Transcript Dia 1

New Micropolymer Technologies for Increased Drainage and
Retention for both Wood and Non Wood Containing Furnishes
Ulf Stenbacka, Christopher Lewis & Marco Polverari
Kemira Oyj
Outline
Brief Review of Retention Mechanisms
Characterization of New Micropolymer Dispersion Technology
A. Structure
B. Synergies
C. Retention Mechanisms
Pilot Studies
A. Alkaline Fine Paper
Case Studies
A. Alkaline Fine Paper – Strength
B. Alkaline Fine Paper – Dusting
C. Alkaline Fine Paper – Production
Conclusions
Retention Mechanisms
Narrow balance exists to achieve optimal retention and formation
• Runnability vs. Quality
Dispersed colloids deposit onto fines and fibre to form flocs
• Retained by filtration
Adsorption of small particles becomes more challenging as furnish
exposed to greater hydrodynamic shear stress
• Increasing machine speed
Increased complexity with the presence of ash and elevated ash
load
Traditional Retention Chemistries
Poly-acrylamides (PAM’s) are efficient for
gross retention
• High molar mass long chain polymers
• Generally linear some structured
versions
Development of large flocs via ‘bridging”
mechanism to achieve sufficient retention
of fillers and fines
• Sheet structure = “hard flocced” or macro
flocculated
PAM’s can agglomerate filler particles
• Effectively increase average particle size
• Optical efficiency can be compromised
PAM created floc can contain a substantial level
of bound water
Former drainage improved but pressing
efficiency decreased
Traditional Retention Chemistries
High charged low molar mass polymers
allow for fixation or patch retention
• Fillers, fines, detrimental substances
Can improve drainage via soluble charge
control
Retention limited due to lack of floc
structure
Necessary application rate for reactivity
can overly decrease cationic demand
• Inhibit retention of other process additives
Next Generation Micropolymers
Creates floc and subsequent sheet structure that maximizes former drainage
without compromising pressing efficiency
Very effective for retention of ash
• Calcium carbonates (precipitated and ground)
• Kaolin
• Calcium Silicate
Unique structure and composition enables them to be reactive in low and high
ash environments and in wood and non wood containing furnishes
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•
•
•
•
SC
News
LWC
Printing and Writing
Unbleached/Bleached Board
Unique synergies when applied in conjunction with traditional inorganic
microparticle technologies
• Colloidal Silica
• Swellable Minerals (Bentonite)
Advanced Micropolymer Technology
A Dual System in a Single Application
A controlled molecular weight cationic or anionic polyacrylamide polymerized
within a coagulant matrix. The coagulant matrix is either:
• Inorganic coagulant (Sulfate salt)
• Organic coagulant (e.g. polyamine)
In order to distinguish these new products from conventional water-in-oil
emulsions the name “water-in-water dispersion” has been chosen
The coagulant matrices of these products is responsible for the fixation of
anionic trash, and the high-molecular species for the retention of fibres and
fillers
Inclusion of hydrophobic associative monomers
• Cationic and anionic versions
• Forms ‘hydrogel’ polymer
• Strongly hydrogen bonding
Fennosil® Micropolymers
Cationic Micropolymers
Average
Product Charge Density Mol. Wt. x E06
(meq/g)
E-130
E-128
ES-325
E-126
5,30
5,44
2,06
5,02
5
5
7
8
Solids
Mole % Charge
34%
34%
20%
36%
40
30
10
10
Chemistry
AM/p-amine
AM/p-DADMAC
AM/Salt
AM/p-amine
Anionic Micropolymers
Product
ES-210
ES-211
Solids
25
25
Mol. Wt. x E06 Mole % Charge
5
-30
5
-13
Chemistry
AM/AA + salt
AM/AA + salt
Product Characteristics
Schematic Illustration Micropolymer Series
Water
Coagulant
Micropolymer Drop
(~ 3 μm)
Lower
MW
Water
PAM
Higher MW
Product: Technology
Hydrophobic groups incorporated
to HMW/LCD polyelectrolyte
Hydrophobic groups lead to inter
and/or intra molecular interactions
•
•
•
•
Formation of micelles
Higher solution viscosity
Higher elasticity
More structure
Hydrophobe
Properties
20
18
Pure PEI
Charge Density (meq/g)
16
14
DMA-Epichlorohydrin
12
Modified PEI
10
8
NEW Micropolymers
(Cationic)
6
4
p-DADMAC
2
CATIONIC PAM'S
0
0
1
2
3
4
5
6
7
8
Molecular Weight (MM)
9
10
11
12
13
14
Micropolymer Retention/Drainage Mechanism
Micropolymer unique charge and structural properties allows (cationic) polymer to control
anionic trash while retaining fibres and fillers
Floc structure advantageous for both retention and drainage
•
•
Increased dewatering in former
Increased dewatering in press
Fines and filler flocculated along the long fibres as small discrete flocs
•
•
Minimize level of bound water
Reduction of blocking of inter-fibre pores
Floc
Wood Fiber
Wood Fiber
Floc
Wood Fiber
Floc
Floc
WLF204
Conventional System
WLF204
Micropolymer System
Effect of Fennosil E on Ash Retention and Distribution
Electro-micrograph of filler distribution prior to
Fennosil E-325 conversion.
Electro-micrograph of filler distribution after
Fennosil E-325 conversion.
Pilot Study A: Strength and Structure Enhancement
Pilot machine study conducted using alkaline fine paper
Primary objective of the study was to increase sheet ash to 20% while reducing
use of starch
Applied cationic potato starch pre-shear at 2 kg/T (1/3 regular dosage)
Applied cationic PAM pre-shear at ½ regular dosage
Applied silica and anionic dispersion micropolymer post shear simultaneously
Relate gains to the resulting sheet structure
Fibre and Process Characteristics
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•
•
•
•
ASA size
Precipitated calcium carbonate (PCC) used for filler
Cationic potato starch
OBA added at both size press and wet-end
Sheet ash 16-18% maximum
250
240
230
220
210
200
190
180
170
160
150
1200
1100
1000
900
800
700
600
500
400
0
0.2
0.5
0.7
1
Anionic Dispersion Micropolymer Dosage (kg/t)
Scott Bond
Dosage of PCC = 6.0 kg/t
Ash in sheet = 28%
FS-515 dosage = 0.7 kg/t (active)
TEAindex
TEAindex (mJ/g)
Scott Bond (Jsm)
Pilot Study A: Scott Bond and TEA
Increasing ASMP has a
significant positive effect on
internal bond strength
•
35% improvement
Increasing ASMP has a
significant positive effect on
tensile strength
•
30% improvement
1.0
4.4
4.2
4.0
3.8
3.6
3.4
3.2
3.0
0.8
0.6
0.4
0.2
0.0
0
0.2
0.5
0.7
1
Anionic Dispersion MP Dosage (kg/t)
Breaking Length
Specific Form ation
Ash in sheet = 28%
Colloidal Silica dosage = 0.7 kg/t (active)
Spec. Formation
(Sq. rt g/m)
Breaking Length (km)
Pilot Study A: Breaking Length and Specific Formation
Increasing ASMP has a
significant positive effect on
tensile strength
•
25% improvement
Increasing dosage of anionic
micropolymer improved
formation. The lower the
number the better the
formation.
•
40% improvement
Case A: Uncoated Free Sheet
Machine Type:
Objective:
Grades:
Sheet Ash:
Top Former
Improve ash retention and strength to
potentially increase sheet ash target
Offset, Xerographic
15% - 18%
Incumbent Program:
Silica (0.60 – 0.75 kg/t) and Cationic Potato Starch (4 – 5 kg/t)
Other Wet End Chemistry:
Alkenyl Succinic Anhydride (ASA) Sizing, Precipitated Calcium
Carbonate, Alum
Proposed Chemistry:
Application:
Anionic Dispersion Micropolymer Chemistry + Colloidal Silica
Anionic Dispersion Micropolymer (0.15 – 0.4 kg/t) applied post
shear with existing silica (0.25 – 0.35 kg/t)
Case A: Retention
Silica Starch
Anionic Dispersion MP/Silica
First Pass Retention/First Pass Ash Retention
90
85
Significant increase in ash
retention across all the
grades
80
75
70
Improved additive
efficiency: OBA & Size
65
60
This achieved with 40%+
reduction in application rate
of colloidal silica
55
50
45
Ability to evaluate lower
cost starch
40
35
30
Xerographic
(FPR)
Xerographic
(FPAR)
Offset 50#
(FPR)
Offset 50#
(FPAR)
Offset 60#
(FPR)
Offset 60#
(FPAR)
Anionic Dispersion MP applied post screen (shear) applied with colloidal silica
Applied with Cationic Starch
•
•
Some loss in efficiency
Improved retention over
incumbent program with
potato
Case A: Strength (Tear)
76
Silica Starch
Anionic Dispersion MP/Silica
75
74
MD/CD Tear (mN)
73
72
71
70
69
68
67
66
Anionic Dispersion MP applied post screen (shear) applied with colloidal silica
Applied with Cationic Starch
Offset 60# (MD
Tear)
Offset 60# (CD
Tear)
Offset 50# (MD
Tear)
Offset 50# (CD
Tear)
Xerographic
(MD Tear)
Xerographic (CD
Tear)
65
Significant increase in both
MD and CD tear
Case A: Strength (Tensile/Burst)
38
Silica Starch
Anionic Dispersion MP/Silica
34
Significant increase in
tensile strength
32
30
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•
28
26
24
CD and MD
Burst
With increased strength
potential to increase sheet
ash target by 3% (20%
total)
22
20
18
16
14
Achieved in trials
12
Anionic Dispersion MP applied post screen (shear) applied with colloidal silica
Applied with Cationic Starch
Offset 60# (MD
Tensile)
Offset 60# (CD
Tensile)
Offset 60#
(Burst)
Offset 50# (MD
Tensile)
Offset 50# (CD
Tensile)
Offset 50#
(Burst)
Xerographic
(MD Tensile)
Xerographic (CD
Tensile)
10
Xerographic
(Burst)
MD/CD Tensile (kN/m)/Burst (kPa)
36
•
Done with both corn and
potato starch & without
significantly increasing
retention chemistry
Potential for significant
savings in fibre cost
Case Study B: Uncoated Free Sheet
Machine Type:
Objective:
Top Wire Former
Increase sheet ash by 1% - 2% without
negatively impacting sheet strength
or increasing dusting propensity.
Grades:
Xerographic
Basis Weights:
80 – 90g/m2
Sheet Ash:
Machine Speed (Range):
Furnish Components:
Incumbent Program:
Other Wet End Chemistry:
Proposed Program:
22%
950 - 1000 m/min
Bleached Hardwood 50% , Softwood 50% Broke 20% - 30+%
Silicated PAC + Anionic PAM
Alkenyl Succinic Anhydride (ASA) Sizing, Precipitated Calcium
Carbonate, Starch, Alum
Anionic Dispersion Micropolymer applied with existing Anionic
PAM (A-Pam) and silicated PAC system
Case Study B: Retention/Dosage (On-Line)
white water solids (g/L)
Headbox Ash (g/L)
Anionic Dispersion MP Application Rate
3
Trial Start
2.8
1000
900
Break
700
600
2.2
500
2
400
1.8
300
1.6
200
1.4
100
10:00
9:20
8:25
1:00
22:40
20:40
16:00
14:00
12:10
11:00
9:30
8:30
0:00
18:00
13:35
12:35
0
11:30
1.2
10:50
WW Solids (g/L)
2.4
Retention Additive Application Rate (g/t)
800
2.6
Anionic Dispersion
Micropolymer introduced in
addition to existing A-PAM
and silicated PAC
chemistry
•
Co-Mixed with A-PAM
Immediate decrease in
headbox ash
•
2.9 g/L to 2.2 g/L
Immediate decrease in
white water solids
•
0.163 g/L to .137 g/L
Case Study B: Retention (Lab)
FPR
First Pass Retention/First Pass Ash Retention (%)
80.0
FPAR
75.0
70.0
Increase in First Pass Ash
Retention better than 10+
points
65.0
60.0
Achieved both at equal
and with sheet ash levels
at 1% and 2% greater
55.0
50.0
45.0
57.2
55.8
57.6
40.0
46.3
43.4
35.0
30.0
Pre-Trial 22% Sheet
Ash
Trial 22% Sheet
Ash
Trial 23% Sheet
Ash
Trial 24% Sheet
Ash
Post Trial 22%
Sheet Ash
Case Study B: Dusting
450.0
400.0
Average Dust Level (mg/10000)
350.0
Decreased dusting level
at equal ash
439.3
405.5
402.0
300.0
250.0
Dusting propensity did
not increase with higher
sheet ash load
315.7
200.0
Sheet ash increment of
2% (24%) at equal dust
level as 22% sheet
150.0
100.0
50.0
0.0
average 22% ash
before the trial
average 22% ash 450 average 23% ash 625 average 24% ash 800
g/t Anionic Dispersion g/t Anionic Dispersiong/t Anionic Dispersion
MP
MP
MP
Case Study B: Defects
6
ULMA Defects 01-02 (count/m2)
5
ULMA Defects 01 – 02
reduced by 45+%
4
3
6.0
5.5
4.3
2
3.0
3.0
Lowest defect level
achieved at highest ash
loading
•
•
•
1
0
average 22% ash average 22% ash average 23% ash average 24% ash average 22% ash
before the trial
450 g/t Anionic
625 g/t Anionic
800 g/t Anionic
after the trial
Dispersion MP
Dispersion MP
Dispersion MP
Function of transition
22% data included startup
“Cleaning-Up” of wet end
Mill Case C: Uncoated Free Sheet
Machine Type:
Objective:
Grades:
Sheet Ash:
Incumbent Program:
Other Wet End Chemistry:
Fourdrinier
Replace existing retention program to
improve formation and increase production
Lt. Wt. Opaque, Offset, Text
12% - 16%
Bentonite, Linear C-Pam, Cationic Potato Starch
Alkenyl Succinic Anhydride (ASA) Sizing, Precipitated Calcium
Carbonate
Proposed Chemistry:
Anionic Dispersion Micropolymer Chemistry, A-Pam, and polyaluminium chloride (PAC)
Application:
Anionic Dispersion Micropolymer (0.6 – 1.0 kg/t) applied post shear
with A-Pam (0.2 – 0.5 kg/t) applied pre shear, and PAC (1 – 2 kg/t)
applied pre A-Pam
Mill Case C: Production
14.5
+15.7%
C-PAM/Bentonite
14.0
A-PAM/Anionic Dispersion MP
+5.7%
13.5
+2.1%
Production Rate (t/hr)
13.0
+2.8%
Significant increase in
production across majority of
grades
+5.4%
12.5
12.0
•
As much as 15+%
11.5
+3.8%
11.0
This achieved despite that presize press moisture was reduced
as much as 0.7%
10.5
10.0
•
9.5
9.0
35# Lt. Wt.
Opaque
50# Book
55# Book
40# Offset
Anionic Dispersion MP applied post screen (shear)
A-Pam applied pre-screen (shear)
PAC applied at fan pump (pre A-Pam)
60# Offset
60# Copy
Bentonite program pre size
press moisture average
approximately 1.6%
Higher is Better
Mill Case C: Formation
55.0
C-PAM/Bentonite
50.0
A-PAM/Anionic Dispersion MP
45.0
MK Formation
40.0
Formation improved across
majority of the grades
35.0
•
At least equal
30.0
Grades with largest improvement
in formation also saw an average
of ½ point increase in opacity
25.0
•
•
20.0
50#, 55# book
40# Offset
15.0
10.0
35# Lt. Wt.
Opaque
50# Book
55# Book
40# Offset
Higher formation values are better
Anionic Dispersion MP applied post screen (shear)
A-Pam applied pre-screen (shear)
PAC applied at fan pump (pre A-Pam)
60# Offset
60# Copy
Grades where equal, generally
greatest increase in production
Mill Case C: Additive Efficiency
12.0
C-PAM/Bentonite
11.0
A-PAM/Anionic Dispersion MP
10.0
Significant starch reduction
across all the grades
Starch Usage (kg/t)
9.0
•
•
•
8.0
7.0
1.5 – 3.0 kg/t
No loss in retention
FPAR as high as 80% on some
grades
6.0
5.0
Quality not compromised
4.0
3.0
2.0
35# Lt. Wt.
Opaque
50# Book
55# Book
40# Offset
Anionic Dispersion MP applied post screen (shear)
A-Pam applied pre-screen (shear)
PAC applied at fan pump (pre A-Pam)
60# Offset
60# Copy
Sizing response equal or better
at equivalent or lower ASA
application rate
Conclusions
A new generation of cationic and anionic micropolymer
dispersions has been developed
Unique synergies exist with co-application of the micropolymer
dispersions with traditional inorganic microparticle technologies
Chemistries are robust enough to be applied in a wide range of furnishes
Unique composition and structure allow them to increase sheet
dewatering while significantly increasing retention in both low and high
ash environments
Chemistry shows ash selectivity, particularly with presence of
(precipitated) calcium carbonate
Significant increase in retention quality exhibiting lower propensities for
dusting
Sheets formed with this technology impart greater strength (wood free) –
significant increases of both tear and tensile have been observed
Appreciable increases in drainage have been observed
Thank you