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1. 1. Some aspects on TCF-bleachability of softwood alkaline pulps

   Författare :Karin Sjöström; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Bleachability; chlorine-free bleaching; softwoods; kraft pulps; alkaline sulfite pulps; oxygen; hydrogen peroxide; ozone; hydrogen sulfide ion; hydroxide ion; temperature; sodium ion.; Cellulose and paper engineering; Cellulosa- och pappersteknik;

   Sammanfattning : The bleachability of softwood oxygen delignified pulps has been studied, i.e. the ease (requirement of bleaching chemicals) with which the pulps can be brightened to a target brightness in totally chlorine free (TCF) bleaching stages, including hydrogen peroxide, ozone and chelating agent stages. LÄS MER

3. 2. Kraft Pulp Fibre Surfaces. Chemical Composition and Effect on Pulp Bleachability

   Författare :Anette Heijnesson Hultén; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Ray cells; carbohydrates; Kraft pulps; enzymes; lignin; fibre surfaces; metal ions; bleachability;

   Sammanfattning : The work presented in this thesis concerns studies of kraft fibre surfaces in respect of chemical composition and effect on pulp bleachability. Kraft fibre surfaces were studied by mechanical peeling using a disintegrator operated at 20.000-200.000 revolutions and a pulp consistency of 3% or 4. LÄS MER

4. 3. On the bleachability of alkaline pulps. The influence of residual lignin structure

   Författare :Waleed Wafa Al-Dajani; KTH; []
   Nyckelord :B-O-4; bleachability; hexenuronic acid; hydrogen peroxide; hydrosulfide ion; hydroxyl ion; ionic strength; residual lignin.;

   Sammanfattning : .... LÄS MER

5. 4. On the Process Development of an ECF Light Bleaching Sequence for the Production of High Quality Softwood Kraft Pulp and Low AOX Formation

   Författare :Sara Starrsjö; Juha Fiskari; Mikael Lindström; Olena Sevastyanova; Maria Boman; Peter Sandström; Mittuniversitetet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Chemical Engineering; Natural Science; Chemical Pulping; Softwood; Kraft Pulp; Bleaching; ECF light bleaching; Chlorine Dioxide; AOX formation; Delignification; Bleachability;

   Sammanfattning : The aim of this work is to contribute to the process development of the ECF light bleaching sequence Q(OP)D(PO) by providing a better understanding of the bleaching of softwood kraft pulp. There are few published studies on this type of sequence, and more knowledge is needed on how to reduce environmental impact, improve cost-effectiveness and ensure a high pulp quality. LÄS MER

7. 5. On the Interrelation Between Kraft Cooking Conditions and Pulp Composition

   Författare :Catrin Gustavsson; Mikael E. Lindström; Jorge Colodette; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Delignification; Kraft pulping; Residual phase lignin; Hydroxide; Hydrogen sulphide ion; Ionic strength; Temperature; Bleachability; Hexenuronic acid; Carbohydrates; Cellulose and paper engineering; Cellulosa- och pappersteknik;

   Sammanfattning : In the early 1990’s, a lot of work was focused on extending the kraft cook to a low lignin content (low kappa number). The driving force was the need to further reduce the environmental impact of the bleaching, as less delignification work would be needed there. LÄS MER