Session 3 ic2011 csoka
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Transcript of Session 3 ic2011 csoka
L. Csoka, A. Iskalieva B.M. Yimmou, M. Horvath, P. Takats, G. Grozdits
Cleaning and Modifying Wheat-Straw Pulps with Inert Gas Ultrasonification
2011 FPS 65th International Convention
P. Takats, G. Grozdits
University of West Hungary, Inst. Wood & Paper Technology, Sopron, Hungary and Louisiana Tech University, Ruston, LA, USA
Objective
• EU FP7 „SONOPULP” project - sonication of natural fibres and agro-wastes
• Create a new technology for pulping annual plants – less energy and chemicalsplants – less energy and chemicals
• Zero waste perspective• 6 countries: Spain, Netherland, Germany,
Austria, Belgium and Hungary• 5 WPs: raw materials to LCA and biogas
production, WP2 presented here
• Cavitation: is the formationof empty cavities in a liquidby high forces and the immediate implosion of them
Introduction
immediate implosion of them – Can be generated: acoustically and
hydrodynamically
Pressure of the liquid < Vapour pressure of the liquid
• 93 different chemical reactions• OH radicals, H2O2 formation• Chemical – physical effects
Introduction
• Wheat straw: screened by 5 mm hole screen• Pre-treatment in alkaline solution• Ultrasonic (batch, 150W, 50W/cm2,20 kHz) and
hydrodynamic (continuous)digestion (different consistency)
Materials and methods
• In case of ultrasonic digestion: argon, krypton and xenon inert gases has been applied
• Evaluation of yield and tensile properties
• Theoretical background
Materials and methods
= 2
2
4 dtVd
rp
πρ
(Strasberg, 1956))
Rd R
dt
dR
dtp
RdRdt R
pl
i( ) ( ) ( )2
223
21 4 2
+ = − − −
∞ρ
µ σ
100
150
200
250
300
350
400
450
500
Radius (micrometer)
-400000
-200000
0
200000
400000
600000
800000
1000000
Bulk Pressure (atm)
radius (micrometer)adiabatic phase starts hereBulk liquid Pressure (atm)
( ) ( )
−+−
−+++−+−
−++= παωξωπαω
ξπαωωξπαω
ξρtt
Rtt
RRr
p bb cos(cos(1)sin(cos(12 2
2
0
02
0
00
����( )
rfπρPγ
p0
21
3 ∞=21
00
321
= ∞
ργ
πP
fR
Bubble size distribution
0
10
20
30
40
50
0 40 80 120
160
200
240
280
320
360
400
Bubble size (10-6 m)
% No. of bubbles
R0(avg) =57.82 µm No. of Bubbles =41120
0
50
100
0 10 20 30 40 50 60
Time (microsec)
-800000
-600000
• Bubble dynamics model gives:Instantaneous value of:
- Radius
- Bubble wall velocity - Bubble wall acceleration
Results
- Bubble wall acceleration
- Pressure inside the bubble
h
d
3
22
38
cf
ρµπ
cIpa ρ2=
AW
I =
( ) 01
0
=
−∇ qpn
ρ
Results
Lignin content [%]7
8
9
10
11
9.4BC - before cookingW-US - without ultrasound treatmentAr - ultrasound with argon combinationKr - ultrasound with krypton combinationXe - ultrasound with xenon combination140, 210, 280 - ultrasound treatment with different water-fiber ratio
Yield: 50-70% in case of hydrodynamic device
40-50% in case of acoustic ultrasound device
Samples
Lignin content [%]
0
1
2
3
4
5
6 5.4
3.7
1.20.8
2.4
4.24.8
BC W-US Ar Kr Xe 140 210 280
Results
38.645.62 46.17 49.39
42.3
28.7
20
30
40
50
60
Tens
ile in
dex
0
10
1hs2hs
3hs4hs
5hs
HdC+Sommerville
Samples
Tens
ile in
dex
Results
Changes of tearing index Changes of tensile index
Results
OCH
R-COOHCOOC
O
OH
H
OCH3
COOR
COOH
COOOOOC
ROOCOOR
Increased:
carboxyl, conjugated carboxyl, phenolic OH, aromatic CH, aromatic esters
Oxidative degradation of lignin
Conclusions
• Agro-wastes, straws, stalks can be converted to valuable raw material for the paper industry
• 50-70% yield can be generated• Tensile properties acceptable• Tensile properties acceptable• Oxidative lignin degradation• Less energy and chemicals• Environmental friendly process• No wastes generated
Thank you for your attention!