I'm following this thread with great interest. Regarding the auger idea. I have worked with these on cement screws I don't think that these are the answer. However the idea is great and I think that something out of the meat industry would be fantastic here. An industrial meat mincer has not only an auger to push the product but minces it as well. They are made out of stainless and they push through a nozzle. So very little reverse flow of gas that one would get with a feed auger. Also being stainless and very sturdy one could push the plastic into the bottom of the chamber on a continuous basis. These are available second hand in the food butchery business.
Thanks Sam, thats an interesting idea and one Im going to follow up on. A device that would shred, transport and extrude the plastic all in one operation would be very efficient. John Galts idea of hydraulically ramming unshredded film into an extruder is also a good option. This is what forums are all about, thanks guys.
Great stuff john, i will have to drop down to see in action soon, one question,
The catalyst, is it only fit to convert platics that have been evaporated?, or can we fill the retort with WMO (waste motor oil) along side the 15kgs of plastic also to fill in any pockets of air between the plastic & assist with purging of excess O2 in the retort?
"In times of universal deceit, telling the truth will become a revolutionary act" - George Orwell
The processor and catalyst will crack any form of long hydrocarbon molecule. To date I have successfully cracked, plastic. plastic/wmo, wmo, shredded rubber/wmo, veg oil, animal fat, animal fat/sawdust.
I chose plastic as the best feedstock because of the very high quality yield and low toxicity of the residue and off gas, but all of the others work.
Speaking of residue here are some pictures of the wax residue from 6 batches. I melted it at about 60C and mixed it with spent catalyst and an equal volume of sawdust. I poured it into a plastic dish and let it cool and set. I cut it into 4 blocks of about 1kg each and wrapped it in newspaper.
In an open fire or stove they light easily and burn steadily and cleanly for an hour.
When you crack other feed stocks ie rubber, glycerine (?) or wmo do you end up with different end products or does the catalyst and temp determine what the result is?
The fuels are very different.
Wmo produces a fairly clean mix of diesel and kerosene. but the residue is very toxic. With a lot of synthetic oil being used these days there are going to be chlorinated compounds in WMO which could produce dioxins.
Rubber produces a smelly dark red diesel type fuel, yield is low at about 60% and the residue is mostly black carbon.
Veg oil and animal fat produces a mixture of water and bio oil. The water separates and the bio oil floats to the top. Bio oil sounds nice but in fact it is the most horrible fuel you could imagine. It is totally black, about the same viscosity as diesel and has a truly awful smell. Your eyes begin to sting as soon as you open the cap of the bottle. It does not mix well with other fuels.
Are we talking chopped up tires ?
Yes Tyre recyclers shred the tyres and extract the steel.Its called crumb rubber and it can be bought very cheaply, about 60 euro a ton delivered. Its mostly used for paths, playgrounds and horse training tracks.
How many Litres of fuel could you expect to get from a ton of crumb ?
Ive only done a couple of small batches so Im no expert on cracking rubber. Yield seems to be about 50% by weight. Bear in mind that there will be 50% residue that you will have to dispose of.
Rubber is often co cracked with wmo. The wmo fills the air spaces between the crumbs, increasing the yield per batch and improving the penetration of heat throughout the feedstock. It does however mean the residue is much more toxic.
Crumb rubber or crumb rubber/wmo would be easy to feed continuously into a retort via an augur feed.
Crumb rubber is better used as a road material additive.
I have to agree with you, the yield is low and the residue is smelly and messy. Plastic makes a much better fuel and there is no residue that is difficult to dispose of.
Not only that Carbon Black is hell to deal with.It fly's in the wind, seeps into every crevice clothing included. Just not worth the effort except maybe on a large scale.
HI Jhon, I am new to this site. I am currently busy building a plant to make kerosene from waste plastic basicly the same as your plans. the only thing I do not know is what kind of catelist are you using? I am currently distilling wax and then distill it a second time to get kerosene!Please help. Andre812005
Sorry Andre but I cant discuss my catalyst as it is the result of 2 years research work.
Can you explain exactly what your catalyst does that would not occur without it?
Looking over this thread and your diagram of your device, I see nothing that would require a catalyst in cracking the plastic/ oil etc that could not be effected just with heat, albeit with some modifications to your processor in it's present form.
I have cracked plastic, Veg oil and WVO and it works perfectly well by heat alone. The key I found is that the vapors need to be superheated before being condensed which is where the real cracking occurs. Like you, I am not fractionally distilling the output, what I get is basically a diesel/ petrol blend. It will burn off it's own vapour like petrol but not completely. To effect that, one has to heat it as one would with Kero or diesel or pour it onto some balled up newspaper.
I am using it as an additive/ blending component to WVO so a petrol/ kero-diesel mis is of no consequence in my application.
I have run a few litres of straight product in one of my China diesels and saw no unusual buildup on the injector or in the exhaust port. I do think the mix was a little "Hot" on it's own with the petrol component but it did make the thing damned easy to start. If a person were using an engine in snow conditions, it may well be perfect as is. It suits me to cut it with a good amount of veg as it would be a big hassle to make enough to satisfy all my fuel needs although that said, with the rising price of petrol for my wifes car, I'm seriously thinking about a bigger processor and more a 2 stage fractionating column.
It's pretty obvious what you are using as a catalyst because there are only a few things that would work in this application and it's already used in industry anyway, but I'm curious as to what the benefits are in using it in a small scale setup like this?
From the description on the diagram of your processor, I'm guessing the main benefit is as a molecular Sive and to break down the long chain alkanes and aromatics at lower temps than would be required by heat alone. I'm also guessing that you are using it to increase overall yield.
The temps you specify seem to be a fair bit lower than what this stuff is normally run at which is also interesting.
The fact you are getting a gas you cannot condense is interesting to me as well.
I don't use a reflux column, I simply take the vapor from the superheater and bubble it through water to condense it. The fuel floats to the top and can be drawn off from there.
What I find an interesting difference between the output of your system and mine is that I get NO flammable vapours or smoke etc from the water condenser. I fully expected to from what I saw of other peoples systems on the net but try as I may, I just can't get anything other than the petrol fraction itself to light.
I'm wondering if the use of the catalyst breaks down the fractions so "fine" that the gas is a result of creating a tiny molecular structure that cant be recondensed?
Instead of using the standard catalyst, I set up a superheater section on my processor to take care of the waxes etc that form if the material, whatever it may be, is not cracked at a high enough temp. This seems to be were a lot of people doing this go wrong. As a result they get outputs which will will thicken and go waxy etc. My first batch did that and then after I added the superheater section, it just stays a liquid till at least zero oC which is as low as I have tested it so far.
I believe it may partially start to gell or solidify at some point below that but I have no need to worry about temps below zero.
One thing I like about my system is that is it stick and stone simple. I have no temp controls what soever. The only heat regulation is of the burner to regulate the boiling rate of the material being pyrolyzed. The superheater runs right through the burner flame and thus glows red hot. At first I ran the vapor output through an automotive transmission cooler with a fan blowing through it but the gas temp was so High I had problems with sealing the connections and melting gaskets etc. I did away with the condenser and just bubbled the output through a deeper water column and that works perfectly well.
Most systems using a fluid cracking catalyst of your type in industrial applications have to regenerate the catalyst to clear it of carbon and whatever other impurities may be present building up and blocking the pores of the substrate. Does your system require cleaning or replacement of the catalyst column or have you not so far processed enough material to need to do that?
You state the amount of residue you get is 5%. I have not specifically measured but I have a strong gut feeling my system would yield closer to 10 but it depends on what I cook. Most of the time I don't have enough plastic or WMO to fill the 50L Keg I use as a retort so I top off whatever I have with WVO. It all comes out the same in the wash as they say.
I imagine because I am probably using higher heat than you, I get no wax. The residue I get is just Carbon/soot and some often reddish clinker type material when I do a load of WVO. I don't know what that is and frankly I don't worry. I don't even bother cleaning the retort out after each run, I just load the next bunch of material in and go again. When I do clean it out, 90% or more of what is left comes out with a couple of bangs on the bottom of the keg with a mattock handle and a bit of a stir around knocks off the clinker that can stick to the bottom mainly.
If you used a granulator to shred the feedstock, you could then route some waste heat to an extruder section which would melt the plastic to a putty like consistency and feed it into the the retort without having to worry about air ingress. An auger of the right type should to the trick and could be a constant feed system or you could use a ram system which would be less constant but I doubt that matters.
The thing would be to basically pre melt the plastic so it was self sealing in effect as it fed into the retort. I imagine you would then compress the material to purge it of air by necking down the feed path as it got hotter and the plastic became softer and more liquid like.
Perhaps the hot section could use the waste heat from the burner flue to get enough temp for the premelt?
I look forward to watching your progress with your setup.
Hi Ttommy, Its sounds like you have your system well sorted. A catalyst is an additive that allows a reaction to take place at a lower energy level than normal, so yes simply more heat will do the same job. In my retort effective cracking happens at 385C, I would guess that your superheater is at least 200C higher than that, possibly more since steel begins to glow at around 800C.
The catalyst also helps to produce more fuel and a narrower range of fuels. My output is 80 % kerosene with 10% naphtha and 10% diesel and I am making progress in making it even more selective.
I dont use molecular sieves or synthetic zeolites like the oil industry, they are too expensive and can only be regenerated at very high temperatures. My catalyst is a mixture of common clays and minerals and is cheap enough to use once and dispose of.
If I want to I can continue cracking until there is only a few grams of carbon left in the retort but I find it is more energy efficient to stop early and collect a quantity of paraffin wax at the end. Paraffin wax has a high value in industry and with a little refining is worth more than the kerosene. Check out this link http://en.wikipedia.org/wiki/Phase-change_material
At the moment I am constructing a new processor which can run continuously. The plastic will be granulated and fed into the retort by an extruder as you described. This should be much more efficient and also has the potential to be scaled up to a much larger size.
Be careful of using naphtha as a replacement for gasoline, it has an octane rating of only 55 so will make an engine knock and overheat. It is however a great winter additive for biodiesel, preventing gelling and helping cold starts.
I want to read your post again and if I may will ask some questions. Thanks.
OK, I hadn't thought of that but it's a good way of refining the output.
I know where you are coming from. The zeos are expensive and hard to get outside of industry while the other is cheap and available everywhere. Thanks for clarifying the procedure with the catalyst. I thought it would have to be changed out if it wasn't re generated but I didn't see that specifically mentioned, only the retort itself.
Did you calculate the amount of catalyst needed or just work on the principal it's cheap enough to just use more than you need and change it out? Can you get it as a single product or do you mix a couple of the different ones with different base materials together. I know some use one material and some more expensive ( as it were) types use another but I haven't really analyzed them more than that.
This is probably more productive for output as well which would be an important consideration for what you are looking at. There is always a trade off between efficiency and maximum output for a given raw material.
I use one of my WVO burners for heating and as I'm not trying to do anything on a commercial scale or onsell as marketable product, efficiency has taken a backseat to simplicity with my processor. I put aside the crappy oil dregs etc that I get and heat them up and then just strain them through a shopping bag to get out the big stuff. Even though this oil usually has a lot of suspended water, it's fine for Burner use and saves my good oil and having to take the stuff back to collectors bins.
Fuel control has always been a problem with my burners and has been crude untill very recently using just a valve of the oil supply. Recently I came across a prebuilt timer board that allows me to pulse a pump.
By measuring the output of the pump, I can calculate the output in KW quite accurately and have the ability to leave a burner running without the need to stand over it in case the thing flares up or the lowering fuel level etc cause the thing to back off or die.
That's something I hadn't considered. I haven't gone into the science of what the product I'm getting is more than producing something that burns well and doesn't turn to wax at low temps.
No doubt the output varies somewhat between cooking plastic, Motor oil and Veg oil let alone varying amounts of all 3.
1kg of the catalyst will process 110 kg of plastic. the catalyst is granular and is suspended in a matrix of stainless steel wool, inside the reflux column. This ensures a good contact area and is easy to change between batches.
Can you post a sketch or picture of your processor as it is hard to visualize from your description?
I run a burner on warmed yellow grease to heat my house and found like you that a valve is not the way to control oil flow. I use an adjustable output peristaltic pump which has the added advantage that I can instal safety cutouts that will not let the pump overun.
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