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Temperature and effective alkali effect on brown pulp kraft cooking

Authors
  • Favaro, Jaqueline Silveira Comelato1
  • Ventorim, Gustavo1
  • de Oliveira, Iliane Rodrigues2
  • de Oliveira, Cláudia Rodrigues1
  • 1 Universidade Júlio de Mesquita Filho (Unesp) – Campus Experimental de Itapeva, Brazil , (Brazil)
  • 2 Universidade Júlio de Mesquita Filho (Unesp) – Campus Experimental de Itapeva, Avenida José Bilesk, 90 – Jardim Maringá , (Brazil)
Type
Published Article
Journal
Nordic Pulp & Paper Research Journal
Publisher
De Gruyter
Publication Date
Apr 10, 2021
Volume
36
Issue
2
Pages
227–233
Identifiers
DOI: 10.1515/npprj-2020-0085
Source
De Gruyter
Keywords
Disciplines
  • Chemical pulping
License
Yellow

Abstract

One way to obtain high quality pulp production is to improve selectivity delignification of step, maximize yield. Brown pulp yield and chemical composition were studied, with variation of temperature and effective alkali in Kraft cooking. Considering that these variables directly affect lignin removal rate and final product quality. Industrial wood chips from Eucalyptus grandis x Eucalyptus urophylla hybrids were used in this study. The cooking was performed to obtain pulps with kappa number 13, 15 and 17 for temperatures 155 °C, 160 °C and 165 °C, using the same Factor H (695). Yields were analyzed according to: total yield, rejects content and screened pulp yield. Klason lignin content, wood and pulp sugars, levels of hexenuronic acids in pulp were also determined. Results indicate that lower cooking temperatures are beneficial in relation to cooking performance, selectivity and preservation of xylans. With a screened pulp yield of 57.1 % for KN 17 at the lowest temperature 155 ºC and 55.3 % at the same KN at 165 ºC. The lowest screened pulp yield obtained, 51 %, was for KN 13 at 165 ºC, with 54.1 % with the same KN at 155 ºC. Evidencing a decreasing linear trend of screened pulp yield with temperature increase and kappa number reduction.

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