Extraction Stages

7/25/2019 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)


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)


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)


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.

Documents

Extraction Stages