I Advantages of oxygen delignification o Improves bleaching process efficiency O Proven technology O Spent liquor is free of chloride ions O Effluent can be handled in kraft recovery system O Decrease consumption of chemicals used in bleaching O Eases effluent discharge O OXygen cheaper than chlorine/chlorine dioxide O Essential component of future TCF or closed cycle technologies South China University of Technology
South China University of Technology Advantages of oxygen delignification ○ Improves bleaching process efficiency ○ Proven technology ○ Spent liquor is free of chloride ions ○ Effluent can be handled in kraft recovery system ○ Decrease consumption of chemicals used in bleaching ○ Eases effluent discharge ○ Oxygen cheaper than chlorine/chlorine dioxide ○ Essential component of future TCF or closed cycle technologies
a Disadvantages of oxygen delignification O Lignin selectivity limitations ○ Installation cost O Creates need for extra recovery capacity I New Development to Improve Effectiveness △ Om Process△ Peroxide-aided single and double oxygen stages ATwo oxygen addition points EFfect of matal ions A Lignin activation before o-stage△Utm- O Process△LoW pressure oxygen delignification technology. ATwo stage oxygen bleaching South China University of Technology
South China University of Technology Disadvantages of oxygen delignification ○ Lignin selectivity limitations ○ Installation cost ○ Creates need for extra recovery capacity New Development to Improve Effectiveness △Om Process △ Peroxide-aided single and double oxygen stages △Two oxygen addition points △Effect of matal ions △Lignin activation before O-stage △Ultim-O Process △Low pressure oxygen delignification technology △Two stage oxygen bleaching
a Summary of Oxygen delignification ◆ extension of pulping lignin removal currently at max of 50% Excessive lignin removal causes pulp strength loss CLess lignin entering bleach plant Decreases consumption of bleaching chemical South China University of Technology
South China University of Technology Summary of Oxygen delignification ◆extension of pulping ◆lignin removal currently at max. of 50% ◆excessive lignin removal causes pulp strength loss ◆Less lignin entering bleach plant ◆decreases consumption of bleaching chemical
Ozone Delignification Kappa number and brightness of softwood kraft pulp bleached in TCF sequence Sequence Kappa No Brightness, %SO OZ 9.9 66.7 OQP 7.1 71.1 OQPP 5.9 77.9 OZQP 3.6 775 OQPZ 2.7 77.6 OZQPP 2.8 83.9 OQPZP Not determined 89.9
Ozone Delignification Sequence Kappa No Brightness, %ISO OZ 9.9 66.7 OQP 7.1 71.1 OQPP 5.9 77.9 OZQP 3.6 77.5 OQPZ 2.7 77.6 OZQPP 2.8 83.9 OQPZP Not determined 89.9 Kappa number and brightness of softwood kraft pulp bleached in TCF sequence
Ozone Bleaching a Structure of Ozone Molecules: O3 O O South China University of Technology
South China University of Technology Ozone Bleaching Structure of Ozone Molecules: O3 - O- O . . . . . . . . . . . . . . . . . . . . . . . . O+ O- O- O+ O+ . . . . . . . . . . . . . . . . . . . . . . . . . . . . O+ O O O O O O O O O O O O