Extraction Stages
Transcript of Extraction Stages
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Fundamentals of Extraction StagesFundamentals of Extraction Stagesfor Kraft Pulps Bleachingfor Kraft Pulps Bleaching
Brian N. Brogdon, Ph.D.Brian N. Brogdon, Ph.D.
Senior Research ScientistSenior Research Scientist
Kemira Chemicals, Inc.
1525 Church St. Extension
Marietta, GA 30060-1023 USA
Kemira Chemicals, Inc.
1525 Church St. Extension
Marietta, GA 30060-1023 USA
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Alkali ExtractionAlkali Extraction ---- E or (EO) or (EOP)E or (EO) or (EOP)PurposePurpose
Solubilize & Disperse oxidized lignin fragments in alkali fromprevious acid oxidation stage
Remove solubilized lignin from the pulp fiber (i.e., washing)
Re-Activate residual lignin in the fiber toward furtheroxidation/modification
Few studies have focused on extraction since the shift fromFew studies have focused on extraction since the shift from
Chlorine (C or CChlorine (C or CDD or (DC)) to Chlorine Dioxide (Dor (DC)) to Chlorine Dioxide (D00))Extraction is often taken for granted as an integrated extensionExtraction is often taken for granted as an integrated extension
of the previous oxidation stageof the previous oxidation stage
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Reactions of Chlorine Dioxide during D0 Stage
[Brogdon, Mancosky & Lucia, IPBC 2002]
(II)
R
O
OR1
+ CH3OH
o
-Quinone
Primary Blocking GroupPrimary Blocking Group
R
HOOR1
OCH3
O
Muconic Acid Ester
(I)
Improved Lignin SolubilityImproved Lignin Solubility
R
OH
OCH3R1
+ ClO2
Phenolic Group
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Reactions with Alkali During Extraction[Brogdon, Mancosky & Lucia, IPBC 2002]
R
HO
OR1
OCH3
OMuconic Acid Ester
HO
R
HO
OR1
OH
OMuconic Acid Structure
+ CH3OH
Alkali causes saponification and improves lignin solubility
Does not make Muconic Structure more reactive towards ClO2 againR
O
OR1
o
-Quinone
R
OH
OHR1
Polyphenol
HO
HO
Alkali transforms quinones to structures more reactive towards ClO2
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Alkali Reactions with Chlorolignin Compounds
Partially Dechlorinated
Cpd.
+ Cl
R
OCH3
OCH3Cl
Cl OH
R
OCH3
OCH3Cl
+ HO
Chlorinated Organic
Cl Cl
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Process Variables for Extraction Stages
Caustic Charge and Previous Oxidation Stage Conditions
Time and TemperatureTime and Temperature
Consistency
Influence of Oxidative Reinforcement
Oxygen (EO)
Pressure
Time at Pressure
Oxygen and Peroxide (EOP)
Examples Taken from R. Berrys 1999 TAPPI Bleaching Short Course
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Impact of Caustic Charge on C Stage PulpImpact of Caustic Charge on C Stage Pulp
Sufficient NaOH is applied in the E Stage to achieve an end pH ~Sufficient NaOH is applied in the E Stage to achieve an end pH ~
10 to 11 (helps to ionize and disperse lignin fragments)10 to 11 (helps to ionize and disperse lignin fragments)
Low end pH (
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Impact of C Stage Charge (Kappa Factor) on ExtractioImpact of C Stage Charge (Kappa Factor) on Extractio
Decreasing the Kappa Factor results in less Delignification at aDecreasing the Kappa Factor results in less Delignification at a
given NaOH chargegiven NaOH charge
Higher NaOH Charge is required to achieve same DelignificationHigher NaOH Charge is required to achieve same Delignificationfor lower Kappa Factorfor lower Kappa Factor
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E stage generally requires less NaOH when converting from C or (E stage generally requires less NaOH when converting from C or (DC)DC)
stage to Chlorine Dioxide Delignification (Dstage to Chlorine Dioxide Delignification (D00))
LessLess NaClNaCl is generated with Dis generated with D00 treated pulps due to lesstreated pulps due to less chloroligninchlorolignincompounds vs. C or (DC) Treated Pulpscompounds vs. C or (DC) Treated Pulps
Impact of Shifting from C or (DC) to DImpact of Shifting from C or (DC) to D00
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Effect of Extraction Time and TemperatureEffect of Extraction Time and Temperature
Initial rapid delignification phase that occurs within 10 minuteInitial rapid delignification phase that occurs within 10 minutess
Majority of Delignification is accomplished in 40 to 60 minutesMajority of Delignification is accomplished in 40 to 60 minutes
Operating at higher temperatures increases DelignificationOperating at higher temperatures increases Delignification
im roved diffusion of li nin from inside the fiber(improved diffusion of lignin from inside the fiber)
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Effect of Extraction ConsistencyEffect of Extraction Consistency
Consistency has a minor effect on Delignification or ShrinkageConsistency has a minor effect on Delignification or Shrinkage
Operating at higher consistencies can reduce steamOperating at higher consistencies can reduce steam
requirements for extractionrequirements for extraction
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Extraction Stage with Oxygen and Peroxide
Downflow Tube
(atmospheric)
Downflow TubeDownflow Tube
(atmospheric(atmospheric)
PulpPulpPulp O2 &
H2O2
OO22 &&
HH22OO22
SteamSteamSteam
Stabilizer(s)Stabilizer(s)Stabilizer(s)
PulpPulpPulp
Upflow Tube
(pressurized)
Upflow TubeUpflow Tube
(pressurized)(pressurized)
NaOHNaOHNaOH
f f ( O) SI t f P id f E d (EO) St
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Impact of Peroxide for E and (EO) StagesImpact of Peroxide for E and (EO) Stages
Addition of OAddition of O22 improves E stage Delignificationimproves E stage Delignification
Can reduce the amount of active Cl2 (Kappa Factor) by 20% in
the C or (DC) stage to achieve the same level of Delignification
I t f O R i f d E t ti (EO)I t f O R i f d E t ti (EO)
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Impact of Oxygen Reinforced Extraction (EO)Impact of Oxygen Reinforced Extraction (EO)
Minimum (EO) conditions are 20 psig OMinimum (EO) conditions are 20 psig O22 held at pressure for 3held at pressure for 3
min. (generally achieved withmin. (generally achieved with upflowupflow tower w/ 10 min. retention)tower w/ 10 min. retention)
Addition of OAddition of O22 under typical (EO) conditions has a negligibleunder typical (EO) conditions has a negligibleeffect on Pulp Viscosity [values in parentheses]effect on Pulp Viscosity [values in parentheses]
I t f P id f E d (EO) StI t f P id f E d (EO) St
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Impact of Peroxide for E and (EO) StagesImpact of Peroxide for E and (EO) Stages
Addition of peroxide improves E and (EO) DelignificationAddition of peroxide improves E and (EO) Delignification
Can reduce the amount of active Cl2 (Kappa Factor) from 20 to
40% in the C or (DC) stage to achieve the same level ofDelignification
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62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90 1.00
Effect of Peroxide Charge on (EOP) Brightness Developmen
Initial D0 Pulp Brightness = 53.1
ISO
Brigh
tness(%)
% H2O2 in (EOP)
~70% Increasein Post-
Extraction
Brightness vs.(EO)
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Improving (EOP) Bleaching Efficiency
Metals management is important for maximizing (EOP)bleaching efficiency
Current shift in C or (DC) to DCurrent shift in C or (DC) to D00 DelignificationDelignification
pH in D0 stages are higher than C or (DC) stages (2.5 - 4 vs.
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(EOP) Bleaching Enhancement of D(EOP) Bleaching Enhancement of D00(EOP)D(EOP)DNND SequenceD SequenceNorthern Hardwood Kraft Pulp (10Northern Hardwood Kraft Pulp (10--12 Kappa) to 88 ISO Brightness12 Kappa) to 88 ISO Brightness
Metals Profile of D0Pulp
Metal Ions ppm on PulpCa 130
Mg 95
Fe 27
Mn ND
Cu 8.8
(EOP) Bleaching Conditions:(EOP) Bleaching Conditions:
0.60% H2O2
2.5 % NaOH
12% Consistency
Pressurization w/ O2
Upflow - 20 min. at 0.21 MPa
(30 psig) and 77C (170F)Downflow - 40 min. at 0 MPa
(0 psig) and 77C (170F)
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(EOP) Bleach Stabilizers Examined(EOP) Bleach Stabilizers Examined
AminocarboxylateAminocarboxylate--Based (ACBased (AC--Based) StabilizersBased) Stabilizers(0.10(0.10 -- 0.15% on pulp)0.15% on pulp)
Stabilizer BStabilizer E (MgSO4 replacement)
Organophosphonate-Based (OP-Based) Stabilizers (0.10% on pulp)(0.10% on pulp)
Stabilizer D
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(EOP) Brightness Development (Lab)
Initial D0 Pulp Brightness = 53.1
69
70
71
72
73
74
75
Control
B(0.10%
)
D(0.10%
)
E(0.15%
)
ISO
Brightness(
%)
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62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90 1.00
(EOP) Brightness Development with Peroxide Dosage (Lab)
Initial D0 Pulp Brightness = 53.1
ISO
Brigh
tness(%
)
% H2O2 in (EOP)
Stabilizer E (0.15%)
Control (no additive)
D B i ht D l t ith ClO D (L b)
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80
81
82
83
84
85
86
87
88
89
90
0.00 0.25 0.50 0.75 1.00 1.25 1.50 1.75 2.00
D1 Brightness Development with ClO2 Dosage (Lab)
for Various (EOP) Treatments
ISO
Brigh
tness(%
)
% ClO2 in D1
Stabilizer E (0.15%) in (EOP)Stabilizer E (0.15%) in (EOP)
Control (no additive)Control (no additive)
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(EOP) Mill Trial of Bleach Stabilizer E
61.062.063.064.065.066.067.068.069.070.0
71.072.0
0 10 20 30 40 50 60 70 80 90 100 110
Control (no additive) Stabilizer E (0.10%)
ISOB
rightness
Observations
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Summary of Mill Trial (EOP) Bleaching Enhancement
Addition of Stabilizer E to the (EOP) stage
Increased (EOP) brightness from 64.3 to 68.1 (~ 4 point gain)
Mill was able to reduce D0 kappa factor from 0.21 to 0.17
Preliminary results showed an overall ClO2 reduction ofD0(EOP)DND by 4 to 5 lb/ton pulp
Able to maintain 88 ISO brightness target
Trial is on-going and continuing to optimize conditions
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(EOP) Bleaching Enhancement of D(EOP) Bleaching Enhancement of D00(EOP)D(EOP)DNND SequenceD SequenceSouthern Softwood Kraft Pulp (~32 Kappa) to 85 ISO BrightnessSouthern Softwood Kraft Pulp (~32 Kappa) to 85 ISO Brightness
Bleaching Conditions:Bleaching Conditions:
0.60% H2O2
2.25 % NaOH
12% Consistency
Pressurization w/ O2
Upflow - 10 min. at 0.21 MPa
(30 psig) and 75C (166F)Downflow - 35 min. at 0 MPa
(0 psig) and 75C (166F)
Metals Profile of D0PulpMetal Ions ppm on Pulp
Ca 80
Mg 40Fe 90
Mn ND
Cu ND
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(EOP) Brightness Development (Lab)
Initial D0 Pulp Brightness = 40.0
57
58
59
60
61
62
63
Contro
l
E(0.15
%)
ISO
Brigh
tness(%
)
D Brightness Development with ClO Dosage (Lab)
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78
79
80
81
82
83
84
0.40 0.50 0.60 0.70 0.80 0.90 1.00 1.10 1.20 1.30 1.40 1.50
D1 Brightness Development with ClO2 Dosage (Lab)
for Various (EOP) Treatments
I
SO
Brigh
tness(%
)
% ClO2 in D1
Stabilizer E (0.15%) in (EOP)Stabilizer E (0.15%) in (EOP)
Control (no additive)Control (no additive)
7 to 8 lb/T ClO2Reduction
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Questions?
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TAPPIs Antitrust Policy Statement
The Technical Association of the Pulp and Paper
Industry (TAPPI) is a professional and scientificassociation organized to further the applications of the
sciences in the pulp and paper industry. Its aim is to
promote research and education in the sciences andpractices of pulp and paper manufacture. TAPPI is
not intended to, and may not, play any role in the
competitive decisions of its members or their
employers, or in any way restrict competition in the
pulp and paper industry.
TAPPIs Antitrust Policy Statement
The Technical Association of the Pulp and Paper
Industry (TAPPI) is a professional and scientificassociation organized to further the applications of the
sciences in the pulp and paper industry. Its aim is to
promote research and education in the sciences andpractices of pulp and paper manufacture. TAPPI is
not intended to, and may not, play any role in the
competitive decisions of its members or their
employers, or in any way restrict competition in the
pulp and paper industry.