Tlud analog? Easy to make " reactive" furnace \ stove

I keep seeing these Russian videos on YouTube about a wood burning stove that is called a "reactive" stove or furnace:
   

One video says it is totally unique but it seems like an a analog of a tlud to me  but its a bit different.  Instead of the secondary air being delivered via holes around the top perimeter, it has a center opening  for secondary air. Its more similar to the tlud design made by Paul Olivier which also has a center pipe for secondary air. ( picture attached)

Here's more info on Paul Olivier's tlud design with center pipe secondary  written by "Tim Tinker " : https://tinkersblessing.com/tag/tlud/

Although in Paul Olivier's design,  the pipe air has holes only at the top.
But with the "reactive stove", the secondary " pipe" is mostly open along the whole length.. It is a cylinder made from spaced rods that supply air and also to keep out sticks.

This design seems really easy to make. Today I am going to make a prototype from a gal paint can . if it works good. I will make one from refractory material and insulate it.

I tried to find this design on this forum but I have not found it. The secondary air ( and flame intensity )can be controlled with a valve.  I'm just wondering if anyone here has tried these and if there are any drawbacks? Also wondering what ever happened to Paul Olivier's center pipe secondary tlud? Why is it not more popular? It seems much easier and simpler to make than the double walled tluds with secondary air holes around the perimeter.
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These stove remind me of sawdust stoves, in that they have a central chimney for combustion.
The flame front can proceed from the center out to the perimeter of the cylinder, instead of from the top down.
They also resemble the swedish torch in this way.

If there is an advantage over a typical tlud I think it would be due to less care needed to process and load the fuel.
Tluds do not need to be doubled walled , they work better with it but fine without  that feature.
If you feel like you need it, it's not hard to create.

The Paul Olivier design has primary air, secondary air and the central chimney.
It could be argued it uses less in the way of materials than a double walled tlud, but he seems to rely on  forced combustion air.

The "reactive" stove seems to tightly control the combustion air, and it's a "natural" draft stove.
The way the video built the central chimney seems unnecessarily fiddly.

A stainless steel stock pot with a NPT male threaded steel nipple would be a good start for a reactive stove.
Compatible with plumbing hardware, the npt threads would make adding a valve to control combustion air pretty straight forward.
For the central air "pipe" , a steel silverware holder is heat resistant and comes with perforations.
I think we can call this a vertical  tuyere, since it serves much the same purpose.
Inverted over the pipe nipple, it should keep the fuel from closing off the combustion air.
Cut a hole in the lid and your done.
I do think the stove in the video could benefit by a short length of flu pipe with some secondary air holes, so maybe add the that.

I bet this would work great with sawdust.....      Something I would be interested in seeing is if the air coming in would be at an angle if a vortex could be created.....

Would be useful for creating charcoal as turning off the air would be easy with this design...

Here is a "sawdust" stove that is burning leaves instead of sawdust:


It's in Russian, but if you skip ahead to 6:40 you will see it in action.
Total burn time is close to 4 hours.
Like most of these stoves the central chimney is formed when the fuel is packed around a pipe that is then removed.
If we used a vertical tuyere, the packing process could be less fiddly.
In particular, I think it could burn wood chips that are just poured into the fuel chamber.

I watched the video again......  ( from the first post )    and I do believe they are using a fan to push the flames....    The reason I say that is you see flames shooting out the cracks on the top of the stove....   this is not normal as it would normally just go out the chimney...    

I think a fan would be a good addition, but if they got the flames that big they should also show how they got them....

If using a fan, then these may basically be an "inside out" version of the T. B. Reed et al "Turbo Wood-gas Stove" TLUDs.

I've tinkered with natural draft TLUD stoves made from soup cans, but combustion wasn't particularly stable - they were either "up on plane" and burning cleanly, or were smokey and drafting poorly.  A small shift in the fuel load as it settled during combustion was enough to upset the apple cart, though I never tried fueling them with pellets, which would have a more consistent particle size and likely a more consistent draft and settling behavior.  The small branches and twigs I was using, cut up into short lengths, also probably had variable moisture content.  The small diameter burn chamber (and especially relative to the characteristic size of the fuel load) really was rather twitchy.

I suspect that a small forced draft fan (as I recall, Reed spec'd a 3 watt model) would probably help to ensure more stable combustion with a less consistent fuel.  I'd think the same would be true of small inside-out TLUD-ish stoves like these reactive stoves.

The bubafonya stoves are another Russian (Siberian) development, though not a gasifier, and so less clean-burning, as best I can tell.  But, they are pretty low tech, and long burning.

I'm currently working through the Alex Berberich online course (through Bosco di Ogigia) for constructing a pyrolyzing gasifier thermal mass heater.  Fancier burners than these reactive stoves, and definitely not a rocket, but still basically a TLUD, though relying on a chimney for draft.

Kevin, I love those stoves!
Home heating that produces charcoal is my jam!
This video introduced me to the product:

Mart Hale wrote:I watched the video again......  ( from the first post )    and I do believe they are using a fan to push the flames....    The reason I say that is you see flames shooting out the cracks on the top of the stove....   this is not normal as it would normally just go out the chimney...    

I think a fan would be a good addition, but if they got the flames that big they should also show how they got them....

I kept watching more of these reactive stove videos and I think we are just seeing natural draft.
Here's another one, it uses pellets but it's design is the same as the other one:


@5:59 onwards we see it in operation, it has a strong collum of flame with no forced air in use.
A well made natural draft tlud is pretty rockety, these stoves just might be the better version of a tlud.

I remembered another variation on this kind of gasifier with a central chimney.
Its called an Anila  stove:
https://youtube.com/playlist?list=PLUQMDg9HfMjhO4EmOInCOqCrcy1K_9LMm&si=UwChtIKQx3wA7Lpn


They are quite similar to the reactive stove design, but they don't use an air control valve and they actually make charcoal!

William Bronson wrote:Kevin, I love those stoves!
Home heating that produces charcoal is my jam!
This video introduced me to the product:

Yes, this one "set the hook" for me, but what "reeled me in" was his conversion of a wood burning cook stove to a pellet gasifier:



There are a zillion old cook stoves around my neck of the woods.  Conversion to a cleaner and more efficient combustion method seems worthwhile, if only from the vantage of reduction of fire hazard.

I don't know that Alex's thermal mass heaters are really intended to produce charcoal.  But, since both the primary and secondary draft controls are within the operator's purview (throttle and mixture), tailoring combustion toward residual charcoal should be possible.

Wow, thanks for all the replies and different designs. I started making my 1 gal paint can prototype but I got inturupted for a few days so I'm still working on it.  Thanks for the designs tips, William  . I just happen to have a duct connector ( reducer fitting) ...the big end is ths the same diameted rs the gal can. I will put secondary air holes in it.

Oh yeah,  it does seem like there's a blower being used after seeing the flames come out the outer cracks like Marc pointed out.I was actually planning on trying to make it forced air anyway. I have a little blower fan with speed control. I think its 15 watts ( max).

The Anila stove is interesting. I was wondering if it can make enough charcoal to later use that charcoal to burn in the stove instead of wood?  I know its designed to burn wood clean, but charcoal is even cleaner. I would rather cook on charcoal. If it makes a bunch of charcoal, why even bother burning g wood in it to cook with ? ( and make more charcoal at the same time).  

I'm going back and forth on the forced air thing.
I don't think we can know for sure without trying for ourselves.

I used a mattress inflator for my forge build.
They are easy to come by and they run on DC.
It's easy to match pipe,hose or conduit to their round exhaust.

Many have used wood burning stoves to dry fuel for itself, but getting the fuel too close results in unwelcome combustion.
The Anila courts that combustion.
The refined fuel (pellets)that is in the center of the stove burns hot and clean,  and the process heat turns the random bits of brush into charcoal, a refined fuel.
I believe using charcoal as the fuel would work, allowing us to skip the use of pellets or other refined fuel.
The idea of using charcoal to make charcoal has been on this site before, but I think it revolved around heating a retort filled with feedstock.

The Anila stoves have only a few holes at the bottom of the central stack.
I think that might be necessary to keep the feedstock from burning to ash.

I'm putting some bits together to build a stove.
No holes cut yet, just messing about.

The plan to use to stainless steel bolts and nuts to affix the silverware holder in the middle of the stock pot.
Air admittance and control, yet to be decided.

The lid is a pizza pan, inverted over the bean can and affixed with self tapping screws.
With a hole saw, we punch a 2" hole through the pan and into the van.

In use, the outer ring is filled with  any old feedstock.
The lid goes on, the bean can slips directly into the silverware holder and is filled with pellets or charcoal.
The center is a tlud, the outer ring a retort.
Light it off and hopefully it makes more char than it uses.

Ok, so this guy was inspired by the Anila stove.
I don't like his loading/unloading mechanism, but I do like the blower separated from the burn chamber.
He reports that it takes 4 hours of burn time to pyrolize the feedstock, and described feeding the fire during that time.
That sounds terrible to me, but there is some differences in planned uses and designs between he and I.

I want an all in one fuel + charcoal feedstock cartridge that can be swapped in and out of an outdoor boiler.
The ease of loading and unloading is important to me, because I hope to be heating my house this way  in my old age.
If he filled the center cylinder I think it would hold less than a 1/2 gallons of fuel, compared to to the nearly 4.5 gallons of charcoal feedstock.
I think a ratio of fuel to feedstock of 1 to 3 would be reasonable, assuming the feedstock looses a third of its volume during pyrolosis.

For context, a roughly 6" diameter circle has about a 4th the area of a 12" diameter circle, so a reactive stove with a 6" dia inner cylinder and a 12" diameter outer cylinder would have that 1/3 ratio.