[Stoves] TLUD and biochar production

Tue May 7 07:58:16 CDT 2013

I have to agree with Josh and Ron, and wonder which TLUD stove Frank
is using for cooking meals.  At the end of a cooking session, the
charcoal in the bottom of my stoves is glowing brilliant red with
small purple flames.  If I extinguish the char in a bucket of water,
there are very few floating pieces of charcoal (these are easily
skimmed off and dried separately for future use in another cooking
session).  During a week's time, the remaining charcoal is washed and
screened over a compost pile, and then dried in the sun.  This is high
quality charcoal, and can be used to run a generator, log splitter, or
other 4 cycle engine.  For the last two years, I have been screening
charcoal with 1/4" mesh screen, and adding these screenings to compost
piles that I turn with the front end loader of a diesel tractor.  This
year, I have begun a two part screening process for the char.  The
material that falls through the 1/4" screen is retained, and subject
to another screening with 1/8" hardware cloth screen.  The result are
pieces of charcoal less than 1/4" and greater than 1/8".  When mixed
into the compost, it makes a fantastic potting soil, and our garden
has never been as beautiful as it is today.  My neighbors are begging
for compost!  We harvested 3" onions, arugula, spinach, and asparagus
yesterday.  The tomatoes are 3" in diameter, but still green.  We are
using no commercial fertilizer.  My neighbor is buying bags of Miracle
Grow fertilizer, but our garden is out performing her garden.  I
should add that I cannot get enough of this stuff, and have collected
dead trees and limbs to process 120 fifty-five gallons of biomass into
charcoal.  (I keep a record of each burn.)  If you watch Josh's video,
you will see that he is processing limbs of wood all cut to a uniform
size, and even some of the larger diameter pieces break easily, and
have no trace of raw wood in the center.  On the other hand, I have
been processing some wood from dry creek-beds that is too dirty to
saw.  I throw six inch dead logs into the barrel, surrounded by
smaller wood, but packed solid.  When the bottom holes "illuminate", I
close off all air, and a day to two later, dump out the contents of
the barrel.  The larger logs are called "brands", and I carefully pick
them out for the next barrel (after another run, they are turned into
walnut sized pieces of charcoal).  This total operation creates no
smoke, similar to what Josh is showing for uniform sizes of wood.  If
logs are present, there is a bit of smoke when the barrel is being
sealed.  The end result needs careful inspection and screening because
the charcoal is often not a good as the charcoal made in the TLUD
stoves.  Rejected charcoal can, and is, finished (as fuel) in a
cooking or water heating stove.  Large brands go into the top of the
next 55 gal drum to be processed into charcoal.

On Mon, May 6, 2013 at 8:41 PM,  <rongretlarson at comcast.net> wrote:
> Frank, Josh,  and list - see below
>
>    Most of this was written before lunch and so only a bit of response below
> to Josh,  who also answered Frank.   Not exactly relevant, but I went down
> to the Colorado House (Ag committee)  to support SB 13-273, which puts a
> little bit more state emphasis on removing beetle kill. (Minimize fire
> hazard)  Passed the second chamber committee with only 1 "Nay" vote, so is
> sure of getting through the remainder.  The only reason for going was to get
> the word "biochar" on the table.  The Committee chair (Fischer - who knows
> biochar) helped by asking a question.
>
> More below, trying not to duplicate Josh
>
> ________________________________
> From: "Frank Shields" <frank at compostlab.com>
> To: "Discussion of biomass cooking stoves" <stoves at lists.bioenergylists.org>
> Sent: Monday, May 6, 2013 10:52:13 AM
> Subject: [Stoves] TLUD and biochar production
>
>
> Dear Stovers,
>
> It seems that a TLUD would make poor quality biochar.
>     [RWL1:  This is a strong statement that requires more proof than you are
> giving.  My contrary belief (based on what  I read about improved ag
> production from char made in TLUDs) is that  such char is very good.  The
> reason is that such char is often measured to be around 600 C - near the
> supposed sweet spot.
>
>
> There are only two hot
> spots. One is the flame front and the second the flame heating the pot.
>     [RWL2:   The most important hot spot is a third one - at the (moving)
> pyrolysis front.]
>
>
> As
> the flame front migrates down through new biomass volatiles come off and hit
> cooler conditions above in the left over char where I would think
> condensation of organics would occur.
>     [RWL3:  You should be using the term "pyrolysis front".  The only
> "flame" ever traveling through the char is after the pyrolysis front reaches
> the bottom of the fuel bed (and that is when to stop).  The "cooler" char
> above the pyrolyss front is still very hot and not much condensation is
> occurring  - as I understand it.   In fact there may be more cracking in
> this hot char area.  Very little CO2 gets through  (which is ideal, as we
> want the CO that comes about because the char is hot enough).
>
>       Josh Kearns has an earler response note on this, which I endorse.  But
> it would be ideal to have someone report in detail.  Plots I have seen of
> char temperature are quite constant over time, once the pyrolysis front has
> passed.  There are always tars left, but as Josh sad, those are useful.  The
> char-making stove char hasn't received any bad press that I am aware of.
> There is a lot of good press.
>
> This is good as a cleaner gas goes up
> to the secondary air to combust and heat the pot. But the char is left with
> tars. This could be better for used as charcoal for other cooking but would
> make very poor biochar for the garden - if this is what happens.
>
>      [RWL4:  So my "If" response is that "this is NOT what happens".  Anyone
> have contradictory evidence?    Ron]
>
>
> Regards
>
> Frank
>
>
> Thanks
>
> Frank Shields
>
> BioChar Division
> Control Laboratories, Inc.
> 42 Hangar Way
> Watsonville, CE  95076
>
> (831) 724-5422 tel
> (81) 724-3188 fax
> frank at biocharlab.com
> www.controllabs.com
>
>
>
>
>
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-- 
Ray  Menke