Use and Fiber Savings in GhiG raphic GdG rades ppt.pdfNew Technology for Increased Filler Use and...

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

2PaperCon2011, Covington, KY


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



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

PaperCon2011, Covington, KY


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



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


PaperCon 2011 26

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



Filler Preflocculation Technology

Increase filler particle size and reduce the interference with fiber fiber bondingwith fiber‐fiber bonding

UntreatedFiller

Prefloc.Filler



Why Not Use Larger Sized Filler Particle?



Why not Use Larger Sized Filler Particle?



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



Controllable Preflocculationwith Improved Particle Size Distributionp

C i l M h d N M th dConventional Method New Method



Controllable Preflocculationwith Improved Shear Stabilityp y



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



Effect of Preflocculation on Strength



Effect of Preflocculation on Opacity



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



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



Steam Reduction with Increased Filler Content


Treatment started


Steam Reduction with Increased Filler Content



Impact on First Draw

Treatment started


Treatment started


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.



Use and Fiber Savings in GhiG raphic GdG rades ppt.pdfNew Technology for Increased Filler Use and...

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