Dear Mike and all:
For those of you who prefer charcoal, let me recommend keeping up with
Prof.
Mike Antal at U. of Hawaii. His process, using modestly high
pressures (10
atm?) produces in excess of 40% charcoal while most processes are lucky
to
hit 25%.
It is unfortunate that he hasn't been able to commercialize it yet.
We can
hope that the U. Hawaii pilot plant will carry it forward.
Good luck to Mike...
TOM REED
BEF STOVEWORKS BEF GASWORKS
In a message dated 12/24/01 11:25:17 AM Pacific Standard Time,
mantal@hawaii.edu writes:
<<
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 â€flash carbonizationâ€.
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
Universityâ€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 968 >>
-
Stoves List Archives and Website:
http://www.crest.org/discussion/stoves/current/
http://www.ikweb.com/enuff/public_html/Stoves.html
Stoves List Moderators:
Ron Larson, ronallarson@qwest.net
Alex English, english@adan.kingston.net
Elsen L. Karstad, elk@wananchi.com www.chardust.com
List-Post: <mailto:stoves@crest.org>
List-Help: <mailto:stoves-help@crest.org>
List-Unsubscribe: <mailto:stoves-unsubscribe@crest.org>
List-Subscribe: <mailto:stoves-subscribe@crest.org>
Sponsor the Stoves List: http://www.crest.org/discuss3.html
-
Other Biomass Stoves Events and Information:
http://www.bioenergy2002.org
http://solstice.crest.org/renewables/biomass-info/
http://solstice.crest.org/renewables/biomass-info/carbon.shtml
For information about CHAMBERS STOVES
http://www.ikweb.com/enuff/public_html/Chamber.htm
