We have seen Shou Sugi Ban discussed here on Permies before.
Recently I have been investigating the
Iwasaki-type high-speed charcoal kiln .
It makes high quality white charcoal quickly, and can be made with hand tools almost anywhere in the world.
It also produces and collects
wood vinegar and at your option tar.
This is actually the clearest most concise explanation I've found.
It consists of a conventional steel box
wood stove vented into a steel "bell".
The bell is essentially a black oven for the wood.
The exist temperature of the exhaust is monitored, and during a particular temperature band, wood vinegar is collected via a simple condenser.
The steam before that point is allowed to escape, and the exhaust after that point is also.
The later exhaust is filled with tars, and could be burned, or collected.
The most obvious way to improve this device is to make the fire more efficient, but substituting a
rocket stove for the conventional flame.
But currently my interest is this:
How far could one take the process of pyrolysis before we lose any useful structural qualities?
This paper
PARTIAL PYROLYSIS of WOOD concludes that :
"A piece of dried wood cut with its long dimension parallel
to the grain of the wood will not change in length materially,
but it will shrink quite uniformly in cross section.
The modified wood from the treatment at 220-240° C. will be stronger
and have a higher apparent elastic limit but will be somewhat
more brittle than the original wood. It will have smaller
volume changes with changes in humidity. The modified
wood is brittle
enough to be crushed rather readily to yield
a wood flour stable at 240° C., which may be incorporated
into molding compounds."
So, getting to my point, what if used these extreme heat treatments on large logs, and applied their own tars back onto them?
Using tar, from any source, is probably out of the question for many here.
Off the top of my head, I can't disagree.
We burn them in when we burn wood, but collecting them in one place is different.
Not a lot of oils
The destruction of of the woods structure may prove to be much.
And that paper was published March, 1943, so...
But if it worked well, wouldn't that be neat?
Right now I'm imagining a very insulated tunnel of steel drums with a batch
rocket stove or Tlud venting into the middle.
A set of rails and a low sledge or cart, all steel ,would guide loads down a slight incline.
In one end and out the other, at least 4 drums long.
Large loads cranked along with winches, chocked into place and treated for hours?
Longer?
The insides of a log need treatment, that will take longer than a load of 2x4s.
A chimney near the exit, down low, maybe into a tee.
Wrap it in rockwool not for insulation , rather it could hold the
water that the chimney is cooled it with.
Probably needs a bypass from up higher on the bell.
Collect the wood vinegar, and burn the tar.
Douse the
feed stock when your temperature probe gets to 240 degrees C.
Foundation piers,
fence posts, sculpture, artist charcoal, BBQ charcoal ,
biochar, roast pigs, or goats...
Worst case scenario, you have a giant oven.
Enough sky bluing, I would love to hear your thoughts on this madness!
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