Vol.62 No.7 Abstracts

Advanced Control of the Pulping Process by Using New Online Fibre Analysers

Hakan Karlsson
Product Manager, AB Lorentzen Wettre (Sweden)
Yoshihiro Ohkawa
Managing Director, Lorentzen Wettre K. K. (Japan)

  Shape factor is maybe the most important measurement for kraft pulp. L&W STFI Fibermaster was developed to be able to measure this important property better than other instruments. Fiber length is measured according to ISO standard. A number of other properties are measured and available for on-line measurements as well as for laboratory analysis. Applications for modelling of pulp quality, optimisation and control of refining and blending of pulp are described. The latest development has been to analyse vessel cells and shives in more demanding situations including recycled pulps.

The Latest Sensor, Online Analyzer and Control Technology for Chemical Fiber Line

Naoto Takigawa
Sales Manager, Metso Automation K. K.

  The purpose of this paper is to review the best available measuring equipment and controls for ECF and TCF bleach lines. The target for a complete chemical pulp bleaching line is to bring the Kappa number down to zero and to reach the final brightness target. However, to control a bleaching line, we have to look at each stage separately and decide what the objective is, how we will monitor the success of the stage, what we will control, and how.

Status of Use and Tasks for Gaskets to Replace Asbestos Gaskets in Alkaline Line of Kraft Pulp Production

Yukihiro Nagao
Sealing Products Department, Nichias Co., Ltd.

  In Japan, the usage of sealing materials containing asbestos had been banned across the board as of the 1st of September, 2006 in the facilities and equipment in paper and pulp manufacturing industry.
  We are herewith to introduce the properties, problems, recommendations as well as the status of use for non-asbestos gaskets to be applicable to alkaline of kraft pulp production which has been said to be the hardest to replace the asbestos gaskets in paper and pulp manufacturing industry.

The Selection of Non-asbestos Sealing materials for Pulp & Paper Plants

Shinji Koike
Basic Technology Industries Development Division, Nippon Valqua Industries, Ltd.

  The harmfulness of Asbestos and the necessity for alternative material had been recognized, still in Japan the conversion has been delayed in comparison with Europe and the United States. However, even in Japan, the seriousness of health damage by Asbestos came to attract the attention and then the manufacture and sale of Asbestos products were banned in principal by law enforced in Sep. 2006.
  We as Gasket manufacturers have been carrying out research & development of alternative materials and there are already many products with which can replace asbestos in various applications on the market.
  In this report, I am going to talk about soft gaskets and gland packing for Pulp & Paper industries and explain the points of material selection in time of changing from Asbestos to Non-asbestos.

The AIKAWAfs Newest Refining Technology
-From the Standpoint of the Refiner & the Refining Fillings-

Kazumi Fujita
Technical & Engineering Department, AIKAWA IRON WORKS CO., LTD.

  Nowadays, we have two major issues in the Refining process.
  One is to reduce the power consumption from this most power consuming process in the stock preparation system.
Second is the suitable Refining method according to the changes of the resent stock fiber condition. Hard wood pulp, OCC and ONP are most commonly used as paper material. But recently, the ratio of plantation Hard wood pulp is rapidly increasing and the recycling rate of OCC and ONP are also increasing which both resulting to shorten the fiber length and becoming the lowering factor of fiber freeness.
  To use this short and weak fiber, not cutting Refining but wet beating with less fiber cutting and property (strength) improvement could be the solution. In general, better Refining efficiency means the larger freeness drop with less power consumption and not wet beating. But the resent need in refining is to achieve good balance between these two, power reduction and property improvement with wet beating.
  In this report, we would introduce our approach to these issues with our newest technology, Aikawa Double Conifiner (ADC) and Finebar Refining plates, and its merits.

Keywords: Refining energy saving, Planted hardwood pulp, Recycled OCC & ONP, Fiber length & freeness, Cutting refining, Wet beating, Refining power consumption, Fiber characteristics, Aikawa Double Conifiner (ADC), Finebar

Impact of the Design of LC Refiner

Yosuke Takeshita
Sales & Technical Group 2, Andritz K. K., Japan

  In Japan all kind of fiber material of paper furnish strength is becoming low. For keeping the paper quality, refining process is very important now. Andritz have long history of manufacturing the low consistency equipment and systems for paper machine stock preparation. This report explains the Andritz 3 types refiners laboratory results of fiber impact by design and Fractionation refining process for keeping the paper quality by ecological method.

Selection of Fixative against Pitch Troubles, etc.

Kensuke Shimizu
BASF Japan Ltd., BM Specialties, Paper Chemicals Technical Service

  Change of environment around paper manufacturing and technology leads improvement the paper-production efficiency. However, in the other hand, these cause change of type of detrimental substances and amount of detrimental substances in paper making system, and negatively impact to the paper-making. These negative impacts to paper making are roughly classified into (1) troubles on the process and instability of effects of wet-end chemicals and (2) problems on the paper qualities and dirt of the machines. Therefore, it is necessary to select suitable measures (charge control and fixation) and suitable coagulants (charge controller and fixative) depending on the types of troubles happened at paper-making. Each evaluation method of effects of coagulants has merits and demerits respectively, so it is difficult to evaluate the effect of coagulant with only one method.
  Therefore, it is necessary for selection of coagulant to apply suitable combinations from various evaluating methods depending on the purpose or problems should be solved. Laser pitch counting technology that was developed by BASF can evaluate the effect of coagulant as quantitatively by resulting pitch size distribution. Therefore, it is one of powerful tool for fixatives with the feature in a past evaluating method without. Further, it is also effective tool for the development of new coagulants.

Pitch Control with Pulp Quality Change

Satoshi Wada, Chen Jiayi and Keiji Suruga
Paper Chemicals Section, Kurita Water Industries Ltd.

  Recently, papermaking industry has executed waste paper recycling actively from the situation of global environment maintenance and resources protection. With this situation, pitch trouble has been increasing by increasing of the wastepaper usage rate, neutralization of papermaking pH, reduction of papermaking machine using water, speedup of papermaking machine. Pitch trouble is one of important cause of paper machine run ability.
  To reduce pitch trouble, various pitch control agent has been applying. And many pitch evaluation methods has been using. Each method has various features and is used depending on the situation and a purpose. We use evaluation method noting gDeposit potentialh, and we are applying pitch control agents and fixing agents.
  In this article, we collect concerning the basic item of the pitch and pitch control. And we introduce the example of application of the pitch control agent.

The Effects of Chemical and Mechanical Modifications of Pulp Fibers

Akira Isogai
Graduate School of Agricultural and Life Sciences, The University of Tokyo

@Chemical and mechanical modifications of pulp fibers based on the chemical structures of the pulp components and hierarchal tissue structures of pulp fibers are reviewed in this paper. In the mechanical modifications, the highly crystalline cellulose microfibrils and micropores formed in the cell walls during chemical pulping process play a significant role in controlling paper properties as well as retention of wet-end additives. On the other hand, carboxyl groups present in pulp fibers are key interaction sites with various cationic compounds in papermaking and coating processes. There have been various procedures reported so far to improve carboxyl contents in pulp fibers. Irreversible adsorption of carboxymethyl cellulose with low degrees of substitution on pulp fibers is a new and interesting chemical modification of cellulosic fibers, resulting in increases of carboxyl contents of the pulp fibers and in improvement of the effects of wet-end additives. TEMPO-mediated oxidation of pulp fibers is also a promising procedure to introduce carboxyl and aldehyde groups into pup fibers without any changes in crystallinity or fiber morphology. Especially, cellulose single nanofibers 3-4 nm in width and a few microns in length can be prepared from TEMPO-oxidized pulps by moderate disintegration in water.

Development of Continuous Cooking Process for Kraft Pulping

Yan Ju
Metso Paper Japan Co., Ltd., Fiber Business Line, Technical Support

  Since Kamyr has invented the continuous kraft cooking system in 1949, it was significantly developed along with the improvement of the cooking process in order to meet the different requirement in the past 30 years. A number of cooking processes such as MCC, ITC, and BLI were developed, and have been playing an important role in Japanese paper industry even today.
  Metso Paperfs fiber business line (former Kvearner Pulping) had fully inherited Kamyr technologies, and developed COMPACT COOKINGTM system that has become a most popular continuous kraft cooking process. COMPACT COOKINGTM system can fully meet the requirement to, (i) build a new fiber line both for hard wood and for soft wood, (ii) increase the capacity for the existing cooking system, (iii) modify the existing cooking system for the purposes of increasing cooking yield, bleaching ability, and pulp quality as well as for the purposes of reducing energy consumption and environmental load.
Keywords: Continuous Cooking Process, MCC, ITC, and BLI, COMPACT COOKINGTM

Analysis of Relationship between Air Bubble Size Distribution in Flotator Cell and Deinking Efficiency
-Progress in Development of a New OK-Flotator-

Atsushi Watanabe
Pulp & Paper Research Lab., Oji Paper Co., Ltd.

  With a view to improving the ink elimination in Flotator, We directed our attention to the bubble size distribution and examined the relationship between operating condition and deinking efficiency of the flotator. We found that higher rim speed of the rotary tube blower could increase deinking efficiency and the brightness gain drastically. At that time, higher rim speed caused smaller air bubble size.
  When the speed was high, large air volume improved deinking efficiency and the brightness gain, then would increase the number of small air bubbles.
  On the other hand, when the rim speed was low, large air volume was not effective in deinking, then would increase the number of large air bubbles.
  By applying these findings to OK-Flotator, and could succeed in improving the deinking efficiency.

Keywords: OK-Flotator, ink, bubble size distribution

Improvement of DIP by Optimization in Process Control

Yoshio Ito
Chuetsu Pulp and Paper Co., Ltd., Takaoka Mill (Nomachi)

  Collection of waste-paper and its recycling rate have been going up year after year in order to establish an ecological society here in Japan. The recent trend toward environmental preservation has spoiled a balance between demand and supply of waste paper. There is no other choice but to use a poor quality waste paper for recycling, according to the boost in domestic market price due to increasing exports for waste paper. Under these circumstances,@quality problems have been increasingly caused by dirt such as stickies and plastic films residual inks from the inferior waste paper during DIP process.
  Deinked pulp contains many types of paper products at Nomachi in Takaoka Mill, while strong demand for higher quality product is rising in the market.
  This report described our effort to reduce obstacles in DIP production process to satisfy the strict market demand.

The Technology of Deinked Pulp Made from Low-grade Recovered Paper

Tomoaki Koyanagi
Research Laboratory, R&D Div., Nippon Paper Industries Co., Ltd.
Takuya Yonemoto
Pulp Department, Yatsushiro Mill, Nippon Paper Industries Co., Ltd.

  It is apparent that promoting the utilization rate of recovered paper in paper manufacture is a key point to reach the target of 62% by 2010.@The paper manufactures have started to consume not only old newspapers but also old magazines and fine paper printed. On the other hand, the recovery rate reached 72.4% in 2006 while it was a strong growth of recovered paper export to China. The supply of high quality recovered fine paper has been restricted.
  Nippon paper industries has promoted the use of various grades of recovered fine paper for paper manufacture to produce the stable deinked pulp. We describe the latest technology of the high brightness deinked pulp production.

The Rebuild of DIP Lines at Kanto Mill (Katsuta)

Katsushi Mineshima
Kanto Mill (Katsuta), Hokuetsu Paper Mills, Ltd.

  DIP lines in Kanto Mill (Katsuta) have started its operation since 1975 with a paper machine. Since there is only one paper machine, the operation of DIP lines is matched with what kind of waste paper as raw material is needed for production of the paper machine and how much amount of waste paper should be required for it.
In the original plan, the DIP lines were designed for treatment of newsprint as main raw material, but we installed drum pulper and kneader and remodeled coarse-screen and bleaching process in order to enhance the volume of production, quality and brightness.
  Since then, the two DIP lines (one is BDP which has bleaching process, the other is DIP which is non-beaching process) are operated and producing DIP, treating newsprint, magazine, and woodfree-based waste paper.
This report shows the details of remodeling of the DIP lines and the result after remodeling after 2003.

Countermeasures against Dirt in Waste Paper Treatment Process

Tooru Shimomura
Hachinohe Mill, Mitsubishi Paper Mills Limited

  In Hachinohe mill, we produce deinked pulp with high brightness. The pulp is mainly made from coated book stock (CBS). However, the procurement of CBS has become difficult by the elevated price of waste paper. Therefore, we are forced to utilize several types of raw materials such as waste magazine.
  We have tackled the quality loss of the raw materials and stabilized the pulp quality by performing several countermeasures: preventing stickies from being subdivided in defibering process; reconsidering coarse-screen baskets for strengthening dirt removal; removing color spots approached from defibering process and white water treatment process; reconsidering bleaching parameters for restraining brightness decrease.
  The conditions of waste paper market are changing at any time. This report contains the efforts under consideration. We aim to continue the efforts for stabilizing and upgrading the pulp quality.

Conference Report of the Cellulose and Renewable Materials Division in the 235th ACS National Meeting & Exposition

Takuya Kitaoka
Faculty of Agriculture, Kyushu University

  The 235th American Chemical Society National Meeting and Exposition was held in New Orleans, LA, USA on April 6-10, 2008. The ACS is the world's largest scientific society founded in 1876, and the 2008 spring national meeting gathered more than 13,300 attendees from all over the world. This conference report focuses on the interesting presentations in the Cellulose and Renewable Materials Division, especially Anselm Payen Award Symposium honoring Prof. Fumitaka Horii: Structure and Properties of Cellulosic Polymers, Assemblies, and Nanocomposites.

Evaluation of Chloroform Emission at an ECF Bleaching Pulp Mill

Keiichi Nakamata
Technical and Development Division, Hokuetsu Paper Mills, Ltd.
Youichi Motoe
Environmental Section, Niigata Mill, Hokuetsu Paper Mills, Ltd.
Hiroshi Ohi
Graduate School of Life and Environmental Sciences, University of Tsukuba

  Chloroform formation, balance, and discharge were estimated during 1997-2005 at an ECF bleaching hardwood kraft pulp mill that operated a complete airtight type activated sludge treatment using pure oxygen for the bleaching sewer. This was achieved by collecting and analyzing discharge water and gas samples that contained measurable levels of chloroform. During the stable operation of ECF bleaching, the average formation of chloroform was estimated to be 1.48 g/pulp adt. At the activated sludge treatment of chlorine bleaching sewer, chloroform generated being accompanied with decomposition of organic chlorine compounds indicated by AOX. It was suggested that the activated sludge treatment could remove or decompose the chloroform generated from ECF bleaching sewer.

Keywords: chloroform, bleaching, activated sludge, kraft pulp, hardwood