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© 2013 Published by Center for Pulp and Paper through REPTech2012
Table 6 Temperature Condition of Production
Case 1
2 98 H
2
SO
4
241 kgh 516 kgh
H
2
O
2
59 kgh as 45
120 kgh as 60 Dilution Water
2640 kgh 4920 kgh
H
2
SO
4
H
2
O
2
3.1 mol1 mol
2.3 mol1 mol Season
Winter Winter
Summer Shortly after
reaction 96-103
o
C 91-94
o
C 105-108
o
C After Cooling
24-27
o
C 26-28
o
C 37-43
o
C Cooling Water
23-27
o
C 15-17
o
C 30-32
o
C
5. Application to Pulp Bleaching
We have established a method to continuously produce peroxymonosulfuric acid industrially. And
we applied the produced peroxymonosulfuric acid to the discoloration countermeasure of ECF bleached
pulp
8
. As a result, such merits as 1 improvement of pulp discoloration, 2 cost reduction of bleaching
chemicals, 3 reduction of energy cost, 4 production increase of pulp, and 5 reduction of waste water
COD were obtained. The irst actual equipment was supplied to the Tomioka Mill of Oji Paper Company;
and it was added to the A-stage of A—ZD—Eop—D. As a result, reduction of ClO
2
additive amount and ozone additive amount was attained; and it has been
operated smoothly without any problems caused to the product pulp
a b
.
5.1 Application to The First Stage of Bleaching No.1
In the case when discoloration countermeasures were required and the peroxymonosulfuric acid was
applied to the irst stage, we studied whether or not reduction of ClO
2
additive amount to D0 stage is possible, while maintaining the inal K value.
5.1.1 Study Example 1
1 Used pulp a Unbleached LOKP
b Properties Brightness: 46.5 , K value: 6.7, HexA: 28
μmolg, viscosity: 22.1 cP 2 Treatment conditions
The studied bleaching sequence was irst- stage—D0—Eop—D1 and we studied the effect
of introducing peroxymonosulfuric acid to the place just before the D0 stage. Table 7 shows the
treatment conditions at each stage. Preparation of peroxymonosulfuric acid was done by reacting 95
H
2
SO
4
with 45 hydrogen peroxide in 3 mol : 1 mol.
3 Results Table 8 shows the results. By applying
peroxymonosulfuric acid to the stage before the D0 stage, ClO
2
additive amount necessary to obtain same discoloration PC value and whiteness
as those without the peroxymonosulfuric acid stage was able reduced by 2 kgp - 4 kgpt. Also,
compared to the case where high-temperature acid
Table 8 Result of MPS Bleaching
Condition D0
After int. Stage Final Property
Cl0
2
Hex A Br.
Hex A Br.
K Value PC Value
Viscosity BD
µmolg µmolg
Acid cP
No MPS Treatment 1.50
- -
0.9 87.3
0.5 0.8
21.5 A
1.30 18
44.6 0.6
87.4 0.4
0.7 21.1
MPS 0.25
1.30 24
47.1 0.5
87.8 0.4
0.6 20.1
0.50 1.10
21 47.5
0.5 87.8
0.4 0.7
20.1
Table 10 Comparison with A, A and MPS
Bleaching Condition of First Stage
D0 After int. Stage
Final Property Cl0
2
Hex A Br.
Br. Viscosity
BD µmolg
cP No MPS Treatment
0.5 37
52.1 86.4
29.3 A 60
o
C pH3
0.4 35
53.1 86.8
27.5 A 85
O
C pH3
0.3 23
53.3 86.5
26.7 MPS
60
O
C 0.30
0.3 29
55.7 86.8
24.8 0.60
0.3 26
57.2 86.9
23.0 0.90
0.2 22
58.1 87.4
25.1
ISBN : 978-602-17761-0-0
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© 2013 Published by Center for Pulp and Paper through REPTech2012
treatment A , 85 °C was conducted at the stage
before the D0 stage, peroxymonosulfuric acid treatment was able to reduce ClO
2
additive amount by 0 - 2 kgpt. If there exists an acid treatment
tower, peroxymonosulfuric acid can be added to this tower as a bleaching tower before D0 treatment.
Also, if there exists an unbleached tower, it can be added to this tower as well. Meanwhile, the raw
material H
2
O
2
of 0.25 BD peroxymonosulfuric acid is equivalent to about 0.1 BD.
Table 7 Bleaching Condition of Stage
Stage PC
Temp.
O
C Time
min Fin. pH
Chemicals A
10 85
90 2.8~3.2
MPS 10
60 90
2.8~3.2 D0
10 60
60 2.7~3.0
Eop 10
65 90
11~11.3 O
2
0.2 H
2
O
2
0.3 D1
10 65
120 4.8~5.2
ClO
2
0.3
5.2 Application to The First Stage of Bleaching No. 2
