ISBN : 978-602-17761-4-8
40
Proceedings of 2
nd
REPTech Crowne Plaza Hotel, Bandung, November 15-17, 2016
© 2016 Published by Center for Pulp and Paper through 2
nd
REPTech
3 4
5 6
7 8
0,4 0,45
0,5 0,55
0,6 0,65
Wood basic density, gcm
3
D e
li g
ni fi
c a
ti o
n in
te n
s it
y L
n. tr
a n
s f
R = - 0,4478 R
2
= 0,2005
B
3 4
5 6
7 8
1,25 1,45
1,65 1,85
2,05 SyringilVanillin Ratio
D e
li g
n if
ic a
ti o
n i
n te
n s
it y
L n
. tr
a n
s f
R = +0.4501 R
2
= 0.2026
A
3 4
5 6
7 8
24 25
26 27
Wood initial lignin content,
D e
li gni
fi c
a ti
on i nt
e ns
it y
Ln. tr
a ns
f
R = + 0.2623 R
2
= 0.0688
ns
C
Figure 3. Correlation between syringl-to-vanillin SV unit ratio and deligniication intensity A; between wood basic density and deligniication intensity B; and between wood initial lignin content
and deligniication intensity C
2 4
6 8
10 12
14 16
18 20
22
3 4
5 6
7 8
Delignification intensity, ln transformation
P ul
p r ej
ec t,
Sengon Gmelina
Meranti kuning Kapur
R = - 0,7739
37 39
41 43
45 47
49 51
3 4
5 6
7 8
Delignification intensity, ln transformation
Sc r
e e
n e
d -p
u lp
y ie
ld ,
Sengon Gmelina
Meranti kuning Kapur
R = + 0.3529
Figure 4. Correlation of actual deligniication intensity with consecutively screened-pulp yield A; and with pulp rejects B
Regarding the initial lignin content, despite signiicant variation among the four FP woods Table 1, its insignicant correlation with actual deligniication intensity Figure 3c suggested that such variation
to some particular range did not affect the deligniication kinetics [1,6]. About wood density, its lower role despite existing on actual deligniication intensity than SV ratio was also explicable Figure 3b.
Theoretically woods with greater density necessitated more energy input for the deligniication process. This meant deligniication of greater-density PF woods would require e.g. greater H-factor as well, in
cooking; and vice versa. However, such was not too problematic to some extent for kraft cooking, as the strong alkaline liquor during the kraft cooking could diffuse at nearly almost equal rate in longitudinal,
radial, and tangential directions of the cooked wood chips [6,8]. .
The greatest role of SV ratio at the initial wood lignin entity on deligniication intensity Figure 3a indicatively owed to the more possibility of reaction mechanism I Figure 5 particularly for FP
ISBN : 978-602-17761-4-8
41
Proceedings of 2
nd
REPTech Crowne Plaza Hotel, Bandung, November 15-17, 2016
© 2016 Published by Center for Pulp and Paper through 2
nd
REPTech
woods with higher SV ratios, such as gmelina and sengon Table 1, i.e. de-methylation de-alkilation on fragmented lignins, thereby rendering them more soluble; in addition to the regular deligniication
that prevalently occurs through the cleavage of α-O-4 and β-O-4 bonds at the lignin during the kraft cooking [6,10]. This situation induced more intensive iber separation; and explained greater screen-
pulp yield and concurrently lower pulp reject from meranti kuning and kapur woods Figures 2c and 2d. Conversely, lignin with lower SV ratio that implied containing more vanillin units Figure 1 such
as meranti kuning and meranti, might inlict more possibility on mechanism reaction II condensation between the fragmented lignins that afforded greater-sized fragments aggregates which were less
soluble Figure 6. Such phenomena besides retarding deligniication rate intensity could also induce more severe degradation on wood carbohydrates esp. cellulose and hemicellulose.
It seemed that such condensation and degradation occurrence contributed their role signiicantly in decreasing the screened-pulp yields from meranti kuning and kapur woods with the elevated H-factor;
and also their lower screened-yields than from gmelina and sengon woods Figures 2c. Further beyond 1502.25 H-factor, condensation reaction during the kraft cooking of meranti kuning and kapur woods
apparently became more intensive that rendered their pulp rejects increasing to the point which exceeded the rejects from gmelina and sengon Figure 2d.
4.4. Physical and Strength Properties of Kraft Pulp Sheet
