Re: flash carbonization of biomass

["Ron Larson" <ronallarson@qwest.net>]

Michael (cc stoves)

    I looked at your site
(http://www.soest.hawaii.edu./HNEI/R3proj.html#Anchor-High-Yield-47747) and
found a little more than in your note.  Thanks for sending us this
information and congratulations at finding a fast new means of pyrolysis.  I
am afraid I still haven't understood the process - and I understand the need
for doing more development work - and for protecting patents, etc.  I am
sure we all wish you great success for pursuing your new,  higher pressure,
lower energy approach - and of hearing more as you make further progress.

    However, I presume that your announcing this does allow you also to
suggest whether there is a possible small-scale approach possible for
home-based simple cook-stoves.  Higher pressure would usually equate to
higher cost, but perhaps not.   Certainly producing large amounts of
charcoal quickly should eventually suggest also lower cost charcoal
briquettes for home use.  But I am also asking whether you think charcoal
making stoves (two outputs:  cooking and charcoal) are possible that employ
your new discoveries?  Are there fundamental reasons to recommend persons on
this list interested in small cook-stoves to stay away from high-pressure
approaches ?  (I am thinking of something like a pressure cooker - which is
not an outrageous complexity or price.)  You still must have a good bit of
"waste" energy.  Do you think it is still possible to use that for rural
bakeries, brick kilns, etc?

    Thanks in advance for any insights on the possible applicability of your
exciting announcement to very small scales.

Ron



----- Original Message -----
From: Michael J. Antal, Jr. <mantal@hawaii.edu>
To: Stoves@Crest. Org <stoves@crest.org>
Sent: Monday, December 24, 2001 12:25 PM
Subject: flash carbonization of biomass


> Dear friends: probably you recall that our fundamental research concerning
> the effects of pressure on biomass pyrolysis led us to the discovery that
> near-theoretical yields of carbon (charcoal) can be obtained from all
sorts
> of biomass with short reaction times (ca. 60 min) when pyrolysis is
> conducted at elevated pressure (ca. 100 psig).  Although the energy input
to
> our pilot plant was small, last March an engineer expressed concerns about
> it to us.  Consequently, we began to explore new ways of operating our
> equipment in order to reduce the energy input.  Not long thereafter we
> learned how to deliver very small amounts of air to the reactor and burn
the
> combustible pyrolytic vapors while retaining a high yield of charcoal.
Our
> data indicates that charcoal can be produced from all sorts of biomass at
> elevated pressures in near-theoretical yields with cooking times of less
> than 30 min and negligible energy input.  For some feedstocks a processing
> time of 15 to 20 min appears to be practical.  The yield of tar is
> negligible.  In light of the incredibly short reaction times that we now
> employ, we refer to our new process as "flash carbonization".  A summary
of
> some of our results is now posted on the HNEI web site (see below).  I
> emphasize that these early results have not been optimized, and that we
> expect to realize some further improvements in the fixed-carbon yield and
> reductions in the reaction time in the near future.  In summary, it is now
> possible to convert a one ton (or a ten ton) batch of wood (or sawdust or
> rice hulls or corn cobs) into high-yield charcoal with a processing time
of
> less than 30 min and negligible energy input.
>
> As a result of this progress, the University of Hawaii has given me a
grant
> to build a demonstration scale reactor that will be used to convert the
> University's green wastes into marketable charcoal.  Here in Hawaii the
> markets for charcoal include potting media for orchids and ornamental
> plants, barbeque charcoal for our restaurants, and charcoal as a clean
> renewable substitute for imported coal.  The capital cost of the
> demonstration reactor will be less than $50,000.  The capital cost of a
> commercial reactor that produces ca. 50 tons per day of charcoal should
not
> exceed $100,000.
>
> I will give our first technical presentation on this work at the ThermoNet
> meeting in Graz on 10 January.  Consequently, I will be away from my
office
> until mid-January.  I expect that we will publish these findings in about
> six months.  When this occurs, I will post a summary on the HNEI web site.
>
> Thanks for your interest.  I give you my best wishes for the holidays.
>
> Michael J. Antal, Jr.
> Coral Industries Distinguished Professor of Renewable Energy Resources
> Hawaii Natural Energy Institute
> University of Hawaii at Manoa
> Honolulu, HI 96822
>
> Phone: 808/956-7267
> Fax: 808/956-2336
> http://www.soest.hawaii.edu./HNEI/
>


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