New Technology for Increased FillerNew Technology for Increased Filler Use and Fiber Savings i G hi G din Graphic Grades
05/02/2011
W i Ch Ph DWeiguo Cheng, Ph.D
Nalco Company
1
Nalco and the logo are trademarks of Nalco Company
p y
PaperCon 2011 Page 621
Outline
• Introduction– Impact of Fillers on Sheet Properties
– Challenges of Increasing Filler Contentg g
• Effects of Filler Preflocculation Technology on Sheet Properties p
– Pilot Machine Study
Commercial Application– Commercial Application
• Summary
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Fillers in Papermaking
• Fillers were introduced into papermaking for improving sheet propertiesfor improving sheet properties– Optical properties, print quality, smoothness
• Filler is much smaller than fiber Interference with fiber‐fib b difiber bonding
Interference with wet‐end chemicalsend chemicals Sizing agent Strength agent
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Why Is Higher Filler Content Desired?
• Fiber substitution1000
SBSKFiber substitution ‐> cost savings– Kraft 850$/ton; 800
900
/tonn
e)
SBSK
NBHK
Kraft 850$/ton;
– PCC 100$/ton700
800
ce in
US
($/
• Energy savings500
600Pu
lp P
ric
4001/3/2008 6/1/2008 10/29/2008 3/28/2009 8/25/2009 1/22/2010 6/21/2010
Ti
4
Time
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Challenges in Higher Filler Usage
Sheet Strength d
Dusting and k
55
Reduction Picking
45
50
stre
ngth
ndex
Nm
/g)
35
40
She
et s
(ten
sile
in
3019 21 23 25 27 29 31
% Filler in sheet
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More Challenges in Higher Filler Usage
• Sheet Properties Loss Internal sheet strength reduction– Internal sheet strength reduction
– Surface strength reduction– Bulk loss
• Poor Machine RunnabilityWet web strength reduction– Wet web strength reduction
– Press picking
R t ti d Sh t F ti• Retention and Sheet Formation– Fillers are harder to retain– Increased retention chemicals leads to poor formation– Increased retention chemicals leads to poor formation
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Traditional Methods of Increasing Filler Content
• Furnish Optimization– Composition, Refining
• Filler Optimizationp– PCC vs. GCC
– Size and morphologyp gy
• Wet end chemical optimization– RDF program
– Size press formula
D t th dditi– Dry strength additives
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Filler Preflocculation Technology
Increase filler particle size and reduce the interference with fiber fiber bondingwith fiber‐fiber bonding
UntreatedFiller
Prefloc.Filler
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Why Not Use Larger Sized Filler Particle?
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Why not Use Larger Sized Filler Particle?
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Challenges of Filler Preflocculation
• Proper filler flocs size and size distribution
Fill fl t b h• Filler flocs to be shear resistant
L h i d
Hurting Sheet Strength
– Large shear in modern high speed paper‐machine
• Economical• Economical
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Controllable Preflocculationwith Improved Particle Size Distributionp
C i l M h d N M th dConventional Method New Method
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Controllable Preflocculationwith Improved Shear Stabilityp y
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Pilot Machine Trial Conditions
• EuroFEX gap‐former pilot machine at Innventia
• Machine speed: 1000 m/min
• Grade: 75 gsm sheet at 20%, 25% and 30% ash
• Furnish: 85/15 eucalyptus (26 SR) / pine (22 SR)
• Filler: Untreated or preflocculated dispersed PCC p p
• Chemical Additives 7 5 kg/ton starch 4 5 kg/ton OBA 6 kg/ton AKD 7.5 kg/ton starch, 4.5 kg/ton OBA, 6 kg/ton AKD,
cationic flocculant (dosage varied), 5 kg/ton microparticle
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Effect of Preflocculation on Strength
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Effect of Preflocculation on Opacity
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Case Study of Commercial Application
• Grade: Coated freesheet, off‐machine coater
i i h f b h 06• Basis weight of base sheet: 106 gsm
• Machine Speed: 1400 m/min
• Filler– Starting ash content: 17%
Fill 100% PCC– Filler: 100% PCC
• Wet end chemicals5 k /t d t th t– 5 kg/ton dry strength agent
– 9.5 kg/ton cationic starch
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Effects of Preflocculation on Sheet Properties
Highlights: fAsh content increased from 17% to 22%, or 5%
Critical sheet strength properties were maintained
Opacity increased
Bulk loss was 1.5%, which was recovered by furnish yoptimization
Tear and stiffness decreased slightly, but within specsg y, p
400% ROI
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Steam Reduction with Increased Filler Content
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Treatment started
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Steam Reduction with Increased Filler Content
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Impact on First Draw
Treatment started
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Treatment started
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Summary
• With increasing fiber prices, increasing the ash content in graphic paper can significantly decreasecontent in graphic paper can significantly decrease the production costs of papermaking
• Filler preflocculation technology was proven capable of helping papermakers increase filler content by 3% to 5% while maintaining sheet propertiesto 5% while maintaining sheet properties
• Filler preflocculation technology has minimal impact hi bilion machine runnability
• Steam consumption reduced with increased ash.
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