Building a KISS Gasifier

K.I.S.S. Gasification (Keeping It Silly Simple)
A lot of members have done this on the their builds in parts or in the tire build.
A good example is the simple fire Charcoal Gasifier by Gary Gilmore.
The purpose of this topic is for the members to put down here some of your K.I.S.S. Ideas you have had and have proved that it works by it simple build and performance.
I would like to have all these ideas on one thread if possible by the DOW members.
This not the place for theory but proven building facts that work.
Like Wayne’s hopper lid cover.
A simple clamp ring cover lid.


I think the Mini Joni is a great example of KISS. One nozzle, fixed grate, can be made from pre-existing shapes(propane tanks, barrels).

Doesn’t require too many fabrication tricks to build one either.

I don’t know who started it but when I saw JO use bearing races for restrictions I really thought that was KISS.


JO’s ash/char cleanout on his Volvo WK Gasifier is all K.I.S.S in design. A round pipe tube extended out the side bottom of the Gasifier with a can to fit tightly over the pipe to seal it.
Light weight as much as you can go.


TLUD mated to a gasometer. There you go! Pretty simple, if you capped the top off and used the gasometer to pull the gas it would settle the tar out and be clean for use.


Ok this is actually part of the gasometer system. But since the shoe fits perfectly here I’m posting it here.

So Ive been conceptualizing a design in my head for some time now. I have the gasometer system figured out. I could use one, two and team beyond. Some systems may have as many as four 55 gallon drums. This is for higher demand system where the gasifier would need to be far ahead of the application as it is using the gas. So for instance, as the gasifier is filling one of the barrels the application will need to burn through three of the others in que before it makes it to this one being filled. So there will be settling and cooling time.

So that part is figured out. But how to build a simple gasifier that will have a high yield of charcoal as a byproduct as this is part of design criteria. I started out thinking of possibility of a simplified imbert, FEMA or a modified TLUD design. I had ideas of a dolly system for rolling it around plus a lift system that would allow for easy change out of the charcoal collection barrels. But I have to wonder how simple can we really build a gasifier for the purpose of storing gas and making charcoal? Does it really need to be all that complex? Can it be even less complex than a FEMA?

What if I simply make the collection bin a stupid simple low cost gasifier instead and since this would be so low cost and simple you could make many of them and just swap them out. You could have like four of them. Then in use you could fill all of them up at the beginning of the day and simply swap them out as they are processed. Its just a simple hose connection to change them and then you cap them off.

Four of these 16 Gallon drums at 40 to 50% volume yield of charcoal would very easily provide enough charging power for typical off grid application daily.

So my simple concept is simply a barrel drum with a single nozzle at the bottom and a simple exhaust port with an aluminum hose quick connect. It would need a stand to get the nozzle intake off the ground and so you have access to light it. But that is basically it.

Will it work? That is the question, all this has to do is make combustible gas it does not need to be clean as that is the point of this system. This will not have a blower system either I plan to use the gasometer to pull volume through the gasifier. On light up will activate into accumulate / extraction mode and pull on the gasifier until full and then it will check the gas by simply opening up valve with a flaring cup. So gravity pulls it back down gas come out and if it lights, it it will back to extraction mode until full.

There will be a check valve flash back arrestor leading to the flare cup.


Very interesting concept Matt. And so simple. I like it.


Bob, not important and not that it was needed but I have replaced the pineapple can with a rubber cap.

The idea of a combined drop-box and char-dump partially came from your integrated sloped drop-box, which Chris made. Also, if I remember right, his little oval gasifier is made the same way. Only, I believe Max had something to do with twin cyclones ending up inside that drop-box, which kind of interferes with the KISS concept :smile:
Maybe I haven’t quite made them to specs, because of not enough room, but none of my cyclones have worked very well. Judging from the amount of soot in the cooler the Volvo drop-box works much better.
Another reason for that could be this gasifier is different. With the tiny charbeds I’ve used before, they may pull oxygene further down and act more like a charcoal unit. Kristijan have mentioned several times there’s a difference between soot and char dust. I still don’t quite get that, but it could be another possible and partial explanation.

Enough rambling. This porcelain thinking chair is getting uncomfortable :smile:


I have observed the same as Kristijan, J.O.
There is a difference between made soots, and drawn through char dusts.
Why important?
To reduce these will require different approaches.
Of course, most care not. Just spin-fling separate them out. Filter them out. Liquid rinse-wash them out.
You know though; you former paper maker, that small percentages seemingly inconsequential do add up, accumulate, stopping the whole processes. The least produced. The longer you can operate.

Then a third black-made clogger I’ve seen now. A black coarse sugar-like granular building up in rapid heat removing exchangers. Produced gas to pumped water exchangers.
Soots are nearly pure carbons.
Char dust still has a most of the original woods cell walls minerals in it.

Physical structure changes analogies observable would be evolving degrading snows.
Sugaring; as in candies making.
Kristian is an advanced cook. Kabul too.
And you have plenty of months of snows to observe. Fluffy dry snow a pain in the ass to move around. Late evolved ice granular snow; heavy, packing, sweat making to move around.
In between these is the just right, easy removal snow.
Steve Unruh


Yes the white thrown is a good place to collect one’s thoughts and put them all down. It is as good as the armchair designing and thinking things all out.
Yes the drop box is a good design. Here is a another thing I have discovered and that is the ash/char trap in Wayne’s design. He has a drop area that is pretty much free of turbulence gas flow. This give a place for the char/ash to settle. Mine lacks this, but yours has it because it is flat and mine is sloped up and not all the way to the bottom of the main gasifier. You have natural dead zone in ours like Wayne has. The gases flow the shortest route when traveling by a vacuum flow. My new gasifier unit has this design included like yours. With a clean out that reaches the whole area below.
Yes Chris had the idea except with slycone filters added.
I am still trying to figure all the welding steps you did to get to the finished gasifier you built. Like Steve said you were welding things up that can not be taken apart after it was welded. So it had to be done right the first time period.


Yes, the most difficult part is to figure out the steps to take while fabricating - not to paint yourself into a corner. You’re right, I have skipped quite a few steps by welding things shut. Thinking things through to have everything serviceable is more than my weak mind can handle. Worst case I have to cut things open to get to the grate for example. On the other hand, I don’t have to worry about seals.


I like them. They bark like dogs and balance beach balls on their noses.


JO, the difference is the dust is charcoal particles breaking or grinding off, and travel with the gas together with ash. Some sources report this to be quite abrasive to the motor, but luckly it filters real well.

The true soot is produced when the tars and gases burn incomplete in the gasifier. Think of candle soot. The particles are extremely small and contain no ash so no realy harm to the engine, its just nasty to look at. Good thing, as its preety much impossible to filter out completely. It will pass trugh the filters whenever there is some moisture present.


Kristijan, I kinda get that part. As usual I may have meant one thing and wrote another.
What I really meant was the claim that a raw wood gasifier produces only soot and a charcoal gasifier dust. I don’t see why a big difference. Moisture in the gas? So, if you happen to feed a charcoal machine excess water drip - does that mean you’re safe when it comes to abrasiveness in the gas?


Ha, you tricked me to look my spelling up :smile:


I think the reason is fuel production. When we make charcoal, and grind it, the surface is full of charcoal dust and fractured particles. They then flake off in a gasifier.

With raw wood the charcoal gets produced in the actual gasifier. There is not much grinding action. It just gradualy burns away.


That’s the problem with English JO. The same word, spelled the same way can have multiple definitions. I’m amazed you guys can maneuver your way through it. I once spoke German but after so many decades of non-use it has mostly faded now. When I was 20, and still an apprentice, I got a supervisors job erecting an automated cement block factory from Germany. I was the only one that could read the blue prints. They did send a guy from Germany to oversee the job but he was so arrogant that no one could stand him and his English was not great.


Tom, to tell the truth, there is a reason why almost everyone today speaks at least some English. Its so simple :smile: hard to explain but compared to say slavic languages English seems almost primitive. Not to offend anyone ofcorse. Im saying our ancestors did a good job complicating things :joy:


Good Morning, ALL.
I’ve had problems reading this topic as I’m afraid it would just recreate a FEMA type in construction and performance.

I linked back to BobMac]s opening statements:
“The purpose of this topic is for members to put down here some of your K.I.S.S. ideas you have had; and have proved that it works by it (being) simple (to) build, and (proven) performance.”
“Not the place for theory but proven building facts that works.”

So, the title means, “Building a Gasifier: KISS”

For the longest time I was insisting from experiences that woven fiberglass stove rope would seal airtight. It just took using the larger diameter rope; with a made rope holding channel; and opposing raised compressing bead. Ha! Ha! Most ignore the opposing squeezing bead. Versus a flat surface squeeze. These will unevenly squeeze. And with use, wear, leak.

Another of mine after too many times multi-bolts flanges assembling, and disassembling, I have insisted that joints can be made flange-less. V-Band clamping. The barrel top method.
Or use external welded onto the housings U-legged lugs with a single pull tight bolt and nut. Three pairs. Four pairs if you just insist.
Flangeless. Right down to piping with the off-the-shelf; or scrap repurposed vehicle exhaust manifolds, to pipes, pieces. V-band clamped; or ball in socket types, three bolts drawn together.

And one KISS I saw Ben Peterson evolve into was learning to effectively build with zero cone shapes.
Joni and others do zero cones too.
WayneK does thin metals, no-math’s, overlapping slits forming for slopes.

My wood stoving experiences says line the center core-of-hell with loose fit sacrificial insulative purpose manufactured stove bricks.
Some have now done this on their gasifiers. My next from scratch builds will too. My current is too internally small to retrofit.

So KISS in constructing does not have to mean FEMA no-air-nozzles shit in performance.

Regardless of my personal opinions for serviceability; all-welded up can be performers too.
Aught to use Kritijans heavy plate building going all-welded up imho. That learned from lots of hard ran woodstoves too.
Thin metals all-weld-ups soon use evolve quickly into fix-and-patch, weekly. Or throw out, make another. Better be quick to make. You’d better have access to more, cheap/free, available makings.
Steve Unruh


My late father repeatedly said, “if it was that simple it wouldn’t be waiting for me”. It is not really easy to produce quality gas from wood, at the moment I imagine it this way, two different barrels, a brake drum, a brake disc and a hose in the middle to supply air and pyrolysis gases to the hot zone.


This is similar to what Kristijan and I were talking about a couple of years ago. A way of circulating the upper hopper tar/H2O gases back down into the Charcoal hot zone to be completely burn up and changed into CO, H2 gases. But with out cooling the reduction zone down to much. Wood gasification has a surplus of moisture to deal with. This why the need for hopper cooling tubes for condensation and tar/water condensation cillection tank to collect the extra amounts. Also the need to keep the nozzles open and not to plug up when the gasifier is shut down a cooled off.
This just might work Jan.