How to turn plastic waste into diesel fuel cheaply

[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.

[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.

[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?

[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.

[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.

[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.

[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.

[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.

[VAST]

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

[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.

[Excalibur]

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 crystalized.
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

[Excalibur]

We probably need to be clearer on what feed stock we are talking about. WMO or Plastic. Excalibur is using WMO of course. The temperature that initial vapors start to form is still a far cry from the temperatures needed to pyrolyse the heavier fractions. Diesel weight fractions are in the range starting at about 350degC for instance. However, it is also about getting rid of everything from the retort. WMO maybe slightly different, but most of us really want to be left with a dry'ish Carbon in the retort, rather than some baked Tar substance that would be impossible to remove.
The other issue that needs to be considered is water. If water is in the system, which it often is, it can have a major impact on temperature accuracies until it is all boiled off.
Normally FVT systems have a fairly constant energy input and the feed rate is varied to achieve and maintain total vaporization.

[wheels]

When it reaches its maximum heat at best results, then introduce new feed stock heated to 180 to 195 degrees( gas starts to form at about 200 degrees if I remember correctly) before entering the system,

We probably need to be clearer on what feed stock we are talking about. WMO or Plastic. Excalibur is using WMO of course. The temperature that initial vapors start to form is still a far cry from the temperatures needed to pyrolyse the heavier fractions. Diesel weight fractions are in the range starting at about 350degC for instance. However, it is also about getting rid of everything from the retort. WMO maybe slightly different, but most of us really want to be left with a dry'ish Carbon in the retort, rather than some baked Tar substance that would be impossible to remove.
The other issue that needs to be considered is water. If water is in the system, which it often is, it can have a major impact on temperature accuracies until it is all boiled off.
Normally FVT systems have a fairly constant energy input and the feed rate is varied to achieve and maintain total vaporization.

[Excalibur]

VAST

Yes, I have a prototype partly constructed to test the theory. I reason that a variable feed could be applied to a constant heat. In this way adjusting feed rate would control core retort temperature.
Currently I'm struggling to get an accurate, reliable means of controlling flow. Pre-straining/filtering the feedstock oil seems inevitable to stop plugging of any micro-adjustable needle valve.
One thought was to use a dosing pump but they aren't commonly available in the range I need. Another idea was to use a peristaltic pump typically used for chemical dosing but again they are not common in the range required. For the test purposes I'll probably elect to use a gear pump, pressure relief valve and micro-adjustable needle valve.

[VAST]

Excalibur

In an earlier post where we talked about flash evaporating the feedstock, I mentioned heat as a way to determine how much feedstock needs to be fed with a continues system. Have you looked at this possibility as a way to measure how much feedstock to feed into the system?

If you can find the optimum temperatures in which you have the biggest flow rate, can you not use that to regulate your stock feed input?

When it reaches its maximum heat at best results, then introduce new feed stock heated to 180 to 195 degrees( gas starts to form at about 200 degrees if I remember correctly) before entering the system, let the temperatures drop to a good constant flow rate where you still have good results and stop the feed until the higher temperatures with maximum flow rate is achieved, or find a constant temperature and flow rate that you are satisfied with, also maybe looking at keeping the feedstock in your retort lower than the actual maximum of your allow feedstock even at the cost of loosing the capacity of the retort. I believe that will increase the flow rate and capacity in which you can introduce the new feedstock and still achieve good flow rate.

Forget to use the maximum capacity of your system from a cold start, that is for a batch system, a continues process will work in the opposite direction where a smaller volume will give faster and better results.