THE EFFECT OF REFINING ON TRANSVERSE DIMENSION
DISTRIBUTIONS OF EUCALYPT PULP SPECIES
3rd ICEP
International Colloquium on Eucalyptus Pulp
March 4-7, 2007
Belo Horizonte, Brazil
Iiro Pulkkinen, TKK
Juhani Aittamaa, TKK
Juha Fiskari, Botnia
Contents
• Motivation
• Materials and methods
• Results
- The effect of refining on fiber transverse
property distribution
• Conclusion
• Future work
• Increasing quality requirements of paper pulp quality
• New and improved optical measuring techniques and fiber analyzers
• Kajaani FiberLab® used
polarizer capillary polarizer
Measurement optics
Length-weighted fiber length distribution
0
1
2
3
4
5
6
7
0 1 2 3 4 5 6 7
mm
%
Mean (mm)= 1,45
Length-weighted fiber length distribution
0
1
2
3
4
5
6
7
0 1 2 3 4 5 6 7
mm
%
Mean (mm)= 1,45
Aims of this study:
1. The effect of refining on transverse dimension distributions
- The effect of drying conditions
2. How fiber wall thickness distributions affect the properties of handsheets
Contents
• Motivation
• Materials and methods
• Results
- The effect of refining on fiber transverse
property distribution
• Conclusion
• Future work
• Industrial grade pulps, ECF bleached, machine dried
• Laboratory Voith Sulzer refiner (double disk)
• Stock concentration of 4%
• Specific edge load of 0.4 J/m
• Refining energies from 0 to 120 kWh/t
Pulp samples
• E. grandis/E. saligna (50/50%)
• E. nitens/E. globulus (~80/20%)
• E. urograndis
• E. grandis/E. dunnii (90/10%)
Once-dried Eucalypt samples
0
5
10
15
20
25
30
0 3 6 9 12 15
Fiber wall thickness (m)
Po
pu
lati
on
(%
)
E.nitens/E.globulus
E.urograndis
before refining
mean ( m) 3.34
variance ( m) 2.22
skewness 2.16
before refining
mean ( m) 3.29
variance ( m) 2.35
skewness 4.17
Once-dried Eucalypt samples
0
5
10
15
20
25
30
0 3 6 9 12 15
Fiber wall thickness (m)
Po
pu
lati
on
(%
)
after refining
mean ( m) 3.51
variance ( m) 2.25
skewness 1.67
after refining
mean ( m) 3.48
variance ( m) 2.16
skewness 1.26
E.nitens/E.globulus
E.urograndis
Contents
• Motivation
• Materials and methods
• Results
- The effect of refining on fiber transverse
property distribution
• Conclusion
• Future work
How refining altered the
characteristics of the
distributions
Length-weighted fiber length (mm)
0.70
0.75
0.80
0.85
0.90
E.grandis/E.saligna
E.nitens/E.globulus
E.urograndis
E.grandis/E.dunnii
E.grandis/E.saligna
E.nitens/E.globulus
E.urograndis
E.grandis/E.dunnii
Before refining =
After refining =
Once-dried Dried
Length-weighted fiber length
-6.00
-3.00
0.00
3.00
6.00
9.00
E.grandis/E.saligna
E.nitens/E.globulus
E.urograndis
E.grandis/E.dunnii
E.grandis/E.saligna
E.nitens/E.globulus
E.urograndis
E.grandis/E.dunnii
M
ean
(%
)
Once-dried Dried
Fiber width (m)
14.00
15.00
16.00
17.00
18.00
E.grandis/E.saligna
E.nitens/E.globulus
E.urograndis
E.grandis/E.dunnii
E.grandis/E.saligna
E.nitens/E.globulus
E.urograndis
E.grandis/E.dunnii
Once-dried Dried
Before refining =
After refining =
Fiber width
-6.00
-3.00
0.00
3.00
6.00
9.00
E.grandis/E.saligna
E.nitens/E.globulus
E.urograndis
E.grandis/E.dunnii
E.grandis/E.saligna
E.nitens/E.globulus
E.urograndis
E.grandis/E.dunnii
M
ean
(%
)
Dried Once-dried
Fiber wall thickness (m)
1.00
2.00
3.00
4.00
5.00
E.grandis/E.saligna
E.nitens/E.globulus
E.urograndis
E.grandis/E.dunnii
E.grandis/E.saligna
E.nitens/E.globulus
E.urograndis
E.grandis/E.dunnii
Before refining =
After refining =
Once-dried Dried
Fiber wall thickness
-6.00
-3.00
0.00
3.00
6.00
9.00
E.grandis/E.saligna
E.nitens/E.globulus
E.urograndis
E.grandis/E.dunnii
E.grandis/E.saligna
E.nitens/E.globulus
E.urograndis
E.grandis/E.dunnii
M
ean
(%
)
Once-dried Dried
Bulk (cm3/g)
R2 = 0.0024
1.55
1.6
1.65
1.7
1.75
1.8
1.85
1.9
3.00 3.10 3.20 3.30 3.40 3.50
Mean (m)Tensile index (Nm/g)
R2 = 0.0099
20
22
24
26
28
30
32
34
36
38
40
3.00 3.10 3.20 3.30 3.40 3.50
Mean (m)
• By using length-weighted fiber length, the influence of fines and cell wall fragments can be compensated
• Refining increased the mean width of once-dried eucalypt pulps
• Refining decreased the mean width of the dried fibers
• The mean of the fiber wall thickness of the once-dried eucalypt fiber samples increased
• The mean of the fiber wall thickness of the dried eucalypt fibers remained practically the same
Standard deviation of fiber length (mm)
0.20
0.25
0.30
0.35
0.40
E.grandis/E.saligna
E.nitens/E.globulus
E.urograndis
E.grandis/E.dunnii
E.grandis/E.saligna
E.nitens/E.globulus
E.urograndis
E.grandis/E.dunnii
Once-dried Dried
Before refining =
After refining =
Fiber length
-30.00
-25.00
-20.00
-15.00
-10.00
-5.00
0.00
5.00
10.00
E.grandis/E.saligna
E.nitens/E.globulus
E.urograndis
E.grandis/E.dunnii
E.grandis/E.saligna
E.nitens/E.globulus
E.urograndis
E.grandis/E.dunnii
S
tan
dard
devia
tio
n (
%)
Once-dried Dried
Standard deviation of fiber width (m)
0.00
2.00
4.00
6.00
8.00
10.00
E.grandis/E.saligna
E.nitens/E.globulus
E.urograndis
E.grandis/E.dunnii
E.grandis/E.saligna
E.nitens/E.globulus
E.urograndis
E.grandis/E.dunnii
Before refining =
After refining =
Once-dried Dried
Fiber width
-30.00
-25.00
-20.00
-15.00
-10.00
-5.00
0.00
5.00
10.00
E.grandis/E.saligna
E.nitens/E.globulus
E.urograndis
E.grandis/E.dunnii
E.grandis/E.saligna
E.nitens/E.globulus
E.urograndis
E.grandis/E.dunnii
S
tan
dard
devia
tio
n (%
)
Once-dried Dried
Standard deviation of fiber wall thickness (m)
0.0
1.0
2.0
3.0
E.grandis/E.saligna
E.nitens/E.globulus
E.urograndis
E.grandis/E.dunnii
E.grandis/E.saligna
E.nitens/E.globulus
E.urograndis
E.grandis/E.dunnii
Once-dried Dried
Before refining =
After refining =
Fiber wall thickness
-30.00
-25.00
-20.00
-15.00
-10.00
-5.00
0.00
5.00
10.00
E.grandis/E.saligna
E.nitens/E.globulus
E.urograndis
E.grandis/E.dunnii
E.grandis/E.saligna
E.nitens/E.globulus
E.urograndis
E.grandis/E.dunnii
S
tan
dard
devia
tio
n (
%)
Dried Once-dried
Bulk as a function of standard deviation of fiber wall thickness for un-refined pulp.
Bulk (cm3/g)
R2 = 0.68
1.55
1.6
1.65
1.7
1.75
1.8
1.85
1.9
2.00 2.20 2.40
Standard deviation of fiber wall thickness (m)
Tensile index as a function of standard deviation of fiber wall thickness for un-
refined pulp.
Tensile index (Nm/g)
R2 = 0.63
20
22
24
26
28
30
32
34
36
38
40
2.00 2.20 2.40
Standard deviation of fiber wall thickness (m)
Length-weighted fiber length
-0.40
-0.35
-0.30
-0.25
-0.20
-0.15
-0.10
-0.05
0.00
0.05
0.10
0.15
0.20
E.grandis/E.saligna
E.nitens/E.globulus
E.urograndis
E.grandis/E.dunnii
E.grandis/E.saligna
E.nitens/E.globulus
E.urograndis
E.grandis/E.dunnii
Skew
ness
Once-dried Dried
Before refining =
After refining =
Length-weighted fiber length
-250.00
-200.00
-150.00
-100.00
-50.00
0.00
50.00
100.00
E.grandis/E.saligna
E.nitens/E.globulus
E.urograndis
E.grandis/E.dunnii
E.grandis/E.saligna
E.nitens/E.globulus
E.urograndis
E.grandis/E.dunnii
S
kew
ness (
%)
Once-dried Dried
Fiber width
0.00
4.00
8.00
12.00
16.00
20.00
E.grandis/E.saligna
E.nitens/E.globulus
E.urograndis
E.grandis/E.dunnii
E.grandis/E.saligna
E.nitens/E.globulus
E.urograndis
E.grandis/E.dunnii
Skew
ness
Once-dried Dried
Before refining =
After refining =
Fiber width
-250.00
-200.00
-150.00
-100.00
-50.00
0.00
50.00
100.00
E.grandis/E.saligna
E.nitens/E.globulus
E.urograndis
E.grandis/E.dunnii
E.grandis/E.saligna
E.nitens/E.globulus
E.urograndis
E.grandis/E.dunnii
S
kew
ness (
%)
Once-dried Dried
Fiber wall thickness
0.00
2.00
4.00
6.00
8.00
10.00
E.grandis/E.saligna
E.nitens/E.globulus
E.urograndis
E.grandis/E.dunnii
E.grandis/E.saligna
E.nitens/E.globulus
E.urograndis
E.grandis/E.dunnii
Skew
ness
Once-dried Dried
Before refining =
After refining =
Fiber wall thickness
-250.00
-200.00
-150.00
-100.00
-50.00
0.00
50.00
100.00
E.grandis/E.saligna
E.nitens/E.globulus
E.urograndis
E.grandis/E.dunnii
E.grandis/E.saligna
E.nitens/E.globulus
E.urograndis
E.grandis/E.dunnii
S
kew
ness (
%)
Once-dried Dried
Bulk as a function of skewness of fiber wall thickness for un-refined pulp.
Bulk (cm3/g)
R2 = 0.65
1.55
1.6
1.65
1.7
1.75
1.8
1.85
1.9
1 2 3 4 5
Skewness of fiber wall thickness
Tensile index as a function of skewness of fiber wall thickness for un-refined pulp.
Tensile index (Nm/g)
R2 = 0.68
20
22
24
26
28
30
32
34
36
38
40
1 2 3 4 5
Skewness of fiber wall thickness
• Increase of the standard deviation and skewness of fiber length distribution of once-dried and dried fibers
- straightening of the fibers
- no extensive fiber cutting
• The behavior of standard deviation and skewness of fiber width was unpredictable percentual changes were significant
• The changes in standard deviation of fiber wall thickness were small for once-dried fibers and noticeable for dried fibers
• The decrease in skewness of fiber wall thickness was high for all samples
- the detachment of fragments from the fiber wall to create new particles
• Wide fiber wall thickness distributions yielded the bulkiest sheets
• Narrow fiber wall thickness distributions highest tensile strength and elastic modulus values a result of a homogeneous structure of formed sheets
Contents
• Motivation
• Materials and methods
• Results
- The effect of refining on fiber transverse
property distribution
• Conclusion
• Future work
• The response to refining of dried fibers deviated markedly from that of once-dried fibers
• Refining affected the skewness of fiber wall thickness significantly
• Narrow fiber wall thickness distributions high tensile property values
• Wide fiber wall thickness distributions high bulk
• The effect of higher distribution moment on paper technical properties can prove to be of great importance
Contents
• Motivation
• Materials and methods
• Results
- The effect of refining on fiber transverse
property distribution
- The effect of fiber wall thickness on
paper technical properties
• Conclusion
• Future work
• Fractionation of eucalyptus pulps
• The importance of mean of fiber wall thickness
• Differentiate the effect of hemiselluloce content from that of wall thickness characteristics
• Simulation of paper technical properties as a function of refining based on eucalyptus fiber morphology
Thank you for your attention!
