2003 Jun JAPAN TAPPI JOURNAL

 

JAPAN TAPPI JOURNALVol. 57, No.6

June 2003 Abstracts


Kraft Cooking with SAQ Suitable for ECF Breaching
Junji Tanaka
Kawasaki Kasei Chemicals Ltd.

 SAQR has been used as a cooking additive in many KP mills. This process is known as "Quinone Cooking". In this paper, some new applications of SAQR’s functions are proposed when ECF bleaching process is introduced in pulp mills.
 First, the effect of SAQR, which decreases bleaching load keeping pulp yield and strength by lowering Kappa number, is explained. Also, SAQR’s advantage comparing with dispersed AQ is mentioned, especially when SAQR is used combining with Polysulfide cooking. Finally, KKC’s study plan about SAQR’s applications to recent modified cooking processes is described.


ECF Bleaching of Softwood and Eucalyptus Pulps−a Comparative Study
Lennart Meuller, Jiri Basta, Lillemor Holtinger and Gerd Wane
Eka Chemicals AB, S-445 80 Bohus, Sweden

 This paper deals with a comparison in ECF bleaching and effluent characterisation of kraft pulps based on softwood and eucalyptus. The study is made for both conventional and oxygen delignified pulps.
There are similarities in the bleaching of softwood and eucalyptus looking at the bleaching parameters. In mill scale there are however normally differences in the number of bleaching stages for conventional and oxygen delignified pulps when bleaching to
90 %ISO brightness. Conventional pulps are mainly bleached in a five stages sequence with peroxide reinforcement in the alkaline stages, D (EOP) D (EP) D. Oxygen delignified pulps are mainly bleached in a four stages sequence, D (EOP) D D, especially softwood pulps. A three or four stages sequence, D (EOP) D D or D (EOP) D, is usually used when bleaching oxygen delignified eucalyptus pulps. For brightness levels of 88 %ISO a three stages sequence can be used for both oxygen delignified softwood and eucalyptus pulps.
In the ECF bleaching optimisation study we have used a five stages sequence for all pulps. The same bleaching sequence was used in the effluent characterisation study except for the oxygen delignified eucalyptus pulp where a three stages sequence was used.
 Combined effluents from all bleaching stages were characterised and exposed to biological
 treatment. Characterisation studies were carried out both prior to and after the biological treatment.
The characterisation of the main COD components; lignin, carbohydrates, methanol, low molecular acids and extractives prior to and after external treatment, corresponded well with the calculation of the total organic composition. The results showed that the organic composition varies for effluents from different pulps.
The COD composition of softwood and eucalyptus effluents were significantly different, which explains why the effluents from the eucalyptus pulps were more biodegradable.

Keywords; Bleaching, ECF, softwood, eucalyptus, COD, AOX, Effluent characterization,


New Refiner & Disperser Providing a Principle of Conical Refiner-DoubleConifiner & ConiDisc-
Kazuo Aoshima
Aikawa Iron Works Co., Ltd

 The DoubleConi-Finer is the latest designed refiner having both characteristics, double disc type refiner and conical type refiner, which is used for low consistency refining. The ConiDisc is one of the high speed disc type dispersers, which is used as a disperser for hot dispersion system and is also used as a high consistency refiner. It provides two kinds of fillings, one is conical type, and the other one is disc type which is fixed at outside of the conical type fillings. Those refiners having unique design improve dramatically paper characteristics and energy consumption. This paper reports the constructions and the benefits of those new refiners.


Energy Saving RTS-TMP Pulping and its Pulp Quality
Masahiro Ohkubo , Tamio Fukuzawa and Chiaki Kawakami
Andritz K.K.
Brad Cort and Marc Sabourin
Andritz Inc.

 RTS is a new Low Retention, High Temperature and High Speed TMP pulping method developed by Andritz. While the pulp quality is kept the same as conventional TMP, the energy is 15-17% less than the conventional TMP.
 Extensive studies were conducted to evaluate the development of pine pulp properties and energy requirements using two different thermomechanical refining processes at a southern U.S. paper mill. The processes included both a low intensity (TMP) and a high intensity (RTS? ) refining configuration. The pulps produced with the RTS process had 15%-17% lower energy consumption compared to TMP pulps produced at similar freeness and handsheet physical properties. Despite similar average fiber length results between the two processes, the low intensity pulps had a higher percent by weight of fiber retained on the Bauer McNett 14/28 fractions, whereas the high intensity pulps had a higher percent by weight retained on the middle fractions. Calendered newsprint produced from the high intensity pulp had a lower roughness, which may be related to the lower fiber size distribution. Light was thrown on this finding by porometry measurements of the newsprint, which revealed a slightly lower pore size distribution from paper produced with the higher intensity pulp. Standard ink printing tests, however, provided similar results between newsprint paper produced from the TMP and RTS? processes.


Applying Automatic Chemical Control from Stock Prep to the Machine
Roland Berger and Lydia Christen Bley
Muetek Analytic GmbH
Kenichi Ishihara
Spectris Co., LTD. BTG division

 For many years, retention-aid dosage has been controlled by the white water consistency in newsprint, fine paper and board applications. This control strategy is well known and has proven efficient and beneficial. However, combining retention-aid control and charge demand control with coagulant or fixative in the thick-stock area provides additional benefits.An on-line charge analyzer, measuring the incoming furnish charge level, allows controlled coagulant addition so that downstream additives are applied more efficiently and economically. This control strategy provides substantial cost savings to the mill. Costly functional additive consumption is reduced and other chemical control loops, such as retention-aid addition, are improved.
 This paper explains the impact of white-water consistency on paper machine outcomes such as basis weight variation, steam consumption and wet-end stability. White-water consistency, dewatering and charge demand control approaches are discussed, and practical examples are used to describe how short circulation and chemical composition of the pulp affects final product quality. Mill experiences with the on-line units, and proposed gains and benefits of these measurements to papermakers will be demonstrated.


Introduction of a New Type Filter for White Water
Tomohiro Takahashi
Ebara Corporation, Environmental Engineering Group

 For the recycling of white water from papermaking, several kinds of techniques have been developed and put into practical use, but mainly, sand filtration has been adopted up to present for the reason that it provides good water quality stably. However, with the conventional white water filters, problems occurred in the maintenance and management of operation, such as clogging of filter layers, slime troubles, etc. caused by mud ball formation. In order to solve these problems, EBARA has developed a new type filter provided with a surface washing agitator which allows, during backwashing, the sand particles in the filter layer to be cleaned by strong rubbing against each other. An outline of this machine is introduced below.


Diagnosis of Microbial Problems on Paper Machines
Linda R. Robertson
Principal Consultant Paper Microbiology ONDEO Nalco Co., Ltd.
Yasumasa Ishii
Senior Account Manager ONDEO Nalco Japan Co., Ltd.

 Numerous microbes are capable of growth in paper machine systems. They form visible deposits that result in sheet defects, holes or even breaks in the web. Microbes are also responsible for performance loss and spoilage of pulp and expensive functional chemicals. This spoilage can lead to strength loss in fibers, formation of odors that result in rejected products, viscosity loss in starch and a variety of other problems. Diagnosis of microbial problems in complicated by the fact that simple aerobic plating techniques on tryptone glucose extract agar or PetrifilmsTM with a 48-hour incubation period do not allow recovery of all of the microbes causing the problems. Nor do the numbers of planktonic (free-swimming) cells correlate to the severity of deposition on surfaces. This paper will discuss the limitations of generally accepted plating techniques and propose more accurate diagnostic methods for solving microbial problems.


Increasing Productivity by Investing in New Technology- On-line Concepts for Different Paper Grades -
Hiroshi Fujiwara
Sumitomo Heavy Industries Techno-Fort Co., Ltd.

 Running references prove that on-line technology can improve productivity through lower costs and investments. Operating and technical demands are higher, but they can be handled with good cooperation and hard work. Every project is individual in terms of its demands and potential.
 This means that on-line and off-line technology have to be considered case by case in accordance with project targets and local factors such as furnish. When applicable, on-line technology is one of the most promising options for productivity improvement.


Mitsubishi MCCR / MJ Calender
Setsuo Suzuki
Mitsubishi Heavy Industries, LTD., Hiroshima Research & Development Center

 Mitsubishi Heavy Industries, LTD. (MHI) has developed a high performance controlled multishoe crown roll to control the caliper cross profile and MJ calender applied the technology from shoe press. Recently better surface for high quality printing and bulky paper for saving pulp consumption are required. MCC roll and MJ calender meets these requirement. This paper introduces outline of MCC roll and MJ calender and shows data from the pilot trial and field.


A Study of Sheet Gloss
Eisuke Shiiyama
Latex Research Center, Nippon A&L INC.

 Recent years, requirement for sheet gloss of coated paper is steadily developing because it is one of influential factors deciding the final quality of coated paper.
 In this paper, the relation between sheet gloss and the effective factors such as surface roughness or optical properties was studied. Coated paper samples were prepared with different latex binder types or different pigment systems, then several types of surface roughness or optical properties were measured in order to understand which property is more influential to sheet gloss.
  The concluding remarks gave the following understandings.
 Firstly in surface roughness measurement, although both the average roughness Ra and the average wave length of roughness frequency Sm gave good correlations with sheet gloss, the later was more influential. In addition, it could be understood that surface roughness was affected by a degree of kaolin orientation.
 Secondly in optical property measurements, the ratio of incidental reflectance to the total reflectance including diffusion gave a liner correlation to sheet gloss, the higher ratio gave the better sheet gloss.


Improved Two-Drum Winder Technology
Peter Trilling
Voith Paper Jagenberg GmbH

 Today many Paper Mills have to supply rolls at larger diameters to their customers. Very often the existing two drum winders cannot cope with the quality demands as larger roll diameters lead to increased roll weight and therefore higher nip pressure between roll and drums.
 Excessive nip pressure results in various roll defects. So paper mills are forced to improve their winder technology. Ideally rebuilt packages for the existing winders should make the winder matching with their future demands.
 Voith Paper Jagenberg GmbH can offer tailored solutions for many applications by supplying special roll covers which reduce the specific nip pressure.


The Stable Flow Measurement for Stock Flow by Capacitance Magnetic Flowmeter
Takashi Okada, Jun Nishimura and Seiji Tanabe
Yokogawa Electric Corporation

 The stock feed flow from stuff box is very important factor to decide the quantity and the quality of paper. Usually magnetic flowmeters are used to measure the stock feed flow and the accuracy mainly depends on the uniform of the conductivity and gas fed with stock from stuff box at the start up action. We developed the capacitance type of magnetic flowmeter and tried this meter to the line in a series of the wet electrode type of magnetic flowmeter. The capacitance magnetic flowmeter measurements are very stable and the outputs of both flowmeters are quite different. This paper shows the state-of-the-art technology on the stock flow measurement and describes the advantage for the use of capacitance magnetic flowmeters.


Facility Diagnosis of Acoustic Signal−Acoustic Diagnosis Technology and Application Case−
Shinsuke Terashima
Automation Asset Management Department, Yamatake Industrial Systems Co., Ltd

 IF-ASSET is abnormal signal segregation and detection technique that was developed based on inverse filtered acoustic/vibration signals, and was proven effective in monitoring rotary machines, compressors, piping and high pressures vessels. Now we intend to utilize IF-ASSET to monitor several kinds of industrial machines.


Preparation and Evaluation of Mordants for Neutral
Rosin Size Emulsion from Lignin
Yasuyuki Matsushita and Seiichi Yasuda
Graduate school of Bioagricultual Science, Nagoya University

 Mordants for neutral rosin size emulsion from lignin were prepared and their abilities evaluated. To convert lignin into the mordant, an amino group was introduced to lignin by Mannich reaction and the reaction with glycidyltrimethylammonium chloride (GTA). In this study, Kraft lignin and phenolated sulfuric acid lignin (P-SAL) were used. In an experimental system composed of the handsheets made with LBKP, sizing agent and lignin derivatives, a Mannich reaction product prepared from Kraft lignin failed to exhibit any mordant characteristic, whereas Mannich reaction products (MP-SAL) prepared from P-SAL were highly effective as mordants. MP-SAL with ethylamino group especially showed higher performance. The MP-SAL with the higher pKa value of the introduced amino group also had higher performance. In the rosin emulsion-alum system, MP-SAL and GP-SAL, which latter are reaction products of P-SAL with GTA, enhanced the sizing effectiveness under acidic to neutral pH range. The handsheets prepared with MP-SAL or GP-SAL besides alum still showed the sizing effectiveness after chloroform extraction, although the sizing effectiveness of the handsheets prepared only with alum disappeared after chloroform extraction. Thus, these results suggest that the enhancement of sizing effectiveness contributed to greater association between the size and the fiber surfaces with the addition of MP-SAL or GP-SAL. A decrease in brightness was observed when MP-SAL or GP-SAL was used as a mordant. According to the Kubelka-Munk theory, the brightness of original pulp with 85% brightness was calculated to decrease 16.9% and 4.3% by adding 0.2% MP-SAL and 0.2% GP-SAL, respectively, but the brightness decrease of a pulp with 50% brightness by adding 0.2% MP-SAL and 0.2% GP-SAL was only 1.9% and 0.6%, respectively. This suggested that the lignin derivatives are as capable as a mordant in newspaper and mechanical papers, which do not require a high level of brightness.

Keywords: lignin, sulfuric acid lignin, rosin size emulsion, mordant, Mannich reaction, epoxy reagent


Study on the Dispersion Stability of the Two Components Slurry, Composing from SAP and MFC (Part III)Study on the Composite Structure of SAP and Microfibrillated Cellulose
Migaku Suzuki
Japan Absorbent Technology Institute
Gyosuke Meshitsuka
School of Agricultural and Life Sciences, The University of Tokyo

 A dispersion liquid can be obtained exhibiting a high viscosity at a low concentration by uniformly dispersing microfibrillated cellulose (MFC) or bacterial cellulose (BC) in a mixed medium of water and hydrophilic organic solvent.
 Particulate SAP as dispersed in this dispersion liquid, SAP particles can be stably dispersed with a high concentration in the dispersion liquid by virtue of the viscosity exhibited by MFC. In addition, possible coagulation and recoagulation to be caused with SAP particles otherwise coming near to each other can be almost entirely prevented by the SAP particles being dispersed in the dispersion liquid by the action of the dispersion of MFC, so that a dispersion slurry of a long and stable pot life can now be prepared.
 The respective behaviors of SAP and MFC in such mixed medium have been reported in Part I of "Study on the Composite Structure of SAP and Microfibrillated Cellulose", "Swelling & Coagulation Behaviors of Acrylic Acid Base SAP in Water & Water Miscible Organic Solvent Mixture" 1) and in Part II "Study on the Dispersion Stability of the MFC or the BC in a Solvent Mixture of Water and Organic Solvent" 2) in this Journal.
 As reported previously, the authors believe that they have made clear the nearly whole picture of the conditions for stably dispersing each component, SAP and MFC, alone in a dispersion medium. When it comes to a two component slurry system of SAP and MFC in coexistence, various unexpected phenomenon come to take place caused by the concentrations and concentration ratio of SAP and MFC, their different mixing mechanisms, changes with time, coating conditions, etc. In this report, studies have been made on the process flow of SAP and MFC being added and mixed, their dispersion limits, stability with time of their mixed slurry, stability at their temperatures, etc. so that the following results have been obtained:
  1) It is found that MFC has the following effects in the slurry of SAP and MFC in coexistence:
.MFC even if at low concentrations prevents coagulation and re-coagulation of SAP by virtue of its high viscosity;
.MFC being dispersed keeping a finely particulate shape prevents bonding in groups of SAP particles to each other;
.While SAP tends normally to swell to 1.5 to 2.2 times larger than its original form as it selectively absorbs water in a dispersion medium, it is prevented by MFC in coexistence from swelling with MFC retaining water out of the dispersion medium by virtue of its high hydrating property; and
.MFC prevents the selective water absorption of SAP so as to cause the dispersion
 medium not to undergo changes in composition for a long period of time.
 2) The optimization of the preparation conditions of subject slurry contemplated in a commercial process:
.In a procedure of preparing a slurry, a dispersion liquid of MFC should be first prepared and then SAP is to be added;
.SAP has been found to be wide in its stable dispersion region if it is such as cross linked on the surface, of spherical shape, of small particle diameter and is obtained by being reversed phase suspension polymerization;
.The limit concentration of SAP in coexistence with MFC is 20 to 40 %;
.The limit concentration of MFC in coexistence with SAP is 0.4 to 1.0 %;
.Possible change with time of the slurry with MFC in coexistence can be prevented by properly selecting SAP and the water content of the dispersion medium and keeping the concentration of around 15℃.
 3) It has been found that the conditions of stably forming sheets can be established by defining a range of conditions for stabilizing the slurry.

Keywords:SAP, MFC, SAP/MFC co-existence slurry, partial swelling of SAP, dispersion condition, sheet formation condition