Vol.66, No.10 Abstracts

Chemistry of Delignification in Pulping and Bleaching

Tomoya Yokoyama
Laboratory of Wood Chemistry, Department of Biomaterial Sciences,
Graduate School of Agricultural and Life Sciences, The University of Tokyo

  Most of the principal delignification reactions in pulping and bleaching are described in various books related to wood chemistry and published by Japan TAPPI. In this report, these reactions are primarily reviewed, and several valuable reactions are described. Then, the recent results about pulping and oxygen bleaching obtained in our laboratory are introduced.

Cooking Technologies of Digesters for Producing Kraft Pulp

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

  With development of the theories for kraft pulping, a number of cooking technologies of digesters and cooking processes such as MCC, ITC, and BLI which based on the theory proposed in 1980s were developed. On the other hand, COMPACT COOKINGTM G1 and G2 cooking systems which based on the theory proposed in 1990s were also innovated. COMPACT COOKINGTM G2 system can 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.

ADVANCED TMP - Enhancing Fiber Development at Reduced Energy Consumption

Peter Braeuer and Johann Grossalber
Andritz AG, Austria
Marc Sabourin
Andritz Inc, USA
Tamio Fukuzawa
Andritz K.K.

  A method for producing well-bonded thermomechanical pulps, herein named ATMP, from several softwood species at significantly reduced energy consumption is presented using a combination of TMP sub-processes and targeted chemical treatments. The ATMP technology consists of unit operations formulated to better separate the defibration and fibrillation steps with the goal of improved pulp fiber bonding at the lowest possible energy consumption; targeted chemical treatment is an important subcomponent for maximizing the efficiency of this process. The sub-process of chemical treatment is presented from a series of pilot studies evaluatingG i) sodium bisulfite treatment, ii) location of chemical application, iii) sodium bisulfite charge and iv) type of chemical agent applied. The impact of bisulfite pretreatment on alkaline peroxide bleaching is also presented. The results confirm that bisulfite is an effective chemical agent for enhancing the ATMP process, and its performance is optimized by both, the location of chemical treatment and charge on O.D. fiber.

Today's Subjects of Domestic DIP Plant and Its Solutions

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

  After the big earthquake, power shortage due to shut-down of the almost all of nuclear power plant is giving a serious damage to our pulp & paper industry. Again this summer, we have to survive in extreme environments. DIP is good for the ecology originally because using waste paper and not need much tree cutting. But now additionally it is required more direct contribution of reducing the electric power consumption as much as possible.
So far, AIKAWA Iron Works has developed a lot of the most-advanced DIP facilities and lower power consumption systems under cooperation with users. For examples; the combination system of HeliDisc high consistency pulper & Double Dumping Screen which has superior pulping action, coarse impurities removing and ink dispersion effects. Ultra low power consumption MaxFlow & GranFlow screens for coarse & fine stages. HyperCell which has all good points of past floatators. 4 shafts UV Breaker & ConiDisc hot dispersion system which required for high brightness.
In this report, we would try to introduce additional equipment and systems as the countermeasures to this crisis. i.e. Continuance high consistency pulping system, Fractionating DIP system, applications of Flexible cascade cleaner system & HyperCell, Advanced MAXWave screen cylinder and Ultra low intensity post refining system.

Operating Experience of Co-Firing of Petroleum Coke System in Lime Kiln

Satoshi Hasegawa
Nichinan MillCOji Paper Co., Ltd.

  Oji Paper Nichinan mill has two rotary lime kilns in recausticizing process of kraft pulp plant, No.1 lime kiln(2.3m~50mL) and No.2 lime kiln(2.1m~36.5mL). Since waste derived fuel boiler was installed in 2006, the lime kiln was the only process to use heavy oil in the mill. In order to reduce heavy oil consumption, we installed petroleum coke co-firing system on the lime kiln in 2008. Some troubles happened at the start-up, but now this system is running very well and has brought large economic effects.
  This paper shows the operating experience of co-firing of petroleum coke system in lime kiln.

Operating Experience of Hyper-Cell Floatator

Tatsumi Hosaka
Hokkaido Mill-Yufutsu, Nippon Paper Industries Co., Ltd.

  In Japan, the utilization rate of recovered paper reached 63% in 2009. Except paper board, ONP is mainly used for recovered paper. Since news paper quality, such as ash content, has been changed, ash and microsticky removal is required, especially at the floatation process for paper recycle. In order to improve DIP quality and promote further use of DIP, Aikawa iron works and Nippon Paper Industries developed the state-of-the-art floatator gHyper-Cell floatatorh and installed in Hokkaido Mill-Yufutsu. This report introduces our operating experience of Hyper-Cell floatator.

The Measure of a Bad Smell Improvement of Kraft Pulping Process

Hiroshi Fujita
Niigata Mill, Hokuetsu Kishu Paper Co., Ltd.

  Since Niigata Mill, Hokuetsu Kishu Paper Co., Ltd is being located in the central part of Niigata, it is very sensitive to an environmental trouble. In response to past various environmental troubles, the environmental impact prevention regulation based on ISO14001 was enacted in August, 2011. In this news, the bad smell sensor employment method of the circumstances where it resulted in environmental impact prevention regulation establishment, or the Niigata factory, the environmental trouble example in KP process, and a bad smell measure example are introduced.

The Bamboo Pulp Production by Batch Digester

Yoshitaka Fuse
Pulping section , Sendai Mill, Chuetsu  PulpPaper  CoDLtd.

  Kagoshima Pref., where the Sendai Mill is located, has the largest bamboo forests area of 16,000ha in Japan, and typical species named Moso bamboo covers an area of 7,600haD
Since well controlled bamboo forests produce a good quality of bamboo shoot, bamboo older than five years need to be trimmed every year in order to maintain the forest quality. However most of the trimmed bamboo has been left in the forest usually, it has been an issue how to utilize such abandoned bamboo.
  Sendai mill has been utilizing such trimmed local bamboo since 1999 as raw material for paper production, in order to protect local forest environment and to contribute prevention of global warming. We upgraded the batch digester system pulp line for small lot production into ECF pulp production plant, and this upgraded line has started production in 2010 and the trimmed bamboo is utilized more effectively. We introduce our experiences on the bamboo pulp production.

Analysis and Countermeasures against Stickies Occurring at Deinked Pulp Process

Hiroshi Ougiya
Hachinohe Mill, Mitsubishi Paper Mills Limited

  In Hachinohe mill, deinked pulp (DIP) with high brightness is produced. The pulp is mainly made of sorted colored ledger. However, the procurement of sorted colored ledger has become difficult by the rising price of all over waste paper. Therefore, we are forced to use several types of waste paper such as waste magazine. With the increase of usage of waste magazine, quality trouble caused by stickies was increasing.
  To reduce the stickies, we analyzed the DIP process and characteristic of the stickies. The stickies become small through the process not only by shearing force but also by chemical function. Much stickies was removed by screening than by floatation, but we recognized that the floatator was able to remove problematic stickies. As a result, improvement of removal of the stickies by floatation induced achievement of decrease of the quality trouble.

Chemical Pulp Fiber Line Optimization

Naoto Takigawa
Metso Automation, Process Automation Systems

  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.

Utilization of Lignin Obtained by Separation of Wood Components

Yasumitsu Uraki
Research Faculty of Agriculture, Hokkaido University

  To establish chemical biorefinery for woody biomass, it is very important to convert lignin into value-added materials in addition to its use as an energy source. In this report, I would like to introduce its conversion to several valuable, functional materials on the basis of our recent research.
  The first example is lignin-based carbon fibers (CF). In their production, spinning is a first process. There are proposed two methods, melt spinning and electro-spinning. The latter method for lignin was reported in the last decade. The second process is thermostabilization. The resultant lignin fibers prepared by both methods have high thermal mobility, such as glass transition and thermal flow. Thereby, the fiber morphology is changed by direct carbonization. To prevent morphological change, the thermostabilization process is very important. However, it is a tedious and time-consuming process. We developed a novel type of lignin fibers, which was easily converted into thermally stable fibers by the treatment with concentrated hydrochloric acid for 2 hs. The final product, CF, prepared from the lignin fibers had comparable tensile strength to lignin-based CF reported previously.
  The other example for lignin-based functional materials is amphiphilic lignin derivatives, which are obtained by the reaction of isolated lignins or kraft black liquor with epoxylated polyethylene glycol. When these lignin derivatives were added to a saccharification medium using cellulase, the enzymatic saccharification efficiency was improved and residual activity of cellulase was maintained at a higher level. In addition, one type of the amphiphilic lignin derivative also had a superior ability for the cement dispersion to commercially available lignosulfonate that is well known as a cement dispersant.

The Present and the Future in Paper Electronics Using Printed Technologies

Masaya Nogi and Hirotaka Koga
Laboratory of Cellulose Nanofiber Materials, The Institute of Scientific and Industrial Research, Osaka University

  Recently, a low-environmental-load method called gprinted electronicsh has attracted much attention. By this method, electronic devices are manufactured on polymer substrates using high-volume and high-speed printing technology, similar to printing of newspapers or magazines. Since the electric components are mounted on flexible substrates, printed electronic devices are rather lightweight and flexible to be carried around, offering high mobility. Moreover, the method of printed electronics enables the production of electronic devices of various sizes\from a tiny palm-sized device to a large-area device meant to be put up on a building wall, for example, e-books, solar cells, organic light-emitting diode (OLED) lightings, digital signatures, RFID tags, and health care sensors. Cellulose nanofiber sheets or paper have great potential as PE substrates because they have high transparency (similar to glass and plastics), high thermal stability (similar to glass), and high foldability (similar to traditional paper). In this article, the author introduced some applications of cellulosic paper in the electronic devices.

A New Technology of Process Water Treatment Using Fluid-jet Cavitation

Takaharu Noda, Hiromichi Tsujia and Shisei Goto
NPi Research Laboratory, Nippon Paper Industries Co., Ltd.

  A new technology using fluid-jet cavitation (CV-jet) has been developed in order to improve the quality of secondary fibers. CV-jet treatment was applied to process water in deinking. In this treatment, process water was injected into the reacting vessel by using a high-speed jet and cavitation bubbles were generated around the jet. The impact force produced by the collapse of the cavitation bubbles detached contaminants, such as ink and binder, from the surface of fines and ash particles. The effects of CV-jet treatments for process water in deinking were investigated in terms of the number of dirt speckles, the effective residual ink concentration (ERIC) and the brightness of the treated samples.
  The results showed that CV-jet treatment decreased the average size of dirt speckles in the process water, and the treatment also facilitated ink detachment from the fines in the water. The number and average size of dirt speckles after CV-jet treatment were decreased by the subsequent flotation. And the degree of dirt reduction after CV-jet treatment was much higher than without the treatment. The brightness of the fines after CV-jet treatment was also improved by the subsequent flotation. Similarly, the brightness gain through the flotation after CV-jet treatment was much higher than without the treatment. These results indicated that CV-jet treatments improved the quality of the fines in the process water, which were difficult to be improved by conventional deinking devices. Therefore, the CV-jet technology has the potential to improve deinking process.