[Terrapreta] small scale charcoal making design

[jim mason]

> Here's the instructables method of feeding the smoke back into the fire:
> http://www.instructables.com/id/How-to-Make-some-Charcoal/


here is a nice design for a small scale retort type charcoal maker.
this is an improvement on the classic 55 gal drum charcoal retort as
the volitile gas out pipe is buried in a wood fire, so the smoke is
burned even before it is flammable by itself.

the smoke problem on charcoal makers is during startup, when the smoke
is mostly steam, and thus not flammable.  you need to vaporize all the
water out of the wood before the gas quality will get reasonably high
and burn.  in practice, there will nearly always be some combination
of steam and tarry pyrolysis smoke.  and the transition to an
adequately energy dense gas to burn can be long, and the smoke
produced voluminous.

a retort design like the above is much more controllable than a "fire
in the bottom and raw biomass on the top" design.  such are famously
smoky.  properly started, this design can make charcoal without nasty
smoke.

better insulation, flue gas control, and temp sensors could be added
for controlled temp char making.

jim


-- 
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jim mason
website: www.whatiamupto.com
current project: mechabolic (http://www.mechabolic.org)
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