Bamboo charcoal, indirect heated

Show some pictures how charcoal can be made.

Outside heating with waste wood, and gas from charring if you would like.

Stage 1 water vapor

stage 2 ( bamboo vinegar )

stage 3 tar and exothermal reaction and a lot pressure

stage 4 a lot of gas

stage 5 temp between 700 and 850° C ( Cherry red drum), exothermal reaction stops, no more gas escapes, ( unless you increase temperature of course )

stage 6 cooling and unloading

Charcoal has carbon content >85% and is very crisp

I will give this a little more time tomorow and edit, ( i have a real slow internet connection here 55Kbps )



I ad now a picture how the system function works ( principle )
Drums are mounted on a hollow rod, can turn the drum for stirring the content
Zone 1 Preparation and loading drums
Zone 2 First heat exposure 30-100°C, draining vapor
Zone 3 Heating between 30 and 300°C, draining vapor and first condensates, pre carbonization.
Zone 4 Heating between 250 and 600°C, exothermal reaction, draining tar condensates and a lot of vapors, gas starts to burn, carbonization
Zone 5 Heating between 550 and 850°C, useable gas , can be used for engine application
reaction stops at +/- 850°C, Drum is cherry red.
Zone 6 Unloading the drum from the rack, cooling down, empty drum if is cooled

At any stage, vapors can be collected, condensed, and fed into the fire zone
setup alows the extraction of bamboo vinegar if charcoaling bamboo.

Last yield rates from yesterday.
Input 60 Kgs raw cut bamboo,
moister aprox 20%
Volume 170 Liters

Charcoaling time from 0 till finished: 2Hrs
Weight after charcoaling, 0% water; 17,5 Kgs
Volume reduction: 120 Liters after charcoaling.

Stored outside for checking humidity increase

Video on youtube from the retort

Love it!!! Smoke and fire, under pressure too. It is funny you show bamboo. I planted some bamboo roots earlier this spring. My thought is to experiment in using it for charcoal production. The bamboo charcoal you make looks pretty durable and I’ll bet makes good engine grade fuel. The method you show creates a lot of smoke which may not be a problem in your area. I am curious if the two barrel method will give you the same yields. I know it will produce less smoke… I’ll see if I can find the results of my hardwood burns last year and see how they compare to your bamboo yields.
Gary in PA

Nice set up koen. I like the rotating rod for even heat distribution…
David Baillie

@Gary, yes bamboo works perfect.
If you collect the fumes into a barrel, then you can use the gas after condensing the tars and the liquids, as fuel for the fire, so very little smoke ( the lowest emission rates )
Its indicated in the graphic i made before. the setup here is to keep it simple. since you not burn, but cook the content of the barrel, no odors just water vapors.
The rods can be perforated to extract the gas and redirect it, same time you can rotate the barrels to evenly distribute the heat as David mentioned.
The whole idea is to keep it simple and make the locals wanting to copy it.

In a later stage i can build a chain that makes it automatic.

PS. The same presure comes inside a reactor when gasifying wood. @ 300°C 1 liter water becomes 4000Liter steam

But anyhow, this is fun…

Hi Koen,

What part of Thailand are you based? There are some videos on Youtube of industrial gasifiers in Lamphun, and some others working on them in Chiang Mai. They had a Dutch (I think) academic helping them with design.


Hi Gary H,

This is the link where i am based.

Yes, there are quit a few projects in Thailand and nearby region. But reading the analyses brings always the same point… Feedstock and awareness… and of course the import of the technology which is difficult for obtaining good maintenance.

The big projects are always commercial and not always ecological.

My project is more simple. use everything (green waste) and turn it into a useable energy with simple, understandable techniques.

Its a kind of farmers for farmers project… trigger there ego’s to copy it and to do better themselves :-p

Hi Koen,

I have been trying to get my wife’s family using a gasifier stove like used for camping made of tin cans. Trouble is they don’t see the value in it and just go back to their old ways. Buying fuel is a different matter as they have to find the money for that. Have you had any success with getting them to copy?

I have not been over your way just been to Mai Sai to do visa runs a few times. We where living near Lamphun but find life is easier back in Australia for health care and education.

Hi Gary H,
Sadly enough i wasn’t in australia yet…
The copying is starting now, and the first real visitors have been here yes
Now i am working on a tripple set up for the “road show”
1 Using the BS engine with an alternator from a car , connected with an inverter to get 220V
2 The honda GX200 with the piston pump
3 The Honda Clone with an centrifugal pump

all getting build without carburators, just with hand adjusted ball valves.
i did find some stuff to make some “improvements” on the gasifier and will post some pictures tomorow.

Here some more video’s i have made

A few stills pictures please?

Steve Unruh

Herr Van Looken,
Making charcoal does not need to be a smoky process! (I see some homes very close to your charcoal making activity.) Have you studied Gary Gilmore’s videos on YouTube showing his charcoal making scheme? I have made 124 200 L (50 gallon) barrels of charcoal following his directions and didn’t make as much smoke for all of them as you show in the 17 second videos. :wink: If your material isn’t totally dehydrated (Very dry) it is possible to add small dry material to the afterburner barrel (throw it in the top). Use small pieces of wood, or even crumpled balls of plain paper. This is a TLUD, so you want a good layer of charcoal working it’s way from the top of the barrel to the bottom. As smoke is created, it needs to pass through the glowing char, and is consumed. Here are some photos of the setup. The second photo shows the primary air inlets at the bottom. When the glowing char reaches those holes, I remove the bricks which drops the barrel into the depression, and then I shovel lots of dirt and clay over those holes. I remove the afterburner barrel before doing that, and once the bottom holes are shut off, I place a sheet of steel over the bottom barrel and let it cool down. (Third photo.) Let me know if you need more information. Ray (a non-smoker)

Hi Koen, I use the same method as Ray and can attest there is minimal smoke. If you were using junk wood for the fire and good for the retort there would be a reason but both woods are the same so there is no efficiency gain either. Here is a batch cooking this instant. I’m about to cut some primary air it’s shooting sparks…

Hi guy’s,

Sorry for the links to the video’s only…
I will repost after uploading to youtube, with the explanations.
Mea culpa.

The smoke:
Shown in the video’s is just a test setup for obtaining some data.
The next goal is to collect the fumes, and use them at the different stages.

An more optimal setup would be , as presented in an above drawing, with multiple drums which proceed on a railsystem.
The whole plan of my doing is: to use all green waste, charcoaling it in the retort system and use all resources as eficient as possible.
These video’s represent merely the first tests.

The advantage from a retort system? Higher control about the quality of the charcoal , higher yields, higher carbon contents, gas from the charcoaling proces useable as a on site fuel is 150% more powerfull, vapor can be used as water source, the condensate is a good source of energy ( pyrolyse oil )

In these video’s i do use a lot of the available material for the outside heating, nevertheless…

The dwell time for 1 drum (between 60 and 80 Kgs) to turn from wet into full charcoaled material = max 2 hours.
Making a good setup gives you a average from 20 minutes for obtaining 30 Kgs ( using a cascade system with multiple barrels)

Another advantage from the drums in retort system is, i can charcoal even the smallest particles, to use them as fuel afterwards in the gasifier. ( small branches etc… ) even rice husks !!! ( the rebuild lawnmower will be used next as a woodgas driven chipper, to chip the small twigs and branches)

It was and it isn’t the purpose to construct an perfect technical system, but for showing the people around an understandable , ready to copy idea.
Making a simple setup will give people a change to make improvements with there own idea’s and the drive to do things for the benefit of the surrounding nature.

I will post soon, but now i am testing the next trial with the KOGI 2 and the clone Honda 5,5 Hp on a water pump.

@ Ray,
I am not a German citizen :wink:
but a flamisch guy from Belgium… ( same native language as Dutch John from the Netherlands)

@ The others, in the retort system video’s you’ll see that the escaping gas gets less pressured untill a level that it stops completely, regardless the external heat you aply ( normal heat from fire )
This is the point where the charcoal is “done”, you turn the drum a few times and then can take it of for cooling down.

Hi Koen if you are showing the system around I believe it is as important to show good charcoaling methods as it is the gasifier. As an exercise you could figure out how much wood you use to process that closed retort versus the two barrel method. I believe after trying both that the two barrel method uses Much less wood and is healthier. If you are processing pyrolisis oils sure closed retort but for charcoal production only by local farmers 2 barrel wins hands down…
Best regards, David

Hi David,

I tried the 2 barrels already a few times with my papa in law,… Sure ok for domestic purposes and and,… but it take a lot more effort and time to use it and to produce the same good quality again and again…

he and his neighbor already switched to my system, with a smoke inject into the charcoal bed below the retort.
They burn below the barrel their green waste and dry leaves, twitches, branches and anything they have…
The average yield is about 30% based on dry mass input and it take less then 2 hours to cook 1 barrel to obtain 25 Kg high grade charcoal. it ignites a bit more difficult but has no smoke and no odor. It leaves no soot traces on your hands and is brittle as glas. you should hear the sound when it falls on the ground…

Second thing they like a lot, beside how fast, is there is almost zero odor when they cook charcoal now, any older system they used had this specific smell… now they don’t have that.

Anyhow, it is just a method weather to like or not. it works great and fast here, feel free to copy and or improve it.



I also have a set-up for making charcoal using the indirect method, and have marvelled at the clinking sound the “brittle-as-glass” charcoal makes. Your idea of rotating the barrel during the process is a good one. One of my small retorts fits into the afterburner of the two barrel system and uses the waste heat from the direct process to start the indirect process. I have found that all the the material used in the indirect retort needs to be cut to the same size or else the larger pieces drive smoke and tar into the smaller finished pieces, making them inferior. Attached is a photo of some really large nasty stuff that took several attempts to convert to small charcoal. I use two sizes of screens when I sort my charcoal, and then I run it through a charcoal grinder. I do not use any green material when making charcoal because it contains too much water which requires too much heat to drive it out. Besides, since we are in a severe drought, we do not have any green material. Plus that, we are not allowed to burn anything outside. The penalty is Jail Time, and a large fine! My charcoal making is “on hold”, until it rains several times, and some grass grows.