New Micropolymer Technologies for Increased Drainage and Retention for both Wood and Non Wood...
-
Upload
bethany-bayle -
Category
Documents
-
view
217 -
download
1
Transcript of New Micropolymer Technologies for Increased Drainage and Retention for both Wood and Non Wood...
New Micropolymer Technologies for Increased Drainage and New Micropolymer Technologies for Increased Drainage and Retention for both Wood and Non Wood Containing FurnishesRetention for both Wood and Non Wood Containing Furnishes
Ulf Stenbacka, Christopher Lewis & Marco PolverariUlf Stenbacka, Christopher Lewis & Marco PolverariKemira OyjKemira Oyj
Outline
Brief Review of Retention Mechanisms
Characterization of New Micropolymer Dispersion TechnologyA. Structure
B. Synergies
C. Retention Mechanisms
Pilot StudiesA. Alkaline Fine Paper
Case StudiesA. 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
• SC• News• LWC• Printing and Writing• Unbleached/Bleached Board
Unique synergies when applied in conjunction with traditional inorganic Unique synergies when applied in conjunction with traditional inorganic microparticle technologiesmicroparticle technologies
• Colloidal SilicaColloidal Silica• Swellable Minerals (Bentonite)Swellable Minerals (Bentonite)
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
Advanced Micropolymer Technology
Fennosil® Micropolymers
ProductAverage
Charge Density (meq/g)
Mol. Wt. x E06 Solids Mole % Charge Chemistry
E-130 5,30 5 34% 40 AM/p-amineE-128 5,44 5 34% 30 AM/p-DADMACES-325 2,06 7 20% 10 AM/SaltE-126 5,02 8 36% 10 AM/p-amine
Cationic Micropolymers
Anionic Micropolymers
Product Solids Mol. Wt. x E06 Mole % Charge ChemistryES-210 25 5 -30 AM/AA + saltES-211 25 5 -13 AM/AA + salt
Product Characteristics
Schematic Illustration Micropolymer Series
Micropolymer Drop(~ 3 μm)
WaterCoagulant
Lower
MW
PAM
Higher MW
Water
Product: Technology
HydrophobeHydrophobe
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
Properties
0
2
4
6
8
10
12
14
16
18
20
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14
Molecular Weight (MM)
Ch
arg
e D
ensi
ty (
meq
/g)
NEW Micropolymers (Cationic)
CATIONIC PAM'S
Pu
re P
EI
Modified PEI
p-DADMAC
DMA-Epichlorohydrin
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
W ood Fiber
W ood Fiber
W ood Fiber
F loc
Floc
Floc
W LF204 W LF204
Conventional System Micropolymer System
Effect of Fennosil E on Ash Retention and Distribution
Electro-micrograph of filler distribution after Fennosil E-325 conversion.
Electro-micrograph of filler distribution prior to 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 CharacteristicsFibre and Process Characteristics• 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
Pilot Study A: Scott Bond and TEA
Dosage of PCC = 6.0 kg/t
Ash in sheet = 28%
FS-515 dosage = 0.7 kg/t (active)
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
150160170180190200210220230240250
0 0.2 0.5 0.7 1
Anionic Dispersion Micropolymer Dosage (kg/t)
Sco
tt B
on
d (
Jsm
)
400500600700800900100011001200
TE
Ain
dex
(m
J/g
)
Scott Bond TEAindex
Pilot Study A: Breaking Length and Specific Formation
Ash in sheet = 28%
Colloidal Silica dosage = 0.7 kg/t (active)
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
3.0
3.2
3.4
3.6
3.8
4.0
4.2
4.4
0 0.2 0.5 0.7 1
Anionic Dispersion MP Dosage (kg/t)
Bre
akin
g L
eng
th (
km)
0.0
0.2
0.4
0.6
0.8
1.0
Sp
ec. F
orm
atio
n
(Sq
. rt
g/m
)
Breaking Length Specific Formation
Case A: Uncoated Free Sheet
Machine Type: Top Former
Objective: Improve ash retention and strength to potentially increase sheet ash target
Grades: Offset, Xerographic
Sheet Ash: 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: Anionic Dispersion Micropolymer Chemistry + Colloidal Silica
Application: Anionic Dispersion Micropolymer (0.15 – 0.4 kg/t) applied post shear with existing silica (0.25 – 0.35 kg/t)
Case A: Retention
Anionic Dispersion MP applied post screen (shear) applied with colloidal silica
Applied with Cationic Starch
Significant increase in ash retention across all the grades
Improved additive efficiency: OBA & Size
This achieved with 40%+ reduction in application rate of colloidal silica
Ability to evaluate lower cost starch
• Some loss in efficiency
• Improved retention over incumbent program with potato
30
35
40
45
50
55
60
65
70
75
80
85
90
Xerographic(FPR)
Xerographic(FPAR)
Offset 50#(FPR)
Offset 50#(FPAR)
Offset 60#(FPR)
Offset 60#(FPAR)
Fir
st P
ass
Ret
enti
on
/Fir
st P
ass
Ash
Ret
enti
on
Silica Starch Anionic Dispersion MP/Silica
Case A: Strength (Tear)
Anionic Dispersion MP applied post screen (shear) applied with colloidal silica
Applied with Cationic Starch
Significant increase in both MD and CD tear
65
66
67
68
69
70
71
72
73
74
75
76X
ero
gra
ph
ic (
CD
Te
ar)
Xe
rog
rap
hic
(MD
Te
ar)
Off
se
t 5
0#
(C
DT
ea
r)
Off
se
t 5
0#
(M
DT
ea
r)
Off
se
t 6
0#
(C
DT
ea
r)
Off
se
t 6
0#
(M
DT
ea
r)
MD
/CD
Te
ar
(mN
)
Silica Starch Anionic Dispersion MP/Silica
Case A: Strength (Tensile/Burst)
Anionic Dispersion MP applied post screen (shear) applied with colloidal silica
Applied with Cationic Starch
Significant increase in tensile strength
• CD and MD
• Burst
With increased strength potential to increase sheet ash target by 3% (20% total)
Achieved in trials• Done with both corn and
potato starch & without significantly increasing retention chemistry
Potential for significant savings in fibre cost
10
12
14
16
18
20
22
24
26
28
30
32
34
36
38
Xe
rog
rap
hic
(Bu
rst)
Xe
rog
rap
hic
(C
DT
en
sil
e)
Xe
rog
rap
hic
(MD
Te
ns
ile
)
Off
se
t 5
0#
(Bu
rst)
Off
se
t 5
0#
(C
DT
en
sil
e)
Off
se
t 5
0#
(M
DT
en
sil
e)
Off
se
t 6
0#
(Bu
rst)
Off
se
t 6
0#
(C
DT
en
sil
e)
Off
se
t 6
0#
(M
DT
en
sil
e)
MD
/CD
Te
ns
ile
(k
N/m
)/B
urs
t (k
Pa
)
Silica Starch Anionic Dispersion MP/Silica
Case Study B: Uncoated Free Sheet
Machine Type: Top Wire Former
Objective: Increase sheet ash by 1% - 2% without negatively impacting sheet strength or increasing dusting propensity.
Grades: Xerographic
Basis Weights: 80 – 90g/m2
Sheet Ash: 22%
Machine Speed (Range): 950 - 1000 m/min
Furnish Components: Bleached Hardwood 50% , Softwood 50% Broke 20% - 30+%
Incumbent Program: Silicated PAC + Anionic PAM
Other Wet End Chemistry: Alkenyl Succinic Anhydride (ASA) Sizing, Precipitated Calcium Carbonate, Starch, Alum
Proposed Program: Anionic Dispersion Micropolymer applied with existing Anionic PAM (A-Pam) and silicated PAC system
Case Study B: Retention/Dosage (On-Line)
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
1.2
1.4
1.6
1.8
2
2.2
2.4
2.6
2.8
3
10:5
0
11:3
0
12:3
5
13:3
5
18:0
0
0:00
8:30
9:30
11:0
0
12:1
0
14:0
0
16:0
0
20:4
0
22:4
0
1:00
8:25
9:20
10:0
0
WW
So
lids
(g/L
)
0
100
200
300
400
500
600
700
800
900
1000
Reten
tion
Ad
ditive A
pp
lication
Rate (g
/t)
white water solids (g/L)
Headbox Ash (g/L)
Anionic Dispersion MP Application RateTrial Start
Break
Case Study B: Retention (Lab)
Increase in First Pass Ash Retention better than 10+ points
Achieved both at equal and with sheet ash levels at 1% and 2% greater
46.3
57.2 55.857.6
43.4
30.0
35.0
40.0
45.0
50.0
55.0
60.0
65.0
70.0
75.0
80.0
Pre-Trial 22% SheetAsh
Trial 22% SheetAsh
Trial 23% SheetAsh
Trial 24% SheetAsh
Post Trial 22%Sheet Ash
Fir
st
Pa
ss
Re
ten
tio
n/F
irs
t P
as
s A
sh
Re
ten
tio
n (
%)
FPR FPAR
Case Study B: Dusting
Decreased dusting level at equal ash
Dusting propensity did not increase with higher sheet ash load
Sheet ash increment of 2% (24%) at equal dust level as 22% sheet
405.5
315.7
439.3
402.0
0.0
50.0
100.0
150.0
200.0
250.0
300.0
350.0
400.0
450.0
Av
era
ge
Du
st
Le
ve
l (m
g/1
00
00
)
average 22% ashbefore the trial
average 22% ash 450g/t Anionic Dispersion
MP
average 23% ash 625g/t Anionic Dispersion
MP
average 24% ash 800g/t Anionic Dispersion
MP
Case Study B: Defects
ULMA Defects 01 – 02 reduced by 45+%
Lowest defect level achieved at highest ash loading
• Function of transition• 22% data included start-
up• “Cleaning-Up” of wet end
5.5
4.3
3.0 3.0
6.0
0
1
2
3
4
5
6
UL
MA
De
fec
ts 0
1-0
2 (
co
un
t/m
2)
average 22% ashbefore the trial
average 22% ash450 g/t AnionicDispersion MP
average 23% ash625 g/t AnionicDispersion MP
average 24% ash800 g/t AnionicDispersion MP
average 22% ashafter the trial
Mill Case C: Uncoated Free Sheet
Machine Type: Fourdrinier
Objective: Replace existing retention program to improve formation and increase production
Grades: Lt. Wt. Opaque, Offset, Text
Sheet Ash: 12% - 16%
Incumbent Program: Bentonite, Linear C-Pam, Cationic Potato Starch
Other Wet End Chemistry: Alkenyl Succinic Anhydride (ASA) Sizing, Precipitated Calcium Carbonate
Proposed Chemistry: Anionic Dispersion Micropolymer Chemistry, A-Pam, and poly-aluminium 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
Anionic Dispersion MP applied post screen (shear)
A-Pam applied pre-screen (shear)
PAC applied at fan pump (pre A-Pam)
Significant increase in Significant increase in production across majority of production across majority of gradesgrades
• As much as 15+%As much as 15+%
This achieved despite that pre-size press moisture was reduced as much as 0.7%
• Bentonite program pre size press moisture average approximately 1.6%
9.0
9.5
10.0
10.5
11.0
11.5
12.0
12.5
13.0
13.5
14.0
14.5
35# Lt. Wt.Opaque
50# Book 55# Book 40# Offset 60# Offset 60# Copy
Pro
du
ctio
n R
ate
(t/h
r)
C-PAM/Bentonite
A-PAM/Anionic Dispersion MP
+3.8%
+2.1%
+2.8%+5.4%
+5.7%
+15.7%
Mill Case C: Formation
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)
Formation improved across Formation improved across majority of the gradesmajority of the grades
• At least equal
Grades with largest improvement in formation also saw an average of ½ point increase in opacity
• 50#, 55# book• 40# Offset
Grades where equal, generally greatest increase in production
10.0
15.0
20.0
25.0
30.0
35.0
40.0
45.0
50.0
55.0
35# Lt. Wt.Opaque
50# Book 55# Book 40# Offset 60# Offset 60# Copy
MK
Fo
rmat
ion
C-PAM/Bentonite
A-PAM/Anionic Dispersion MP
Hig
he
r is
Be
tte
r
Mill Case C: Additive Efficiency
Anionic Dispersion MP applied post screen (shear)
A-Pam applied pre-screen (shear)
PAC applied at fan pump (pre A-Pam)
Significant starch reduction Significant starch reduction across all the gradesacross all the grades
• 1.5 – 3.0 kg/t• No loss in retention• FPAR as high as 80% on some
grades
Quality not compromised
Sizing response equal or better at equivalent or lower ASA application rate
2.0
3.0
4.0
5.0
6.0
7.0
8.0
9.0
10.0
11.0
12.0
35# Lt. Wt.Opaque
50# Book 55# Book 40# Offset 60# Offset 60# Copy
Sta
rch
Usa
ge
(kg
/t)
C-PAM/Bentonite
A-PAM/Anionic Dispersion MP
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