METHOD FOR OXYGEN DELIGNIFICATION OF CELLULOSE PULP BY MIXING OF CHEMICALS

摘要

The invention relates to a method for the improved oxygen delignification of cellulose pulp with a medium consistency of 8-16 %. The fraction of dissolve d oxygen can be maintained at a high level throughout the process by the use o f high pressure, greater than 15.0 bar, and by repeated agitative mixing while maintaining the high pressure, such that as large a fraction as just over 20 % of the total oxygen added is dissolved in the fluid phase, and such that the amount of oxygen in the fluid phase is maintained at a high level throughout the complete high pressure section. This means that the amount of oxygen tha t is dissolved in the fluid phase and that penetrates the cellulose fibres can be maintained at an optimal high level throughout the process for improved delignification of the cellulose.