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Improvement of the retention-fromation relationship using three-component retention aid systems
KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Fibre Technology.
2012 (English)Doctoral thesis, comprehensive summary (Other academic)
Place, publisher, year, edition, pages
Stockholm: KTH Royal Institute of Technology, 2012. , 62 p.
Series
Trita-CHE-Report, ISSN 1654-1081 ; 2012:19
Keyword [en]
Dewatering, drag reduction, fibre flocculation, filler retention, fine paper, flow imaging, flow loop, formation aid, kraft pulp, magnetic resonance imaging, MRI, paper formation, pilot web former, pressure drop, retention aid, turbulence damping
National Category
Paper, Pulp and Fiber Technology
Identifiers
URN: urn:nbn:se:kth:diva-96259ISBN: 978-91-7501-314-5 (print)OAI: oai:DiVA.org:kth-96259DiVA: diva2:529920
Public defence
2012-06-08, K1, Teknikringen 56, KTH, Stockholm, 13:00 (English)
Opponent
Supervisors
Note
QC 20120530Available from: 2012-05-31 Created: 2012-05-31 Last updated: 2012-05-31Bibliographically approved
List of papers
1. A pilot web former designed to study retention-formation relationships
Open this publication in new window or tab >>A pilot web former designed to study retention-formation relationships
2010 (English)In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 25, no 2, 185-194 p.Article in journal (Refereed) Published
Abstract [en]

A pilot-scale fourdrinier former has been developed for the purpose of investigating the relationship between retention and paper formation (features, retention aids, dosage points, etc.). The main objective of this publication was to present the R-F (Retention and formation)-machine and demonstrate some of its fields of applications. For a fine paper stock (90% hardwood and 10% softwood) with addition of 25% Filler (based on total solids content), the relationship between retention and formation was investigated for a microparticulate retention aid (cationic polyacrylamide together with anionic montmorillonite clay). The retention-formation relationship of the retention aid system was investigated after choosing standardized machine operating conditions (e.g. the jet-to-wire speed ratio). As expected, the formation was impaired when the retention was increased. Since good reproducibility was attained, the R-F (Retention and formation)-machine was found to be a useful tool for studying the relationship between retention and paper formation.

Keyword
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-96256 (URN)000279341100007 ()
Note
QC 20120530Available from: 2012-05-31 Created: 2012-05-31 Last updated: 2017-12-07Bibliographically 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, E-ISSN 2000-0669, 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: 2017-12-14Bibliographically approved
3. Improvement of the retention-formation relationship using three-component retention aid systems
Open this publication in new window or tab >>Improvement of the retention-formation relationship using three-component retention aid systems
2012 (English)In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 27, no 1, 86-92 p.Article in journal (Refereed) Published
Abstract [en]

The effects of retention on formation and drainage by using three-component retention aid systems were examined using a pilot web former. The purpose was to examine whether the relationship between retention and formation could be improved by using systems based on cationic Polyacrylamide, structurally different high molecular weight anionic polymers and montmorillonite clay. The structure of the anionic polymer was varied from linear to fully crosslinked and added from a small amount up to such a level where papermaking fibres in suspension become dispersed. The pilot web former experiments were performed using an R-F (Retention and Formation)-machine employing a fine paper stock (90% hardwood and 10% softwood kraft pulp) with an addition of 25% precipitated calcium carbonate (PCC) (based on total solids content). It was found that the paper formation could be significantly improved, at a given level of retention by using a micro-particulate retention aid system (cationic Polyacrylamide and montmorillonite clay) in combination with an anionic Polyacrylamide. Most important, it was found, that with such three-component systems, the impairment of the drainage could be avoided and, hence, that the improved formation was not provided by worsened drainage on the wire section.

Keyword
Drainage, Filler, Fine paper, Formation, Formation aid, Fourdrinier former, Kraft pulp, Retention, Retention agent
National Category
Paper, Pulp and Fiber Technology
Identifiers
urn:nbn:se:kth:diva-96257 (URN)
Note
QC 20120531Available from: 2012-05-31 Created: 2012-05-31 Last updated: 2017-12-07Bibliographically approved
4. The effects of formation aids on flow properties of cellulosic fibrous suspensions
Open this publication in new window or tab >>The effects of formation aids on flow properties of cellulosic fibrous suspensions
Show others...
(English)Manuscript (preprint) (Other academic)
Abstract [en]

The effects of high molecular weight anionic polymers on the flow behaviour of fibrous suspensions were studied using phase flow encoded nuclear magnetic resonance imaging (MRI). We examined whether formation improvements by high molecular weight polymers correlate with turbulence damping. Flow imaging measurements and pressure drop analysis were performed for water and fibrous suspensions (0.5 % consistency) with and without polymer added, at different mean velocities (1.0, 1.2 and 1.4 m/s). Our results are consistent with drag reduction of turbulent flows by additives. The results further show how fibres and high molecular weight anionic polymers reduce the drag of turbulent flows, in terms of damping turbulence fluctuations (as determined by signal intensities) and flow profile characteristics. The turbulence damping effect was also manifested through a decrease of pressure drop. When fibres and polymers were used together, we found that the drag was reduced by amounts greater than the sum of the two independent effects. The reinforced effect on drag reduction can be explained by the fact that fibres and polymers act differently with the turbulent flow. The study also reveals the influence of the polymer structure (from linear to highly structured). The overall results indicate that turbulence damping and paper formation improvements by the addition of high molecular weight polymers (Class II formation aids) are strongly correlated. This work can lead to better specification of retention aid systems and design of modern head boxes used for papermaking.

Keyword
Drag reduction, Fibrous suspension, Formation aids, Flow imaging, High molecular weight polymer, MRI, Nuclear magnetic resonance imaging, Paper formation, Pressure drop, Turbulence damping, Velocity profiles
National Category
Paper, Pulp and Fiber Technology
Identifiers
urn:nbn:se:kth:diva-96258 (URN)
Available from: 2012-05-31 Created: 2012-05-31 Last updated: 2012-05-31Bibliographically approved

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Citation style
  • apa
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  • de-DE
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Output format
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