Prsentation PowerPoint

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GREENTECH 2002
VALORISATION OF CEREAL STRAWS THROUGH SELECTIVE
SEPARATION OF CELLULOSE, LIGNINS AND
HEMICELLULOSES
Michel DELMAS Professor, University of
Toulouse, National Polytechnic Institute Departmen
t of Chemistry With Kham Long, Gérard Avignon,
Yves Le Bigot and the Compagnie Internationale
de la Matière Végétale (C.I.M.V.) Paris - France
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GREENTECH 2002
There is not today any technology at industrial
scale which can use cereal straws (wheat, barley,
rice,) to make pulp in good environmental
conditions in Europe, North America and other
part of the world.
Small factories using soda operate in Africa and
Asia to make low quality pulps with a huge
pollution of rivers which threatens in many place
the supply of potable water.
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GREENTECH 2002
Cereal straws are produced all around the world.
1/3 at least are burned or decayed. That means
400 millions tons which can be used to make pulp
without any interactions with an other
valorisation.
The straw fibers (rice, wheat, barley,) are
generally too short to make good mechanical
pulp. There is too high silica content to use
classical soda pulp technology which forbid the
recycling of black liquor with a recovery boiler.
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GREENTECH 2002
The only technology which can solve the problem
is an organosolve technology Organic solvents in
due conditions may allow the separation of the
main components of the vegetable matter to make
chemical pulp and valuable chemicals from lignins
and hemicelluloses
Different type of solvents have been used
methanol, ethanol, acetone, ethyl acetate, formic
acid, acetic acid etc The experimental
conditions and the quality of the produced pulp
have not permit, till today, an industrial
development in good economical and ecological
conditions.
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GREENTECH 2002
We have found that the use in well checked
proportions of a mixture of formic acid, acetic
acid and water allows the separation of
cellulose, lignins and the constitutive sugars of
hemicelluloses without degradation at atmospheric
pressure and a temperature range around
95C. The chemical and mechanical
characteristics of the pulp obtained are similar
than paper pulp obtained with caustic soda /
anthraquinone. We have named the technology
The AVIDEL Process
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The
The
AVIDEL Process
AVIDEL Process
Cereal straws, hard wood,
sugar cane bagasse, hemp
etc
Acetic acid
Formic acid, water
Oxygen peroxyde
Low molecular
Hemicellulose syrup
weight lignins
Raw and bleached
cellulosic fibers
Wood
Polymers
adhesives
Plant
sugars
minerals
Commercial pulp
Furfurole
Ethanol
and
derivatives
GREENTECH 2002
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The key points are the good management of water,
formic acid, acetic acid and silica including
recycling. We call our system a catalyst /
solvent system where - silica is located in
pulp - bleaching is made without water waste,
with peroxyacids generated in situ with
H2O2. - low molecular weight lignins and sugars
from hemicelluloses are easily separated for
further valorisation.
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GREENTECH 2002
Rice straw pulping
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Rice straw pulping
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Rice straw pulping the silica management
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GREENTECH 2002
Rice straw pulping the silica management
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Wheat straw pulping delignification
Peroxy-acids synthesis
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Wheat straw pulping delignification
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Wheat straw pulping delignification
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Wheat straw pulping delignification
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Wheat straw pulping bleaching
Bleaching with one H2O2 stage
Bleaching conditions 4 H2O2/pulp (10
consistency), 1 hour, 90C, pH 12
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GREENTECH 2002
LIGNINS
Low molecular weight 1000 lt M lt 1600 Can be
include in polyurethanes and polyesters to make
wood adhesives, insulation board, Can replace
the phenol for most of its applications
HEMICELLULOSES
Mainly xylose syrup Can be use as material
for ethanol biosynthesis raw xylitol can be
obtained after hydrogenation
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GREENTECH 2002