[Terrapreta] Sustained Biochar

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Jon, so do you not believe that humans are not altering our environment
and that 'creation will cope' with anthropogenic emissions and therefore
we should all stop worrying about global warming? This is how your post
reads. If so why are you interested in this concept at all??
 
Most of the conversation on this list has come from the fear that
unburnt methane and all the rest of the 'unnatural' compounds we are
emitting are causing detrimental effects and the planet simply can't
cope, or rather cope to a degree that ensures our continued quality of
life. 
 
I certainly don't find fault in pre-columbian practices; however a lot
has happened since then, the industrial revolution for example. What was
good for them is not necessarily good for us. It is irresponsible to
continue to knowingly emit unburnt CH4, unless you don't think global
warming is of concern of course.
 
Adriana. 
 
-----Original Message-----
From: Jon C. Frank [mailto:jon.frank at aglabs.com] 
Sent: Thursday, 30 August 2007 7:47 AM
To: Terrapreta
Subject: Re: [Terrapreta] Sustained Biochar
 
The big fear over unburnt methane is overdone.  If it was so bad then
the creation of all the original terra preta soil in Latin America would
have doomed the earth to destruction.  Obviously that didn't
happen--nature coped and we are all here today.  Nature makes unburnt
methane all the time (so do you and I). So what.  Believe me creation
was designed in such a way to cope.  This is one of those "The sky is
falling" fears.
 
The creators of terra preta did not have all our advanced chemical
industry to utilize the gases the way we can now.  If we can utilize
these gases for energy great--lets use the industrial model and make
charcoal available for soil improvement.
 
On the other hand many people, especially in developing countries, do
not have access to expensive pyrolysis units but still wish to improve
their soil by making charcoal without capturing the gases.  This is also
great.  Lets also encourage the primitive model to improve the soil.
After all that's what the natives did in Latin America with great
success.
 
In whatever way people can, we should be increasing the carbon content
of soil.  The other aspect that needs to be done at the same time is
soil remineralization with rock powders.  The concept is more fully
explained at:
 
http://www.highbrixgardens.com/restore/remineralization.html
 
and
 
http://www.remineralize.org/about/context.html
 
When the soil is carbonized with charcoal/biochar and remineralized with
rock powders the soil biology greatly increases and the amount of
carbons retained in the soil dramatically increases.  In other words
carbon sequestration significantly enhanced.
 
The main goal with making charcoal by either process (industrial or
primitive) is soil restoration on a large scale.  When that happens the
soil and plants will automatically clean up the air.  The best response
will come from people getting much more nutrition in their foods and the
increase in health that results from this.
 
Jon  C. Frank
www.aglabs.com
 
-----Original Message-----
From: terrapreta-bounces at bioenergylists.org
[mailto:terrapreta-bounces at bioenergylists.org]On Behalf Of Sean K. Barry
Sent: Tuesday, August 28, 2007 11:58 PM
To: Adriana Downie; Larry Williams
Cc: Miles Tom
Subject: Re: [Terrapreta] Sustained Biochar
Hi Larry,
 
Conversion of biomass to charcoal in an "open air" retort, depending on
conditions of moisture content, pyrolysis temp, and air flow, can retain
as much as ~63% of the original carbon in the feedstock (giving ~25%
charcoal on a weight of charcoal/weight of of dry feedstock basis).
Usually under best practices, more carbon can be retained in the
charcoal, than is released in the exhaust gases.
 
The critical problem with the "open air" mound or retort is the release
of UNBURNED methane (CH4), which can be a relatively small part of the
producer gas output and contain a relatively small part of the original
biomass carbon.  It not the amount of carbon that is the problem,
though.  It is the methane (CH4) molecules that are the problem.  The
reaction of burning methane is just
 
    CH4 + 2(O2) => CO2 + 2(H2O)
 
One methane molecule is oxidized (burned) with two oxygen molecules
producing one carbon dioxide molecule, two water molecules, and heat.
So, when "burned" (or "flared" as it is called), the methane (CH4) puts
one GHG molecule (the CO2) into the atmosphere.
This CO2 molecule has no more effect on the atmosphere than any of the
other CO2 molecules that would have been released as part of the
producer gas "exhaust" output from the pyrolysis reactor.
 
Left UNBURNED though, that one methane molecule, has a much more potent
GHG effect than any single CO2 molecule.  Its GHG effect ranges from
over 100 times more potent in the first 20 years to 30 some times more
potent 100 years later, on average 62 times the potent than a CO2
molecule.
 
So, its 62 times more important to NOT release the carbon as methane
(CH4), than it is to prevent the release of carbon as CO2 molecules.  If
you retain 60% of the carbon in the charcoal and the rest goes into the
air as CO2, then you will have taken more CO2 out of the atmosphere than
would be released.  The exhaust gas CO2 would contain only 40% of the
original carbon
 
Producer gas is roughly 20%-H2, 20%-CO, 10-15%-CO2, 40%-N2, 2-3%-CH4,
plus some <<1% trace gases.  The 40% of the biomass carbon which is
released in the producer gas, goes into 3 molecules CO, CO2, and CH4, in
the ratio #CO:#CO2:#CH4 of 20:15:3.
So the methane can contain ~3-4% of the original biomass carbon, 40% x
(3/(20+15+3)) = 40 x (3/38) = ~3-4%
 
3% x 62 = 186%!,   4% x 62 = 248%
 
So, this shows that the detrimental effect of releasing unburned
methane(CH4) is 3 to 4 times (186%/60% to 248%/60%) the beneficial
effect of storing all of the charcoal that could possibly be produced
into the soil.  And, it would only reduce to being only this bad of a
thing to do after 50-75 years!
 
The lesson for anyone making a "simple" charcoal retort is to BURN the
or "Flare Off" the producer gas any way possible.
 
 
Regards,
 
SKB
 
 
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