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JAPAN TAPPI JOURNAL November 2008


Vol.62 No.11 Abstracts


Basic and Application of Wet End Chemistry

Atsushi Watanabe
Pulp and Paper Research Laboratory, Oji paper Co., Ltd.

  The purpose of adding wet end chemicals and wet end chemistry practices are to achieve optimum paper properties and enhance papermaking efficiency. In recent years, papermaking condition has changed by use of variety of recycled paper, high amount of coated broke usage, increase in speed of paper machine and closed water system in paper mill. These trends complicate wet end conditions and make resolution of wet end problems difficult.
   In this paper, at first, basic wet end chemicals are introduced, and show some examples of analysis of deposition in paper machine and a useful way for selecting chemicals to fix problems.


The Approach to WET- END Process Optimization
-The Analysis Method for WET- END Process and Case Study-

Roland Berger
BTG Instruments GmbH

  Gaining greater productivity and paper quality is a systematic and continuous process. This statement is especially true for the Wet End of the paper machine. Many strategic additives are introduced to influence machine runnability and paper quality. At the same time there are only few areas of the paper machine with less automatic control. This paper will present two case studies of waste paper-based newsprint machines at the Papierfabrik Palm, Eltmann mill that led to better control in the Wet End.


The Application of Fuzzicide in White Water Circuit for Productivity Improvement

Hiroyuki Suzuki, Satoshi Kashiwagi, Sousuke Iwata, Hiroki Katsura, Katsuhiko Hidaka and Takumi Sugi
Technical Section, Pulp & Paper Industry Department, Kurita Water Industries Ltd.

  The trend in papermaking is use more recycled fiber in the furnish, maintain the pH of paper machine at neutral, reduce fresh water consumption. These changes accelerate the CaCO3 scale problems, the pitch problems and the slime problems.
   Fuzzicide is new inorganic slime control agent and can keep all papermaking processes clean. New monitoring tool can understand cleanness in the processes.
   These new techniques are able not only to decrease the spot and the sheet break but also to extend the operation period.


Optimization of the Passing Velocity for Primary Screens on PM5

Kotaro Soda
Yufutsu Mill, Nippon Paper Industries Co., Ltd.

  The start of No.5 paper machine (PM5) at Yufutsu Mill was in 1979. Currently, its capacity is approximately 300 metric tons per day. Its product mix includes wood free paper and base paper for thermal paper and no carbon copy paper.
   Originally, wet end was run at an acid pH. However, the machine has been converted to neutral pH with the use of calcium carbonate. The calcium carbonate was originally supplied by purchasing from another company. Then, as a cost savings measure, the calcium carbonate was purchased from another Nippon Paper mill.
   When this change occurred, there were increased incidents of screen baskets plugged with "stock lumps". There would defect randomly and cause sheet defects or sheet breaks.
   This report shows the results of passing velocity optimization of the primary screens to reduce stock lump build up and plugged screen baskets.


Improvement of Cleaning Procedure and Deposit Prevention in Stock Preparation

Takahiro Aya
Nichinan Mill, Oji Paper Co., Ltd.

  #2PM in Nichinan mill of Oji Paper was established in 1956 and has been modified in the part of stock preparation process in order to be satisfied with quality of the paper. Now we are making some base papers for Ink Jet printing paper, thermal paper used as specialty, ticket, sketchbook, specialty paper used as business card, and thick fine paper. These papers are used for digital imaging print and require low dart number because end users use them by a piece of sheet and look the fresh printed paper carefully.
   This is a report in regard to some improvements of the process and the operation for stock preparation.


Improvement of the Runnability for Paper Making by "Axisz System"

Koichi Tadaki
Technical Dept., Somar Corporation

  Neutral papermaking and high recycle fiber usage in recent years make papermaking more troublesome. Conversion of acid to neutral papermaking reduced popular use of alum. Increased recycled fiber usage promoted by global resource protection and environmental concern brings more foreign materials such as pitch and anionic trash in papermaking system. At Somar we have been working on wet-end improvement agent "Realizer A series" as functional coagulant which maximizes the effect of variety of wet-end chemicals. Latest polymer technology help us to develop another functional retention aids as "Realizer R series" and "Rexer FX series" which are effective in fine and ash retention. Synergistic effect of the combination of these chemicals to improve wet-end performance is referred as "Axisz System".
   It developed by Somar will give a solution to the problems associated with wet-end operation. The new chemical assists retention of other wet-end chemicals, thus reducing total chemical usage. It also improves drainage and fiber retention. Optimization of wet-end operation using "Axisz System" can be achieved by proper selection of cationic charge, molecular weight and molecular weight distribution. It depends on stock characteristics and other chemical usage. Maximization of the effect with "Axisz System " is demonstrated.


Operating Experience of "Intensa Pulper", The Newly Developed Low Consistency Pulper

Akihiro Yamamori
Oita Mill, Oji Paperboard Co., Ltd.

  Oji Paperboard Co., Oita Mill has three paper machines, No.1, 3 and 5, and produces gypsum board, white and colored board, core paperboard, etc. other than main product of linerboard.
   As the blending rate of the old corrugated containers (OCC) into the paper products now reaches around 80 percent here, the energy saving in the OCC pulping process and the quality improvement of the recycled pulp have become very essential and important to realize more effective secondary fiber system.
   For this purpose the first "Intensa Pulper" in Japan, which was developed by Voith IHI Paper Technology Co. was installed in the OCC pulping process with result of the extensive power saving and the significant improvement of the OCC defibering characteristics.
   In this paper, what and how the Intensa Pulper is and its operation experience and running effect are reported.


A New Design for Paper Dry Strength Agent and Its Application Method in Wet End

Hiroshi Nakagawa
Paper Chemicals Division, Arakawa Chemical Industries, Ltd.

  Encouraging environmental protection and conservation program, an amount of recycled paper and paper board furnish has been increasing in Japanese. On the other hand, it has become very tight to get used paper in the domestic market recently. A large volume of used paper has been exporting towards China with better price, therefore Japanese paper industry must use lower grades furnish. Such fibre materials cause papermaking conditions worse and hard to control machine runnability.
   Many companies have introduced new machines in East Asia, and production cost is very important for domestic papermakers to survive in the market. However, the price of used paper has been increasing dramatically, and optimizing lower quality grade fibre has to be inevitable. In order to produce paper and paperboard by a high speed machine using such grade fibre, high performance wet-end chemicals must be developed to achieve better machine control and cost reduction.
   In this paper, recent technical trends of polyacrylamide (PAM) based dry-strength agent and partially cationic starch were discussed. In particular, treatment systems of blanched chain structure PAM combination was investigated, in which two or more type of each PAM equipped different coagulation force. This application could be useful for various papermaking systems and it is expected to be applicable to more complicated wet-end condition and high speed machine papermaking.

kajaaniWEM & kajaaniRM3 - The Integrated Management from Stock to Wet-end

Jukka Nokelainen and Takeshi Sato
Process Automation Systems Division, Metso Automation

  This paper introduces two lately launched superior tools for wet end management: modular multi talent analyzer and consistency sensor. The consistency sensor is stand-alone device that performs continuous measurements from one sample point. It is ideal for applications that require continuous total and true ash consistency measurement and automatic control. The new analyser is first in the world that provides papermakers with all the right and relevant wet end measurements. Here we describe by several living examples of charge, pH, temperature, redox, conductivity, and consistency measurements, how to get comprehensive understanding over paper making from Stock to Wet-end and point out process problem areas and find right actions to correct them.


A Report on the 2008 Japan-China Pulp and Paper Technical Exchange Symposium

Takashi Ochi*1, Yutaka Kaneko*1 and Kunitaka Toyofuku*2
*1Nippon Paper Industries Co., Ltd.
*2JAPAN TAPPI

  The second Japan-China technical exchange, "2008 Japan-China Pulp and Paper Technical Exchange Symposium", sponsored and arranged by Japan TAPPI, China TAPI and Shandong Light Industry Institute, was held on May 20-21, 2008 in Jinan, Shandong, China. The number of participants of both countries was almost 200. Before and after the symposium, Japanese participants visited five paper mills.


A Report on the 21st ISO/TC6 Meeting

Takayuki Okayama*1, Toshiharu Enomae*2, Yasuhiro Oba*3, Kyoji Kishi*4, Shisei Goto*4 and Tadashi Kano*5
*1 Tokyo University of Agriculture and Technology
*2 The University of Tokyo
*3 Oji Paper Co., Ltd.
*4 Nippon Paper Industries Co., Ltd.
*5 Japan Technical Association of the Pulp and Paper Industry

  ISO/TC6 meeting was held on June 9-13, 2008 in Seoul, South Korea. The number of registered delegates representing seventeen countries was seventy three.
   Eight delegates representing Japan attended WG meetings, plenary meetings of SC2 and SC5, and TC6 plenary meeting.


Theoretical Study of the Sheet Transport Speed with the Rubber-Covered Roller

Takao Kobayashi and Shinji Nakayama
Pulp and Paper Research Laboratory, Oji Paper Co., Ltd.

  In this study, systematic consideration about the sheet transport speed was performed with the finite element analysis. Poissonfs effect does not appear in compressible materials such as urethane, and volumes just decrease by compression whereas the normal rubber shows the incompressibility which keeps a fixed volume. The sheet transport speed ratio (the ratio of the movement speed of the sheet for the peripheral speed of the rubber roller) is almost in proportion to a tension difference in front and back of the nip without depending on a value of the sheet tension. It has an increasing linear relationship with the contact pressure of the roller in the case of the incompressible rubber and has a decreasing linear relationship in the case of the compressible material. It was confirmed that this speed ratio depended on a tangential elastic strain of the rubber roller in the stick region by simulation.
   In the applied example assumed a printer paper feed tray, we understood that when the sheet was transported with a pickup roller, the frictional force from back side of the sheet had an influence on the speed ratio greatly. When a pickup roller was located in the one side, it followed that frictional force by the weight of the sheet became the resistance, and skew occurred. When two pickup rollers were arranged in parallel and the contact pressure of each roller was not equal, the transport speed difference caused skew. In this case, it is predicted that buckling occurs if skew will be controlled forcibly by side plates.

Keywords: finite element analysis, sheet transport speed ratio, incompressible rubber, compressible material, rubber-covered roller, elastic strain