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Valuation of retention/formation relationships using a laboratory piot-paper machine
KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
2007 (English)Licentiate thesis, comprehensive summary (Other scientific)
Abstract [en]

The interdependency between filler retention and paper formation is well-known, where a high retention is accompanied by impaired formation. A challenge for today’s papermakers is to increase the competitiveness for uncoated and coated fine paper, by improving the formation at the same level of retention.

Over the years, the use and the demands of retention aids have increased as a consequence of a higher system closure, increased machine speeds and increased filler content. The knowledge of whether some retention aid systems are more or less detrimental to paper formation than other systems, is very limited. The insuffiency of knowledge is, however, also true for other chemical, mechanical and interacting factors, which influence the retention/formation relationship in a complex manner.

In order to investigate the retention/formation relationship (features, retention aids, dosage points, etc.), a pilot-scale fourdrinier former (R/F-machine) has been developed. The R/F-machine provides a short circulation of the white water and controlled experimental conditions and is appropriate for cost-effective investigations. Moreover, the R/F-machine has been designed to have a short residence time to chemical equilibrium and the machine has also shown high reproducibility in the results.

This licentiate thesis presents the R/F-machine and examines, during constant experimental conditions, the retention/formation relationships for some different retention aid systems. Three single-component cationic polyacrylamides with varying molecular weights and two polyacrylamide-based microparticulate systems with varying microparticles were examined. The retention aid systems were investigated on the R/F-machine, for a fine paper stock (90 % bleached hardwood and 10 % bleached softwood) with addition of 25 % filler (based on total solids content).

The results showed that the retention/formation relationship was not dependent on the retention aid system used. All systems showed the same relationship between retention and formation. On the other hand, the various retention aid systems provided different effects considering their retention performance.

Place, publisher, year, edition, pages
Stockholm: KTH , 2007. , 41 p.
Series
Trita-CHE-Report, ISSN 1654-1081 ; 2007:59
National Category
Paper, Pulp and Fiber Technology
Identifiers
URN: urn:nbn:se:kth:diva-4517OAI: oai:DiVA.org:kth-4517DiVA: diva2:12643
Presentation
2007-10-05, Sundbladssalen, STFI, KTH, Drottning Kristinas väg 61, Stockholm, 14:00
Opponent
Supervisors
Note
QC 20101118Available from: 2007-11-06 Created: 2007-11-06 Last updated: 2010-11-18Bibliographically approved
List of papers
1. A pilot-paper machine designed to the study retention/formation relationships
Open this publication in new window or tab >>A pilot-paper machine designed to the study retention/formation relationships
(English)In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669Article in journal (Other academic) Submitted
National Category
Paper, Pulp and Fiber Technology
Identifiers
urn:nbn:se:kth:diva-7573 (URN)
Note

QC 20100617

Available from: 2007-11-06 Created: 2007-11-06 Last updated: 2016-12-12Bibliographically approved
2. The effect of various retention aids on retention and formation
Open this publication in new window or tab >>The effect of various retention aids on retention and formation
2010 (English)In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, Vol. 25, no 2, 195-203 p.Article in journal (Refereed) Published
Abstract [en]

The interdependency between retention and paper formation was studied using a previously designed R-F (Retention and formation)-machine. The objective of the work was to investigate the retention-formation relationship for different types of retention aid systems. Both single-component cationic polyacrylamides with varying molecular weights and polyacrylamide-based microparticulate retention aids were investigated on the R-F-machine, for a fine paper stock with addition of 25% filler (based on total solids content). Results showed that the retention-formation relationship was not dependent on the retention aid systems used, since all systems provided similar relationships. In terms of the retention performance, significant differences were observed, depending on the choice of microparticle system and molecular weight of the used cationic polyacrylamide.

Keyword
Drainage, Flocculation, Formation, Fourdrinier former, Kraft pulp, Pilot study, Polyacrylamide, Retention, Retention agent
National Category
Paper, Pulp and Fiber Technology
Identifiers
urn:nbn:se:kth:diva-7574 (URN)000279341100008 ()
Note
QC 20100617 Uppdaterad från submitted till published(20101118)Available from: 2007-11-06 Created: 2007-11-06 Last updated: 2012-05-31Bibliographically approved

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