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  • 51.
    Hellström, Lisbeth
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Gradin, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Gregersen, Øyvind
    Department for Chemical Engineering, NTNU, Trondheim, Norway.
    Properties of wood chips for thermomechanical pulp (TMP) production as a function of spout angle2011In: Holzforschung, ISSN 0018-3830, E-ISSN 1437-434X, Vol. 65, no 6, p. 805-809Article in journal (Refereed)
    Abstract [en]

    Spruce woodchipswere produced under well-controlled conditions in a laboratory woodchipper at spout angles of 30°, 40°, and 50° at a cutting rate of 20 m s-1 and with a nominalchip length of 25 mm. Thechips were then refined under thermomechanical pulp (TMP) conditions in a pilot refiner plant. The pulpproperties such as freeness, average fiber length, and shives content were determined and evaluated as a function of specific energy consumption. For a first stage refining and for a freeness value of 350 ml, a decrease in specific electrical energy consumption could be achieved by performing thewood chipping at a spout angle of 50° as compared to 30° which is the spout angle commonly used. A patent application regarding this method has been filed and is pending. It is realized that a freeness value is not directly indicative of any quality measure, such as, for example tensile index and light scattering coefficient but the obtained results can be interpreted to be promising. Further studies are needed regarding the impact of the modified chipping process.

  • 52.
    Henshaw Osong, Sinke
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Dahlström, Christina
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Forsberg, Sven
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Andres, Britta
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Norgren, Sven
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Olin, Håkan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Engström, Ann-Christine
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Development of CTMP-based nanofibrillated Cellulose /nanographite composites for paper applications2015Conference paper (Other academic)
  • 53.
    Henshaw Osong, Sinke
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Norgren, Sven
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Pettersson, Gunilla
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    The use of cationic starch and microfibrillated cellulose to improve strength properties of CTMP-based paperboardManuscript (preprint) (Other academic)
  • 54.
    Höglund, Hans
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Pettersson, Gunilla
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Norgren, Sven
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    A paper or paperboard product comprising at least one ply containing high yield pulp and its production method2018Patent (Other (popular science, discussion, etc.))
  • 55.
    Joelsson, Tove
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Pettersson, Gunilla
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Norgren, Sven
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Svedberg, Anna
    MoRe Research Örnsköldsvik AB.
    Höglund, Hans
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    High strength paper from high yield pulps by means of hot-pressing2020In: Article in journal (Refereed)
  • 56.
    Joelsson, Tove
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Pettersson, Gunilla
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Norgren, Sven
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Svedberg, Anna
    MoRe Research Örnsköldsvik AB.
    Höglund, Hans
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Improved paper wet-strength by increasing lignin content and hot-pressing temperature2020In: Article in journal (Refereed)
  • 57.
    Joelsson, Tove
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Pettersson, Gunilla
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Norgren, Sven
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Svedberg, Anna
    MoRe Research Örnsköldsvik AB.
    Höglund, Hans
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Unique steel belt technology for hot-pressing of wood-containing papersManuscript (preprint) (Other academic)
  • 58.
    Karlsson, Anette
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Paulsson, Magnus
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Hedenström, Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Reduced heat-induced darkening and enhanced bleachability of mechanical pulps studied using the UV-visible absorption spectraManuscript (preprint) (Other academic)
  • 59.
    Karlsson, Anette
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering. SCA R and D Centre AB, SE-851 21 Sundsvall, Sweden.
    Paulsson, Magnus
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering. AkzoNobel Pulp and Performance Chemicals, SE-445 80 Bohus, Sweden.
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Hedenström, Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Strategies to reduce heat-induced darkening for enhanced bleachability of mechanical pulps2014In: Appita journal, ISSN 1038-6807, Vol. 67, no 1, p. 50-57Article in journal (Refereed)
    Abstract [en]

    Under mechanical pulping conditions, elevated temperature initiates reactions in the wood constituents resulting in the formation of coloured structures. In an attempt to reduce the formation of colour, a number of additives have been examined to assess their ability to inhibit heat-induced darkening of a Norway spruce (Picea abies) stone groundwood (SGW) pulp. SGW pulp was used as a model pulp with the purpose of imitating a thermomechanical pulp (IMP). The heat-treated SGW pulp, both with and without additives present, was subsequently bleached with 4.5% hydrogen peroxide at high pulp consistency and with varying alkali charges in order to examine the hydrogen peroxide bleachability of such pulps. Heat treatment at 170 °C resulted in a loss of brightness of about 4% ISO after heating for 60 seconds. The reduction in brightness could only partly be regained through high consistency hydrogen peroxide bleaching; the SGW pulp displayed a brightness of 83.7% ISO whereas the heat-treated SGW pulp reached a brightness of 80.4% ISO. Heat treatment with a low addition rate (1 %) of alkaline hydrogen peroxide, sodium bisulfite or sodium sulfite, with a subsequent hydrogen peroxide bleaching stage, resulted in an improved bleached brightness of about 81.6% ISO, i.e. the loss of brightness due to heat was still approximately 2% ISO. Sodium borohydride (1 %) did not suppress the thermal darkening but improved the bleached brightness by approximately 2% ISO compared to the heat-treated SGW pulp and resulted in a brightness of 82.6% ISO. Addition of a chelating agent (DTPA, 0.11 and 0.45%) and the radical scavengers phthalic hydrazide (1 %) and 1 -hexanol (1 %) suppressed the heat-induced darkening somewhat but did not improve the hydrogen peroxide bleachability to any noticeable extent. Addition of citric acid (0.6%) did not suppress the thermal darkening and resulted in impaired bleachability.

  • 60.
    Karlström, A.
    et al.
    Chalmers University of Technology, Göteborg.
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Refining efficiency for future CTIVIP and TMP systems co-optimizing fundamental wood material knowledge with a soft sensor control approach2016In: International Mechanical Pulping Conference 2016, IMPC 2016, TAPPI Press, 2016, p. 304-316Conference paper (Refereed)
    Abstract [en]

    Internal variables in (C)TMP-refining processes (e.g. temperature, consistency, fiber residence time, backward flowing steam and forces acting upon the chips and pulp) are defined as physical states obtained in different parts of the refining zones. In short, they differ from the traditional external variables (e.g. dilution water feed rate, load and gap distance) which are not available as distributed variables from refining zone measurements. The internal variables are the backbone of physical models and such models can be used for on-line implementation of soft sensors and advanced process control. Of special interest are the temperature and consistency profiles together with fiber residence time, which are the internal variables in focus of (in) this study. Moreover, they are directly linked to pulp and handsheet property development. To illustrate the capability to use a modeling strategy, two examples are given; one where it is shown how to reach a 40% reduction in specific energy in a CD82-refiner using a new control strategy without violating the pulp properties studied and one example where the consistency can be controlled individually in two parallel Twin refining zones. Hence, the article comprises both temperature and consistency control to reach optimal process conditions.We believe that increased fundamental understanding of the role of the spatially dependent viscosity in refining in general will be a key factor to find ways to further improve energy efficiency of refining.

  • 61.
    Karlström, A.
    et al.
    Chalmers University of Technology, Göteborg, Sweden .
    Hill, J.
    QualTech AB, Tyringe, Sweden.
    Ferritsius, Olof
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Ferritsius, Rita
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering. Stora Enso Kvarnsveden, Borlänge, Sweden.
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Can we increase the proportion of electrical energy into fibre development in existing HC-refiners?2014In: International Mechanical Pulping Conference, IMPC 2014, Paper Engineers' Association (PI) , 2014Conference paper (Refereed)
    Abstract [en]

    Currently some 5 % of the electrical energy input in high consistency refining can be attributed to fibre development work. The rest is related to thermo- dynatnical steam generation. Can this unfavourable relation between fibre development and heat generation eventually be improved? A pre-requisite to consistent improvement is a stable process, controlled to targets deduced from profound process evaluations. This statement is elaborated based on two case studies and extensive refiner modelling. It is indicated that a well designed process including its basic process control can with proper refiner control reach energy reductions in excess of 20 %. Proper selections of process targets aligned with choice of segments can further increase the energy reduction in existing lines. These drastic energy reductions will demand concurrent observations and process modelling based on spatial measurements in the refining zone rather than slow, inadequate feedback control from pulp property measurements downstream. This will furthermore stress the need for more advanced control schemes if the full potential is to be captured. Additionally this approach will be a key element in the development of novel process approaches with even larger potential of energy reduction.

  • 62.
    Logenius, Louise
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Engberg, Birgitta A.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Fjellström, Helena
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Mechanical Properties of Sulphonated Spruce Wood2013Conference paper (Other academic)
    Abstract [en]

    The chip-refining stage in the production of high yield pulps as TMP and CTMP determines a large part of the optical and mechanical characteristics of the pulp. Softening of the raw material influences where the fiber walls fracture sites will be located.

    In the thermomechanical pulping (TMP) processes, refining is performed at temperatures close to the lignin softening temperature, which normally leads to fractures located in the in the primary wall and outer parts of the secondary wall. When wood material is chemically treated before chip-refining the position of the fracture is altered due to that the softening and swelling properties of the fiber walls are changed. In the chemi-thermomechanical (CTMP) process most of the fractures are, therefore, located in the middle lamella or in the primary wall due to introduction of charged groups in the lignin which facilitates the fiber separation. At alkaline pH phenolic lignin structures are sulphonated, at lower pH non-phenolic structures in the lignin are also sulphonated. In the mechanical pulping processes the wood material is subjected to both low strain rates (e.g. plug screw treatment) and high strain rates (refining). Since wood is a viscoelastic material it behaves differently at different strain rates.

    In this study, sulphonation has been carried out using different sulphite concentrations and pH-levels and we have thereby influenced the sulphonation degree as well as where in the lignin the sulphonation takes place.

    We used a hydraulic testing machine for low strain-rate testing and a Split-Hopkinson pressure bar device for high strain-rate testing to categorize pretreatments according to their material softening effect and the energy needed for fiber separation. This gives us increased fundamental knowledge of how the mechanical properties of wood are affected by the sulphonation in order to develop new/improved pretreatments.

  • 63.
    Logenius, Louise
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Engberg, Birgitta A.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Nelsson, Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering. Holmen Paper.
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Mechanical testing methods for evaluation of the mechanical properties of sulphonated wood2013Conference paper (Other academic)
  • 64.
    Logenius, Louise
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Karlström, A.
    Chalmers Industriteknik, SE-41288 Gothenburg, Sweden.
    Paulsson, Magnus
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Improved hydrogen peroxide bleaching of mechanical pulps using carbon dioxide in combination with sodium and magnesium based alkali sources2011In: 16th International Symposium on Wood, Fiber and Pulping Chemistry - Proceedings, ISWFPC, 2011, Vol. 1, p. 741-745Conference paper (Refereed)
    Abstract [en]

    The pH-profile in the hydrogen peroxide bleaching stage of a Norway spruce thermomechanical pulp was levelled out by using carbon dioxide in combination with sodium or magnesium based alkali sources. Addition of carbon dioxide when magnesium hydroxide was used as the alkali source increased the pulp brightness with up to 1.5 brightness units when the bleaching was performed at 70 °C. When the temperature was increased from 70°C to 90 °C the brightness was increased with about two brightness units, addition of carbon dioxide increased it further. The residual hydrogen peroxide and the chemical oxygen demand (COD) levels were not affected as a consequence of the carbon dioxide addition. In the experiments where sodium hydroxide was used as the alkali source, addition of carbon dioxide lowered the pH that resulted in a decreased COD level, a slightly lower brightness level and, to some extent, an increased residual hydrogen peroxide level.

  • 65.
    Logenius, Louise
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Fjellström, Helena
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    A sustainable analysis of sulphonic acid content in CTMP pulps2014In: International Mechanical Pulping Conference, IMPC 2014, part of PulPaper 2014 Conference, Espoo: Paper Engineers' Association (PI) , 2014Conference paper (Other academic)
    Abstract [en]

    Sulphonic acid analyses were performed on wing refiner chemithermomechanical pulps, low sulphite charge pulps, thermomechanical pulps and on wood samples using a new method referred to as the niacin method. This method gives sulphonic acid content comparable to those estimated with the quinoline method or the Schoniger method. The method gives low interference with carboxylic acids and dissolved substances in the pulp if the pH is kept sufficiently low and the pulp is well washed.

  • 66.
    Muhic, Dino
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Huhtanen, Juha-Pekka
    Sundström, Lars
    Sandberg, Christer
    Ullmar, Mats
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Energy efficiency in double disc chip refining. Influence of intensity by segment design2010In: Proceedings of the 7th InternationalFundamental Mechanical Pulp Research Seminar, Nanjing, China (2010), 2010, p. 103-111Conference paper (Refereed)
  • 67.
    Muhic, Dino
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Huhtanen, Juha-Pekka
    Tampere Univ Technol, Energy & Proc Engn Inst, FIN-33101 Tampere, Finland .
    Sundström, Lars
    Holmen Paper AB Braviken Paper Mill, SE-60188 Norrkoping, Sweden .
    Sandberg, Christer
    Holmen Paper AB Braviken Paper Mill, SE-60188 Norrkoping, Sweden .
    Ullmar, Mats
    Metso Paper, SE-85194 Sundsvall, Sweden .
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Vuorio, Petteri
    Metso Paper Oy, FI-37601 Valkeakoski, Finland .
    Energy efficiency in double disc refining. Influence of intensity by segment design2011In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 26, no 3, p. 224-231Article in journal (Refereed)
    Abstract [en]

    The goal with this work was to study the effect of segment design on electrical energy consumption and pulp quality in double disc TMP production. Mill scale trials were performed with refiner segments from Metso, which were designed based on the fluid dynamics theory. The calculated intensity for the different segments was related to the measured pulp quality. Refining with the high intensity segments (Turbine (TM)) produced pulp with similar tensile index and a significantly higher specific light scattering coefficient at certain specific energy consumption when compared with the reference segments. One drawback with the high intensity segments was the limited operating window due to fibre cutting. The trials showed that segment performance can be modelled, which facilitates the development of new segment designs.

  • 68. Muhic, Dino
    et al.
    Sundström, L
    Nilsson, L
    Sandberg, C
    Ullmar, M
    Backlund, U
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Influence of temperature on energy efficiency in double disc chip refining2009In: Proceedings - 2009 International Mechanical Pulping Conference, IMPC 2009, 2009, p. 344-347Conference paper (Refereed)
    Abstract [en]

    As part of the investment project at Holmen Paper Braviken, the primary stage refining system of counter-rotating RGP68DD refiners (Metso) has been investigated. It is considered to be one of the most energy efficient refiners when comparing to e.g. tensile index. The aim with this work is to optimize the refining conditions for the RGP68DD in regard to refining temperature. Full-scale trials were made where SEC and temperature were successively increased at the same time. The SEC was mainly controlled with motor load and production rate. Feed- and housing- pressure were used to control temperature. The results show that stable specific energy consumption, and refining conditions regarding temperature, resulted in a pulp with increased quality.

     

     

  • 69.
    Muhic, Dino
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Sundström, Lars
    Holmen Paper AB Braviken Paper Mill, SE-60188 Norrkoping, Sweden.
    Sandberg, Christer
    Holmen Paper AB Braviken Paper Mill, SE-60188 Norrkoping, Sweden..
    Ullmar, Mats
    Metso Paper, SE-85194 Sundsvall, Sweden.
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Influence of temperature on energy efficiency in double disc chip refining2010In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 25, no 4, p. 420-427Article in journal (Refereed)
    Abstract [en]

    In 2008 Holmen Paper Braviken invested in a new TMP-line. The primary stage refining system of pressurized counter-rotating double disc chip refiners in this TMP line has been investigated. The aim of this work was to improve the energy efficiency through optimization of the refining temperature.The specific refining energy was varied at different refining temperatures. Inlet and housing pressures were used to control temperature. There was no pressure difference between inlet and housing pressure.An increased inlet- and housing pressure (from 4.6 up to 7.1 bar(g)) and thereby refining temperature resulted in a reduction of the energy consumption to same tensile index by 80-150 kWh/adt. The largest energy reduction was attained at low refining energy levels. An increase in energy efficiency may be explained by a decrease in plate gap, probably caused by softer fibre pad and lower steam volume. At constant specific refining energy and elevated temperature, the tensile index and light scattering coefficients were higher, shives content and average fibre length were lower. These results are probably due to the increased intensity resulting from the plate gap reduction.Increased refining pressure proved to have a positive effect on energy efficiency and pulp quality in a long term trial, i.e. throughout a plate-life.

  • 70. Möller, Klaus
    et al.
    Nikko, Airi
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    The effect of multiple recycling on newsprint quality: a large-scale pilot study, performed 1992 -19962002In: PTS-CTP Symposium on Deinking Technology, 22-24 April 2002 Munich Germany, 2002Conference paper (Other academic)
  • 71.
    Nelsson, E.
    et al.
    Holmen AB, New Business Development.
    Sandberg, C.
    Holmen Paper AB, Paper Product Developmen.
    Svensson-Rundlöf, E.
    Holmen Paper AB, Paper Product Developmen.
    Paulsson, Magnus
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering. Akzo Nobel Pulp and Perfomtance Chemicals AB.
    Granfeldt, Thomas
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering. Valmet AB.
    Engberg, Birgitta
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Mill scale production of TMP with double disk refining-The effects of a mild sulfonation, atmospheric preheating and refining temperatures2016In: International Mechanical Pulping Conference 2016, IMPC 2016, TAPPI Press, 2016, p. 249-259Conference paper (Refereed)
    Abstract [en]

    The aim of this work was to study the effects of a mild dosage of sodium sulfite in chip impregnation at diffen temperatures during atmospheric preheating and during refining for production of TMP for printing papers usi high intensity double disk refining. Two trials were performed in the 800 bdt/day double disc line at I Braviken paper mill (Holmen Paper AB, Sweden) using Norway spruce chips. During the trials, chips w( impregnated in an Impressafiner where chips were preheated at 1.8 bar(g) for a few seconds and th compressed before impregnation. During impregnation, sodium sulfite was added to chips at pH 9 in dosages 0.6 or 1.2%. Reference pulps without addition of sulfite were also produced. In the first trial, the effect different temperatures and retention times (80°C for 6 minutes vs. 96°C for 9 minutes) in the atmosphe preheating bin following impregnation was evaluated both with and without the addition of 1.2% sodium sulf In the second trial, the effect of different refining temperatures (refiner house pressures of 4.6 or 6.4 bar(g), 1 or 167°C) was evaluated with different additions of sodium sulfite (0.0, 0.6 or 1,2%) during impregnation. The results from the two trials showed that the increase in refiner house pressure increased the tensile index pulps both with and without addition of sodium sulfite, when compared at certain SEC. However, the increase preheater bin temperature and retention time did not increase the tensile index of pulps but rather led to a sm reduction in tensile index when combined with an addition of 1.2% sodium sulfite. The two different methc used to increase the temperature in the system led to different effects in the disc gap at certain SEC. The disc j temperature was increased by both methods but disc gap was only reduced at certain SEC when the refini temperature was increased by increasing the refiner housing pressure. The difference in the effect on the disc j may hold the answer to the different effects seen in tensile index.

  • 72.
    Nelsson, Erik
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering. Holmen AB.
    Paulsson, Magnus
    Akzo Nobel Pulp and Performance Chemicals AB.
    Sandberg, Christer
    Holmen Paper AB, Norrköping.
    Svensson-Rundlöf, Eva
    Holmen Paper AB, Norrköping.
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Low dosage sulfite pretreatment at different refining temperatures in mill scale TMP production2017In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 32, no 1, p. 59-69Article in journal (Refereed)
    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.

  • 73.
    Nelsson, Erik
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Sandberg, Christer
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Svensson-Rundlöf, E
    Muhic, D
    Engberg, Birgitta A.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Substantially improved energy efficiency in mechanical pulping by new feeding segment design and low dosage sulfonation in mill scaleArticle in journal (Refereed)
  • 74.
    Nelsson, Erik
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Sandberg, Christer
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Svensson-Rundlöf, Eva
    Holmen Paper AB, S-60188 Norrkoping, Sweden.
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Fernando, Dinesh
    Swedish Univ Agr Sci, Dept Forest Prod Wood Sci, S-75007 Uppsala, Sweden.
    Daniel, Geoffrey
    Swedish Univ Agr Sci, Dept Forest Prod Wood Sci, S-75007 Uppsala, Sweden.
    Low dosage sulfite pretreatment in a modern TMP-line2015In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 30, no 4, p. 591-598Article in journal (Refereed)
    Abstract [en]

    The effects of low dosage sulfite pretreatment combined with modern high consistency double disc refining were evaluated for production of thermomechanical pulp in a mill scale trial using Norway spruce wood at the Braviken paper mill (Holmen Paper AB, Sweden). Spruce wood chips were mechanically pretreated in an Impressafiner before impregnation with different dosages (0-1.2%) of sodium sulfite (Na2SO3) at pH 9. Approximately 23% of the added sulfite was converted to sulfonate groups in pulp, resulting in a sulfonate content of 0-0.28% (as Na2SO3). The low dosage sulfite addition increased tensile index, elongation, density, brightness and decreased shive content, light scattering and light absorption coefficients when compared at equal specific energy consumption (SEC). The increase in tensile index was proportional to dosage of sulfite. Further analyses showed that low dosage sulfite addition did not affect the distribution of the Bauer-McNett fractions nor the fibre length for pulps refined with equal SEC. However, the low dosage sulfite addition increased fibre delamination/internal fibrillation (D/IF). With the addition of 1.2% Na2SO3, it was possible to produce pulp with a tensile index of 47 Nm/g using ~320 kWh/bdt (~15%) lower refining energy, compared with pulps produced without sulfite addition.

  • 75.
    Nelsson, Erik
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Sandberg, Christer
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Svensson-Rundlöf, Eva
    Muhic, Dino
    Valmet AB.
    Rohdén, Lennart
    A. Engberg, Birgitta
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Improved energy efficiency in thermomechanical pulping through co-optimixation of intensity by segment design and wood softening by sulfonation2014In: International mechanical pulping conference IMPC 2014, 2014Conference paper (Other academic)
    Abstract [en]

    A mill scale trial was performed where chips were mechanically pretreated and impregnated with sodium sulfite (<7.2 g/kg). Pretreated chips were refined in two parallel double disc refiners (RGP68DD) using two different conditions: Turbine™ segment at higher production rate (higher intensity) and Low Shive™ segment at normal production rate (lower intensity). By combining the Turbine segments with chip pretreatment using a sodium sulphite charge of 3.6 g/kg it was possible to reduce the specific energy consumption by 15%, while maintaining pulp properties, compared with the lower intensity refining without pretreatment.

  • 76.
    Nordin, Lisa
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    O'Nils, Mattias
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Bäck, Roland
    SCA R&D Centre.
    Ferritsius, Olof
    Pöyry Sweden AB.
    Ferritsius, Rita
    Pöyry Sweden AB.
    Sandberg, Christer
    Holmen Paper Development Centre.
    Sundvall, Öjvind
    Eurocon Analyzer AB.
    Analysis of the quality of optical fibre and fines measurement for prediction of dewatering characteristics for mechanical pulpsManuscript (Other academic)
    Abstract [en]

    The quality of the optical fibre and fines measurement has been investigated. Fibres and fines of different quality were mixed in defined proportions and the mixtures were characterized by means of optical fibre measurements and dewatering behaviour. The results show that the same measured fines amounts show different dewatering behaviour, depending on the quality of the fines used. The difference in fines quality was, however, not reflected in the optical measurement. We conclude that this is caused by too low resolution in the optical measurement, so there is a large need for higher resolution of the measurement equipments in order to make it possible to measure the shape of the fines.

  • 77.
    Nordin, Lisa
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    O'Nils, Mattias
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Bäck, Roland
    SCA R&D Center.
    Ferritsius, Olof
    Pöyry.
    Sandberg, Christer
    Holmen Paper Development Centre.
    Measurement and prediction of dewatering characteristics for mechanical pulps using optical fibre analyzers2009In: Proceedings - 2009 International Mechanical Pulping Conference, IMPC 2009, 2009, p. 309-316Conference paper (Refereed)
    Abstract [en]

    The aim of this work was to obtain an on-line measurement for dewatering behaviour in the wire section based on fibre and fines characteristics. Four laboratory dewatering equipments were compared and the fibre characteristics were measured by means of optical fibre analyzers.

    The results show that rough correlations do appear to exist between the dewatering equipments; however they rank the pulps differently depending on the raw wood material used and whether the refining conditions are mild or harsh. The prediction models based on fibre characteristics showed a high degree of statistical accuracy. The descriptions, however, proved not to be sufficiently good with regards to the dewatering behaviour for them to be used in relation to on-line applications. This might have been because consideration was not given to some important variables which do, in fact, have a significant impact on the drainability. These variables could include physical fibre properties or others that are not measured, or properties that, at present, are unable to be measured at a sufficient resolution.

  • 78.
    Nordin, Lisa
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    O'Nils, Mattias
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Sundvall, Öjvind
    Eurocon Analyzer AB.
    Characterization and classification of dewatering measurement techniques for mechanical pulps2008In: Proceedings of the PRS, Finland, May 2008., 2008Conference paper (Refereed)
  • 79.
    Nordin, Lisa
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    O´Nils, Mattias
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Sundvall, Öjvind
    Towards relevant dewatering measurement techniques: Caracterisation and classification of dewatering measurement techniques for mechanical pulps2008In: FMPRS May 2008, 2008Conference paper (Refereed)
  • 80.
    Nordin, Tommy
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering. MoRe Research Örnsköldsvik AB.
    Svedberg, Anna
    MoRe Research Örnsköldsvik AB.
    Norgren, Sven
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Pettersson, Gunilla
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    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 Technology2018In: IMPC 2018, Trondheim, Norway, 2018Conference 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.

  • 81.
    Osong, Sinke H.
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Norgren, Sven
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    A New Concept to Produce Nano-ligno-cellulose Materials by Means of High Pressure Homogenization2012Conference paper (Refereed)
  • 82.
    Osong, Sinke H.
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Norgren, Sven
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Mechanical Properties of high-yield pulp handsheets, as affected by blends of Nano-ligno-cellulose2013Conference paper (Refereed)
  • 83.
    Osong, Sinke H.
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Norgren, Sven
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    New Products based on Mechanical Pulps: Nano-ligno-cellulose (NLC)2013Conference paper (Refereed)
  • 84.
    Osong, Sinke H.
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Norgren, Sven
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Nano-ligno-cellulose as strength enhancer in handsheets2013Conference paper (Other academic)
    Abstract [en]

    In recent years, there has been tremendous work in the research field of nanocellulose or microfibrillated cellulose but, very few scholars have envisioned the use of the low quality fibre fraction of mechanical pulps for the production of mechanical pulp based nanocellulose, referred to as nano-ligno-cellulose (NLC) in this paper. Today, it has been noticed by many that there has been an economic downturn in the pulp and paper industry and that this adverse situation could be somewhat alleviated by possibly searching for better products or by improving the material quality of existing products (papers and paperboards). This paper presents results related to paper strength properties based on testing of handsheets of pulp fibres blended with nanocellulose. The results indicate that the addition of nano-ligno-cellulose (NLC) to chemi-thermomechanical pulp (CTMP) fibres improved the z-strength property of laboratory sheets with only a slight effect in relation to the sheet density. Also the crill characterisation method was used to evaluate fibre size distribution. The measurement of crill is based on optical response of a suspension at two wavelengths of light; UV and IR. The UV light contains information on both the total fibres and the crill, while IR only contains information on fibres. Results showed that the crill value of NLC of CTMP correlated (linearly) fairly well with the homogenisation time.

  • 85.
    Osong, Sinke H.
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Norgren, Sven
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Nano-ligno-cellulose from mechanical pulp fines2013Conference paper (Refereed)
  • 86.
    Osong, Sinke H.
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Norgren, Sven
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Recent developments in nano-ligno-cellulose production and the crill characterization technique2014In: TAPPI International Conference on Nanotechnology for Renewable Materials 2014, TAPPI Press, 2014, p. 193-205Conference paper (Refereed)
  • 87.
    Osong, Sinke H.
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Norgren, Sven
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Lundberg, Mathias
    PulpEye AB Örnsköldsvik Sweden.
    Reza, Mehedi
    Aalto University, School of Science and Technology, Aalto, Finland.
    Tapani, Vuorinen
    Aalto University, School of Science and Technology, Aalto, Finland.
    Qualitative evaluation of microfibrillated cellulose usingthe crill method and some aspects of microscopy2016In: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 23, no 6, p. 3611-3624Article in journal (Refereed)
    Abstract [en]

    It has been a challenge to develop rapid online characterisation techniques for nanocellulose given the fibrillar structure of the nanoparticles. The crill optical analyser uses optical response signals in the infrared (IR) and ultraviolet (UV) wavelength ranges to evaluate the particle size properties of micro/nanofibrillar cellulosic materials. In this work, the crill analyser was used to measure the projected areas of UV and IR light sources by measuring the light blocked by nanocellulosic particles. This work uses the crill methodology as a new, simplified technique to characterise the particle size distribution of nanocellulosic material based on chemi-thermomechanical pulp (CTMP), thermomechanical pulp (TMP), and sulphite pulp (SP). In the first part, hydrogen peroxide pretreatment of CTMP and TMP in a wing mill refiner followed by high-pressure homogenisation to produce microfibrillated cellulose (MFC) was evaluated using the crill method. In the second part, TEMPO oxidation of CTMP and SP combined with high-shear homogenisation to produce MFC was studied using the crill method. With 4 % hydrogen peroxide pretreatment, the crill values of the unhomogenised samples were 218 and 214 for the TMP and CTMP, respectively, improving to 234 and 229 after 18 homogenisation passes. The results of the TEMPO method indicated that, for the 5 mmol NaClO SP-MFC, the crill value was 108 units at 0 min and 355 units after 90 min of treatment, a 228 % improvement. The CTMP and TMP fibres and the MFC were freeze dried and fibrillar structure of the fibres and microfibrils was visualised using scanning electron and transmission electron microscopy.

  • 88.
    Osong, Sinke H.
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Norgren, Sven
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Pettersson, Gunilla
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Còrdova, Armando
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Afewerki, Samson
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Alimohammadzadeh, Rana
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Processing of nanocellulose and applications relating to CTMP-based paperboard and foams2016In: International Mechanical Pulping Conference 2016, IMPC 2016, TAPPI Press, 2016, p. 87-93Conference paper (Refereed)
    Abstract [en]

    Although remarkable success has been made in the production of nanocellulose through several processing methods, it still remain a challenge to reduce the overall energy consumption, to use green chemistry and sustainable approach in order to make it feasible for industrial production of this novel nanomaterial. Herein, we have developed a new eco-friendly and sustainable approach to produce nanocellulose using organic acid combined with high-shear homogenisation, made hydrophobisation of nanocellulose and cross-linked the modified nanocellulosic material. Also, TEMPO-mediated oxidised nanocellulose was produced in order to compare the processing route with that of mild organic acid hydrolysis. Freeze-dried 3D structure of TEMPO-derived nanocellulose foam materials made fi-om bleached sulphite pulp and CTMP, respectively. Further, there is growing interest in using nanocellulose or microfibrillated cellulose (MFC) as an alternative paper sfrength additive in papermaking, and in using chemi-thermomechanical pulp (CTMP) with high freeness in producing CTMP-based paperboard with high bulk properties. To achieve greater strength improvement results, particularly for packaging paperboards, different proportions of cationic starch (CS) or MFC can be used to significantly improve the z-strength, with only a slight increase in sheet density. Research in this area is exploring CS or MFC as potential strength additives in CTMP-based paperboard, which is interesting from an industrial perspective. The mean grammage of the CTMP handsheets produced was approximately 150 g m~, and it was found that blending CTMP with CS or MFC yielded handsheets with significantly improved z-strength, tensile index, burst index and other strength properties at similar sheet densities.

  • 89.
    Osong, Sinke Henshaw
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Dahlström, Christina
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Forsberg, Sven
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences. Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Andres, Britta
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Norgren, Sven
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Engström, Ann-Christine
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Nanofibrillated cellulose/nanographite composite films2016In: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 23, no 4, p. 2487-2500Article in journal (Refereed)
    Abstract [en]

    Though research into nanofibrillated cellulose (NFC) has recently increased, few studies have considered co-utilising NFC and nanographite(NG) in composite films, and, it has, however been a challenge to use high-yield pulp fibres (mechanical pulps) to produce this nanofibrillar material. It is worth noting that there is a significant difference between chemical pulp fibres and high-yield pulp fibres, as the former is composed mainly of cellulose and has a yield of approximately 50 % while the latter is consist of cellulose, hemicellulose and lignin, and has a yield of approximately 90 %. NFC was produced by combining TEMPO (2,2,6,6-tetramethypiperidine-1-oxyl)-mediated oxidation with the mechanical shearing of chemi-thermomechanical pulp (CTMP) and sulphite pulp (SP); the NG was produced by mechanically exfoliating graphite. The different NaClO dosages in the TEMPO system differently oxidised the fibres, altering their fibrillation efficiency. NFC-NG films were produced by casting in a Petri dish. We examine the effect of NG on the sheet-resistance and mechanical properties of NFC films. Addition of 10 wt% NG to 90 wt% NFC of sample CC2 (5 mmol NaClO CTMP-NFC homogenised for 60 min) improved the sheet resistance, i.e. from that of an insulating pure NFC film to 180 Omega/sq. Further addition of 20 (CC3) and 25 wt% (CC4) of NG to 80 and 75 wt% respectively, lowered the sheet resistance to 17 and 9 Omega/sq, respectively. For the mechanical properties, we found that adding 10 wt% NG to 90 wt% NFC of sample HH2(5 mmol NaClO SP-NFC homogenised for 60 min) improved the tensile index by 28 %, tensile stiffness index by 20 %, and peak load by 28 %. The film's surface morphology was visualised using scanning electron microscopy, revealing the fibrillated structure of NFC and NG. This methodology yields NFC-NG films that are mechanically stable, bendable, and flexible.

  • 90.
    Osong, Sinke Henshaw
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Norgren, Sven
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    An approach to produce nano-ligno-cellulose from mechanical pulp fine materials2013In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 28, no 4, p. 472-479Article in journal (Refereed)
    Abstract [en]

    Mechanical pulping, also called high-yield pulping processes, are pulping systems where a great deal of effort is taken with regards to the fractionation in screens and cleaners as well as to optimize process conditions to refine the rejected fractions. The fraction that is rejected for further treatment can vary from 10 to 50% depending on process strategy and final product which can be from printing paper, writing paper, paperboard middle layer and tissue. In practice, it is common that approximately 10% of the pulp fibres and also a large part of the fines fraction have properties that are unsatisfactory in relation to the final products. Part of the less useful fines fraction could instead be used to produce nano-ligno-cellulose (NLC) of high value either in the main product or used for completely different purposes.

    In order to study the potential of this concept, treatment of thermo-mechanical pulp (TMP) fines fractions were studied by means of homogenization. It seems possible to homogenize fine particles of thermo-mechanical pulp (1% w/v) to NLC. A corresponding fines fraction from bleached kraft pulp (BKP) was tested as a reference at 0.5% w/v concentration. This fines (BKP) fraction was very difficult to homogenize at a higher concentration (1% w/v). An explanation for this could be that the BKP fines have much higher cellulose content and lower charge level compared to the fines fraction of the hemicellulose and lignin-rich TMP. Fibre length-weighteddistribution plays a vital role with respect to both pressure fluctuations and clogging during treatment in the homogenizing equipment.

     

  • 91.
    Osong, Sinke Henshaw
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Norgren, Sven
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Paper strength improvement by inclusion of nano-ligno-cellulose to Chemi-thermomechanical pulp2014In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 29, no 2, p. 309-316Article in journal (Refereed)
    Abstract [en]

    So far, chemical pulp fibres have been utilized as conventional stock materials for nanocellulose production. The main aim of this work is to use stock materials from mechanical or chemi-thermomechanical pulping process to produce lignin containing nanofibres, which are referred to as nano-ligno-cellulose (NLC) in this study. The present study shows the influence on handsheets of chemi-thermomechanical pulp (CTMP) fibres blended with NLC. For comparison reasons, nanocellulose (NC) from bleached kraft pulp (BKP) was produced in a similar approach as NLC. Both the NLC and the NC were blended with their respective pulp fibres and their corresponding handsheets properties were evaluated with respect to sheet density. It was found that the handsheets of pulp fibres blended with NLC/NC improved the mechanical properties of handsheets with only a slight effect in relation to the sheet density. Improvements in strength properties of handsheets such as z-strength, tensile index, tear index, burst index, E-modulus, strain at break, tensile stiffness, air resistance were observed.

  • 92.
    Osong, Sinke Henshaw
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Norgren, Sven
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Processing of wood-based microfibrillated cellulose and nanofibrillated cellulose, and applications relating to papermaking: a review2016In: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 23, no 1, p. 93-123Article, review/survey (Refereed)
    Abstract [en]

    As an emerging cellulosic nanomaterial, microfibrillated cellulose (MFC) and nanofibrillated cellulose (NFC) have shown enormous potential in the forest products industry. The forest products industry and academia are working together to realise the possibilities of commercializing MFC and NFC. However, there are still needs to improve the processing, characterisation and material properties of nanocellulose in order to realise its full potential. The annual number of research publications and patents on nanocellulose with respect to manufacturing, properties and applications is now up in the thousands, so it is of the utmost importance to review articles that endeavour to research on this explosive topic of cellulose nanomaterials. This review examines the past and current situation of wood-based MFC and NFC in relation to its processing and applications relating to papermaking.

  • 93.
    Osong, Sinke Henshaw
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Norgren, Sven
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Lundberg, M.
    PulpEye AB, Box 279, SE-891 26 Örnsköldsvik, Sweden.
    Hansen, P.
    INNVENTIA AB, Drottning Kristinas vag 61, Stockholm, Sweden .
    Development of nano-ligno-cellulose produced from mechanical pulp2014In: International Mechanical Pulping Conference, IMPC 2014, 2014Conference paper (Refereed)
    Abstract [en]

    The objective in this work was to develop a methodology for producing mechanical pulp based nano-ligno-cellulose (NLC) from fines fractions. Also there has been a great deal of enthusiasm to evaluate particle size distribution of NLC. In this work the crill characterisation technique was used. The crill values of TMP and CTMP based nano-ligno-celluloses were measured as a function of the homogenisation time. Results showed that the crill value of both TMP-NLC and CTMP-NLC correlated with the homogenisation time. Another objective was to utilise NLC as strength additives in paper and board grades. Laboratory sheets of CTMP and bleached kraft pulp (BKP), with the addition of their respective NLC, were made in a Rapid Kothen sheet former. It was found that handsheets of pulp fibres blended with NLC improved the z- strength and other important mechanical properties for similar sheet densities.

  • 94.
    Osong, Sinke Henshaw
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Norgren, Sven
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Lundberg, Mathias
    PulpEye AB, Box 279, SE-891 26 Örnsköldsvik, Sweden.
    Hansen, Peter
    INNVENTIA AB, Drottning Kristinas väg 61, Stockholm, Sweden.
    Crill: A novel technique to characterize nano-ligno-cellulose2014In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 29, no 2, p. 190-194Article in journal (Refereed)
    Abstract [en]

    The CrillEye is a technique for qualitatively assessing loose slender and fibrillar particles created during pulping. It has also been demonstrated that the crill measurement technique can easily be used to measure the degree of fibrillation of mechanical pulp based nano-ligno-cellulose (NLC). The measurement technique is based on an optical response of a suspension at two wavelengths of light; UV and IR. The UV light contains information on both fibres and crill, while IR only contains information on fibres. The resolution on the CrillEye module is based on optical response of the pulp and on an analogue signal analysis making it concentration independent. Characterization of particle-size distribution of nano-ligno-cellulose is both important and challenging. The objective of the work presented in this paper was to study the crill values of TMP and CTMP based nano-ligno-celluloses as a function of homogenization time. Results showed that the crill value of both TMP-NLC and CTMP-NLC correlated fairly well with the homogenization time.

  • 95.
    Persson, Erik
    et al.
    Holmen Paper Development Center.
    Engstrand, Per
    Holmen Paper Development Center.
    Karlsson, Lennart
    Holmen Paper AB.
    Fredrik, Nilsson
    Holmen Paper AB.
    Wahlgren, Mikael
    Holmen Paper AB.
    Utilization of the natural variation in wood properties–a comparison between pilot plant and mill scale trials2003In: Proceedings of International Mechanical Pulping Conference, Quebec City, 2003, p. 83-90Conference paper (Refereed)
    Abstract [en]

    Four different pulpwood classes of Norway spruce (Picea abies (L.) Karst). were tested in mill scale production of TMP at Hallsta Papermill. The objectives of the trial were to evaluate both rather extreme and more traditional roundwood classes in a full-scale TMP-plant with respect to pulp properties and energy requirements. The experiment was partly based on the results from the proceeding pilot plant trial within the EuroFiber project. The results generally confirmed the findings in the pilot plant trial. Young wood with a high proportion of juvenile wood gave a pulp with attractive optical properties, but somewhat lower tear index and higher energy consumption. The other extreme, sawmill chips from old trees of heavy dimensions, required lower energy input and gave higher tear index, but inferior optical properties. The two more traditional classes gave pulps with properties between the two extremes.

  • 96.
    Pettersson, Gunilla
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Höglund, Hans
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Norgren, Sven
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Peng, F.
    Stora Enso, Karlstad.
    Granfeldt, T.
    Valmet, Sundsbruk.
    Bergström, J.
    SCA Östrand, Timrå.
    Joelsson, T.
    MoRe Research, Domsjö.
    Upgrading the strength properties of sheets from hardwood high yield pulps2018In: Pan Pacific Fibre Value Chain Conference 2018, Proceedings, Appita Inc. , 2018, p. 142-147Conference paper (Refereed)
  • 97.
    Pettersson, Gunilla
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Norgren, Sven
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Höglund, Hans
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Low energy CTMP in strong and bulky paperboard plies2016In: Paper Conference and Trade Show, PaperCon 2016, TAPPI Press, 2016, Vol. 1, p. 556-564Conference paper (Refereed)
  • 98.
    Rahman, Hafizur
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    An, Siwen
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Norlin, Börje
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Fröjdh, Christer
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Persson, Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Maximized wood chip impregnation efficiency validated by new miniaturized X-ray fluorescence techniques2019Conference paper (Refereed)
    Abstract [en]

    Manufacturing of chemi-thermomechanical pulp (CTMP) is increasing due to increased demand for packaging materials such as cardboard as well as tissue and other hygiene products. Today high yield pulp (HYP) is produced from different wood species. It is well-known that chip-refining is normally responsible for more than 60% of the electric energy consumption in most high yield pulping process. There are opportunities to improve energy efficiency and quality stability in defibration processes by means of optimizing impregnation. Impregnation is a key unit operation in CTMP production as well as in all chemical pulping and biorefinery systems. The efficiency of the impregnation is known to be crucial (Ferritsius et al. 1985; Gorski et al. 2010). Early research showed difficulties to achieve even distribution of sulphite and sodium ions in wood chips resulting in inhomogeneous fibre properties (Bengtsson et al. 1988). Increased and homogenous sulphonation leads to reduced shive content, which is a key factor in all end product applications. To address this issue developing a new type miniaturized X-ray based technique (XRF) to measure local concentration of sulphur and sodium across wood chips and in individual fibres could become a key tool.

     

    The presence of elements as sulphur and sodium can be detected by X-ray fluorescence (XRF) or spectral absorption. At the XRF, images the surface of the sample using specific energies from K-shell or L-shell fluorescence. This method is investigated at the X-ray laboratory in Mid Sweden University research centre STC (Sensitive Things that Communicate) (Norlin et al. 2018). At the spectral absorption, images specific K-shell absorption energies in transmission X-ray images of the sample, a method widely used in medical diagnosis. This transmission method might also be further investigated for this application in the future (Frojdh et al. 2013; Reza et al. 2013). Both methods can be validated by using monoenergetic radiation from synchrotron facilities.

     

    An XRF imaging system uses a collimated X-ray source and a spectroscopic detector. The sample is scanned to make an image of the content of the substances of interest. A specific challenge in this case is that the low energy fluorescence photons from sulphur (S) and sodium (Na) are easily absorbed in air, which makes imaging in a different atmosphere necessary.

     

    The measurement setup has been simulated using MCNP (C. J. Werner, 2017) to validate the system setup and to select the correct, geometry, shielding, filtering and atmosphere for the measurement. The solution was to use a titanium box flooded with helium to minimise the absorption of fluorescence photons and to shield from scattered photons that might disturb the measurement, fig 1. A filter has been added to the X-ray source to make it nearly monoenergetic and to avoid emission of photons with energies close to the expected fluorescence. The system has been used to estimate sodium and sulphur content in low grammage handsheet (CTMP) or single wood chip samples. It is possible to build a laboratory instrument similar to the prototype setup to obtain the distribution of sodium and sulphur in XRF imaging.

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

    Figure 1: Photograph of XRF measurement setup with of moveable Helium atmosphere Ti box

    However, the technique we are developing can become useful in mills to improve and control process efficiency, product properties and to find solutions to process problems in future. In addition, a more even distribution of the sulphonation can reduce specific energy demand in chip refining at certain shive content.

     

    References

     

    1.      Bengtsson, G., Simonson, R., Heitner, C., Beatson, R., and Ferguson, C. (1988): Chemimechanical pulping of birch wood chips, Part 2: Studies on impregnation of wood blocks using scanning electron microscopy and energy dispersive x-ray analysis, Nord. Pulp Paper Res. J. 3 (3), 132-138.

    2.      C. J. Werner, (2017): MCNP User's manual, Code Version 6.2, Los Alamos National Laboratory report, LA-UR-17-29981.

    3.      Ferritsius, O., and Moldenius, S. (1985): The effect of impregnation method on CTMP properties. In International Mechanical Pulping Conference Proceedings, SPCI, Stockholm (p. 91).

    4.      Frojdh, C., Norlin, B. and Frojdh, E. (2013): Spectral X-ray imaging with single photon processing detectors, Journal of Instrumentaion, Volume 8, Article number C02010.  

    5.      Gorski, D., Hill, J., Engstrand, P., and Johansson, L. (2010): Reduction of energy consumption in TMP refining through mechanical pre-treatment of wood chips, Nord. Pulp Paper Res. J, 25(2), 156-161.

    6.      Norlin, B., Reza, S., Fröjdh, C. and Nordin, T. (2018): Precision scan-imaging for paperboard quality inspection utilizing X-ray fluorescence, Journal of Instrumentation, Volume: 13, Article number C01021.

    7.      Reza, S., Norlin, B. and Thim, J. (2013): Non-destructive method to resolve the core and the coating on paperboard by spectroscopic x-ray imaging, Nord. Pulp Paper Res. J. 28 (3), 439-442.

     

  • 99.
    Rahman, Hafizur
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Modification of Softwood Kraft Pulp for Improved Tissue Paper2019In: TAPPI PaperCon Conference, Indianapolis, USA, May 5-8, 2019, 2019Conference paper (Refereed)
  • 100.
    Rahman, Hafizur
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering. SCA R & D Centre, Sundsvall.
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Sandström, Peter
    SCA R & D Centre, Sundsvall.
    Sjöstrand, B.
    Karlstad University, Karlstad.
    Dewatering properties of low grammage handsheets softwood kraft pulps modified to minimize the need for refining2018In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 33, no 3, p. 397-403Article in journal (Refereed)
    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.

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