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Karlström, A., Johansson, L. & Hill, J. (2019). On the modeling of tensile index from larger data sets. Nordic Pulp & Paper Research Journal
Open this publication in new window or tab >>On the modeling of tensile index from larger data sets
2019 (English)In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669Article in journal (Refereed) Epub ahead of print
Abstract [en]

The objective of this study is to analyze and foresee potential outliers in pulp and handsheet properties for larger data sets. The method is divided into two parts comprising a generalized Extreme Studentized Deviate (ESD) procedure for laboratory data followed by an analysis of the findings using a multivariable model based on internal variables (i. e. process variables like consistency and fiber residence time inside the refiner) as predictors. The process data used in this has been obtained from CD-82 refiners and from a laboratory test program perspective, the test series were extensive. In the procedure more than 290 samples were analyzed to get a stable outlier detection. Note, this set was obtained from pulp at one specific operating condition. When comparing such "secured data sets" with process data it is shown that an extended procedure must be performed to get data sets which cover different operating points. Here 100 pulp samples at different process conditions were analyzed. It is shown that only about 60 percent of all tensile index measurements were accepted in the procedure which indicates the need to oversample when performing extensive trials to get reliable pulp and handsheet properties in TMP and CTMP processes.

Place, publisher, year, edition, pages
De Gruyter Open Ltd, 2019
Keywords
CTMP, energy efficiency, fiber residence time, modeling, pulp and handsheet properties, pulp consistency, temperature profile, tensile index, TMP, Models, Pulp refining, Software testing, Statistics, Handsheet properties, Residence time, Temperature profiles, Thermomechanical pulping process
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-39646 (URN)10.1515/npprj-2018-0019 (DOI)2-s2.0-85068744152 (Scopus ID)
Available from: 2019-08-07 Created: 2019-08-07 Last updated: 2019-08-07Bibliographically approved
Mörseburg, K., Hill, J. & Johansson, L. (2016). ATMP refining of Norway spruce - Defibration characteristics and fibre wall properties. Nordic Pulp & Paper Research Journal, 31(3), 386-400
Open this publication in new window or tab >>ATMP refining of Norway spruce - Defibration characteristics and fibre wall properties
2016 (English)In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 31, no 3, p. 386-400Article in journal (Refereed) Published
Abstract [en]

Defibration and fibre development patterns were investigated for the novel ATMP refining process, based on pilot scale trials with Norway spruce chips. ATMP refining with different chemical agents was compared to RTS refining with and without Impressa-finer (RT) and Fiberizer (F) pre-treatment. RT-F pre-treatment significantly improved both initial defibration, axial fibre splitting and fibre flexibility, compared to RTS primary stage refining without pre-treatment. Both types of investigated ATMP process chemistry - hydrogen peroxide combined with magnesium hydroxide under alkaline conditions (P) or acid sodium bisulphite (S) added to the primary refiner dilution water - further improved the fibre separation of RT-F pre-treated wood during primary stage RTS refining. This is largely attributed to enhanced fibre swelling. S-treatment facilitated frequent fibre separation within or close to the S2 wall layer, yielding extremely low shive levels and well-fibrillated, thin-walled fibres early in the process. S-treatment also rendered stiffer fibres, which made them susceptible to breakage, axial splitting and internal delamination. P-application is proposed to affect primarily the interior layers of the fibre walls, facilitating rapid fibre wall swelling towards the lumen, fibre softening and flexibilization.

Keywords
ATMP, Defibration, Energy efficiency, Fibre development, High-consistency refining, Pre-treatment, RTS, TMP
National Category
Paper, Pulp and Fiber Technology
Identifiers
urn:nbn:se:ri:diva-18929 (URN)10.3183/npprj-2016-31-03-p386-400 (DOI)2-s2.0-84982104879 (Scopus ID)
Available from: 2016-10-26 Created: 2016-10-26 Last updated: 2019-06-11Bibliographically approved
Schachtl, M., Erren, S., Scliönhaber, D., Dahlbom, P., Steinsli, J. H. & Johansson, L. (2016). Experiences with "dithionite Based Additives (DBA) in (C)TMP" in lab, pilot and mill scale: Synergies between high brightness, less specific energy consumption and development of pulp properties. In: International Mechanical Pulping Conference 2016 (IMPC 2016): . Paper presented at International Mechanical Pulping Conference 2016 (IMPC 2016), September 26-28, Jacksonville, US (pp. 59-69). TAPPI Press
Open this publication in new window or tab >>Experiences with "dithionite Based Additives (DBA) in (C)TMP" in lab, pilot and mill scale: Synergies between high brightness, less specific energy consumption and development of pulp properties
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2016 (English)In: International Mechanical Pulping Conference 2016 (IMPC 2016), TAPPI Press, 2016, p. 59-69Conference paper, Published paper (Other academic)
Abstract [en]

The purpose of this paper is to report about our experiences with treating softwood mechanical pulp (MP) with DBA directly injected into the gap of high consistency (HC) refiners used as chemical reactors to improve the competitiveness and the ecological footprint of (C)TMP based products. After the description of the main factors and pros and cons of conventional oxidative and reductive bleaching of sofhvood MP the basic principles of the treatment of MP with DBA in the (C)TMP refiner are outlined. By means of exemplary results of trials in lab, pilot and mill scale as well as of productions the main advantages of "DBA in (C)TMP" are illustrated: efficient brightness gain, reduction of anionic trash, high wood yield, reduction of hard chelating agents, saving of refining energy and increase of strength properties. Using the example of Norske Skog Skogn it is demonstrated how the system works in practice in the production of high bright and standard newsprint made from normal and lower quality wood. Finally it is pointed out that to a certain extent DBAs can be tailored to the needs of the respective mill.

Place, publisher, year, edition, pages
TAPPI Press, 2016
National Category
Paper, Pulp and Fiber Technology Nano Technology
Identifiers
urn:nbn:se:ri:diva-27889 (URN)2-s2.0-85006483270 (Scopus ID)9781510830738 (ISBN)
Conference
International Mechanical Pulping Conference 2016 (IMPC 2016), September 26-28, Jacksonville, US
Available from: 2017-01-17 Created: 2017-01-17 Last updated: 2019-06-20Bibliographically approved
Mörseburg, K., Hill, J., Nyseth, T.-E. & Johansson, L. (2014). Understanding energy efficiency of different refining concepts from fibre and fines quality (ed.). In: : . Paper presented at Presented at the International Mechanical Pulping Conference, June 2-5th 2014, Helsinki, Finland.
Open this publication in new window or tab >>Understanding energy efficiency of different refining concepts from fibre and fines quality
2014 (English)Conference paper, Published paper (Refereed)
Abstract [en]

Comparative pilot refining trials with Norway spruce chips were conducted in order to gain a better understanding of the principal mechanisms on fibre level for achieving radical energy reduction in the novel ATMP refining concept. The ATMP pulping configurations proved superior energy efficiency in pulp quality development, compared to TMP, RTS and F-RTS concepts. Development of high tensile strength did not progress at the expense of light scattering, even with process chemicals present. Extensive testing of individual particles in long fibre, middle and fines fractions in combination with analyses of properties of fraction sheets has shown that Impressafiner/Fiberizer pre-treatment opens the wood structure, allowing for early development of desired single fibre properties and generation of fibrillar fines. Peroxide combined with magnesium hydroxide affected the interior of the fibre walls, thereby facilitating improved fibre flexibility, collapsibility and swelling. Bisulphite mainly affected the fibre length distribution, reducing the coarse fraction R14 and promoting the generation of considerable amounts of coarse fines and middle fraction particles.

National Category
Paper, Pulp and Fiber Technology
Identifiers
urn:nbn:se:ri:diva-9673 (URN)2-s2.0-85067736532 (Scopus ID)
Conference
Presented at the International Mechanical Pulping Conference, June 2-5th 2014, Helsinki, Finland
Available from: 2016-09-12 Created: 2016-09-12 Last updated: 2019-08-14Bibliographically approved
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0001-5522-0009

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