Re: Biocahr in field. #technology #flamecap

Frank Strie

Yes that is true Paul Anderson. Flame curtain kilns, especially the kind of deep cone kilns we designed in Tassie with a few internal  features missing by most other flame curtain kilns( small to very BIG ones)  I am aware of.
We also have an optional extra on our KON-TIKI-TAS  Standard and KTT Stretch Cone Kiln models that we trade and ship to customers around Tasmania and mainland Australia these days.
Even after  6 years we keep modifying and improving our kilns by observation and by actually operating these units with all sorts of woody materials from slashed Blackberry shrubs , Grape Vines, Hazelnut grove material, and fruit tree branches and Olive grove material…. The post carbonisation  process is also interesting and the carbon cascade issues.
It helps to live on the land and to grow things ourselves so we have a vertically integrated  business situation involving the whole family clan incl. livestock and poultry …
We make, use, plant, grow consume, eat and drink the things  that emerge on the properties here in Tassie ourselves and we can sell what we have surplus in the process, ornamental things, veggies, fruits and plants, kilns and technologies and consultation and presentations, the process continues  now in my 14th year of intensive work with Terra Preta Developments…
3 generations in our family clan live it!!

from an amazing spring in Tassie, the sun is shining after good rain on Friday
(and Tassie is by now without CORONA for about 120 days or so, no strikes or protests in our streets)

PS: Now I am going out to plant potatoes and harvest fresh , juicy and tender Asparagus spears for dinner tonight.

From: <> On Behalf Of Paul S Anderson
Sent: Sunday, September 27, 2020 12:43 PM
Cc: Anderson, Paul <psanders@...>
Subject: Re: [Biochar] Biocahr in field.


Kelpie and all,


The statement is not correct:    “All of these kilns are Flame Cap Kilns and they work essentially as continuously fed updraft gasifiers (no bottom air).”


Flame cap deserves recognition for being something useful with distinctive flows of air.   I am a strong advocate for flame cap devices,  which I refer to as cavity kilns, which can be with an open top or with a (mostly) covered top.   


Flame cap technology is distinct from what are the established “gasifier” technologies.   An updraft gasifier is defined as having air entering at the bottom.   Let’s not put flame cap and gasifiers in the same category. 




Doc / Dr TLUD / Paul S. Anderson, PhD --- Website:

         Email:  psanders@...       Skype:   paultlud

         Phone:  Office: 309-452-7072    Mobile & WhatsApp: 309-531-4434

Exec. Dir. of Juntos Energy Solutions NFP    Go to: 

Inventor of RoCC kilns for biochar and energy:  See

Author of “A Capitalist Carol” (free digital copies at

         with pages 88 – 94 about solving the world crisis for clean cookstoves.


From: <> On Behalf Of Kelpie Wilson via
Sent: Saturday, September 26, 2020 8:26 PM
Subject: Re: [Biochar] Biocahr in field.


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Ken Carloni and Darren McAvoy of Utah State are both working on Big Box biochar kiln designs. I am focussing more on the smaller hand-fed kilns - Oregon Kiln and my new Ring of Fire kiln. All of these kilns are Flame Cap Kilns and they work essentially as continuously fed updraft gasifiers (no bottom air). 


All three of us have converged on some basic design principles that include: 


1. The right shapes to minimize surface to volume ratio so you don't lose heat out the sides. You don't count the base that is insulated by the ground, or the top where the flame cap is. Cones and troughs are not the best for this. Cylinders and rectangles are better. Sloping sides are handy for stacking kilns (like Oregon kiln) but not needed for operation.


2. Not too tall so you have the option of hand loading. Machines can actually be slow and inefficient and may be best for delivering loads of feedstock to the hand crew.


3. A heat shield makes a big difference. Holds in more heat for faster processing. It also helps a lot to protect workers from radiant heat that causes fatigue and dehydration. And it provides pre-heated air through the gap that contributes to the counterflow fluid dynamics that keep smoke in the hot zone longer for cleaner combustion. 


4.Quenching can be with water or with a snuffer lid. If using a snuffer lid, bigger kilns will take more than a day to cool down, so your kiln will be out of action for that period. If using water, you can either flood and stir, or dump, spread and spray. Unburned brands should be removed and set aside for the next burn, or left on the ground for the microbes to eat. 


5. Feedstock considerations #1: Size. Most important is uniform size. Start with small brush and let it burn till it chars and falls to the bottom in a layer of glowing coals. Then start adding bigger material if you have it. The flame front will move up and the small brush char you made will be protected from air so it does not burn up. Bigger logs (4 to 6 inches diameter) evolve more gas and heat and can char all at the same time in a stack of uniform material. If you mix smaller stuff it will just burn up to ash before big stuff is charred.This is why the Air Burner demos have shown poor efficiency. An Air Burner is just a flame cap kiln with an active counterflow provided by a blower. It is meant for incineration and people are used to throwing giant logs, stumps and everything in there to burn to ash for waste disposal. This will not make char. The Air Burner needs to be operated like a flame cap kiln. You don't even really need the blower if you do it right. And don't try to char big stumps and giant logs. It won't work and you will get mostly ash. 


6. Feedstock considerations #2: Moisture. Dry is best, but green is good. Ken and I are starting to char green brush. Green brush actually has more fuel value than dry brush because it still has volatiles. It also has water, so that takes more heat to evaporate, so it's a trade-off.  If the green brush is small enough and you have dry material to get started, you can add green once you have a bed of hot coals and it chars just fine. This is important for labor saving so you don't have to do more than one entry to the site. You can cut, drag and char all on the same day. It is probably also making a somewhat lower temperature char, but there is no data yet.


7. It would be really great to get some funding to test emissions, char conversion efficiencies, char characteristics, and field operations and logistics of different designs. I am sure we can make more improvements if we have a little support beyond our own pocket books. 




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