REVIEW OF RETTING METHODS
OSMOTIC DEGUMMING
INSTITUTE OF NATURAL FIBRES AND MEDICINAL PLANTSWojska Polskiego 71 b, 60-630 Poznan, POLAND, tel. (48 61) 845 58 00 fax. (48 61) 841 78 30
e-mail: [email protected] www.inf.poznan.pl
W. Konczewicz
Degumming of bast fibrous plants
(flax, hemp)
Water
retting Dew
retting
Chemical
degumming
Physical
methods
The leading producers of flax fibre are:
France, Belgium and the Netherlands.
Water retting
Bacteries: Bacillus amylobacter, Bacillus felsineus, Granulobacter
pectinovorum, Clostridium felsineum, Bacillus comesii rossi
Water consumption: 1t straw / 20t water and 10t for washing and rinsing.
in tank
in river (Lys, Nil)
• cold water 13-18oC• warm water 29-32oC• application of nitrogen nourishment: urea (Kozlowski 1966),
nitrate, phosphate and ammonium carbonate (Czernuszok 1982)
• with aeration (Kulas 1964)
• enzymatic retting: straw, fibre enzymes: cellulolytic, pectynolytic, hemicellulolytic,
lignocellulolytic
Now – Bulgaria
Past: All EU Countries
Warm water retting
in Egypt
Dew retting
Fungi: Clostridium herbarum, Mucor stoloniter, Mucor
hiemalis, Mucor plumbens, Aspergillus niger,
Fusarium culmorum, Epicoccum nigrum, Rhizopus sp.
• application of nitrogen nourishment
• breaking of straw in root part• application of desiccants (Purivel, Roundup)
All UE Countries
DEW RETTING IN EUROPE
Retting time - 28 to 41 days
- average temperature of 11.5 oC
- rainfall of about 32.6 mm
- temperature of 15 – 20 oC
- moisture content of air 60 %
shortest retting time:
longest retting time 70 days
optimal parameters:
- mean temperature of 15 oC
- rainfall of about 60 mm
RETTING PROCESS MONITORING
10-15 days from swathing
repeated regularly every week
at the end of the process – twice a week.
Under retted strawInitially retted strawRaw straw
Over retted straw Rotten strawProperly retted
straw
Hooked swath shaker
Self-propelled combine turning over
the swath of straw and deseeding flax
Practically the straw is being turned over once or twice.
Chemical degumming
• ethylene (Kroker 1950)
• oxalic acid (Dujaridin 1942)
• sulphuric acid (Dujaridin 1942)
• sodium hydroxide (Dujaridin 1942)
• acid and sodium carbonate (Dujaridin 1942)
• oxygenated water (Kasprzak 1983 and
Staniewicz 1983)
• soda (Ivanov et al. 1989)
• sodium sulphite (Shishko et al. 1989)
• and other
Physical methods
• ultrasound oscillation (Drozdow 1979)
• electron radiation
• steaming with application of pressure methods (Lewkowskij 1980)
• steam explosion (Kessler 1998)
- flash hydrolysis – steam hydrolysis(Sotton, Ferrari 1989; Prunier 1989)
- flash hydrolysis – steam hydrolysis (Wurster, Daul 1988)
• osmotic degumming – like conducted in Lys or Nil River (Kozlowski, Konczewicz, Allam)
• high-power electromagnetic pulses
Osmotic degumming method is based on natural
physical laws: water diffusion, osmosis and osmotic
pressure to obtain the higher quality of fiber.
Using physical laws, especially osmosis, when the inner
part of fibrous plant is in contact with water, allows for
extraction of fibers with no effect on natural features of
fiber.
The fiber obtained by this method is delicate, thin
and has color adequate to the quality of used raw
material.
This method allows for controlled water flow,
controlled pH value, temperature and time of the
process.
Osmotic degumming can be accelerated using
UTRASOUND processing.
Osmotic degumming
PCT/PL2006/000085
PCT/PL2008/000081
Lab Scale Semi-Industrial Scale Pilot Plant Scale
4,0
4,5
5,0
5,5
6,0
6,5
7,0
7,5
0 20 40 60 80 100
Degumming time [h]
pH
Warm water retting Osmotic degumming
The comparison of the post-osmosis and
post-retting liquids pH depending on the
duration of the process.
Results
0
4
8
12
16
20
0 20 40 60 80 100
Degumming time [h]
Ac
idit
y [
mv
al/l
]
water retting osmotic degumming
The comparison of post-osmosis and
post-retting liquids acidity depending on
the duration of the process
Lab scale
Semi-
industrial
scale
Cross-section through
flax fibres
magnification x 200
Flax fibres
magnification x 200
Long flax fiber
- Fineness 0.91 [tex]
- Breaking tenacity
62.79 [cN/tex]
Hackled flax fiber
- Fineness 0.71 [tex]
- Breaking tenacity
50.13 [cN/tex]
Hackled flax fiber
- sliver
- Fineness 0.54 [tex]
- Breaking tenacity
33.75 [cN/tex]
The Achievements
1 2
6 5
4 3
Control pH
Water inlet
Water solution after
osmotic treatment
Control
box
t [ C]= const.
1. Process chamber 2. Cylinder unit 3. Pump
4. Heater5. Feeding pump6. Removing pump
Poznań, POLAND
