Big Size Charcoal Retort Kiln – Comercial Model Charcoal Kiln

Comercial charcoal Kiln big charcoal Kiln

Big Size Charcoal Retort Kiln – Comercial Model Charcoal Kiln

This is a Comercial Model Charcoal Kiln . Being sale at too expesive price . but i think you guy can make yourself one charcoal kiln like this way cheaper .

The Pressvess retort – A big double charcoal burner opens up new markets for using wood waste

Though the kilns were pioneered by charcoal producers, Four Seasons Fuel from Suss-ex, they need high throughput to justify the investment. Which is why Forest Research are studying their use for filtering and the Glasshouse Project from West Midlands may be able to use such a system as part of their centre for people with learning difficulties, to provide work experience with such a kiln

bottom of this post have a video clips will show everything inside the kiln and the way it designed.

Charcoal Retorts

Double retort made with 10mm steel body, (2 units each of 1mtr x 2mtr x 15mm)Boiler plate charge drums

Total output charcoal of 350 – 400kg per burn pending on wood species & seasoning

The doors are made with 500mm of ceramic blanket sandwich in two plates of 4mm steel, which help heat retention.

The gases exhaust on the doors. When the gases are exposed and rise they pass through the vent in the door travel down in the fire box exhaust system this is made out from 8m s/steel tube with 4 exhaust ports which are pass though the fire bricks into the fire box then the gases reunite and rise up through the spaced fire bricks around the cylinders down to the rear vents and then retort again.

The entire inner part of the retort is lined with 500 mm of ceramic blanket, which is important to keep the heat retorting around the cylinders.

The burn time is 8 to 10 hours depending on the grade of wood you are using (8 to 10 hours is time based on OAK, ASH, BEECH or HORNBEAM). This is a lot less than with round kilns.


More Information on Charcoal Retorts

We use these same version of these retorts for charcoal production on our site. We use the wood’s natural gases to reheat the retorts. By using the wood””s natural gases to reheat the retorts the retorts offer significant advantages. The retorts systems offer a higher productivity and more efficient way of scaling up production than operating a larger number of small round kilns. Our retorts offer possibilities of more efficient use of raw materials. (i.e. 4 x1 ratio) is a normal for these retorts, (compared with the normal steel round kilns at 7 x 1 ratio)

Big Size Charcoal Retort Kiln 2 Big Size Charcoal Retort Kiln burning 2

Big Size Charcoal Retort Kiln burning
Big Size Charcoal Retort Kiln burning
Big Size Charcoal Retort Kiln design
Big Size Charcoal Retort Kiln design

Big Size Charcoal Retort Kiln open Big Size Charcoal Retort Kiln vents Big Size Charcoal Retort Kiln


Loading (charging) time for the retorts is approximately 45 mins (depending on how you stack the charge). We stack ours in an unorthodox manor. We stack the front of the kiln, then throw the wood at the back placing small at the bottom followed by medium at half way then large wood at the top.

Remember to keep the drains clear from the wood to avoid build up water from the wood (Such a build up will add to your burning time)

When all charges are full close the doors and making sure the top door vents are sealed with sand. Remember the charge must be air tight when the gases come in. When starting just leave the drain hole cover off. So when you start a burn you will see water & gases come though the bottom drain hole. Wait until the gases are dense then screw the drain hole cap on. Keep feeding the firebox, till the gases hit 300 degrees C to 38O degrees C (depending on what wood you are burning).

The Cooking Time
Cooking times of as little as 8 to 10 hours can be achieved by preburning. (Cooking times without preburning takes about 6 hours longer)


Reburning is very simple. After loading the charge all you have to do is light as before, keeping it going till the wood menthol starts to come though leave it till the next day. (You could put charcoal fines in the firebox, this will keep the temperature this will slow burn over night in the morning just rack the firebox this will reunite and feed as normal. Once the gases are reducing this means that the cooking is over this will take time to learn.

Once the gases reduce you can either take the door vents caps off and wait till the temperatures drop to 350 degrees C and then take the vent at the rear out then leave it so it cools quicker to unload next day. (remember to replace the door vent caps, sand and seal to prevent air entering the charge) or you can just take the rear vent out and leave it.

NOTE: When you open the door and it feels too hot to unload close the doors making it air tight leave to cool longer.

When you open the doors and you see red embers this means that the doors where not airtight or the top vents where not sealed after venting off. Poor water over the red-hot coals, wait till water has exited, close the doors and wait to cool. The water will evaporate and dry the charcoal (just like they do and earth burn).

Cooling Time
On your first bum cooling time will take around 16 hours (due to the menture contents of preheated metal and sand base these need to be dry). After each burn your time should reduce and start to level out.
If you work in a controlled areas smoke can be trouble. With a retort the wood you use in the firebox can control smoke. Treated timber such as pellets and tanning woods will smoke but if you use untreated soft wood there will be less smoke. On average the reduction of pollution with a retort is 75% less smoke than round steel kilns.

Once the gases come in around 300 to 380 degrees C or less there will be less and less smoke. Using a retort is a real advantage for reduction of air-pollution.

Venting Control
The retorts can be easily controlled by Venting Control. There are vents at the rear these are to control the burn which on each charge (For example, if the left change is burning faster than the right you would open the right vent 2 or 3 inches and close the left 2 or 3 inches. This will draw the heat to the right charge).
Venting Off
For rapid reduction control in temperature. Vents are located on the doors you would only use these if the temperature in one of the charges exceeds 604 degrees C this is what we call a safe temperature. To Vent Off lift off the top and light the gases. This will reduce the temperature. Try to maintain the temperature at around 590 to 600 degrees C for as long as possible till the gases in the Firebox is not as strong as they were.

Finishing Off
Once the gases are reducing this means that the cooking is over. (This will take time to learn!)

When the gases have reduced you can either:-

When the temperatures are around 40 to 45 degrees C it is safe to open the doors. Once open you will see how much the wood has reduced. If you see a few brown ends (wood that has not been cooked long ) you will know that next time you need to keep the temperatures more constant and which wood to put in for quicker burning (oak & hornbeam will take longer than ash or beech, birch will be the quickest wood to burn).

  1. Take the door vents caps off. Light the door vents each side the retort; wait till the temperatures drop to 354 degrees C (remember to sand and seal the door vents) Then remove the rear chimney vents and leave to cools quicker. Next day unload.
  2. Take the rear vent out and leave it. Cooling time will be long


 Build Specification


Comercial charcoal Kiln
big charcoal Kiln

The round kilns are Made from mild steel of various thicknesses thought out
1 x Ring – 5mm, 8”” diameter x 1 meter high (Top flange – 5mm, Bottom Flange – 10mm)

1 x Lid – 2mm

8 x Ports – 5mm

4 x Chimneys ( 100mm diam, 6”” long tubing – 2mm)

Here is the video clips will show everything inside the kiln



  1. Thank you a lot for sharing this with all of us you actually understand what you’re talking approximately!
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  2. Very interesting, thanks for sharing. The remainder of the process, screening, bagging etc is another aspect that i am looking to understand.

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