2006年5月 紙パ技協誌

An Inside Power-plant for the Purpose of Saving Energy and CO2 Reduction

Shigeaki Obayashi
The First Energy Service Company, Limited

 The Kyoto Protocol, an international and legally binding agreement on gases emissions has entered into force on 16 February 2005. To meet this protocol, Japan has to step up in a new phase for CO2 reduction. On the other hand, the law of saving energy, which was established by METI (Ministry of Economy, Trade and Industry), has been revised several times in order to tighten up the original. So the private sector has been requested more efforts for saving energy.
 Recently, crude-oil price has risen more than twice as compared with that of two years ago, and also has set the record of 70 US dollars per barrel last summer. Under these circumstances, it is seriously required an introduction of more effective plant system or less fuel consumption plant.
 In this paper, we explain the recent engine for the power generation in the use of an inside power plant, and aim to give some suggestions for saving energy, reducing CO2 and also saving cost. Also we briefly explain the ESCO (Energy Service COmpany) which is recently adopted in many companies as a way of introducing plant system for saving energy.

Energy Saving by Introduction of the Gas Turbine Cogeneration System

Hiroshi Nagata
Kanzaki Mill, Oji Paper Co., Ltd.

 Located in the city of Amagasaki, Hyogo Prefecture, where the Kanzaki river a tributary stream of the Yodo river, the source of which is Lake Biwa-flows into the Osaka bay, the Kanzaki mill is an urban-style mill in the Kei-han-shin metropolitan area. The mill has 25 million population in its background. The mill started the production of coated paper in 1922. The coating technology has been handed down to us through the mill’s long history. Since then, it has undergone various changes, the mill is well known as a mill manufacturing various processed paper by the communication paper.
 Here, in Amagasaki, as same as in other industrial arrears in Japan, we must positively make efforts to solve the problems in order to meet more severe environmental standards on air and water pollution, legislated by Amagasaki city and Hyogo prefecture.
 Since the mill introduced gas turbine cogeneration system instead of conventional and gas boiler and steam turbine generating system in September 2003, we introduce the way and result of energy saving by taking this system as a case.

Energy Saving in the Bleaching Plant
- Steam Saving Examples by Raising the Temperature of Hot Water -

Tomomi Inaba
Nippon Daishowa Paperboard Yoshinaga Co., Ltd.

 Nippon Daishowa Paperboard Yoshinaga Co., Ltd. has been trying to expand the use of recycled paper with taking advantage of a good location near the Tokyo metropolitan area.
 New No.5 incinerator has been operated from December 2002 for the purpose of incinerating paper sludge and generating power for mills facilities. But a consumption of fuel oil has been continued at a high level, then we have lost significant earnings as a result of a sharp oil price increase in recent years, we have felt a strong need for energy saving.
 No.1 bleaching plant is located apart from the cooking plant and the chemical recovery plant, so it can not use the heat from black liquor. For the reason, it consumes the large amounts of steam.
 This report describes steam saving examples by raising the temperature of hot water with using the heat of absorbent in No.5 incinerator desulfurization equipment.

Energy Saving with ID-Screen

Hirotada Tsukakoshi
Nayoro Mill, Oji Paperboard Co., Ltd.

 We have pulper, screen, a process of refiner in raw materials process producing wastepulp from wastepaper as facilities using particularly big energy.
 In paper manufacture industry of energy many consumption model, it is a point to be connected directly with cost reduction to promote energy saving positively.
 I introduce ID technology of Aikawa Iron Works Co., Ltd. into existing screen this time and I remodel it into dilution white water injection model screen (ID screen) and introduce the example that wrestled to power-saving

CO2 Reduction by Remodeling the Existing Boiler to the Gas Firing

Takao Koide
Power Plant Service Center, Mitsubishi Heavy Industries Limited

 KYOTO protocol has taken effect since February 2005 and Japanese government requests industries to reduce 8.6% of CO2 emission in 2010 compare to 1990 as the aim. Addition to that, fuel oil price is getting higher recently, because of high crude oil price.
 As a result, the company which has oil firing boiler has to study the reduction of CO2 emission and fuel oil cost for boilers.
 Therefore, MHI suggests the remodeling the oil firing boiler to the gas firing for the reduction of CO2 emission and fuel oil cost simultaneously.
 In this thesis, general and example of gas firing modification are introduced. And also, finance lease of sate light base for gas supply instead of gas pipe line, which MHI will provide, is introduced.

Energy Saving by Installation of Boiler Exhaust Gas Heat Recovery System

Satoshi Takai
Nomachi Mill, Chuetsu Pulp & Paper Co., Ltd.

 In late year, as the issues concerning Environment and Energy are taken close-up globally, the measures to meet them became the urgent business. Then so-called Kyoto Protocol was taken effect as an anti-global warming measure in February, 2005. Reduction of the carbon dioxide discharge was fixed against Japan based on it. Japan Paper Association fixed the following target as a voluntary action plan.
1) Reduce the fossil energy consumption per ton of paper by 13% until 2010 compare with the
  1990 level
2) Reduce the carbon dioxide discharge per ton of paper by 10% until 2010 compare with the
  1990 level
 On the basis of such a world trend, we in Nomachi Mill are wrestling with deducing the environmental load, with promoting the energy saving and the effective use of waste paper and wood resources. In Nomachi Mill, as a part of long term energy saving, we installed Boiler Exhaust Gas Heat Recovery System in the effluent gas chimney flue of the No.3 Recovery Boiler in July 2005 and decided to utilize the waste heat for warming the feed water of the above mentioned boiler. I want to introduce the example as follows.

A Reduction Approach to CO2 Emissions by Introducing a Large-scale Recovery Boiler

Shigeru Wakamoto
Niigata Mill, Hokuetsu Paper Mills, Ltd.

 The approach of measures for controlling global warming and energy conservation has became important more and more by coming into effect the Kyoto Protocol in February, 2005. Additionally, conserving energy has been getting important as a measures of recent sudden rise of crude petroleum. Hokuetsu Paper, Niigata Mill introduced a large-scale recovery boiler in April, 2005 to replace the superannuated boiler, decrease the air pollutant, etc. Therefore, the plan of both air pollutant reduction and energy conservation were started by considering the best operating combinations of the new boiler and the existing boiler. In this report, the approaches of energy conservation and the CO2 reduction are described after introducing outline of the large-scale recovery boiler.

Water Jet Turning-Up System

Makoto Matsushita
KGK Engineering Corp., NUSM Division

 Paper mills have been long after the turn-up efficiency improvement and subsequent paper loss reduction. Our full automatic “ReelJet” turn-up system (Paprima Industries Inc., Montreal, Canada) uses 2 units of ultra high pressure water-jet cutting head (1300-1500bars/20cc per turn-up) which run fast (2m/sec) to their waiting position each side of the line to get the sheet expanded to its full width keeping a completely uniformed wrapping both ways from the center, immediately after the tail has got caught by a new spool with the help of an air-coanda effect of a specially designed gooseneck. Thus, “Reel Jet” makes it possible to execute turn-ups failure free in such a shorter time span as 2 seconds since the issue of turn-up command via DCS until the two heads come back to their park-positions. Also, its beautifully balanced and even wrapping on a spool can release the reel part from vibration and noise related problems.
 Its sales has been expanding among big scale world famous paper machines in Europe and North America, and they are quite satisfied with its overwhelmingly nice performance to cut paper loss and subsequently to improve productivity remarkably. Hereunder, we are going to explain about its structure and performance.

Solutions for High Quality Tissue Creping

Yoshinori Sekiyama
Sales Engineering Dev., Maintech Co., Ltd.

 The Yankee dryer is a critical part of the tissue making process and its surface plays an important roll in achieving good sheet quality. Therefore, it is imperative that the Yankee surface is well protected. Maintech has developed “Ultra Lubrication Creping” an innovative and unique method in which Yankee dryer is protected by a lubrication coating layer composed of resin and disulfide molybdenum. The resulting surface reduces the friction between the dryer and doctor blade and extends the life of doctor blade dramatically.
 Also, felt filling due to pitch and/or stickies can lead to any number of problems, including unstable coating layer, poor sheet quality, lost production, unscheduled shutdowns, and increased operating costs. Maintech has developed a series of deposit control products “MainteClean” whose amphoteric polymer prevents the pitch and/or stickies from accumulating on the felt and felt rolls. The treated felt gives positive impacts not only on the felt condition but also on the dryer coating.
 This paper reviews the innovative methods of Yankee coating and felt conditioning comparing with conventional methods. Case histories illustrating gained benefits in tissue grade M/C are presented.

Low Consistency Refining Technology
LemaxX Spiral - Nature Applied

Kenichi Ito
Andritz k.k., Japan
Peter Antensteiner
Durametal Corporation

 Andritz is a leading supplier of refining technology in the world. Also Andritz supply wear materials for refining process. Durametal Corporation, a subsidiary of Andritz, produces the refiner plates. This company has over 8,000 patterns of refiner plates and several new patterns developing in a week. Also Durametal plans to develop a simulation program “MAGNUS”, it is simulate the “Nature of Refining” theory. Using this program Durametal Corporation developed The Logarithmic Spiral Design refiner plate LemaxX Spiral.
 This report introduces the performance of LemaxX Spiral technology.

Wastewater Treatment in Japanese Pulp and Paper Mills Today

Environmental Technical - Committee of Japan Tappi
Environmental Protection Committee, Japan Paper Association

 This survey of wastewater treatment in the Japanese pulp and paper industry is based on operations of 102 mills in 2002. Data covered 98% of pulp production (except recycled pulp including deinked pulp, DIP) and 89% of the production of paper and board products, and was compared with the last survey’s in 1991.
 As the Japanese economy had been sluggish in this 11 years, pulp production in 2002 decreased by 9% and paper and board production was confined to 10% increase. One third of the mills each produced annually over 0.3million tonnes of market products. 72% of the mills produced both pulp and paper products. 31% of the mills had kraft pulping process. Half of the mills discharged effluents into rivers and 41% into seas. Enclosed coastal seas (Tokyo Bay, Ise Bay and Seto Inland Sea) received effluents from 30% of the mills.
 Enhanced awareness of the environmental preservation in Japan has further strengthened the effluent limitations. Discharge limits of suspended solids (SS) and biological oxygen demand (BOD5) were lowered by an average of 20% and chemical oxygen demand (CODMn) by 10%.
 As the results of sustained effort of the Japanese pulp and paper industry, the average specific discharge of SS in 2002 has decreased to 2.6 kg per ton of market products, BOD to 2.8 kg/t , COD to 7.4 kg/t, and the average specific consumption of water has been lowered to 88 m3 /t , which corresponded to a reduction of 29% on SS, 42% on BOD, 30% on COD and 16% on water consumption.
 Though coagulation-sedimentation was still the mainstream of wastewater treatment, the multistage processing including some biological treatments has spread progressively. Many activated sludge plants have shifted their aeration gas from air to oxygen, and then more than 50% of BOD and COD loads in wastewater have been removed by the activated sludge process.
 The average operational staff of wastewater treatment was 4.7, decreased to one third from 1991.

International Conference Report
― The 5th Biennial Johan Gullichsen Colloquium, Finland ―

Toshiharu Enomae
Graduate School of Agricultural and Life Sciences, The University of Tokyo

 On November 17th, 2005, the 5th Biennial Johan Gullichsen Colloquium was held in Helsinki, Finland. This colloquium was initiated by Professor (currently emeritus) Johan Gullichsen of Helsinki University of Technology in order to encourage especially young engineers and scientists. The 5th colloquium featured “Raw materials and processes ― viewpoint of product” and covered a wide range of topics including 5 categories and 8 aural presentations from all over the world. The summary of those presentations are reported.

Report of Studying at University of Maine

Kenji Hirai
Research and Development Dept., Product Development Research Lab.
Nippon Paper Industries Co., Ltd.

 The author had an opportunity to study at University of Maine for one academic year of 2004. The author has belonged to Paper Surface Science Program (PSSP) in chemical engineering department of University of Maine as a visiting scientist. In this report, mission and current research activities of PSSP, the impression of the studying and the life at University of Maine are reviewed.

Keywords: University of Maine, Paper Surface Science Program, PSSP, Visiting scientist

Reduction of AOX by Prolonged ClO2 Bleaching under High Temperature and Acidic pH Conditions

Kengo Magara, Tsutomu Ikeda, Tomoko Sugimoto and Shuji Hosoya
Department of Chemical Utilization, Forestry and Forest Products Research Institute

 Decreases in AOX during chlorine dioxide bleaching at high temperatures and under acidic conditions were investigated. When the temperature in the chlorine dioxide bleaching stage was raised from 70oC to 95oC, a certain decrease in AOX was detected. AOX is formed by a chlorine substitution reaction with mainly lignin and chlorine that was generated from a reduction of chlorine dioxide. For the chlorination of lignin, it appears that raising the temperature facilitated an oxidation reaction rather than a substitution reaction, so that the rapid consumption of chlorine in the oxidation reaction suppressed the substitution reaction.
 Extension of the bleaching period from 15 min to 90 min also decreased AOX discharge. In the first chlorine dioxide stage in bleaching, high temperature and acidic pH were employed to hydrolyze hexeneuronic acid as well as remove lignin. In this bleaching condition, some of the lignin was also subjected to hydrolysis. However, the cause of a dehalogenation reaction that was required to decrease AOX is difficult to understand. To determine the cause of dehalogenation, some chlorinated compounds such as a chlorinated aromatic compound and a chlorinated organic acid were heated at 95oC for 90 -120 min under acidic conditions. However, no explanation could be found to account for the decrease in AOX. Therefore, further investigation should be conducted to determine why the AOX reduction was induced by prolonging the bleaching period.

Keywords: chlorine dioxide bleaching, AOX, high temperature, acidic pH, bleaching period