exhaust gases initially perhaps that will not be able to get weight measured in case i want to measure the amount of weight going out of the retort ???

[mjohnson1]

I finally got around to testing out a batch of my new catalyst and I wanted to post my results here-

Conversion rate:73% to liquid fuel (have no way to measure noncondensable gasses but significant "smoke" was coming out)

Fuel composition-
89.5% gasoline
8.9% kerosene
1.6% diesel

No waxes.

This is far from ideal as I want a conversion rate to fuel of ~90% with the remaining ~8-9% to be gasses to power the unit.

[Excalibur]

Hi guys! Today I cam up with another idea for how the heat absorption be made more efficient

I saw on Blest bigger units the retort is actually laying horizontal so why not get heated both ends internally.

Your design shows feedstock filled to the top hatch!! Jetijs warned of overfilling and showed graphic pictures !! Leave some gap at the top of the retort!!

Dual heat sources has some advantages. The electric elements can be thermostat controlled very easily and the flame can bring the retort up to temperature. Please be careful that you never get into a boil-over situation because that could lead to plugging of the pipework like Jetijs pics.
You need the patience of a Saint. Watch the bubbler and be aware of the amount of gas flow there is ...or isn't.

[cornishscrimper]

no needto apologise

You are correct, there are so many people posting here, and a lot of it, is precisely what you described. So, I tend to err toward preaching safety. Sorry.

I think you guys are doing a marvellous job and there is no need to apologise to me. Safety needs to be number one job in this pursuit !