|Energy Saving by Remodeling
the Existing Boiler to the Gas Firing
Hokuetsu Paper Mills, Ltd.
In the Nagaoka Mill of Hokuetsu Paper Mills, Ltd. we have maintained
the mill, considering environmental protection (reducing CO2 etc.)
and energy-saving. Under the recent sudden rise in prices of oil,
further improvement in environmental protection, energy-saving and
reduction of energy costs has come to be urgent. We determined to
adapt our heavy oil boiler plant for natural gas that is supposed
to be the most effective way to solve the above problems. The remodeling
of all our existing boiler plants finished in November last year.
In this report, we introduce the point and the effect of the remodeling.
Black Liquor Evaporation to High Dry Solids with Crystallization
Evaporator Technology, Andritz Oy
Evaporation Technology, Andritz KK
Modern pulp mills have improved their energy efficiency by increasing
firing liquor dry solids concentrations. Steam production in a
recovery boiler can be increased over 2% when the firing liquor
dry solids content is increased from 75% to 80% /1/. At the same
time also SO2 emissions are practically eliminated.
When black liquor is evaporated to concentrations over 50-55%
sodium salts start to precipitate from the liquor. The precipitated
form crystals in the liquor and more or less scale on the evaporator
heating surfaces. Traditionally the scale is removed from the surfaces
by sequence switching technique, which may require water washing
The scaling formation on the heating surfaces can be reduced remarkably
by mixing electro static precipitator ash in the liquor before
high dry solids concentration. The ash particles act as centers
of crystallization (seeds / nuclei). The crystallization takes
place on the ash particles, not on the heating surfaces and the
need for the washings will be reduced remarkably.
This paper describes Andritz’s concept for high dry solids evaporation
with crystallization technology.
Steam Saving by Waste-Heat Recovery from Pulping Wastewater
Hachinohe Mill, Mitsubishi Paper Mills Limited
In Hachinohe mill of Mitsubishi Paper Mills Limited, an energy
saving is forwarded as an urgent task for a cost-reduction theme
which is set in "Pheonix Plan" of our company. An energy-utilization
committee and an executive meeting of international organization
for standardization (ISO) 14001 in our mill are organized with
same members to link efforts for the task. Thus, we are tackling
an improvement of a specific energy-consumption grasping an effect
of the energy saving in real time.
In this paper, effects of facilities, which started running in
November 2006 for a waste-heat recovery from wastewater, on the
energy saving were described. These efforts were conducted for
saving an increased steam usage in a papermaking process by decreased
water temperature in winter. Water temperature was increased in
the papermaking process by recovering waste-heat which had been
discharged to the atmosphere from a cooling tower of pulping wastewater.
This considerably improved a specific steam-consumption in the
Energy Saving Cases in Kraft Pulping Section
Pulping Section in Sendai Mill, Chuetsu Pulp & Paper Co., Ltd.
Recently, there has been an urgent need to reduce the cost in
pulp and paper mills, since the cost of raw materials and fuels
as raw wood and crude petroleum has risen. Energy consumption in
pulping section is high, then it leads to high production cost.
Its reduction even a little could contributes to company’s profits.
In this article, energy conservation which has been achieved by
optimizing the use of warm water, filtrate and operating condition
in the bleaching process, is reported.
Steam Turbine New Sealing and Clearance-controlling Technologies
Power Plant Service Center Power Systems Headquarters,
MITSUBISHI HEAVY INDUSTRIES, LTD.
In order to reply the recent growing needs for energy saving,
we focused the steam leak which is one of the most affective to
degradation of efficiency and developed and applied for new technology
to reduce leak loss.
Leaf seal is a new type of seal. It is different type from conventional
labyrinth seal. It has superior feature of good sealing and avoidance
of the heat by contact to the rotor. ACC (Active Clearance Control)
seal can change the clearance between during start & stop and
during load operation. It prevents contact during start & stop
and keeps smaller clearance in order to gain efficiency during
load operation. Cooling cell prevents contact between lower half
of the casing and the rotor by decreasing the differential temperature
between upper and lower half casing.
First we applied these new technologies to our in-house power
plant for verification. After confirmation of performance and reliability
for these new technologies, we applied them to commercial unit
without any problems.
We introduce these new sealing and clearance-controlling technologies.
Reduction of Heavy Oil Consumption in Lime Kiln
Oji Engineering Co., Ltd., Kushiro Dept.
Kushiro Mill produces 700 thousand tons per year of newsprint,
coated paper, mechanical paper and linerboard by four machines
with pulp plants (KP, RGP, DIP and OCC). Based on The Oji Paper
Group’s Environmental Charter, Kushiro mill has positively used
recycled resources for Product design and process of manufacture
with small environmental burden. Because of the increase in the
wastepaper utilization rate, Kraft pulp and The Black liquor production
decrease every year.
The Black liquor from KP plant is used Recovery Boiler for recollection
of heat and White liquor, so it is important to reduce the energy
cost in the mill.
Since the Black liquor has decreased, a process that produces White
liquor and Lime must been operated minimum rate.
In this report, I describe efficiency improvement of Lime Kiln to reduce Heavy
Saving Fuel Oil by Capacity Increase of No.4 Boiler
Nippon Daishowa Paperboard Tohoku Corporation
In accordance with our environmental policy; "Resources & Energy
Saving" and "Reducing & Recycling of Waste", we constructed
a Waste Heat Power Generation Plant (named No.4 Boiler) and started
commercial operation of the plant on October 2003.
The Plant runs on Paper Sludge and Waste Tire without auxiliary
fuel (i.e. fossil fuel) and generates high temperatures and pressures
steam stably with Waste Heat Boiler and generates 14,000 kW.
We have achieved certain reducing of fossil fuel consumption,
and we improved the plant for further resources saving. We increased
the steam generation capacity from 65 ton/h to 73 ton/h by adding
biomass fuel (i.e. wood chip) to cut tire and paper sludge. And
we started operation of the plant on February 2005. We successfully
could reduce the fuel consumption of No.2 Boiler by supplying the
increased steam of No.4 Boiler through the new process piping.
Now we will present an overview of construction work and operation
experience of the plant.
Case Studies of Collecting Our Waste-Heat at Mishima Mill, Daio
Mishima Mill, Daio Paper Corporation
The power generating facility at Misihima Mill has a 531 MW standard
output and consists of 18 boilers and 14 turbines. It supplies
all the electricity used by the facility and its surplus electricity
output is sold to the market.
After the oil crises of the 1970’s, Daio Paper shifted from a
dependence on petroleum towards coal. Since 1985 we have also attempted
increase energy production efficiency in the power plant by raising
the pressure and the temperature in the boilers and installing
new turbines. Additionally increased our production of recycled
pulp in the production process because it requires less energy
than wood chip processing. In 2005, we accomplished a 17% reduction
in fossil fuel energy consumption based on tonnage of output compared
We are trying to accomplish a 23% reduction by 2010 compared with
1990 levels in fossil fuel energy consumption based on tonnage
of output, a 20% reduction in carbon dioxide consumption.
Case studies of our energy curtailment efforts at Mishima Mill are discussed
in the following section
Power Consumption Reduction by Modifying Oil-outlet and Pressurizing
Shoe of CCR
Facility Department of Maintenance Section, Tomioka Mill, Oji Paper
CCR (Controlled Crown Roll) is one of important equipments to
get even dewatering in the cross machine direction.
It was developed jointly by Mitsubishi Heavy Industries, Ltd.
and Beloit Corp. over thirty years ago. And many CCRs are still
operation. But paper machine speeds has been increased 1.5 times
compared with the original design by a lot of rebuilds. Therefore,
many problems recently happen.
We will introduce some trouble cases maintenance engineers faces
on and solutions. And also, an example of save energy by modifications
of CCR on second press in Tomioka PM9 will be introduced, too.
Role and Effect of Ionic Groups of Polymer as a Surface Sizing
Paper Chemicals Division, Harima Chemicals, Inc.
In this paper, sizing behaviors of synthetic water-soluble polymer
surface sizing agents with different ionic charges were investigated
using bleached kraft pulp base papers prepared in various conditions.
The sizing efficiency of anionic surface sizing agent (A-SFS) was
proportional to the alum content in the base paper, and the addition
of CaCO3 to the base paper reduced its effect apparently. On the
other hand, it was found that the sizing behavior of cationic surface
sizing agent (C-SFS) depended on the presence of CaCO3. While the
sizing efficiency of C-SFS rose with the increase of alum content
in the base paper without CaCO3, that of C-SFS tended to drop with
the increase of alum content in the base paper with the addition
of either 10 or 20% CaCO3.
These results indicate that C-SFS develops surface sizing on papers
with more complicated mechanism than the case of A-SFS. Furthermore,
we suggest a novel mechanism of surface sizing by using various
analytical techniques as well.
Estimation of the Cost of Afforestation by the Cost Analysis
Tokiya Yaguchi, Takayuki Sato, Masato Takagi and Shigehiro Okamura
Research Planning Group
Research Institute of Innovative Technology for the Earth
In order to calculate the cost of carbon dioxide fixation by the large scale
afforestation (AF) for the reduction of the global greenhouse gas, we have analyzed
in detail about the one model AF data and 4 publication AF data. In this report,
we have defined the unit cost of accumulated (Acc) AF cost by US$/ha/year as
The unit cost of Acc AF cost by US$/ha/year
= The Acc AF cost by US$/the Acc area of AF by ha/year
As a result, we have obtained an estimated (Est.) cost of AF by US$/ha/year
with the functional formulas of the AF year (n) and the gross domestic product
capita (GDP/cap) of the AF country.
Est. cost of AF by US$/ha/year = 130 + 0.0341×n-0.445×GDP/cap (20≦n≦30)
There is a significant coefficient (R2 = 0.88) in 44 data between the real Acc
total cost of AF and the est. value.
By the same token, we have obtained Est. Cost of AF by US$/ha/year among 3 to
30 years of AF.
Est. Cost of AF by US$/ha/year = 800×n-0.566 + 0.141×n-0.879×GDP/cap (3≦n≦30)
In this case, there is a nearly equal coefficient (R2 = 0.90) in 157 data between
the real Acc. Total Cost of AF and the Est. Cost of AF.
Keywords: cost of afforestation, estimation, cost analysis, afforestation
years, gross domestic
product per capita
A Report on the 20th ISO/TC6 Meeting
Takayuki Okayama*1, Takashi Yaezawa*2, Shisei Goto*3 and Tadashi Kano*4
*1 Tokyo University of Agriculture and Technology
*2 Oji Paper Co., Ltd.
*3 Nippon Paper Industries Co., Ltd.
*4 Japan Technical Association of the Pulp and Paper Industry
ISO/TC6 meeting was held on November 13-17, 2006 in Atlanta, USA. The number
of registered delegates representing seventeen countries was seventy three.
Four delegates representing Japan attended WG meetings, plenary meetings of
and SC5, and TC6 plenary meeting.
Development of Method for Analyzing Internal Properties of Coated Paper: Image
Analysis Using X-ray Microtomography
Nippon Paper Industries Co., Ltd.
Cyrus K. Aidun
G. W. Woodruff School of Mechanical Engineering
Georgia Institute of Technology
This paper reports a technique, based on analysis of X-ray micro-tomography
images to analyze the internal properties of coated paper through the thickness
direction (ZD). The image analysis method for paper applications using μCT have
been developed by a few groups, but the method that can analyze these images
to obtain the full range of properties in detail has not been presented before.
The internal properties include formation and fiber orientation distribution
through the thickness direction (ZD), as well as ash and pore distribution in
x-y- and z-directions. The image analysis technique involved many steps including
axial conversion, filtering, binarization, skeletonization and alignment. The
method is applied for analysis of two kinds of coated paper and the results provide
interesting insight for papermaking.
Keywords: X-ray tomography, ash, formation, fiber orientation, distribution,