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- Engstrand, Per O., 1955-, et al.
(författare)
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Mekmassainitiativet för energieffektivitet, e2mp-i
- 2015
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Projektet har drivits som ett program för finansiering av forskning som ska utveckla ochdemonstrera tekniker som reducerar elenergiförbrukningen med 50% vid tillverkning avTMP och CTMP med bibehållna slutproduktegenskaper hos tryckpapper och kartong.Programmet är en del av skogsindustrins initiativ att under en tioårsperiod tillsammansmed svenska och norska finansiärer investera minst 200 Mkr för att nå detta radikalaeffektiviseringsmål. Ett uttalat mål för industriinitiativet är också att befästaforskningsnoderna vid FSCN i Sundsvall och PFI i Trondheim.Parallellt med Energimyndighetens finansiering, 30 Mkr, har Norges Forskningsråd satsat25 MNOK (2010‐14) i industriinitiativet, KK‐stiftelsen 36 MSEK (2011‐17) ochMittuniversitetet har finansierat12 MSEK. Industrins totala satsning kommer att överstiga100 MSEK redan vid utgången av 2017.Resultat från benchmarkingstudien BAT2012 av industrins modernaste TMP‐ och CTMPlinjersamt från demonstrationsskaleprojekt visas i rapporten. Projekten baseras delvis pågrundläggande forskningsprojekt genomförda inom FSCN´s KK‐stiftelse‐finansieradeforskningsprofil och projektet ”Filling the Gap” 31676‐, ISSN 1650‐5387 2014:57. Resultaten visar följande reduktionsnivåer; 28% TMP för news (Braviken), 14% TMP för SC(Kvarnsveden) och 21% CTMP för kartong (Skoghall).Utöver demoprojekten finns ytterligare tydliga potentialer beskrivna i övriga delprojekt:Processintensifiering och processmodifiering > 15%Processtabilitet via avancerad processanalys och reglering > 15%Kombinera effektivaste processavsnitt från benchmarking ca 25%Detta gör det troligt att det kommer att gå att i fullskaliga demonstrationsförsök validera50% elenergireduktion inom de tre produktområdena, förutsatt att fortsattforskningsfinansiering finns tillgänglig. Tre av de idéer till avknoppningsprojekt somframkommit under projektets gång har redan erhållit beslut om finansiering frånEnergimyndigheten 2015. Ytterligare projektförslag baserade på den här redovisadeforskningen kommer att ingå i ansökningar under 2016. Utöver energireduktion i själva TMP‐ och CTMP‐processerna har forskare vid FSCN lagt forskningsgrunden för hur manska kunna tillverka mycket starka förpackningsmaterial från dessa massatyper på ettenergieffektivt sätt. Även inom detta område kommer en ansökning omuppskalningsprojekt att skickas in.
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| 3. |
- Ferritsius, Olof, et al.
(författare)
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Heterogeneity
- 2019
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Ingår i: Heterogeneity.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Heterogeneity may be a most proper word to describe paper and board. Wood, the raw material to produce mechanical pulps, is almost as heterogeneous a material as the products. Looking in a microscope at a mechanical pulp it is obvious that it consists of a huge amount of small particles, which vary very much in several aspects: length, curl, width, wall thickness, fibrillation etc. In spite of that, we (scientists, mill employees, suppliers, consultants, researchers) commonly describe a pulp in terms of collective properties such as averages of fibre dimensions, hand sheet properties, dewatering ability etc. In other words: we describe mechanical pulp as a continuum. This may be more common than we believe. A review of the variables used in the more than 5,000 graphs in the preprints of the 23 International Mechanical Pulping Conferences (IMPC) between 1973 and 2018 showed that 97% of the variables described mechanical pulp as a continuum. Hence, only 3% of the variables reflected the heterogeneous nature of mechanical pulps. Many authors point out the benefits of describing the character of a material by as few and as independent properties as possible. In 1957, Steenberg stated: “Any valuable theory must be supposed to include a number of independent factors”. However, within the mechanical pulping area it is common practise to evaluate the character of pulp with respect to a wide range of more or less correlated measured pulp and fibre properties. In the review of the last 23 IMPCs we found that more than 96% of the variables examined in the articles where of that kind. In our efforts to describe a mechanical pulp with respect to its highly heterogeneous nature we have among others been inspired by Forgacs who worked with independent common factors in order to characterize mechanical pulps. He presented a paper in 1963 where he states that at least two independent factors are needed to describe a mechanical pulp. They reflect shape and length of the particles. Also Strand has inspired us with his work in the 80’s where he used factor analysis on a huge database to derive two independent common factors reflecting “bonding” (Factor 1) and “fibre length” (Factor 2). Examining a few independent common factors instead of several conventionally measured properties, which are more or less correlated, makes it easier to get an overview of the status of the processed material. Therefore, it is a little surprising that independent common factors constitute only 4% of the variables presented at the IMPCs since 1973. Strands approach was tested in a long-term evaluation in two mills. It was possible to produce a paper product more uniform in quality, compared to common practise. However, none of the above-mentioned independent factors reflects the heterogeneity of the pulp. Paper and pulp makers commonly agree that, within certain limits, uniformity is the most important characteristic of both the pulp and the paper. If we know how to perform uniformly, we may also be able to move into other operating areas (or volumes) in a controlled way. However, there is no common agreement on how to define "uniformity". Papermakers are still to a great extent specifying their demands on the pulp in terms of dewatering ability and average length-weighted fibre length although the correlation to product quality is vague and weak and varies over time. Almost since the advent of mechanical pulping processes, the operators have for process control had readings of dewatering ability of a pad consisting of billions of particles expressed as mL of water and average length-weighted fibre length of the pulp, which are far from being independent factors. Variations in any of these two properties may depend on variations in a combination of several more underlying factors. Therefore, it is hard to know what actions the operators should take to avoid running off spec. So far, the main development in the concept with dewatering and length to assist the operators have been firstly, to get time trends of these variables on a DCS screen instead of on a piece of paper in the control room, and secondly to get the readings more frequently with on-line analysers. During the same period, there have been an immense development of refiner concepts, fractionation, process design, modelling, use of raw material, fibre characterization, and new products. By putting more attention to reality and describing mechanical pulp as a heterogeneous material, which the mechanical pulps truly are, we hope to be able to get a more profound understanding how wood particles are developed along the process all the way to product. We also hope to give the operators in the mechanical pulping plant a more realistic description of the material they are supposed to deliver to the paper and board makers in order to facilitate their possibilities to produce a more uniform product quality at minimum cost. The aim of our presentation is to share some of our insights and reflections how to describe the heterogeneous nature of mechanical pulps to the mill operators.We have applied factor analysis on particle level based on measurements in an optical analyser of fibre diameter, fibre wall thickness, fibre length, and fibre fibrillation. Examples will be presented of how the raw material and the process have set characteristic fingerprints in terms of the distribution of an independent common bonding factor on particle level. It is fascinating to see how much that may be hidden behind averages, c.f. Rosling et al. (2018) who warn against comparing averages, which often obstruct a more profound understanding of a subject. In our presentation, we intend also to discuss how a description of the heterogeneity of the material may be used to get measures of energy efficiency of the process, separation efficiency of fractionation equipment, and how to link fibre characteristics to properties of products. Some reflections will also be shared on what we think is further required to get a more realistic description of the heterogeneous material we call mechanical pulp. Reference: Rosling H., Rosling Rönnlund A., Rosling O., (2018), ”Factfulness”, Natur & Kultur, ISBN 978-91-27-14994-6
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- Ferritsius, Olof, et al.
(författare)
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Process considerations and its demands on TMP property measurements - A study on tensile index
- 2017
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Ingår i: Nordic Pulp & Paper Research Journal. - 0283-2631 .- 2000-0669. ; 32:1, s. 45-53
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Tidskriftsartikel (refereegranskat)abstract
- As a vital component in the strive towards improved energy efficiency in the operation of TMP refining processes, this work highlights the importance of well- designed procedures when collecting and analysing pulp properties with respect to process conditions. Process data and pulp from a CD82 chip refiner have been used to show that tensile index has strong covariance with fibre residence time calculated by the extended entropy model. A combination of theoretical and practical analysis methods has shown that, in order to assure representative, reliable results, pulp sampling procedures should comprise composite pulp samples collected during a sampling period of about three minutes. In addition, at least four subsequently collected composite pulp samples should be included in the analysis to effectively dampen effects from fast process variations as well as from slow process drift. An in-depth study on tensile index measurements clarifies that 40-60 strips should be used in the case we studied regardless if machine made paper or handsheets are considered.
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| 8. |
- Eriksson, K., et al.
(författare)
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Benefits from improved stability in process conditions and pulp properties-a double disc refiner case study
- 2016
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Ingår i: International Mechanical Pulping Conference 2016, IMPC 2016. - : TAPPI Press. - 9781510830738 ; , s. 317-327
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Konferensbidrag (refereegranskat)abstract
- The purpose of this case study was to explore the potential for reduced energy consumption by improved process control. The application was HC post-refining of TMP in double-disc refiners. Based on data from both continuous production and from step-response tests, a thorough analysis of process performance was conducted. It was found that a significant proportion of the process disturbances, as reflected in the refiner motor load, could be successfully dampened through stabilizing measures on the basic control level. The remaining disturbances was found to be generated inside the refiner itself. In order for these disturbances to be dampened, measurements that can characterize the conditions inside the refining zone are necessary. Given the present design and instrumentation of the process, dynamic modelling of refiner motor load was performed and for fiber properties, muhivariate modeling methods were used to derive expressions for the independent variables Fl and F2. Taken together, evaluation of the models gave directions on how to further improve the process stability and indicated a potential for reduced energy consumption.
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| 9. |
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| 10. |
- Ferritsius, Olof, et al.
(författare)
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Average fibre length as a measure of the amount of long fibres in mechanical pulps - ranking of pulps may shift
- 2018
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Ingår i: Nordic Pulp & Paper Research Journal. - : Walter de Gruyter GmbH. - 0283-2631 .- 2000-0669. ; 33:3, s. 468-481
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of this study was to investigate the applicability of different ways of calculating the average fibre length based on length measurements of individual particles of mechanical pulps. We have found that the commonly used average length-weighted fibre length, which is based on the assumption that coarseness is constant for all particles, as well as the arithmetic average, may lead to erroneous conclusions in real life as well as in simulations when used as a measure of the amount of long fibres. The average length-length-weighted fibre length or a weighting close to that, which to a larger extent suppresses the influence of shorter particles, is a relevant parameter of the "length" factor, i. e. amount of long fibres. Our findings are based on three studies: refining of different assortments of wood raw material in a mill; data from LC refining in mill of TMP, including Bauer McNett fractionation; mixing of pulps with different fibre length distributions. If the acceptable average fibre length for different products can be lowered, the possibility of reducing the specific energy input in refining will increase. Therefore, we need a reliable and appropriate way to assess the "length" factor.
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