How to turn plastic waste into diesel fuel cheaply

[Beyond Biodiesel]

I was thinking at a pipe connected to the reactor with a neodium magnet float.On the outside an iron ball. THe pipe would have to be from some nonmagnetic material, thus the magnetic field moving the ball up and down.

Now this section should also be isolated and the reactor may need more heat to compensate this section too.
And another problem, how do you atach, weld another material on the iron reactor.Any thoughts on this?
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The sight glass that you suggested here could work as a level indicator, because it would be out of the way of the fierce bubbling that occurs in the retort. It would have to be insulated, and allowed to be at elevated temperature, but below the 500F 260c) working temperature limit of a necessary high temperature elastomeric seal.

one way to implement it would be to weld two tapered thread fittings on the side of the retort, then a Pyrex tube could be sealed between two compression fittings, one on each end. The ferrules would have to be high temperature elastomerics, such as teflon or viton. An compression elbow at each end of the tube, would allow the sight glass to be attached to the retort. The sight glass would have to be held above the transition temperature of the hydrocarbon being pyrolyzed.

[fox32]

too bad there is no perfect solution for us backyard builders. I don't think the buble would work in an environment already full of bubbles. Didn't thought the float would explode...maybe made from pumice coated in molten aluminium.

About the magnets, if you are still into it, a Samarium - cobalt magnet should work, it is good up to 800c (curie point)


I was thinking earlier and another concept came to my mind, i see it workin there so bare with me.

A serated(with holes?) pipe the size of the retort, put inside the retort,and divided into 10 cm chambers all it's lenght. Every chamber should acomodate a metal ball that could float. Basically it would have one float in every section.
At the top of each section, 2 terminals positive and negative. When the level rises, it raise the ball until it touches the 2 terminals completing the circuit, and lights a led outside. And so on.
The wires would have to be all screwd in, no solder, and only ceramic coating. Some low intensity current so no sparks...

I can visualize it work, but some other thoughts are well appreciated. Some low intensity current so no sparks...

[wheels]

Hoddamdg11
I love the idea. Superbly simple. I thought that off-gases could be used for the task. They would need lightly pressurizing at just a few psi and fed through a regulator. The tube could possibly be piped to the bottom and the gauge would register whatever pressure equated to the particular level.
Yes, the bubbler would cause some distortion to the reading. My gasjar would give still more backpressure perhaps 1psi or so confounding the reading still further. Perhaps a small hose could be connected to the vapor stream and the pressure be applied to a diaphragm proportionally increasing the regulators spring pressure. This would work like a rising rate fuel pressure regulator in a fuel injector car. On the other hand, the extra pressure would need to be factored into equating it to a level so I'm not sure if you'd be any further ahead.

Re the float with magnet follower. I did some research a few weeks ago chasing magnets for this idea. If I recall correctly not all magnets like the temperature of 425°C.
The float might be affected by bubbles though there might be a point where the float was too heavy to be affected but still light enough to float on the liquid.
Then there is the Archimedes principle where a float can be below the surface but still have relative buoyancy. I found a number of tank level devices using this.

Some good ideas. I still see some little issues with each. Mainly with the expansion issue. The volume of oil will increase ruffly 30%, but it's weight does not and thus measurement of "head" pressure won't register a change. Also to gain accurate "Head" Pressure readings, you would need the tube to be as close to the bottom of the tank as possible and of course you have that 200mm odd of Carbon accumulating at the bottom.
A float would work, but it is going to need to be able to handle 400+deg and if hollow metal, not explode due to pressure increase from the heat.
Bubbling might work, but you are going to need a very sensitive gauge to measure with. And I a, not sure what exactly would happen if the Oil is in any form of Rolling boil.
The most simplest may simply be a short piece of Pyrex Glass Tube as a sight glass and encase it in a steel tube for protection, with a slot cut down the side so you can see a narrow section of the glass.
Or as you have often said, those Pyrex glass viewing ports you have.

[Excalibur]

Hoddamdg11
I love the idea. Superbly simple. I thought that off-gases could be used for the task. They would need lightly pressurizing at just a few psi and fed through a regulator. The tube could possibly be piped to the bottom and the gauge would register whatever pressure equated to the particular level.
Yes, the bubbler would cause some distortion to the reading. My gasjar would give still more backpressure perhaps 1psi or so confounding the reading still further. Perhaps a small hose could be connected to the vapor stream and the pressure be applied to a diaphragm proportionally increasing the regulators spring pressure. This would work like a rising rate fuel pressure regulator in a fuel injector car. On the other hand, the extra pressure would need to be factored into equating it to a level so I'm not sure if you'd be any further ahead.

Re the float with magnet follower. I did some research a few weeks ago chasing magnets for this idea. If I recall correctly not all magnets like the temperature of 425°C.
The float might be affected by bubbles though there might be a point where the float was too heavy to be affected but still light enough to float on the liquid.
Then there is the Archimedes principle where a float can be below the surface but still have relative buoyancy. I found a number of tank level devices using this.

[Hoddamdg11]

Level Notes 2

I’ve just remembered an extremely simple level measurement method – the bubbler. This normally consists of a tube sticking down into the vessel, supplied with compressed air by an air regulator. This is adjusted to produce a small stream of bubbles through the liquid, and as the level increases so does the back pressure thus indicating the level on a pressure gauge. For our purposes the compressed air could be replaced by our purge gas. Disadvantages would be that variations in our bubbler back pressure or existing purge would upset the reading, they would need to be fixed or compensated for, say by using a differential pressure device e.g. a U-tube manometer. Advantages are simplicity, robustness and relative cheapness.
It could also be used to show a point level by cutting off the tube at the required level and an increase in back pressure would show the level had been reached. It could also be used as a blockage detector to shut down the system.
A low level pressure switch could be recycled from an old washing machine as the high water level cutoff uses the back pressure caused by the rising water level compressing the air in a tube and operating a pressure switch to shut off the water solenoid.

[Col]

heat exchanger

Hi Kedigen
Wow, nice work. Do you intend to use the shell and tube heat exchanger in the retort or to pre-heat the feedstock or cool the distillate? If it is used in either of the first two options do you have any strategies for cleaning it out?
Col

[Hoddamdg11]

Level Notes

Some info on level measurement
As far as level measurement goes there are lots of options but the most common for vessels is to measure the head produced by the height of liquid in the vessel. It requires tappings at the top and bottom of the vessel and a trickle purge to both tappings to insulate the differential pressure measuring instrument from the vessel liquid. The purge flow, usually water, is set to the same value for both using rotameters and the effects should cancel each other out. That’s the theory. Kero or oil or some other liquid could be used instead of water.
The other ones I remember which could be suitable are Capacitive, Ultrasonic, and Radiation.
The capacitive ones measure the change in capacitance resulting from a level change. This uses a probe inserted in the top of the vessel. This would probably be the cheaper option.
The Ultrasonic ones bounce a high frequency pulse off the liquid.
The Radiation ones have a radioactive source which is attenuated by the liquid and picked up by a detector on the other side of the vessel.
All of these would be too sophisticated and expensive for a backyard operation.
If the idea is to control the level, some of them may be confused by the production of bubbles but then that may be good for preventing boilover by detecting the level of the bubbles.
Mechanical systems also have various disadvantages. The float and vertical rod has problems with the friction on the gland required for a seal. Another float idea is to use a magnet in a non magnetic vessel and a follower on the outside, which is not really suitable for a furnace. See magnets used to clean fish tanks. Here’s a thought - the follower could be in a sealed tube up the middle of the vessel, so it wouldn’t need a gland seal. The vertical rod mentioned by fox32 could be attached to the follower as the indicator but would need to be light weight.

[fox32]

Some points here:
1) It is common practice in the lab to drill out a compression fitting so that a TC can be run through it.
2) I know the 1/16" TCs work fine to 1200F (650c), because I spent a year at Chevron Research doing it, as did most of the other researchers there did.
3) A float is not going to work in a retort, because it will be a vigorously boiling caldron with a lot of foam on top.

Maybe a sturdy heavy float will go through the foam and settle on the liquid. while reading this i had an ideea dunno how viable would be.
I was thinking at a pipe connected to the reactor with a neodium magnet float.On the outside an iron ball. THe pipe would have to be from some nonmagnetic material, thus the magnetic field moving the ball up and down.

Now this section should also be isolated and the reactor may need more heat to compensate this section too.
And another problem, how do you atach, weld another material on the iron reactor.Any thoughts on this?


just an ideea.jpg

[Beyond Biodiesel]

Also about that compression fitting, couldn't we find one that alows a rod to move through it? Maybe graphite one... And we atach a empty steel ball (like toillet vessel)that floats in the reactor, to be moved up and down by the feedstock in the reactor? Of course the probe should witstand expansion from the heat and not jam at high temperatures.

Some points here:
1) It is common practice in the lab to drill out a compression fitting so that a TC can be run through it.
2) I know the 1/16" TCs work fine to 1200F (650c), because I spent a year at Chevron Research doing it, as did most of the other researchers there did.
3) A float is not going to work in a retort, because it will be a vigorously boiling caldron with a lot of foam on top.

[jonathan]

pyrolysis oil

thanks excalibur..l ask you because my friend put biodiesel in megane i dont remember the model and it doesnt work well (hard knocking) after a while the fuel filter blocked..after he replaced the filter and start again with same proplem then he put more diesel in car and it comes better....i dont know why

[Excalibur]

I've thought about the pipe feed running to the bottom of the retort a great deal but unless it's picking up heat that would otherwise be wasted, then I can't see any benefit. Unlike my proposed new set up where I'll make a pre-heat exchanger on the flue pipe and thereby use heat which would otherwise go up the flue stack and out to atmosphere. I monitored the flue pipe temperature and recorded up to 250°C of heat going to waste.

The compression fitting with float idea has some good things going for it. I came really close to making something like it. If I'd found a suitable float when I was hot on the idea, then I'd be testing it now. Perhaps a series in succession of neat fitting bushes with a drain between each so any gas escaping would drain off and be condensed in a nearby vessel.

[fox32]

The danger of bottom feed is the pipe goes straight through the flame zone. Should the pipe crack, raw hydrocarbon gases would be exposed directly to those flames. Once the heat began to increase, the fire would not stop till the fuel source was exhausted.

yes it is true if it is outside the reactor wall, i was thinking to put in the reactor straight to the bottom or maybe as a coil, it may produce some mini refluxing but i don't think it will be something severe.

Also about that compression fitting, couldn't we find one that alows a rod to move through it? Maybe graphite one... And we atach a empty steel ball (like toillet vessel)that floats in the reactor, to be moved up and down by the feedstock in the reactor? Of course the probe should witstand expansion from the heat and not jam at high temperatures.

[Excalibur]

Excalibur - re a long thermocouple to reach down into your reactor. Have you thought of using a Pyrotenax mineral insulated thermocouple in a stainless steel sheath. You can get them any length and in various diameters. They can exit through a special fitting or for the right diameter through a normal tube fitting such as Swagelock or Imperial etc. and have no trouble handling the temperature

Hey thanks. That looks like it would work out well. I searched and found TCdirect in Victoria. A 6mm probe at 1.5m is $57.90 so I emailed with a few questions. Inserting 1.3m into the vessel would seem adequate.

On eBay I bought extra long TCs that have a 1/16" (1.6mm) diameter, which I feed through a 1/16" (1.6mm) diameter Stainless Steel Swagelock compression fitting which has an 1/8" (3mm) NPT tapered fitting that is drilled and tapped into the lid of my retort. I have one that goes down to about 2cm from the bottom..

My first thought is a 1.6mm diameter probe might be too flimsy, free-hanging over the 1.3m drop?? I think I'll position a bit higher than 2cm from the bottom because I've had the carbon build up to 20cm.

jonathan. I see no reason why those modern diesels can't run on distilled diesel from wmo or plastic. This assumes that the whole process is carefully controlled and of a high standard.

[Beyond Biodiesel]

Excalibur - re a long thermocouple to reach down into your reactor. Have you thought of using a Pyrotenax mineral insulated thermocouple in a stainless steel sheath. You can get them any length and in various diameters. They can exit through a special fitting or for the right diameter through a normal tube fitting such as Swagelock or Imperial etc. and have no trouble handling the temperature

On eBay I bought extra long TCs that have a 1/16" (1.6mm) diameter, which I feed through a 1/16" (1.6mm) diameter Stainless Steel Swagelock compression fitting which has an 1/8" (3mm) NPT tapered fitting that is drilled and tapped into the lid of my retort. I have one that goes down to about 2cm from the bottom and one that is in the vapor stream exiting from the top. I also have TCs at various locations on the outside surface bottom, sides and top, to monitor my electric hot plate, band heaters, and line wrap.

[Hoddamdg11]

Long Thermocouple

Excalibur - re a long thermocouple to reach down into your reactor. Have you thought of using a Pyrotenax mineral insulated thermocouple in a stainless steel sheath. You can get them any length and in various diameters. They can exit through a special fitting or for the right diameter through a normal tube fitting such as Swagelock or Imperial etc. and have no trouble handling the temperature