[Terrapreta] VM composition

[Michael J. Antal, Jr.]

Dear Kevin: your question is both good, and reflects widely held
misconceptions.  A "good" charcoal with a low VM content (< 30%) will have
experienced a temperature of 500 C or more.  Tars do not survive such a
temperature.  Thus there are no tars present in a "good" charcoal.
Furthermore, the VM content of charcoal is not soluble in any common
solvent.

The VM content is simply a measure of the propensity of the material to
decompose when heated to a high temperature.  Charcoal contains various
functional groups (i.e. carboxy, carbonyl, ketone, lactone, pyranone, etc.)
that are attached to the carbonaceous backbone structure of the charcoal and
are not stable at high temperatures, decomposing to form CO2, CO, CH4, H2,
etc when heated.  These functionalities are the "VM content" of the
charcoal.

If you are interested in further details, please contact me and I can send
you two technical papers on this subject that were recently accepted for
publication in IECR.  One of these papers offers details of the actual
functional group structures that compose carbonized charcoal.

Regards, Michael.

P.S. Tars formed from biomass and cellulose are easily dissolved in
methanol, ethanol, or acetone.  We prefer to use ethanol.

-----Original Message-----
From: Kevin Chisholm [mailto:kchisholm at ca.inter.net]
Sent: Wednesday, June 06, 2007 12:27 PM
To: Michael J. Antal, Jr.
Cc: peter; terrapreta at bioenergylists.org; Tom Miles
Subject: Re: [Terrapreta] I wish to unsubscribe


Dear Mike

I reviewed the two postings you made to the Terra Preta List since its
inception, and I wonder if perhaps you comment on the following point
before you leave?

Michael J. Antal, Jr. wrote:
 > Dear friends: the VM content of cellulose is about 90% but it does not
 > dissolve in terpentine.  Need I say more?  Michael.

Would not the VM components in Charcoal most likely be tars, and
products of decomposition of cellulose, rather than cellulose?

Would tars and and the decomposition products of cellulose that are
found in charcoal be soluble in turpentine?

Do you know of any other common solvents that could be used to dissolve
tars resulting in he charcoal making process, or able to dissolve other
cellulose decomposition products that one might expect to find in
charcoal that contained volatiles?

Thanks very much.

Kevin
 >
 > Michael J. Antal, Jr.
 > Coral Industries Distinguished Professor of Renewable Energy Resources
 > Hawaii Natural Energy Institute
 > School of Ocean and Earth Science and Technology (SOEST)
 > 1680 East-West Rd., POST 109
 > University of Hawaii at Manoa
 > Honolulu, HI 96822
 >
 > Phone: 808/956-7267
 > Fax: 808/956-2336
 > http://www.hnei.hawaii.edu
 >
 >   -----Original Message-----
 >   From: terrapreta-bounces at bioenergylists.org
 > [mailto:terrapreta-bounces at bioenergylists.org]On Behalf Of Sean K. Barry
 >   Sent: Tuesday, April 24, 2007 5:01 PM
 >   To: Tom Miles; 'terrapreta'
 >   Subject: Re: [Terrapreta] Agrichar trialled in field at Wollongbar
 >
 >
 >   Hi Tom,
 >
 >   I believe that volatile matter in charcoal is all easily dissolved by
 > turpentine.  Turpentine is itself one of the liquids, which are distilled
 > from wood (a fractional distillate).  Turpentine might however be left on
 > charcoal if you were to attempt to wash VM from the char.
 >
 >   The ASTM standard D1762 measures VM% on w/w basis weight.  It does
not use
 > a solvent and the actual VM is lost in the test procedure
 >   (it evaporates).  So it will only get at the weight of the VM or VM% of
 > the charcoal on a w/w basis.
 >
 >   Maybe a procedure could be developed to wash VM from charcoal with
 > turpentine, measure the weight of the VM which was washed out, and
actually
 > have the VM (in solution with the turpentine).
 >
 >   1) Dry a pulverized charcoal sample at 105 degrees C for some hours (or
 > until it no longer loses weight).
 >   2) Add a measured (weight) amount of turpentine to the charcoal (for a
 > wash) in a sealed container.
 >   3) Weigh the wash solution with the charcoal together after some
period of
 > washing agitation.
 >   4) Pour out the wash solution (containing turpentine and VM)
 >   5) Drive off the turpentine left on the charcoal by bringing its
 > temperature up to the boiling temperature of turpentine for some minutes.
 >   6) Weigh the cleaned (of VM) and dried (of turpentine) charcoal.
 >   7) The weight of the VM should then be;
 >       weight of wash solution and charcoal (step 3) - weight of
cleaned and
 > dried charcoal (step 6) - weight of turpentine (step 2)
 >   8) The Volatile Matter itself will be in solution with the
turpentine in
 > the post wash solution.
 >
 >   If the procedure was tried on duplicate samples, one with ASTM
D1762 and
 > one with the test procedure I proposed, then the resulting %VM
numbers could
 > be compared.  If they match closely, then I think it would be safe to say
 > that the total measurable VM can be "washed" from the charcoal sample by
 > using the procedure.
 >
 >   I think this could work.  Then the actual VM could be further analyzed.
 > This presumes that the turpentine does no chemically react with the VM
 > (other than to dissolve it).  I'd welcome any comments from anyone
who might
 > think it won't work for any reason.
 >
 >   Regards,
 >
 >   SKB
 >     ----- Original Message -----
 >     From: Tom Miles
 >     To: still.thinking at computare.org ; 'Sean K. Barry' ; 'terrapreta' ;
 > 'Michael Bailes'
 >     Sent: Tuesday, April 24, 2007 6:53 PM
 >     Subject: Spam: RE: [Terrapreta] Agrichar trialled in field at
Wollongbar
 >
 >
 >     Duane, Sean, Michael,
 >
 >
 >
 >     These are good references. The ash composition of the woods, grasses,
 > pulping residues, sludge, etc. will carry varying quantities of
nutrients to
 > the degree that they are retained in the char. Through studies like
these we
 > know more now about the volatility of the inorganics (K, S, Cl) during
 > pyrolysis, gasification and combustion.
 >
 >
 >
 >     I was referring primarily to measuring the volatile matter (VM)
that is
 > apparently available to the organisms which is what Steiner must have
been
 > referring to as the bio oils that are retained in the char. If a char has
 > 10%,  20% or 40% VM is it all available to the organisms or some portion?
 > How do we measure that? Is the VM that is available soluble in a dilute
 > acid?
 >
 >
 >
 >     Tom
 >
 >
 >
 >
 >
 >
 >
 >     From: terrapreta-bounces at bioenergylists.org
 > [mailto:terrapreta-bounces at bioenergylists.org] On Behalf Of Duane
Pendergast
 >     Sent: Tuesday, April 24, 2007 7:04 AM
 >     To: 'Sean K. Barry'; 'terrapreta'; 'Michael Bailes'
 >     Subject: Re: [Terrapreta] Agrichar trialled in field at Wollongbar
 >
 >
 >
 >     Sean, Michael
 >
 >
 >
 >     This work from Denmark seems relevant under this topic. A site
search on
 > the authors names indicates it has not been discussed here.
 >
 >
 >
 >
 >
http://pubs.acs.org/cgi-bin/abstract.cgi/enfuem/2005/19/i04/abs/ef049739a.ht
 > ml
 >
 >
 >
 >     Duane
 >