Progress Towards 'Best in Class' : A Summary of Bleaching Chemical Consumption Reduction and Optimization

摘要

Beginning in 2004, Catalyst Paper's, Elk Falls Division began a program to achieve "Best-in-Class" bleaching chemical consumption for its softwood fibre line. This paper describes steps taken to: 1. Improve brownstock washing; 2. Eliminate hydrogen peroxide in the Eop stage and decrease hydrogen peroxide in E2p stage; 3. Decrease NaOH associated with hydrogen peroxide use; 4. Improve mixing in the Dl stage; 5. Improve washing on Eo stages; and 6. Decrease carryover to the Dl stage. As a result of these actions, the mill has achieved significant progress towards "Best-in-Class": 1. NaOH use decreased by 3kg/Odt unbleached; 2. H_2O_2 use decreased 4.4 kg/Odt unbleached; 3. C1O_2 decreased 10 kg/Odt unbleached; and 4. Dl steam usage decreased and 5. The cost of bleaching-decreased by approximately $12 Cdn per bleached Adt when compared at the same unbleached kappa number of 26.