Paper quality
at Dryer section
Takashi Nagaoka
Paper & Printing Machinery Division, Mitsubishi Heavy Industries,
Ltd.
Dryer section has been composed of multi cylinder dryers and steam
heat has been used for drying from old time. On the point of view
from paper quality, the moisture profiles at thickness direction
and cross machine direction especially influence the quality in
dryer section.
In this paper, the development of dryer section, the trend of
paper market, the required paper quality from the printing machine,
the
paper quality improvement by dryer section are introduced.
Latest Technology of Dryer Section
- Introduction of Voith HiDryer -
Osamu Yasui
Voith IHI Paper Technology Co., Ltd., Application Engineering Dept.
During the last few years the paper machines around the world
set one speed record after another. Today the speed limit of
paper machine is defined by the strength of the wet sheet in
the beginning area of the dryer section. Even in the single-tier
dryer with modern stabilizer “ProRelease”, the considerable web
tension is required for the better operation. So the solution
for further paper machine speed-up is simply the dryness increasing
before the conventional dryer section once more.
The perfect solution comes with the development of Voith HiDryer
with impingement drying system. Here we introduce this sophisticated
new drying equipment for successful future.
The Latest Technology of Dryer Hood and Machine Room Ventilation
Kouji Saito
Metso SHI Co., Ltd., Application Engineering
Dryer section hood and ventilation system has been developed
together with the development of paper machine production. Flow
volume of exhaust air from the latest dryer hood and ventilation
system has been minimized by adopting high humidity in the exhaust,
which has minimized the energy loss from the exhaust air by increasing
the heat recovery efficiency as warm water and pre-heating of
hood supply air. However, minimized exhaust air volume does not
prevent evaporation from the paper by supplying sufficient amount
of heated dry air to the pocket; in addition it improves web
runnability by newly developed blow boxes. Modern air system
consists of hood and ventilation mentioned above, air dryer system
in the coater dryer, mist ventilation in the wet end and machine
hall ventilation.
The latest system of dryer hood with it’s history, heat recovery,
mist ventilation and machine hall ventilation are introduced
in this paper.
The Improvement of PM9 Production Efficiency by Retrofitting
the Dryer Section at Shiraoi Mill
Yuji Hoshino
Shiraoi Mill, Nippon Paper Industries Co., Ltd.
No.9 paper machine at Shiraoi mill, Nippon Paper Industries,
has been in operation as fine paper machine since 1975.
In 1995, it was remodeled for coatbase paper machine. We had
difficulty problems result of increasing the machine speeds,
and the modification of paper grades.
One problem was the sheet breaks caused by sheet flutters, and
other was the sheet spots caused by dewdrops. In November 2004,
we improved these problems with replacement of pocket ventilation
systems.
In this report, I introduce this replacement and the operating
experience.
Basis Concept of Drainage Equipment
Yoshiyuki Gohoh
M･S Netsugakukogyo Co., Ltd.
Dryness of Wet paper is an action that evaporates the moisture
by heat, and is movement of heat and a substance. As for the
basic concept of Drainage equipment, for these what ten years
is not changing. In Drainage equipment, in connection with the
M/C speed rise of a Paper machine, condensate water discharge
apparatus evolved into high speed stationery siphon + blow through
steam from bucket + steam trap.
A regulation meter and control apparatus have also changed from panel board
of
an air formula to an electronic formula regulation meter or DCS. By this sentence,
Drainage Maker plans to introduce the actual condition of the Drainage equipment
design business centering on the heat calculation to some extent.
Technical Trends in Dryer Fabrics
Hideyuki Onishi
Shikishima Canvas Co., Ltd.
Dryer fabrics, which are used on many parts of dryer sections
of paper making machines, have longer longevity than other paper
making clothing like forming fabircs and press fabircs. For this
reason, they are necessarily required to be maintained good and
stable condition for fairly long periods.
To enable dryer fabrics to be used for longer periods on the
paper making machines in Japan, which have been controlled by
the highest standards of management and control system achieved
by the Japanese paper making manufacturers, it will be very important
and indispensable for dryer fabric manufacturers to continuously
make every efforts in improving and developing the quality of
dryer fabrics.
In this discourse, the new technology incorporated in improving
and developing dryer fabrics will be reported with specific examples
based on following themes:
The improvement on durability of dryer fabrics
The countermeasures for anti-contamination of dryer fabrics
The dryer fabrics for high speed paper making machines
Besides above, “The understanding on the present state of dryer
sections” will be also reported, which we learned through our
various measurments on site.
High Pressure Waterjet Canvas Cleaning Technology
Makoto Matsushita
KGK Engineering Corp., NUSM Division
We started selling the High Pressure Water Jet Canvas Continuous
Cleaning System presented by ProJet B.V., Meerssen, Holland,
April 2004, and delivered the first system in September the same
year. Ever since over less than one year, we sold total 15 systems
and are enjoying ever ceasing sales and new inquiries. Over our
sales activities as above, we have heard many cases in the past
over the competitors’ systems that they did not bring about satisfactory
cleaning results as was expected of.
What secrets there are in the ProJet system that have resulted
in such a remarkable surge in the sales over less than one year
period? What are differences between ProJet system and others?
Where we are planning to go to improve ProJet system further?
We are going to talk and introduce about those topics in this
workshop.
Solutions for Deposit on 1st Drying Part of PM１at Oita Mill
Katsuyuki Ohkawa
Oita Mill, Oji Paperboard Co., Ltd.
In Oita Mill , we started up the PM1 in May 1970 , which at
the time had Inverform machine. Originally the machine had four
inlets
which had a wire width of 4200mm , and produced 300T/D linerboard.
Since then, the PM1 was rebuilt for the purpose of improving
product quality and increasing machine speed.
Presently we produce 600T/D of kraft pulp liner on average,
with a maximum operation speed of 900m/min. But we had some trouble
for deposit on drying part all the time. In October 2004 we remodeled
the canvas cleaner on 1st drying part. Combi Cleaner, the name
of the canvas cleaner, carries professional high pressure water
jet.
The following report describes the operational experience of
the Combi Cleaner from initial start up to the present time.
A Report on the 19th ISO/TC6 Meeting
Takayuki Okayama*1, Takashi Yaezawa*2 and Tadashi Kano*3
Pulp and Paper Testing Committee, JAPAN TAPPI
*1 Tokyo University of Agriculture and Technology
*2 Oji Paper Co., Ltd.
*3 Japan Technical Association of the Pulp and Paper Industry
ISO/TC6 meeting was held on June 6-10, 2005 in Stockholm, Sweden.
The number of registered delegates representing seventeen countries
was eighty three.
Three delegates representing Japan attended WG meetings, plenary
meetings of SC2 and SC5, and TC6 plenary meeting.
Physical Structure Characterization of High Viscosity Kenaf Bast
Pulps
Sherif Keshk
Ain Shams University, Institute of Environmental Studies and
Research (Egypt)
Wiwin Suwinarti and Kazuhiko Sameshima
Kochi University, Faculty of Agriculture
The high viscosity kenaf bast pulps were prepared by using three
different methods (A, B and C) and their viscosity values were
109, 63 and 102 cP, respectively. The physical structures of
these samples were characterized by FT-IR spectroscopy, X-ray
diffractmetry and CP/MAS 13C NMR spectroscopy. Although the FT-IR
spectra of all pulp samples revealed the similar chain conformation,
the magnitude order of mean hydrogen bonding, relative ether
linkage and crystallinity index were in the same trend with the
order of viscosity values. X ray diffractograms and CP/MAS 13C
NMR spectra indicated the presence of residual lignin between
the (1 10) plane of the pulp that subjected to the method B.
However, FT-IR, X-ray and CP/MAS 13C NMR analyses showed the
method A gives the highest crystallinity pulp.
Furthermore, the relationships between the viscosity and the crystallinity index
values in these three methods were in a high correlation (R>0.9), that indicates
the viscosity is parallel to the crsytallinity.
Keywords: CP/MAS 13C NMR spectroscopy, crsytallinity index, FT-IR spectroscopy,
kenaf bast fiber, viscosity, X-ray diffractmetry.
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