Dear Tom R. & list,
A short selection of biochar research being carried out in Oz.
Unfortunately up till now this has been dominated by low temperature
pyrolysis proponents who often wear two hats, as university researchers
and private company officers promoting their own technology. Nonetheless
there has been some good work.
http://www.csiro.au/science/Biochar-Overview
http://www.csiro.au/en/Outcomes/Environment/Australian-Landscapes/Biochar-Factsheet.aspx
http://www.publish.csiro.au/paper/SR11316.htm
http://www.csiro.au/files/files/pxqb.pdf
http://www.dpi.nsw.gov.au/research/topics/biochar
http://www.iie.org/Programs/Alcoa-Foundation-Advancing-Sustainability-Research/Biochar-and-Energy-from-Trees
More recently our own work with gasifier chars has started to be
recognised and there is now a chance our chars will make it into formal
research programs (we have been trying for some time). The recent bomb
shell dropped by NSW EPA at a Federal Biochar Methodology Development
meeting in Canberra that Biochar is classed as a "waste" and therefore
subject to EPA approval and requiring an exemption for land application
has sent many of the researchers and pyrolysis companies into a spin.
This ruling presents few issues for gasifier based biochar plants but
can be very problematic for low temp pyrolysis retorts, starting with
management of air emissions but extending to what possible toxic
components might exist in the resulting chars.
Gasifier chars generally are higher in fixed carbon (lower volatiles)
than low temp pyrolysis chars, they have higher absorption rates
(pyrolysis chars have higher adsorption). Gasifier chars have lower
alkalinity than P.chars. so can still be usefully applied to alkaline
soils. Typically gasifier chars will have much higher iodine numbers
compared to other chars so may be more suitable for cleanup of
contaminated sites.
We believe gasifier chars have some natural values that boost the
overall gasification picture, use of chars as a soil amendment is only
one of these, water treatment (for potable water) and sewerage
management are some of these (particularly in areas such as Haiti) but
there are also others including odor control in compost operations,
metallurgy, mining etc.
Our experience has been that often you will find plenty of waste biomass
but only limited need for heat & power on a given site. Finding another
product then other than clean gas is important, retaining a significant
proportion of the biomass energy in the form of carbon then opens up a
wide range of opportunities.
Cheers,
Peter
Real Power Systems
----------------------------------------------------------------------
Message: 1
Date: Tue, 25 Dec 2012 22:45:00 -0500
From: Tom Reed <[email protected]>
To: Discussion of biomass pyrolysis and gasification
<[email protected]>
Subject: Re: [Gasification] [biochar] ICM gasifier project comes to a
close
Message-ID: <[email protected]>
Content-Type: text/plain; charset="utf-8"
Dear Ron
I have been following your Emails with Bert with interest, having been involved
in many failed gasification projects, and a few that have succeeded (Community
Power Corporation in Littleton).
<><><>
Biochar adds a new dimension to practical gasification projects. If there was
a strong positive demand from agriculture for Biochar, we could be home free,
but that has yet to be established and may not occur in our lifetimes.
There are still unanswered questions about Biochar and I hope to get answers
this Spring.
<><><>
The easiest method of making Biochar is to take a dense pyramidal pile of dry
wood ( for instance chopped up tree brush after a tree is felled) and light it
on top. As charcoal forms in the first layer, it ignites the cellulose
volatiles coming up for the second layer.... and eventually the whole pile (or
stove or can) is full of charcoal.
This could be called "AutoPyrolysis", since it is the heat from burning the
cellulose in each chip that converts the lignin in the chip to charcoal. And it also
leaves a clean, combustible gas as a by product which should be converted to electric
power.
I have measured the charcoal production rate for wood chips at various
conversion rates and moisture contents. It can be as high as 25% with bone dry
chips, but 20% is a safe number for 15% MC chips.
<><><>
This charcoal is low in volatiles, since the need for a flame limits the lowest
temperature practical to about 500C. Is that good or bad?
What is the most effective size for charcoal in soil? Wood chips make a convenient
size, but the product is friable and possibly 1/4 " or smaller could be better
for growing plants.
<><><>
I hope to test a number of these questions this spring.
Your pal, Tom Reed
(I wish we could play Racketball 1-2 times a week. I'm rusting out!)
Thomas B Reed
280 Hardwick Rd
Barre, MA 01005
508 353 7841
------------------------------
Message: 4
Date: Wed, 26 Dec 2012 11:16:55 -0500
From: Thomas Reed <[email protected]>
To: Discussion of biomass pyrolysis and gasification
<[email protected]>
Cc: Discussion of biomass pyrolysis and gasification
<[email protected]>
Subject: Re: [Gasification] Gasification Digest, Vol 28, Issue 7
Message-ID: <[email protected]>
Content-Type: text/plain; charset="utf-8"
Dear Tom Miles and all
Biochar has changed the options with wood gasification, but there are several
questions that need to be answered.
O. Using Toplit Updraft gasification, you have the option of keeping 20% charcoal as a
by-product. In this case, the heat for pyrolysis is more than supplied by the volatile
products of pyrolyising the cellulose and converting the lignin to charcoal.
Temperatures in the autopyrolysis bed range from 500-700C, higher than those generating
"cowboy" charcoal.
So is this charcoal superior to Cowboy?
O Since wood is typically 50% carbon, and charcoal yield for TLUD gasification
is 20%, you will put one CO2 into the atmosphere for every Carbon sequestered
as charcoal. But that's better than letting all the C in the wood turn to CO2
or methane as would otherwise happen.
Comments?
Tom Reed
Thomas B Reed
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