Search for dissertations about: "Delignification"

Showing result 16 - 20 of 58 swedish dissertations containing the word Delignification.

  2. 16. Studies on the chemistry of delignification in alkaline media

    Author : Otto Lindeberg; Stockholms universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES;

    Abstract : Several questions concerning the structure of lignins in pulp (residual lignins) have not been resolved. It is not known whetherit is composed of lignin units originally present in the lignin and stable to the pulping conditions, or ifit contains structures formed by stabilization (side-reactions) of initially labile structures, or ifthere are stable bonds between the carbohydrates and the lignin, initially present and/or formed during the cook, or if4. READ MORE

  4. 17. 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. 18. 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

  6. 19. Oxygen-Alkali Treatment of Kraft Pulp and Cellobiitol. Model Experiments and Applied Studies of Interest for Oxygen Bleaching

    Author : Bengt Järrehult; Chalmers tekniska högskola; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; selectivity; pH-levels; copper; oxygen delignification; catalytic effects; iron; alkali; cellobiitol; magnesium; yield;

    Abstract : During oxygen delignification of kraft pulp the alkalinity has a decisive influence upon the selectivity, defined as viscosity at a given kappa number. Using 0.2% pulp consistency in order to achieve constant pH-levels a minimum selectivity was reached at pH 13, corresponding to 0.1 M NaOH. READ MORE

  7. 20. From recovery boiler to integration of a textile fiber plant : Combination of mass balance analysis and chemical engineering

    Author : Hans Magnusson; Ulf Germgård; Gunnar Henriksson; Hans Theliander; Karlstads universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; kraft pulping; recovery boiler; smelt properties; non-process elements; oxygen delignification; viscose manufacturing; integrated production; regenerated cellulose; sulfatmassa; fysikaliska egenskaper; smälta; sodapanna; processfrämmande ämnen; bioraffinaderi; integrerad produktion; regenererad cellulosa; Chemical Engineering; Kemiteknik;

    Abstract : Modern chemical technology is an efficient tool for solving problems, particularly within the complex environment of the pulp and paper industry, and the combination of experimental studies, mill data and mass balance calculations are of fundamental importance to the development of the industry. In this study various examples are presented, whereby chemical technology is of fundamental importance. READ MORE