Journal articles on the topic 'Wood-pulp Refining'
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Li, Bin, Haiming Li, Quanqing Zha, Rohan Bandekar, Ahmed Alsaggaf, and Yonghao Ni. "Review: Effects of wood quality and refining process on TMP pulp and paper quality." BioResources 6, no. 3 (June 8, 2011): 3569–84. http://dx.doi.org/10.15376/biores.6.3.li.
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For the thermomechanical pulping (TMP) process both wood chip quality and the refining process have important effects on the resulting pulp and paper quality. Properties of wood raw material give a framework for final pulp properties. During TMP refining the specific energy consumption and refining intensity strongly impact fibre and pulp qualities. Increasing specific energy consumption benefits the development of fibres and improves their properties. However, high intensity refining tends to shorten the fibres and produces more fines content when compared with low intensity refining. This review focuses on the influence of key variables of chip qualities and the refining process on TMP pulp and paper qualities.
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Zanuncio, Antonio Jose Vinha, Amélia Guimarães Carvalho, Angelica de Cassia Oliveira Carneiro, Renato Augusto Pereira Damasio, Paulina Valenzuela, William Gacitúa, and Jorge Luiz Colodette. "PULP PRODUCED WITH WOOD FROM Eucalyptus TREES DAMAGED BY WIND." CERNE 22, no. 4 (December 2016): 485–92. http://dx.doi.org/10.1590/01047760201622042222.
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ABSTRACT Wind may damage eucalyptus trees, especially 24 months after planting, which can reduce wood fiber quality and hinder pulp production. The objective of this study was to evaluate the use of these materials in mixtures with wood from seven-year-old trees to produce pulp. Bleached pulp was produced using 100, 95, 85, 75 and 0% wood from seven-year-old eucalyptus trees, related to cutting age. Wood from two-year-old trees, when trees are most susceptible to damage by wind, completed each treatment. A 5 cm thick disc was taken from breast height (1.3m) on each tree for anatomical and ultrastructural characterization. The seven-year-old wood had lower vessel frequency and fibers with a longer length, higher cell wall fraction, higher modulus of elasticity and hardness, and a lower microfibril angle. Pulp refining decreased the opacity and specific volume, increased air resistance and improved mechanical properties. The addition of two-year-old wood to produce pulp reduced the mechanical properties and opacity, and increased the air resistance of the paper. The proportion of two-year-old wood that can be used in pulp production varied with the clone, parameter, and refining level. However, the pulp produced with 5% wood from two-year-old trees and 95% wood from seven-year-old trees was similar to that with 100% seven-year-old wood. Therefore, 5% two-year-old wood can be used to produce pulp without quality losses.
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HART, PETER W., DARRELL M. WAITE, LUC THIBAULT,, JOHN TOMASHEK, MARIE-EVE ROUSSEAU, CHRISTOPHER HILL, and MARC J. SABOURIN. "Refining Energy Reduction and Pulp Characteristic Modification of Alkaline Peroxide Mechanical Pulp (APMP) Through Enzyme Application." May 2009 8, no. 5 (June 1, 2009): 19–25. http://dx.doi.org/10.32964/tj8.5.19.
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Eucalyptus wood chips were subjected to impregnation with various blends of novel fiber modify-ing enzymes before chemical pretreatment and two stages of refining using the preconditioning refiner chemical–alkaline peroxide mechanical pulping (PRC-APMP) process. Wood chip impregnation and pulp processing was con-ducted at a pilot plant in the United States. When compared under constant chemical application and at a constant 350 mL CSF, enzyme treatment reduced specific refining energy by at least 24%. The effect of one versus two stages of impregnation and of enzyme action upon several physical pulp properties was determined.
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Greenwood, M. S., P. D. Panetta, L. J. Bond, and M. W. McCaw. "Ultrasonic sensor to characterize wood pulp during refining." Ultrasonics 44 (December 2006): e1123-e1126. http://dx.doi.org/10.1016/j.ultras.2006.07.008.
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Vikharev, S. N., and VA Morkovin. "Research of the drawing of bars plate in the refiners." Journal of Physics: Conference Series 2094, no. 4 (November 1, 2021): 042038. http://dx.doi.org/10.1088/1742-6596/2094/4/042038.
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Abstract Object of research of article is the drawing of bars plate in the refiners at refining of chips and wood pulp. On the basis of the theory of contact interaction of bars influence of the drawing of plate on characteristics of contact processes is investigated. The friction coefficient between plate decreases at increase in density of contact of bars. At increase in an angle of crossing of bars rotor and stator and refining of pulp with concentration up to 6% the coefficient of friction decreases. At increase in an angle of crossing of bars chips and pulp with concentration over 10% the coefficient of friction increases. Therefore it is recommended to increase the angle of crossing of bars rotor and stator at refining of pulp of low concentration, and at refining of pulp of concentration over 10% and chips - to reduce, up to a radial arrangement.
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de Assis, Tiago, Joel Pawlak, Lokendra Pal, Hasan Jameel, Richard Venditti, Lee W. Reisinger, Dale Kavalew, and Ronalds W. Gonzalez. "Comparison of wood and non-wood market pulps for tissue paper application." BioResources 14, no. 3 (July 8, 2019): 6781–810. http://dx.doi.org/10.15376/biores.14.3.6781-6810.
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A comparison among ten market pulps at a laboratory scale using uncreped tissue handsheets was performed to study the performance of wood and non-wood pulps for tissue manufacturing, evaluate what fiber features are desired for a specific tissue property, and determine how non-wood pulps can be used to replace or complement wood pulps in tissue products. A characterization of the fiber morphology and handsheet properties (softness, water absorbency, and strength) was performed at different mechanical refining levels. The results showed that the fiber morphology had a major impact on tissue properties. Market pulps with a combination of long fibers, high coarseness, and low fines content can provide superior bulk and water absorbency. Short fibers with thin cell walls and low fines content can impart superior softness. Bleached bamboo soda pulp can replace hardwood and softwood pulps to provide an excellent combination of water absorbency and strength. Bleached bamboo soda pulp can also replace Northern bleached softwood kraft (NBSK) pulp to impart strength without sacrificing softness. Bleached and semi-bleached wheat straw soda pulps presented a similar combination of softness and strength as Southern bleached hardwood kraft (SBHK) pulp. The wheat straw pulps can be used to replace deinked pulp (DIP) pulp to impart intermediate levels of water absorbency and strength.
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Kojima, Yasuo, Shinichi Isaji, Seung-Lak Yoon, and Toshihiro Ona. "Selection criteria of Eucalyptus globulus Labill. for production of chemithermomechanical pulps (CTMP)." Holzforschung 62, no. 1 (January 1, 2008): 71–76. http://dx.doi.org/10.1515/hf.2008.010.
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Abstract Utilization of rapidly growing trees, such as eucalypts, for high-yield mechanical pulps is limited by low brightness owing to high contents of alkali and neutral extractives. Wood supply problems have developed in many areas of the world and new sources of high-yield pulp are needed. Ten Eucalyptus globulus trees were selected from two plantation sites to evaluate suitability as raw material for high-quality and high-yield pulp. Chemithermomechanical pulp (CTMP) was prepared from tree chips pretreated with sodium sulfite prior to refining. Characteristics of the CTMP were correlated with chemical and physical properties of the wood. There was a linear relationship between the content of alcohol-benzene extractives in wood and CTMP brightness. Klason lignin content in wood was inversely correlated with pulp sheet density, which is an important characteristic affecting the physical properties of pulp. The content of alkali extractives were inversely correlated with pulp yields. Color reversion was tested by exposing CTMP sheets to heat and light. Heat-induced yellowing of CTMP was of a low level and satisfied requirements for printing paper. The rate of yellowing was inversely associated with extractives and can be reduced by antioxidants.
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Vidaurre, Graziela Baptista, Miguel Pereira, Walter Torezani Neto Boschetti, Rudolf Patt, Jorge Luiz Colodette, Benedito Rocha Vital, and Maria Naruna Felix de Almeida. "NSSC pulping of fast growing trees." Nordic Pulp & Paper Research Journal 33, no. 3 (September 25, 2018): 404–13. http://dx.doi.org/10.1515/npprj-2018-3044.
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Abstract Neutral sulphite semichemical pulping (NSSC) of Schizolobium amazonicum (Paricá), a fast-growing Amazonian tree, was compared with that of Eucalyptus grandis (eucalypt), one of the most important wood sources for the Brazilian pulp industry, and with mixtures of both woods in different proportions (mix). Wood chips prepared from 7-year old trees were steamed, cooked using the NSSC process and defibered in a 12” disc refiner in three stages. The paricá wood produced pulp of lower yield (75 %) than eucalypt (77 %) at 16 % sulfite/150 min/170 °C. The paricá and eucalypt pulps were bleached to about 68 and 74 % ISO brightness, respectively, by the QPFAS sequence. Paricá consumed more energy for refining in comparison with the eucalypt wood. The wood mix produced lower yield and brightness than the single species processed separately.
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Gorski, Dmitri, Jan Hill, Per Engstrand, and Lars Johansson. "Review: Reduction of energy consumption in TMP refining through mechanical pre-treatment of wood chips." Nordic Pulp & Paper Research Journal 25, no. 2 (May 1, 2010): 156–61. http://dx.doi.org/10.3183/npprj-2010-25-02-p156-161.
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Abstract This review covers the effect of mechanical pre-treatment of wood chips on the energy consumption in refining and the quality of pulp. To understand the mechanisms of mechanical pre-treatment, a short description of relevant refining theory and reported effects of pre-treatment on wood morphology is given. Mechanical pre-treatment offers a chance to utilize the energy needed to defibrate chips in a more efficient way, minimizing the cyclic elastic deformations which are the main defibration mechanism in refining. Studies of fibre morphology indicate that compressive pretreatment mechanically introduces favorable weak points in the S1 and S2 fibre walls where defibration proceeds easier upon subsequent refining. Published results which cover the effect of the pretreatment on energy consumption and pulp properties are reviewed. Energy reduction of between 10% and 30% is reported in the literature. High ratio of volumetric compression is necessary. Pressurized conditions are required to ensure that the fibres are not damaged during the pre-treatment. Other effects of compressive pretreatment include a more uniform chip size and moisture content, better penetration of chemicals and removal of extractives from the chips. A list of equipment used for chip pre-compression is provided together with published results of pilot-scale and mill-scale operation.
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Fahlén, Jesper, and Lennart Salmén. "Ultrastructural changes in a holocellulose pulp revealed by enzymes, thermoporosimetry and atomic force microscopy." Holzforschung 59, no. 6 (November 1, 2005): 589–97. http://dx.doi.org/10.1515/hf.2005.096.
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Abstract To increase our knowledge of the ultrastructure within softwood fibres, enzymatic treatment, thermoporosimetry, light microscopy, and atomic force microscopy with image analysis were used to investigate the structure of holocellulose softwood pulp fibres. The size of the average cellulose fibril aggregates and the width of pore and matrix lamellae were found to be uniform across the secondary cell-wall layer in the transverse direction of the wood fibre wall. In holocellulose, these dimensions were very similar to those in the native wood, whereas in kraft pulp the cellulose fibril aggregates were larger and the pore and matrix lamellae broader. These differences between holocellulose and kraft pulp fibres suggest that a high temperature is needed for cellulose fibril aggregation to occur. Neither refining nor drying of the holocellulose pulp changed the cellulose fibril aggregate size. Upon drying and enzymatic treatment, a small decrease in the pore and matrix lamella width was evident throughout the fibre wall. This indicated not only uniform distribution of pores throughout the fibre wall, but also enzymatic accessibility to the entire fibre wall. The holocellulose pulp had a somewhat larger pore volume than the kraft pulp. Refining of the holocellulose pulp led to pore closure, probably due to increased mobility of the fibre wall. The enzymatic treatment revealed that during hydrolysis of one hemicellulose, part of the other was also dissolved, indicating that the two hemicelluloses are to some extent linked to each other in the structure.
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Pelletier, Andre, Kecheng Li, Yu Zhao, George Court, James Luo, and Mark Frith. "Improvement of enzyme transport in wood chips for thermomechanical pulp refining." Carbohydrate Polymers 95, no. 1 (June 2013): 25–31. http://dx.doi.org/10.1016/j.carbpol.2013.02.025.
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Kazymov, Dmitriy Sergeyevich, Lyudmila Gertsevna Makhotina, Андрей Борисович Nikandrov, Anton Gennad'yevich Kuznetsov, and Эдуард Львович Akim. "FEATURES OF LARIX SIBIRICA LEDEB WOOD PROCESSING INTO HIGH YIELD FIBROUS SEMI-FINISHED PRODUCTS." chemistry of plant raw material, no. 1 (March 16, 2021): 317–25. http://dx.doi.org/10.14258/jcprm.2021018472.
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About 40 % of the forest area in the Russian Federation is occupied by larch trees growing in the southern regions of Eastern Siberia and the Far East, where existing and reconstructed woodworking enterprises are located. In this regard, the use of larch wood in the production of fibrous semi-finished products is an urgent task for the Russian forest complex. As is known, larch wood contains a large number of extractive substances that have a significant impact on the process of its deep chemical processing. Therefore, it can be assumed that the production of wood (mechanical) pulp from larch wood, in particular chemical-thermomechanical pulp (CTMP), will be very effective, but with its own specific features. In this paper, it is proposed to modify the technology by using enzymes – protein catalysts of various reactions. The purpose of this study is to determine the potential of using larch wood enzymatic treatment in CTMP-technology, to evaluate the effect of enzymes on the physical and mechanical parameters of the fiber and the specific energy consumption during refining. Industrial samples of Larix sibirica Ledeb (Pinaceae) wood chips were used to obtain CTMP. Five commercially available enzymatic agents were used to treat wood chips. CTMP was obtained using laboratory equipment that simulates the industrial stages of production. Enzymatic treatment of larch wood has shown an improvement in the technological parameters of CTMP production, namely, a decrease in the specific energy consumption for refining and an increase in the quality of finished products.
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Sandberg, Christer, Erik Nelsson, Birgitta A. Engberg, Jan-Erik Berg, and Per Engstrand. "Effects of chip pretreatment and feeding segments on specific energy and pulp quality in TMP production." Nordic Pulp & Paper Research Journal 33, no. 3 (September 25, 2018): 448–59. http://dx.doi.org/10.1515/npprj-2018-3052.
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Abstract 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.
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Nlombi, K., and Z. Koran. "Les caractéristiques papetières du bois attaqué par la tordeuse des bourgeons de l'épinette." Canadian Journal of Forest Research 19, no. 8 (August 1, 1989): 986–91. http://dx.doi.org/10.1139/x89-151.
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Chemithermomechanical pulp was manufactured from a supply of budworm-killed balsam fir wood in a pilot plant at the Université du Québec. The physical properties of these pulps were evaluated according to the standard methods of the Canadian Pulp and Paper Association and compared with those of a corresponding sample of experimental pulp prepared from a supply of sound balsam fir wood under the same experimental conditions. It was found that the trees killed 3 years before they were cut produced significant reductions in tear strength (50%), breaking length (25%), burst (24%), and in its brightness (4.5%). The decreases were accompanied by a corresponding increase in the opacity of the sheet (5%) and a significant decrease in energy consumption (15%), the latter representing an important reduction in the electric energy cost of refining. Since in practice budworm-killed wood is always used in some blends with sound wood, the reductions in tear and tensile properties will be directly proportional to the proportions of each type of wood. Thus, in a 50/50 blend of chips made up of sound wood and budworm-killed wood, the burst strength is reduced only by 12%, but at the same time the decrease in the electric bill is also cut in half. Thus, if the budworm-killed forest is harvested not later than 3 years after the trees have been killed, the utilization of this wood in the pulp and paper industry is more promising than we were led to believe in the past.
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Лебедев (Lebedev), Иван (Ivan) Владимирович (Vladimirovich), Яков (Yakov) Владимирович (Vladimirovich) Казаков (Kazakov), Дмитрий (Dmitrij) Германович (Germanovich) Чухчин (Chukhchin), and Кристина (Kristina) Александровна (Аleksandrovna) Романенко (Romanenko). "THE ROLE OF FIBERS SURFACE IN DEVELOPMENT OF PAPERMAKING PROPERTIES OF TECHNICAL PULP IN THE REFINING PROCESS." chemistry of plant raw material, no. 2 (January 15, 2018): 207–16. http://dx.doi.org/10.14258/jcprm.2018022248.
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The aim of this work was to determine the relationship between the values of the fiber specific surface and papermaking properties of the pulp that are changing in the refining process. Quality data on the status and quantitative data on the value of the fibers specific surface for softwood and hardwood kraft pulp with different lignin content and different degree of refining were obtained. When preparing samples was used technology of cryofixation and freeze-drying the wet laboratory samples. The SEM-images of the cellulose fibers surface in the state such as for the sheet forming, obtained on scanning electron microscope ZEISS "SIGMA VP". The SEM-images shows just noticeable difference in development of the fibers surface in the beating process. This is manifested in an increase in the number of microfibrils on the fiber surface. Quantitative data were obtained on the automatic analyzer of the specific surface magnitude ASAP. A visually apparent increase of the surface when beating technical cellulose confirmed quantitatively. The value of the specific surface area increased from 2 m2/g for cellulose after the dispergation into pulp of up to 4...6 m2/g after refining up to 60 °SR. Removal of lignin from cellulose promotes more intensive development of the surface during refining.For different kinds of pulp, similar dependences of physical-mechanical properties (interfiber bonding forces, bulk density, modulus of elasticity) of laboratory samples and specific surface data, which change during refining, are established.The main influence on the change in the structural-dimensional and elastic properties of paper during refining is exerted by an increase in the content of microfibrils on the outer surface of the fibers. The tightness of the correlation and the nature of the observed dependence depends on the wood species from which the cellulose is derived, on the lignin content of the samples, and on the drying method. For softwood pulp, the tightness of the relationship is higher than for hardwood pulp.
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Sansígolo, Cláudio Angeli, and Éder da Silva Ramos. "Quality of wood and pulp from a clone of Eucalyptus grandis planted at three locations." CERNE 17, no. 1 (March 2011): 47–60. http://dx.doi.org/10.1590/s0104-77602011000100006.
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Eucalyptus grandis is one of the most popular species to use as raw material for pulp production in Brazil, as it provides excellent pulping, bleaching and papermaking results. The main objective of this study is to examine the quality of wood and pulp from a clone of Eucalyptus grandis, at age 4 years approximately, planted in three different soils, two of which being low fertility and one being a superior fertility soil, and their reflections on wood quality and pulping results. Chemical analyses of the soils followed guidelines developed by Raij et al. (2001), while physical and chemical properties of the wood followed ABTCP, TAPPI and ABNT standards. Chemical analyses of the soils pointed to lower fertility in Fazenda Limeira and Fazenda Tapera Queimada as opposed to higher fertility in Fazenda Mendes União. Results revealed stronger tendencies for the stand grown in the less fertile soils (Fazenda Limeira and Fazenda Tapera Queimada) in comparison to the stand grown in more fertile soil (Fazenda Mendes União) as to: higher wood and bark basic density, lower height and dry matter content, higher bark content, lower extractives content and higher holocellulose content, higher total and screened yields from pulping, lower specific wood consumption/t of pulp, and higher tear and tensile indices at low refining levels.
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Fernando, Dinesh, Dino Muhić, Per Engstrand, and Geoffrey Daniel. "Fundamental understanding of pulp property development under different thermomechanical pulp refining conditions as observed by a new Simons’ staining method and SEM observation of the ultrastructure of fibre surfaces." Holzforschung 65, no. 6 (October 1, 2011): 777–86. http://dx.doi.org/10.1515/hf.2011.076.
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AbstractThe morphological and chemical characteristics of cell walls govern the response of wood fibre to mechanical pulping processes and thereby influence the energy efficiency of the process and determine most pulp and paper properties. A study has been carried out at the microstructural/ultrastructural level of fibre cell walls by means of a newly developed Simons’ staining (SS) method and scanning electron microscopy to characterize thermomechanical pulps (TMPs) produced under different refining conditions. The SS method allows assessment and quantification of pulp fibre development during the process in terms of cell wall delamination/internal fibrillation (D/IF) under different process conditions, and the degree of D/IF can be statistically evaluated for different TMP types. In focus was never-dried Norway spruce TMP from primary stage double-disc refining running in a full-scale mill, where specific refining energy was varied at different refining pressure levels. Improved energy efficiency was gained at the same tensile index level when applying high pressure (temperature). Under conditions of high pressure and refining energy, a significant enhancement of the degree of D/IF of pulp fibres was observed. The surface ultrastructure of these fibres exhibited an exposed S2 layer with long ribbon-type fibrillation compared to pulps produced with lower pressure and energy input. A given TMP type can be classified in the categories of high-severity and low-severity changes and quasi-untreated concerning the degree of D/IF of its fibres. The relative proportions of these are important for the development of pulp properties such as tensile strength. The presence of higher amounts of fibre fractions in the categories high D/IF and low D/IF will improve the tensile index of a TMP.
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Reyes, Pablo, André Ferraz, Miguel Pereira, Jaime Rodríguez, and Regis Teixeira Mendonça. "Chemithermomechanical and kraft pulping of Pinus radiata wood chips after the hydrothermal extraction of hemicelluloses." Holzforschung 69, no. 1 (January 1, 2015): 33–40. http://dx.doi.org/10.1515/hf-2013-0235.
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Abstract Pinus radiata D. Don wood chips were submitted to a hydrothermal (HT) process, which is a pretreatment with pressurized water at P-factors of 20 (E1) and 1200 (E2), leading to 27% and 56% of hemicellulose removal, respectively. The residual wood chips were pulped by the chemithermomechanical (CTMP) and kraft processes. The pulp yield in the HT/CTMP process was in the range of 56–75%. The cellulose yields were not affected by the HT pretreatment, whereas the solubilization of hemicelluloses and lignin was intensified. The HT process provided energy savings in the refining of CTMP pulps, and the E1/CTMP pulp had a similar tensile and increased tear strength as the control wood. For kraft pulping, the HT wood chips demanded more active alkali (AA) to achieve a κ number (KN) of 30, and consequently, a decrease in pulp yield was observed (47.2% yield in the control and 44.4% and 37.8% in the E1 and E2 pulps, respectively). The fiber length decreased in the E1 and E2 kraft pulps compared with their control samples. In the E1 pulps, the tensile, tear, and burst indexes decreased by 10%, 25%, and 30%, respectively. Considering the low hemicellulose content and pulp viscosity in the range of 800–900 ml g-1, the mild HT process of P. radiata would be better suited for preparing cellulose-rich materials instead of paper-grade pulps under the biorefinery concept.
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Kovaleva, K. I., V. V. Gorshkov, D. S. Gerasimov, M. G. Mikhaleva, D. N. Vtyurina, G. G. Politenkova, S. N. Nikol’sky, and S. V. Stovbun. "A method of physicochemical treatment of the wood pulp based on cold refining." Industrial laboratory. Diagnostics of materials 85, no. 2 (March 1, 2019): 33–37. http://dx.doi.org/10.26896/1028-6861-2019-85-2-33-37.
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HUANG, FANG, and ARTHUR RAGAUSKAS. "Integration of hemicellulose pre-extraction in the bleach-grade pulp production process." October 2013 12, no. 10 (November 1, 2013): 55–61. http://dx.doi.org/10.32964/tj12.10.55.
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Loblolly pine woodchips were first pre-extracted with 6 wt% (percent on original nonextracted o.d. wood weight) sodium hydroxide at room temperature overnight, then treated at 90°C for 90 min, following another 4 h extraction with the addition of 5 wt% boric acid to partially remove hemicellulose. During the subsequent bleach-grade kraft pulping process, the cooking intensity was alleviated, either by decreasing the cooking time (reduced H-factor by 35%) or decreasing the chemical charge by 30%, with the objective of obtaining similar pulp quality as the control cook. After elemental chlorine free bleaching and PFI refining, the results indicated that the pre-extracted pulp could maintain equal or similar brightness and physical strength as the control pulp through this optimization of the pulping process.
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Longue Júnior, Dalton, Jorge Luiz Colodette, Gabriel de Castro Baião Brumano, Edson Domingos da Silva, and Marcos Maurici Araújo Alves. "Effect of process variables on quality improvement of TGW pulps of Eucalyptus." CERNE 19, no. 4 (December 2013): 567–74. http://dx.doi.org/10.1590/s0104-77602013000400006.
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High-yield pulps are usually derived from pine wood on account of its anatomical configuration and technology used. Eucalyptus, on the other hand, is a fast-growing species, abundant in many parts of the world, and has thus emerged as an alternative source for many products in the pulp and paper industry. In this particular study, high-yield pulps of Eucalyptus grandis were used. In order to improve their properties, pulps were subjected to chemical treatments with different doses of sodium hydroxide prior to refining (0, 30, 50 and 70 kg/t), at 75ºC temperature, 3% consistency, during 1 minute. The refining process was done in a Bauer disc refiner (Regmed) using various refining times (0, 5, 10 and 15 minutes). Results showed that refining with addition of NaOH did bring significant gains to the eucalyptus fibers regarding strength properties, the dose 50 kg/t being found the most suitable. However, other variables associated with refining could also be modified to further improve the strength properties of eucalyptus pulps, including consistency and refining discs configuration.
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Hellström, Lisbeth M., Per A. Gradin, Per Engstrand, and Øyvind Gregersen. "Properties of wood chips for thermomechanical pulp (TMP) production as a function of spout angle." Holzforschung 65, no. 6 (October 1, 2011): 805–9. http://dx.doi.org/10.1515/hf.2011.087.
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Abstract Spruce wood chips were produced under well-controlled conditions in a laboratory wood chipper at spout angles of 30°, 40°, and 50° at a cutting rate of 20 m s-1 and with a nominal chip length of 25 mm. The chips were then refined under thermomechanical pulp (TMP) conditions in a pilot refiner plant. The pulp properties 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 the wood 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.
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Teixeira, Divino Eterno. "Recycled Old Corrugated Container Fibers for Wood-Fiber Cement Sheets." ISRN Forestry 2012 (March 14, 2012): 1–8. http://dx.doi.org/10.5402/2012/923413.
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Recycled pulp of old corrugated containers (OCCs) was studied as a possible fiber source for wood-fiber cement (WFC) sheets. This industry currently largely relies on kraft pulp, an expensive fiber source. Thus, WFC sheets were made using less costly OCC fibers utilizing various types of treatments including fiber fractionation (FF) and refining to 500 and 400 Canadian Standard Freeness (CSF) to determine the effect of these treatments on the sheets strength. Unprocessed virgin kraft fiber of radiata pine (Pinus radiata) was used as control for comparison purposes. The unprocessed OCC pulp furnish yielded an initial freeness of 635 CSF; after fractionating, however, it was increased to 754 CSF. OCC pulp presented a kappa number of 47, compared to 23.7 for P. radiata. Fractionating OCC pulp was effective in raising the range of long fibers in the stock from 68 percent to 85 percent, before and after fractionating, respectively. Results from WFC sheets made in laboratory showed that there was no significant difference in board strength among boards made with unprocessed OCC fibers, fractionated and refined OCC, and P. radiata fibers. However, sheet strength decreased when refined OCC fibers were used. The results suggest that OCC fibers can produce WFC sheets with desirable characteristics compared to those of unrefined virgin kraft fiber of P. radiata.
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Bergqvist, Göran, Urban Bergsten, and Bo Ahlqvist. "Fibre properties of Norway spruce of different growth rates grown under birch shelterwoods of two densities." Canadian Journal of Forest Research 30, no. 3 (March 1, 2000): 487–94. http://dx.doi.org/10.1139/x99-235.
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The effects of birch shelterwood density (0, 300, and 600 trees/ha) and growth rate on fibre and pulp properties of Norway spruce (Picea abies (L.) Karst.) understorey (growing at 1500 trees/ha) were evaluated for a trial in the boreal coniferous forest, 58 years after establishment of the stand and 21 years after establishment of the trial. Microdensitometry was used to record variations in wood density, whereas fibre properties and kraft pulp strength properties were measured on laboratory-made batches of unbleached kraft pulp. The main conclusion of the investigation is that a birch shelterwood has only a minor influence on the wood and fibre properties of sheltered Norway spruce and that the resulting consequences for kraft pulping are moderate. Length-weighted mean fibre length was significantly affected only by growth rate. It was 1.75 mm, or 6-13% lower, for trees showing a low growth rate than for all other trees. Tensile index was already high before refining, 85-95 Nm g-1, and the increase due to beating was similar for all shelterwood densities and growth rate classes. At 2000 beating revolutions, there was a strong negative correlation between tear index and the proportion of fibres shorter than 0.20 mm. The volume of wood required to produce 1 t of kraft pulp was almost identical, 5.4 ± 0.1 m3 t-1, for sheltered and unsheltered spruce. Norway spruce growing without shelter produced more pulp per hectare in all fibre length classes, but the difference was greatest, 56-59% compared with sheltered spruce, for the longest fibres (i.e., longer than 3 mm).
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RUNGE, TROY, CARL HOUTMAN, ALBERTO NEGRI, and JACKIE HEINRICHER. "Timber bamboo pulp." TAPPI Journal 12, no. 2 (March 1, 2013): 9–15. http://dx.doi.org/10.32964/tj12.2.9.
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Fast-growing biomass, such as bamboo, has the potential to serve an important future role in the pulp and paper industry with potential to both lower resource costs and improve a product’s sustainability. Moso bamboo is particularly interesting due to its fast growth and size, which allows it to be handled and chipped similarly to wood resources. In this study, we will share results of the chip preparation, kraft cooking, and ECF bleaching of this bamboo species and compare its pulpability, bleachability, and physical properties to a fast growing hybrid poplar tree. Results indicate that the bamboo chips cooked and bleached similarly to the poplar hardwood, allowing for co-cooking. The resulting pulps had superior tensile properties at low refining, but did have higher fines that lowered drainability as measured by Canadian Standard Freeness. The bamboo fiber morphology was also measured, indicating the fiber to have length weighted average fiber lengths and coarseness values to be greater than the poplar wood studied, which should allow this material to be used in many paper grades.
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Małachowska, Edyta, Marcin Dubowik, Aneta Lipkiewicz, Kamila Przybysz, and Piotr Przybysz. "Analysis of Cellulose Pulp Characteristics and Processing Parameters for Efficient Paper Production." Sustainability 12, no. 17 (September 3, 2020): 7219. http://dx.doi.org/10.3390/su12177219.
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For economic reasons, increasing the use of various fibrous pulps with high lignin contents—i.e., chemothermomechanical pulp (BCTMP and CTMP), thermomechanical pulp (TMP), and semichemical pulp—is desirable. The relatively good quality and increased efficiency of these pulps make them attractive paper semi-products. In particular, they could alleviate the severe shortage of paper semi-products. Although mechanical pulp and semichemical pulp are achieving increasing quality with substantially increased wood efficiency, their production is often characterised by high consumption of electricity to defibre chips or refine high-lignin-content fibrous pulps. Technological, environmental, and economic evaluations of the manufacture and application of increased efficiency cellulose pulps that take into account potential profits from increased cellulose pulp efficiency and losses due to energy costs and degradation in the properties of the resulting paper are relevant and essential to paper mills. This article reports such an analysis. The authors have analysed the usable properties of ten cellulose pulps with various degrees of digestion and identified the optimum pulp that yields the optimum product properties, considering the yield; pulp refining time, which determines the cost of paper manufacture; and strength properties of the obtained paper.
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YOON, SUNG-HOON, MEHMET SEFIK TUNC, and ADRIAAN VAN HEININGEN. "Near-neutral pre-extraction of hemicelluloses and subsequent kraft pulping of southern mixed hardwoods." January 2011 10, no. 1 (February 1, 2011): 7–15. http://dx.doi.org/10.32964/tj10.1.7.
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Southern mixed hardwood chips were extracted with alkaline solutions at different chemical charges, times (45-110 min), and temperatures (125°C-160°C). At high alkali charges (10% and 20% sodium hydroxide [NaOH] as sodium oxide [Na2O]), the extract was strongly alkaline (pH about 13) and 17%-40% of the wood was dissolved. Subsequent kraft cooking of the extracted chips yielded 5%-7% less pulp than that of control kraft pulps. However, at reduced alkali charge, just sufficient to approximately neutralize the acids released during pre-extraction, the pulp yield (on original wood) after subsequent kraft pulping was not affected. In this case, about 5%-10% of the wood substance is removed during pre-extraction with 3% NaOH or 3% green liquor (+0.05% anthraquinone) at 140°C and 160°C for 60, 90, and 110 min. The green liquor extract obtained after 110 min at 160°C contained 2.1% (oven-dry weight basis) of sugars, 2.1% acetic acid, and 1.6% lignin accounting for 64% of the wood weight loss. Kraft pulping of the pre-extracted wood chips performed at 12% effective alkali charge showed significantly improved delignification rates and approximately the same or slightly higher yield than the kraft control at 15% effective alkali. The near-neutral green liquor+anthraquinone pre-extraction kraft pulps showed lower refining response but higher tear resistance and similar tensile strength compared to control kraft pulps.
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Hunt, C., W. Kenealy, E. Horn, and C. Houtman. "A biopulping mechanism: Creation of acid groups on fiber." Holzforschung 58, no. 4 (July 7, 2004): 434–39. http://dx.doi.org/10.1515/hf.2004.066.
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Abstract We investigated how biopulping modifies chemical and physical properties of wood and how these changes affect the properties of the resulting fiber. Mechanical and chemical testing revealed wood cell changes during 2 weeks of colonization by Ceriporiopsis subvermispora. Typical mechanical properties, such as modulus of elasticity and maximum load, tracked reductions in energy needed for mechanical refining to pulp. The data indicate the fiber saturation point of spruce increased from 29% to 42% during biopulping. At the same time, titratable acid groups increased up to 62%. Chemical analysis showed that oxalic acid esters were produced in the wood during biopulping in sufficient amounts to account for the increase in acid groups. The benefits of biopulping—energy savings and increased handsheet strength—as well as other physical property changes are consistent with the mechanism we propose: biopulping increases the acid group content of wood.
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Lloyd, John A., and Karl D. Murton. "Preparation of prehydrolysis-TMPs with different severity factors and analysis of the pulps and byproducts." Holzforschung 70, no. 11 (November 1, 2016): 1003–13. http://dx.doi.org/10.1515/hf-2015-0216.
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Abstract Thermomechanical pulps (TMPs) were prepared from Pinus radiata D. Don wood chips at pilot scale with application of different preheating severities. The hydrolysis products were separated at the compression screw feeding of the prehydrolysed chips into the refiner. Prehydrolysis of chips with steam at severity factor (SF) 3.5 reduced the refining energy (at 200 CSF freeness) by 36% when compared with the TMP control; however, the pulp quality was unacceptable. In contrast, pulps produced by SF 3.1 at 155°C have physical properties similar to the TMP control, but the energy saving is only 12%. Prehydrolysis darkens wood fibres making pulps unsuitable for printing and writing papers. However, it was demonstrated that the brightness may be recovered via conventional alkaline peroxide brightening. Pulp yield is lower but this disadvantage is offset by the availability of a pressate flow rich in hemicelluloses and hemicelluloses derived sugars in high concentrations that has good potential for conversion to new products. Impregnation of chips with citric acid (CA) during normal TMP processing was also investigated. Although refining energy was lower with CA treatment, the amount of extracted hemicelluloses was too small to be commercially useful. The prehydrolysis-TMP process may be of interest to financially constrained TMP mills provided that: (1) the process configuration is suitable for retrofitting an extended preheating stage with compression screw and (2) the extracted hemicelluloses can be converted to products of higher value than TMP.
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Mutjé, P., M. A. Pèlach, F. Vilaseca, J. C. García, and L. Jiménez. "A comparative study of the effect of refining on organosolv pulp from olive trimmings and kraft pulp from eucalyptus wood." Bioresource Technology 96, no. 10 (July 2005): 1125–29. http://dx.doi.org/10.1016/j.biortech.2004.10.001.
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Rusu, Marius, Kathrin Mörseburg, Øyvind Gregersen, Asuka Yamakawa, and Sari Liukkonen. "Relation between fibre flexibility and cross-sectional properties." BioResources 6, no. 1 (January 10, 2011): 641–55. http://dx.doi.org/10.15376/biores.6.1.641-655.
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The correlation between the fibre flexibility and cross-sectional area moment of inertia of thermomechanical pulp fibres was investigated. The main effects of refining were found to be internal fibrillation, external fibrillation, and fibre shortening. Internal fibrillation increases fibre flexibility and fibre collapsibility, improving fibre-to-fibre contact in a paper sheet. The raw materials used were pulps produced from six different Norway spruce logs and six different Scots pine logs, chosen in a manner that allowed variation of fibre wall thickness and fibril angle independently. Each wood sample was refined in four stages using a pressurized 12″ Sprout Waldron single disc refiner. Fibre flexibility was assessed by FiberMaster bendability measurements. Fibre bendability was measured on the +48 Bauer McNett fractions of the twelve 2nd, 3rd, and 4th stage thermomechanical pulps (TMP). The fibre cross-sectional samples were imaged using scanning electron microscopy (SEM). An image analysis method to calculate the area moment of inertia of each fibre using numerical integration was developed. Fiber bendability increased with specific energy consumption for both wood species (spruce and pine) from the 2nd refining stage to the fourth refining stage. Spruce had a higher rate of bendability increase than pine upon refining. It was expected that fibres with a low area moment of inertia would result in higher bendability, but no such correlation was found for either spruce or pine. Fibre bendability increased with internal fibrillation, as assessed from Simons staining. These results imply that local damage of the fibre wall such as delaminations, kinks, and compressions was the main effect in increasing the flexibility through refining of TMP.
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Ferritsius, Olof, Rita Ferritsius, Mats Rundlöf, Sofia Reyier Österling, and Birgitta A. Engberg. "Heterogeneity of thermomechanical and chemi-thermo-mechanical pulps described with distributions of an independent common bonding factor on particle level." BioResources 17, no. 1 (December 8, 2021): 763–84. http://dx.doi.org/10.15376/biores.17.1.763-784.
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Particles in mechanical pulp show a wide variety but are commonly described using averages and/or collective properties. The authors suggest using distributions of a common bonding factor, BIND (Bonding INDicator), for each particle. The BIND-distribution is based on factor analysis of particle diameter, wall thickness, and external fibrillation of several mechanical pulps measured in an optical analyser. A characteristic BIND-distribution is set in the primary refiner, depending on both wood and process conditions, and remains almost intact along the process. Double-disc refiners gave flatter distributions and lower amounts of fibres with extreme values than single-disc refiners. More refining increased the differences between fibres with low and high BIND. Hence, it is more difficult to develop fibres with lower BIND. Examples are given of how BIND-distributions may be used to assess energy efficiency, fractionation efficiency, and influence of raw material. Mill scale operations were studied for printing-grade thermomechanical pulp (TMP), and board-grade chemi-thermomechanical pulp (CTMP), both from spruce.
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Hernández, Manuel, M. Jesus Hernández-Coronado, M. Isabel Pérez, Esteban Revilla, Juan C. Villar, Andrew S. Ball, Liisa Viikari, and M. Enriqueta Arias. "Biomechanical pulping of spruce wood chips with Streptomyces cyaneus CECT 3335 and handsheet characterization." Holzforschung 59, no. 2 (February 1, 2005): 173–77. http://dx.doi.org/10.1515/hf.2005.027.
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AbstractThe actinobacteriumStreptomyces cyaneusCECT 3335 was evaluated for its ability to delignify spruce wood chips (Picea abies) after 2 weeks of incubation prior to refiner mechanical pulping. Weight loss of the chips during the treatment ranged from 2% to 3%. Chemicalanalysis of the treated wood showed an increase in acid-soluble lignin content concomitant with a notable increase in the acid/aldehyde+ketone [AC/(AL+KE)] ratio of the lignin compared with the control. Structural alterations in wood cell walls were observed by optical and scanning microscopy using astra blue-safranin staining and cryosections stained with gold/palladium, respectively. A gradual loss of lignin from the lumen towards the middle lamella and incipient defiberization could be observed. The estimation of specific energy for the defibration and refining stages of treated pulp showed a 24% reduction in the energy required, largely due to a 30% saving in the defibration of chips. The analysis of handsheets obtained from treated pulp showed a notable improvement in some strength properties, such as breaking length, tear index and stretch. In addition, the high Gurley air resistance value indicates more packing of the voids of the fiber network. These results demonstrate for the first time the suitability ofStreptomyces cyaneusfor biomechanical pulping purposes.
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Tanase, Mihaela, Per Stenius, Lars Johansson, Jan Hill, and Christer Sandberg. "Mass balance of lipophilic extractives around impressafiner in mill and pilot scale." Nordic Pulp & Paper Research Journal 25, no. 2 (May 1, 2010): 162–69. http://dx.doi.org/10.3183/npprj-2010-25-02-p162-169.
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Abstract Removal of extractives from the pulp furnish is of great importance for the improvement of paper machine efficiency and also for reducing the energy consumption during the thermomechanical pulp refining process. Extractives can exist in many different forms in the process water; as colloidal particles, dissolved or attached to fines and fibres. It is therefore important to know in which form they exist in order to fully understand their behaviour. In this paper, we report on an evaluation of the removal of extractives released from chips of different raw materials pre-treated in an Impressafiner, in pilot and in mill scale. In pilot trial the raw materials used were loblolly pine and white spruce and in the mil scale trial the raw material used was norway spruce. The colloidal stability of extractives present in the pressate water from the Impressafiner and their flocculation behaviour by cationic polymers (CPAM and Poly-DADMAC) under different conditions was also investigated. Calculations of mass balances around an Impressafiner showed that it was possible to remove up to 40% of extractives before the refining process. The reduction in total extractives content was mainly due to released resin acids while fatty acids, triglycerides, steryl esters and sterols to a large extent remained in the wood chips after pre-treatment. The removal of extractives from pine was four times higher than from spruce chips. The results can be explained in terms of the extractive composition in the raw material and the morphological differences in the wood structure.
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Hafrén, Jonas, Erik Nelsson, Hans C. Gerritsen, and Arjen N. Bader. "Optical properties of thermomechanical pulp (TMP) obtained from sulfite-pretreated Norway spruce with focus on two-photon spectral imaging (TPSI)." Holzforschung 66, no. 7 (October 1, 2012): 817–24. http://dx.doi.org/10.1515/hf-2011-0184.
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Abstract Chips of Norway spruce have been impregnated with Na2SO3 and refined at two specific energy consumptions levels at full mill scale. The optical properties of thermomechanical pulps (TMPs) obtained were analyzed in terms of brightness, light scattering, opacity, and autofluorescence by spectral imaging. Even at low sulfite dosage (0.24% sulfite by dry weight) light absorption was reduced, and the brightness was elevated, and a clear dose-response effect was observed. Two-photon spectral imaging (TPSI) showed that sulfonation, impregnation, and refining affect the fluorescence properties differently. Compared to native wood, both processed wood chips and pulp fibers revealed blue-shifted fluorescence maxima, a characteristic of shortened conjugated systems. Two subpopulations of fibers with different optical properties were observed, and the fluorescence of one fiber population was red shifted.
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Fraas, Art, and Alex Egorenkov. "Retrospective Analyses Are Hard: A Cautionary Tale from EPA’s Air Toxics Regulations." Journal of Benefit-Cost Analysis 9, no. 2 (August 17, 2017): 247–84. http://dx.doi.org/10.1017/bca.2017.8.
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Under the 1990 Clean Air Act Amendments, the U.S. Environmental Protection Agency (EPA) was required to establish standards limiting air toxics emissions from industrial plants. This paper examines the effects of five of the largest-cost rules issued by EPA in the initial round of air toxics rulemaking over the 1995 to 2000 period. Our estimates suggest that plants in the printing and publishing and pulp and paper industries realized important reductions in their air toxics emissions in the period between publication of the final rule and the effective date for compliance with the rule – although the reduction in air toxics emissions by pulp and paper mills fell short of EPA’s ex ante projections. However, our estimates also suggest that plants in three other industries – petroleum refining, pharmaceuticals, and wood furniture – achieved little or no additional reduction in air toxics emissions over the compliance period in response to EPA’s rules. Finally, the paper explores steps that EPA should take in setting up future retrospective analyses.
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Song, Xueping, Xiheng Kang, Yan Jiang, Min Wu, Shuangfei Wang, and Hui He. "Effects of Hot Water Pre-Extraction on Energy Consumption and Brightness of Bamboo Alkaline Peroxide Mechanical Pulp." Journal of Biobased Materials and Bioenergy 14, no. 3 (June 1, 2020): 349–58. http://dx.doi.org/10.1166/jbmb.2020.1961.
Full textAbstract:
The main purpose of this paper was to investigate the effects of hot water pre-extraction (HWP) on the refining energy consumption and the brightness of bamboo alkaline peroxide mechanical pulp (APMP). It was found that compared with un-extraction, the refining energy consumption dropped by about one-third after HWP. The reduction of energy consumption was proved through enhancing the channel of water and chemicals into inferior fiber based on the surface characterization of bamboo. Scanning electron microscope (SEM) images showed that the HWP made the fibers' structure loose and porous. Both pore volume and specific surface area were increased significantly after HWP, by 260.00% and 1804.76%, respectively. A decrease in pulp brightness was mainly due to the formation of new chromophore groups during the HWP process. The results of 13C nuclear magnetic resonance spectroscopy (13C-NMR) illustrated that some structures of milled wood lignin (MWL), such as guaiacyl, etherificated guaiacyl, and aromatic units, were increased during the HWP process. However, some lignin-links units of α-O-4, β-O-4, and some carbohydrate structures such as xylan, α- and β-glucose, and β-and β-mannose in lignin-carbohydrate complex (LCC) were evidently degraded. Additionally, most of the lignin and LCC were degraded under the simulative conditions of HWP bamboo. Furthermore, the analysis of UV spectrophotometry indicated that HWP was conductive to the generation of chromophore groups such as conjugated carbonyl, catechol, and o-benzoquinone.
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Bosco, Mtweve, Ekael Mbise, and Rwaichi Minja. "Production of Paper Pulp Using Sisal Fiber Waste from Sisal Spinning Processes." Tanzania Journal of Engineering and Technology 41, no. 2 (June 30, 2022): 150–57. http://dx.doi.org/10.52339/tjet.v41i2.788.
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Disposal of large volumes of textile waste is an escalating problem for textile industries. Sisal spinning industry is the one of the textile industries releasing large volumes of textile waste in the landfills. The rising costs, and reduction of available space together with increasing stringent environmental measures are making burying and land filling of textile waste, a declining option. This study therefore explores recycling options where the potential of using sisal fiber waste produced during sisal spinning processes as raw materials for the production of paper pulp was investigated. Sampling was done at 21stCentury Holdings Limited allocated at Chang’ombe industrial street Dar es Salaam mainly dealer of sisal yarns production. Materials were prepared and cut into small pieces of about ½ inches to reduce the fiber into unit lengths so as to achieve pulping required performance. Pulping process was achieved through Soda pulping techniques with two different effective alkali charges (EA-20% and EA-24%) for 240 minutes under maximum temperature 140 C, and liquor to fiber ratio 4:1by using Mathis Labomat dyeing Machine. The kappa number obtained was (25.5, 34.5) for material treated under EA 24% and EA 20% respectively, Percentage pulp yield were (47.1, 54.4) for EA 24% and EA20% pulp respectively. Freeness (630CFS, 555CSF) after refining at 4500rpm. Finally, the resulting pulp was used for hand sheet making and the sheets were tested for their mechanical properties; Grammage (61.1, 61.1) g/m2, Tensile index (9.9, 22.3) Nm/g, Tear index (13.3, 17.4) Nm2/g, burst index (1.7, 3.7 and 1.6) k.pa.m2/g and Elongation at break (2.02, 2.22) % for EA24% pulp, EA20% pulp respectively. The findings shows that sisal fiber wastes have a promising potential for paper pulp production compared to other non-wood raw material.
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Bicho, Paul, Elmer Portillo, Bernard Yuen, Dongbo Yan, and Doug G. Pitt. "Effects of precommercial thinning on the forest value chain in northwestern New Brunswick: Part 5 – Kraft and Thermomechanical pulping and pulp quality." Forestry Chronicle 89, no. 04 (August 2013): 490–501. http://dx.doi.org/10.5558/tfc2013-090.
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Forty-eight years after application, three nominal precommercial thinning (PCT) spacings of 4 ft (1.2 m), 6 ft (1.8 m) and 8 ft (2.4 m) were compared to an unthinned control in six replicate, balsam fir (Abies balsamea [L.] Mill.)-dominated stands. Following the clearcut harvest of three of these replicates in 2008, chips produced from sawmilling trials (slab-wood) and from the top logs of the sampled trees (top-log) were kraft and thermomechanically (TMP) pulped. In general, top-log chips took longer to kraft pulp, had lower yields, and produced pulps with shorter, finer fibres than the corresponding slab-wood chips, across all PCT treatment levels. The main effects of PCT on pulping occurred with slab-wood chips and not top-log chips. While end-product quality in either kraft or TMP production was generally unaffected by wood from the range of thinnings tested, slight reductions in slab-wood chip density and H-factor suggest that kraft pulping productivity may be reduced by 1.8% with furnish from thinned stands. While these losses could be offset somewhat by lower chip consumption, the economic benefits for a kraft mill are marginal at best, and sharing of fiscal gains across the fibre value chain needs to be explored. Specific refining energy required in TMP production was, however, reduced by 4% with furnish from thinned stands. These results suggest that value-chain optimization is ultimately dependent on the segregation of fibre from different sources, including within-tree and among silvicultural treatments and sites.
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RAYBON, HEATH, LAURENCE SCHIMLECK, KIM LOVE, FINTO ANTONY, JOE SANDERS, RICHARD DANIELS, EDWARD ANDREWS, and ERIK SCHILLING. "Examination of the potential to reduce water application rates for hardwood pulp logs stored in wet decks." AUGUST 2016 15, no. 8 (September 1, 2016): 523–30. http://dx.doi.org/10.32964/tj15.8.523.
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Wet storage of logs under sprinklers is often used to maintain log quality and to provide consistent fiber supply to wood production facilities. Concerns about water use in the southeastern United States have increased interest in refining water application strategies in woodyards. By understanding how the moisture content of stored logs varies over time in response to varying rates of water application, an optimum moisture regime for stored logs could be identified. In this study, experimental trials with nominal water application (100 mm/day) and a 30% reduction in water application were established at two hardwood woodyards in Georgia (Offerman, with sweetgum and yellow poplar, and McBean, with red oak and sweetgum). Variations in log moisture were monitored using time domain reflectometry for 12 months at Offerman and 15 months at McBean. Significant differences between treatments were observed initially, likely resulting from pre-existing differences in the wood before the start of the experiment, but differences in log moisture soon disappeared. Pulping trials conducted using McBean woodyard logs stored for 9, 12, and 15 months found that treatment had no effect on pulp yield, indicating that a 30% reduction in the amount of water applied results in little change in log quality.
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Janardhnan, Sreekumar, and Mohini M. Sain. "Isolation of cellulose microfibrils - An enzymatic approach." BioResources 1, no. 2 (September 21, 2006): 176–88. http://dx.doi.org/10.15376/biores.1.2.176-188.
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Isolation methods and applications of cellulose microfibrils are expanding rapidly due to environmental benefits and specific strength properties, especially in bio-composite science. In this research, we have success-fully developed and explored a novel bio-pretreatment for wood fibre that can substantially improve the microfibril yield, in comparison to current techniques used to isolate cellulose microfibrils. Microfibrils currently are isolated in the laboratory through a combination of high shear refining and cryocrushing. A high energy requirement of these procedures is hampering momentum in the direction of microfibril isolation on a sufficiently large scale to suit potential applications. Any attempt to loosen up the microfibrils by either complete or partial destruction of the hydrogen bonds before the mechanical process would be a step forward in the quest for economical isolation of cellulose microfibrils. Bleached kraft pulp was treated with OS1, a fungus isolated from Dutch Elm trees infected with Dutch elm disease, under different treatment conditions. The percentage yield of cellulose microfibrils, based on their diameter, showed a significant shift towards a lower diameter range after the high shear refining, compared to the yield of cellulose microfibrils from untreated fibres. The overall yield of cellulose microfibrils from the treated fibres did not show any sizeable decrease.
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Liitiä, T., S. L. Maunu, and B. Hortling. "Solid State NMR Studies on Cellulose Crystallinity in Fines and Bulk Fibres Separated from Refined Kraft Pulp." Holzforschung 54, no. 6 (October 25, 2000): 618–24. http://dx.doi.org/10.1515/hf.2000.104.
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Summary Solid state NMR spectroscopy has been used in this work to investigate crystallinity of cellulose in spruce wood before and after kraft pulping and TCF bleaching. Effects of refining of the spruce kraft pulp in water and in weak alkali have been studied by determination of the crystallinity of isolated fines and corresponding bulk fibres in order to find out whether the crystallinity in the fibre surface material and inside the fibre wall differ from each other. Also the possible effect of enzymatic endo-1,4-β-galactanase treatment on the crystallinity of some refined pulps has been investigated. It was found that the Iα crystalline form of cellulose predominates over the Iβ form in native spruce and vice versa in all the pulps studied. In pulping part of the cellulose Iα is converted to the more stable Iβ form mainly by heat. Any measurable changes in the degree of crystallinity or in the relative proportions of different crystalline forms of cellulose could not be seen in pulps after refining, TCF-bleaching or galactanase treatment. However, the degree of crystallinity was found to be considerably lower in the fines compared to the corresponding bulk fibres. Therefore it is suggested that the cellulose crystallinity is lower or the size of crystallites smaller on the fibre surface than inside the fibre wall. Slightly higher contents of lignin and hemicelluloses, mainly xylan and mannan, were also found in the fines compared to the bulk fibres.
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Salmén, Lennart, Jasna S. Stevanic, and Anne-Mari Olsson. "Contribution of lignin to the strength properties in wood fibres studied by dynamic FTIR spectroscopy and dynamic mechanical analysis (DMA)." Holzforschung 70, no. 12 (December 1, 2016): 1155–63. http://dx.doi.org/10.1515/hf-2016-0050.
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Abstract A deeper insight into the molecular interactions in the highly intermixed structure of the wood cell wall, from the point of view of both basic and applied science, is necessary. In particular, the role of the different matrix materials within the cell wall needs to be better understood, especially concerning how lignin contributes to the mechanical properties. In the present paper, the mechanical properties of spruce wood have been studied on a molecular scale by means of dynamic Fourier transform infrared (FTIR) spectroscopy. To this purpose, native spruce wood was subjected to chemical changes by impregnation and a mild pre-cooking with white liquor with a composition usual for kraft pulping. For comparison, lignin-rich primary cell wall material was also isolated by means of thermomechanical pulp (TMP) refining. Dynamic FTIR spectroscopy revealed that lignin took part in the stress transfer in all investigated samples. This finding is in contrast to literature data. A strong indirect coupling between lignin and cellulose was seen in the primary cell wall (P) material. In case of native wood, the lignin signal was much weaker and also indicated an indirect coupling to cellulose. In the case of pre-cooked wood samples (submitted to mild pulping), the interactions were modified so that the molecular straining of lignin was stronger and more directly related to that of cellulose. In other words, in these samples, lignin played a more active role in the stress transfer as compared to native wood. These findings were supported by a narrower lignin-softening region as measured by dynamic mechanical analysis (DMA). The interpretation is plausible in terms of the superior stiffness seen for high-yield pulps of a similar yield as the studied pre-cooked wood samples.
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Schirp, Arne, and Claudia Schirp. "Online Pre-Treatment of Thermomechanical Pulp with Emulsified Maleated Polypropylene for Processing of Extruded Thermoplastic Composites." Fibers 9, no. 3 (March 3, 2021): 17. http://dx.doi.org/10.3390/fib9030017.
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The effectiveness of maleated polypropylene (MAPP) in emulsified form for the pre-treatment of thermo-mechanical pulp (TMP) before extrusion with polypropylene fibres was evaluated. MAPP in pellet form, which was applied during the compounding step, served as a benchmark. In addition, commercial softwood flour was included as a reference. The influence of the temperature during the defibration process and the presence or absence of the coupling agent on composite performance were evaluated. Composites were processed with a high wood content of 70 wt.%, which is common for extruded profiles. It was found that TMP based on Robinia (Robinia pseudoacacia L.) conferred higher strength properties to the composites compared to TMP based on Scots pine (Pinus sylvestris L.), which was attributed to the higher length/diameter ratio of fibres in Robinia. However, under the conditions of this study, strength properties were superior and water uptake and swelling were reduced when wood flour was used instead of TMP. On the other hand, in many formulations, larger improvements in flexural and tensile strength due to MAPP were found for the TMP-based composites compared to the wood flour-based composites. This could be due to the larger surface/volume ratio for TMP compared to wood flour and more efficient stress transfer from fibres to the matrix. Results from X-ray photoelectron spectroscopy (XPS) showed that TMP surfaces were more hydrophobic than wood flour due to coverage with lignin, which reduced the effectiveness of MAPP. Esterification between the emulsified MAPP and fibre surfaces was determined using Fourier-Transform Infrared (FTIR) spectroscopy, but some non-activated maleic anhydride remained. Under the conditions of this study, MAPP added during compounding provided better performance compared to MAPP which included a non-ionic emulsifier and which was added during the refining process. Lower temperature (150 °C) during defibration was shown to be beneficial for the strength properties of composites compared to high temperature (180 °C) when MAPP was included in the formulations.
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Ibarra, David, Raquel Martín-Sampedro, Bernd Wicklein, Úrsula Fillat, and María E. Eugenio. "Production of Microfibrillated Cellulose from Fast-Growing Poplar and Olive Tree Pruning by Physical Pretreatment." Applied Sciences 11, no. 14 (July 13, 2021): 6445. http://dx.doi.org/10.3390/app11146445.
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Motivated by the negative impact of fossil fuel consumption on the environment, the need arises to produce materials and energy from renewable sources. Cellulose, the main biopolymer on Earth, plays a key role in this context, serving as a platform for the development of biofuels, chemicals and novel materials. Among the latter, micro- and nanocellulose have been receiving increasing attention in the last few years. Their many attractive properties, i.e., thermal stability, high mechanical resistance, barrier properties, lightweight, optical transparency and ease of chemical modification, allow their use in a wide range of applications, such as paper or polymer reinforcement, packaging, construction, membranes, bioplastics, bioengineering, optics and electronics. In view of the increasing demand for traditional wood pulp (e.g., obtained from eucalypt, birch, pine, spruce) for micro/nanocellulose production, dedicated crops and agricultural residues can be interesting as raw materials for this purpose. This work aims at achieving microfibrillated cellulose production from fast-growing poplar and olive tree pruning using physical pretreatment (PFI refining) before the microfibrillation stage. Both raw materials yielded microfibrillated cellulose with similar properties to that obtained from a commercial industrial eucalypt pulp, producing films with high mechanical properties and low wettability. According to these properties, different applications for cellulose microfibers suspensions and films are discussed.
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Pöhler, Tiina, Jukka A. Ketoja, Timo Lappalainen, Veli-Matti Luukkainen, Ilkka Nurminen, Panu Lahtinen, and Katariina Torvinen. "On the strength improvement of lightweight fibre networks by polymers, fibrils and fines." Cellulose 27, no. 12 (May 28, 2020): 6961–76. http://dx.doi.org/10.1007/s10570-020-03263-x.
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Abstract Novel lightweight cellulose fibre materials containing various strength enhancing polymeric and fibrillar components were formed with the help of foam technology. Increasing inter-fibre bond strength and local material density was attempted with unique lignin-containing wood fines (V-fines), cellulose microfibrils (CMF), TEMPO-oxidized cellulose nanofibrils (TCNF), and macromolecules such as cationic starch, polyvinyl alcohol (PVA), and locust bean gum (LBG). The investigated fibres included both long hemp bast fibres and northern bleached softwood Kraft pulp. In the low-density range of 38–52 kg/m3, the compression stress and modulus were highly sensitive to inter-fibre bond properties, the multi-scale features of the fibre network, and the foaming agent employed. Still, the compression-stress behaviour in most cases approached the same theoretical curve, derived earlier by using a mean-field theory to describe the deformation behaviour. At 10% addition level of fine components, the specific compression stress and compression modulus increased in the order of V-fines < CMF < TCNF. A tremendous increase in the compression modulus was obtained with LBG, leading to a material surface that was very hard. In general, the foams made with PVA, which acts both as foaming agent and reinforcing macromolecule, led to better strength than what was obtained with a typical anionic sodium dodecyl sulphate surfactant. Strength could be also improved by refining the softwood pulp. Graphic abstract
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Yakubova, Olga S., Elena Yu Demiantseva, Regina A. Smit, and Vladimir K. Dubovy. "Analysis of Micelle Formation and Adsorption Layers of Binary Mixtures of Sulphate Soap Components." Lesnoy Zhurnal (Forestry Journal), no. 6 (December 1, 2021): 196–205. http://dx.doi.org/10.37482/0536-1036-2021-6-196-205.
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Currently, the main trend of the pulp and paper industry development is bio-refining. It is based on integrated and deep processing of wood raw materials to obtain products with higher value added and reduced amount of waste. One of the high priority tasks of bio-refining is improvement of technology of by-product (sulphate soap) extraction from spent liquor with an increase in the yield and quality of the resulting product and a decrease in the level of environmental pollution. The complexity and energy intensity of sulphate soap extraction from spent liquor depends on many factors, including the species used for wood cooking, composition of extractives, the method of wood preparation for delignification, etc. Sulphate soap is a multicomponent emulsion with a predominant content of resin and fatty acids, small amount of unsaponifiable substances and an admixture of lignin, which is mainly extracted from waste liquior by settling. The low degree of its extraction is associated with the absence of systematical data on the mutual influence of the sulphate soap components. In this work, the patterns of intermolecular interaction of the individual components of the by-product (sulphate soap) are found. For this purposes the critical concentration of micelle formation (CCM) and surface tension depression of surface-active sodium oleate and sodium abietate and their mixtures of varying compositions were determined by the methods of tensiometry and conductometry. A detailed analysis of its mixed micelles and adsorption layers was carried out using the Rubin–Rosen pseudophase model. The interaction mechanisms of components in mixtures are explained. The impact on the composition of micelles and adsorption layers of the more surface-active sodium oleate was detected in mixed solutions. A maximum synergistic effect of micelle formation was observed in mixtures with a predominant content of sodium abietate. Analysis of experimental data and the result of sulphate soap modeling allow substantiating the complexity of its extraction from waste liquor after wood cooking with the presence of hardwood over 30 %, which is explained by the reduced content of resin acids in black liquor. For citation: Yakubova O.S., Demiantseva E.Yu., Smit R.A., Dubovy V.K. Analysis of Micelle Formation and Adsorption Layers of Binary Mixtures of Sulphate Soap Components. Lesnoy Zhurnal [Russian Forestry Journal], 2021, no. 6, pp. 196–205. DOI: 10.37482/0536-1036-2021-6-196-205
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Siadat, A., A. Bankes, P. M. Wild, J. Senger, and D. Ouellet. "Development of a piezoelectric force sensor for a chip refiner." Proceedings of the Institution of Mechanical Engineers, Part E: Journal of Process Mechanical Engineering 217, no. 2 (May 1, 2003): 133–40. http://dx.doi.org/10.1243/095440803766612793.
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Chip refiners are used to separate individual fibres from the wood matrix through the application of cyclic compressive and shear forces. The work presented here deals with the development of a two-axis piezoelectric force sensor to measure these cyclic forces in directions normal and tangential to the motion of refiner bars. The sensor consists of a small probe tip that replaces a portion of a refiner bar and is supported on four piezoelectric elements inside a housing. Stresses applied to pulp and wood material, at the surface of the probe, are thus transmitted to the piezoelectric elements, which respond by producing voltage signals. Signals from two of the four piezoelectric elements are used to determine forces in the normal and tangential directions during refining. A prototype sensor was tested in an atmospheric-discharge laboratory refiner. Impacts from individual bar crossings could clearly be discerned even at the maximum operating speed of the refiner. At low refiner speed, detailed measurements of the magnitude of the normal and tangential forces throughout a bar crossing were obtained. However, resonant vibrations of the sensor made it difficult to obtain such information when running the refiner at maximum speed. A number of design modifications are discussed, with the aim of improving the sensor performance for applications in larger-scale commercial refiners.
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Pydimalla, Madhuri, and Ramesh Babu Adusumalli. "Unbleached and bleached handsheet characteristics of Subabul heartwood and sapwood." Nordic Pulp & Paper Research Journal 35, no. 2 (June 25, 2020): 161–71. http://dx.doi.org/10.1515/npprj-2019-0055.
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AbstractThe objective of this study was to understand the influence of bleaching on % residual lignin, water retention value, brightness and morphological properties of Subabul heartwood and sapwood pulps. The second aim was to compare the properties of unbleached and bleached handsheets with respect to tensile index and fractography. Screened wood chips of Subabul were subjected to kraft cooking (165 °C, 3 hours) followed by ECF bleaching and refining. When unbleached handsheets were compared, higher tensile index was found for sapwood sheets (29.8 N.m/g) than heartwood sheets (12.8 N.m/g). Therefore, it is recommended to use unbleached sapwood sheets for packaging grade applications. The bleached pulps have exhibited negligible residual lignin (0.1 %), higher water retention value (∼21) and higher brightness (88 %) compared to unbleached pulps. Subsequently, the bleached heartwood sheets revealed higher tensile index (∼7 fold) and higher modulus of elasticity (∼2.7 fold) compared to unbleached heartwood sheets. For printing grade applications bleached sapwood and bleached heartwood pulps are equally recommended, because no differences were observed in their pulp and sheet characteristics.
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Ahmed, Syed Muzamil, S. N. Kazi, Ghulamullah Khan, Rad Sadri, Mahidzal Dahari, M. N. M. Zubir, M. Sayuti, Pervaiz Ahmad, and Rushdan Ibrahim. "Effect of various refining processes for Kenaf Bast non-wood pulp fibers suspensions on heat transfer coefficient in circular pipe heat exchanger." Heat and Mass Transfer 54, no. 3 (October 17, 2017): 875–82. http://dx.doi.org/10.1007/s00231-017-2176-3.
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