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Höglund, H., Pettersson, G., Norgren, S. & Engstrand, P. (2018). A paper or paperboard product comprising at least one ply containing high yield pulp and its production method. se 540115 C2.
Open this publication in new window or tab >>A paper or paperboard product comprising at least one ply containing high yield pulp and its production method
2018 (English)Patent (Other (popular science, discussion, etc.))
National Category
Paper, Pulp and Fiber Technology
Identifiers
urn:nbn:se:miun:diva-33506 (URN)
Patent
SE 540115 C2
Note

International application WO 2018054957 A1.

Available from: 2018-04-17 Created: 2018-04-17 Last updated: 2018-04-17Bibliographically approved
Samuelsson, T., Pettersson, G., Norgren, S., Svedberg, A., Höglund, H. & Engstrand, P. (2018). Development of strong and water resistant packaging materials from high yield pulps – fundamental aspects. In: IMPC 2018: . Paper presented at International Mechanical Pulping Conference (IMPC) 2018, May 27-30, 2018, Trondheim, Norway. Trondheim, Norway
Open this publication in new window or tab >>Development of strong and water resistant packaging materials from high yield pulps – fundamental aspects
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2018 (English)In: IMPC 2018, Trondheim, Norway, 2018Conference paper, Published paper (Refereed)
Abstract [en]

This work is focused on fundamental aspects of the densification of paper sheets during hot-pressing under conditions where the lignin in the fibre walls is softened. In this study light microscope and scanning electron microscope (SEM) techniques were used to reveal the mechanisms in the fibre network structure within the paper sheets that arises due to densification and the impact of lignin. UV and staining methods and spectrometric observations of the ultrastructure of cross section of paper sheets and fibre surfaces will highlight the changes that occur in the fibre structures. This study improves the understanding of how fibres collapse and how internal fibre-fibre bonds in lignin-rich mechanical pulp affect the physical properties of the final paper sheet. To demonstrate this, paper sheets from five different pulps containing different concentration of natural lignin were produced. Handsheets of 150 g/m2 were prepared in a Rapid Köthen (RK) laboratory sheet former, where the sheets were press-dried at 100 kPa and ca 90oC to a dry content of 45-50% d.c. After 24 hours in room temperature the hand sheets were hot-pressed in a temperature interval from 20 – 200oC at a constant pressure in a cylinder-press at a speed of 1 m/min. The results show that remarkable improvements on paper sheets, based lignin-rich pulps, can be achieved in terms of increased tensile index (up to 85 kNm/kg), compression strength, SCT, (up to 38 kNm/kg) and wet strength (up to 10 kNm/kg), which depends on the densification of the fibre structure at high temperature and pressure in the load nip. It is concluded that this to a major extent is related to that the lignin rich fibres are compressed at high enough temperature to both softened and develop tacky surfaces so that the fibres are locked into their positions within the highly densified sheets. The SEM evaluation shows how the surface structure get dense at pressing at 200oC for the CTMP based paper sheets. The light microscopy studies of the sheet cross sections reveal how the fibres collapse in the case of CTMP based sheets while fibres from bleached kraft pulp based sheets are quite well collapsed already at room temperature.

Place, publisher, year, edition, pages
Trondheim, Norway: , 2018
Keywords
ctmp, densification, hand sheets, hyp, lignin, mechanical pulp, nssc, strength properties, tmp, wet strength
National Category
Paper, Pulp and Fiber Technology
Identifiers
urn:nbn:se:miun:diva-34675 (URN)
Conference
International Mechanical Pulping Conference (IMPC) 2018, May 27-30, 2018, Trondheim, Norway
Available from: 2018-10-09 Created: 2018-10-09 Last updated: 2018-10-09Bibliographically approved
Rahman, H., Engstrand, P., Sandström, P. & Sjöstrand, B. (2018). Dewatering properties of low grammage handsheets softwood kraft pulps modified to minimize the need for refining. Nordic Pulp & Paper Research Journal, 33(3), 397-403
Open this publication in new window or tab >>Dewatering properties of low grammage handsheets softwood kraft pulps modified to minimize the need for refining
2018 (English)In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 33, no 3, p. 397-403Article in journal (Refereed) Published
Abstract [en]

Previous paper (Rahman et al. 2017) showed that the yield of softwood kraft pulp increased by the addition of either polysulfide or sodium borohydride because of higher hemicellulose retention. An increase in hemicellulose content can make dewatering more difficult as WRV of the pulp increases, but instead, an overall increase in pulp yield could improve dewatering as a sheet of a certain weight will contain fewer fibres, giving a more open sheet structure. It was therefore of interest to measure the dewatering properties of low grammage handsheets (20 g/m2) under conditions mimicking the tissue paper machine dewatering processes, and sheet strength properties, WRV, °SR and fibre dimensions were also studied. The results showed that the positive influence of overall yield increase dominated over the negative influence of an increase in hemicellulose content on the dewatering properties, particularly at lower refining energy levels. Moreover, higher yield and higher hemicellulose content pulps had a higher tensile index at the same dryness. A given tensile index was achieved with less refining energy. The results indicate that increased yield and hemicellulose content by modification of the kraft pulping process will result in a pulp with a potential to improve tissue paper quality.

Keywords
dwell time, hemicellulose, refining, solid content, suction box dewatering, tensile index, thermoporosimetry, water retention value
National Category
Chemical Engineering
Identifiers
urn:nbn:se:miun:diva-32836 (URN)10.1515/npprj-2018-3037 (DOI)2-s2.0-85052642839 (Scopus ID)
Available from: 2018-02-12 Created: 2018-02-12 Last updated: 2018-10-03Bibliographically approved
Sandberg, C., Nelsson, E., Engberg, B. A., Berg, J.-E. & Engstrand, P. (2018). Effects of chip pretreatment and feeding segments on specific energy and pulp quality in TMP production. Nordic Pulp & Paper Research Journal, 33(3), 448-459
Open this publication in new window or tab >>Effects of chip pretreatment and feeding segments on specific energy and pulp quality in TMP production
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2018 (English)In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 33, no 3, p. 448-459Article in journal (Refereed) Published
Abstract [en]

Increased wood softening and refining intensity have earlier been utilized to improve refining efficiency in mechanical pulping. We have evaluated a combination of increased softening by low dose sulphite chip pretreatment and increased intensity by feeding segment design in a TMP line for production of high quality printing papers. Norway spruce wood chips were preheated, compressed in an Impressafiner and impregnated with water or sodium sulphite solutions (Na2SO3 charges 3.6 and 7.2 kg/t). Chips were refined in two parallel 68" double disc refiners using two different refining conditions: standard bidirectional segments at normal production rate (9 t/h) and feeding segments at increased production rate (11.1-12.1 t/h). The feeding segments enabled a 30 % increase in production rate. Refining with feeding segments at 12.1 t/h production rate combined with chip pretreatment with 3.6 kg/t sodium sulphite reduced the specific energy 360 kWh/t (19 %) compared to refining with standard segments and no pretreatment. Pulp properties were similar for the two configurations. The combination of feeding segments and chip pretreatment with water reduced the specific energy 180 kWh/t (9 %). Implementation of most of the technology presented has reduced the electrical energy use for the mill by approximately 80 GWh/year.

Keywords
chip pretreatment, double disc refiner, energy efficiency, mechanical pulping, refining intensity, sodium sulphite
National Category
Chemical Engineering
Identifiers
urn:nbn:se:miun:diva-34604 (URN)10.1515/npprj-2018-3052 (DOI)2-s2.0-85053157973 (Scopus ID)
Available from: 2018-10-03 Created: 2018-10-03 Last updated: 2018-10-03Bibliographically approved
Nordin, T., Svedberg, A., Norgren, S., Pettersson, G. & Engstrand, P. (2018). Industrially Relevant In-situ Production Of High Yield Pulp Based Nanocellulose Materials Optimized To Improve Strength In Packaging And Printing Papers: A Comparison Between CMC And MFC As The Anionic Component In Layer-by-Layer Technology. In: IMPC 2018: . Paper presented at International Mechanical Pulping Conference (IMPC) 2018, May 27-30, 2018, Trondheim, Norway. Trondheim, Norway
Open this publication in new window or tab >>Industrially Relevant In-situ Production Of High Yield Pulp Based Nanocellulose Materials Optimized To Improve Strength In Packaging And Printing Papers: A Comparison Between CMC And MFC As The Anionic Component In Layer-by-Layer Technology
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2018 (English)In: IMPC 2018, Trondheim, Norway, 2018Conference paper, Published paper (Refereed)
Abstract [en]

A key issue in papermaking is to understand how to improve strength without losing other important quality measures, like paper bulk. This must of course also be done in a cost efficient way. The trials described in this paper show some different aspects related to the replacement of the expensive anionic component CMC (carboxymethylcellulose) often used in Layer-by-Layer technology together with cationic starch in order to improve strength properties as z-strength and tensile strength of typical chemi-thermomechanical pulp (CTMP) often used as dominating component in industrial scale paper board production. The replacement for CMC investigated here is a MFC (micro-fibrillated cellulose) as the anionic component and paper sheets has been produced on an experimental paper machine at MoRe Research AB. This MFC is a commercially available product and it has not been treated in ways of increasing charge density. The trials were performed at a small pilot scale experimental paper machine (XPM) at MoRe Research in Örnsköldsvik, Sweden. This XPM is equipped with a unique setup to perform Layer-by-Layer-tests under very well controlled conditions. The general conclusion is that it could, with further developments, be feasible to replace CMC with MFC to improve bonding in typical CTMP based paper sheets.

Place, publisher, year, edition, pages
Trondheim, Norway: , 2018
Keywords
cmc, ctmp, layer-by-layer, mechanical pulp, mfc, strength additive
National Category
Paper, Pulp and Fiber Technology
Identifiers
urn:nbn:se:miun:diva-34677 (URN)
Conference
International Mechanical Pulping Conference (IMPC) 2018, May 27-30, 2018, Trondheim, Norway
Available from: 2018-10-09 Created: 2018-10-09 Last updated: 2018-10-09Bibliographically approved
Sandberg, C., Berg, J.-E. & Engstrand, P. (2018). LC refining combined with screen fractionation – Reduction of system complexity for mechanical pulping. In: IMPC 2018: . Paper presented at International Mechanical Pulping Conference (IMPC) 2018, May 27-30, 2018, Trondheim, Norway. Trondheim, Norway
Open this publication in new window or tab >>LC refining combined with screen fractionation – Reduction of system complexity for mechanical pulping
2018 (English)In: IMPC 2018, Trondheim, Norway, 2018Conference paper, Published paper (Refereed)
Abstract [en]

Process intensification - a process development method used in the chemical process industry has been appliedto mechanical pulping process design. Process intensification is characterized by significant reduction of energyconsumption and process complexity.A process with single stage high consistency (HC) refining followed by low consistency (LC) refining andscreening was evaluated in mill trials at the Holmen Paper Braviken mill, Sweden. After LC refining, pulp wasscreened and the reject was fed back to LC refining. The process is called HC-LC-S. Two different HC primaryrefiner types were evaluated – single disc (SD) and double disc (DD).High intensity DD chip refining was more suitable than single disc refining for the process due to higher lightscattering and lower shives content of the final pulp. It was also easier to reach high enough tensile index beforeLC refining with the DD refining. The DD-LC-S process required 1940 kWh/adt total specific energy for newsgrade TMP, which was 300 kWh/adt lower than the reference TMP line; DD chip refining and HC rejectrefining. The auxiliary specific energy was reduced with 100 kWh/adt.Six unit operations and three chests with agitators and pumps were omitted compared to a conventional TMPline.

Place, publisher, year, edition, pages
Trondheim, Norway: , 2018
National Category
Paper, Pulp and Fiber Technology
Identifiers
urn:nbn:se:miun:diva-34674 (URN)
Conference
International Mechanical Pulping Conference (IMPC) 2018, May 27-30, 2018, Trondheim, Norway
Available from: 2018-10-09 Created: 2018-10-09 Last updated: 2018-10-09Bibliographically approved
Ferritsius, O., Ferritsius, R., Rundlöf, M., Engberg, B. A. & Engstrand, P. (2018). The Independent State of Fibres in Relation to the Mechanical Pulping World. In: IMPC 2018: . Paper presented at International Mechanical Pulping Conference (IMPC) 2018, May 27-30, 2018, Trondheim, Norway. Trondheim, Norway
Open this publication in new window or tab >>The Independent State of Fibres in Relation to the Mechanical Pulping World
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2018 (English)In: IMPC 2018, Trondheim, Norway, 2018Conference paper, Published paper (Refereed)
Abstract [en]

Paper and wood are highly inhomogeneous materials. When describing the mechanical pulp itself, we allcommonly ignore that it is an inhomogeneous material. We have realized that just a very small fraction of stifffibres are enough to impair the printability of the product. In this paper we share some of our reflections andattempts how to describe the inhomogeneous nature of mechanical pulps. A method denoted BIN is underdevelopment based on independent common factors and paying attention to the inhomogeneity of the material.The method may give the possibility to describe the nature of TMP/CTMP/SGW in a more relevant way comparedto todays practice. Hence the paper and board makers may be able to deliver more uniform products at “goodenough” level at lower costs. We have realized that because a method or opinion is well spread (sometimes usedby almost everybody) it does not necessarily mean that it is relevant. A couple of myths have been reflected uponand in our opinion they remain just myths. By putting more attention to reality and describing mechanical pulp asan inhomogeneous material we hope to be able to rid ourselves and the mechanical pulping community of someother myths circulating (some still to be discovered).

Place, publisher, year, edition, pages
Trondheim, Norway: , 2018
National Category
Paper, Pulp and Fiber Technology
Identifiers
urn:nbn:se:miun:diva-34680 (URN)
Conference
International Mechanical Pulping Conference (IMPC) 2018, May 27-30, 2018, Trondheim, Norway
Available from: 2018-10-09 Created: 2018-10-09 Last updated: 2018-10-09Bibliographically approved
Sandberg, C., Berg, J.-E. & Engstrand, P. (2017). Low consistency refining of mechanical pulp - system design. TAPPI Journal, 16(7), 419-429
Open this publication in new window or tab >>Low consistency refining of mechanical pulp - system design
2017 (English)In: TAPPI Journal, ISSN 0734-1415, Vol. 16, no 7, p. 419-429Article in journal (Refereed) Published
Abstract [en]

Many mechanical pulping mills use low consistency (LC) refining for energy efficient fiber development. In this study, energy efficiency and pulp quality were evaluated for six processes, of which four included LC refining. We studied two different types of chip refiners - single disc (SD) and double disc (DD) - with LC refining in the main and reject lines. All process combinations have been used in the Holmen Paper Braviken mill, Sweden, to make thermomechanical pulp for printing papers. LC refining was more energy efficient than high consistency (HC) refining at certain tensile index increases in all evaluated combinations. LC refining in the main line had somewhat higher energy efficiency than did LC refining in the reject line. The type of chip refiner (DD or SD) did not affect the efficiency or pulp property development in LC refining. The process with a combination of DD chip refining and LC refining had the highest energy efficiency (tensile index at certain specific energy consumption). All processes with LC refining produced pulp with somewhat lower light scattering and fiber length than did the corresponding system with only HC refining. Thus, for printing papers, the best combination was LC refining with DD chip refining. LC refiners seem to have a narrow range in specific energy for maximum energy efficiency and a good balance between tensile index increase and fiber length reduction. Much higher specific energy was applied on reject pulp. However, the reject share was only around 30%. The LC refining specific energy, based on main line production, was around 80 kWh/air-dried metric ton (a.d. metric ton), whereas up to 180 kWh/a.d. metric ton was applied in main line.

National Category
Chemical Engineering
Identifiers
urn:nbn:se:miun:diva-31894 (URN)000411860500005 ()2-s2.0-85026809547 (Scopus ID)
Available from: 2017-10-18 Created: 2017-10-18 Last updated: 2017-11-29Bibliographically approved
Nelsson, E., Paulsson, M., Sandberg, C., Svensson-Rundlöf, E. & Engstrand, P. (2017). Low dosage sulfite pretreatment at different refining temperatures in mill scale TMP production. Nordic Pulp & Paper Research Journal, 32(1), 59-69
Open this publication in new window or tab >>Low dosage sulfite pretreatment at different refining temperatures in mill scale TMP production
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2017 (English)In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 32, no 1, p. 59-69Article in journal (Refereed) Published
Abstract [en]

The effects of low dosage sodium sulfite ( Na2SO3) pretreatment (0, 0.6 and 1.2% on bone dry wood, pH 9) at two different refining temperatures (4.6 and 6.4 bar(g) refiner housing pressure) were evaluated for production of thermomechanical pulp with a double disc refiner in mill scale using Norway spruce wood at Braviken paper mill (Holmen Paper AB, Sweden). The sulfonate content of the pulps was not affected by the different refining temperatures and was 0.29% (as Na2SO3 equivalents) for the highest sulfite addition.

Tensile index at constant SEC was increased by 3.2 Nm/g when the refining temperature was increased, and by 8.6 Nm/g when 1.2% sodium sulfite was added. The effects were additive and led to an increase in tensile index of similar to 12 Nm/g at constant SEC when combined and would enable a reduction in SEC of 380 kWh/bdt (similar to 20%) to similar tensile index. The degree of delamination and internal fibrillation of the fibers was increased by both increased refining temperature and sulfite addition.

Pulp brightness was slightly reduced (<= 0.4% ISO) by increased refining temperature and increased (2-3% ISO), when sodium sulfite was added. Spectra of reflectance factors (360-740 nm) were used to study the optical properties of produced pulps.

Keywords
Double disc refining, Energy reduction, Mill scale, Norway spruce, Pulp properties, Refining temperature, Sulfite pretreatment, TMP
National Category
Chemical Engineering
Identifiers
urn:nbn:se:miun:diva-27332 (URN)10.3183/NPPRJ-2017-32-01-p059-069 (DOI)000398384400008 ()2-s2.0-85016434323 (Scopus ID)
Available from: 2016-03-24 Created: 2016-03-24 Last updated: 2017-12-18Bibliographically approved
Sandberg, C., Berg, J.-E. & Engstrand, P. (2017). Mill evaluation of an intensified mechanical pulping process. Nordic Pulp & Paper Research Journal, 32(2), 204-210
Open this publication in new window or tab >>Mill evaluation of an intensified mechanical pulping process
2017 (English)In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 32, no 2, p. 204-210Article in journal (Refereed) Published
Abstract [en]

Mill-scale demonstration of a process concept inspired by Process Intensification (PI) principles was performed in Holmen Paper Braviken mill, Norrkoping, Sweden. The intensified process consists of wood softening by means of chip pretreatment with sodium sulphite, high intensity refining followed by low consistency refining. This process yields very low shives content and thus the unit operations screening and reject refining can be eliminated and the pulp is fed directly to the paper machine. Thorough evaluation of key paper-and print quality data showed that it is possible to produce pulp for newsprint at 1500 kWh/adt total specific energy (including auxiliary drives such as pumps, screw feeders, etc.). The total specific energy consumption was 900 kWh/adt lower compared to the normal process used for newsprint in Braviken, and 500 kWh/adt lower compared to today's best available technology. The auxiliary equipment energy demand was 120 kWh/adt, which was less than half of that of the reference TMP line. The PIinspired process reduces the number of machines drastically compared to a conventional TMP line, as well as the number of pumps, chests and other auxiliary equipment.

Keywords
Chip pre-treatment, Double disc refining, Energy efficiency, High intensity, Low-consistency refining, Mechanical pulping, Process control, Process intensification, TMP
National Category
Chemical Engineering
Identifiers
urn:nbn:se:miun:diva-31366 (URN)10.3183/NPPRJ-2017-32-02-p204-210 (DOI)000405197000006 ()2-s2.0-85052714078 (Scopus ID)
Available from: 2017-08-10 Created: 2017-08-10 Last updated: 2018-10-03Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0003-1881-6473

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