Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
The influence of alkali charge and temperature in the kraft cook on the QPQP bleachability and the kappa number composition of birch pulp
KTH, Superseded Departments, Pulp and Paper Technology.
2002 (English)In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 17, no 3, 206-212 p.Article in journal (Refereed) Published
Abstract [en]

The main objective of this investigation was to study how the alkali charge and the temperature in the kraft cook influence the QPQP bleachability of oxygen-delignified birch pulp. The bleachability was evaluated as the normalised consumption of bleaching chemicals required to reach a certain light absorption coefficient of the pulp. All the pulps had a kappa number of about 17 after the cook and a kappa number of about 10 after oxygen delignification. The alkali charge significantly affected the bleachability and the best bleachability was obtained for an intermediate level alkali charge ([HO-](initial)=1,35 mol/L, corresponding to an effective alkali charge of 21.6% on wood). An increase in cooking temperature gave only a slight increase in bleachability. The contributions to the kappa number of lignin, hexenuronic acids (HexA) and other non-lignin structures were also investigated. Lignin contributed to about 60% of the kappa number in pulps after the cook, to about 40% in pulps after the oxygen delignification, and to about 30% after QPQP bleaching. Hexenuronic acids contributed between 3.7 to 4.7 kappa number units in all pulps, which makes them the largest contributors to the kappa number in oxygen-delignified and QPQP bleached pulps. Other non-lignin structures, were contributing about 3 kappa number units in pulps after the cook, but decreased to less than I kappa number unit after QPQP bleaching. No great differences in the composition of the kappa number could be seen between pulps produced under different pulping conditions, except that there was a somewhat lower hexenuronic acid content in the pulps produced with the highest alkali charge or at the highest cooking temperature.

Place, publisher, year, edition, pages
2002. Vol. 17, no 3, 206-212 p.
Keyword [en]
Birch, Bleachability, Bleaching, Hardwood, Hexenuronic acids, Kraft pulping, Ox-dem kappa number, TCF, hexeneuronic acid groups, xylan
Identifiers
URN: urn:nbn:se:kth:diva-22003ISI: 000178894500001OAI: oai:DiVA.org:kth-22003DiVA: diva2:340701
Note
QC 20100525Available from: 2010-08-10 Created: 2010-08-10 Last updated: 2017-12-12Bibliographically approved

Open Access in DiVA

No full text

Search in DiVA

By author/editor
Ek, Monica
By organisation
Pulp and Paper Technology
In the same journal
Nordic Pulp & Paper Research Journal

Search outside of DiVA

GoogleGoogle Scholar

urn-nbn

Altmetric score

urn-nbn
Total: 94 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf