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The influence of dissolved wood components and sodium ion concentration on kraft pulping
KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
2004 (English)Licentiate thesis, comprehensive summary (Other academic)
Place, publisher, year, edition, pages
Stockholm: KTH Royal Institute of Technology, 2004. , 43 p.
Series
Trita-FPT-Report, ISSN 1652-2443
National Category
Polymer Technologies
Identifiers
URN: urn:nbn:se:kth:diva-90492OAI: oai:DiVA.org:kth-90492DiVA: diva2:506689
Presentation
(English)
Supervisors
Note
QC 20120302Available from: 2012-03-02 Created: 2012-02-24 Last updated: 2012-03-02Bibliographically approved
List of papers
1. Continuous Nano- and Ultrafiltration of Kraft Pulping Black Liquor with Ceramic Filters: A method for lowering the load on the recovery boiler while generating valuable side-products
Open this publication in new window or tab >>Continuous Nano- and Ultrafiltration of Kraft Pulping Black Liquor with Ceramic Filters: A method for lowering the load on the recovery boiler while generating valuable side-products
Show others...
2004 (English)In: Industrial crops and products (Print), ISSN 0926-6690, E-ISSN 1872-633X, Vol. 20, no 2, 143-150 p.Article in journal (Refereed) Published
Abstract [en]

Ceramic membranes coated with ZrO2 were used for the continuous separation of a well-defined low molecular weight lignin from softwood and hardwood kraft black liquors on a pilot scale. The membranes used had M-w cut-offs of 1000, 5000, and 15,000 Da, respectively. The flux (permeate flow) through the different membranes measured as L/(m(2 .)h) was studied by varying the inlet pressure and temperature. The black liquor lignins in the permeate from the filters were isolated and studied with GPC and UV spectroscopy. The low molecular weight lignin fraction was highly phenolic and could be polymerised by one-electron oxidation.

Keyword
black liquor, kraft pulping, lignin, recovery boiler, ultra-filtration
National Category
Paper, Pulp and Fiber Technology
Identifiers
urn:nbn:se:kth:diva-5431 (URN)10.1016/j.indcrop.2004.04.017 (DOI)000224636700004 ()2-s2.0-4644304536 (Scopus ID)
Note
QC 20100906Available from: 2006-03-08 Created: 2006-03-08 Last updated: 2017-11-21Bibliographically approved
2. The influence of industrial black liquor on the delignification rate in the kraft cooking
Open this publication in new window or tab >>The influence of industrial black liquor on the delignification rate in the kraft cooking
2007 (English)In: Journal of Pulp and Paper Science (JPPS), ISSN 0826-6220, Vol. 33, no 4, 240-245 p.Article in journal (Refereed) Published
Abstract [en]

The effect of dissolved wood components in industrial black liquor on the rate of delignification in softwood kraft cooking has been studied The results show that, when industrial black liquor was added, the delignification rate increased significantly during the bulk phase and decreased during the residual phase. A softwood black liquor was fractionated with ceramic membranes with various cut-offs, to see the way the addition of various molecular weight fractions of the black-liquor lignin affected the delignification rate. The results show that the delignification rate is dependent more on the content of phenolic groups than on the size of the lignin fragments. However, a low molecular-weight lignin fraction has a higher content of phenolic groups than a high molecular-weight fraction does. These results may explain one reason for the positive effect of adding industrial black liquor to the bulk phase of a softwood kraft cook.

Keyword
kraft pulping, delignification, black liquors, phenol groups
National Category
Paper, Pulp and Fiber Technology
Identifiers
urn:nbn:se:kth:diva-5433 (URN)000254544400009 ()2-s2.0-43049172002 (Scopus ID)
Note

Tidigare titel: The influence of industrial black liquor on the delignification rate in the kraft cook Uppdaterad från manuskript till artikel: 20100920 QC 20100920

Available from: 2006-03-08 Created: 2006-03-08 Last updated: 2017-11-21Bibliographically approved
3. The Effect of Sodium Ion Concentration and Dissolved Wood Components in the Kraft Cook of Softwood
Open this publication in new window or tab >>The Effect of Sodium Ion Concentration and Dissolved Wood Components in the Kraft Cook of Softwood
2004 (English)In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 19, no 3, 325-329 p.Article in journal (Refereed) Published
Abstract [en]

The effect of ionic strength and dissolved wood components (DWC) in form of industrial black liquor on the delignification rate and the brightness of the unbleached softwood kraft pulp has been investigated. A technique with a high liquor-to-wood ratio (75 L/kg) a so-called constant composition cook was used to separate the effects of the different parameters. The study showed that an increase in the ionic strength led to a decrease in the rate of delignification and gave a more coloured pulp, where as the presence of DWC gave a more coloured pulp and an increase in the delignification rate.

The influence of the ionic strength and DWC on the bleachability of the softwood kraft pulp in an ECF-sequence (D(EOP)DD) was also investigated. The results show that the bleachability i.e. consumption of bleaching chemicals to reach a certain brightness, was not affected by the ionic strength during the cook. The addition of DWC, on the other hand, increased the consumption of bleaching chemicals to reach ISO brightness 89%.

Keyword
kraft pulping, delignification rate, bleachability, softwood, black liquor
National Category
Paper, Pulp and Fiber Technology
Identifiers
urn:nbn:se:kth:diva-5432 (URN)000224636500007 ()2-s2.0-6344252669 (Scopus ID)
Note

QC 20141205

Available from: 2006-03-08 Created: 2006-03-08 Last updated: 2017-11-21Bibliographically approved

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Citation style
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