Removing the Unknown. Lap Pulp Colloidal Stickies to Improve Paper Machine Runnability

Transcription

1 Removing the Unknown of Lap Pulp Colloidal Stickies to Improve Paper Machine Runnability Danny Haynes Senior Technical Coordinator PaperCon 2011 Page 1989

2 Introduction of Recycle Lap Pulp? Most Printing and Writing grades are seeking to increase usage of recycle fiber. A critical barrier to the use of recycle fiber is the inclusion of stickies Stickies lead to deposition issues and runnability problems such as scratching at the coater Most recycle fiber comes in as lap pulp Quality Criteria can include Brightness Macrostickies Fiber Properties Ash Content PaperCon 2011 Page 1990

3 Stickies - The Unknown of Recycle Lap Pulp? chance, Even with a macrostickies count paper machine can have deposit/stickies issues Papermakers want to know if a given lot of lap pulp will run well or have issues. The perception is that it is by chance a roll of the dice, that a given run of lap pulp will go well. This mindset limits the desire to use recycle fiber. PaperCon 2011 Page 1991

4 What is Unknown about the Stickies in Recycle Lap Pulp? p Macrostickies m - how many/can be seen/counted Macrostickies - m -33% of Fine Screens in Lap Pulp Plants Macrostickies - 75 m -Behavior same as larger macrostickies Suspended stickies 20 to 75 m Dispersed stickies 1 to 25 m Colloidal stickies 0.5 to 5 m Dissolved stickies less than 5 nm PaperCon 2011 Page 1992

5 Testing for Invisible and Visible Impact Fractionate t Total Organic Carbon 25 m 5nm Invisible = Colloidal Stickies Fractionate Soak and Measure Tackiness 25 m 85 o C Visible = Tackiness PaperCon 2011 Page 1993

6 Relationship Between Colloidal Organics & Tackiness High Tackiness typically seen at operations having deposit/stickies issues (g f /m) Tackiness Filtrate Tackiness of Filtrate below 25 microns based on TOC and Sample Source High Tackiness Low Tackiness Expected Tackiness Newsprint Office TMP GWD Coated Broke Kraft OCC Colloidal Organics (ppm-toc) PaperCon 2011 Page 1994

7 Shear Stress Test Analysis Does the amount of colloidal organics (the invisible stuff) change? Increase Increase shearing broke into pieces generating more Caution potential to over whelm/over load the process Increasing means no agglomeration Same stable/equilibrium Decrease where did it go? It deposited out onto fiber, fines, filler & surfaces Same Decrease 7 PaperCon 2011 Page 1995

8 Shear Stress Response for Problem Lap Pulp Lap Pulp that t had been identified to cause issues saw a decrease in colloidal organics under stress Agglomeration of colloidal seen to result in runnability issues due to recycle pulp Stickies (pp pm-toc) Colloidal Reaction of Lap Pulp at 4% Consistency to Shear Stress Diluted with Tap Water -24% -59% -37% -12% -18% -91% Lap Pulp A Lap Pulp B High Macro-stickies Count Lap Pulp C Lap Pulp D Lap Pulp E Lap Pulp F Lap Pulp G -20% -32% -26% 0 min min min 35 Repulper Stressful High Stress Mixing Time to Colloidal Shear Stress Test PaperCon 2011 Page 1996

9 ?X Measuring the Unknown / Unseen Stickies Lap Pulp that t is stable Seen to increase or remain the same under stress Increase Tac ck (g force per meter) 50 Expected Tackiness for Lap Pulp at 4% Diluted with Tap Water Lap Pulp that has low Same 30 or expected tackiness 20 That has a no No paper machines issues tackiness or low 10 Sample considered to tackiness have no tackiness 0 Tackiness on or Decrease below expected Colloidal Stickies (TOC-ppm) tackiness Expected Tackiness Within 10% Good Below is Best PaperCon 2011 Page 1997

10 Example 1 Unstable & No Tackiness No Issues on Paper Machine Colloidal Stickies (TOC C-ppm) Diluted With Tap Water Partially Unstable 0 min of Repulping 15 min - Stressful 30 min - High Stress 0-kg 1 kg 2 kg Unstable No Tackiness Tack (g force per me eter) kg Slightly abo ove expected Expected Tackiness On or Below the Line is Best 0-kg 1 kg 2kg No paper machine issues Sample has no tackiness Detackifier Treatment Colloidal Stickies (TOC-ppm) PaperCon 2011 Page 1998

11 Example 2 Stable &Tackiness Below Expected No Issues tickies (TOC C-ppm) Colloidal S Diluted With Tap Water All Lots Stable 0 min of Repulping 15 min - Stressful 30 min - High Stress Lot #1 Lot #2 Lot #3 Lot #4 Tack (g force per me eter) All Below Ex xpected Tack kiness Lot #4 Lot #3 Lot #2 Lot #1 Expected Tackiness On or Below the Line is Best No paper machine issues Sample has no tackiness All Lots Treated with Detackifier Colloidal Stickies (TOC-ppm) PaperCon 2011 Page 1999

12 Example 3 Stable & Treatment Moves Tackiness Below Expected No Issues tickies (TOC C-ppm) Colloidal S 80 Diluted With Tap Water 0 min of Repulping 15 min - Stressful 30 min - High Stress All Lots Stable #1-0 kg #2-0 kg #3-2 kg #4-2 kg Treated More Stable Untreated & Treated with Detackifier Tack (g force per me eter) Treatment Lowers Tacki iness Expected Tackiness On or Below the Line is Best #2-0 kg #1 #3-02 kg No paper machine issues #4-2kg Sample has no tackiness Colloidal Stickies (TOC-ppm) PaperCon 2011 Page 2000

13 Lap Pulp is Not Always the Problem Colloidal Stickies (ppm m-toc) Two Lap Pulps Stable with Tap Water Lap Pulp at 4% Consistency Diluted with Tap Water Lap Pulp X Lap Pulp Y 0 min min min35 Repulper Stressful High Stress Stickies (pp pm-toc) Colloidal Two Lap Pulps Unstable with Paper Machine White Water Lap Pulp at 4% Consistency Diluted with Paper Machine White Water Lap Pulp X Lap Pulp Y PM WW 30% dec 130 Expected to be at 190 (170+20) 50% decrease Expected to 45% dec be at 230 (170+) % decrease min min min35 Repulper Stressful High Stress Mixing Time to Colloidal Shear Stress Test PaperCon 2011 Page 2001

14 Remove the Unknown about the Stickies in Recycle Lap Pulp? X? p X Macrostickies m - how many/can be seen/counted Macrostickies - m -33% of Fine Screens in Lap Pulp Plants Macrostickies - 75 m -Behavior same as larger macrostickies Suspended stickies 20 to 75 m Dispersed stickies 1 to 25 m Colloidal stickies 0.5 to 5 m Dissolved stickies less than 5 nm Colloidal Stability & Tackiness PaperCon 2011 Page 2002

15 If Colloidal Stickies are Unknown It can be a Roll of the Dice with Recycle Lap Pulp? PaperCon 2011 Page 2003

16 Remove the Unknown about the Stickies in Recycle Lap Pulp by Knowing Colloidal Behavior Colloidal Stickie s (TOC-ppm) 80 Diluted With Tap Water 0 min of Repulping 15 min - Stressful 30 min - High Stress #1-0 kg #2-0 kg #3-2 kg #4-2 kg Untreated & Treated with Detackifier Tack (g force per meter) #2-0 kg #1 #3-02 kg #4-2 kg Expected Tackiness On or Below the Line is Best No paper machine issues Sample has no tackiness Colloidal Stickies (TOC-ppm) Colloidal Stability & Tackiness PaperCon 2011 Page 2004

17 Thank You for your attention. Questions? PaperCon 2011 Page 2005