2004年12月 紙パ技協誌

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JAPAN TAPPI JOURNALVol. 58, No.12

December 2004    Abstracts


Solutions for a Bright Future in Papermaking

Heikki Ilvespaa

Metso Paper, Inc.

 In many old line industries investments have slowed down due to slow payoffs. This trend is turning much of traditional manufacturing into a technological backwater. In a world where productivity and related investments are key, sluggish productivity improvements result in a vicious cycle with little prospects for big returns. Only proactive productivity development, product quality improvements or new business approaches will lead to long-term success in the paper industry.
 In addition to the productivity challenge there is the anticipated threat of electronic media. But the worldwide per capita consumption of paper is still increasing. It is predicted that worldwide paper consumption will continue to grow at 2%-4% annually.
 The growing consumption of paper is driven by a thirst for knowledge, and so long as the cost of paper is competitive relative to competing media, its versatility in terms of accessibility will secure it a strong market position long into the future.


Retrofittin Consistency Profiling Systems to Existing Headboxes
  -Results from the First BTF Dilution Control System in Japan-

Junichi Yano

Mechanical Designer Paper Machinery, Kawanoe Zoki Co., Ltd.

  In July 2003, a BTF Central Distributor, with automatic dilution control, was installed on the existing Escher Wyss headbox on paper machine No 3 at Marusumi Paper Co., Ltd. Kawanoe mill.
  The goal of this project was to improve the CD basis weight profile, to reduce the grade change time and to improve the sheet edge quality for producing wider sheet.
  All grades produced so far are running around 50% or better than the 2-sigmas that were previously (before BTF installation) achievable. The grade changes are much faster and are now done within five minutes. The basis weight profile is no longer an issue during grade changes.
  And the sheet edge quality was improved so that 30mm wider sheet can be produced.


The Latest Headboxes for Board and Packaging Grades

Motoaki Sato

Voith IHI Paper Technology Co., Ltd.

 The one of the most important parameter for product quality in board and packaging (B&P) grade is still its strength basically. But new trend in B&P grade is reduction of basis weight, and requirement in product is not only its strength but also the fineness of the surface quality, which influence printability. Due to these tendencies, better quality and higher performance must be required for the headboxes for B&P grade compared with those in the past. VOITH Paper had developed MasterJet headboxes, based on the well-known technology of the high-turbulence W-type headbox and ModuleJet dilution control, to meet the higher demands from the paper industry. On the other hand, VOITH Paper also considers economical solutions for the B&P grades.


SUCCESS FORMER and Its Application in Overseas

Masahito Mukai and Takashi Suzuki

Paper Machinery Engineering Dept., Kobayashi Engineering Works, Ltd.

 The Pulp/Paper Industry is growing more intense in competition globally. Under the Present circumstances, “Success Former” is the very effective machine to achieve the Purpose of improving both productivity and quality of paperboard. In this thesis, we would like to introduce the structure and characteristic of it, also explain how it has been developed in such a high growth market like China.
  “Success Former” is designed based on Kobayashi’s original ideas, to realize excellent formation and superior quality for Multi-layer paperboard. We have many achievements for producing various kinds of paperboard in domestic and abroad markets. The most remarkable point is “Success Former” has obtained a high evaluation in China of late. We have exported 2 complete units to China in recent 3 years. Both of them had smooth start-up, which truly satisfied our customers with the high advantage to their investment. Here, we will introduce an example.


Theory and Practice for Formation

Hidehiko Yamazaki

Metso-SHI Co., Ltd.

Michael Odell and Pekka Pakarinen

Mestp Paper, Inc., Jyvaskyla , Finland

 This paper is an overview of the theory and practice of improving formation. The aim is to provide background information for mill personnel to understand the basic mechanism of formation improvement and how these mechanisms can be controlled in practice. The scope of the paper is mostly related to paper grades and concerns all headbox and forming section types. There is a lot of relevance in this discussion also for board grades although the emphasis is primarily on paper.
 The principles of how formation is influenced by fibre concentration, shear, turbulence, flow elongation and drainage are explained. In the furnish and stock preparation area the influences of fibre properties, refining, wet end chemistry and formation improving additives are discussed. There is a section on formation measurement intended to brief the reader on what measuring methods are appropriate for different uses and how new measuring methods can characterize the appearance of formation. Formation improvement cannot be considered in isolation from other paper properties so while formation is the main theme of this paper the consequences of formation tuning activities on other paper properties are also described.
 The emphasis on practical tuning in this paper is on how to optimize the headbox and former operation. There are sections in this paper concerned with formation fault finding, systematic tuning procedures and strategies for routine formation control. A new formation tuning technique based on measurement and control of Z direction formation profile is introduced in this paper.


Latest Technology of Forming Section
  - Bel Baie Former Upgrade with VentaShoe Technology -

Keiichi Fujiki

Mitsubishi Heavy Industries, Ltd. Paper & Printing Machinery Division

  Mitsubishi Heavy Industries, LTD. has developed a new technology that combines the best aspects of roll-blade and pure blade forming. This new technology consists of replacing the initial forming zone with a grooved smaller radius blade design. Rework to a former and headbox is minimal.
  As in roll forming, the VentaShoeTM traps the jet more symmetrically with a positive angle to the wires that reduces the jet impingement sensitivity. Reduction in jet impingement sensitivity provides easy operation without any defects such as spotting. The blade drainage section provides the superior formation of a traditional blade former.
  There are currently eleven papermachines utilizing this new technology in the field. The first started up in North America in 2001. All have been demonstrating many benefits in terms of paper qualities and papermachine operation.


Shoe Press Technology for the Dewatering of All Paper Grades

Takeshi Nonogaki

Voith IHI Paper Technology Co., Ltd.

  The important technological and economic advantages have expanded the use of shoe press technology to dewatering of all paper products from pulp and tissue. Whereas the development of NipcoFlex technology began in packaging paper machines 20 years ago, this technology can today be found in virtually all applications for the mechanical dewatering of the paper web in new and modernized production systems. The portfolio offers an economic solution for increasing productivity and efficiency for any requirement, whether a rebuild or a new machine. The advantages of shoe press technology are now also utilized in calendaring in the paper industry.


Remodeling Shoe Press of PM10

Kenji Kurimoto

Kasugai Mill, Oji Paper Co., Ltd.

  The PM10 at Kasugai Mill, Oji Paper, was started up in February 1991, and it has been produced wood-free paper and coated paper. Chiefly, remodeling shoe press installed in the third nip was achieved continuous stability operation with design speed 1,300m/min in January 2002. In the past, there were problems of drier dryness ability shortage and production rate restriction due to insufficient pressed. The shoe press has brought a 4% to 8% increase in dryness compared to roll press. After remodeling, shoe press has been evaluated at high contribution degree to improve both paper quality and productivity and have been considered to be indispensable equipment for quality improvement and increased machine speed, and the production increase plan was achieved.
  In this report, it reports around the outline of remodeling, the operation experience, and the effect of the introduction.


Quality Improvement by Remodeling the Headbox and the On-top Former in PM7

Tomoki Kitamura

Niigata Mill, Hokuetsu Paper Co., Ltd.
 
 Niigata mill PM7, which started up in 1990, produces A2/A3 coated paper with on-line coating. PM7 had quality subjects that had to get over and the reached conclusion was that the improvement of the base paper profile and formation were indispensable. Therefore, the remodeling of the headbox and the on-top former were carried out in 2001. The “SymFlo-D” was adopted for the headbox that controls the BD profile by dilution. The wire section renewed to “Duo-D former” that achieves the remarkable formation improvement effect applying by the counter blades. This report shows the overview of the equipment, the operation and the quality improvement by the remodeling.


Improvement of Hardwood Pulp Yield in Continuous Kraft
Cooking and Estimation of Pulp Yields (Part III)
  -Pulp Yields of Isothermal Cooking with Kraft and Polysulfide Liquors as well as Anthraquinone-

Tomoya Yokoyama and Hiroshi Ohi

Graduate School of Life and Environment Sciences, University of Tsukuba

  The pulp yield was improved by about 4.5-5% when polysulfide(PS) and anthraquinone (AQ) were added to the kraft cooking liquor (white liquor). The exchange of the black liquor with fresh white liquor further increased the yield. The highest pulp yield was obtained when the PS cooking liquor containing 70% of total active alkali (AA) and 100% of AQ was used from the beginning of the reaction and the black liquor was exchanged with fresh white liquor containing the residual 30% of AA just after temperature reached 135℃.
  There was a good correlation between kraft pulp yields of a hardwood species and the ratios of the amount of xylose to glucose (X/G ratio), liberated by an acid hydrolysis of the pulps. However, the correlation was dependent on raw material wood species. Therefore, it is required in advance to establish a correlation between the yields and X/G ratios for raw material wood species of a target pulp in order to estimate pulp yield using X/G ratio. The X/G ratios of relatively high yield pulps showed higher values than those expected from the correlation.
 In a mill trial, the superiority of the PS-AQ ITC process over the kraft ITC process was confirmed by examining X/G ratio of pulps obtained. The pulp yield in the PS-AQ ITC process was estimated at about 57.0%. This yield is very high, which indicates that reaction conditions of the PS-AQ ITC process are optimal.

Keywords: kraft isothermal cooking, polysulfide, anthraquinone, carbohydrate, pulp yield, mill trial