Search for dissertations about: "acid sulfite pulping"

Showing result 1 - 5 of 6 swedish dissertations containing the words acid sulfite pulping.

2. 1. The initial phase of sodium sulfite pulping of softwood : A comparison of different pulping options

   Author : Raghu Deshpande; Ulf Germgård; Pedro Fardim; Karlstads universitet; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Activation energy; acid sulfite pulping; bisulfite pulping; cellulose; delignification; dissolving pulp; extractives; glucomannan; hemicelluloses; lignin; lignin condensation; lignin carbohydrate complexes; pine; spruce; thiosulfate; total SO2; xylan; Chemical Engineering; Kemiteknik;

   Abstract : Single stage and two-stage sodium sulfite cooking were carried out on either spruce, pine or pure pine heartwood chips to investigate the influence of several process parameters on the initial phase of such a cook down to about 60 % pulp yield. The cooking experiments were carried out in the laboratory with either a lab-prepared or a mill-prepared cooking acid and the temperature and time were varied. READ MORE

4. 2. Wood chips for kraft and sulfite pulping : evaluation of novel forest-industrial drum-chipping technology

   Author : Jessica Gard Timmerfors; Leif J. Jönsson; David Blomberg; Sören Östlund; Umeå universitet; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; wood chip; drum chipper; impregnation; pulping; sulfite process; kraft process; Scots pine; Norway spruce; heartwood; frozen wood; moisture content;

   Abstract : Wood chipping and the supply of high-quality wood chips are of critical importance for most forest-industrial processes. The quality of wood chips affects product yield, product quality, and processability. READ MORE

5. 3. The initial phase of the sodium bisulfite pulping of softwood dissolving pulp

   Author : Raghu Deshpande; Ulf Germgård; Martin Ragnar; Karlstads universitet; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Activation energy; bisulfite pulping; cellulose; delignification; extractives; glucomannan; hemicelluloses; lignin; pine; spruce; thiosulfate; total SO2; xylan; Chemical Engineering; Kemiteknik;

   Abstract : The sulfite pulping process is today practised in only a small number of pulp mills around the globe and the number of sulfite mills that use sodium as the base (cation) is less than five. However, due to the increasing interest in the wood based biorefinery concept, the benefits of sulfite pulping and especially the sodium based variety, has recently gained a lot of interest. READ MORE

6. 4. Industrial applications and properties of oxalate-degrading enzymes

   Author : Sandra Winestrand; Leif J. Jönsson; Thomas Nilsson; Nils-Olof Nilvebrant; Gudmundur O. Hreggvidsson; Karlstads universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Oxalic acid; oxalate oxidase; oxalate decarboxylase; calcium oxalate; scaling; active packaging; Kemi; Chemistry;

   Abstract : Oxalate-degrading enzymes were investigated with focus on potential applications in the pulp and paper industry and in active packaging. Changes introduced to make the pulp and paper industry more environmentally friendly, such as recirculation of process-water streams and elementary chlorine free bleaching of pulp, have led to increasing problems with precipitation of calcium oxalate. READ MORE

7. 5. Lignin polysaccharide networks in softwood and chemical pulps : characterisation, structure and reactivity

   Author : Martin Lawoko; Göran Gellerstedt; Gösta Brunow; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Cellulose and paper engineering; Cellulosa- och pappersteknik;

   Abstract : The chemical interactions between the main wood components i.e., cellulose, hemicelluloses and lignin are of fundamental importance for understanding the chemical aspects of wood formation and its reactivity during fibre processing e.g during chemical pulping of wood. READ MORE