Effects of Final Bleaching Stage Using Hydrogen Peroxide and Peracetic Acid (eq.) in the ECF Bleaching of Acacia D 0 E OP D 1 Kraft Pulps Presenter: Dede Ermawan (st110031) Adviser: Dr. Jiri Basta (Chairman) Dr. Mousa M. Nazhad Dr. Esa Lehtinen Presented on Master Theses Competetion, AIT, 16 th May 2011

INTRODUCTION

Background Problem Typically ECF Bleaching O-D0-EOP-D 1 -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 D 1 stage: T=70 °C, t=150 min, Consistency=10%, end pH= A Pulp B Pulp C Pulp

D 2 Stage Results D 2 stage: T=70 °C, t=180 min, Consistency=10%, end pH=

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

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

Evaluation Pulp QualityCostEnvironmental

Brightness Reversion

Extractive Content

Properties of pulps Kind of Pulps Fiber MorphologyOptical PropertiesStrength Properties No. of Fibers (Mill./g) Average Length (mm) Coarseness (mg/m) Fines Content (%weight) Fiber Width ( µ m) Opacity s coefficient (m ² /kg) k coefficient (m ² /kg) Tear Index (mN.m 2 /g) Tensile Index (Nm/g) z-span Nm/g D2 Mill A Final D B Final D C Final D A Final P B Final P C Final P A Final PAA/P ND B Final PAA/P ND B Final PAA ND Average S. deviation Max Min

Evaluation Pulp QualityCostEnvironmental

Evaluation of Environmental parameters BAT emission of Bleached kraft pulp:

Evaluation Pulp QualityCostEnvironmental

Cost Analysis NoProcess D1Final D Final Bleaching Cost Per tp (USD) *6000 tp per day (USD) aCl (kg/tp) NaOH (kg/tp) aCl (kg/tp) NaOH (kg/tp) 1A Final D ,699 2B Final D ,699 3C Final D ,190 NoProcess D1Final PFinal Bleaching Cost Per tp (USD) *6000 tp per day (USD) aCl (kg/tp) NaOH (kg/tp) Hydrogen peroxide (kg/tp) NaOH (kg/tp) 1A Final P ,564 2B Final P ,074 3C Final P ,026 NoProcess D1Final PAAFinal Bleaching Cost Per tp (USD) *6000 tp per day (USD) aCl (kg/tp) NaOH (kg/tp) Peracetic acid (kg/tp) NaOH (kg/tp) 1A Final PAA/P ,064 2B Final PAA/P ,074 3B Final PAA ,794 4C Final PAA ,706 D2P PAA

CONCLUSIONS

Conclusions Some alternative method to produce 90% ISO brightness pulp had been investigated. Those are D 0 E OP D 1 D 2, D 0 E OP D 1 P, D 0 E OP D 1 PAA, D 0 E OP D 1 PAA/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.