Search for dissertations about: "Kappa number"

Showing result 1 - 5 of 125 swedish dissertations containing the words Kappa number.

  2. 1. Extended impregnation kraft cooking of softwood : Effects on reject, yield, pulping uniformity, and physical properties

    Author : Katarina Karlström; Mikael E. Lindström; Elisabet Brännvall; Kristofer Gamstedt; Anna Jacobs; KTH; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; high kappa number pulp; extended impregnation; softwood; spruce; picea abies; pine; pinus sylvestris; uniform delignification; kappa number distribution; reject; yield; tensile index; tensile stiffness index; SCT; starch multilayers; mechano-sorptive creep; hygroexpansion; dimensional stability; eucalypt; birch; acacia; Cellulose and paper engineering; Cellulosa- och pappersteknik;

    Abstract : Converting wood into paper is a complex process involving many different stages, one of which is pulping. Pulping involves liberating the wood fibres from each other, which can be done either chemically or mechanically. READ MORE

  4. 2. Aspects of extended impregnation kraft cooking for high-yield pulping of hardwood

    Author : Helena Wedin; Mikael E. Lindström; Martin Ragnar; Jorge L. Colodette; KTH; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Yield; pulp; kraft cook; carbohydrate; xylan; oxygen delignification; Hexenuronic acid; kappa number;

    Abstract : The long-term trend regarding wood is an increase in price. Because wood contributes to a large part of production costs, the efficient utilisation of wood is greatly desired to reduce production costs for kraft pulp producers. During the 1990s, the development of improved modified kraft cooking began, which led to higher yields. READ MORE

  5. 3. On the importance of oxidizable structures in bleached kraft pulps

    Author : Olena Sevastyanova; Göran Gellerstedt; Colodette Jorge; KTH; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; bleached pulps; betula; eucalyptus; 5-formyl-2furancarboxylic acid; 2-furancarboxylic acid; hexenuronic acid; kappa number; kraft pulps; oxidation equivalents; Cellulose and paper engineering; Cellulosa- och pappersteknik;

    Abstract : After cooking, kraft pulps always contain not only residual lignin but also significant amounts of hexenuronic acid and other non-lignin structures oxidizable by permanganate under the standard kappa number determination conditions. These here referred to as false lignin. READ MORE

  6. 4. The Impact of Dissolved Matter on Fiberline Processes

    Author : Caroline Wilke; Ulf Germgård; Niclas Andersson; Juha Fiskari; Karlstads universitet; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Bleach plant control; Carbonate; Carryover; Chlorine dioxide bleaching; COD; Dissolved lignin; Dissolved matter; Fiberline control; Filtrate; Hexenuronic acid; Hydrogen peroxide bleaching; Kappa number; Oxygen delignification; Wash loss; Chemical Engineering; Kemiteknik;

    Abstract : The impact of dissolved matter on the performance of four fiberline process stages was investigated: oxygen delignification, hot acid treatment, chlorine dioxide bleaching, and hydrogen peroxide reinforced alkaline extraction. In particular the impact on delignification due to dissolved lignin was studied. READ MORE

  7. 5. Optimization of Pretreatment of Kraft Pulp with Nitrogen Oxides

    Author : Urban Öjteg; Chalmers tekniska högskola; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Kappa number; lignins; Nitric acid; Magnesium; spent liquors; viscosity; softwood; oxygen bleaching; Nitrogen dioxide; Manganese; Oxygen; Nitrogen oxides; pretreatment; Kraft pulp;

    Abstract : Modified kraft pulp subjected to oxygen bleaching following pretreatment with 2% nitrogen dioxide for 140 min with the addition of oxygen resulted in low selectivity after subsequent oxygen bleaching. In contrast, pretreatment in the absence of oxygen removed more than 80% of the lignin after oxygen bleaching and still maintained high selectivity (kappa number less than 5 at viscosity 950 dm3/kg). READ MORE