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  • 1.
    Almlöf Ambjörnsson, Heléne
    et al.
    Karlstad University, Faculty of Technology and Science, Department of Chemical Engineering.
    Germgård, Ulf
    Karlstad University, Faculty of Technology and Science, Department of Chemical Engineering.
    Enzyme treatment of dissolving pulps as a way to improve the following dissolution of the fibres2012Conference paper (Other academic)
  • 2.
    Almlöf Ambjörnsson, Heléne
    et al.
    Karlstad University, Faculty of Technology and Science, Department of Chemical Engineering.
    Germgård, Ulf
    Karlstad University, Faculty of Technology and Science, Department of Chemical Engineering.
    Extended Mercerization Prior to Carboxymethyl Cellulose Preparation2011Conference paper (Other (popular science, discussion, etc.))
  • 3.
    Almlöf Ambjörnsson, Heléne
    et al.
    Karlstad University, Faculty of Technology and Science, Department of Chemical Engineering.
    Germgård, Ulf
    Karlstad University, Faculty of Technology and Science, Department of Chemical Engineering.
    Jardeby, Kristina
    Borregaard Chemcell, Sarpsborg, Norge.
    Kreutz, Björn
    Borregaard Chemcell, Sarpsborg, Norge.
    The influence of mercerization on the degree of substitution in carboxymethyl cellulose2009Conference paper (Other (popular science, discussion, etc.))
  • 4.
    Almlöf Ambjörnsson, Heléne
    et al.
    Karlstad University, Faculty of Technology and Science, Department of Chemical Engineering.
    Schenzel, Karla
    Marthin-Luther University Halle-Wittenberg.
    Germgård, Ulf
    Karlstad University, Faculty of Technology and Science, Department of Chemical Engineering.
    Characterization of CMC by NIR FT Raman spectroscopy2012Conference paper (Other (popular science, discussion, etc.))
  • 5.
    Almlöf Ambjörnsson, Heléne
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Östberg, Linda
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Schenzel, Karla
    Martin Luther University Halle-Wittenberg, Department of Natural Scinence III, Institute of Agriculture and Nutritional Science.
    Larsson, Per Tomas
    Innventia AB, Fibre and Material Science Business area Biorefining, Stockholm.
    Germgård, Ulf
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Enzyme pretreatment of dissolving pulp as a way to improve the following dissolution in NaOH/ZnO2014In: Holzforschung, ISSN 0018-3830, E-ISSN 1437-434X, Vol. 68, no 4, p. 385-391Article in journal (Refereed)
  • 6.
    Almlöf, Heléne
    et al.
    Karlstad University, Faculty of Technology and Science, Department of Chemical Engineering.
    Basta, Jiri
    Karlstad University, Faculty of Technology and Science, Department of Chemical Engineering.
    Germgård, Ulf
    Karlstad University, Faculty of Technology and Science, Department of Chemical Engineering.
    Guo, Sanchuan
    Heijnesson-Hulten, Anette
    The Effect of Stock Storage on The Quality of Bamboo Kraft Pulp2010In: O PAPEL, ISSN 0031-1057, Vol. 72, no 6, p. 43-53Article in journal (Refereed)
  • 7.
    Almlöf, Heléne
    et al.
    Karlstad University, Faculty of Technology and Science, Department of Chemical Engineering.
    Kreutz, Bjørn
    Borregaard Chemcell, Norway.
    Jardeby, Kristina
    Borregaard Chemcell, Norway.
    Germgård, Ulf
    Karlstad University, Faculty of Technology and Science, Department of Chemical Engineering.
    The influence of extended mercerization on some properties of carboxymethyl cellulose (CMC)2012In: Holzforschung, ISSN 0018-3830, E-ISSN 1437-434X, Vol. 66, p. 21-27Article in journal (Refereed)
    Abstract [en]

    Carboxymethyl cellulose (CMC) is produced commercially in a two stage process consisting of a mercerization stage in which the pulp is treated with alkali in a water alcohol solution and a second etherification stage whereby monochloro-acetic acid is added to the pulp slurry. In this study, the influence of the conditions of an extended mercerization stage was evaluated on the etherification stage concerning the degree of substitution (DS) and the filterability of the resulting CMC. The parameters studied were: (1) the ratio of cellulose I and cellulose II in the original pulp, (2) the concentration of alkali, (3) the temperature and (4) the retention time in the mercerization stage. The DS results indicate that the NaOH concentration in the mercerization stage is the most important among the parameters studied. When the NaOH concentration in the mercerization stage was high (27.5%), cellulose II showed a lower reactivity than cellulose I with respect to the DS obtained in the resulting CMC. The results from the filtration ability of CMC water solutions are interpreted that the amount of cellulose II in the original pulp and the temperature has a negative influence, while the NaOH concentration in the mercerization stage has a positive influence on the filtration ability. Retention time between 1 h–48 h in the mercerization stage had no effect on the DS or the filtration value. The filtration ability was assumed to be highly influenced by the presence of poorly reacted cellulose segments. The CMC samples with the lowest filtration ability at a given DS can be assumed to have the highest degree of unevenly substituted segments.

  • 8.
    Almlöf, Heléne
    et al.
    Karlstad University, Faculty of Technology and Science, Department of Chemical Engineering.
    Schenzel, Karla
    Department of Natural Science III, Institute of Agriculture and Nutritional Science, Martin Luther University, Germany.
    Germgård, Ulf
    Karlstad University, Faculty of Technology and Science, Department of Chemical Engineering.
    Carboxymethyl cellulose produced at different mercerization conditions and characterized by NIR FT Raman spectroscopy and chemometric methods2013In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 8, no 2, p. 1918-1932Article in journal (Refereed)
  • 9.
    Andersson, N.
    et al.
    BTG Instruments AB, Box 602, Säffle.
    Wilke, Caroline
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Germgård, Ulf
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Impact of dissolved lignin in peroxide bleaching2017In: PEERS Conference 2017: Maximizing Success Through Innovation, TAPPI Press , 2017, p. 597-604Conference paper (Refereed)
    Abstract [en]

    It has been demonstrated in previous studies that dissolved lignin carryover has a significant impact in oxygen delignification and chlorine dioxide stages. Specifically for chlorine dioxide stages, it has been shown that the total kappa number of the pulp, i.e. the sum of the fiber kappa number and the filtrate kappa number, corresponds very well to its bleach demand and should be used for accurate feedforward based control. Since peroxide also is commonly used for pulp bleaching, and gaining in popularity, the present study was conducted in order to investigate the basic relations and mechanisms, using laboratory peroxide bleaching experiments comparing different carryover lignin concentrations and types. The results show that in particular chlorine dioxide filtrates have significant negative impact on delignification and brightening, likely due to alkali consumption of e.g. dissolved lignin, and that compensation using a higher alkali charge will result in lower brightness at a given kappa number. The paper also touches upon the opportunities using advanced process control systems for bleach plants, and the process and economic improvements which can be made by properly accounting for disturbances such as carryover variability.

  • 10. Andersson, Niclas
    et al.
    Germgård, Ulf
    Karlstad University, Faculty of Technology and Science, Department of Chemical Engineering.
    Johansson, Kristina
    Ljungqvist, Carl-Henrik
    Thuvander, Fredrik
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Paper Surface Centre. Karlstad University, Faculty of Technology and Science, Materials Science. Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Engineering.
    Determining the strain to failure for constrained pulp fibres by means of single-fibre2002In: Appita Journal, Vol. vol 55 no 3Article in journal (Refereed)
  • 11. Andersson, Niclas
    et al.
    Germgård, Ulf
    Karlstad University, Faculty of Technology and Science, Department of Chemical Engineering.
    Johansson, Kristina
    Ljungqvist, Carl-Henrik
    Thuvander, Fredrik
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Paper Surface Centre. Karlstad University, Faculty of Technology and Science, Materials Science. Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Engineering.
    Determining the strain to failure for constrained pulp fibres by means of single-fibre fragmentation2002In: Appita Journal 55(2002)3, 224-229Article in journal (Refereed)
  • 12.
    Andersson, Niclas
    et al.
    BTG Process Solutions, Sweden.
    Wilke, Caroline
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013). BTG Process Solutions, Sweden.
    Akhlesh, Mathur
    BTG Process Solutions, Singapore.
    Smith, Dan
    BTG Process Solutions, USA.
    Germgård, Ulf
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Measurement of Dissolved Lignin, and its Impact in Fiberline Unit Operations2017Conference paper (Refereed)
  • 13.
    Andersson, Niclas
    et al.
    BTG Instruments AB, Saffle, Sweden..
    Wilke, Caroline
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Biazzo, Tom
    BTG Instruments AB, Saffle, Sweden..
    Van Fleet, Rick
    BTG Instruments AB, Saffle, Sweden..
    Germgård, Ulf
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    A new sensor and a novel control concept for optimized fiber line operation2014In: TAPPI Journal, ISSN 0734-1415, Vol. 13, no 10, p. 39-45Article in journal (Refereed)
    Abstract [en]

    Kraft and sulfite pulp mills use several consecutive process stages for pulp production. However, usually only one key pulp parameter is used for process control and that is the lignin content in the fibers, typically expressed as the kappa number. Even so, to improve process efficiency, more variables need to be monitored. To do that, a new sensor was developed, the dissolved lignin transmitter (DLT), along with a new control concept. The DLT measures the dissolved lignin content in the pulp slurry using a unique principle based on optical measurements. The device can measure the dissolved lignin inline at low consistency and at medium consistency. The sensor has two major applications: 1) improving the efficiency in washing stages and 2) optimizing chemical charges. Results from several mill trials have shown that the contribution from dissolved lignin in the filtrate portion of the pulp is up to 30% of the total bleach load, i.e., fiber and filtrate kappa number combined into the bleach plant. Hence, chemical savings can be achieved taking this component into account compared to only measuring the washed fiber kappa number. Application: The results of this study can help mills understand how to better control the pulping stages, which might lead to significant economic savings and better pollution control.

  • 14.
    Andersson, Niclas
    et al.
    BTG Instruments AB.
    Wilke, Caroline
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013). BTG Instruments AB.
    Biazzo, Tom
    BTG Americas Inc. .
    van Fleet, Rick
    BTG Americas Inc. .
    Germgård, Ulf
    Karlstad University, Faculty of Technology and Science, Department of Chemical Engineering.
    A new sensor and a novel control concept for optimized fiberline operation2013In: 2013 PEERS Conference, Co-located with the 2013 International Bioenergy and Bioproducts Conference, TAPPI Press, 2013, p. 190-215Conference paper (Refereed)
  • 15.
    Andersson, Niclas
    et al.
    BTG Instruments.
    Wilke, Caroline
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences. BTG Instruments.
    Biazzo, Tom
    BTG Americas Inc.
    Van Fleet, Rick
    BTG Americas Inc..
    Germgård, Ulf
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Beder-Miller, Sandra
    BTG Americas Inc..
    Is Conductivity the Best Measurement of Bleach Plant Carryover?2015In: Pulp & paper Canada, ISSN 0316-4004, p. 1-6Article in journal (Refereed)
  • 16. Andersson, Niclas
    et al.
    Wilson, David
    Germgård, Ulf
    Karlstad University, Faculty of Technology and Science, Department of Chemical Engineering.
    An improved kinetic model structure for softwood kraft cooking2003In: Nordic Pulp and Paper Research Journal, Vol. vol 18 no 2Article in journal (Refereed)
  • 17. Andersson, Niclas
    et al.
    Wilson, David
    Germgård, Ulf
    Karlstad University, Faculty of Technology and Science, Department of Chemical Engineering.
    Model based kraft cooking optimisation2003In: Nordic Pulp and Paper Research Journal, Vol. vol 18 no 4Article in journal (Refereed)
  • 18. Andersson, Niclas
    et al.
    Wilson, David
    Germgård, Ulf
    Karlstad University, Faculty of Technology and Science, Department of Chemical Engineering.
    Using validated continuous kraft digester models for profile optimisation2002Conference paper (Refereed)
  • 19. Andersson, Niclas
    et al.
    Wilson, David
    Germgård, Ulf
    Karlstad University, Faculty of Technology and Science, Department of Chemical Engineering.
    Validating continuous kraft digester kinetic models with online NIR measurements2002Conference paper (Refereed)
  • 20. Andersson, Niclas
    et al.
    Wilson, David
    Germgård, Ulf
    Karlstad University, Faculty of Technology and Science, Department of Chemical Engineering.
    Lindström, Tomas
    Organic matter content in black liquor inside and outside chips during kraft cooking2001In: Paperi ja Puu, Vol. vol 83 no 7Article in journal (Refereed)
  • 21.
    Annergren, Goran
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Germgård, Ulf
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Process aspects for sulfite pulping2014In: Appita journal, ISSN 1038-6807, ISSN 1038-6807, Vol. 67, no 4, p. 270-276Article in journal (Refereed)
    Abstract [en]

    Sulfite pulping of wood, with the aim of producing a paper product, can be carried out under acidic, neutral or alkaline conditions. However, if a dissolving pulp is required to be achieved, only acidic conditions may be employed. The main reason for this specific requirement for dissolving pulps is the high level of cellulose purity required. The hemicellulose content should therefore be low and hemicellulose molecules are best removed at low pH. Another difference is that in paper pulps it is the fibre properties that are of a dominant interest, while in a dissolving pulp the cellulose properties are of significant interest. However, one similarity for both paper and dissolving sulfite pulps is the risk of uncontrolled side-reactions, which can lead to severe lignin condensation reactions, and in extreme cases even to a totally black pulp. Thus, sulfite pulping is a relatively complex chemical process and an overview of the most important parameters is thus presented.

  • 22. Annergren, Göran
    et al.
    Germgård, Ulf
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Sulfate cooking - a commercially dominating and continously improving pulping process2014Report (Other academic)
    Abstract [en]

    Sulfite cooking was earlier the dominating pulping process but sulfate (kraft) cooking is today the most important process for the production of chemical pulps and high-yield pulps. One important reason for this development of the sulfate process is its ability to efficiently use different wood species, in particular different hardwood species. Another reason is that bleached hardwood sulfate pulps have become a strong competitor to bleached softwood sulfite pulps. The pros and cons of sulfate cooking are discussed in this report and compared with sulfite cooking.

     

    Download full text (pdf)
    Sulfate_cooking
  • 23. Beder- Miller, Sandra
    et al.
    Andersson, Niclas
    Wilke, Caroline
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Biazzo, Tom
    van Fleet, Rick
    Germgård, Ulf
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Is Conductivity the Best Measurement of Bleach Plant Carryover?2014Conference paper (Refereed)
  • 24. Björklund, Magnus
    et al.
    Germgård, Ulf
    Karlstad University, Faculty of Technology and Science, Department of Chemical Engineering.
    Basta, Jiri
    Effect of cooking conditions on ECF bleaching and brightness reversion of birch kraft pulp2005In: Tappi JournalArticle in journal (Refereed)
  • 25. Björklund, Magnus
    et al.
    Germgård, Ulf
    Karlstad University, Faculty of Technology and Science, Department of Chemical Engineering.
    Basta, Jiri
    Formation of AOX and OCI in ECF-bleaching of birch pulp2004In: Tappi Journal 3(2004)8, 7-11Article in journal (Refereed)
  • 26. Björklund, Magnus
    et al.
    Germgård, Ulf
    Karlstad University, Faculty of Technology and Science, Department of Chemical Engineering.
    Basta, Jiri
    Formation of AOX and OCl in ECF-bleaching of birch pulp2004In: Tappi Journal, Vol. vol 3 no 8Article in journal (Refereed)
  • 27. Björklund, Magnus
    et al.
    Germgård, Ulf
    Karlstad University, Faculty of Technology and Science, Department of Chemical Engineering.
    Basta, Jiri
    The influence of softwood kraft cooking conditions on the brightness development in ECF- bleaching2004In: Appita Journal, Vol. vol 57 no 3Article in journal (Refereed)
  • 28. Björklund, Magnus
    et al.
    Germgård, Ulf
    Karlstad University, Faculty of Technology and Science, Department of Chemical Engineering.
    Basta, Jiri
    The influence of softwood kraft cooking conditions on the brightness development in ECF- bleaching2003Conference paper (Refereed)
  • 29. Björklund, Magnus
    et al.
    Germgård, Ulf
    Karlstad University, Faculty of Technology and Science, Department of Chemical Engineering.
    Jour, Pia
    Forsström, Ann-Britt
    AOX formation in ECF bleaching at different kappa numbers ' influence of oxygen delignification and hexenuronic acid content2001Conference paper (Refereed)
  • 30. Björklund, Magnus
    et al.
    Germgård, Ulf
    Karlstad University, Faculty of Technology and Science, Department of Chemical Engineering.
    Jour, Pia
    Forsström, Ann-Britt
    AOX formation in ECF bleaching at different kappa numbers: Influence of oxygen delignification and hexenuronic acid content2002In: Tappi Journal, 1(2002)7, 20-24, Vol. vol 1 no 7Article in journal (Refereed)
    Abstract [en]

    he aim of this study was to determine how oxygen delignification before bleaching and the hexenuronic acid (HexA) content of the pulps influenced the acisorbable organic halogen (AOX) formation in the elemental chlorine free (ECP) bleaching effluent. Softwood industrial chips cooked to different kappa numbers were oxygen defignified, treated in a hot acid stage (A*), or not pretreated at all before ECF bleaching. We compared the AOX levels in the ECF effluents from bleaching of these pulps. There was a higher formation of AOX for oxygen delignified pulps than for non-oxygen delignified pulps compared at the same kappa number before ECF bleaching. The hexenuronic acid (HexA) content of the pulps had a major impact on the AOX levels in the D[0] effluent. The oxygen delignified pulps had a higher HexA content than the non-oxygen delignified pulps compared at the same kappa number. This explains the higher AOX formation from oxygen delignified pulps. The AOX originating from HexA was not stable upon storage. Application, This study gives additional insight on the AOX formation in ECF bleaching. The information may be used to take appropriate measures when addressing environmental issues

  • 31. Björklund, Magnus
    et al.
    Germgård, Ulf
    Karlstad University, Faculty of Technology and Science, Department of Chemical Engineering.
    Jour, Pia
    Forsström, AnnBritt
    TCF and ECF bleaching effluent COD at varying kappa numbers after cooking2003In: Appita Journal, Vol. vol 56 no 3Article in journal (Refereed)
  • 32. Björklund, Magnus
    et al.
    Germgård, Ulf
    Karlstad University, Faculty of Technology and Science, Department of Chemical Engineering.
    Jour, Pia
    Forsström, AnnBritt
    TCF and ECF bleaching effluent COD at varying kappa numbers after cooking2003In: Appita Journal 56(2003)3, 200-205Article in journal (Refereed)
  • 33.
    Boudreau, Jonna
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Germgård, Ulf
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Influence of Various Pulp Properties on the Adhesion Between Tissue Paper and Yankee Cylinder Surface2014In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 9, no 2, p. 2107-2114Article, review/survey (Refereed)
    Abstract [en]

    The strength of the adhesion between the paper and the drying Yankee cylinder is of great importance with respect to the final properties of a tissue paper product. Therefore, the effects of a few potentially important pulp properties have been evaluated in laboratory experiments. Four highly different kraft pulps were used, and the adhesion strength was measured by means of the force required when scraping off a paper from a metal surface with a specifically designed knife mounted on a moving cart. The adhesion strength was observed to increase with increasing grammage and increasing degree of beating of the pulp. It was also found that pulpscontainingmore fines, or with higher hemicellulose content, gave rise to higher adhesion strength.

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    fulltext
  • 34. De Magistris, F.
    et al.
    Germgård, Ulf
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Beghello, Luciano
    Järnström, Lars
    Karlstad University, Faculty of Technology and Science, Department of Chemical Engineering. Karlstad University, Faculty of Technology and Science, Paper Surface Centre.
    Lestelius, Magnus
    Karlstad University, Faculty of Technology and Science, Department of Chemical Engineering. Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences, Paper Surface Centre.
    Influence of paper compressibility on flexographic printing quality2008In: Progress in paper physics seminar 2008, proceedings, Espoo, Finland, 2-5 June 2008 / [ed] Kotomaki K, Koivunen K, Paulapuro H,, 2008, p. 243-245Conference paper (Other (popular science, discussion, etc.))
    Abstract [en]

    The compression ability of fibres and fibre networks were investigated. The surface and bulk compressions of paper influence calendering, coating, surface sizing ability and the penetration of ink in printing. Two kraft pulps (spruce) were produced in the laboratory to obtain pulps with different levels of xylan. Using those kraft pulps alone or mixed with 50% of a commercial TMP pulp, single-layer sheets were formed in a Formette Dynamique sheet former. The pulps and mixture levels were chosen to obtain papers with systematically altered property variation but with constant grammage. The papers were characterized according to both bulk and surface compressibility. The papers were printed in a flexo IGTF1 laboratory printing press and the transferred amount of ink, dot gain, and mottling were analyzed.

  • 35.
    De Magistris, Federica
    et al.
    Karlstad University, Faculty of Technology and Science, Department of Chemical Engineering. Karlstad University, Faculty of Technology and Science, Department of Energy, Environmental and Building Technology.
    Germgård, Ulf
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Beghello, Luciano
    Karlstad University, Faculty of Technology and Science, Department of Chemical Engineering. Karlstad University, Faculty of Technology and Science, Paper Surface Centre.
    Järnström, Lars
    Karlstad University, Faculty of Technology and Science, Department of Chemical Engineering. Karlstad University, Faculty of Technology and Science, Paper Surface Centre. Karlstad University, Faculty of Technology and Science, Materials Science.
    Lestelius, Magnus
    Karlstad University, Faculty of Technology and Science, Department of Chemical Engineering. Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences, Paper Surface Centre. Karlstad University, Faculty of Technology and Science, Materials Science.
    Effect of calendering on the compressibility of papers made with fibre of various properties2010Conference paper (Other (popular science, discussion, etc.))
    Abstract [en]

    The surface and bulk compressibility of a given paper influence its calendering, coating, surface sizing and printing properties. This study aims at a deeper knowledge of which variable affects the compressibility of paper sheets and how calendering effect different sheet properties. The pulps were characterized by their chemical compositions and physical properties. The bulk compressibility, the surface compressibility and the thickness were evaluated both before and after calendering

  • 36.
    De Magistris, Federica
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Germgård, Ulf
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Beghello, Luciano
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Järnström, Lars
    Karlstad University, Faculty of Technology and Science, Department of Chemical Engineering. Karlstad University, Faculty of Technology and Science, Paper Surface Centre.
    Lestelius, Magnus
    Karlstad University, Faculty of Technology and Science, Department of Chemical Engineering. Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences, Paper Surface Centre.
    Influence of Fibre Characteristics of the Surface Roughness of Paper and on Flexographic Print Quality2010Conference paper (Refereed)
  • 37. De Magistris, Federica
    et al.
    Germgård, Ulf
    Karlstad University, Faculty of Technology and Science, Department of Chemical Engineering.
    Svedinger-Andersson, Maria
    Pulping to different xylan contents and its impact on the pulp quality2008Conference paper (Other (popular science, discussion, etc.))
  • 38.
    Deshpande, Raghu
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Germgård, Ulf
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Grundberg, Hans
    Domsjö Fabriker AB, Örnsköldsvik, Sweden.
    Sundvall, Lars
    MoRe Research, Örnsköldsvik, Sweden.
    Giummarella, Nicola
    Wallenberg Wood Science Center, School of Chemical Science and Engeneering, Royal Institute of Technology, KTH, 100 44, Stockholm, Sweden.
    Henriksson, Gunnar
    Wallenberg Wood Science Center, School of Chemical Science and Engeneering, Royal Institute of Technology, KTH, 100 44, Stockholm, Sweden.
    Lawoko, Martin
    Wallenberg Wood Science Center, School of Chemical Science and Engeneering, Royal Institute of Technology, KTH, 100 44, Stockholm, Sweden.
    The Reactivity of Lignin Carbohydrate Complex (LCC) During Manufacture of Dissolving Sulphite Pulp from Softwood2018In: Industrial crops and products (Print), ISSN 0926-6690, E-ISSN 1872-633X, p. 315-322Article in journal (Refereed)
  • 39.
    Deshpande, Raghu
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Germgård, Ulf
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Sundvall, Lars
    MoRe Research Örnsköldsvik.
    Grundberg, Hans
    Domsjö Fabriker Örnsköldsvik.
    Some process aspects on acid sulphite pulping of softwood2016In: Journal of Science & Technology for Forest Products and Processes, ISSN 1927-6311, E-ISSN 1927-632X, Vol. 6, no 2, p. 48-54Article in journal (Refereed)
  • 40.
    Deshpande, Raghu
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Germgård, Ulf
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Sundvall, Lars
    MoRe Research, Örnsköldsvik, Sweden.
    Grundberg, Hans
    Domsjö Fabriker AB, Örnsköldsvik, Sweden.
    The Initial Phase of Sodium Bisulfite Pulping of Pine, Part II2016In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 31, no 3, p. 379-385Article in journal (Refereed)
    Abstract [en]

    Single stage sodium bisulfite cooking of pine was carried out to investigate the influence of time and temperature in the initial phase of the cook. The cooking experiments were carried out using either a lab or a mill prepared cooking acid and the initial stage of the cook was extended up to 5 h cooking time. The impact of temperature on wood components and side reactions was analyzed between 142°C and 165°C. Arrhenius equation was used to determine the influence of temperature on wood components during the initial phase of bisulfite cooking and the activation energy was calculated for delignification rate, cellulose degradation and hemicellulose dissolution with regard to glucomannan and xylan. The extent of extractives removal at different temperature and time was also analyzed.

  • 41.
    Deshpande, Raghu
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Sundvall, Lars
    MoRe Research.
    Grundberg, Hans
    Domsjö Fabriker.
    Germgård, Ulf
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    New findings in sulfite pulping of softwood dissolving pulps2015In: 5th Avancell Conference Chalmers University of Technology  Gothenburg Sweden, October 6-7 2015, 2015Conference paper (Other academic)
    Abstract [en]

    Karlstads University has for a long time done research on sulfite pulping with the purpose to increase the knowledge on sulfite pulping, to verify old fundamental results an to keep the knowledge on sulfite pulping alive. The basic objective during the last years has been to increase the value of the products produced in such a process and the vision is to make sulfite pulps the preferred pulp grade for dissolving pulps. These studies have so far included spruce and pine. Domsjö Fabriker and MoRe Research in Örnsköldsvik, Sweden have been industry partners in this project.

  • 42.
    Deshpande, Raghu
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Sundvall, Lars
    MoRe Research.
    Grundberg, Hans
    Domsjö.
    Germgård, Ulf
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Some process aspects on single-stage bisulfite pulping of pine2016In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 31, no 3, p. 379-385Article in journal (Refereed)
    Abstract [en]

    Sulfite pulping of pine is well-known to be a risky process because problematic lignin conden-sation reactions can occur resulting in poor pulp quality. However, sulfite pulping of pine is interesting of economic reasons as pine wood is cheaper than spruce. Therefore it has become interesting to investigate sulfite pulping again to determine if old data are still valid. Thus sodium bisulfite pulping of pine was carried out to investigate the influence of time, temperature and cooking acid quality. A small comparison of spruce pulping was also included. By using different cooking temperatures the activation energies for delignification and for degradation of cellulose and hemicelluloses could be determined. The results showed no lignin condensation reactions, thus it was not problematic to carry out these pine cooking experiments. It was found that glucomannan had higher activation energy than xylan and the activation energies of these hemicelluloses were lower than the corresponding value for the lignin degradation. It was found that the activation energy for bisulfite pulping of pine was slightly lower than the activation energy for bisulfite pulping of spruce.

  • 43.
    Deshpande, Raghu
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Sundvall, Lars
    MoRe Research, Örnsköldsvik, Sweden.
    Grundberg, Hans
    Domsjö Fabriker, Örnsköldsvik, Sweden.
    Germgård, Ulf
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    The influence of different types of bisulfite cooking liquors on pine wood components2016In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 11, no 3, p. 5961-5973Article in journal (Refereed)
    Abstract [en]

    Single stage sodium bisulfite cooking of pine was carried out to study the initial phase of the bisulfite cook and the experiments were carried out using either a lab or a mill prepared cooking acid. The chemical consumption, the pH profile and the pulp yield with respect to cellulose, lignin, glucomannan, xylan and extractives were investigated. The pulp composition with respect to carbohydrates and lignin content was summarized in a kinetic model. The initial phase of the bisulfite cook was extended to 5 h cooking time down to a final pulp yield of about 60 %. The side reactions with respect to thiosulfate and sulfate formation were investigated continuously in all experiments. The cooking temperature used in these experiments was 154 °C.

  • 44.
    Deshpande, Raghu
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Sundvall, Lars
    MoRe research.
    Grundberg, Hans
    Domsjö.
    Germgård, Ulf
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    The influence of the temperature on the initial phase of sodium bisulfite pulping of spruce2015In: O Papel, ISSN 0031-1057, Vol. 76, no 4, p. 56-61Article in journal (Refereed)
  • 45.
    Deshpande, Raghu
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Sundvall, Lars
    MoRe Research Örnsköldsvik.
    Grundberg, Hans
    Domsjö Fabriker Örnsköldsvik.
    Germgård, Ulf
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    The Initial Phase of Sodium Bisulfite Pulping of Spruce: Part 12016In: Cellulose Chemistry and Technology, ISSN 0576-9787, Vol. 50, no 2, p. 293-300Article in journal (Refereed)
  • 46.
    Deshpande, Raghu
    et al.
    MoRe Research, Domsjö Fabriker, Karlstads universitet.
    Sundvall, Lars
    MoRe Research.
    Grundberg, Hans
    Domsjö Fabriker.
    Germgård, Ulf
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    The magic of sulphite pulping: The critical first stage of a dissolving pulp cook2013Conference paper (Other academic)
    Abstract [en]

    A PhD project was started in 2012 with the purpose to in depth examine the first and second part of a sodium sulfite dissolving pulp cook including a following extraction stage. The experimental study started with the first part of the cook when using spruce or pine as the wood raw material and when using lab or mill cooking liquors. A large number of cooking experiments have been performed and a lot of data has been obtained and the risk for obtaining a black cook has been especially observed. In the latter case the thiosulphate content is very critical as it can both lead to a black cook and to decomposition reactions in the cooking liquor. How to avoid problematic cooking conditions will be especially highlighted in the project but ways to produce new pulp grades and new chemicals will be equally important

  • 47.
    Germgård, Ulf
    Karlstad University, Faculty of Technology and Science, Department of Chemical Engineering.
    Aspects on the reactivity of dissolving pulps prior to viscose preparation2012Conference paper (Other academic)
  • 48.
    Germgård, Ulf
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Aspects on the reactivity of pulps prior to viscose preparation2012In: Abstracts of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 243Article in journal (Other academic)
  • 49.
    Germgård, Ulf
    Karlstad University, Faculty of Technology and Science, Department of Chemical Engineering.
    Bleaching of pulp2004In: The Ljungberg Textbook in Pulp Technology, KTH Stockholm, Sweden 2004, ISSN 1652-2443, 2004Chapter in book (Other academic)
  • 50.
    Germgård, Ulf
    Karlstad University, Faculty of Technology and Science, Department of Chemical Engineering.
    Chlorite Delignification Simplifies Characterization of Chemical Pulps2010Conference paper (Refereed)
1234 1 - 50 of 176
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