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Johansson, Dan
Publications (10 of 10) Show all publications
Johansson, D. & Germgård, U. (2008). A kinetic study of softwood Kraft cooking: carbohydrate dissolution as a function of cooking conditions. Appita journal, 61(3), 229-234
Open this publication in new window or tab >>A kinetic study of softwood Kraft cooking: carbohydrate dissolution as a function of cooking conditions
2008 (English)In: Appita journal, ISSN 1038-6807, Vol. 61, no 3, p. 229-234Article in journal (Refereed) Published
National Category
Chemical Engineering
Research subject
Chemical Engineering
Identifiers
urn:nbn:se:kau:diva-2043 (URN)
Available from: 2008-05-21 Created: 2008-05-21 Last updated: 2017-12-07Bibliographically approved
Johansson, D. & Germgård, U. (2008). A Kinetic Study of Softwood Kraft Cooking: Carbohydrate Dissolution as a Function of the Cooking Conditions. Appita Journal, 61(2008)3,228-233
Open this publication in new window or tab >>A Kinetic Study of Softwood Kraft Cooking: Carbohydrate Dissolution as a Function of the Cooking Conditions
2008 (English)In: Appita Journal, Vol. 61(2008)3,228-233Article in journal (Refereed)
National Category
Chemical Engineering
Research subject
Chemical Engineering
Identifiers
urn:nbn:se:kau:diva-16564 (URN)
Available from: 2013-01-21 Created: 2013-01-21 Last updated: 2013-01-21
Johansson, D. (2008). Carbohydrate degradation and dissolution. (Licentiate dissertation).
Open this publication in new window or tab >>Carbohydrate degradation and dissolution
2008 (English)Licentiate thesis, monograph (Other academic)
Series
Karlstad University Studies 2008:12, ISSN 14038099
National Category
Chemical Engineering
Research subject
Chemical Engineering
Identifiers
urn:nbn:se:kau:diva-17573 (URN)9789170631702 (ISBN)
Available from: 2013-01-21 Created: 2013-01-21 Last updated: 2013-01-21
Johansson, D. (2008). Carbohydrate degradation and dissolution during Kraft cooking: Modelling of kinetic results. (Licentiate dissertation). Karlstad: Karlstad University
Open this publication in new window or tab >>Carbohydrate degradation and dissolution during Kraft cooking: Modelling of kinetic results
2008 (English)Licentiate thesis, comprehensive summary (Other scientific)
Abstract [en]

Chemical pulp fibres from wood are commonly used in products associated with packaging as well as with printing and writing. The prevalent way of liberating fibres is by subjecting wood chips to Kraft cooking. This process has a history of almost 130 years and should be both well described and well established. However, new products and new applications that use fibres as an important renewable resource make it all the more important that the properties of fibres be controllable. The properties of wood fibres are influenced by their carbohydrate composition which, in turn, is dependent on the cooking conditions used. This thesis studies the degradation and dissolution of the different carbohydrates during Kraft cooking and summarizes the results in kinetic expressions.

Industrial wood chips from Norway spruce (Picea abies) were cooked at a high liquor-to-wood ratio in an autoclave digester at varying concentrations of hydroxide ions, hydrogen sulphide ions and sodium ions as well as varying temperatures. The pulps were analysed for carbohydrate composition, kappa number, content of hexenuronic acid and the pure cellulose viscosity, i.e. only the cellulose content in the pulp sample was used for calculating the viscosity. Kraft cooking of Eucalyptus urophylla and Eucalyptus grandis was also studied, using industrial liquor-to-wood ratios, to examine the relationship between hexenuronic acids and the amount of xylan in the pulp samples.

For Kraft cooking of Norway spruce it was found that an increase in the concentration of hydroxide ions increased the rate of dissolution of the carbohydrates and the degradation of the cellulose degree of polymerization (DP). However, measured at a kappa number of 30, it is seen that a low hydroxide ion concentration can lower the carbohydrate yield and the pure cellulose viscosity dramatically. The hydroxide ion concentration not only affects the rate of dissolution but also the amount of xylan that reacts in the slower, final phase. Both cellulose and hemicelluloses were found to be affected by the hydrogen sulphide ion concentration. The dissolution of cellulose and hemicelluloses at varying sodium ion concentrations was found to be affected in different directions. The effect of sodium ion concentration on the DP was found to be dependent on the method of evaluation. The pulp viscosity was found to be affected twice as much by the sodium ion concentration than the pure cellulose viscosity was. For Kraft cooking of hardwood it was found that a high xylan yield not always is synonymous with a high hexenuronic acids content.

Place, publisher, year, edition, pages
Karlstad: Karlstad University, 2008. p. 48
Series
Karlstad University Studies, ISSN 1403-8099 ; 2008:12
Keywords
Kraft cooking, softwood, hardwood, cellulose, xylan, glucomannan, degradation, dissolution
National Category
Chemical Engineering
Research subject
Chemical Engineering
Identifiers
urn:nbn:se:kau:diva-1626 (URN)978-91-7063-170-2 (ISBN)
Presentation
2008-04-25, Ericssonsalen, 9C 204, Karlstads universitet, Karlstad, 13:00
Opponent
Supervisors
Available from: 2008-05-21 Created: 2008-05-21 Last updated: 2011-11-24
Johansson, D. & Germgård, U. (2008). Carbohydrate degradation during softwood Kraft cooking: influence on cellulose viscosity, carbohydrate composition and hexenuronic acid content. Nordic Pulp & Paper Research Journal, 23(3), 292-298
Open this publication in new window or tab >>Carbohydrate degradation during softwood Kraft cooking: influence on cellulose viscosity, carbohydrate composition and hexenuronic acid content
2008 (English)In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 23, no 3, p. 292-298Article in journal (Refereed) Published
Abstract [en]

A kinetic model, including the variables temperature as well as hydroxide ion, sulphide ion and sodium ion concentrations, was fitted to laboratory data from kraft cooking of industrial Norway spruce chips. The model described well the data for carbohydrates, for hexenuronic acids and for the intrinsic viscosity. 

National Category
Chemical Engineering
Research subject
Chemical Engineering
Identifiers
urn:nbn:se:kau:diva-2044 (URN)10.3183/NPPRJ-2008-23-03-p292-298 (DOI)
Available from: 2008-05-21 Created: 2008-05-21 Last updated: 2017-12-07Bibliographically approved
Greschik, T., Guo, S., Basta, J., Germgård, U. & Johansson, D. (2008). Optimization of the cooking conditions when producing high quality eucalyptus pulps using a design of experiments (DoE) approach. Paper presented at Second Workshop on Chemical Pulping Processes at Karlstad University, Karlstad, Sweden, November 18-19, 2008. Paper presented at Second Workshop on Chemical Pulping Processes at Karlstad University, Karlstad, Sweden, November 18-19, 2008.
Open this publication in new window or tab >>Optimization of the cooking conditions when producing high quality eucalyptus pulps using a design of experiments (DoE) approach
Show others...
2008 (English)Conference paper, Published paper (Other (popular science, discussion, etc.))
National Category
Chemical Engineering
Research subject
Chemical Engineering
Identifiers
urn:nbn:se:kau:diva-22144 (URN)
Conference
Second Workshop on Chemical Pulping Processes at Karlstad University, Karlstad, Sweden, November 18-19, 2008
Available from: 2013-01-21 Created: 2013-01-21 Last updated: 2013-01-21
Johansson, D. & Germgård, U. (2006). A kinetic model describing the carbohydrate dissolution during softwood kraft cooking. Paper presented at First Workshop on Chemical Pulping Processes, Karlstad University, Karlstad, Sweden, November 14-15, 2006. Paper presented at First Workshop on Chemical Pulping Processes, Karlstad University, Karlstad, Sweden, November 14-15, 2006.
Open this publication in new window or tab >>A kinetic model describing the carbohydrate dissolution during softwood kraft cooking
2006 (English)Conference paper, Published paper (Other (popular science, discussion, etc.))
National Category
Chemical Engineering
Research subject
Chemical Engineering
Identifiers
urn:nbn:se:kau:diva-16563 (URN)
Conference
First Workshop on Chemical Pulping Processes, Karlstad University, Karlstad, Sweden, November 14-15, 2006
Available from: 2013-01-21 Created: 2013-01-21 Last updated: 2013-01-21
Johansson, D. & Germgård, U. (2006). A kinetic study of softwood kraft cooking- carbohydrate dissolution as a function of the cooking conditions. Paper presented at 2006 Engineering, Pulping and Environmental Conference in Atlanta, USA, November 6-8, 2006. Paper presented at 2006 Engineering, Pulping and Environmental Conference in Atlanta, USA, November 6-8, 2006.
Open this publication in new window or tab >>A kinetic study of softwood kraft cooking- carbohydrate dissolution as a function of the cooking conditions
2006 (English)Conference paper, Published paper (Refereed)
National Category
Chemical Engineering
Research subject
Chemical Engineering
Identifiers
urn:nbn:se:kau:diva-16565 (URN)
Conference
2006 Engineering, Pulping and Environmental Conference in Atlanta, USA, November 6-8, 2006
Available from: 2013-01-21 Created: 2013-01-21 Last updated: 2013-01-21
Johansson, D. & Germgård, U. (2006). The Relationship Between Xylan and Hexenuronic Acid in Eucalyptus Kraft Pulping. O Papel, 67(2006)10,84-91
Open this publication in new window or tab >>The Relationship Between Xylan and Hexenuronic Acid in Eucalyptus Kraft Pulping
2006 (English)In: O Papel, Vol. 67(2006)10,84-91Article in journal (Refereed)
National Category
Chemical Engineering
Research subject
Chemical Engineering
Identifiers
urn:nbn:se:kau:diva-24720 (URN)
Available from: 2013-01-22 Created: 2013-01-22 Last updated: 2013-01-22
Germgård, U. & Johansson, D. (2005). Kinetik för utlösning av cellulosa och hemicellulosa under sulfatkok (Kinetics and dissolution of cellulose and hemicellulose during kraft cooking). Paper presented at PTF Spring Meeting. Paper presented at PTF Spring Meeting.
Open this publication in new window or tab >>Kinetik för utlösning av cellulosa och hemicellulosa under sulfatkok (Kinetics and dissolution of cellulose and hemicellulose during kraft cooking)
2005 (Swedish)Conference paper, Published paper (Other (popular science, discussion, etc.))
National Category
Chemical Engineering
Research subject
Chemical Engineering
Identifiers
urn:nbn:se:kau:diva-20736 (URN)
Conference
PTF Spring Meeting
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Distrubution: Via KaU

Available from: 2013-01-21 Created: 2013-01-21 Last updated: 2013-01-21
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