How to turn plastic waste into diesel fuel cheaply

[rozier56]

rozier56

Do you guys think that a longer/taller reflux column with more packing filler will be beneficial?

[Excalibur]

Do you guys think that a longer/taller reflux column with more packing filler will be beneficial?

I prefer reflux columns that are tall and packed to increase the effective surface area. One aim is encourage greater intimate contact between rising vapor and falling condensate.

[mindxploration]

Hello everyone , new here and hoping for some feedback on my current setup. I haven't tapped for thermowell or reflux column yet, was thinking 2"x36" reflux on my 40l retort? Also I plan on purchasing a centrifuge but not sure how nice of one I will need for my planned uses. Hoping to use the diesel in my off grid motorhome heater and possibly fuel mercedes 300sd with om617 engine. Thanks for all the help you have all given already through this thread, I wouldn't be anywhere close to completion without.

[mindxploration]

Better view of individual condenser and tank setup. As well as safety bubbler and guage. I know guage is unnecessary as it shows vacuum and psi.

[Excalibur]

hoping for some feedback on my current setup.

Tidy work and a good start for a first attempt. The proposed reflux size seems like a good place to begin with. The key thing is that it matches the retort for size so it will operate within a usable temperature range. Be prepared to tweak the size or add/subtract insulation to achieve this.
The retort looks like aluminum, possibly a pressure cooker? Does it have a rubber seal? It will need a high temperature gasket or metal-to-metal seal. The pot itself in its' current form will lose too much temperature from heat radiation. It will likely require heat applied on the sides as well as the base. Any tapered pipe threads in the hot zone will be leaky. Tapered fittings or flanges are best. Good idea on the thermowell. Ideal is that it reads the actual liquid temperature. Another sensor in the reflux is essential.
Everyone's got to start somewhere. You are wise to start with a small experimental prototype. Good luck. I hope to read of progress as you test. Thanks for sharing.

[mindxploration]

Thanks for the help excalibur. It is an all american pressure cooker with metal to metal seal, already replaced the bakelite handles and will replace bakelite wingnuts with steel. Also have it slid in second aluminum drum and 2" ceramic insulation shoved in between the walls to hold heat. Using carbon steel plate in between burner and aluminum. Will be using exhaust cement on threads. Was planning on another temp guage on reflux as well as pressure guage but seems I need a chemical diaphragm seal etc to use pressure guage in extreme heat zone...
reflux will be packed with steel bearings, steel wool and ceramic Raschig rings. Thanks again for any input everyone.

While ordering the retort thermometer I figured 500c thermometer can handle 500c.... fail.
Received the tel tru thermo with clear warning stickers of 200f max case temp. Ordered appropriate thermowell for unit, whopping 4lbs. Should I still be concerned with radiant heat above retort being near 200f open air temp?

[Beyond Biodiesel]

Hello mindxploration, nice looking system that you have. I also use an All American Aluminum pressure cooker as a retort, with all bakelite pieces removed. I have had no trouble with it.m I also installed it inside an aluminum can with 4" of high temp insulation all around, and used high temp band heaters for heating it.

You will need PD controllers to control the heaters, and they come with thermocouple inputs. You will want to get high temp thermocouples to go with them. That will resolve your question.

The American Aluminum pressure cookers come with a pressure relief valve, which will have to be removed, and it is where you can install your immersion thermocouple. See photo of retort and its first condenser trap, which is also an American Aluminum pressure cooker. In fact my entire pyrolysis system is based upon several of these pressure cookers.

[mindxploration]

I'm trying to not go electric heating for my retort as I live off grid with far fewer panels then was it you beyond biodiesel? I remember someone here having 30 some panels. I live in my 34' motorhome and have 2kw solar but it's not optimally placed and it's fall now here in the PNW. I'm using a bayou classic stainless high pressure cooker. Already bought my thermowell and thermometer for the retort, 15 inch drops right down into the mix for reading true temp. Also trying not to use power for guages or water flow through condensers. I'm thinking of setting it up for the thermal siphoning to move water through a heat exchange of some sort. Also looking at an actual reflux column with Dephlegmator and Liebig Condenser. Thinking it could allow for 2nd distills of cleaner lighter fuels as well as emergency/overheat cool down. I tend to overthink and over build things ☺ what do you guys think of this column? Made with DHP copper Rod that melts at around 1,700° F not soldier which melts at 400f.

[Excalibur]

mindxploration
Press ahead with testing what you've got. Inevitably there'll be problems to solve. It will be interesting to see if the LPG burner will deliver enough heat and do it efficiently. Alum is a good conductor so maybe that will help.
I like the thermo-syphon idea.

One line of thought says the yellow metals (copper, brass, etc) are too re-active for a cracking/distilling hydrocarbons.

I think 200f will easily be exceeded above a retort that's at boiling temperature. Thermocouples are best for this type of work. You can't believe how hot 400°C temps really are. It's vicious on equipment, seals, etc.
Just take it step by step

[mindxploration]

I thought it would still be too hot, figured a small stainless bowl with a hole drilled in bottom and thermowell ran through and ceramic insulation stuffed around the case should protect it. And yes 400c is mighty hot and hard to wrap ones head around. How do you guys check pressure inside your retort?
Those using copper in reflux packing etc , how does it hold up?
I can get a stainless reflux if copper will not work.

Thank you thank you for the help guys, you rock!

[Excalibur]

You could run an old PC fan, blowing air into your bowl. They're 12v. Might work well enough.

The aim is to have no retort pressure though there'll be a very small amount created by any bubbler (and gas-jar if so fitted). I run a pressure gauge in the petrol/gasoline condenser where it's less than 20°C but it has never read anything above zero. It would only read if downstream was plugged. If upstream became plugged of course it would not read anyway. A gauge will only handle so much heat. I overheated one once to the point of being useless. Perhaps a remote gauge with a tube might be the go, however there has been reports of gauges/lines plugging from uncracked, solidified plastic.

I believe stainless or terracotta packing would be better than copper. I went to some effort to remove all copper and brass from vapor/condensate stream.

[mindxploration]

They have finned siphon snubbers that reduce heat by 75% it states, as well as protects from extreme pressure spikes etc. Then a diaphragm seal which is basically a bag of fluid that let's pressure changes occur while blocking the oil from contact with the guage itself. I'd feel safer knowing exactly when a block in the reflux happened if at all... fingers crossed knocking on plastic...
I was trying to go all stainless, or mostly stainless and zero electric. Would love to get a system dialed enough for fire heating using biomass. I live in the country, plastic and burn ables all over.
What were the effects on the copper or fuel production excalibur?

[Beyond Biodiesel]

I'm trying to not go electric heating for my retort as I live off grid with far fewer panels then was it you beyond biodiesel? I remember someone here having 30 some panels. I live in my 34' motorhome and have 2kw solar but it's not optimally placed and it's fall now here in the PNW.

Correct I was attempting to operate a pyrolysis unit that was powered by 30 133w solar panels. Yes, I was able to do it, but it was not without a great deal of effort. If I am to do it again, then I will have to have it plugged into the grid, or have a 6-10KW diesel generator delivering the power to run it.

I'm using a bayou classic stainless high pressure cooker.

As much as I understand your limitations, and value the cost reduction in burning gas or liquid fuel to fuel a pyrolysis unit; nonetheless, doing so is so dangerous, that you, and everyone else near you, would be better off if you went out and bought a gun and shot yourself; because pyrolysis of hydrocarbons is extremely dangerous and explosive. It should only be done by people who have been trained at graduate level chemistry to do so; but heating it with electricity is the only safe way that I can think of to do so. Heating a pyrolysis with a flame is shear suicide/murder.

Already bought my thermowell and thermometer for the retort, 15 inch drops right down into the mix for reading true temp. Also trying not to use power for guages or water flow through condensers. I'm thinking of setting it up for the thermal siphoning to move water through a heat exchange of some sort. Also looking at an actual reflux column with Dephlegmator and Liebig Condenser. Thinking it could allow for 2nd distills of cleaner lighter fuels as well as emergency/overheat cool down. I tend to overthink and over build things ☺ what do you guys think of this column? Made with DHP copper Rod that melts at around 1,700° F not soldier which melts at 400f.

Such a condenser will be just fine for the low temperature end of your system. I made one myself, and it worked just fine. However, it would corrode into a useless piece of oxidized copper at 400c.

My system fractionates on the fly producing the fractions that are common in a petroleum refinery. It is the most efficient way to do it.

[mindxploration]

Detailed refinery system

[Excalibur]

They have finned siphon snubbers that reduce heat by 75% it states, as well as protects from extreme pressure spikes etc. Then a diaphragm seal which is basically a bag of fluid that let's pressure changes occur while blocking the oil from contact with the guage itself. I'd feel safer knowing exactly when a block in the reflux happened if at all... fingers crossed knocking on plastic...
I was trying to go all stainless, or mostly stainless and zero electric. Would love to get a system dialed enough for fire heating using biomass. I live in the country, plastic and burn ables all over.
What were the effects on the copper or fuel production excalibur?

Placing a pressure gauge for safety purposes was something I gave quite some thought. Running a tube directly off the reflux to a gauge might work if the gauge was overhead and had free draining back to the reflux vessel. The unknown factor was how much uncracked plastic could be around. The reflux function is to separate uncracked heavy fraction from lighter weight so uncracked hydrocarbon could potentially solidify even in the gauge/apparatus itself. If you mount a gauge, periodically remove and test it, else test just prior to a batch run.

I say make all your pipework/fittings of a generous size and be mindfull of aspects of the plant that could even accidentally plug the vapor stream.

Talk about copper and brass was earlier on in the forum. I've just forgotten how it went. I think it was a chemical problem between hot hydrocarbon and copper.