How to turn plastic waste into diesel fuel cheaply

[sunilkm153]

thanks for reply Excalibur

I'll call the burner service. I'll make a setting for the minimum temperature. I think I told glasscup the wrong place. it is among the diesel tank with heat exchanger. (picture 2). just to see the steam. there is very difficult to flow back into the reactor. but at the reactor outlet pipe, will I protract upwards? I need to extend matter how many meters? we work between 400-430C.this high?maybe also because we heat quickly?
I use my thermocouple 2m long. The reactor 3:30 meter. temperature measurement is accurate.
in this case the solution:
1) Is the temperature of 300-350 would be better?

2). pipe in the reactor outlet, is we do as in the picture? Did this work as reflux? (picture 1)

3) How many meters is necessary to extend?

you had a good fabrication layout but I think most important thing about positioning of catalyst tower and condenser unit which I think is wrong try to elevate these both above the height of reactor surely you will see the difference

[wheels]

Excalibur - on your blog you show a photo of the sight glasses with moisture on them. You mention you thought it was due to water in the feedstock. If you are targeting 60C in your diesel catchment tank are you confident there is no water in your resulting diesel fuel? I would have thought targeting 110-120C in this condenser would send all the water downstream to the next condenser resulting in good, dry diesel fuel. You would lose anything with a boiling point lower than or around 100C, and I think you are trying to keep some of that are you? to offset a relatively higher retort / reflux temp, allowing more heavier molecules through. More light and more heavy chains combining to your desired viscosity?

The "condensation" may or may not be water. The Hydrocarbons will condensate exactly the same.
If there is water, it will not be pure water as such. Remember that the Vapors have a lot of chemicals that upon contact with water, will become strong Acids. These Acids will instantly have a much higher Boiling point than pure water does.
And lastly, just because water is heated to beyond boiling point, it does not always mean it will turn to steam and carry on through the chambers. It may get trapped in the first chamber, even though it is super heated and it is possible that if saturated enough, it will condense out to look like water droplets. But due to no Air, it has nothing to be absorbed into, so remains in a visual presence. If you could expose it to atmosphere, I would expect it would almost instantly vaporize again.

[wheels]

Here is some photo`s about my machine, still not finished. But almost ready for the first run.

All feedback welcome.

Just for an initial comment, I would say your pipe work is too large a diameter. However, that is going to be trial and error.
My only one concern is that if you do not produce enough vapor flowing through the pi[e work, the chance of oxygen creeping back up the pipe work is high. That in turn could lead to a detonation. Although i don't think you have a vessel large enough to worry about any kind of dangerous explosion. It might go woof, but no dangerous bang and rupture of a vessel. By reducing the pipe diameter, you will speed up the velocity of the vapors transiting the pipe work and less chance of backfeeding.

[wheels]

One more thing.
Should Kedigen heat his catalyst chamber? And keep it at what temperature?
Any suggestions?

Yes!

Kedigan, the thing you have to understand is that each and every area will have an affect on what you get as an output. Hence why I originally said that I think you have jumped far to far ahead of yourself with such a large plant. You need lots of trials till you understand what impact each point is having on the output. So for instance,
Retort temp! This is a complex one because so much is happening in one area. First is the feedstock. Just because you have PP or PE, is not the entire story. You can have varying qualities of those. For instance, these plastics are fill of Dye for colour and plastsizers and maybe flame retardants etc. You can even have different molecular grades of the same plastics.
For a large scale production like yours, what is happening in the Retort is not so much an issue in my view. You want to vaporize the plastics as quickly and efficiently as possible. 460degC is about the right temperature for the most efficient vaporisation, but that can lead to other issues, which is what I think you may be seeing.
Reflux! As already has been said, there is no real reflux. That may not be so much a problem. It will affect what you get as a vapor stream and thus the liquid you condense. There are two processes to crack Hydrocarbons. One is the use of heat/time and the other is to use a Catalyst. A reflux uses Heat and Time. The very heavy "tars" etc are condensed and allow to fall back into the Reactor to be reheated, hopefully cracked smaller and then exhausted through the pipe work again. So you need a much higher pipe to allow that to happen. HOWEVER!
I will come back to the however part further down.
The second method of cracking is using a Catalyst. But nothing in Chemistry comes free. To make something work, you need energy. Energy can be the result of a reaction, called Exothermic. Two or more Chemicals react and one of the results of all the reaction is Heat. Or....you can make something react by adding heat as energy and forcing a reaction. In our case, that is how a Catalyst works. The Catalyst needs to be heated to an operating temperature so as the process takes place. The exact temperature is critical and you need to do lots of trials with that to see which is best for your situation. Volume of vapor, Temperature of vapor, type of Hydrocarbons, type of Catalyst material, how the vapor travels over a catalyst bed, will all have an affect on the output from that point.
So back to the However!!
When you get to a large scale plants, of which you have entered the world of, certain practicalities change how you carry out the process. As in, do you try producing the type of Hydrocarbon chains at the Retort end, like most all of the small scale guys here do, or do you simply vaporize it all quickly and efficiently as a large scale operation would want to and take care of the fuel in a distillation process, where you have greater control of exactly what you want as a Fuel.
Which is kind of the area you have entered into. You are very much in the area of needing a complex highly controlled distillation process. That means multiples of
Vessels, each very carefully controlled by temperature, some maybe even using separate catalyst chambers heated to specific temps etc etc. You simply will not achieve that with two containment vessels, because the result is getting only two ranges of liquids. The best way to tackle the stuff that makes the Fuel Solid, is to identify what it is and either remove it, or crack it into something else.
Your plant is kind of sitting across two worlds and not really working well in either. As I have said several times, every single part of the operation has a bearing on what comes out. Changing one thing will change everything else down stream, because you effectively change Time/Temperature and interaction of the various Chains and thus you change the output.
Sorry for the very long post.

[VAST]

Yes, the pipes is rather large for the "first test", but I am planning on upgrading it to a bigger unit, hence the big pipes.

This is just a test run for a few stages, my aim is to go for between 5000 liter and 10000 liter per day on a continues feed system.

This is just to test the waters until I reach a 1000 liters per day on a batch system. All the vessels will be swapped out and changed. A continues feed system reactor vessel can be far smaller than a batch system.

To achieve 10000 liter per day the flow rate will have to be at about 7 liters per minute, but I am still a far way from that, I can of course just buy a commercial unit, but why spend so much money just to avoid a learning curve?

[mercedes 308]

Just for an initial comment, I would say your pipe work is too large a diameter. However, that is going to be trial and error.
My only one concern is that if you do not produce enough vapor flowing through the pi[e work, the chance of oxygen creeping back up the pipe work is high. That in turn could lead to a detonation. Although i don't think you have a vessel large enough to worry about any kind of dangerous explosion. It might go woof, but no dangerous bang and rupture of a vessel. By reducing the pipe diameter, you will speed up the velocity of the vapors transiting the pipe work and less chance of backfeeding.

By reducing the diameter of the pipe, and speeding gas transit through it. You increase the possibility of uncracked fractions making it to the fuel storage tank.
Back feeding can be controlled by a one way valve, or bubbler design.

[VAST]

By reducing the diameter of the pipe, and speeding gas transit through it. You increase the possibility of uncracked fractions making it to the fuel storage tank.
Back feeding can be controlled by a one way valve, or bubbler design.

The bubbler is the last stage and will be a see through container, currently installing the electronic probes in all the right places, my third container vessel was added yesterday. After the electronics is installed I will start constructing a mold for the insulation which will be made from perlite and silicate gel, enclosing the whole reactor with a quick release lid that will help with cooling down the reactor once the process is complete by opening the top lid up to air.

I`m also thinking of catching the gas inside a inflatable container,don`t know if it will be suitable for gas storage, will still have to research it if I can find something suitable.

[mercedes 308]

The bubbler is the last stage and will be a see through container, currently installing the electronic probes in all the right places, my third container vessel was added yesterday. After the electronics is installed I will start constructing a mold for the insulation which will be made from vermiculite and silicate gel, enclosing the whole reactor with a quick release lid that will help with cooling down the reactor once the process is complete by opening the top lid up to air.

I`m also thinking of catching the gas inside a inflatable container,don`t know if it will be suitable for gas storage, will still have to research it if I can find something suitable.

Google gasometer.
Gas enters from base, rises through the liquid. And can be taken from top of floating compartment.

[wheels]

To achieve 10000 liter per day the flow rate will have to be at about 7 liters per minute, but I am still a far way from that, I can of course just buy a commercial unit, but why spend so much money just to avoid a learning curve?

Glad you realize you have a learning curve.
But you really need to keep all the plant at the same ratio's as you increase. Even then, there will be differences in output makeup. As merc308 states, the speed of the gas through the pipes will have bearing on the cracking.
Really, trying to save money on just one very small aspect like the pipe size suggests that stepping up to a three figure output/day is going to be too big a leap for you yet. As you will have likely read another member here has found it not so easy.
For any of you looking at large scale operations (and anything over a few hundred ltrs is really a large scale operation) you guys are entering area's with some major difficulties. Trying to achieve 3 figure outputs is commercial and that is not what this site is for, but most importantly, you guys are dealing with major complex issues that require the input of highly technical information.
Another point is that once you enter a large scale plant, heating a Retort is probably not the best way of going about this. You have little if any control, which one of you has already found out. You need to be looking at modern high throughput methods of pyrolysis, using what is called FVT. Fast Vaporization Technology. That is done using methods such as Plasma or Microwave to instantly vaporize the feedstock with a high degree pf control. In a large scale plant, only Tyre's are still melted using a furnace type retort.

[Excalibur]

I`m also thinking of catching the gas inside a inflatable container,don`t know if it will be suitable for gas storage, will still have to research it if I can find something suitable.

VAST
I studied the gas storage topic (aka gas jar) extensively before deciding to go with the setup that works on a "displaced water principle". I also looked at compressing surplus gas into a cylinder however I didn't move ahead with that as my current setup worked well enough for my needs.
Firstly I recalled the floating drum idea that was common on biodigesters and I proceeded to look for suitable vessels. Failing to find a pair of vessels that fitted each other, was big enough and affordable enough forced a rethink.
Then I decided to use old tractor tire tubes, ganging them up perhaps in a stack. This also proved a problem with the lack of redundant tubes being available. A similar plan to use an old (10yo) waterbed bladder failed because the plastic had deteriorated.
Finally I hatched a plan to store the off gas by displacing water. I realized I could use any sized vessels by ganging them up. I started by using steel drums but it soon became apparent that rust was going to make their lifespan too short. About this time I acquired for free some plastic 200L drums and 400L stainless bunds. This setup can be seen on one of my DIYDiesel blog pages called "Gas jar and cylinder, Orion3". Also one of my Youtube videos features a short clip of it.
Should you research gasjar/gas storage with Mr.Google, be sure to add the terms floating drum, biogas storage, biodigester, gas jar, etc
HTH.
BTW, smart thinking to plan ahead with regard to reusing parts of the plant in later upgrades. My current plant is iteration #6 and it still uses a couple parts from as far back as iteration #2.

[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.

[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.

[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]

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.

Yep, there's plenty of scope for confusion in this thread
To be clear I was responding to VAST with regard to continuous feed WMO systems as per the earlier posts referred to. A drip feed flash evap set up if you will.
Agree about the water problem. It would turn to steam with a rapid expansion rate. It might be best to preheat the stock to 110°C to evap the water. if there was any appreciable light fractions present these too would come off with the steam but could be recovered.

[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