Heating a kiln and producing biochar in the process

[Acroberson]

Hey Long time lurker, first time poster.  So I live in Texas and have a very small solar kiln. Wood dries here pretty quick. I do quite a bit of tree trimming and building cedar fences, so I come across wood but I also need to buy wood. I'm in the early process of building a much larger kiln. I was wondering if anyone here burns swarf or scrap wood in a low to no oxygen environment to create biochar (basically charcoal) as a process to heat their kiln. If you don't know what biochar is you should look it up.  It's the building block of humus (not the dip) and is in high demand. I have seen several occasions where the heat is dumped into a water tank which is then circulated under greenhouses in order to heat them. It seems to me if you could incorporate burning scrap to heat your kiln and make biochar in the process it would be a win-win.  Look what activated biochar sells for on any website and you will understand what I'm talking about. I just don't have the time to sit down and try to work out all the math. I know this can be done. If someone is doing this on a small scale and could contact me I would appreciate it.  Sorry for the long first post but Ive posted similar questions in other forums and haven't received any good answers.

[Don P]

There is some interest here, I've done a bit of research and made some. Use dry feedstock or you will consume a lot of wood drying the rest. The best fuel is the charcoal, so you are stopping short of using the prime material for heating. Charcoal production is typically dirty, polluting, nasty work. There are ways to do it better but I'm not sharp enough to see how to make it work small scale. I'd sure like to hear about it if you see a way to crack that nut. This should be a paper on different production methods.
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[GeneWengert-WoodDoc]

Although you can char wood at 200 F, it takes years.  So, we need to chat it at higher temperatures.  When we first heat the wood to 450 to 1000 F, the heating stops at 212 F in an area until the water is gone.  The. Heating continues, releasing various flammable gases, which ignite and burn, , or if cooled without burning form creosote. After gasification, all that is left is carbon. The carbon that remains does not burn without oxygen.  Further, charcoal burns at around 1100 F.

What this means is that the chamber for making charcoal needs to have a fire started, needs to have a pressure relief vent, needs to be so,tight that oxygen cannot get in once burning starts, must have no fire when the door is finally opened.  Oftentimes, charcoal,is mixed with corn starch or,other binder, and maybe a little wax and compressed into briquettes.