kajaani
Metso Automation Field Systems Division Kehräämöntie 3 , P.O. Box 177 FIN-87101 Kajaani Finland Tel. +358 20 483 120 Fax +358 20 483 121
North America 3100 Medlock Bridge Road, Suite 250 Norcross, GA 30071 USA Tel. +1 770 446 7818 Fax +1 770 242 8386 Latin America Av. Central 181, Chácaras Reunidas 12238-430 São José dos Campos SP Brazil Tel. +55 12 3935 3500 Fax +55 12 3935 3535 Asia Pacific 501 Orchard Road #05-09 Wheelock Place 238880 Singapore Tel. +65 673 552 00 Fax +65 673 529 55 www.metsoautomation.com
B48 42.1_EN © Metso Automation, 8/2002 Printed on recycled paper manufactured from 100% post consumer waste.
Europe Levytie 6 , P.O. Box 310 FIN-00811 Helsinki Finland Tel. +358 20 483 150 Fax +358 20 483 151
Recycled Fiber Management The Key To Better Paper Quality
PulpExpert measures automatically: • Consistency • Brightness, color, light scattering • Dirt count • ERIC • Fiber length • Tensile • Freeness from up to 8 sampling points
The Key To Better Paper Quality From Recycled Fiber
Ash
ultimate confirmation of pulp quality based
The ash content of the process is indicative
on laboratory standards; brightness, ERIC,
of the quality and ratio of the raw materials
dirt count, light scattering and color
used, and the operation of flotation,
from its automatically prepared and
screening and cleaning. The kajaaniRMi
measured hand sheets.
provides accurate and continuous
PulpExpert measures the size, shape and
measurement of ash content in addition to
contrast of each individual dirt spec in the sample and classifies the results in userselectable classes.
kajaaniCORMECi Brightness and ERIC measurements
Improvements in process stability, better
Consistency
control of the mechanical and chemical
In many cases, total consistency is the single
processing and effective control of the raw
most important measurement in the entire
consistency so that the operator can easily
material components all provide
line. As an example, total Cs of the first
find the right set points for process
tremendous economic benefits. The result
flotation stage is of crucial importance, and
parameters.
is lower chemical and energy consumption,
the effect of any consistency variation at
better machine runnability and improved
this point will be seen in all subsequent
end product quality. In recycled fiber
stages, possibly even amplified. Metso has
Brightness, residual ink and dirt
production, key measurements include
mechanical, optical and microwave
The brightness of recycled pulp is
Recycled fiber, or waste paper, is
consistency, ash, brightness, residual ink,
transmitters, each optimized for recycled
dependent on lignin content, ink and dye
increasingly being used as a raw material
dirt count, pulp quality and chemical
fiber applications that together with the
concentration as well as ash and other non-
of papermaking processes, even for many
properties. The relative importance of each
PulpExpert absolute consistency
fiber constituents. The kajaaniCORMECi can
"new" paper and board grades. Newly
measurement depends on the process and
measurement provide continuous and
continuously measure in-line the separate
developed measurement technology and
on the end use of the pulp.
accurate information.
process control can have a great impact on the quality of the finished product.
effects of lignin, ink (Effective Residual Ink kajaaniRMi
Concentration) and dye. The PulpExpert
kajaaniMCAi
Ash content measurement
analyzer with online sampling provides
Microwave consistency transmitter
PulpExpert measures automatically: • Consistency • Brightness, color, light scattering • Dirt count • ERIC • Fiber length • Tensile • Freeness from up to 8 sampling points
The Key To Better Paper Quality From Recycled Fiber
Ash
ultimate confirmation of pulp quality based
The ash content of the process is indicative
on laboratory standards; brightness, ERIC,
of the quality and ratio of the raw materials
dirt count, light scattering and color
used, and the operation of flotation,
from its automatically prepared and
screening and cleaning. The kajaaniRMi
measured hand sheets.
provides accurate and continuous
PulpExpert measures the size, shape and
measurement of ash content in addition to
contrast of each individual dirt spec in the sample and classifies the results in userselectable classes.
kajaaniCORMECi Brightness and ERIC measurements
Improvements in process stability, better
Consistency
control of the mechanical and chemical
In many cases, total consistency is the single
processing and effective control of the raw
most important measurement in the entire
consistency so that the operator can easily
material components all provide
line. As an example, total Cs of the first
find the right set points for process
tremendous economic benefits. The result
flotation stage is of crucial importance, and
parameters.
is lower chemical and energy consumption,
the effect of any consistency variation at
better machine runnability and improved
this point will be seen in all subsequent
end product quality. In recycled fiber
stages, possibly even amplified. Metso has
Brightness, residual ink and dirt
production, key measurements include
mechanical, optical and microwave
The brightness of recycled pulp is
Recycled fiber, or waste paper, is
consistency, ash, brightness, residual ink,
transmitters, each optimized for recycled
dependent on lignin content, ink and dye
increasingly being used as a raw material
dirt count, pulp quality and chemical
fiber applications that together with the
concentration as well as ash and other non-
of papermaking processes, even for many
properties. The relative importance of each
PulpExpert absolute consistency
fiber constituents. The kajaaniCORMECi can
"new" paper and board grades. Newly
measurement depends on the process and
measurement provide continuous and
continuously measure in-line the separate
developed measurement technology and
on the end use of the pulp.
accurate information.
process control can have a great impact on the quality of the finished product.
effects of lignin, ink (Effective Residual Ink kajaaniRMi
Concentration) and dye. The PulpExpert
kajaaniMCAi
Ash content measurement
analyzer with online sampling provides
Microwave consistency transmitter
1 Pulping
Removing ink and dirt. Achieving quality targets. Step by step,
Pulping is the first critical step in recycling and deinking. It determines how well the fibers are separated from each other, which has a subsequent impact on yield. If contaminants are not well enough separated from the fiber, removing them will increase fiber losses. On the other hand, severe pulping conditions may reduce the size of contaminant particles and thus complicate their subsequent removal from the pulp. Ink separation from fiber is primarily
4
accomplished in the pulper, and the ease of ink removal in the first deinking stage is mainly determined by the pulping conditions. Consistency at the pulper outlet is one of the most important control parameters which influences the operation of the entire deinking plant. The kajaaniMCAi flow-through consistency transmitter, based on microwave technology, is independent of pulp type making it ideal for
3
recycled applications. Chemical addition to the pulper can be controlled by measuring peroxide residual with kajaaniPOLAROXi in the recirculation water and controlling caustic addition for maximum effect.
2
2 Coarse and Pre-screening Coarse screening removes large foreign items from the pulp.
8
1
Screening and cleaning are important steps, as these remove most the remaining non-fibrous contaminants including stickies. In the early stages of the process there is still quite an amount of unwanted material present, and the flow-
7
through kajaaniMCAi is the best solution for consistency measurement. Brightness measured here or even earlier after the pulper gives an idea of what to expect after deinking and can help by optimising raw material usage when higher brightness waste paper is available.
3 Flotation The kajaaniCORMECi brightness transmitter can, by using different wavelengths, be used to separately resolve the influences of lignin, ink and dye. By measuring the Effective Residual Ink Concentration (ERIC), the degree of success of ink removal can be determined and adjustments made for
5 6
better efficiency. This will include chemical dosages to the pulper and flotation as well as optimizing conditions in subsequent cleaning and screening operations. Consistency should be controlled at the inlet of the flotation cell, to stabilise pulp quality and to ensure stable process operation. Consistency and ash content measured with kajaaniRMi at the inlet and outlet of the flotation cell indicate filler losses inside the cell. Ash content can be optimised in two alternative ways. For some paper grades no ash is accepted, while for others, fillers in the deinked pulp should be retained as long as the ratio can be kept constant.
RCF Process Measurements
1 Pulping
Removing ink and dirt. Achieving quality targets. Step by step,
Pulping is the first critical step in recycling and deinking. It determines how well the fibers are separated from each other, which has a subsequent impact on yield. If contaminants are not well enough separated from the fiber, removing them will increase fiber losses. On the other hand, severe pulping conditions may reduce the size of contaminant particles and thus complicate their subsequent removal from the pulp. Ink separation from fiber is primarily
4
accomplished in the pulper, and the ease of ink removal in the first deinking stage is mainly determined by the pulping conditions. Consistency at the pulper outlet is one of the most important control parameters which influences the operation of the entire deinking plant. The kajaaniMCAi flow-through consistency transmitter, based on microwave technology, is independent of pulp type making it ideal for
3
recycled applications. Chemical addition to the pulper can be controlled by measuring peroxide residual with kajaaniPOLAROXi in the recirculation water and controlling caustic addition for maximum effect.
2
2 Coarse and Pre-screening Coarse screening removes large foreign items from the pulp.
8
1
Screening and cleaning are important steps, as these remove most the remaining non-fibrous contaminants including stickies. In the early stages of the process there is still quite an amount of unwanted material present, and the flow-
7
through kajaaniMCAi is the best solution for consistency measurement. Brightness measured here or even earlier after the pulper gives an idea of what to expect after deinking and can help by optimising raw material usage when higher brightness waste paper is available.
3 Flotation The kajaaniCORMECi brightness transmitter can, by using different wavelengths, be used to separately resolve the influences of lignin, ink and dye. By measuring the Effective Residual Ink Concentration (ERIC), the degree of success of ink removal can be determined and adjustments made for
5 6
better efficiency. This will include chemical dosages to the pulper and flotation as well as optimizing conditions in subsequent cleaning and screening operations. Consistency should be controlled at the inlet of the flotation cell, to stabilise pulp quality and to ensure stable process operation. Consistency and ash content measured with kajaaniRMi at the inlet and outlet of the flotation cell indicate filler losses inside the cell. Ash content can be optimised in two alternative ways. For some paper grades no ash is accepted, while for others, fillers in the deinked pulp should be retained as long as the ratio can be kept constant.
RCF Process Measurements
Brightness Loss Caused by Ink in Pulp
Process Variables in Deinking
The Effect of Ink at Different Wavelengths
Comparison of Lab Results and kajaaniCORMECi Reading
0.18 Ash Cs, % (inlet of 2nd flotation stage)
0.14 0.1 0.06 0
5
10
15
20
Time, hours
0
5
10
15
20
Time, hours
70 Level of 2nd flotation stage
69 68
65
100 ppm increase in ERIC will decrease pulp brightness by about 2.5 ISO
Brightness (deinked pulp to PM)
60
The ink has strong absorption at wavelengths over 700
55 50
(e.g. from 62 to 59.5%). To counter this brightness loss with bleaching
Laboratory residual ink content (ERIC) vs. inline sensor ERIC measurement.
nm and causes a drop in reflectance index. The effective 0
5
10
15
20
Time, hours
we should increase fiber brightness from 62 to 68%. Brightness increase
residual ink test method, ERIC, is based on the absorption of infrared light.
with DIP is roughly only 50% of the increase which we can achieve with
Normal process variation in flotation. Ash consistency
virgin pulp in bleaching.
measured in inlet and Brightness measured on outlet.
7 Before Pulp Storage Prior to pulp storage, brightness, residual
Measurements to the paper machine serve
Optimized Solutions for Your Process
ink, and dirt count will provide valuable
as the final quality assurance and in some
We hope that this process description has
information on quality to the paper
mills can be used for blending operations
served as an introduction to the possibilities
6 Dispersion and Post Flotation
machine. Overall trends can be identified
before the paper machine to achieve
of good RCF measurements that will
quickly and adjustments made to the
required strength or brightness targets.
provide the desired final product quality at
Brightness, residual ink and dirt count can
process. In extreme cases, decisions to
be measured with PulpExpert. Conditions
recirculate out of specification pulp or treat
Brightness Monitoring in DIP Process
environmental impact. There are many
should be controlled to achieve the
it differently can be made with confidence
with the Inline Brightness Sensor
modifications, differences and
maximum dispersed ink removal.
before it contaminates the storage tower.
improvements that can be made to the
Additionally kajaaniCORMECi can also be
As well as deinked pulp brightness and dirt
example process we have used. Please
used for a continuous brightness and ink
count, PulpExpert can measure other pulp
contact your local Metso Automation
paper product is below 60 – 65% ISO,
content monitoring to control these final
properties such as strength and color. If a
resource to find the optimum configuration
adding peroxide into the pulper is often
deinking steps. Ash content is very
final reductive bleaching stage is in use,
for your process as well as the insight we
enough. For higher brightness multistage
important as minimal variation is needed
kajaaniCORMECi can provide slow feedback
have gained in other applications.
bleaching is needed, including both
to ensure good runnability on the paper
correction to the hydrosulfite stage control
Feed consistency to screening is important
oxidative and reductive bleaching
machine.
with the continuous brightness, residual
to ensure the maximum removal of
chemicals. Brightness and residual ink can
contaminants including dissolved solids
be measured on-line using the
and remaining stickies. Consistency control
kajaaniCORMECi brightness transmitter and
SmartPulp Valmet
is normally done in two stages using
used for a feedforward control strategy. The
blade consistency
SmartPulp consistency transmitters with
brightness loss caused by ink in pulp is hard
transmitter
blades specially designed for this
to counter by bleaching alone because the
application. In addition to dirt count,
pulp brightness has to be much higher to
PulpExpert's absolute consistency
counteract optical properties of the residual
measurement can provide continuous
ink. Stable pulp brightness after the
tuning for superior accuracy even with
bleaching tower is thus very difficult to
varying pulp components.
achieve if the ink content varies a lot.
5 Bleaching If the brightness requirement for the final
4 Cleaning and Fine Screening
ink and L-a-b color measurements.
8 Final Quality
the most economical level while minimizing
Pulp brightness at different stages of DIP process; 1. After first flotation, 2. After second flotation and 3. After hydrosulphite bleaching – final brightness. 10 % more magazine paper in the raw material means 1 % higher brightness.
Brightness Loss Caused by Ink in Pulp
Process Variables in Deinking
The Effect of Ink at Different Wavelengths
Comparison of Lab Results and kajaaniCORMECi Reading
0.18 Ash Cs, % (inlet of 2nd flotation stage)
0.14 0.1 0.06 0
5
10
15
20
Time, hours
0
5
10
15
20
Time, hours
70 Level of 2nd flotation stage
69 68
65
100 ppm increase in ERIC will decrease pulp brightness by about 2.5 ISO
Brightness (deinked pulp to PM)
60
The ink has strong absorption at wavelengths over 700
55 50
(e.g. from 62 to 59.5%). To counter this brightness loss with bleaching
Laboratory residual ink content (ERIC) vs. inline sensor ERIC measurement.
nm and causes a drop in reflectance index. The effective 0
5
10
15
20
Time, hours
we should increase fiber brightness from 62 to 68%. Brightness increase
residual ink test method, ERIC, is based on the absorption of infrared light.
with DIP is roughly only 50% of the increase which we can achieve with
Normal process variation in flotation. Ash consistency
virgin pulp in bleaching.
measured in inlet and Brightness measured on outlet.
7 Before Pulp Storage Prior to pulp storage, brightness, residual
Measurements to the paper machine serve
Optimized Solutions for Your Process
ink, and dirt count will provide valuable
as the final quality assurance and in some
We hope that this process description has
information on quality to the paper
mills can be used for blending operations
served as an introduction to the possibilities
6 Dispersion and Post Flotation
machine. Overall trends can be identified
before the paper machine to achieve
of good RCF measurements that will
quickly and adjustments made to the
required strength or brightness targets.
provide the desired final product quality at
Brightness, residual ink and dirt count can
process. In extreme cases, decisions to
be measured with PulpExpert. Conditions
recirculate out of specification pulp or treat
Brightness Monitoring in DIP Process
environmental impact. There are many
should be controlled to achieve the
it differently can be made with confidence
with the Inline Brightness Sensor
modifications, differences and
maximum dispersed ink removal.
before it contaminates the storage tower.
improvements that can be made to the
Additionally kajaaniCORMECi can also be
As well as deinked pulp brightness and dirt
example process we have used. Please
used for a continuous brightness and ink
count, PulpExpert can measure other pulp
contact your local Metso Automation
paper product is below 60 – 65% ISO,
content monitoring to control these final
properties such as strength and color. If a
resource to find the optimum configuration
adding peroxide into the pulper is often
deinking steps. Ash content is very
final reductive bleaching stage is in use,
for your process as well as the insight we
enough. For higher brightness multistage
important as minimal variation is needed
kajaaniCORMECi can provide slow feedback
have gained in other applications.
bleaching is needed, including both
to ensure good runnability on the paper
correction to the hydrosulfite stage control
Feed consistency to screening is important
oxidative and reductive bleaching
machine.
with the continuous brightness, residual
to ensure the maximum removal of
chemicals. Brightness and residual ink can
contaminants including dissolved solids
be measured on-line using the
and remaining stickies. Consistency control
kajaaniCORMECi brightness transmitter and
SmartPulp Valmet
is normally done in two stages using
used for a feedforward control strategy. The
blade consistency
SmartPulp consistency transmitters with
brightness loss caused by ink in pulp is hard
transmitter
blades specially designed for this
to counter by bleaching alone because the
application. In addition to dirt count,
pulp brightness has to be much higher to
PulpExpert's absolute consistency
counteract optical properties of the residual
measurement can provide continuous
ink. Stable pulp brightness after the
tuning for superior accuracy even with
bleaching tower is thus very difficult to
varying pulp components.
achieve if the ink content varies a lot.
5 Bleaching If the brightness requirement for the final
4 Cleaning and Fine Screening
ink and L-a-b color measurements.
8 Final Quality
the most economical level while minimizing
Pulp brightness at different stages of DIP process; 1. After first flotation, 2. After second flotation and 3. After hydrosulphite bleaching – final brightness. 10 % more magazine paper in the raw material means 1 % higher brightness.
kajaani
North America 3100 Medlock Bridge Road, Suite 250 Norcross, GA 30071 USA Tel. +1 770 446 7818 Fax +1 770 242 8386 Latin America Av. Central 181, Chácaras Reunidas 12238-430 São José dos Campos SP Brazil Tel. +55 12 3935 3500 Fax +55 12 3935 3535 Asia Pacific 501 Orchard Road #05-09 Wheelock Place 238880 Singapore Tel. +65 673 552 00 Fax +65 673 529 55 www.metsoautomation.com
B48 42.1_EN © Metso Automation, 8/2002
Europe Levytie 6 , P.O. Box 310 FIN-00811 Helsinki Finland Tel. +358 20 483 150 Fax +358 20 483 151
Printed on recycled paper manufactured from 100% post consumer waste.
Metso Automation Field Systems Kehräämöntie 3 , P.O. Box 177 FIN-87101 Kajaani Finland Tel. +358 20 483 120 Fax +358 20 483 121
Recycled Fiber Management The Key To Better Paper Quality