How to turn plastic waste into diesel fuel cheaply

[MangiPNG]

Hi Guys,
Good to be back.. I see a lot has gone on since I've been away. Still reading through with great interest. Well I've stopped construction on my larger plant and decided to build a small lab scale one first so I can easily tweek and test different catalysts. Plus the explosion will be kept at a minimum. I've posted a pic of my work (still under construction) and encourage all your comments please.. Good and Bad!

[Excalibur]

Latest System!
This system has a 260lt retort with a 90lt re flux
We are using pp and pe as plastic raws.
Retort temps are 480- 510*c.
Reflux temp is 280-300*c.
Condenser is counter currently cooled.
Diesel collection chamber kept at 65-70*c.
Diesel collected varies between 0.79-0.82 on hydrometer.

Tried to increase reflux to 320*c and up to 350*c and started producing some wax content.Was trying to increase capacity but ran into wax situation.This also can cause blockages to inline filters and burner nozzles when wax particles are present in the burner fuel supply.

I have found that my production flow is reduced when the burner temps required at the reflux is reached and the burner switches off.The temp will increase by approx 10*c and then drop down approx 10*c below the set reflux temp{280*c} before the burner re-ignites.This is the time when production slows a lot.
Sounds like i need better burner control,or the ability to control the burner flame?What ideas are there out there?
Would also like to know were i can get info on the chain lengths for different plastics utilized ie; ldpe and hdpe,pp,pe,etc

It's great that you are trying new setups because you can learn what works best by comparison.
The hydrometer readings are overall a bit light. I suggest you raise the reflux temperature but do not increase the retort temperature to do so. There are several options to engineer this, some may or may not apply.
1/. Reduce reflux volume
2/. Insulate reflux.
3/. Move reflux closer to retort.
If your retort temperatures are not producing wax or suffering boil-over then it's difficult to argue the temperature level is not OK.
The diesel collection chamber temperature is satisfactory for those who want to maximize the amount of liters made with any reasonable stability. The diesel made like this though not absolutely perfect by industry standard will work well enough for DIY

Burners that have only one setting aren't ideal. Better would be some way of tailoring the flame heat to suit the retort requirement on the fly. One thought is to adapt a fuel pressure control adjustment. Another idea is to use multiple fuel nozzles, each with an individual valve or solenoid. Either of these ideas may require air adjustment compensation for ideal air/fuel ratio.
Currently Orion runs a injector pump with 4 fuel nozzles. There are 2 settings, power mode and idle mode, each has manual min/max adjustment screws. A solenoid responding to retort temperature switches between the 2 modes. My thought at a later more advanced stage is to re-introduce Arduino to control a servo on the fuel throttle based on retort temperature.

[wheels]

Wheels, I take my hat off to you. The explanation was impeccable.

Thank-you. It's nice to know I am communicating complicated info across OK.

[alejandroramallo]

Wheels, I take my hat off to you. The explanation was impeccable.

[piccolo chimico]

Very good explanation Whell

[wheels]

Latest System!
This system has a 260lt retort with a 90lt re flux
We are using pp and pe as plastic raws.
Retort temps are 480- 510*c.
Reflux temp is 280-300*c.
Condenser is counter currently cooled.
Diesel collection chamber kept at 65-70*c.
Diesel collected varies between 0.79-0.82 on hydrometer.

Tried to increase reflux to 320*c and up to 350*c and started producing some wax content.Was trying to increase capacity but ran into wax situation.This also can cause blockages to inline filters and burner nozzles when wax particles are present in the burner fuel supply.

I have found that my production flow is reduced when the burner temps required at the reflux is reached and the burner switches off.The temp will increase by approx 10*c and then drop down approx 10*c below the set reflux temp{280*c} before the burner re-ignites.This is the time when production slows a lot.
Sounds like i need better burner control,or the ability to control the burner flame?What ideas are there out there?
Would also like to know were i can get info on the chain lengths for different plastics utilized ie; ldpe and hdpe,pp,pe,etc

Many questions.
But firstly, the main answer is, you lack control.
Is the Retort fixed, or are you rotating or stirring the contents in some way? When you have a large Retort Vessel, the issues you run into is producing enough heat and getting that heat all the way through the Feedstock. There is a great importance in heating all the plastic as evenly as possible and maintaining an even heat distribution through the entire contents. Plastic is a very good heat insulator. If you use a Vacuum in the retort, the heat insulation is even greater. Using an inert gas does in some respects work to help heat getting through the contents better. But once the Plastic has melted and become one mass, then the insulator is back anyway. Why is this important? Well this answers your last question. The molecular weight of chains varies. Although PE initially produces a longer chain length than other plastics, once the plastic has been vaporized, the chains are in a continual state of change. They are breaking, but some join as well. The hotter you get the stock before the Vapor leaves the Retort, the more active the Chains and the more they break apart. So higher temperatures produce shorter chains. PE is also the culprit of producing Wax. But you can reduce or even eliminating that production with greater heat control. Either pyrolyzing the Stock above or below the Wax producing Temperatures. But the issue with being able to do this is getting the Target temperature all the way through the plastic as evenly as possible. If you can imagine, the internal temperature is going to be higher on the outer contact area of the Stock and it will be lower on the inside. Depending on the Plastic type, Vapor is released from ~350degC and on up. So lets say the Heat is 350deg at the centre area of the plastic mass, it may be 500degC on the outside. So you will get a different chain length being released throughout the plastic stock. This is one of the many reasons why commercial plants have so many varied plant designs with their Retorts. There is no one answer to all problems. Each design has a benefit and any negatives.
Reflux! It's way to big. Reflux is just about returning the really heavy chains back to the main source of heat, being the Retort, so they can be heated further and hopefully Broken. You don't need any large vessel to do this and it only makes it harder to heat. The lower temperature range of the Reflux needs to be the lowest temperature of the Chain length you require. So chains longer (thus heavier) than Diesel Fuel weights, will be returned to the Retort to be broken further.
Diesel weight chains start at about 150deg and range up to 260degC. So your main Distillation vessel is far too cold.
For the burner. I suggest you use Fuel that is not being immediately made. Make sure you use Fuel from a previous run and then filter it before burning it. But if you really have to use the fuel as it is produced, then the best way to stop it waxing in the line is to heat the line slightly. It does not need a lot of heat. Maybe even just insulation would suffice. Wax formation happens when the Fuel drops below 60degC or even lower.

Finally, and this is aimed at everyone in general. Stepping up the size of a Plant results in the issues and costs to rise exponentially. It is why fully understanding what happens internally, where, when and why is so important. It is why no large scale plant uses the same designs that back-yarders do. It is not just a case of heating plastic and then having it condense out onto a usable liquid. This is Chemical engineering. It requires a lot of knowledge, understanding and technical ability and all those abilities need to rise four fold with every step up in size. the Key is, keep the plants small and controllable. Once you step up to a plant than is going to produce more than a Vehicle tankful of fuel at a time(and maybe not even that), then you are entering a whole new realm in complexity. .
I hope that helps

[rozier56]

rozier56

Latest System!
This system has a 260lt retort with a 90lt re flux
We are using pp and pe as plastic raws.
Retort temps are 480- 510*c.
Reflux temp is 280-300*c.
Condenser is counter currently cooled.
Diesel collection chamber kept at 65-70*c.
Diesel collected varies between 0.79-0.82 on hydrometer.

Tried to increase reflux to 320*c and up to 350*c and started producing some wax content.Was trying to increase capacity but ran into wax situation.This also can cause blockages to inline filters and burner nozzles when wax particles are present in the burner fuel supply.

I have found that my production flow is reduced when the burner temps required at the reflux is reached and the burner switches off.The temp will increase by approx 10*c and then drop down approx 10*c below the set reflux temp{280*c} before the burner re-ignites.This is the time when production slows a lot.
Sounds like i need better burner control,or the ability to control the burner flame?What ideas are there out there?
Would also like to know were i can get info on the chain lengths for different plastics utilized ie; ldpe and hdpe,pp,pe,etc

[alejandroramallo]

With the time I will upload photos. Regards

[wheels]

Mr.Google translates it as:
Hello Alexander. Took time with this topic but I slowly and trying to learn from everyone and everything, now bought a grinding mill 10 HP and am making plastic collection in good condition and have two tons of shredded plastic packaging. Pending start another process more refined as yours. u7n greeting. I might add photos

Photos would be great. Thanks.

10Hp mill. That's a sizable investment.
2 Ton of Plastic. I hope he has done his homework. There is not much call for 2 ton of wax struck inside a steel vessel. As one or two have found out already.

[Excalibur]

Can anyone translate this to English

Mr.Google translates it as:
Hello Alexander. Took time with this topic but I slowly and trying to learn from everyone and everything, now bought a grinding mill 10 HP and am making plastic collection in good condition and have two tons of shredded plastic packaging. Pending start another process more refined as yours. u7n greeting. I might add photos

Photos would be great. Thanks.

[wheels]

Hola Alejandro. LLevo tiempo con este tema pero voy despacio e intentando aprender de todos y todo, actualmente compré un molino triturador de 10 HP y estoy haciendo acopio de plástico en buen estado y tengo dos toneladas de plastico triturado y envasado. En espera de comenzar con algún otro proceso más afinado como es el suyo. u7n saludo. podría añadir fotos?

Can anyone translate this to English for us all?
Then we may be able to help the Poster.

[ladanivaca]

Hola Alejandro. LLevo tiempo con este tema pero voy despacio e intentando aprender de todos y todo, actualmente compré un molino triturador de 10 HP y estoy haciendo acopio de plástico en buen estado y tengo dos toneladas de plastico triturado y envasado. En espera de comenzar con algún otro proceso más afinado como es el suyo. u7n saludo. podría añadir fotos?

[alejandroramallo]

Thank you very much for your advice Wheels !!!! I had thought to do it more or less in the way that you propose me. Means I'm on track

[wheels]

For those results, just need a digital weighing scale, a graduated cylinder, some test tubes, pipette. No more than that. I don't have a lab, it's a home experiment. Only I have small knowledge in chemistry. I think that, as the majority in this forum, we replace the elements that we lack, with ingenuity, and a lot of effort.

Arrr, now it all makes sense. What you have is what I was meaning by "Lab". It dose not have to be a proper laboratory. It's just that making a Fuel on a small scale like you have means you have far greater control and much easier to get a great result like you have. Your approach is very good. Learn as much as you can with this equipment. There is nothing better than being able to see what is going on as you experiment and learn. Then taking the next step to a larger scale version of Plant results in you being able to understand what is happening when the outcome is not so good. You know ruffly what kind of changes you need to do to make a better result. I believe that skipping this "Lab" style of learning and going straight to trying to make fuel with a large scale Plant is foolish and can even be dangerous.

[alejandroramallo]

Are you using a Lab set up? I had presumed you had a backyard u it. But the sample and the numbers you have expressed certain things with makes me wonder now if this is a small Lab type set up.

For those results, just need a digital weighing scale, a graduated cylinder, some test tubes, pipette. No more than that. I don't have a lab, it's a home experiment. Only I have small knowledge in chemistry. I think that, as the majority in this forum, we replace the elements that we lack, with ingenuity, and a lot of effort.