1Götz Martin, Institute of Forest Utilization and Work Science
Albert-Ludwigs-Universität Freiburg, Germany
IUFRO All-Division-5 Conference“Forest Products and Environment – A Productive
Symbiosis”October 29 – November 2, 2007
Taipei, Taiwan
Wood and Fibre properties of Norway spruce (Picea abies) and Scots pine (Pinus
sylvestris) and their impact on the quality of stone groundwood pulp
Götz Martin, Gero Becker, Heiner Grussenmeyer,
Leif Nutto, Peter Neukum
3Götz Martin, Institute of Forest Utilization and Work Science
Albert-Ludwigs-Universität Freiburg, Germany
Introduction (1)
• difficult situation for the European pulp and paper industry
– increasing costs for energy and raw materials
– overcapacities on the paper market
– old machinery– very competitive pulp and
paper mills in South America and China
Preisentwicklung Papierindustrie
0
20
40
60
80
100
120
140
160
180
2000 2001 2002 2003 2004 2005 2006 2007
Pre
isin
de
x [
%]
Erzeugerpreis Holzpreis Energiepreis
price development pulp & paper industry
electricity pulpwood publication paper
Fig. 2: price development pulp & paper industry
4Götz Martin, Institute of Forest Utilization and Work Science
Albert-Ludwigs-Universität Freiburg, Germany
Introduction (2)
• Picea abies pulpwood shortages on the German wood market
– booming sawing industry
– bioenergy– sivilcultural
management concepts
Is the utilization of alternative tree species like Pinus sylvestris a possible solution for this problem?
Fig. 3: empty woodyard at Stora Enso Reisholz Mill
5Götz Martin, Institute of Forest Utilization and Work Science
Albert-Ludwigs-Universität Freiburg, Germany
State of knowledge – wood and fibre properties
• P. sylvestris has in average:– shorter average fibre length than P. abies (Duchesne et al.
1997; Sirviö 2000; Wilhelmsson et al. 2002) but also higher average fibre length is reported (Fengel & Grosser 1976)
– larger fibre diameter than P. abies (Ekenstedt et al. 2003)– larger cell wall thickness and coarseness than P. abies
(Sirviö 2000; Ekenstedt et al. 2003)– higher basic density than P. abies (Loskant 1983; Dinwoodie
1996; Ekenstedt et al. 2003; Fengel & Wegener 2003)– higher extractives content than P. abies (Brandal 1966;
Kamutzki 1983; Fengel & Wegener 2003)
6Götz Martin, Institute of Forest Utilization and Work Science
Albert-Ludwigs-Universität Freiburg, Germany
State of knowledge – pulp and paper properties
• Groundwood (of scots pine)– higher yield per m³ due to higher
density– lower strength properties at a
given specific energy consumption (SEC) than P. abies (Blechschmidt et al. 1985; Kärna 1996; Putz & Göttsching 1988)
– slightly lower brightness than P. abies (Putz & Göttsching 1988)
– problems with resin can occur during the grinding and the papermaking process (Blechschmidt et al. 1985; Putz & Göttsching 1988)
Fig. 4: atmospheric chain grinder
7Götz Martin, Institute of Forest Utilization and Work Science
Albert-Ludwigs-Universität Freiburg, Germany
State of knowledge – pulp and paper properties
• Thermo-mechanical pulp:– slightly lower strength properties than spruce
assortments (Duchesne et al. 1997)– for strength spruce fibres should be preferred
(Kärenlampi 1992)
• Chemical pulp– slightly lower strength properties than spruce
chemical pulp (Kärenlampi 1992)
8Götz Martin, Institute of Forest Utilization and Work Science
Albert-Ludwigs-Universität Freiburg, Germany
Material and Methodology
• Mill scale grinding trials with an atmospheric chain grinder
• Laboratory scale oxidative (hydrogen peroxide) bleaching
• Fiber maceration with acetic acid and hydrogen peroxide (fibre analysis with Mezzo Fibre Lab 3)
Fig. 5: Pinus sylvestris pulpwood
9Götz Martin, Institute of Forest Utilization and Work Science
Albert-Ludwigs-Universität Freiburg, Germany
Material and Methodologylogging
storage on wood yard
cut to length/ debarking
marking
stem selction
grinding
pulp sampling
pulp and paperanalysis bleaching
stem selection
fiber macceration
wood analysis
data analysis
Fig. 4: Trial layout
10Götz Martin, Institute of Forest Utilization and Work Science
Albert-Ludwigs-Universität Freiburg, Germany
Material and Methodology – wood and fibre properties of Pinus sylvestris and Picea abies
Age Moisture content (%)
Density (g/cm³)
Ring width (mm)
Pinus sylvestris
36 42,1 0,45 1,96
Standard deviation
7 4,1 0,03 0,72
Picea abies 22 47,7 0,40 3,12
Standard deviation
7 7,1 0,04 0,95
11Götz Martin, Institute of Forest Utilization and Work Science
Albert-Ludwigs-Universität Freiburg, Germany
Material and Methodology – wood and fibre properties of Pinus sylvestris and Picea abies
Latewood (%)
Juvenile wood (%)
Fibre length (mm)
Fibre width (µm)
Pinus sylvestris
19,5 37,2 3,19 26,0
Standard deviation
3,3 13,3 - -
Picea abies 13,9 71,3 2,86 22,3
Standard deviation
4,7 21,1 - -
12Götz Martin, Institute of Forest Utilization and Work Science
Albert-Ludwigs-Universität Freiburg, Germany
Results – pulp and paper propertiesFreeness (Schopper-Riegler)
Relationship between specific energy consumption and freeness (Schopper-Riegler)
68
70
72
74
76
78
80
82
84
1000 1100 1200 1300 1400 1500 1600
specific energy consumption (kWh/t)
free
nes
s (S
R)
Pinus sylvestris Picea abies
Logarithmisch (Pinus sylvestris) Logarithmisch (Picea abies)
13Götz Martin, Institute of Forest Utilization and Work Science
Albert-Ludwigs-Universität Freiburg, Germany
Results – pulp and paper propertiesFreeness (SR)
Freeness (Schopper-Riegler) at specific energy consumption of 1.200 kWh/t
71,5
72,0
72,5
73,0
73,5
74,0
74,5
75,0
75,5
Pinus sylvestris Picea abies Picea abies_high density
Fre
enes
s (S
R)
14Götz Martin, Institute of Forest Utilization and Work Science
Albert-Ludwigs-Universität Freiburg, Germany
Results – pulp and paper propertiesSheet density (g/cm³)
Relationship between specific energy consumption and sheet density
0,4
0,42
0,44
0,46
0,48
0,5
0,52
0,54
0,56
1000 1100 1200 1300 1400 1500 1600
specific energy consumption (kWh/t)
shee
t d
ensi
ty (
g/c
m³)
Pinus sylvestris Picea abies Linear (Picea abies) Linear (Pinus sylvestris)
15Götz Martin, Institute of Forest Utilization and Work Science
Albert-Ludwigs-Universität Freiburg, Germany
Results – pulp and paper propertiesSheet density g/cm³)
Sheet density at specific energy consumption of 1.200 kWh/t
0,380
0,400
0,420
0,440
0,460
0,480
0,500
0,520
Pinus sylvestris Picea abies Picea abies_high density
Sh
eet
den
sity
(g
/cm
³)
16Götz Martin, Institute of Forest Utilization and Work Science
Albert-Ludwigs-Universität Freiburg, Germany
Results – pulp and paper propertiesTensile Index (Nm/g)
Relationship between specific energy consumption and tensile index
20
25
30
35
40
45
50
1000 1100 1200 1300 1400 1500 1600
specific energy consumption (kWh/t)
ten
sile
ind
ex (
Nm
/g)
Pinus sylvestris Picea abies Linear (Picea abies) Linear (Pinus sylvestris)
17Götz Martin, Institute of Forest Utilization and Work Science
Albert-Ludwigs-Universität Freiburg, Germany
Results – pulp and paper propertiesTensile Index (Nm/g)
Tensile index at specific energy consumption of 1.200 kWh/t
0,0
5,0
10,0
15,0
20,0
25,0
30,0
35,0
40,0
45,0
Pinus sylvestris Picea abies Picea abies_high density
Ten
sile
ind
ex (
Nm
/g)
19Götz Martin, Institute of Forest Utilization and Work Science
Albert-Ludwigs-Universität Freiburg, Germany
Results – pulp and paper propertiesPorosity (Bendtsen)
Porosity (Bendtsen) at specific energy consumption of 1.200 kWh/t
0
50
100
150
200
250
300
350
Pinus sylvestris Picea abies Picea abies_high density
Po
rosi
ty (
ml/m
in)
20Götz Martin, Institute of Forest Utilization and Work Science
Albert-Ludwigs-Universität Freiburg, Germany
Results – pulp and paper propertiesISO-brightness
ISO-brigthness at specific energy consumption of 1.200 kWh/t
61,0
62,0
63,0
64,0
65,0
66,0
67,0
68,0
Pinus sylvestris Picea abies Picea abies_high density
ISO
-bri
gh
tne
ss
21Götz Martin, Institute of Forest Utilization and Work Science
Albert-Ludwigs-Universität Freiburg, Germany
Results – pulp and paper propertiesBleachability with hydrogen peroxide
Bleachability of Pinus sylvestris and Picea abies groundwood pulp
0
10
20
30
40
50
60
70
80
90
ISO-Brightness(unbleached)
ISO-Brightness (bleached) delta
ISO
-Bri
gh
tnes
s (%
)
(Bleaching with 4% hydrogen-peroxide, bulk density 25%, bleaching duration 2 hours)
(Bleaching experiment with frozen groundwood - lower ISO brightness because of this)
22Götz Martin, Institute of Forest Utilization and Work Science
Albert-Ludwigs-Universität Freiburg, Germany
Results – pulp and paper propertiesSpecific energy consumption (kWh/t)
Specific energy consumption required to reach freeness 75 SR
1000
1100
1200
1300
1400
1500
1600
1700
68 70 72 74 76 78 80 82 84
Freeness (SR)
spec
ific
en
erg
y c
on
sum
pti
on
(k
Wh
/t)
Pinus sylvestris Picea abies
Exponentiell (Pinus sylvestris) Exponentiell (Picea abies)
23Götz Martin, Institute of Forest Utilization and Work Science
Albert-Ludwigs-Universität Freiburg, Germany
Results – pulp and paper propertiesSpecific energy consumption (kWh/t)
Specific Energy Consumption at Freeness 75 SR
1100
1150
1200
1250
1300
1350
Pinus sylvestris Picea abies Picea abies_high density
Sp
ecif
ic E
ner
gy
Co
ns
um
pti
on
(kW
h/t
)
24Götz Martin, Institute of Forest Utilization and Work Science
Albert-Ludwigs-Universität Freiburg, Germany
Discussion
• pulp and paper quality of Pinus sylvestris pulpwood can be explained due to:
– fibre morphology– chemical properties
• lignin content• extractives
25Götz Martin, Institute of Forest Utilization and Work Science
Albert-Ludwigs-Universität Freiburg, Germany
Discussion
• fibre morphology– fibre width
• reduced tensile index with increasing fibre width (Kärenlampi 1992; Corson 1999)
• higher porosity with increasing fibre width (Kärenlampi 1992; Corson 1999)
– cell wall thickness• fibres of P. sylvestris are stiffer than fibres of P. abies and
break in a earlier stage in the grinding process and result in low pulp fibre length and low tear strength
26Götz Martin, Institute of Forest Utilization and Work Science
Albert-Ludwigs-Universität Freiburg, Germany
Discussion
• chemical properties– lignin content
• due to the higher lignin content a higher amount of energy and/or heat is required during the grinding process (Sundholm et al. 1999)– the grinding process has to be adjusted for P. sylvestris– differences between P. sylvestris and P. abies diminish when
using the PGW process (Kärna 1986)
– extractives• high amount of extractives cause low strength properties
(Brandal 1966)• extractives (Pinosylvin) induce lower pulp brightness
(Blechschmidt et al. 1985)
27Götz Martin, Institute of Forest Utilization and Work Science
Albert-Ludwigs-Universität Freiburg, Germany
Conclusion
• P. sylvestris can be used as a raw material for the groundwood process but the pulp and paper quality is lower than using P. abies
• due to the different fibre morphology and the different chemical properties the process technology should be adjusted
• the utilization of P. sylvestris pulpwood can be advantageous as a result of:
– better availability– lower purchasing price– higher yield
28Götz Martin, Institute of Forest Utilization and Work Science
Albert-Ludwigs-Universität Freiburg, Germany
Thanks for your attention
Götz Martin
Institute of Forest Utilization and Work Science
Albert-Ludwigs-Universität Freiburg, Germany
Tel: 0049-761 - 203 9242
E-Mail: [email protected]
29Götz Martin, Institute of Forest Utilization and Work Science
Albert-Ludwigs-Universität Freiburg, Germany
Material and Methodology
Fig. 5: Marked (spruce) pulpwood
30Götz Martin, Institute of Forest Utilization and Work Science
Albert-Ludwigs-Universität Freiburg, Germany
Material and Methodology
Fig. 6: Log saw
Fig. 7: Debarking drum
31Götz Martin, Institute of Forest Utilization and Work Science
Albert-Ludwigs-Universität Freiburg, Germany
Material and Methodology
Fig. 8: Stem selection
32Götz Martin, Institute of Forest Utilization and Work Science
Albert-Ludwigs-Universität Freiburg, Germany
Material and Methodology
Fig. 9: Atmospheric chain grinders at Stora Enso Reisholz mill
33Götz Martin, Institute of Forest Utilization and Work Science
Albert-Ludwigs-Universität Freiburg, Germany
Material and Methodology
Fig. 10: Pulp sampling
34Götz Martin, Institute of Forest Utilization and Work Science
Albert-Ludwigs-Universität Freiburg, Germany
Material and Methodology
Fig. 11: Pulp and paper analysis