Feasibility of Rectangular Charcoal Gasifiers

Here is how I did it on my 9 1/2 inch wide container.

I only ran it for a little over a half hour or so yet but it does not burn the paint off the container yet
I did put in a close nipple instead of the 3 inch nipple like Gary Gilmore suggested.


Do you have anything holding the refractory bricks in place? or did you just set them in? I would be worried about them shifting with the bouncing of the tractor, but that won’t happen as much if they char is packed in tight enough to hold it in place. Trying to get a bracket to hold them roughly in place through the hole would be kind of like building a ship in a bottle though…

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I used that high temp latex fire stop caulk that Tom C recommended. Also the bottom firebrick are cut between the vertical ones for a wedging effect and like you say the charcoal also has some effect in holding them in place. Time will tell. So far so good.


That should last for a while, save the patterns for the bricks, I have a feeling you will need to replace them at some point.

Bigger tires will help too, they smooth out the ride. Turning it into a “Monster Char” especially with a glossy black paint jobs with flame detailing, is more work then I would put into it though. :slight_smile:

Hi Don,

Was the 1/2 hour time the run capacity of the gasifier? What are your tank dimensions?


the bottom of this thread has the tank used. Although he gives the dimensions earlier in the thread.

My tank is the same as Sean pointed out, 16 1/2" wide, 9 1/2" deep and 28" high. There was a depression in the charcoal after a half hour run time about 6 inches in diameter and tapering down about 3 1/2" and then a gradual rise to the four corners. I would estimate that I burned up about a gallon plus or minus in that half hour. This depression was pretty close to straight above the end of the nozzle which tells me that I could have used a little longer nipple to center the burn cone better. Without a lot of experience using charcoal I would say my setup would give 1 1/2 maybe 2 hour run time before half the fuel is used which I hear is a good time to refill.


I’m glad to report that we are shooting for the 8"x36"x36" gasifier, and we are moving forward with the gasifier workshop - Facebook .

Does anyone have technical plans available for a continuous DIY charcoal production system? I’ve seen the discussion at Making charcoal continuously - #8 by freedombiomass . We are considering a taller system that augers wood into the top, and augers charcoal out the bottom. But at the same time, it would be nice to wrap a helical 1/2" pipe heat exchanger around the flame for house heating. That would be great for winter house heat with combined fuel generation for MicroTractors and MicroCars.


Hi Marcin, do you have a sketch up of why the unit must be that narrow. At that horsepower you will be bleeding a lot of heat that could be used for more productive purposes. Good luck with the build.

Hey Don,
I am just now getting caught up on all the post from Argos meet up I was camped next to you in the Aline camper I was so busy trying to see every build that I didn’t ask enough questions or get enough details of your tractor .I brought some tig nozzles to experiment with in Garys’ gasifier and my 100# propane tank gasifier we both had failures due to heat and the only thing I could find to match up with black iron pipe and the nozzle was a brass nipple the brass can’t take the heat so I am wondering if I wrap the nipple and nozzle with stainless or I bought some fire clay make a cylinder over both I am looking for longer run time
Thanks, Dan Moore

Hi Dan, I remember Gary waving a melted Tig nozzle in front of me at Argos but we didn’t talk about it only to say that he was disappointed with them aqnd would be using stainless after that. How long did the Tigs last before they melted? Did you use exhaust to temper the heat? I am still using the first nozzle I put in when I built the tractor. I use exhaust to cool and add CO2. I rode around a lot at the steam and gas show Friday and have maybe 7 or 8 hours run time on it so far.

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Hi Marcin, I have been thinking a lot about a continuous small scale charcoal producer that can capture the heat. The best idea I can see at this time is a basic WK wood gasifier. Wood enters the top, gets reduced by fire at the air nozzles and produces clean wood gas as it desends the hot fire tube. This design will need a grinder where the grate is located to crush and remove the charcoal from the tube. This charcoal then falls into a hopper and carried away. The wood gas created in the process can be used to run a stationary engine or fire a boiler. I suppose you could wrap a water coil around the fire tube, but this heat may be necessary to completly char the wood. The water coil could cool it too much. Maybe.
Another idea is to have a fema syle gasifier that is open to the air. Wood is dropped into the fire tube as fast as the charcoal is removed from the bottom. I have made a version of this, but got side tracked on other projects before giving it a test. Still sitting on my shop floor two years later!!! I really need to quit getting so many ideas or else retire and have more time.
Later, Gary in PA


Hi Gary, do you have any pics you could post or send? I ask because I’m torn between that FEMA type for heat and charcoal production or one I say in Doug brethower’s book; fire up tip coal sink and cool, augered out from the bottom…
Thanks, David

I wonder if an ice maker auger and crusher would work for charcoal?

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Don, I think Gary ran his for several hours and I had trouble with the gas flow when I took it apart I found the brass nipple almost melted and the nozzle had what looked like slag on it my reducer was also starting to burn up Gary told me that he thought the brass nipple could not take the heat that is why I thought maybe wrapping the brass and nozzle in stainless or using some fire clay to protect it .The threads on the black iron fittings and the nozzle are diffrent one is pipe thread and the machine thread I think .We ran the exhaust back into the the tank.I have diffrent size nozzles but they will need to be reduced to be used the experiment is to see if diffrent nozzles would give a better gas flow and would they last longer than black iron wrapped in stainless

Hi Marcin, I’m curious how the workshop turned out. Care to share some highlights?
Best regards, David Baillie

Keep in mind that silica based refractory cement has a catalytic effect that promotes catastrophic oxidation of metal. So make sure that the metal is coated enough to keep the air, heat and catalyst combination from eating up your metal nozzles.

Well Mr.Dan, I had a little time this afternoon so I removed the nozzle to take a look at it and it was gone! - along with a inch or so of the black pipe nipple it was attached to. I’m not sure if the black pipe burned off and the ceramic is laying down in the ash or if the ceramic melted to nothing because I didn’t empty the charcoal to remove the nozzle. I have been noticing longer startup times and harder starting. I guess I will try the sacrificial stainless nipples and see how that goes.


After attending Arkansas last fall and seeing what happened with Al Denninger’s stainless steel nozzle with larger charcoal, I’m wondering if you used the same set up but made smaller feedstock if that would stay intact? After reading about the Kalle system, he stated the smaller the better.
Also I forgot, are you feeding some exhaust back into the air inlet?

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What happened to Al’s stainless nozzle? What size charcoal did he use?
Yes I add exhaust to temper the flame.