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Applicability evaluation of a novel mullen restorer chemical for fluff pulp
2001 (English)Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
Abstract [en]

A mullen restorer chemical is used in the production of fluff pulp to facilitate the transition between treated fluff grades (treated with debonding agents) and untreated grades. It restores the pulp so it regains its strength and absorption properties by neutralizing the remaining debonding agent (Berocell 509 HA) in the white water system, and thus minimizing the size of the transition roll. This intermediate state, with a gradually reduced cationic content varies from one mill to another depending on the size of the white water system. The understanding of mullen restorer chemicals is not very extensive, partly due to the short history of these chemicals and the poor knowledge of the mechanism involved. This thesis, which has been performed at Eka Chemicals in Rollsbo Gothenburg, was aiming to compare and examine the possibility of replacing their current mullen restorer (Berocell 570) with a less harmful one, which also is more easy to handle (called Chemical A). This report looks at application evaluations (dosage and interaction time studies) of chemical A. Investigations regarding its charge nature, properties and capacity under certain process conditions have also been conducted in order to improve the understanding of this chemical. The tests have focused on studies to neutralize the debonding agent in the white water system as well as the restoration of broke. Laboratory instruments like Magendans and PCD (particle charge detector) have been used to provide an understanding of the charge nature of this chemical but also to obtain guidance to dosage levels needed to neutralize the quaternary amine in an aqueous solution. Treated and untreated pulp sheets were produced using two different laboratory sheetformers and physical properties like: mullen burst strength, wettability (wicking rate- and capacity), static potential and defiberization energy were tested and evaluated. The dosages and interaction times are thoroughly investigated and determined and these studies showed that it is better to replace the current mullen restorer chemical with the new one. It has been concluded that Chemical A forms a neutral inactive complex together with the cationic debonder, when both are present in the white water system. The restorance of broke is also possible, although a much longer interaction time is needed to neutralize the debonder, which is due to an increase in surface area preventing the contact between Chemical A and the debonder. Factors, such as a very complex structure and an inexplicable particle charge change caused by temperature- and salt additions set limitation to the understanding of Chemical A’s behaviour.

Place, publisher, year, edition, pages
2001.
Keywords [en]
Technology, Debonder, Mullen restorer chemical, Fluff pulp
Keywords [sv]
Teknik
Identifiers
URN: urn:nbn:se:ltu:diva-43305ISRN: LTU-EX--01/265--SELocal ID: 12ed7ff4-0845-4196-8a70-e0c1b8ddad53OAI: oai:DiVA.org:ltu-43305DiVA, id: diva2:1016536
Subject / course
Student thesis, at least 30 credits
Educational program
Chemical Engineering, master's level
Examiners
Note
Validerat; 20101217 (root)Available from: 2016-10-04 Created: 2016-10-04Bibliographically approved

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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
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