Evaluation of ECF Bleached SW Kraft Pulps From Mature and ... TAPPI.pdf · Evaluation of ECF Bleached SW Kraft Pulps From Mature and Thinning Softwood Resources A.J. Ragauskas, B.R.

Evaluation of ECF Bleached SW Kraft Pulps From Mature and

Thinning Softwood Resources

A.J. Ragauskas, B.R. Carter, C.C. Courchene, D.H. KimInstitute of Paper Science and Technology, Georgia Institute of Technology

Evaluation of ECF Bleached SW Kraft Pulps From Mature and Thinning Softwood Resources: Background

• Georgia has the highest collection of non-industrial private forest landowners (NIPF) in the nation

• NIPF are a primary source of wood for many of Georgia’s pulp mills.

• NIPF owners have begun to utilize short-rotation management options to improve the feasibility, profitability, and cash flow of production forestry enterprises.

• A valuable component in forestry management approaches is to cutimmature trees to stimulate growth/yield of the remaining trees

• University of Georgia have demonstrated that thinning loblolly and slash pine stands increased internal rate of return for NIPF landowners by 1½% (slash) to 2% (loblolly) over unthinned stands.

• Hence economical factors will increase the availability of pine thinnings for kraft pulping operations

• Potential cost savings of 15 – 30%


The physical performance of kraft pulps bleached/unbleached from thinnings vs. mature wood remains an issue of practical importance

• Zobel, McGovern, and Koch documented (1970 - 81) that southern softwoods from fast-grown plantations are different from that from older, natural stands of the same species because of age, tree form and quality

• Hatton et al. (1996) demonstrated that kraft pulps prepared from black, Norway, red and white spruce thinnings exhibited reduced tear properties, but excellent tensile properties which were attributed to the thinner cell walls from the juvenile wood.

• Drost et al. reported (2004) on variations in fiber characteristics from mature and juvenile wood from whole-log and sawmill chips pulps from juvenile wood had superior beatability resulting from their lower coarseness, while pulps from mature wood exhibited higher tear as a result of their greater fiber lengths.

Evaluation of ECF Bleached SW Kraft Pulps From Mature and Thinning Softwood Resources: Program Objectives

Assess the impact of SW thinnings for the production of bleached kraft pulp for modern southern SW pulp mill operations.

Year 1: Examined SW kraft pulpsYear 2: Examined ECF SW kraft pulps

Evaluation of ECF Bleached SW Kraft Pulps From Mature and Thinning Softwood Resources: Research ObjectivesExperimental:

• Kraft Cooking Process Ratio of Thinnings:Mature Wood Employed• Conventional batch 100:0, 80:20, 40:60, 0:100• Simulated ITC 100:0, 60:40, 0:100

The kraft pulps will be bleached to TAPPI brightness ~85 via two bleaching sequences:OD(E+P+O)DD(E+P+O)DED

• The partially bleached pulps will be analyzed for kappa number, viscosity, and TAPPI brightness

• The fully bleached pulps will be analyzed for optical, chemical, and physical strength properties

• Fully bleached pulps will also be PFI refined with 2000, and 4,000 revs and the physical strength properties will be re-assessed at each point of refining

Evaluation of ECF Bleached SW Kraft Pulps From Mature and Thinning Softwood Resources: Wood Results

Wood Chips Properties for Thinning vs. Mature

Density Klason Lignin Extractives Earlywood:LatewoodThinning 0.423 29.8 2.77 1.0:0.89Mature 0.448 28.5 1.93 1.0:1.53

Carbohydrate Profile (%)

Gluc. Galact. Mann. Xylan. Arabinan

Thinning 64.9 4.5 16.9 10.6 3.1

Mature 67.9 3.5 17.7 8.8 2.1

Evaluation of ECF Bleached SW Kraft Pulps From Mature and Thinning Softwood Resources: Pulping Results

Thinning (T)Mature (M)

80:20 T/M60:40 T/M

40:60 T/M

Screened Yield

Total Yield4444.244.444.644.8

4545.2

45.4

45.6

45.8

46

Pulp

Yie

lds

Total and Screened Yields for Conventional Kraft Pulping

1,43340:60

1,43460:40

1,43880:20

1,4450:100

1,436100:0Conventional Kraft

Final H-factor

SW ChipsThinning:

Mature

Cook Type

16

18

20

22

24

26

28

Kap

pa #

Thinning (T) Mature (M) 80:20 T/M 60:40 T/M 40:60 T/M

Kappa # for Conventional Kraft Pulps

`

Evaluation of ECF Bleached SW Kraft Pulps From Mature and Thinning Softwood Resources: Pulping Results


1 00 % T hin.10 0% Mature

60 :40 T hin/Mat

K app a #

S cree ne d Yie ld %0

5

10

15

20

25

30

35

40

45

50

K app a #S c re ene d Yie ld %

1,70960:40

1,7130:100

1,717100:0Modified Continuous Kraft

Final H-factor

SW Chips

Thinning: Mature

Cook Type

Kappa Number for Lab-Simulated Continuous Kraft Cook

171186086.816.660:40 (T:M)174117073.219.9100% Mature (M)164187085.415.6100% Thinning (T)

Modified continuous Kraft172186290.115.740:60 (T:M)173170788.714.460:40 (T:M)164196892.214.680:20 (T:M)174174888.216.8100% Mature (M)163209891.113.6100% Thinning (T)

Conventional Kraft

Zero-Span Tensile Index

(N/mm)

TEA(J/m2)

Tensile Index

(N/mm)

Tear Index(mNm2/g)

Evaluation of ECF Bleached SW Kraft Pulps From Mature and Thinning Softwood Resources: Pulp Results

Evaluation of ECF Bleached SW Kraft Pulps From Mature and Thinning Softwood Resources: Experimental Protocol

OD(E+P+O)D O-Stage (Incoming brownstock kappa # 24-27)

– 60 min, 100oC, 10% csc, 90 psig O2– Caustic charge varied 1.0 – 1.8

• preferred value ~1.5% NaOH to yield post-O kraft pulps with kappa # ~ 10

• Do-Stage• 45 min, 50oC, 3.5% csc, Kf 0.25, terminal pH 2.1 – 2.3

• (E+P+O)-Stage • 60 min, 75oC, 10% csc, 0.4% H2O2, initial O2:65 psig 15 min; then vent12 psig/5 min, %NaOH

50% of Kf

• D1-Stage• 180 min, 75oC, 10% csc, ClO2 charge 0.5 – 2.0%, terminal pH 3

• Final TAPPI Brightness Values ~ 87

Evaluation of ECF Bleached SW Kraft Pulps From Mature and Thinning Softwood Resources: Bleaching Results

OD(E+P+O)D TAPPI Brightness Properties

Conventional ITCMature 87.6 87.2Thinning 87.2 87.560% Thin/40% Mature 87.440% Thin/60% Mature 87.380% Thin/20% Mature 87.7


OD(E+P+O)D Fiber Properties: Fiber Length

Mature 60%Thinning Thinning

Length Weighted

Weight Weighted0.00

1.00

2.00

3.00

4.00

FQA

Len

gth

(mm

)ITC


OD(E+P+O)D Fiber Properties: Fiber Length

Thinning

40% Thin

80% Thin

.Matu

re

Length WeightedWeight Weighted0.00

0.501.001.502.002.503.003.504.00

FQA

Len

gth

(mm

)

Conventional


OD(E+P+O)D Fiber Properties: Fines

0.0

2.0

4.0

6.0

8.0

10.0

% F

ines

(Arit

hem

etic

)

ITC:Mature ITC: 60%Thinning

ITC:Thinning

Thinning 40% Thin 80% Thin. Mature


OD(E+P+O)D Fiber Properties: Fiber Charge

0.0000

0.0050

0.0100

0.0150

0.0200

0.0250

0.0300

ITC:Mature ITC: 60%Thinning

ITC:Thinning

Thinning 40% Thin 80% Thin. Mature

mm

ol A

cid

goup

/gr p

ulp


OD(E+P+O)D Sheet Properties

ITC:MatureITC 60% T

ITC: Thin

0

2000

4000

0

10

20

30

40

50

60

70

Tens

ile In

dex

(Nm

/g)

Revolutions1

23

ITC:Mature

ITC 60% T

ITC: Thin

0

2

4

6

8

10

12

14

Tear

Inde

x (m

Nm

2/g)

02000

4000


Sheet Properties: Conventional Kraft Pulps

Thin80% T

40% TMature

O Revs

2000 revs

4000 revs

0

10

20

30

40

50

60

70

80

Tens

ile In

dex



Thin80% T

40% TMature

O Revs

2000 Revs

4000 Revs

0

500

1000

1500

2000

2500

TEA

Inde

x



12

3

Thin

80% T

40% T

Mature

0

2

4

6

8

10

12

14

16

Tear

Inde

x

02000

4000

Evaluation of ECF Bleached SW Kraft Pulps From Mature and Thinning Softwood Resources: Experimental Protocol

D(E+P+O)DED• D-Stage (Incoming brownstock kappa # 24-27)

– K.f.:0.20, 45 min, 50oC, 3.5% csc, terminal pH: 1.8 • (E+P+O)-Stage

• 60 min, 90oC, 10% csc, 0.4% H2O2, initial O2:35 psig 15 min; then vent 12 psig/5 min, 3.2 %NaOH

• D1-Stage• 180 min, 75oC, 10% csc, 1.0% ClO2, terminal pH 3

• E-Stage• 60 min, 75oC, 10% csc, 0.5% NaOH, terminal pH 12

• D1-Stage• 180 min, 75oC, 10% csc, 0.2% ClO2, terminal pH 3

• Final TAPPI Brightness Values ~ 88


D(E+P+O)DED TAPPI Brightness Properties

Conventional ITCMature 87.8 88.1Thinning 87.8 88.960% Thin/40% Mature 88.4 88.340% Thin/60% Mature 88.380% Thin/20% Mature 88.4


Pulp Viscosity Properties (mPa.s)Conventional D(EPO)DED ITC D(EPO)DED

Mature 18.7 33.0Thinning 23.0 21.360% Thin/40% Mature 22.1 24.740% Thin/60% Mature 21.680% Thin/20% Mature 23.1

Physical Strength Properties Evaluated After 0, 2000, and 4000 revs PFI refining


D(E+P+O)DED Fiber Properties: Fiber Length

100%

Thinnin

g10

0% M

ature

80% Thin

ning/2

0% M

ature

60% Thin

ning/4

0% M

ature

40% Thin

ning/6

0% M

ature

100%

Thinnin

g-ITC C

ooks

100%

Matu

re-ITC C

ooks

Blend o

f Matu

re:Thin

ning-I

TC Coo

ks

Length-WeightedWeight-Weighted

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

4.50

FQA

Fib

er L

engt

h/m

m

ITC Pulps


D(E+P+O)DED Fiber Properties: Tensile Index

100%

Thinnin

g

1. 0

revs

.

2

. 2,00

0revs

.

3

. 4,00

0revs

.

100%

-Matu

re

4. 0

revs

.

5

. 2,00

0revs

.

6

. 4,00

0revs

.

80% Th

inning

/20% M

ature

7

. 0 re

vs.

8

. 2,00

0revs

.

9

. 4,00

0revs

.

60% Th

inning

/40% M

ature

10

. 0 re

vs.

11

. 2,00

0revs

.

12

. 4,00

0revs

.

40% Th

inning

/60% M

ature

1

3. 0 r

evs.

1

4. 2,0

00rev

s.

1

5. 4,0

00rev

s.

100%

Thinnin

g-ITC

1

6. 0 r

evs.

17

. 2,00

0revs

.

18

. 4,00

0revs

.

100%

Matu

re-ITC

1

6. 0 r

evs.

17

. 2,00

0revs

.

18

. 4,00

0revs

.

60% Th

in/40

% Matu

re ITC

1

9. 0 r

evs.

2

0. 2,0

00rev

s.

2

1. 4,0

00rev

s.

0

10

20

30

40

50

60

70

80

90

100

Tens

ile In

dex

ITC Pulps

100% T 100% M 60% T 100% T 100% M 60% T

Optimizing the Bleaching of Georgia’s SW Thinning Wood Resource: ResultsD(E+P+O)DED Fiber Properties: Burst Index

0

1

2

3

4

5

6

7

8

Bur

st In

dex

100%

Thinnin

g

1. 0

revs

.

2

. 2,00

0revs

.

3

. 4,00

0revs

.10

0%-M

ature

4

. 0 re

vs.

5

. 2,00

0revs

.

6

. 4,00

0revs

.

80% Thin

ning/2

0% M

ature

7

. 0 re

vs.

8

. 2,00

0revs

.

9

. 4,00

0revs

.

60% Thin

ning/4

0% M

ature

10

. 0 re

vs.

11

. 2,00

0revs

.

12

. 4,00

0revs

.

40% Thin

ning/6

0% M

ature

1

3. 0 r

evs.

1

4. 2,0

00rev

s.

1

5. 4,0

00rev

s.

100%

Thinnin

g-ITC

1

6. 0 r

evs.

17

. 2,00

0revs

.

18

. 4,00

0revs

.

100%

Matu

re-ITC

1

6. 0 r

evs.

17

. 2,00

0revs

.

18

. 4,00

0revs

.

60% Thin

/40% M

ature

ITC

19.

0 rev

s.

2

0. 2,0

00rev

s.

2

1. 4,0

00rev

s.

ITC Pulps

100% T 100% M 80% T 60% T 40%T 100% T 100% M 60% T

Optimizing the Bleaching of Georgia’s SW Thinning Wood Resource: ResultsD(E+P+O)DED Fiber Properties: Tear Index

0

5

10

15

20

25

Tear

Inde

x

100%

Thinnin

g

1. 0

revs

.

2

. 2,00

0revs

.

3

. 4,00

0revs

.10

0%-M

ature

4

. 0 re

vs.

5

. 2,00

0revs

.

6

. 4,00

0revs

.

80% Thin

ning/2

0% M

ature

7

. 0 re

vs.

8

. 2,00

0revs

.

9

. 4,00

0revs

.

60% Thin

ning/4

0% M

ature

10

. 0 re

vs.

11

. 2,00

0revs

.

12

. 4,00

0revs

.

40% Thin

ning/6

0% M

ature

1

3. 0 r

evs.

1

4. 2,0

00rev

s.

1

5. 4,0

00rev

s.

100%

Thinnin

g-ITC

1

6. 0 r

evs.

17

. 2,00

0revs

.

18

. 4,00

0revs

.

100%

Matu

re-ITC

1

6. 0 r

evs.

17

. 2,00

0revs

.

18

. 4,00

0revs

.

60% Thin

/40% M

ature

ITC

19.

0 rev

s.

2

0. 2,0

00rev

s.

2

1. 4,0

00rev

s.

ITC Pulps

100% T 100% M 100% T 100% M 60% T

Optimizing the Bleaching of Georgia’s SW Thinning Wood Resource: ResultsD(E+P+O)DED Fiber Properties: Dry Zero Span

0

20

40

60

80

100

120

140

160

180

Dry

Zer

o Sp

an

100%

Thinnin

g

1. 0

revs

.

2

. 2,00

0revs

.

3

. 4,00

0revs

.10

0%-M

ature

4

. 0 re

vs.

5

. 2,00

0revs

.

6

. 4,00

0revs

.

80% Thin

ning/2

0% M

ature

7

. 0 re

vs.

8

. 2,00

0revs

.

9

. 4,00

0revs

.

60% Thin

ning/4

0% M

ature

10

. 0 re

vs.

11

. 2,00

0revs

.

12

. 4,00

0revs

.

40% Thin

ning/6

0% M

ature

1

3. 0 r

evs.

1

4. 2,0

00rev

s.

1

5. 4,0

00rev

s.

100%

Thinnin

g-ITC

1

6. 0 r

evs.

17

. 2,00

0revs

.

18

. 4,00

0revs

.

100%

Matu

re-ITC

1

6. 0 r

evs.

17

. 2,00

0revs

.

18

. 4,00

0revs

.

60% Thin

/40% M

ature

ITC

19.

0 rev

s.

2

0. 2,0

00rev

s.

2

1. 4,0

00rev

s.

ITC Pulps

100% T 100% M 100% T 100% M 60% T

Optimizing the Bleaching of Georgia’s SW Thinning Wood Resource: ResultsD(E+P+O)DED Fiber Properties: Wet Zero Span

0

20

40

60

80

100

120

140

160

Wet

Zer

o Sp

an

100%

Thinnin

g

1. 0

revs

.

2

. 2,00

0revs

.

3

. 4,00

0revs

.10

0%-M

ature

4

. 0 re

vs.

5

. 2,00

0revs

.

6

. 4,00

0revs

.

80% Thin

ning/2

0% M

ature

7

. 0 re

vs.

8

. 2,00

0revs

.

9

. 4,00

0revs

.

60% Thin

ning/4

0% M

ature

10

. 0 re

vs.

11

. 2,00

0revs

.

12

. 4,00

0revs

.

40% Thin

ning/6

0% M

ature

1

3. 0 r

evs.

1

4. 2,0

00rev

s.

1

5. 4,0

00rev

s.

100%

Thinnin

g-ITC

1

6. 0 r

evs.

17

. 2,00

0revs

.

18

. 4,00

0revs

.

100%

Matu

re-ITC

1

6. 0 r

evs.

17

. 2,00

0revs

.

18

. 4,00

0revs

.

60% Thin

/40% M

ature

ITC

19.

0 rev

s.

2

0. 2,0

00rev

s.

2

1. 4,0

00rev

s.

ITC Pulps

100% T 100% M 100% T 100% M 60% T

Evaluation of ECF Bleached SW Kraft Pulps From Mature and Thinning Softwood Resources: Bleaching ResultsConclusions:

• Observe differences in Thin. vs. Mature wood and kraft pulp samples are maintained in fully bleached pulps

• Trends observed for conventional kraft pulps observed in continuous kraft

• Differences in tensile vs. tear less than some northern species

Evaluation of ECF Bleached SW Kraft Pulps From Mature and Thinning Softwood Resources: Bleaching ResultsConclusions:

•Experimental results between 40:60 and 60:40 blends of Thinning and Mature are very small and would most likely not be observed in commercial practice

•Depending on product grade thinnings will provide distinct cost saving with little impact on product performance

Evaluation of ECF Bleached SW Kraft Pulps From Mature and Thinning Softwood Resources

AcknowledgementsGA TIP3

Mill Personnel From Georgia Pacific

International PaperWeyerhaeuser

Rayonier

Evaluation of ECF Bleached SW Kraft Pulps From Mature and ... TAPPI.pdf · Evaluation of ECF Bleached SW Kraft Pulps From Mature and Thinning Softwood Resources A.J. Ragauskas, B.R.

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