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3.2 Effect of Cooking Temperature on HexA Content and Kappa Number of Pulp
We investigated KP cooking and PS-AQ cooking under two levels of temperatures. Table 3 shows the
effect of cooking temperature on HexA content and kappa number of kraft pulp. Table 4. shows the effect
of cooking temperature on HexA content and kappa number of PS-AQ pulp.
The kappa number tended to decrease at high temperature. There was a similar
tendency to the addition of PS-AQ. On the other hand, HexA content does not seem to change.
3.3 Comparison of Pulp Yield and HexA Content between Addition of PS and AQ.
In this study, pulp yields were evaluated between KP and PS-AQ cooking. Some technologies for
improvement of pulp yield have already been developed and applied. PS and AQ have been added
to a kraft cooking process to improve pulp yield. Compared to KP cooking, an about 6 yield increase
is obtained by the PS-AQ cooking. Table 5. shows the comparison of pulp yield and HexA content between
addition of PS and AQ.
Table 1. Effect of Liquor to Wood Ratio on Kraft Cooking.
Liquor ratio LW PolysulideS AQ SAQ
Pulp yield HexA mmolkg
Kappa no. Kraft 1
5 57.5
34.5 23.0
Kraft 2 2.75
56.0 33.9
16.9 Notes: Temperature: 145°C; AA:18; Sulidity: 20.
Table 2. Effect of Liquor to Wood Ratio on PS-AQ Cooking.
Liquor ratio LW PolysulideS
AQ SAQ Pulp yield
HexA mmolkg Kappa no.
PS-AQ 1 5
1.49 0.05
61.5 34.6
16.9 PS-AQ 2
2.75 1.49
0.05 60.8
35.3 12.8
Notes: Temperature: 145°C; AA:18; Sulidity: 20.
Table 3. Effect of Cooking Temperature on Hexa Content and Kappa Number of Kraft Pulp.
Temperature Polysulide S
AQ Pulp yield
HexA Kappa no.
°C SAQ
mmolkg Kraft 1
145 55.6
34.5 23.0
Kraft 3 165
55.5 24.9
8.6 Notes: Liquor ratio: 5; AA:18; Sulidity: 20.
Table 4. Effect of Cooking Temperature on HexA Content and Kappa Number of PS-AQ Pulp.
Temperature Polysulide S
AQ Pulp yield
HexA Kappa no.
°C SAQ
mmolkg PS-AQ 1
145 1.49
0.05 61.5
34.6 16.9
PS-AQ 3 165
1.49 0.05
55.8 38.8
8.6 Notes: Liquor ratio: 5; AA:18; Sulidity: 20.
Table 5. Comparison of Pulp Yield and HexA Content between Addition of PS and AQ.
Sulidity PolysulideS
AQ Pulp yield
HexA Kappa no.
Reject SAQ
mmolkg Kraft 1
20 55.6
34.5 23.0
1.72 Kraft 4
40 57.5
31.1 19.7
0.31 PS
20 1.11
60.6 34.0
20.5 0.08
PS-AQ 1 20
1.49 0.05
61.5 34.6
16.9 PS-AQ 4
20 1.86
0.05 Not be de-ibered
Notes: Temperature: 145°C; Liquor ratio: 5; AA:18.
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This result addition of PS and AQ to a kraft cooking process has a synergistic effect on pulp yields.
However, when PS-AQ 4 pulps were prepared with 1.86 of polysulide, this is not be de-ibered.
4. Conclusion
