Effects of Final Bleaching Stage Using Hydrogen Peroxide and Peracetic Acid (eq.) in the ECF

Bleaching of Acacia D0EOPD1 Kraft Pulps

Presenter : Dede Ermawan (st110031)Adviser : Dr. Jiri Basta (Chairman)

Dr. Mousa M. Nazhad Dr. Esa Lehtinen

Presented on Master Theses Competetion, AIT, 16th May 2011

INTRODUCTION

Background

Problem •Typically ECF Bleaching O-D0-EOP-D1-D2•The high chemical charge result in high cost and high environmental load.

Proposal •Looking for chemical to reduce chemical consumption which more effective in final bleaching and less environmental load

Objectives•To optimize the existing process and reintroduce new agents to minimize the cost and environmental load•To optimize D2 stage•To examine new chemicals (P and PAA)

EXPERIMENTAL DESIGN

Experimental Plan

RESULTS

D1 Stage Optimization

0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.075.0

77.0

79.0

81.0

83.0

85.0

87.0

89.0

91.0

D1 Experiments

D1 Experiment Target 85% Target 87% Target 89%

Chlorine Dioxide as active cholrine (% On Pulp)

Bri

gh

tne

ss

(%

ISO

)

D1 stage: T=70°C, t=150 min, Consistency=10%, end pH= 3.5-4.5

A PulpB Pulp

C Pulp

D2 Stage Results

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.080

82

84

86

88

90

92

94

Chlorine Dioxide (D2) Experiments

A Pulp B Pulp C Pulp Target

Chlorine Dioxide as active chlorine (% on pulp)

Bri

gh

tne

ss

(%

ISO

)

D2 stage: T=70°C, t=180 min, Consistency=10%, end pH= 4.0-4.5

P Stage Results

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.00

102030405060708090

100

Final P Experiments

A Pulp B Pulp C Pulp Target

Hydrogen Peroxide Charge (% on Pulp)

Bri

gh

tne

ss

(%

ISO

)

P stage: T=90°C, t=90 min, Consistency=10%, Mg= 0.05%, end pH= 11-12

PAA Stage Results

0.00 0.10 0.20 0.30 0.40 0.500

102030405060708090

100Final Paa Experiments

A Pulp B Pulp C PulpA Pulp Change pH 11-12 B pulp Change pH 11-12 C Pulp Change pH 11-12Target 90% Brightness

Peracetic acid Charge (% on Pulp)

Brig

htne

ss (%

ISO

)

PAA stage: T=80°C, t=90 min, Consistency=10%, end pH= 5-6PAA/P stage: additonal: T=80°C, t=90 min, Consistency=10%, end pH= 11-12

Evaluation

Pulp Quality

CostEnvironmental

Brightness Reversion

90.6

90.0 90.2 90.2 90.0 90.1 90.0 90.1 90.1 90.1

88.8

87.688.1 88.0

88.7 88.588.9 89.0 88.8

88.6

-2.04-2.67

-2.38 -2.48

-1.51 -1.69-1.29 -1.25 -1.40 -1.62

-4.00

-2.00

0.00

2.00

4.00

6.00

8.00

10.00

80.0

82.0

84.0

86.0

88.0

90.0

92.0

D2 Mill A Final D B Final D C Final D A Final P B Final P C Final P A Final PAA/P B Final PAA/P B Final PAA

Brightness & Brightness Reversion

Initial Brightness (%ISO) Brightness reversion 105 deg celcius 4h (%ISO) Percentage reversion (%)

% IS

O%

Re

versio

n

Extractive Content

D2 Mill A Final D B Final D C Final D A Final P B Final P C Final P A Final PAA/P

B Final PAA/P

B Final PAA

0.000.050.100.150.200.250.300.350.400.450.50

0.260.31 0.30 0.31

0.09 0.08 0.07 0.05 0.050.10

Acetone Extractable Matter (%)

Properties of pulps

Kind of Pulps

Fiber Morphology Optical Properties Strength Properties

No. of Fibers

(Mill./g)

Average Length (mm)

Coarseness (mg/m)

Fines Content

(%weight)

Fiber Width (µm)

Opacity s coefficient (m²/kg)

k coefficient

(m²/kg)

Tear Index (mN.m2/g)

Tensile Index

(Nm/g)z-span Nm/g

D2 Mill 29.55 0.630 0.072 3.34 17.45 83.50 55.07 0.16 4.64 22.91 120.0

A Final D 27.23 0.640 0.077 3.29 17.30 83.05 53.69 0.16 5.22 23.88 129.0

B Final D 29.14 0.640 0.072 3.32 17.35 83.46 54.15 0.16 5.06 25.42 132.0

C Final D 28.26 0.635 0.075 3.29 17.35 83.27 54.89 0.16 4.69 24.71 128.0

A Final P 27.96 0.635 0.075 3.15 17.20 82.74 54.43 0.17 5.41 23.59 125.0

B Final P 28.74 0.635 0.073 3.20 17.20 82.75 54.76 0.16 5.40 24.44 130.0

C Final P 29.24 0.635 0.072 3.31 17.30 81.92 51.33 0.17 5.68 24.95 123.0

A Final PAA/P 29.88 0.650 0.069 3.17 ND 82.10 52.34 0.16 5.26 24.20 123.0

B Final PAA/P 28.74 0.640 0.073 3.28 ND 83.01 53.44 0.16 5.74 24.07 123.0

B Final PAA 29.34 0.640 0.071 3.18 ND 83.03 54.38 0.16 4.83 24.13 122.0

Average 28.81 0.638 0.073 3.25 17.31 82.88 53.85 0.16 5.19 24.23 125.5

S. deviation 0.80 0.005 0.002 0.07 0.09 0.53 1.20 0.00 0.39 0.71 4.0

Max 29.88 0.650 0.077 3.34 17.45 83.50 55.07 0.17 5.74 25.42 132.0

Min 27.23 0.630 0.069 3.15 17.20 81.92 51.33 0.16 4.64 22.91 120.0

Evaluation

Pulp Quality

CostEnvironmental

Evaluation of Environmental parameters

0.00 0.20 0.40 0.60 0.80 1.000.00

1.00

2.00

3.00

4.00

5.00

6.00

7.00

8.00

Plot of Bleaching Process vs COD (kg/tp)

Final PAA D1 D2 Final PFinal PAA/P

%Charge Chemical on Pulp

COD

(kg/

tp)

0.00 0.20 0.40 0.60 0.80 1.000.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

Plot of bleaching process vs Suspended Solid (kg/tp)

D1 D2 Final PFinal PAA/P Final PAA

Charge of Chemical (% on Pulp)

Susp

ende

d So

lid (k

g/tp

)

0.25 0.90 0.40 0.10D1 D2 Final P Final

PAA/P

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.70

0.80

Chloride content (kg/tp) in Bleaching filtrate

BAT emission of Bleached kraft pulp:

Evaluation

Pulp Quality

CostEnvironmental

Cost Analysis

No Process

D1 Final D Final Bleaching

Cost Per tp (USD)

*6000 tp per day (USD)aCl (kg/tp) NaOH

(kg/tp) aCl (kg/tp) NaOH (kg/tp)

1 A Final D 1.5 0 10.0 0.5 4.950 29,6992 B Final D 2.5 0 9.0 0.5 4.950 29,6993 C Final D 9.0 0.5 1.5 0 4.532 27,190

No Process

D1 Final P Final Bleaching

Cost Per tp (USD)

*6000 tp per day (USD)aCl (kg/tp) NaOH

(kg/tp)Hydrogen peroxide (kg/tp)

NaOH (kg/tp)

1 A Final P 1.5 0 6.0 10 9.427 56,5642 B Final P 2.5 0 4.0 10 7.846 47,0743 C Final P 9.0 0.5 1.5 7.5 7.504 45,026

No Process

D1 Final PAA Final Bleaching

Cost Per tp (USD)

*6000 tp per day (USD)aCl (kg/tp) NaOH

(kg/tp)Peracetic

acid (kg/tp)

NaOH (kg/tp)

1 A Final PAA/P 1.5 0 1.5 10 5.677 34,0642 B Final PAA/P 2.5 0 1.0 10 5.346 32,0743 B Final PAA 2.5 0 2.0 1.5 4.466 26,7944 C Final PAA 9.0 0.5 0.4 1.0 4.784 28,706

D2

P

PAAD1

CONCLUSIONS

Conclusions

Some alternative method to produce 90% ISO brightness pulp had been investigated. Those are D0EOPD1D2, D0EOPD1P, D0EOPD1PAA, D0EOPD1PAA/P

Final Bleaching DPAA/P produce pulp which the best brightness stability, followed by DP, DPAA and DD respectively.

Extractive content of DPAA/P pulp is the lowest, followed by DP, DPAA, and DD respectively.

No major differences in morphology of fiber and strength properties of paper.

Final bleaching of DD sequences produce lowest COD but higher SS and chloride content. While, DP and DPAA produce lower SS but higher COD , but it can be treated easily in the waste water treatment plant.

DP and DPAA/P stages are significantly more expensive , while cost of DPAA maybe of interested when comparing with DD.

Thank you