How to turn plastic waste into diesel fuel cheaply

[wheels]

deleted double post

[fox32]

Filling the gap with dry, loose ash will work just fine for insulation. Coke is an even better insulator, but it will burn at 1200F (650c) unless O2 is not present.

Thank you for replies guys, i was thinking to do that, but i remembmered that there are some brickmakers in a forest near me, and they showed me an ancient romanian clay recepie that they use to insulate their brick burning ovens. It consists of 4 parts clay 1 part ash and 3 parts saw dust mixed together.
You can increse the saw dust if the brick dosn't have to suport itself or great weight. The saw dust will burn leaving tiny aer pockets in the material.
All the best!

[Beyond Biodiesel]

Thank you for replies guys, i was thinking to do that, but i remembmered that there are some brickmakers in a forest near me, and they showed me an ancient romanian clay recepie that they use to insulate their brick burning ovens. It consists of 4 parts clay 1 part ash and 3 parts saw dust mixed together.
You can increse the saw dust if the brick dosn't have to suport itself or great weight. The saw dust will burn leaving tiny aer pockets in the material.
All the best!

That is a good idea. I will have to try it.

On the immersion heater discussion above, I agree with wheels. Water heater immersion heaters have many problems, mostly they are not built for the temperatures required for pyrolysis of plastics, or distillation of WMO.

Even if one were to purchase an immersion heater capable of dealing with the environment of hydrocarbon pyrolysis it would still coke up right away. So I prefer a combination of a hot plate, band heaters, and line wrap.

[Excalibur]

I ran the Orion retort for the day and processed about 250 liters. There was a number of problems the worst of which was boil-over.

The balance scale for weighing the retort/reflux worked and I learnt quite a lot. Due to the growth of the retort, I eventually had to excavate underneath so it didn't sit on the ground and confound the balance scale reading.

Another initial pre-heater was trialed. It is a old water heater with a 240v immersion element. Temperatures up to 105°C were recorded at the heater vessel.

More thermocouple LCD temperature gauges were fitted all of which used non-grounded TC probes. Some exciting data obtained was the temperature of the exhaust pipe where it exits the retort. It recorded up to 250°C so I'm looking closely at harvesting that waste heat source for pre-heating ingoing feedstock.

Fiberglass insulation for the retort outer layer was added. Also the reflux was lagged with aluminum foil.

Most perplexing is the boil-over which spoilt a quantity of the diesel. It may need to be re-distilled. Some thoughts on the cause/s listed below:
1/. Too much water content in the (continuous fed) feedstock.
2/. Too much volatile fraction content in the (continuous fed) feedstock.
3/. A retort probe that is not immersed in the liquid isn't showing proper temperature, only recording that of the vapor.
4/. The extra insulation may be requiring a lot less added burner heat which confused earlier markers.
5/. Actual retort level might be higher than I think due to expansion said to be as high as 30% at 400°C.

Possible fixes include preheating the feedstock much more thoroughly allowing water and light fractions to boil off. Lengthen the retort probe to be in the liquid. Avoid the trap of trying to hurry the process.
Any thoughts on boil-over remedies?

(There's a new post on diydiesel about the run and some other pages are also updated.)

[Beyond Biodiesel]

It sounds like you are on top of the variables you need to solve, and a solution for each. Causing over-boil seemed to me to be the basic problem with a continuous feed system, so a low feed rate seems to me to be one possible solution in addition to all of the other solutions you have proposed.

[jonathan]

retort

great work excalibur.keep it up...do you feed oil from top or bottom of retort?

[Excalibur]

It sounds like you are on top of the variables you need to solve, and a solution for each. Causing over-boil seemed to me to be the basic problem with a continuous feed system, so a low feed rate seems to me to be one possible solution in addition to all of the other solutions you have proposed.

Agreed it's a fine balance. It's seems to be about knowing how much feed to have against how much addition heat to apply. Finding that sweet spot isn't so easy. I aim to process 400L a day so either I need continuous feed, batches in succession or a 500L retort.

great work excalibur.keep it up...do you feed oil from top or bottom of retort?

Thanks. Oil feed is from the top. For ultimate safety reasons I elected to not have any bottom or side pipe connections in the retort vessel. I was only just talking recently about internally piping the feed inside the retort to the bottom. So I was trying to understand whether it would be of any benefit. Perhaps isolating the feed inside a pipe would have less influence on the rising vapors. Another thought was there could be some additional preheating from the vapors heating the pipe however that would mean the vapors would lose heat so a mini reflux situation would occur. The heat has to come from somewhere. No free lunch as the saying goes...

[fox32]

NIcely done, that looks like a big scale though... I was thinking at a way to monitor the level of the retort, and was thinking at temperature probes put at 10 cm one from another and record the difference in temp, dunno how viable will be though. Great work! Maybe the boil over comes from the continous feed dripping oil onto the very hot reactor walls? Why do you think a bottom feed is more troublesome/danerous? i Was thinking of a pipe next to the reactor wall going to the bottom, this way the oil will catch some heat from the reactor wall.

[Excalibur]

fox32, I wondered about a series of TC probes for possible level monitoring as you have. I can't decide if it would work either. My retort is 1.5m deep, so it's a long length of TC pair which would need ceramic insulation.

I'll keep trying things till I find a solution to the boil over. It's just a bit frustrating.

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.

[jonathan]

retort feed

thanks excalibur......do you thing diesel from waste oil do any harm in modern engines? l meant very modern like 2010 to 2012....thanks

[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

[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.

[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.

[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]

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.