Incinerator Design

[gaurav_347]

Members,

I am planing to fabricate an incinerator just for ics and chips. The design is based on an idea I got from youtube. I am planning to replicate it but in a smaller size. I will post the link below. The dimensions are as follows:-

Outer dimension - LENGTH 1000MM WIDTH 1200MM HEIGHT 1500MM
Workable dimension- LENGTH 400MM WIDTH 450MM HEIGHT 600MM

The YOUTUBE link:-
https://www.youtube.com/watch?v=ItUgmYoTTUs
This incinerator will be working on waste oil burner or LDO with 1hp fan motor.

I need your valuable comments and ideas for if I should make any changes in the design. The batch size will be 10-15kgs. The chimney will be connected to the centralized venturi scrubber for scrubbing out the fumes. The whole project is costing me roughly USD 600. We can increase the size with marginal increase in costs.

Thanking you,
Gaurav


edit- cant seem to embed youtube link correctly

 

[Gratilla]

Gaurav,

I'd seriously consider pyrolysis (heating in the absence of oxygen) rather than incineration (burning in air/oxygen) for this kind of project. If done properly, you'll get a cleaner (metal) product at a lower temperature.

A lot of info on youtube and via google.

Gratilla

 

[Lou]

Pyrolysis first at 450, then controlled oxidation of carbon no higher than 650C. You know the drill Gratilla. Then mill, then off to the races.

 

[gaurav_347]

Gratila and lou,

The incinerator will have two switches. One to start the burner and the other for the fan motor. I can probably do this. First start only the burner and heat the vessel in which the chips will be kept in. Then as lou suggested oxidize the chips with the fan switched on. When they are white remove them and ball mill them.

Regards,
Gaurav

 

[4metals]

The burner in the video doesn't usually burn without the blower running. You will not be really pyrolyzing the charge in this type incinerator.

 

[gaurav_347]

Sir,

Why is it necessary to pyrolyze first then go to incineration? When the ultimate goal would be to incinerate the material in the end? What I have learnt through some posts on the forum is that the ultimate goal is to burn off the carbon as carbon will hold values that's exactly what incineration will do too unless I am wrong somewhere as these topics are fairly new to me. We are making changes in the design where we can toggle between the blower and the burner or run both at the same time.

Regards,
Gaurav

 

[FrugalRefiner]

Guarav, when you heat these materials they give off all kinds of volatile, toxic substances. Pyrolizing the material first will drive off the volatile compounds. This gas should be run back into the pyrolizing flame or through an afterburner to break them down into less harmful compounds. Once the volatiles have been driven off, you can incinerate to burn off all the carbon.

If you just incinerate the material, much of the volatile material will go up with the exhaust gas, escaping into the atmosphere and poisoning everything around you.

Dave

 

[gaurav_347]

Sir,

Thank you for your reply . The incinerator chimney will be attached to the centralized venturi scrubber system to scrub off the gases. We have to go according to the pollution control board norms so we are taking all the safety and environmental measures while proceeding ahead.

Regards,
Gaurav

 

[4metals]

Years ago, I had a large incinerator which was set up just like the one in the video. It had an afterburner with the suggested retention time and temperature, and a wet venturi scrubber. It excelled for things like jewelers sweeps and brushes and wheels from polishing but for circuit boards it was horrible. It is hard to imagine how much they smoke. To put this in perspective, we could easily burn 750 pounds of sweeps with no smoke out the stack. Printed circuit boards had to be fed 2 pounds every 10 minutes so as not to overwhelm the system.

You could fill a drum, which you can seal up tight and place in the burn chamber, with circuit boards and have a small vent hole in a position where it will be in contact with the flame that will heat the drum. The drum will heat up for the pyrolysis and the volatiles will exit right into the flame to be burned. When that process is complete, the material can be incinerated without the drum to get rid of the carbon without smoke.

 

[gaurav_347]

Sir,

In my previous pm to you I had mentioned that we have a depopulation process in place where the machine depopulates the boards completely and the components are manually sorted. The solder and small components like mlccs are collected at the base of this machine. The incinerator that we are fabricating will only have one purpose that is to incinerate ics and chips. For the depopulated boards there is a mechanical process where copper and epoxy are separated without any use of incineration.

The incinerator in the video is quite large for our purpose. We are actually scaling it down so that it can accommodate roughly 10-15 kgs of ics and chips per batch. I can probably make a box with a lid which could fit inside the incinerator. We can load the ics in that first for pyrolysis and then as Lou suggested incinerate it by letting it oxidize by opening the lid of the box a little. The fumes generated will pass through the scrubber system.

Thanks and Regards,
Gaurav

 

[Gratilla]

Pyrolysis first at 450, then controlled oxidation of carbon no higher than 650C. You know the drill Gratilla. Then mill, then off to the races.

Lou,

1) The reason 650C is quoted as a maximum is that the melting point of alumini(u)m is 660. And molten Al will mess up results. All hydrocarbons will gasify below 600C, so a max of 600C will give a wider safety margin.

2) Commercial pyrolysis systems introduce controlled amounts of oxygen via steam (ie H₂O). So:

C + H₂O = CO + H₂

This mixture of gases is referred to as syngas (ie synthetic gas).

Gratilla

 

[Tomd]

hi all im new to this forum and pretty new to refining but i am a furnace engineer so sure i can help with this! the simplest solution is to to use a 2 chamber design to controll youre emmisions. the first PCC (primary charge chamber) will drive off volotile compounds with a lack of oxegen (air) then pass this into a SCC (second chamber) with a seprate burner and an ample supply of oxygen to finish the reaction. The design of the second chamber should include some form of baffles to ensure a good mix of gasses and complete combustion. this second chamber must be pre heated prior to any charge being introduced. Anything over 800c ishin the SCC is more than enough to deal with what you need but this temp must not drop below 800 or you will not be completing combustion. Hope this helps if you have any questions on my desdign please feel free to ask. Tom

 

[gaurav_347]

Thank you Tomd for your suggestion. The furnace top chimney will be attached to the scrubber system.

 

[gaurav_347]

one more

 

[gaurav_347]

The finished incinerator in action !

 

[Gratilla]

The bump gives me an opportunity to expand on my previous post.

To Keep It SSimple, I'd:

1) Place carbon-covered product in air-tight chamber.
- Optionally flush chamber with nitrogen; this is not completely necessary if your chamber is fairly full as most oxygen will be expelled when you heat the chamber.
2) Heat chamber to between 400-650 deg C. This a will gasify all the hydrocarbons.
3) A pipe from the chamber can be used to flare off these gases or they can be fed to a distillation setup to recover most gases (ie not propane butane, etc) as a flammable liquid.
4) When no more gases exit the chamber/pipe, the cycle is complete and you should have clean metal left behind.

Some people have "discovered" pyrolysis for recovering copper from electrical cable. Burning (ie the current standard method) still leaves behind a black gunge; pyrolysis will leave clean copper ready for recycling.

Gratilla

 

[myfalconry76]

one more

Hey I have one of these I picked up with a load of scrap metal about a year ago. I thought it was a antique gas furnace or weird wood stove. Yippi I got a incinerator. Wich is what I was going to use it for. Cha ching

 

[gaurav_347]

@Gratilla

Sir once the doors are closed of the incinerator only the lpg is burned provided we give some external air with the blower attached. If we switch off the blower the flame dies out due to lack of atmospheric oxygen. So in short whatever air that we are providing is for the lpg gas to burn along with the oxygen. After 15 mins or so we open the door just a bit for the air to enter the incinerator.This helps in turning the ics or chips to burn off completely turning into white and brittle. The gases are scrubbed off with the help of a venturi scrubber to scrub off the gases.

 

[gaurav_347]

@myfalconry76

A year and a half back i had got a chance to pick up 6 tons of ewaste from a University in my city. I lost the bid due to the fact that there was an incinerator involved. i dint know what it could be used for. I bid a few 100 dollars low because i didn't know the real usage for an incinerator as i was new to the forum. I regret it till today! it's good you got a chance! make use of this great community, learn everything you can and then learn more!

 

[Gratilla]

guarav, you're over-thinking/over-complicating the process. Also you're incorrectly applying incinerator technique to pyrolysis.

The Keep It Simple and Safe design is as described above - an airtight steel reactor chamber/container and an exit pipe; I'd suggest at least three meters in length. Place mixed hydrocarbon/plastic-coated pins and things in the container, clamp up and apply 400-650 deg C of heat. First the plastics will melt (at different temperatures depending on the plastic) and then gasify (at different temps ...) and exit the flare tube. It is intended that ALL the plastics gasify and flare, not JUST into butane/propane/methane - which are gases at room temperature. The flare, actually, is a quick test for when a cycle has finished - all the plastic will have gasified and exited the container, gas will stop flowing and the flare will go out.

You do not need to premix air/oxygen with the gas flow in the tube; air/oxygen will mix adequately at the end of the flare tube. You definitely don't want to premix air/oxygen in the reaction container as this is dangerous and risks explosion!

The end result we hope will be a bunch of clean shiny pins and things and NO black gunge.

If you insist on separating the flare gas into its component gasoline/kerosene/diesel/tar etc then you need to get into distillation, for which there's lots of info on the web and youtube.