Search for dissertations about: "Bleaching"

Showing result 6 - 10 of 114 swedish dissertations containing the word Bleaching.

2. 6. Free radical mediated cellulose degradation

   Author : Erik Johansson; KTH; []
   Keywords : free radicals; cellulose; polymer; average chain length; bleaching; TCF; ozone; degradation;

   Abstract : This thesis addresses the mechanisms involved in cellulosedegradation in general and Totally Chlorine Free (TCF) bleachingof pulp in particular. The thesis shows that the cellulosedegradation during high consistency ozone bleaching is explainedby free radical chain reactions. READ MORE

4. 7. Influence of acid hydrogen peroxide treatment on refining energy and TMP properties

   Author : Karin Walter; Per Engstrand; Magnus Paulsson; Lennart Salmén; Mittuniversitetet; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TMP; Black Spruce; Energy reduction; Hydrogen peroxide; Ferrous sulphate; Refining; Inter-stage treatment; Pulp and paper properties; Fenton´s reagent; Bleaching; Sodium dithionite; Brightness; Metals; Fibre dimensions; Cross-sectional dimensions; Chemical composition; Cellulose and paper engineering; Cellulosa- och pappersteknik;

   Abstract : The potential of using acid hydrogen peroxide under Fenton conditions to lower the electrical energy consumed during the production of Black spruce (Picea mariana) thermomechanical pulp (TMP) was investigated. The chemical system, which consisted of ferrous sulphate, hydrogen peroxide and optionally an enhancer (3,4-dimethoxybenzyl alcohol, ethylenediaminetetraacetic acid or oxalic acid/sodium oxalate), was evaluated as an inter-stage treatment where the primary refiner was used as a mixer. READ MORE

5. 8. On the oxidation of kraft pulp - Formation of carbonyl groups during acidic hydrogen peroxide oxidation

   Author : Axel Martinsson; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; bleaching; Hydrogen Peroxide; wet-strength; cellulose oxidation;

   Abstract : A shift from fossil based to bio based raw material is necessary if the needs of a growing population are to be fulfilled sustainably. Today, the packaging industry is heavily dependent on products originating from fossil feedstocks. READ MORE

6. 9. Dietary fibre production from oat hulls

   Author : Eva Schmitz; Bioteknik; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Oat hulls; Dietary fibre; Chemical composition; Bleaching; Pre-treatment; Enzyme synergy;

   Abstract : The current threats of climate change connected to the unsustainable consumption of fossil resources paired with an increasing world population demands the exploration of alternative raw materials for the production of food, fuel and specialty chemicals. Agricultural waste streams present suitable sources due to their availability in large quantities at low costs without competing with current food production. READ MORE

7. 10. Xylan degradation by the thermophilic bacterium Rhodothermus marinus. Characterization and function of a thermostable xylanase

   Author : Eva Nordberg Karlsson; Bioteknik; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; fed-batch cultivation; kraft pulp; bleaching; glycosyl hydrolase family 10; recombinant xylanase; polysaccharide binding domain; Biotechnology; Bioteknik;

   Abstract : A gene encoding a multidomain xylanase from the thermophilic bacterium Rhodothermus marinus has been cloned, sequenced and produced in Escherichia coli . The gene product was found to be a 109 kDa protein consisting of five domains. READ MORE