JAPAN TAPPI JOURNALVol. 57, No.9

September 2003 Abstracts


Improving Runnability of Papermaking Machine through Optimization of Wet-end Operation
Koichi Tadaki, Munetoshi Yamaji, Tomoko Asada and Kenji Tsunekawa
FC Process Department, Somar Corporation

　Under world-wide increasing concerns for environmental issues and as an influence of the trend toward neutrality of papermaking conditions, difficulties are being added to the paper stock situations year after year. Increased mix of deinked pulp or coated broke not only deteriorates the wet-end properties such as fiber retention and drainage and paper quality such as paper strength, sizing, etc., but also is responsible for stain troubles in papermaking equipment. Countermeasures against stain on a papermaking machine are currently one of the major problems for improving productivity and runnability. In a papermaking machine system, slime troubles due to microorganisms and foreign matters such as pitches, anion trashes, etc. are sources of stain in correlation each to the other. It is believed therefore that a possibility would be accomplished for improvements of productivity and runnability by totally addressing these matters together and by undertaking rapid and adequate action therefor.
　By utilizing the know-how accumulated over years for handling microorganisms with a slime controlling agent as the center item and the experience relative to "Realizer" as a wet-end improver which addresses foreign matters such as pitches and anion trashes, we are making various proposals for countermeasures against stain troubles in a papermaking machine addressed totally and analyzed as a comprehensive matter.


Continuous Analysis of Suspended Materials Gives BetterControl of Pulp and Paper Processes
Chiaki Benitani
Spectris Co., Ltd., BTG division

　This paper deals with an optical method for continuous analysis of suspended materials. It will find its main use in the pulp and paper industry e.g., for the analysis of pulp, white water and effluents from a mill. The instrument is based on the transmit measuring method. One of the unique features of the instrument is the possibility to simultaneously obtain separate values for the large particle (fibers) and fine particle content (fillers/fine) of the suspension. Changes in particle size will therefore have practically no influence on the total consistency measurement. This is normally a large problem for optical consistency meters, especially instrument for the measurement of turbidity.
　The sensor is based on fiber optics and its design guarantees high reliability with a minimum of maintenance. Clogging of the measuring gap is practically impossible. Furthermore, the sensor is equipped with a device for automatic cleaning. This means that the measurement neither will be affected by variation in light intensity nor by contamination of the optical surface.
　These analyzers have been installed, in different positions in the pulp and paper industry, with good experience. After presenting the great advantages of the measuring method, this paper will then explain different applications and mill installations.


Anoinic Trash in Papermaking: Mechanism and Approach
Jiayi Chen
Kurita Water Industries Ltd.

　Anionic trashes (AT) are released into the water phase from contaminated reused water, recycled fibre, or broke, and form deposits at papermaking process including the wet-end, press section, machine fabrics and rolls. The AT can cause lowering of productivity by defective products; sheet breaks; short shutdown duration.
　The lab and field trials showed that troubles from AT can be controlled by dosing cationic fixing chemicals. This paper examines: the mechanism of troubles from AT, variable wet-end factors, selection of the most compatible additive; and monitoring machine performance.


ProRelease Stabilizer- Gentle web run -
Yukinori Takano
Voith IHI Paper Technology Co., Ltd.

　Since its introduction, single-tier dryer section - equipped with DuoStabilizers and ropeless tail threading technology - has proven extremely successful. The complete single-tier TopDuoRun is now the preferred dryer section configuration, especially for high-speed paper machines and lightweight paper grade. Furthermore, in combination with double-tier dryer groups - the CombiDuoRun - for heavy grades and at somewhat lower speeds, it permits high runnability through stable web run and reliable, fast tail transfer.
　The newly developed and already successfully installed ProRelease Stabilizer now offers further optimization potential in the particularly sensitive area of the first dryer groups by reducing the required tension of the still wet weak paper web during detachment from the dryer.


Introduction of Ronningen DCF Filter
Hisashi Kitano
ITOCHU Sanki Corporation

　We started our relationship with RPA Process Technologies which are producing well known RONNINGEN-PETTER filters in United States in year 1998. As you may know, RONNINGEN filter is one of the best filter in the world in liquid filtration from the Wet End to the Coater. The filter which we are introducing here is built with the most recent technologies that the filter does not need to be back washed when operating as well as the traditional concept of the RONNINGEN filter.


Mechanism of Sizing Behavior of ASA
Kunihiko Matsushima, Manabu Takaoka, Hirofumi Zako, Yuki Sakamoto and Yoshio Adati
Chiba Laboratory Research and Development, Seiko PMC Co., Ltd.

　Alkenyl succinic anhydride (ASA) is well known as one of the synthetic sizing agents widely used in neutral papermaking and its role at higher pH range sizing has become important because of environmental issues, the lifting ratio of recycling pulp, anion trash increase in papermaking system and so on.
　Although many literatures on ASA have been published, we studied the mechanism of ASA sizing by using both ASA and ASAcid (hydrolyzed ASA) in order to obtain further comprehension. In this experiment, sizing treatment was carried out under ideal conditions where the filter paper was immersed in ASA emulsion or in the toluene solution of ASA, so as to retain the same quantity of sizing material in filter paper. The same procedure was adopted in the case of ASAcid. Contrary to our expectations, the most notable fact from the results obtained is that the sizing effect of the filter paper treated with ASA emulsion is superior to that of ASA toluene solution.
　These results suggest that the most essential factor to develop sizing is morphology of sizing material distribution on fibers. We speculate that the entirely uniform distribution of sizing material, like a uniform thin film, is not necessary for sizing development but the scattered distribution, like dots, is required.


Development of Longlife Suction Box Lip
Ryo Shimizu and Norio Fujita
Nomura Plating Co., LTD.

　A felt suction box is installed in the press section on a paper machine. It is useful for removing white water and shower water for felt cleaning by effect of vacuum. Our company developed of sprayed suction box lip that is a round type at 1997. We started the development of longlife sprayed suction box lip that is a flat face type for longlife , lower price and lighter. Suction box lip combined a resin body and spraying material on stainress steel. Result of fundamental experiment , we chose special phenolic resin and FRP from resin and epoxy adhesive from adhesive. We examined WC−NiCr spraying , Cr2O3 spraying , Al2O3−TiO2 spraying , ZrO2 spraying , Ni−P plating dispersing SiC, Ni−W plating , Cr plating and sintered Al2O3 by referring the result of taber abration test. After the wear resistance examination , we understood the followings by evaluate the lesswear , damage of felt , scratch on lip surface. Regarding for wear, WC−NiCr spraying and Al2O3−TiO2 spraying are superior than other samples. Al2O3−TiO2 spraying is the most suitable about wear resistance and spraying thickness. On the other hand Cr2O3 spraying is the most suitable about effect of less felt damage.


The Development of Stainless Steel Weld Overlaying for Continuous Digesters
Masaaki Ito
Daio Maintenance Co., Ltd.

　We have developed an overlay method for continuous digesters that substitutes the lining of stainless steel plates. We carried out the overlay (110�u) at the NKP Continuous Digester in Daio Paper Co., Ltd. in March this year.
　The superior points of our overlay method are the high welding quality achieved by using new automatic welding machines, the short term of the work and the high safety level for assembly, inspection and dismantling that employed an automatic scaffolding system.
　Our method of overlay is capable of preventing corrosion of the welded parts that stainless steel lining plates have and corrosion of the cladding of continuous digesters.


New Agents for Kraft Process
Keigo Yoshiuchi
Research & Development Dept., SAN NOPCO LIMITED

　The Kraft process consists of the cooking process and the bleaching process mainly. In Kraft process, the weakest point is the low of the yield of pulp in the cooking process. The kinds of quinone derivatives or polysulfide derivatives are widely used as cooking assistant agents to improve it. "Cooking Accelerator" is the agent to accelerate the function that these agents have and to raise the yield of pulp furthermore.
　In the bleaching process, chlorine is used as one of the bleaching agents. But it may cause the occurrence of dioxin, so it is better to decrease the amount of chlorine consumption from the environmental point of view. "Oxygen Bleaching Accelerator" can raise the ratio of delignification yield and decrease the amount of not only chlorine but also sodium hydroxide and chlorine dioxide.
　Both agents are useful in the Kraft process, and can be expected in the future.


Next Generation Color Control- Its Strategy and Results -
Kazumasa Hasumi
Sales Department, Honeywell K. K.

　Paper manufacturers and end-users have become more critical about shade variation and product appearance. These requirements span the entire grade structure from tissue to multilayer board, including the whites through to deeply dyed grades. While invisible quality variables, such as basis weight, moisture and caliper may be undetected although well outside specifications, small differences in shade can be easily detected by a relatively untrained eye, potentially resulting in substantial product rejection. The requirement for minimum color variation in paper products has forced papermakers either to maintain a group of operators whose time is nearly 100% dedicated to controlling product color manually, or to implement closed-loop color control. Over the past twenty years, the popularity of supervisory closed-loop color control has increased significantly and has produced excellent results.
　In a push for greater efficiency, the industry has been seeking ways to reduce color change times and resultant broke losses. Typically, manually controlled color changes can require up to one hour, depending on the complexity of the change. Today's trends toward reduced inventories and faster delivery to paper customers denies papermakers the luxury of scheduling a well-established progression of shades and forces shorter production runs of each shade, resulting in frequent, more difficult shade changes.
　As the new solutions for above requests, the Honeywell new color controls provide robust models which are both responsive and capable of maintaining the color coordinates closer to target than ever before.


VERIS Power & Environment Monitoring System Real Time Monitoring & Analyzing System by PC
Hiroyasu Hattori
Nittou Shoukai Ltd.

　Veris Industries has the sensors and systems for building, factory control and automation: patented current sensor with integral relay, microprocessor controlled and analog current sensors for variable frequency drives, power meters, energy management meters, Modbus data acquisition products, humidity (RH) sensors, temperature sensors, carbon monoxide (CO) detectors, carbon dioxide sensors for monitoring indoor air quality, pressure sensors, electropneumatic pressure controllers, combination sensors for humidity/temperature/carbon dioxide measurement, power supplies and accessories.VERIS has developed Power and Environment Monitoring, Energy Saving systems using these sensors. We introduce VERIS real time Power and Environment Monitoring, Analyzing Systems using PC.


Reduction of Chloroform Emission from Hypochlorite-bleaching Process
Kengo Magara, Olov Karlsson* and Shuji Hosoya
Department of Chemical Utilization, Forestry and Forest Products Research Institute

　Chloroform was readily converted to formic acid through the nucleophilic attack of hydroxyl anion under the certain reaction conditions ( pH > 12, temp. > 70 ℃). When guaiacol was reacted with hypochlorite at such reaction conditions, the generation of chloroform was almost completely reduced. Successful reduction of the chloroform generation was also observed in alkaline hypochlorite bleaching of kraft pulps and DIP without any loss in pulp quality.
　Even when the hypochlorite bleaching was carried out under the open system (no sealing of the reaction vessel), nearly 90% of the generated chloroform was converted to formic acid.

Key words: chloroform, alkaline hypochlorite, bleaching, dehalogenation.


Stress Analysis for Gripe Hole of Corrugated Fiberboard Case- Relation between Hole Breadth and Stress Components -
Satoru Matsushima
Guest Professor, Research Center of District Corporation, Ehime University
Shigeo Matsushima
Professor Emeritus, Ehime University

　An elastic analysis for side plates of the corrugated fiberboard case (breadth L=240〜302.5mm, height 207.5mm and length 440mm) with grip holes (length ΔL0=0.0〜62.5mm of parallel line, hole side radius r=12.5mm of semicircle arc) applied uniform applied stress p in ΔL0 range was performed by finite element method, and from this analysis, stress components of their plates were considered.
　Large absolute values of normal stresses σｘ and σｙ in breadth and height directions and shear stress τｘｙ concentrate near upper edges and sides of holes. Maximum of │σｘ│ is at centers of hole upper edges in ΔL0<1.6r and at centers of plate upper edges in ΔL0>1.6r, and maximum of │σｙ│ is at centers of hole upper edges in ΔL0<1.6r and at hole sides in ΔL0>1.6r. And τｘｙ is negative value and maximum of │τｘｙ│ is at centers of hole upper edges in ΔL0<1.6r and at positions r/2 along upper direction from hole sides in ΔL0>1.6r. Maximum values for σｘ and σｙ increase and maximum absolute values for minimum σｙ decreases with the ΔL0 increase, and maximum absolute value for minimum σｘ and τｘｙ decrease initially and increase with the ΔL0 increase.

Keyword: Computational Mechanics, Structure Analysis, Elastic Bending, Strength of Corrugated Fiberboard, Elastic Stress Analysis, Structure Strength,Numerical Analysis, Stress Concentration