How to turn plastic waste into diesel fuel cheaply

[VAST]

Thinking safety, I decided to post pics of my retort and failed flame ducting. The retort is OK apart from the scaly look which does come off with a wire brush. The flame ducting took a beating and collapsed, flooding the flame area with vermiculite. The steel duct looks very crystallized.
I'm considering cutting some .3 -.4m off the retort bottom not so much because the steel isn't good but because I think some greater distance between burner and retort would reduce the heat pounding. Possibly some kind of sacrificial brick or steel structure could take the brunt of the heat. In addition some sacrificial wear plates may be added to the retort.
The thought with this mod is to convert the flame zone into something more like an oven, instead of being like a blow torch.

Flakey retort mill scale. This steel flakes presumably from heat oxidizing the metal.


Ducting for flame from burner head. Pipe crumbled in flakes a bit like rust.
The ducting will be replaced with refractory bricks.
I'm pondering the options so please post with similar stories, pics or just a comment. HTH

Hi Excalibur

It is good to get pics of failures too. Nothing is really a failure as long as we learn from the experience. This is a good way to go to share with others, what works and what not, what to watch out for. How thick was the steel you used on the ducting?

I looked at your gas jar and decided that I will do something similar for the gas storage. Is it necessary to have the water tank open, won`t a water level work just as well to inform you where the gas level is in your storage tanks?

I was wondering this afternoon, how much water do you use in your heat exchange to cool down your gas? I`m installing the water inlets and outlets at the moment on the heat exchanger and thought about what type of reservoir I will need to cool the system down. Do you have heat gauges on your heat exchanger also?

I found this afternoon while welding the top flanges on the retort for where I will feed the raw material that it looks like the flanges warped a bit from the heat. It does not completely sit tight against each other.Most probably because I`m not really that good of a welder.

For my next project I will take all the parts to be welded by engineering works.

[VAST]

Some more photos of me working on the heat exchanger and its parts.

IMG_20141221_091343.jpg Heat Exchanger.jpg IMG_20141014_183148.jpg

[wheels]

Hi Excalibur



I was wondering this afternoon, how much water do you use in your heat exchange to cool down your gas?

I found this afternoon while welding the top flanges on the retort for where I will feed the raw material that it looks like the flanges warped a bit from the heat. It does not completely sit tight against each other.Most probably because I`m not really that good of a welder.

For my next project I will take all the parts to be welded by engineering works.

Re the water, as much as you can to get as much cooling as you can.

Even an expert welder will not stop warping. It's just a fact of Weld cooling and pulling. So the best is to bolt on as much as you can to keep the flange flat as you weld, then remove what you bolted on and then you need to lap the flange with grinding past till you have a perfect seal. Be prepared for several days of work lapping it in. It's a slow tedious process. Using blueing dye or similar to check the seating as you lap it in and don't stop till it is a perfect seal.

[mercedes 308]

Re the water, as much as you can to get as much cooling as you can.

Even an expert welder will not stop warping. It's just a fact of Weld cooling and pulling. So the best is to bolt on as much as you can to keep the flange flat as you weld, then remove what you bolted on and then you need to lap the flange with grinding past till you have a perfect seal. Be prepared for several days of work lapping it in. It's a slow tedious process. Using blueing dye or similar to check the seating as you lap it in and don't stop till it is a perfect seal.

Better to have tears from endless lapping. Than tears and a repair bill or worse if it blows up.

[Excalibur]

Hi Excalibur

It is good to get pics of failures too. Nothing is really a failure as long as we learn from the experience. This is a good way to go to share with others, what works and what not, what to watch out for. How thick was the steel you used on the ducting?

I looked at your gas jar and decided that I will do something similar for the gas storage. Is it necessary to have the water tank open, won`t a water level work just as well to inform you where the gas level is in your storage tanks?

I was wondering this afternoon, how much water do you use in your heat exchange to cool down your gas? I`m installing the water inlets and outlets at the moment on the heat exchanger and thought about what type of reservoir I will need to cool the system down. Do you have heat gauges on your heat exchanger also?

I found this afternoon while welding the top flanges on the retort for where I will feed the raw material that it looks like the flanges warped a bit from the heat. It does not completely sit tight against each other.Most probably because I`m not really that good of a welder.

For my next project I will take all the parts to be welded by engineering works.

Yes, agreed. I decided to put the pics up to help us all learn as a community.
Plus I reasoned that there is a responsibility to onlookers who may think, "making diesel is just too easy". If there really was a retort leak even by crack/pin hole, the feedstock would enter the flame zone already above its' auto-ignition temperature! One could expect to make the 6o'clock news

The ducting was 3mm at the most.

Re gasjar:
Yes, right, the upper vessel could be an enclosed vessel with a simple vent to atmosphere. Yes of course a water level indicator like a side hose would work perfectly well. I was going to use a cow drinking trough, concrete or plastic would have done. With an open vessel a simple float with a flag will do. I use a plain old 20L plastic "cubie" as the float.

Re heat exchanger/condenser.
I started using water in "counter-current". Then I swapped to feedstock oil as the coolant, again this is counter current. I don't aim to remove all heat because I want the diesel to be held at 60°C for the duration of the run. Currently there isn't a gauge on the diesel exiting the unit but there is on the diesel collection vessel which is immediately downstream. Also feedstock temperature is monitored where it exits the unit. A note though, oil doesn't work as well as water for exchanging heat onto so if the diesel flow increases, I'd expect to have to rethink. For now it's a handy method of lifting the feedstock temperature.

Sorry to hear about the flanges. For comparison my flanges were machined from 25mm plate. Because they use v-groove method for sealing, I lost about 5mm from the upper flange and maybe 3mm from the lower. I've done welding for a job and I say go bigger/heavier than you think you need on these. The pipe that the flange welds to will hold the shape of the sealing surface true so the diameter of 'seal contact' should be as close to the pipe diameter as reasonably possible. I spent the time to get the pipe dead true square so that when the flange was clamped to it for welding, there was no extra gap to fill. With any extra gap, there will be more pull and warpage from the weld.
BTW what type of seal are you using? Can it be fettled to work?

[Col]

I will be testing the use of 3 TC's in the retort, one above the reflux and one in the diesel tank.
I have welded a pipe to the base of the retort to make a thermowell for the first TC. The pipe will extend out through and past the insulation. This TC will monitor the temperature of the retort floor so I know what temperatures the oil is exposed to, and I should see a spike in this temperature when boil-dry is achieved.
The next two TC's are located in the belly of the retort, suspended from the ceiling. I have bent a return into the end of them so there will be no dripping of condensed vapours down past the end of the TC affecting the readings, they point upward. They are removable as they slide through a stainless steel compression fitting then are screwed into a bush and screwed into a socket large enough for the bend to fit through. I intend one to be located 150mm off the floor and the other 300mm off the floor. The retort is 600mm tall. I hope TC #2 and #3 will show slightly different temperatures as the oil level rises and falls, allowing the oil feed rate to be adjusted as necessary. I realise a 'rolling broth' in the retort could make registering temperature differences difficult. If so, then I will trial a cage / baffles of some kind around the TC in an attempt to keep the foam out and let the liquid in / out. Failing this, thermowells should work because the bubbles would transfer less heat and less efficiently than the liquid. Though it would be the same as if there were no cage or baffles or thermowell wouldn't it, just a delayed reading? Has anyone had success / failure with compression fittings on the retort?
Welding / warping - I welded 10" diameter x 22mm thick Table E off-the-shelf flanges between the retort and the reflux (reducing to 100mm pipe below and above the reflux - to allow space to reach my hand in for the packing), I will be using single-use spiral graphite gaskets for the seal. Haven't tested for any warping on the 10" flange yet. Was interesting to note that the supports I had cut and placed under the flange to sit it right before welding were completely compressed in afterwards. I had to cut them out. So there was more movement in the welding than I expected. Hopefully all is well.

[VAST]

I used stock flanges from my local irrigation store, the gaskets I let them be made for me from graphite according to the dimensions I provided for it.

On the reactor I have thick flanges as it will take the most heat, on the other vessels I went with a less thicker flange as I don`t think it is necessary for it to be so thick downstream.

The retort flanges is 15mm thick the rest 10mm.

[VAST]

Here is some pictures of all the probes installed, I was wondering what I should use to make a tight seal from gas leakage that can take the heat.

Maybe gasket sealer silicone? Or will the temps on the reactor melt that away?

IMG_20150101_070129.jpg IMG_20150101_070136.jpg IMG_20150101_070229.jpg IMG_20150101_070248.jpg IMG_20141231_191427.jpg IMG_20141231_191311.jpg

[VAST]

My Molds for the insulation from silicate jell and perlite mix, In will be poured in and stamped tightly between the inner liner and outer liner, set to dry and then released. Obviously the bricks will be removed and legs attached to the reactor that will support it and take the heat at the bottom. It will need to be strong enough to endure the heat from the burner.

IMG_20150101_092113.jpg IMG_20150101_093233.jpg IMG_20150101_101056.jpg IMG_20150101_101210.jpg IMG_20150101_122303.jpg IMG_20150101_122315.jpg

[VAST]

The water bubbler I`m going to use, from here the gas will go to the gas jar as in Excalibur`s Design.

Also some pics off the heat exchanger with the water inlet and outlet installed.

The grid for the reflux column that will support the metals shavings and the catalyst.

IMG_20150101_101312.jpg IMG_20150101_101322.jpg IMG_20150101_101835.jpg IMG_20150101_102158.jpg IMG_20150101_070224.jpg IMG_20150101_070229.jpg

[VAST]

The complete systems as to date without the mold and the water bubbler. I will install the water bubbler this afternoon and weld close the reflux after installing the grid. Maybe I will even include some photos with the mold covering the machine.

This system is small and easy to build with everyday material that anyone can get anywhere in the world, maybe only the see through water bubbler will be a problem, but the rest is easy to come by.

I don`t know how long the reactor will last as it is made from a 48kg gas cylinder, the walls is not really thick, between 2mm and 3mm thick, I won`t want to run this for a very long time. How long do you think a person can risk using such a thin reactor with it staying save?

The feeding tube that has warped from the heat, instead of sanding it I will just remove it and put on a new lid from a solid peace of steel I will cut with my plasma cutter. It was just the top lid that has warped as I welded on a peace of metal to close the hole in the flange to seal it. The ropes is there currently just as support until all the containers have there own legs welded on.

My Low tech plasma cutter jig for the hole cutting. Made from a piece of wire bend according to the length I need for the hole.


IMG_20150101_070030.jpg IMG_20150101_070144.jpg IMG_20150101_122512.jpg IMG_20150101_122528.jpg IMG_20150101_164415.jpg IMG_20150101_164435.jpg

[wheels]

Maybe gasket sealer silicone? Or will the temps on the reactor melt that away?

Yes the Silicon will melt. Exhaust Cement is better.
What's the rope around the pipe for? It will melt aslo.
The Steel casing around the Retort may need to be insulated as too much heat will escape outside. You want all that heat radiating into the Retort.
Also, paint the retort and the drum with an HT exhaust/Engine paint, or the paint they use on Pot Belly stoves. This will reduce the corrosion from the flame on the steel.
Keep an eye on all the Valves. They all have plastic seals and if they get too got, will leak.
It's really hard to get your head around the fact that the Liquid can be anywhere from 300 to maybe 500dgC. When something starts to fail, you can't just turn it all off with the flick of a switch. You end up standing there watching something melt not being able to do anything about it.
Not a biggy, but I think you have too many distillation vessels. I figure that most of the fractions are going to be cooled enough to condensate in the ver first container. I would look at insulating the first container to allow only heavy fractions to accumulate there and the lighter ones to move on to the next. Even insulating two container and the last water cool perhaps. That will separate even more weights of fuel.

[Excalibur]

VAST

Great work. Lots of effort!

A gasket will accommodate some flange irregularity as part of the job it does so it comes down to how out-of-true plus conditions of operation. We aren't running at any pressure to speak of so that helps.
Silicon sealants won't hack the 400°C+ of the reactor very well. I think I saw one brand that was resistant to 370°C but stated "intermittently".
I have some exhaust sealant containing sodium silicate but then I read it is was only rated to 300°C. I ended up not testing it either because I modified all my taper-threaded bungs to flange-washer-seal types. You can't believe how hot a 400°C retort really is. The heat is vicious. Teflon thread tape/ sealer is another one that doesn't work even on the slightly cooler reflux.

How long the 48kg vessel will last is the big question. 3mm wall is on the thin side especially for flame heated reactors. Prolonged overheating of steel will decay the metal. Recently I gathered up with a large magnet, the flakes of mill scale from my failed flame duct and also from the reactor. They weighed at nearly a kilo, yes nearly a kilo of flakes that look like rust without the red color.
OK, so what can you do? On the assumption that your heat source is a burner, I'd say fit one (or more) TC to monitor how much flame heat is being applied. In addition fully understand how to adjust the heat of the burner to suit requirement.

The reflux looks OK. Be prepared to lag it if it doesn't come up to temperature. In fact I think I'd lag it first, then remove lagging progressively if temperature target is exceeded. Realize though that the flange above it and the first right-angle pipe will add to reflux capacity.

[VAST]

Yes the Silicon will melt. Exhaust Cement is better.
What's the rope around the pipe for? It will melt aslo.
The Steel casing around the Retort may need to be insulated as too much heat will escape outside. You want all that heat radiating into the Retort.
Also, paint the retort and the drum with an HT exhaust/Engine paint, or the paint they use on Pot Belly stoves. This will reduce the corrosion from the flame on the steel.
Keep an eye on all the Valves. They all have plastic seals and if they get too got, will leak.
It's really hard to get your head around the fact that the Liquid can be anywhere from 300 to maybe 500dgC. When something starts to fail, you can't just turn it all off with the flick of a switch. You end up standing there watching something melt not being able to do anything about it.
Not a biggy, but I think you have too many distillation vessels. I figure that most of the fractions are going to be cooled enough to condensate in the ver first container. I would look at insulating the first container to allow only heavy fractions to accumulate there and the lighter ones to move on to the next. Even insulating two container and the last water cool perhaps. That will separate even more weights of fuel.

Just for your information as to the insulation. Silica Gel and perlite mixture = insulation.

Correction, my mistake. I`m talking about silicate gel while it is actually sodium silicate or "water glass".
https://www.youtube.com/watch?v=vQN7EqGMTuo

Another video about how to make your own silicate sodium.
https://www.youtube.com/watch?v=-Mx1-o1_MWo

[Excalibur]

https://www.youtube.com/watch?v=vQN7EqGMTuo

Good find on the DIY refractory making. I'm thinking of using the technique to convert some of my vermiculite to castable parts for the more difficult areas of my refractory. In my rebuild I'm dry stacking kiln bricks but the adapting of bricks to accommodate inlet and exhaust was proving a puzzle.