[Gasification] [biochar] ICM gasifier project comes to a close

Wed Dec 26 22:13:21 CST 2012

Peter,

There are probably more gasifier chars used as biochar than most people
realize. I agree that gasification chars seem to be very useful for use as
biochar. I haven't really seen enough thorough analysis of gasifier chars to
be able to generalize on their characteristics as distinct from pyrolysis
chars.  I do question your statement about gasifier chars being less
alkaline than pyrolysis chars. Given the same feedstock a gasifier char will
have higher ash, higher pH, and likely higher alkalinity than a pyrolysis
char. 

Tom   

-----Original Message-----
From: Gasification [mailto:gasification-bounces at lists.bioenergylists.org] On
Behalf Of Peter & Kerry Davies
Sent: Wednesday, December 26, 2012 6:03 PM
To: gasification at lists.bioenergylists.org
Subject: Re: [Gasification] [biochar] ICM gasifier project comes to a close

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-Fa
ctsheet.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-Resear
ch/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 <tombreed2010 at gmail.com>
To: Discussion of biomass pyrolysis and gasification
	<gasification at lists.bioenergylists.org>
Subject: Re: [Gasification] [biochar] ICM gasifier project comes to a
	close
Message-ID: <DC601DB8-2CCB-4EAB-AD70-275A0B3A3DED at gmail.com>
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 <tombreed2010 at gmail.com>
To: Discussion of biomass pyrolysis and gasification
	<gasification at lists.bioenergylists.org>
Cc: Discussion of biomass pyrolysis and gasification
	<gasification at lists.bioenergylists.org>
Subject: Re: [Gasification] Gasification Digest, Vol 28, Issue 7
Message-ID: <7E820F35-4E9C-4B0A-8EEF-1928E0A8573F at gmail.com>
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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