[Terrapreta] Farm Produced Biochar

Fri Aug 17 14:46:54 EDT 2007

Hi all,

Sorry for my poor knowledge in chemical processes, but with hydrothermal
carbonization, I don't understand how you eventually obtain biochar from the
"carbon+water" soup. Just vaporize the water, or what ??

Otherwise it sounds just magical to me, since I read so many times that a
key disadvantage of pyrolysis is to start carbonization only after the
feedstock has dryed... So I can't understand why there has not been more
research/interest  for the hydrothermal approach ?!

Sincerely yours,
Christelle

On 8/17/07, Gerald Van Koeverden <vnkvrdn at yahoo.ca> wrote:
>
> Ron,
>
> Below, I've copied a copy of my correspondence with Dr. Antonietti.
> Note that the catalyst is no problem at all.
>
> Gerrit
>
> Dear Gerald,
>
> 1) It works with all the biomass, but at different conditions.
> Lignified cellulose relies on "melting" (it is a plastified
> melting...) which occurs for pure cellulose beads at around 215 °C,
> it is a slight increase of conditions.
> Mixed with other stuff it occurs and around 190 °C, so branches
> vanish completely in the lower range. This depends on "purity". We
> work with 2 cm pieces max. with only little loss in efficiency. It is
> like boiling vegetable soup.
>
> 2) It depends what you want. For "soil applications", you prefer a
> "hydrophilic coal", and you need not catalyst at all, only weakly
> acidic conditions.
> Fe, Cu, and Ag are only needed when you do "engineering carbons",
> i.e. with much higher structural density. But iron is not a problem:
> 4 % of the earth crust is made of ironoxides, and any red soul is
> full of it. Sounds maybe strange, but red soil works perfect as a
> catalyst. No cost, no removal...
>
> 3) Talking glucose, starch, and saccharides, this is easy: 70 - 80 %
> of the energy stored in the plant goes into the carbon, about 20 - 30
> % are liberated in the process. This is really a lot of heat: If you
> treat 1 kg of sugar, you get about 500 g of coal, but energy as you
> would have 200 g of the sugar! Close to a shell...
>
> Biomass is more complex, no energy again from fats, amino acids, and
> lignin. This gives a factor which can reduce energy gain to 5 - 10 %,
> i.e. the process is essentially for free, but not more.
>
> Thanks, indeed, for the interest.
> Markus Antonietti
>
>
> > Dear Dr. Markus Antonietti,
> >
> > As members of the Petra Terra listserve of the Hypography.com
> > Science Forum, we are excited by your research work in carbonizing
> > biomass for the purposes of building terra preta soils. We have
> > read several articles on your work with the hydrothermal
> > carbonization of plant material. After some discussion, we have a
> > few questions for clarification purposes:
> >
> > 1. Types of materials that can be used: you mention that your
> > process focusses on annual fast-growing plant materials. Thus,
> > should we assume that woody or lignified plant materials are too
> > dense for use in the 200 degree C steam pressure vessel? If they
> > can be used, to what extent do they have to be ground/milled?
> >
> > 2. The catalysts:   What is the cost of the catalysts per unit of
> > output as used in the process? In the article "Back to Black", you
> > mention catalysts of iron ions and iron oxide nanoparticles.  Is it
> > practical to recover them for re-use?
> >
> > 3. Net energy output:  It takes a certain amount of heat to get the
> > process started. At a certain point, an exothermic reaction takes
> > over. What is the net energy output/dry weight of biomass?
> > Looking forward to your kind assistance.  I will post your answers
> > on the Petra Terra list-serve.
> >
> > Gerald van Koeverden
>
> On 17-Aug-07, at 11:28 AM, Ron Larson wrote:
>
> > Gerald, Tom etl
> >
> > 1.  Thanks for forwarding this new (to me) short summary article
> > you cite below.  We had a bit of discussion on this topic a few
> > months back.  For instance, see: http://bioenergylists.org/
> > pipermail/terrapreta_bioenergylists.org/2007-April/000503.html and
> > /
> > 2007-May/000861.html (and there are others)
> >
> > 2.  I personally find this report fascinating and credible.
> > Credible because Professor Antonietti is clearly a very
> > accomplished scientist and the Max Planck Institute is well
> > respected as well.  He has nothing to gain and a lot to lose by
> > reporting a non-starter.
> >
> > 3.  A good friend (Ron West - retired ChE professor) and I have
> > tried to communicate with this group - and have had some success in
> > getting additional research results.  But your forwarded article is
> > better than anything else we have found.  Unfotunately, it still
> > doesn't say what we really need.  That is - more about the catalyst
> > that is being used, and its form - and details on pressure and
> > temperature.  The article you cite doesn't say what others have
> > said on the catalyst - "iron" (and maybe "iron oxide").  Presumably
> > there are patent issues.  But we need others to be duplicating
> > their results - and I am not aware of any.
> >
> > 4.  The other articles we have seen have not reported on the big
> > potential for liquid fuels with these nanoparticles as a starting
> > point - so "terra preta" may be hard pressed to compete.  It was
> > good to see Professor Antonietti emphasizing the soil amendment
> > aspects of his invention.  I include several from the MP Institute
> > in this response, hoping to bring them closer to the soil testing
> > side that Tom Miles keeps emphasizing and so many on this list want
> > to participate in.
> >
> > 5.  This week's dialog on where to do processing is directly
> > pertinent here - as this reputedly is a simple (low cost?) process
> > that could be farm-based.  I don't see the word "solar" here, but
> > think the needed starting energy could be from that source.
> >
> > Again - thanks for bringing us to this topic once more.
> >
> > Ron
> >
> > ----- Original Message ----- From: "Gerald Van Koeverden"
> > <vnkvrdn at yahoo.ca>
> > To: "Tom Miles" <tmiles at trmiles.com>
> > Cc: "'terra preta'" <terrapreta at bioenergylists.org>
> > Sent: Friday, August 17, 2007 7:14 AM
> > Subject: Re: [Terrapreta] Farm Produced Biochar
> >
> >
> >> Tom,
> >>
> >> Do you think that hydrothermal carbonization has any future??
> >>
> >>
> >> "http://www.mpg.de/english/illustrationsDocumentation/multimedia/
> >> mpResearch/2006/heft03/3_06MPR_20_25.pdf"
> >>
> >>
> >> Gerrit
> >>
> >> _______________________________________________
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> >
>
>
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