Retort Kiln Afterburner

Hi, I am brand new to this forum and glad I found it! I built this retort kiln and it works really well!….well, except for the 45 minutes of smoke and the fire department calls :grimacing:. I’ve been starting batches at night but would rather get it going earlier in the day and maybe run a couple batches each day. So my question is how would I set up an afterburner for this type of kiln to burn off the smoke before it exits or at least a lot of it? Any tips for mods would be hugely appreciated :pray:

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Build this instead, only reason it smoke here in this video is because I lit it using pine needles. Otherwise smoke is minimal as long as you keep the layers maintained it will hardly smoke at all and you can keep making charcoal all day long with it. It is not a batch machine.

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I think if I stack a second set of barrels to double the dwell time the raw fuel is heated I bet it will be more efficient. This fall Ill be building a number of new kiln technologies.

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Hi Jamie,
I live in Colorado, where it is very dry. So getting dry wood is no problem for me. These TLUDs (Top Lit Up Draft) work really well for me. I started out making them out of old coffee cans. This gave me really nice small quantities for the barbecue.
Then I got an old hot water heater. I just use the tank there are no internals. There is a grate in the bottom to allow air in. The coffee cans on top are the very same tlud I made before, but rearranged with the air holes at the bottom. I get about 30 gallons of charcoal out of the 50 gallon tank. I use the charcoal in my forge and to make gas for my generator. I haven’t had any problems with tar getting into the generator.
I recommend learning to make camp stove sized tluds first. Ask me any questions.
Rindert





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Thanks guys I can see I will learn lot from this.

Matt, your design looks like high yield and low smoke for sure!

Rindert, you’ve got great stuff too!

What I’m seeing from you both is that the charcoal in the kiln doesn’t need to be isolated from the flames to become charcoal. Is this how you guys are achieving the high yields with less smoke?

Rindert are you manually putting out the flames or cutting off oxygen on your yield?

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Yes both are direct fired TLUD designs. My version is modified slightly to close off the top to force the pyrolysis gases into the combustion zone and full burn out the vent holes as the gases migrate out into the shroud. Then then mine has a grate designed to drop the fuel out into the bins. Other than these mods it works exactly like a TLUD.

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That’s right. I take the bricks out from under the tank so it sits on the ground, and I put a little dirt around it to seal up the air inlet as much as possible. Then I take off the chimney/afterburner, replace it with another coffee can (just a lid really). I seal around the base of the coffee can with mud.
Rindert

PS what actually happens in a tlud is the fire separates into two parts. The afterburner keeps burning while the primary burn works its way down through the stack of wood chunks. The volatiles in the wood cook out and are partly burned. Hot gasses from the primary burn travel up through the newly made charcoal to the afterburner.

I hadn’t yet thought of putting mud around the coffee can in this picture, and I have also started putting a 5lb rock on top of it just so the wind doesn’t knock it off.

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