Sökning: "Ulf Germgård"

Visar resultat 11 - 15 av 15 avhandlingar innehållade orden Ulf Germgård.

1. 11. Modifying kraft pulping to produce a softwood pulp requiring less energy in tissue paper production

   Författare :Hafizur Rahman; Per Engstrand; Mikael E. Lindström; Louise Logenius; Peter Sandström; Ulf Germgård; Mittuniversitetet; []
   Nyckelord :Modifying kraft pulp; tissue dewatering; polysulfide; sodium borohydride; tensile index; hemicellulose;

   Sammanfattning : Modification of softwood kraft pulp by the addition of either polysulfide (PS) or sodium borohydride (NaBH4) has been shown to increase the pulp yield due to a higher retention of glucomannan.  The pulps with higher yield gave a paper with higher tensile index than reference pulp, especially at lower degrees of refining. LÄS MER

3. 12. Experimental study of alkalinisation of cellulose in industrial relevant conditions

   Författare :Diana Carolina Reyes Forsberg; Ola Sundman; Bertil Eliasson; Ulf Germgård; Umeå universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; Mercerisation; Alkalinisation; Cellulose I; Cellulose II; Alkali cellulose; Viscose; Cellulose ether; Carboxymethylcellulose; Sodium glycolate; Sodium diglycolate; Raman spectroscopy;

   Sammanfattning : Mercerisation of cellulose pulp with a solution of NaOH is the first step of manufacturing cellulose-based value-added products, e.g. viscose fibres and cellulose ethers. During this process, cellulose transforms into a swollen crystalline structure, alkali cellulose (Na-Cell). LÄS MER

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

   Författare :Caroline Wilke; Ulf Germgård; Niclas Andersson; Juha Fiskari; Karlstads universitet; []
   Nyckelord :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;

   Sammanfattning : 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. LÄS MER

5. 14. Fibre surface properties of kraft pulp : The influence of wood raw material, bleaching and storage

   Författare :Gerd Wäne; Ulf Germgård; Pedro Fardim; Karlstads universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Chemical Engineering; Kemiteknik;

   Sammanfattning : The aim of this thesis was to study the fibre surface properties of Birch (Betula ssp.), Eucalyptus (E. urograndis and E. globulus) and Spruce (Picea Abies) pulps bleached using two different methods: ECF (Elementary Chlorine Free) and TCF (Totally Chlorine Free). LÄS MER

7. 15. Some Aspects on Pulp Pre-treatment Prior to Viscose Preparation

   Författare :Linda Östberg; Ulf Germgård; Gunnar Henriksson; Karlstads universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Chemical Engineering; Kemiteknik;

   Sammanfattning : Large amounts of carbon disulphide are consumed in the conventional production of viscose. Until a novel, eco-friendly, wood-based process for the production of cellulose textile fibres has been developed and implemented, it is important to try to find ways to improve the conventional viscose process, e.g. LÄS MER