How to turn plastic waste into diesel fuel cheaply

[Excalibur]

Your fuel will be oxidizing and the formation of gum may be noticeable.
Butylated Hydroxytoluene is at least one antioxidant believed to work.
I'm not aware of any power loss however if gum restricts vehicle fuel flow then of course some power loss will result.
IIRC, petrol/gasoline is more likely to suffer from oxidization and gum. Good distillation practices are said to keep gum to a minimum. The fuel should be stored in cool environment (and it might be darkness was desirable to).

[rozier56]

rozier56

The diesel we are making from ldpe/hdpe plastics is light yellow in colour when produced.
The product darkens to a dark brown colour very quickly. I think this has to do with sucking up oxygen?. Are there ways to stop this,and will it reduce the diesel performance?

[sunilkm153]

: A very happy new year and happy experimenting to all energetic forum members

[Excalibur]

Wishing everyone best wishes for Christmas and New Year!

I've been encouraged to create a short tutorial video showing in simple steps, posting of photos onto a forum using Photobucket as host. I made this in the hope it would help those struggling with the process. If it helps, here it is:
How to post photos to a forum with Photobucket

[mindxploration]

Thanks guys. I figured 75 psi was bit much that's why I went with adjustable ones. Just set them for 10psi. Also I scored the pair of wika vacuum/pressure guages for 50 Usd shipped and were brand new. Ebay has some amazing scores on industrial parts if you search around.
My retort ran 500 shipped. Thought I'd mention a product I found at local auto parts store, blue magic brand extreme quik steel. Good to 1300c and strength improves with heat. States welds cracks and holes in iron and steel. Can be machined , drilled etc after curing.

[Excalibur]

As far as pressure sensors go, I thought a buzzer/alarm on pressure above say couple psi would be effective. Usually I'm too busy to notice a gauge needle. If pressure was as high as that I'd be wanting to investigate because it must equate to some kind of restriction.

[sunilkm153]

It's looking flash. I hope you haven't spent too much on it though. While the pressure sensors are nice, they are way over the top for what is really needed. But if they don't cost you much, then it is nice to have as much info of what is happening as possible.
The only thing that concerns me though, are the pressure reliefs settings 75PSI is a lot. Can you turn them down to a much lower setting. You only really need say 10PSI max. or even less. The Retort Vessel will have a significant reduction of it's pressure rating at the temperatures it will be operating at. 75PSI will be pushing it's limit somewhat. Plus Vapor escaping at 75PSI will be dangerous as it will jet a long way and will be at a high temperature. That makes it extremely dangerous to be around.

exactly 10 / 11 psi pressure is more then sufficient actually 300 mm water column ( 11 psi ) is the recommended pressure limit for commercial plants wheels is right it is extremely dangerous to release petrochemical vapour at 75 psi

[wheels]

There is only one valve in vapor stream just before bubbler. Other valves only close off condenser tanks from vapor stream. Also pressure guages double as vacuum guage and are safety features not requirements, although I think all safety parameters should be considered required. I have two 75 psi blow off valves with sintered flame arrestors, one on retort and second on first condenser tank. These are adjustable blow off valves set at 75 from factory.

It's looking flash. I hope you haven't spent too much on it though. While the pressure sensors are nice, they are way over the top for what is really needed. But if they don't cost you much, then it is nice to have as much info of what is happening as possible.
The only thing that concerns me though, are the pressure reliefs settings 75PSI is a lot. Can you turn them down to a much lower setting. You only really need say 10PSI max. or even less. The Retort Vessel will have a significant reduction of it's pressure rating at the temperatures it will be operating at. 75PSI will be pushing it's limit somewhat. Plus Vapor escaping at 75PSI will be dangerous as it will jet a long way and will be at a high temperature. That makes it extremely dangerous to be around.

[Excalibur]

There is only one valve in vapor stream just before bubbler. Other valves only close off condenser tanks from vapor stream. Also pressure guages double as vacuum guage and are safety features not requirements, although I think all safety parameters should be considered required. I have two 75 psi blow off valves with sintered flame arrestors, one on retort and second on first condenser tank. These are adjustable blow off valves set at 75 from factory.

Nice work! You've always gotta be thinking, what if.. what if, and have a plan.

[mindxploration]

There is only one valve in vapor stream just before bubbler. Other valves only close off condenser tanks from vapor stream. Also pressure guages double as vacuum guage and are safety features not requirements, although I think all safety parameters should be considered required. I have two 75 psi blow off valves with sintered flame arrestors, one on retort and second on first condenser tank. These are adjustable blow off valves set at 75 from factory.

[Excalibur]

Retort and reflux column together. Awaiting on couple fittings before water testing. Column is 6" round at base and ends up at 3" after adapters and filter plates. The 3 connections off tank around reflux column are pressure guage, temperature guage and 75 psi blow off valve with sintered fire arrestor. My pressure guage only goes to 15Psi , if I hit that I wanna be far far away before blow off valve goes.

The gauge should read no pressure throughout. Even the bubbler won't exert enough back pressure to register anything. If you have valving anywhere on the vapor stream, it should be locked in the open position. Use some sort of failsafe procedure so you can't accidentally startup with said valve closed.

[mindxploration]

Retort and reflux column together. Awaiting on couple fittings before water testing. Column is 6" round at base and ends up at 3" after adapters and filter plates. The 3 connections off tank around reflux column are pressure guage, temperature guage and 75 psi blow off valve with sintered fire arrestor. My pressure guage only goes to 15Psi , if I hit that I wanna be far far away before blow off valve goes.

[mindxploration]

One area that I had a hard time finding information to properly build was the retort pressure guage. In order to safely and properly read vacuum and pressure in these conditions several items are needed.
Pressure snubber - A pressure gauge snubber is a device used to suppress ("snub") excess force or rapid movement in mechanical systems. Pressure snubbers are designed to dampen the effect of pressure pulses and spikes to assure longer service life and readability of pressure gauges in harsh applications. For plastic pyrolysis a piston snubber with a D or E piston for light and heavy oil.
Diaphragm seal - diaphragm seal is a flexible membrane that seals and isolates an enclosure. The flexible nature of this seal allows pressure effects to cross the barrier but not the material being contained. Common uses for diaphragm seals are to protect pressure sensors from the fluid whose pressure is being measured. For my application I used 316l diaphragm and mineral oil for fill fluid between diaphragm and guage.
Finned cooling element - reduces process media temperature before reaching pressure guage

In order to use the diaphragm seal properly a seal fluid is used between diaphragm and guage that is non compressible. This allows for vacuum and pressure fluctuations to occur without damage to guage during spikes. This also separates the guage from directly measuring process media while protecting the guage. Mineral oil works well

[mindxploration]

Very much agreed. The fine tuning is in the reflux. Temperature control is key but so is sizing for flow rate and surface area of packing for proper reflux. That's one of the reasons I went with sanitary piping. Easy to add or subtract pipe length without a single weld. I'm not a welder so my whole refinery is off the shelf parts and available basically world wide through the Internet, mainly ebay. I'm using industrial parts for all aspects. Just waiting for the 33 gallon 83lb 316l pressure tank I'm using as a retort to arrive. Its certified to 90psi at 300f. Once I fine tune my system I will release parts list required to build.

[Excalibur]

More thoughts:
Good idea to test temperatures before insulating. It's likely that there'll be a good deal of radiant heat losses but step by step is the way to go. Getting the right balance of applied heat and insulation is something that each builder needs to experiment with to discover.
The ability to control both retort and reflux temperatures independently is important. From this perspective, adding/removing insulation layers in the same way we would put on or take off a sweater would be a good way to influence the reflux temperature target.
The retort just needs lots of insulation because if temps there climb too high, heat can simply be reduced.