Sökning: "kraft pulps"

Visar resultat 6 - 10 av 57 avhandlingar innehållade orden kraft pulps.

  1. 6. 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

  3. 7. Acid-base properties of and metal ion affinity for oxygen-delignified kraft pulps

    Författare :Karin Athley; KTH; []
    Nyckelord :Oxygen-delignified kraft pulps; Carboxylate groups; Potentiometric titration; Acid base properties; Constant capacitance model; Metal ion dsitribution; Surface complexes; Complex formation; Donnan theory;

    Sammanfattning : .... LÄS MER

  4. 8. Carbohydrate degradation and dissolution during Kraft cooking : Modelling of kinetic results

    Författare :Dan Johansson; Ulf Germgård; Pedro Fardim; Karlstads universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Kraft cooking; softwood; hardwood; cellulose; xylan; glucomannan; degradation; dissolution; Chemical engineering; Kemiteknik; Chemical Engineering; Kemiteknik;

    Sammanfattning : Chemical pulp fibres from wood are commonly used in products associated with packaging as well as with printing and writing. The prevalent way of liberating fibres is by subjecting wood chips to Kraft cooking. This process has a history of almost 130 years and should be both well described and well established. LÄS MER

  5. 9. Cation adsorption properties of substituted kraft fibres : an experimental and thermodynamic modelling study

    Författare :Ola Sundman; Lars-Olof Öhman; Per Persson; Janne Laine; Umeå universitet; []
    Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Kraft fibres; Donnan equilibria; ion exchange; acid base properties; potentiometric titrations; thermodynamic modelling; NPEs; GaAl12 7 ; EXAFS; Chemistry; Kemi;

    Sammanfattning : Acid/base and metal ion adsorption properties have been investigated for a range of chemically modified bleached Kraft fibre materials (pulps). The studies were performed via potentiometric titrations, Flame Atomic Absorbtion (and Emission) Spectroscopy, Inductively Coupled Plasma Optical Emission Spectroscopy and Extended X-ray Absorbtion Fine Structure measurements. LÄS MER

  7. 10. 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