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Pulp Uniformity Measurement of Single Fiber Properties.
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Transcript of Pulp Uniformity Measurement of Single Fiber Properties.
Pulp UniformityPulp Uniformity
Measurement of SingleMeasurement of Single Fiber Properties Fiber Properties
FIVE MILLION PULP FIBERS
A HANDFULL OF PULP IS A LOT OF FIBERS
• The distribution of single fiber properties has a significant affect on the properties and performance of pulp, paper, and absorbent products.
• This is difficult to prove or to take advantage of without single fiber measurements.
AN HYPOTHESIS
Single Fiber PropertiesSingle Fiber Properties
Kappa Length Kink CurlSurface Charge Cell Wall Thickness
Fiber Performance / Pulp Behavior
ObjectivesObjectives
Develop an optical method for Develop an optical method for measuring single fiber chemical measuring single fiber chemical properties such as kappa number and properties such as kappa number and charge. charge.
Build an instrument capable of Build an instrument capable of performing the analysis quickly on performing the analysis quickly on many fibers.many fibers.
Apply instrument to assess pulping Apply instrument to assess pulping uniformity and the relationship between uniformity and the relationship between pulp uniformity and pulp performance.pulp uniformity and pulp performance.
Fluorescent ProbesFluorescent Probes
Fluorescent probes may be used to Fluorescent probes may be used to investigate chemistry of fibers, mammalian investigate chemistry of fibers, mammalian cells, or other small particlescells, or other small particles High signal-to-noiseHigh signal-to-noise Flow cytometry applicationFlow cytometry application
Fluorescence response to substrate Fluorescence response to substrate chemical environmentchemical environment Emission Spectral Shift – Kappa measurementEmission Spectral Shift – Kappa measurement Emission Intensity Shift – Charge measurementEmission Intensity Shift – Charge measurement
Single Fiber Kappa Single Fiber Kappa MeasurementMeasurement
Why pulp kappa uniformity is important ?
Brownstock pulp strength
Bleaching cost
Target kappa limitations
Fiber kappa distribution of a kappa 34.4 softwood pulp
0
5
10
15
20
25
0 10 20 30 40 50 60 70 80 90 100
kappa
% fi
bers
Mean
Acridine Orange Stained Acridine Orange Stained Cellulose FibersCellulose Fibers
Green = 14 kappa Orange = 32 kappa Red = 83 kappa
AO Fluorescence Spectra AO Fluorescence Spectra for Fibers of Different for Fibers of Different
KappasKappas
Change in Acridine Orange Change in Acridine Orange Fluorescence Ratio with Kappa for Fluorescence Ratio with Kappa for
Three Wood SpeciesThree Wood Species
0.00
0.50
1.00
1.50
2.00
2.50
3.00
0 20 40 60 80 100
kappa
Red
/Gre
en R
atio
D. Fir
S. PineEucalyptus
Epi-Illumination Flow Cytometer
0
1
1
2
2
3
3
4
4
5
5
0 10 20 30 40 50 60 70
kappa
Re
d/G
ree
n
Finnish pine,continuous digester
Finnish pine,SuperBatch digester
Southern pine,laboratory cooked, UW
Southern pine,laboratory cooked,IPST
Epi-Illumination Flow Epi-Illumination Flow CytometerCytometer
Fibers in
Fibers out
Light Source
Flow Cell
Condensing lens and Bandpass Filter
Dichroic MirrorsRed CCD
Bandpass Filters
Green CCD
Green Intensity = ###
Red Intensity = ###
Epi-Illumination Flow Cytometer
Instrument OperationInstrument Operation
Sample preparation ~10 minutesSample preparation ~10 minutes Instrument collects images, applies Instrument collects images, applies
image processing algorithms ~ 10 image processing algorithms ~ 10 min.min.
Statistics on 1000 - 2000 fibersStatistics on 1000 - 2000 fibers
Instrument PerformanceInstrument Performance
Evaluation of instrument noiseEvaluation of instrument noise Reproduce fluorescence microscope Reproduce fluorescence microscope
resultsresults Comparison with independent Comparison with independent
methodmethod Kappa distribution measured at IPST Kappa distribution measured at IPST
with a density gradient columnwith a density gradient column
Measurement NoiseMeasurement Noise
Standard fluorescent beads: 6.5% CV
Propagates to +-1 kappa for kappa 30 fiber
R/G Distribution
0
50
100
150
200
250
300
350
0 2 4 6 8
R/G
frequency
Red/Green Fluorescence vs. Kappa
for IPST SamplesR2 = 0.9953
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
0 10 20 30 40 50 60 70
kappa
Red
/Gre
en
IPST Cook 1 (Kappa 64)
0
1
2
3
4
5
6
7
8
9
10
0 20 40 60 80 100
Kappa
% fi
bers
Density GradientPopulation
FKA Population
IPST Cook 7( kappa 33.4)
0
2
4
6
8
10
12
14
0 20 40 60 80 100Kappa
Pe
rce
nt
of
Fib
ers
FKA Population
density gradient
IPST cook 2 (Kappa 50.5)
0
5
10
15
0 25 50 75 100 125 150
Kappa
% fi
bers
Density GradientPopulation
FKA Population
IPST Cook 3, Kappa 23.4
0
5
10
15
20
0 10 20 30 40 50 60
Kappa
Per
cent
of F
iber
s
Density GradientPopulation
FKA Population
Uniformity ofUniformity of Laboratory and Laboratory and
Commercial PulpsCommercial Pulps
typical kappa distribution for softwood pulp
0
5
10
15
20
25
0 10 20 30 40 50 60 70 80 90 100
kappa
% fi
bers
Statistical Representation of Pulp Statistical Representation of Pulp UniformityUniformity
Coefficient of variationCoefficient of variation
(COV)(COV)
gamma onegamma oneGamma one ~ 0
Gamma one= 1.89
( )
( )
standard deviation
Mean Kappa
3
3
( )iX
N
softwood and hardwood pulps
0
5
10
15
20
25
30
35
0 20 40 60 80
kappa
% f
iber
Birch 17.8
Pine 34.4
Softwood and Hardwood Softwood and Hardwood
PulpsPulps HardwoodHardwood
COV ~ 0.3-0.5COV ~ 0.3-0.5 gamma one ~ 0-gamma one ~ 0-
1.01.0
SoftwoodSoftwood COV ~ 0.3-0.7COV ~ 0.3-0.7 gamma one ~ 1.0-gamma one ~ 1.0-
3.03.0
COV=0.41Gamma one =1.89
COV=0.39Gamma one =0.19
Lab-cooked vs. commercial pulp
0
5
10
15
20
25
30
0 10 20 30 40 50 60 70 80 90kappa
% fi
bers
lab cooked 29.5
commercial 31.4
Commercial vs. Laboratory Commercial vs. Laboratory PulpsPulps
COV=0.54
Gamma one= 1.6
COV=0.34Gamma one =1.59
Effect of Chip Thickness on Effect of Chip Thickness on Hardwood PulpsHardwood Pulps
Effect of chip thickness
0
2
4
6
8
10
12
14
16
18
20
0 10 20 30 40 50 60 70 80
Kappa
%fib
ers
kappa 20.0, 2-4 mm
kappa 20.0, 8-10 mm
Effect of Enzyme Effect of Enzyme pretreatment on pretreatment on Hardwood PulpsHardwood Pulps
Effect of Enzyme Pretreatment
0
5
10
15
20
25
0 10 20 30 40 50 60 70
Kappa
% f
iber
s
Control Pulp kappa 20,8-10 mm chips
Enzyme pretreatedKappa 20, 8-10 mmchips
0
5
10
15
20
25
30
35
0 10 20 30 40 50 60 70 80 90 100
kappa
% fi
bers
control, kappa 34.4
pre-steamed , kappa 31.5
high pressure, kappa 31.3
Effect of pre-steaming and Effect of pre-steaming and pressurepressure
COV= 0.27Gamma one =1.42
COV= 0.31Gamma one =1.29
COV= 0.41Gamma one =1.89
Effect of Pulping Effect of Pulping Temperature Temperature
SuperBatch softwood pulpsSuperBatch softwood pulps Cooking temperature: 168Cooking temperature: 168ºC vs. 176 ºCºC vs. 176 ºC
Varied Varied temperature temperature and and time at time at temperaturetemperature to reach target Kappa to reach target Kappa (~20)(~20)
‘‘time to temperature’time to temperature’, and , and chip thickness chip thickness distributiondistribution also varied, but not controlled also varied, but not controlled..
68 samples68 samples were analyzed were analyzed
ResultsResults
Linear regression analysis to investigate Linear regression analysis to investigate correlation between correlation between COVCOV and cooking and cooking variables; variables; temperature,time to temperature,time to temperature,thick chip percentage,thin chip temperature,thick chip percentage,thin chip percentagepercentage
Regression model for all 68 trials
2
2.158 0.015* 0.005*
0.010* 0.012*
0.82
COV temp timeToTemp
thickChip thinChip
R
Linear regression analysis for Linear regression analysis for all 68 trialsall 68 trials
All trialsEffect of
individualVariables
All 0.82 0.82-
All minus temperature 0.12 0.70All minus ‘time to temp’ 0.58 0.24All minus thick chip % 0.67 0.15All minus thin chip % 0.75 0.07
Variables
2R
2iR
Temperature has a major effect on pulp uniformity
Temperature and time to temperature are correlated. Hence, analysis should split into low (~168ºC) and high temperature (~176ºC) groups
Relative effect of individual variables
2
0.346 0.008*
0.013* 0.016*
0.78
COV timeToTemp
thickChip thinCihp
R
Linear regression model,
low temperature (~168ºC) trials Effect of variables at low temperature
2
0.450 0.005*
0.008* 0.013*
0.65
COV timeToTemp
thickChip thinChip
R
Linear regression model,
high temperature (~176ºC) trials Effect of variables at high temperature
Low temperature trialsEffect of individualvariables
All minus time to temp 0.09 0.69All minus thick chip % 0.31 0.47All minus thin chip % 0.56 0.22
0.78- VariablesAll 0.78
2R
2iR
High temperature trialsEffect of individualvariables
All minus time to temp 0.32 0.33All minus thick chip % 0.5 0.16All minus thin chip % 0.51 0.14
0.65- VariablesAll 0.65 2
iR2
iR
2R
Effect of temperature and ‘time to temperature’
Effect of temperature
0
5
10
15
20
25
30
35
40
0 10 20 30 40 50 60 70
kappa
% fi
bers
high temperature,19.3 kappa
low temperature,19.3 kappa
Effect of 'time to temperature'
0
5
10
15
20
25
30
35
40
0 10 20 30 40 50 60 70
kappa
%fib
ers
shorter time to temp.,kappa 20.2
longer time to temp.,kappa 20.5
COV=0.45
COV=0.55
COV=0.48
COV=0.54
Pulp uniformity from different digesters
0
10
20
30
40
50
0 10 20 30 40 50 60 70 80
Kappa Number
% F
iber
s
Continuousdigester, kappa19.0
SuperBatchdigester, kappa19.3
Single Fiber Charge Single Fiber Charge MeasurementMeasurement
Why is Fiber Charge Why is Fiber Charge Important?Important?
Charge facilitates retaining Charge facilitates retaining papermaking additives and finespapermaking additives and fines Better economicsBetter economics Lower environmental impactLower environmental impact
Charge has a profound effect on Charge has a profound effect on paper formationpaper formation Poor formation leads to poor appearancePoor formation leads to poor appearance Uneven distribution of papermaking Uneven distribution of papermaking
materials affects function (printing, materials affects function (printing, absorbency, etc.)absorbency, etc.)
Drainage on papermachineDrainage on papermachine
Monitoring and Controlling Monitoring and Controlling ChargeCharge
Bulk Solution MeasurementsBulk Solution Measurements Titration techniques with cationic chemicalsTitration techniques with cationic chemicals
Assume uniform charge between particlesAssume uniform charge between particles Electrokinetic MethodsElectrokinetic Methods
Differences in charge between single Differences in charge between single particlesparticles
Many assumptions:Many assumptions: Electrophoresis:Electrophoresis: fines only; spherical particles; fines only; spherical particles;
etc.etc. Electro Kinetic Analyzer (EKA):Electro Kinetic Analyzer (EKA): bulk solution bulk solution Poor correlation with bulk titration resultsPoor correlation with bulk titration results
Stain SelectionStain Selection
Charge-Sensitive Cationic StainCharge-Sensitive Cationic Stain
Charge-Sensitive StainsCharge-Sensitive Stains
Peak Intensites For EB, MEQ, and MQAE Stained Fibers
10.66.4
2830
960
5.6
1
10
100
1000
10000
0.03 0.29
Mean Fiber Charge, meq/g
Pea
k E
mis
sio
n In
ten
sity
, [L
og
] %
Ethidium Bromide
MEQ
MQAE
Stain SelectionStain Selection
Charge-Sensitive Cationic StainCharge-Sensitive Cationic Stain MQAE (Blue 460nm Emission)MQAE (Blue 460nm Emission)
Charge-Charge-InInsensitive Reference Stainsensitive Reference Stain Acridine Orange (Red 630nm Acridine Orange (Red 630nm
Emission)Emission)
Charge Charge ININ-sensitive Stain-sensitive Stain
MQAE and AO Emissions From Fibers at Two Charge Levels
0
20
40
60
80
100
120
140
160
180
MQAE (460nm) AO (635nm)
Inte
nsi
ty, %
0.03meq/g
0.03meq/g
0.29meq/g
0.29meq/g
MQAE Emission
Without AO 0.29meq/g
HIGH CHARGE FIBERS0.29meq/g
LOW CHARGE FIBERS0.03meq/g
Charge-Sensitive Blue Stain - MQAE NOT Charge-Sensitive Red Stain - AO
CalibrationCalibrationBlue/Red Emission vs. Mean Blue/Red Emission vs. Mean
Fiber ChargeFiber Charge
R2 = 0.99
0
5
10
15
20
25
30
35
40
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4
Charge Titration Method, meq/g
Blu
e/R
ed E
mis
sio
n
Northwest Pulp
Northern Pulp
Epi-Illumination Flow Epi-Illumination Flow CytometerCytometer
Fibers in
Fibers out
Light Source
Flow Cell
Condensing lens and Bandpass Filter
Dichroic MirrorsRed CCD
Bandpass Filters
Green Intensity = ###
Red Intensity = ###
Blue CCD
Charge DistributionCharge Distribution
0
5
10
15
20
25
30
0.0 0.1 0.2 0.3 0.4 0.5
Bound MQAE, mol/g
Per
cen
tag
e o
f F
iber
s, %
0.04 meq/g
0.10 meq/g
0.17 meq/g
0.35 meq/g
Charge, meq/g
0.0 0.10 0.20 0.30 0.40 0.50 0.60
Commercial Fiber Commercial Fiber AnalyzerAnalyzer