New Technology for Increased Filler Use and Fiber Savings in Graphic Grades 05/02/2011 Wi Weiguo Cheng, Ph.D Nalco Company Nalco and the logo are trademarks of Nalco Company 1 PaperCon 2011 Page 621
Outline Introduction Impact of Fillers on Sheet Properties Challenges of Increasing Filler Content Effects of Filler Preflocculation Technology on Sheet Properties Pilot Machine Study Commercial Application Summary 2 PaperCon 2011 Page 622
Fillers in Papermaking Fillers were introduced into papermaking for improving sheet properties Optical properties, print quality, smoothness Filler is much smaller than fiber Interference with fiber fiber bonding Interference with wet end chemicals Sizing agent Strength agent 3 PaperCon 2011 Page 623
Why Is Higher Filler Content Desired? Fiber substitution 1000 900 > cost savings Pulp Pric ce in US ($/ /tonne) Kraft 850$/ton; 800 PCC 100$/ton Energy savings 700 600 500 SBSK NBHK 400 1/3/2008 6/1/2008 10/29/2008 3/28/2009 8/25/2009 1/22/2010 6/21/2010 Time 4 PaperCon 2011 Page 624
Challenges in Higher Filler Usage Sheet Strength Reduction Dusting and Picking 55 strength ndex Nm/g) Sheet s (tensile in 50 45 40 35 30 19 21 23 25 27 29 31 % Filler in sheet 5 PaperCon 2011 Page 625
More Challenges in Higher Filler Usage Sheet Properties Loss Internalsheet strength reduction Surface strength reduction Bulk loss Poor Machine Runnability Wet web strength reduction Press picking Rt Retention ti and Sheet Formation Fillers are harder to retain Increased retention chemicalsleads leads to poorformation 6 PaperCon 2011 Page 626
Traditional Methods of Increasing Filler Content Furnish Optimization Composition, Refining Filler Optimization PCC vs. GCC Size and morphology Wet end chemical optimization RDF program Size press formula Dry strength thadditives 7 PaperCon 2011 Page 627
Filler Preflocculation Technology Increase filler particle size and reduce the interference with fiber fiber bonding Untreated Filler Prefloc. Filler 8 PaperCon 2011 Page 628
Why Not Use Larger Sized Filler Particle? 9 PaperCon 2011 Page 629
Why not Use Larger Sized Filler Particle? 10 PaperCon 2011 Page 630
Challenges of Filler Preflocculation Proper filler flocs size and size distribution Filler flocs to be shear resistant Large shear in modern high speed paper machine Economical Hurting Sheet Strength 11 PaperCon 2011 Page 631
Controllable Preflocculation with Improved Particle Size Distribution Conventional lmethod New Mthd Method 12 PaperCon 2011 Page 632
Controllable Preflocculation with Improved Shear Stability 13 PaperCon 2011 Page 633
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 Chemical Additives 7.5kg/tonstarch starch, 4.5kg/tonOBA OBA, 6 kg/tonakd AKD, cationic flocculant (dosage varied), 5 kg/ton microparticle 14 PaperCon 2011 Page 634
Effect of Preflocculation on Strength 15 PaperCon 2011 Page 635
Effect of Preflocculation on Opacity 16 PaperCon 2011 Page 636
Case Study of Commercial Application Grade: Coated freesheet, off machine coater Basis weight ihof base sheet: 106 gsm Machine Speed: 1400 m/min Filler Starting ash content: 17% Filler: 100% PCC Wet end chemicals 5 kg/ton dry strength thagent 9.5 kg/ton cationic starch 17 PaperCon 2011 Page 637
Effects of Preflocculation on Sheet Properties Highlights: Ash 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 optimization Tear and stiffness decreased slightly, but within specs 400% ROI 18 PaperCon 2011 Page 638
Steam Reduction with Increased Filler Content Treatment started 19 PaperCon 2011 Page 639
Steam Reduction with Increased Filler Content 20 PaperCon 2011 Page 640
Impact on First Draw Treatment started 21 PaperCon 2011 Page 641
Summary With increasing fiber prices, increasing the ash content 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 properties Filler preflocculation technology has minimal impact on machine runnability Steam consumption reduced with increased ash. 22 PaperCon 2011 Page 642