last up date 14/Feb/2009
How to make a charcoal-making kiln

                                 Copyright 2006 by Masato Iwasaki

This information is free to the public for construction and use by individuals.
Commercial use is prohibited.


Development of the charcoal-making kiln for soil improvement took eight years.
The ability to make charcoal at high temperature is the special feature of this charcoal-making kiln.
Charcoal can be made at low temperature, too.
Dried bamboo, corn, and sunflower can be carbonized within three hours.
Hard charcoal, which usually requires twenty hours to make, can be made within five hours.
Hard charcoal is good for improving soil quality.
The charcoal-making kiln can make both black charcoal and white charcoal.

Chips of chaff, corn cobs, stalks, and sunflower stems are mixed to dry soil in a 50-50
ratio (50% soil, 50% biomass), and used to surround and insulate the kiln.

The foundation is made from bricks and stones. This is covered with 20 cm thickness of soil for insulation.
Bricks are piled up to make 60 cm high walls around the kiln. The walls form a rectangle around the kiln.
A space of 15-20 cm is necessary between the brick walls and the front, sides, and back of the kiln, and
also the chimney. {Soil-biomass mixture is put in this space to insulate the kiln.}

After the kiln is set in place, the chimney is installed. An L-shaped bent pipe is attached to the adapter on
the kiln, and the chimney is attached to this bent pipe.
For the chimney, although stainless steel pipe is good, an earthen pipe can be used instead.
An earthen pipe can be made from clay, attached to the kiln, and fired with the heat of the kiln.
The earthen pipe made in this way will have many cracks, but it will be satisfactory for the chimney.
The height of the earthen pipe should be about 2 m.
To attain internal temperature of more than 900 degrees, 4 m pipe is necessary.

Then, soil is put in the space between the brick walls and kiln for insulation, and the kiln is complete.
The kiln will have a scorched smell at first.

1. Preparation of the material. 2.Preparation of the material.
3. Scribe line for cutting the carbonization furnace. 4.cutting use disk-cuttter
5. Scribe lines for the covers at 120 degree sections. 6. Drum can is cut into two parts: left side becomes the firewood combustion section; right side is for making 3 covers.
7. 3 cm slits are cut and bent inward. 8. Scribe lines for firewood opening to firewood chamber.
9. 10. Prepare firewood opening.
11. 12. Firewood opening is cut..
13. Scribe lines for openings on carbonization furnace.
side 50mm center 80mm
14. Cut openings on carbonization furnace.
15. Scribe circle for exhaust hole.
D=90mm
16. Cutting the exhaust hole.
D=100mm sharpen it in a circle neatly
17. Scribe lines for high temperature air passageway. 18. Cut high temperature air passageway.
19. Angle iron is welded. 3×30×3t 20. Angle iron is welded on sides to prevent drum
can from collapsing at high temperatures.
21. Weld together the firewood chamber and carbonization furnace. 22. Installation of the exhaust adapter
23. Grate is welded. 24. The completed charcoal-making kiln.
Reinforcement Charcoal making kiln center less(use 4 drumcan type)
A.Reinforcement type front B.Reinforcement type inner side
C.Reinforcement type upper D.Reinforcement type rear
E.Reinforcement type cover F.Reinforcement type center 8φiron pole
G.Alminium cock type is cover by steel seat H.New type use 2 set. 70mm-60mm-60mm-50mm t=3mm
I.Canned collection of the pyroligneous acid
from smoke.
J.A real state.
K.Cut openings on carbonization furnace.full open L.cover center angle
M.cover side angle N.new type front separate
O.Perform internal reinforcement O.Attach a cover to the front

If charcoal kiln temperture over 1000℃ must add Reinforcement type.

How to make full-scale charcoal.
Time to burn the charcoal becomes more than 20 hours from five hours.
Equal to or less than 180 degrees Celsius and keep temperature of the carbonization department more than 15 hours.
The combustion department puts a large quantity of firewood and puts on fire.
If total firewood gets fire, make an entrance less than 2cm corner and perform temperature control.
If 15-20 hours passed , perform normal charcoal making.

Making charcoal kiln if the charcoal was, thank you a report of doneness.
Email:((charcoalkiln@gmail.com))
    NUll (( )) and underline.


〔return to main page〕