Handbook of Pulp

Handbook of Pulp. Edited by Herbert SixtaCopyright © 2006 WILEY-VCH Verlag GmbH & Co. KGaA, WeinheimISBN: 3-527-30999-3

Edited byHerbert Sixta

Further of Interest

H. Holik (Ed.)

Handbook of Paper and Board

2006, ISBN 3-527-30997-7

Handbook of Pulp

Edited byHerbert Sixta

Editor

Dr. Herbert SixtaLindenweg 74860 LenzingAustria

� All books published by Wiley-VCH arecarefully produced. Nevertheless, authors,editors, and publisher do not warrant theinformation contained in these books,including this book, to be free of errors.Readers are advised to keep in mind thatstatements, data, illustrations, proceduraldetails or other items may inadvertentlybe inaccurate.

Library of Congress Card No.: applied forBritish Library Cataloguing-in-Publication DataA catalogue record for this book is availablefrom the British Library.

Bibliographic information published byDie Deutsche BibliothekDie Deutsche Bibliothek lists this publicationin the Deutsche Nationalbibliografie; detailedbibliographic data is available in the Internet at<http://dnb.ddb.de>.

© 2006 WILEY-VCH Verlag GmbH & Co. KGaA,Weinheim

All rights reserved (including those oftranslation into other languages).No part of this book may be reproducedin any form – nor transmitted or translatedinto machine language without writtenpermission from the publishers. Registerednames, trademarks, etc. used in this book,even when not specifically marked as such,are not to be considered unprotected by law.

Printed in the Federal Republic of Germany.Printed on acid-free paper.

Cover Grafik-Design Schulz, FußgönheimTypesetting Kühn & Weyh, Satz und Medien,FreiburgPrinting Strauss GmbH, MörlenbachBinding Litges & Dopf Buchbinderei GmbH,Heppenheim

ISBN-13: 978-3-527-30999-3ISBN-10: 3-527-30999-3

This book is dedicated to my friend and teacher,Professor Dr. Dr. h.c. Josef (Joe) S. Gratzl.

VII

Preface XXIII

List of Contributors XXVII

List of Abbreviations XXIX

Volume 1

Part I Chemical Pulping 1

1 Introduction 3Herbert Sixta

1.1 Introduction 31.2 The History of Papermaking 41.3 Technology, End-uses, and the Market Situation 81.4 Recovered Paper and Recycled Fibers 141.5 Outlook 15

2 Raw Material for Pulp 21Gerald Koch

2.1 Wood 212.1.1 Chemical Composition of Wood 222.1.1.1 Cellulose 232.1.1.2 Hemicelluloses 282.1.1.3 Lignin 302.1.1.4 Extractives 332.1.1.5 Inorganic Components 392.1.2 Wood Structure and Morphology 412.1.2.1 Ultrastructure and Distribution of Cell Wall Components 412.1.2.2 Lignification of the Cell Walls 442.1.2.3 Functional Elements of the Conducting System 46

Contents

Handbook of Pulp. Edited by Herbert Sixta (Ed.)Copyright © 2006 WILEY-VCH Verlag GmbH & Co. KGaA, WeinheimISBN: 3-527-30999-3

VIII

2.1.3 The Microscopic Structure of Wood 482.1.3.1 Cell Types 482.1.3.2 Softwood and Hardwood Structure 502.1.3.3 Reaction Wood 542.1.3.4 Juvenile Wood 562.1.3.5 Secondary Changes 562.2 Outlook 592.2.1 Nano-structure of Fibers 592.2.2 Topochemical Distribution of Lignin and Phenolic Extractives 61

3 Wood Yard Operations 69Jörg B. Ressel

3.1 Raw Material Storage 693.2 Debarking 713.2.1 Debarking Methods 723.2.1.1 Drum Debarker 723.2.1.2 Rotary Debarker 763.2.1.3 Ring Debarkers 773.3 Chipping and Screening 793.3.1 Disc Chipper 803.3.2 Drum Chipper 843.3.3 The Andritz HQ™-Sizer and Rechipper 863.3.4 Chip Conditioner 873.3.5 Chipper Canter Line: Profiling Line in Softwood Sawmills 883.4 Chip screening 893.4.1 Mechanical Screening 893.4.2 Wind Screening 933.4.3 Air Density Separator (ADS) 943.5 Process Control and Automation 953.6 Transport and Handling Systems 953.6.1 Log Handling 973.6.2 Stationary Conveyor Systems 973.6.3 Chip Storage 983.6.3.1 Chip Storage Systems 1013.6.4 Wood Yard Losses and Waste Reduction 1043.6.4.1 Specific Causes of Waste Generation 1053.6.4.2 Pollution Prevention Options 105

4 Chemical Pulping Processes 109Herbert Sixta, Antje Potthast, Andreas W. Krotschek

4.1 Introduction 1094.2 Kraft Pulping Processes 1114.2.1 General Description 1114.2.2 Kraft Cooking Liquors 113

Contents

IX

4.2.3 Mass Transfer in Kraft Cooking 1224.2.3.1 Purpose of Impregnation 1224.2.3.2 Heterogeneity of Wood Structure 1234.2.3.3 Steaming 1304.2.3.4 Penetration 1334.2.3.5 Diffusion 1384.2.3.6 Diffusion Model 1514.2.3.7 Effect of Impregnation on the Uniformity of Delignification 1594.2.3.8 Numerical Solution of the Diffusion Model 1634.2.4 Chemistry of Kraft Cooking 164

Antje Potthast4.2.4.1 Lignin Reactions 1644.2.4.2 Reactions of Carbohydrates 1744.2.4.3 Reactions of Extractives 1814.2.4.4 An Overview of Reactions During Kraft Pulping 1834.2.4.5 Inorganic Reactions 1844.2.5 Kraft Pulping Kinetics 185

Herbert Sixta4.2.5.1 Introduction 1854.2.5.2 Review of Kraft Cooking Models 1884.2.5.3 Structure of a Selected Kinetic Model for Kraft Pulping 2114.2.6 Process Chemistry of Kraft Cooking 2294.2.6.1 Standard Batch Cooking Process 2294.2.6.2 Modified Kraft Cooking 2354.2.6.3 Polysulfide and Anthraquinone Pulping 3064.2.7 Multistage Kraft Pulping 3254.2.7.1 Prehydrolysis 3254.2.7.2 Prehydrolysis: Kraft Pulping 3454.2.8 Pulping Technology and Equipment 366

Andreas W. Krotschek4.2.8.1 Batch Cooking versus Continuous Cooking 3664.2.8.2 Batch Cooking Technology and Equipment 3674.2.8.3 Continuous Cooking Technology and Equipment 3774.3 Sulfite Chemical Pulping 392

Herbert Sixta4.3.1 Introduction 3924.3.2 Cooking Chemicals and Equilibria 3954.3.3 Impregnation 4034.3.4 Chemistry of (Acid) Sulfite Cooking 405

Antje Potthast4.3.4.1 Reactions of Lignin 4074.3.4.2 Reactions of Carbohydrates: Acid Hydrolysis 4164.3.4.3 Reactions of Extractives 4254.3.5 Process Chemistry of Acid Sulfite Pulping 427

Herbert Sixta

Contents

4.3.5.1 Basic Technology 4274.3.5.2 Influence of Reaction Conditions 4494.3.6 Alternative Sulfite Pulping Concepts 4654.3.6.1 Magnefite Process 4664.3.6.2 Two-Stage Neutral Magnefite (Bisulfite-MgO) 4674.3.6.3 Sivola Processes 4684.3.6.4 Stora Processes (Hydrogen Sulfite or Monosulfite-Acid Sulfite) 4724.3.6.5 Alkaline Sulfite Pulping 475

5 Pulp Washing 511Andreas W. Krotscheck

5.1 Introduction 5115.2 Pulp Washing Theory 5125.2.1 Overview 5125.2.2 Drainage 5135.2.3 Compressive Dewatering 5175.2.4 Diffusion 5175.2.5 Sorption 5195.3 Principles of Washing 5235.3.1 Dilution/Extraction Washing 5245.3.2 Displacement Washing 5245.3.3 Compressive Dewatering 5255.3.4 Multi-Stage Washing 5265.3.5 Fractional Washing 5285.4 Washing Parameters 5285.4.1 Overview 5285.4.2 Dilution Factor 5295.4.3 Feed and Discharge Consistencies 5325.4.4 pH 5335.4.5 Entrainment of Air 5345.4.6 Temperature 5355.4.7 Equipment-Specific Parameters 5355.5 Washing Efficiency 5375.5.1 Overview 5375.5.2 Wash Yield 5375.5.3 Displacement Ratio 5385.5.4 Norden Efficiency Factor 5395.5.5 Standardized Norden Efficiency Factor 5455.6 Washing Equipment 5475.6.1 General Remarks 5475.6.2 Rotary Drum Washers 5475.6.2.1 Conventional Drum Washers 5475.6.2.2 Drum Displacer 5495.6.3 Belt Washers 551

ContentsX

5.6.4 Diffusion Washers 5525.6.4.1 Atmospheric Diffuser 5525.6.4.2 Pressure Diffuser 5545.6.5 Roll Presses 5565.6.6 In-Digester Washing 557

6 Pulp Screening, Cleaning, and Fractionation 561Andreas W. Krotscheck

6.1 Introduction 5616.2 Screening Theory 5636.2.1 Introduction 5636.2.2 Flow Regime 5646.2.3 Fiber Passage and Reject Thickening 5666.2.4 Selective Fiber Passage 5706.3 Screening Parameters 5726.3.1 Equipment Parameters 5726.3.1.1 Screen Basket 5726.3.1.2 Rotor 5736.3.2 Operating Parameters 5756.3.2.1 Reject Rate 5756.3.2.2 Accept Flow Rate 5756.3.2.3 Feed Consistency 5776.3.2.4 Temperature 5776.3.2.5 Rotor Tip Velocity 5776.3.3 Furnish Parameters 5786.3.3.1 Pulp Fibers 5786.3.3.2 Contaminants 5796.3.3.3 Entrained Air 5796.4 Centrifugal Cleaning Theory 5796.4.1 Introduction 5796.4.2 Flow Regime 5806.4.3 Sedimentation 5816.4.4 Underflow Thickening 5846.4.5 Selective Separation 5856.5 Centrifugal Cleaning Parameters 5866.5.1 Cyclone Parameters 5866.5.2 Operating Parameters 5876.5.2.1 Flow Rate and Pressure Drop 5876.5.2.2 Feed Consistency 5876.5.2.3 Temperature 5876.5.3 Furnish Parameters 5876.5.3.1 Pulp Fibers 5876.5.3.2 Contaminants 5886.6 Separation Efficiency 588

Contents XI

6.6.1 Screening and Cleaning Efficiency 5886.6.2 Fractionation Efficiency 5906.6.2.1 Removal Efficiency 5906.6.2.2 Fractionation Index 5916.7 Screening and Cleaning Applications 5926.7.1 Selective Contaminant Removal 5926.7.1.1 Knots 5936.7.1.2 Shives 5936.7.1.3 Bark 5936.7.1.4 Sand and Stones 5936.7.1.5 Metals and Plastics 5946.7.2 Fractionation 5946.8 Systems for Contaminant Removal and Fractionation 5946.8.1 Basic System Design Principles 5946.8.2 Systems for Contaminant Removal 5966.8.2.1 Arrangement 5966.8.2.2 Fiber Loss versus Efficiency 5986.8.3 Systems for Fractionation 5996.9 Screening and Cleaning Equipment 6016.9.1 Pressure Screens 6016.9.2 Atmospheric Screens 6046.9.2.1 Secondary Knot Screens 6046.9.2.2 Vibratory Screens 6056.9.3 Hydrocyclones 605

Volume 2

7 Pulp Bleaching 609Herbert Sixta, Hans-Ullrich Süss, Antje Potthast, Manfred Schwanninger,and Andreas W. Krotscheck

7.1 General Principles 6097.2 Classification of Bleaching Chemicals 6107.2 Bleaching Operations and Equipment 613

Andreas W. Krotscheck7.2.1 Basic Rheology of Pulp-Liquor Systems 6147.2.2 Generic Bleaching Stage Set-Up 6167.2.3 Medium Consistency Pumps 6177.2.4 Medium Consistency Mixers 6197.2.4.1 High-Shear Mixers 6207.2.4.2 Static Mixers 6217.2.4.3 Atmospheric Steam Mixers 6227.2.5 Medium Consistency Reactors 6237.2.5.1 Atmospheric Upflow Reactors 623

ContentsXII

7.2.5.2 Atmospheric Downflow Reactors 6247.2.5.3 Pressurized Reactors 6257.2.6 Blowtank 6277.2.7 Agitators 6277.2.8 Washing 6287.3 Oxygen Delignification 6287.3.1 Introduction 6287.3.2 Chemistry of Oxygen Delignification 632

Manfred Schwanninger7.3.2.1 Bleachability 6347.3.2.2 Lignin Structures and their Reactivity 6347.3.2.3 Oxygen (Dioxygen) and its Derivatives 6417.3.2.4 A Principal Reaction Schema for Oxygen Delignification 6497.3.2.5 Carbohydrate Reactions in Dioxygen-Alkali Delignification

Processes 6577.3.2.6 Residual Lignin–Carbohydrate Complexes (RLCC) 6667.3.2.7 Inorganics (Metals) and their Role in the Protection/

Degradation of Cellulose 6687.3.3 Mass Transfer and Kinetics 671

Herbert Sixta7.3.3.1 Kinetics of Delignification 6727.3.3.2 Kinetics of Cellulose Chain Scissions 6857.3.3.3 Application of Surfactants 6877.3.4 A Model to Predict Industrial Oxygen Delignification 6887.3.4.1 Theoretical Base of the van Heiningen Model 6907.3.4.2 Case Study 6957.3.5 Process Variables 7017.3.5.1 Temperature 7017.3.5.2 Retention Time 7027.3.5.3 Alkali Charge 7037.3.5.4 pH Value 7047.3.5.5 Final pH 7057.3.5.6 Alkali Source 7067.3.5.7 Oxygen Charge, Oxygen Pressure 7077.3.5.8 Consistency 7087.3.6 Pulp Components and Impurities 7087.3.6.1 Effect of Metal Ion Concentration 7087.3.6.2 Residual Lignin Structures 7137.3.6.3 Carry-Over 7167.3.6.4 Xylan Content 7197.3.6.5 Selectivity of Oxygen Delignification 7207.3.7 Process and Equipment 7217.3.7.1 MC versus HC Technology 7217.3.7.2 Process Technology 7227.3.7.3 Process Equipment 731

Contents XIII

7.3.8 Pulp Quality 7337.4 Chlorine Dioxide Bleaching 7347.4.1 Introduction 7347.4.2 Physical and Chemical Properties and Definitions 7357.4.2.1 Behavior of Chlorine Dioxide in Aqueous Solution 7377.4.2.2 Inorganic Side Reactions during Chlorine Dioxide Bleaching of Wood

Pulps 7377.4.3 Generation of Chlorine Dioxide 7417.4.4 Chemistry of Chlorine Dioxide Treatment 745

Manfred Schwanninger7.4.4.1 Chlorination Products 7527.4.5 Performance of Chlorine Dioxide Bleaching 7547.4.5.1 Standard Chlorine Dioxide Bleaching 7547.4.5.2 Chlorine Dioxide Bleaching of Oxygen-Delignified Kraft Pulps 7597.4.5.3 Modified Chlorine Dioxide Bleaching 7617.4.6 Technology of Chlorine Dioxide Bleaching 770

Andreas W. Krotscheck7.4.7 Formation of Organochlorine Compounds 7717.5 Ozone Delignification 7777.5.1 Introduction 7777.5.2 Physical Properties of Ozone 7787.5.3 Ozone Generation 7827.5.4 Chemistry of Ozone Treatment 785

Manfred Schwanninger7.5.4.1 Ozone Decomposition 7867.5.4.2 Degradation of Lignin 7907.5.4.3 Degradation of Carbohydrates 7947.5.5 Process Conditions 7987.5.5.1 Mass Transfer 7987.5.5.2 Mixing and Mixing Time 8027.5.5.3 Effect of Pulp Consistency 8067.5.5.4 Effect of pH 8117.5.5.5 Effect of Temperature 8137.5.5.6 Effect of Transition Metal Ions 8147.5.5.7 Effect of Carry-Over 8167.5.5.8 Effect of Pretreatments and Additives 8187.5.5.9 Effect of Sodium Borohydride after Treatment 8227.5.5.10 Effect of Alkaline Extraction 8247.5.6 Technology of Ozone Treatment 826

Andreas W. Krotscheck7.5.6.1 Medium-Consistency Ozone Treatment 8267.5.6.2 High-Consistency Ozone Treatment 8277.5.6.3 Ozone/Oxygen Gas Management 8287.5.7 Application in Chemical Pulp Bleaching 8297.5.7.1 Selectivity, Efficiency of Ozone Treatment of Different Pulp Types 829

ContentsXIV

7.5.7.2 Effect of Ozonation on the Formation of Carbonyl and CarboxylGroups 840

7.5.7.3 Effect of Ozonation on Strength Properties 8417.5.7.4 Typical Conditions, Placement of Z in a Bleaching Stage 8437.6 Hydrogen Peroxide Bleaching 849

Hans-Ullrich Süss7.6.1 Introduction 8497.6.2 H2O2 Manufacture 8507.6.3 Physical Properties 8507.6.4 Chemistry of hydrogen peroxide bleaching 853

Manfred Schwanninger7.6.4.1 Decomposition of H2O2 8547.6.4.2 Residual Lignin 8567.6.4.3 Carbohydrates 8597.6.5 Process Parameters 860

Hans-Ullrich Süss7.6.5.1 Metals Management 8607.6.5.2 Alkaline Decomposition of H2O2 8627.6.5.3 Thermal Stability of H2O2 and Bleaching Yield 8637.6.5.4 Pressurized Peroxide Bleaching 8667.6.6 Technology of H2O2Bleaching 866

Andreas W. Krotscheck7.6.6.1 Atmospheric Peroxide Bleaching 8667.6.6.2 Pressurized Peroxide Bleaching 8677.6.7 Application in Chemical Pulp Bleaching 868

Hans-Ullrich Süss7.6.7.1 Stabilization of Brightness with H2O2 8737.6.7.2 Catalyzed Peroxide Bleaching 8777.6.7.3 Application in TCF Sulfite Pulp Bleaching 8777.6.7.4 Activators for H2O2 Bleaching 8807.7 Peracetic Acid in Pulp Bleaching 8807.8 Hot Acid Hydrolysis 8837.9 Alternative Bleaching Methods 8857.10 Bleach Plant Liquor Circulation 887

Andreas W. Krotscheck7.10.1 Introduction 8877.10.2 Intra-Stage Circulation and Circulation between Stages 8887.10.3 Open and Closed Operation of Bleaching Stages 8907.10.4 Construction Material Compatibility 8937.10.5 Implications of Liquor Circulation 893

Contents XV

8 Pulp Purification 933Herbert Sixta

8.1 Introduction 9338.2 Reactions between Pulp Constituents and Aqueous Sodium Hydroxide

Solution 9358.3 Cold Caustic Extraction 9428.3.1 NaOH Concentration 9428.3.2 Time and Temperature 9448.3.3 Presence of Hemicelluloses in the Lye 9458.3.4 Placement of CCE in the Bleaching Sequence 9488.3.5 Specific Yield Loss, Influence on Kappa Number 9498.3.6 Molecular Weight Distribution 9518.4 Hot Caustic Extraction 9528.4.1 Influence of Reaction Conditions on Pulp Quality and Pulp Yield 9538.4.1.1 NaOH Charge and Temperature in E, (EO), and (E/O) Treatments 9538.4.1.2 Xylan versus R18 Contents 9578.4.1.3 Purification versus Viscosity 9598.4.1.4 Purification versus Kappa Number and Extractives 9608.4.1.5 Composition of Hot Caustic Extract 9618.4.2 MgO as an Alternative Alkali Source 962

9 Recovery 967Andreas W. Krotscheck and Herbert Sixta

9.1 Characterization of Black Liquors 9679.1.1 Chemical Composition 9679.1.2 Physical Properties 9709.1.2.1 Viscosity 9709.1.2.2 Boiling Point Rise (BPR) 9709.1.2.3 Surface Tension 9719.1.2.4 Density 9719.1.2.5 Thermal Conductivity 9729.1.2.5 Heat Capacity [8,11] 9729.2 Chemical Recovery Processes 9739.2.1 Overview 9739.2.2 Black Liquor Evaporation 9749.2.2.1 Introduction 9749.2.2.2 Evaporators 9759.2.2.3 Multiple-Effect Evaporation 9779.2.2.4 Vapor Recompression 9799.2.3 Kraft Chemical Recovery 9809.2.3.1 Kraft Recovery Boiler 9809.2.3.2 Causticizing and Lime Reburning 9869.2.3.3 The Future of Kraft Chemical Recovery 9929.2.4 Sulfite Chemical Recovery 994

ContentsXVI

10 Environmental Aspects of Pulp Production 997Hans-Ulrich Süss

10.1 Introduction 99710.2 A Glimpse of the Historical Development 99810.3 Emissions to the Atmosphere 100210.4 Emissions to the Aquatic Environment 1004

10.5 Solid Waste 100610.6 Outlook 1007

11 Pulp Properties and Applications 1009Herbert Sixta

11.1 Introduction 100911.2 Paper-Grade Pulp 101011.3 Dissolving Grade Pulp 102211.3.1 Introduction 102211.3.2 Dissolving Pulp Characterization 102411.3.2.1 Pulp Origin, Pulp Consumers 102411.3.2.2 Chemical Properties 102611.3.2.3 Supramolecular Structure 104111.3.2.4 Cell Wall Structure 104711.3.2.5 Fiber Morphology 105111.3.2.6 Pore Structure, Accessibility 105211.3.2.7 Degradation of Dissolving Pulps 105611.3.2.8 Overview of Pulp Specification 1060

II Mechanical Pulping 1069Jürgen Blechschmidt, Sabine Heinemann, and Hans-Ulrich Süss

1 Introduction 1071Jürgen Blechschmidt and Sabine Heinemann

2 A Short History of Mechanical Pulping 1073Jürgen Blechschmidt and Sabine Heinemann

3 Raw Materials for Mechanical Pulp 1075Jürgen Blechschmidt and Sabine Heinemann

3.1 Wood Quality 10753.2 Processing of Wood 1076

Contents XVII

3.2.1 Wood Log Storage 10763.2.2 Wood Log Debarking 10763.2.3 Wood Log Chipping 1078

4 Mechanical Pulping Processes 1079Jürgen Blechschmidt and Sabine Heinemann

4.1 Grinding Processes 10794.1.1 Principle and Terminology 10794.1.2 Mechanical and Thermal Processes in Grinding 10804.1.2.1 Softening of the Fibers 10804.1.2.2 Defibration (Deliberation) of Single Fibers from the Fiber

Compound 10834.1.3 Influence of Parameters on the Properties of Groundwood 10844.1.4 Grinders and Auxiliary Equipment for Mechanical Pulping by

Grinding 10874.1.4.1 Pocket Grinders 10894.1.4.2 Chain Grinders 10904.1.4.3 Pulp Stones 10924.1.5 Pressure Grinding 10954.2 Refiner Processes 10984.2.1 Principle and Terminology 10984.2.2 Mechanical, Thermal, and Chemical Processes in the Refiner

Process 11004.2.3 Machines and Aggregates for Mechanical Pulping by Refining 1104

5 Processing of Mechanical Pulp and Reject Handling: Screening andCleaning 1113Jürgen Blechschmidt and Sabine Heinemann

5.1 Basic Principles and Parameters 11135.2 Machines and Aggregates for Screening and Cleaning 11145.3 Reject Treatment and Heat Recovery 1121

6 Bleaching of Mechanical Pulp 1123Hans-Ulrich Süss

6.1 Bleaching with Dithionite 11246.2 Bleaching with Hydrogen Peroxide 11266.3 Technology of Mechanical Pulp Bleaching 1134

7 Latency and Properties of Mechanical Pulp 1137Jürgen Blechschmidt and Sabine Heinemann

7.1 Latency of Mechanical Pulp 11377.2 Properties of Mechanical Pulp 1138

ContentsXVIII

III Recovered Paper and Recycled Fibers 1147Hans-Joachim Putz

1 Introduction 1149

2 Relevance of Recycled Fibers as Paper Raw Material 1153

3 Recovered Paper Grades 1157

3.1 Europe 11573.2 North America and Japan 11613.2.1 United States 11623.2.2 Japan 1163

4 Basic Statistics 11654.1 Utilization Rate 11674.2 Recovery Rate 11704.3 Recycling Rate 11734.4 Deinked Pulp Capacities 11744.5 Future Development of the Use of Recovered Paper 1175

5 Collection of Recovered Paper 11775.1 Pre-Consumer Recovered Paper 11785.2 Post-Consumer Recovered Paper 11785.2.1 Pick-Up Systems 11785.2.2 Drop-Off Systems 11795.3 Efficiency of Different Collection Systems 11805.4 Municipal Solid Waste 1181

6 Sources of Recovered Paper 1183

7 Sorting, Handling, and Storage of Recovered Paper 1187

7.1 Sorting 11877.2 Handling 11897.3 Storage 1190

8 Legislation for the Use of Recycled Fibers 11918.1 Europe 11928.2 United States of America 11958.3 Japan 1198

Appendix: European List of Standard Grades of Recovered Paper andBoard (February, 1999) 1203

Contents XIX

IV Analytical Characterization of Pulps 1211Erich Gruber

1 Fundamentals of Quality Control Procedures 12131.1 The Role of QC 12141.2 Basics of QC-statistics 12141.3 Sampling 12161.4 Conditions for Testing and/or Conditioning 12161.5 Disintegration 1217

2 Determination of Low Molecular-Weight Components 12192.1 Moisture 12192.2 Inorganic Components 12192.2.1 Ashes 12202.2.1.1 Total Ash 12202.2.1.2 Sulfated Ash 12202.2.1.3 Acid-Insoluble Ash 12202.2.2 Determination of Single Elements 12212.2.2.1 Survey of Chemical Procedures 12212.2.2.2 Atomic Absorption Spectroscopy (AAS) 12222.2.2.3 X-ray Fluorescence Spectroscopy (XFS) 12232.2.2.4 Electron Spectroscopy for Chemical Application (ESCA) 12232.3 Extractives 12242.3.1 Water Extractives 12242.3.1.1 Test Water 12242.3.1.2 Cold Water Extraction 12252.3.1.3 Hot Water Extraction 12252.3.1.4 Analysis of Water Extracts 12252.4 Chlorine Compounds 1225

3 Macromolecular Composition 12273.1 Lignin Content 12273.2 Extent of Delignification 12283.2.1 Roe Number 12283.2.2 Chlorine Number 12283.2.3 Kappa Number (Permanganate Number) 12283.3 Alkali Resistance and Solubility 12293.3.1 Alkali-Soluble Components 12293.3.2 a-, b-, and c-cellulose 12293.3.3 R18 and S18 values 12303.4 Composition of Polysaccharides 12313.4.1 Determination of Monosaccharides after Hydrolysis 12313.4.1.1 Gas Chromatography 12313.4.1.2 Thin-Layer Chromatography 1232

ContentsXX

3.4.1.3 Liquid Chromatography 12323.4.2 Determination of Pentosans after Hydrolysis 12333.4.3 Determination of Uronic Acids after Hydrolysis 12333.5 Functional Groups 12343.5.1 Carbonyl Functions 12343.5.1.1 Copper Number 12353.5.1.2 Sodium Borohydride Method 12363.5.1.3 Hydrazine Method 12363.5.1.4 Oxime Method 12363.5.1.5 Girard-P Method 12373.5.1.6 Cyanohydrin Method 12373.5.1.7 Fluorescent Dying 12373.5.2 Carboxyl Functions 12383.6 Degree of Polymerization (Molecular Mass) 12393.6.1 Solvents for Cellulose 12403.6.1.1 CUOXAM 12413.6.1.2 CUEN 12413.6.1.3 Iron Sodium Tartrate (EWNN) 12413.6.2 Diverse Average Values of Molecular Mass and Index of

Nonuniformity 12413.6.3 Methods to Determine Molar Mass (“Molecular Weight”) 12433.6.3.1 Osmosis 12433.6.3.2 Scattering Methods 12453.6.4 Viscosity Measurements 12483.6.4.1 Solution Viscosity as a Measure of Macromolecular Chain Length 12483.6.4.2 Viscosity Measurements on Cellulose Pulps 12513.6.5 Molecular Weight Distribution 12513.6.5.1 Fractional Precipitation or Solution 12513.6.5.2 Size-Exclusion (Gel-Permeation) Chromatography 1252

4 Characterization of Supermolecular Structures 1257

4.1 Crystallinity 12574.1.1 Degree of Crystallinity 12574.1.1.1 X-Ray Diffraction 12594.1.1.2 Solid-phase NMR-Spectroscopy 12614.1.1.3 Reaction Kinetics 12624.1.1.4 Density Measurements 12624.1.2 Dimension of Crystallites 12634.1.3 Orientation of Crystallites 12654.2 Accessibility, Voids, and Pores 12654.2.1 Porosity 12664.2.2 Accessible Surface 12674.3 Water and Solvent Retention 1268

Contents XXI

4.3.1 Total Water Uptake 12684.3.2 Free and Bound Water 1268

5 Fiber Properties 1269

5.1 Identification of Fibers 12695.1.1 Morphological Characterization 12695.1.2 Visible and UV Microscopy 12715.1.3 Electron Microscopy 12715.2 Fiber Dimensions 12725.2.1 Fiber Length and Width 12735.2.1.1 Microscopic Methods and Image Analysis 12735.2.1.2 Fiber Fractionation by Screening 12745.2.2 Coarseness 12755.3 Mechanical Properties 12755.3.1 Single Fiber Properties 12755.3.1.1 Wet Fiber Properties 12755.3.1.2 Mechanical Properties of Dry Fibers 12775.3.2 Sheet Properties 12785.3.2.1 Preparation of Laboratory Sheets for Physical Testing 12785.3.2.2 Determination of Mechanical Pulp Sheet Properties 12795.4 Optical Properties of Laboratory Sheets 1279

6 Papermaking Properties of Pulps 1281

6.1 Beating 12816.2 Drainage Resistance 12816.3 Drainage (Dewatering) Time 12836.4 Aging 12846.4.1 Accelerated Aging 1284

Index 1291

ContentsXXII

XXIII

Preface

Pulp is a fibrous material resulting from complex manufacturing processes thatinvolve the chemical and/or mechanical treatment of various types of plant mate-rial. Today, wood provides the basis for approximately 90% of global pulp produc-tion, while the remaining 10% originates from annual plants. Pulp is one of themost abundant raw materials worldwide which is used predominantly as a majorcomponent in the manufacture of paper and paperboard, and with increasingimportance also in the form of a wide variety of cellulose products in the textile,food, and pharmaceutical industries.

The pulp industry is globally competitive and attractive from the standpoint ofsustainability and environmental compatibility. In many ways, this industry is anideal example of a desirable, self-sustaining industry which contributes favorablyto many areas of our daily lives. Moreover, there is no doubt that it will continueto play an important role in the future.

Although the existing pulp technology has its origins in the 19th century, it hasstill a very high potential of further innovations covering many areas of science.Knowledge of the pulping processes has been greatly extended since Pulping Pro-cesses – the unsurpassed book of Sven A. Rydholm – was first published in 1965.Not only has the technology advanced and new technology emerged, but ourknowledge on structure–property relationships has also deepened considerably. Itis self-evident that the competitiveness of pulp and its products produced thereofcan only be maintained through continuous innovations at the highest possiblelevel.

A recent publication which comprised a series of 19 books on PapermakingScience and Technology, and was edited by Johan Gullichsen and Hannu Paulapuro,provided a comprehensive account of progress and current knowledge in pulpingand papermaking. The aim of the present book, however, is initially to provide ashort, general survey on pulping processes, followed by a comprehensive reviewin certain specialized areas of pulping chemistry and technology. Consequently,the book is divided into four part: Part I, Chemical Pulp; Part II, Mechanical Pulp;Part III, Recovered Paper and Recycled Fibers; and Part IV, the Analytical Charac-terization of Pulps.

In Part I, Chapter 2 and 3 describe the fundamentals of wood structure andwoodyard operations, whilst in Chapter 4 emphasis is placed on the chemistry

Handbook of Pulp. Edited by Herbert SixtaCopyright © 2006 WILEY-VCH Verlag GmbH & Co. KGaA, WeinheimISBN: 3-527-30999-3

XXIV Preface

and technology of both kraft and sulfite pulping, the mass transfer of cookingliquor into wood structure and chemical kinetics in alkaline pulping operations.The current technologies of dissolving pulp manufacture are also reviewed, cover-ing both multi-stage alkaline and acid sulfite pulping. Considerable effort wasdevoted in the subsequent chapters to present the fundamentals of pulp washing,screening, cleaning, and fractionation. These important mechanical pulpingoperations are followed by a comprehensive review of the state-of-the-art bleach-ing chemistry and technology. High-purity pulps are important raw materials forthe production of high added-value cellulose products, and the necessary purifica-tion processes are introduced in a separate chapter. A short overview on chemicalrecovery processes and pulp properties concludes Part I.

Parts II and III provide a survey of the latest technologies on mechanical pulpand recovered paper and recycled fibers.

Finally, Part IV deals with the analytical characterization of pulps. Since thewood and pulp components are closely associated within the cell wall, the analyti-cal characterization covers not only molecular but also supramolecular structures.

A project such as this could never have succeeded without input from contributorsof the very highest standard. I would like to express my sincere appreciation to thecontributors, for the high quality of their work and for their enthusiasm and com-mitment.

Individual sections of the manuscripts have been reviewed in detail by severalfriends and colleagues, and in this respect the suggestions and critical commentsof Josef Bauch of the University of Hamburg, Germany (Part I, Chapter 2), Hans-Georg Richter of the BFH, Germany (Part I, Chapter 2), Rudolf Patt of the Univer-sity of Hamburg, Germany (Part I, Chapters 3, 4 and 7), Othar Kordsachia of theBFH, Germany (Part I, Chapters 4, 7, 8 and 11), Richard Berry of Paprican, PointClaire, Canada (chlorine dioxide bleaching peracetic acid in pulp bleaching, hotacid hydrolysis and Chapter 10 in Part I, hydrogen peroxide bleaching in Part Iand II), Chen-Loung Chen and Michail Yu. Balakshin of NC State University,USA (chemistry of kraft and sulfite pulping), John F. Kadla of the University ofBritish Columbia, Vancouver, Canada (chemistry of oxygen-, ozone and hydrogenperoxide bleaching), Adriaan R.P. van Heiningen of the University of Maine, USA(oxygen delignification, ozone bleaching), James A. Olson of the University ofBritish Columbia, Vancouver, Canada (Part I, chapter 6), Andrea Borgards, R&DLenzing AG, Austria (Part I, Chapter 8), Hans Gr-stlinger of Lenzing Technik,Austria (bleaching technology), Wojciech Juljanski of Lenzing Technik, Austria(pulping technology) and Mikael Lucander, Ilkka Nurminen and Christoffer Wes-tin of the Oy Keskuslaboratorio, Espoo, Finland (Part II, Mechanical Pulping) aregratefully acknowledged. Moreover, I am very indebted to Alois Ecker of LenzingTechnik for his valuable support for the mathematical computations of kraft cook-ing and oxygen delignification kinetics. I also owe sincere thanks to the manage-ment of Lenzing AG for the assistance granted to me by their library services.

XXV

In addition to my gratitude to all of these people, I also thank my family fortheir great patience, understanding, and inspiring support.

Last, but not least, I would like to thank the publishers for the attractive presen-tation of this book, and the personnel at Wiley-VCH for their cooperation and skil-ful editorial work.

Lenzing, H. SixtaDecember 2005

Handbook of Pulp. Edited by Herbert SixtaCopyright © 2006 WILEY-VCH Verlag GmbH & Co. KGaA, WeinheimISBN: 3-527-30999-3

List of Contributors

Jürgen BlechschmidtWachbergstrasse 3101326 DresdenGermany

Erich GruberTU-DarmstadtMakromolekulare ChemieNachwachsender Rohstoffe64283 DarmstadtGermany

Sabine HeinemannKCL Science and ConsultingPulp and PaperP.O. Box 70EspooFinland

Gerald KochFederal Research Centre for Forestryand Forest ProductsInstitute for Wood Biology and WoodProtectionLeuschnerstrasse 9121031 HamburgGermany

Andreas W. KrotscheckLenzing Technik GmbHPulp Technology Division4680 LenzingAustria

Antje PotthastUniversity of Natural Resources andApplied Life Sciences ViennaDepartment of Chemistry andChristian-Doppler-LaboratoryMuthgasse 181190 ViennaAustria

Hans-Joachim PutzPaper Technology and MechanicalProcess EngineeringDarmstadt University of TechnologyAlexanderstrasse 864283 DarmstadtGermany

Jörg B. ResselDepartment of Wood ScienceUniversity of HamburgLeuschnerstrasse 9121031 HamburgGermany

Manfred SchwanningerBOKUUniversity of Natural Resources andApplied Life SciencesVienna Department of ChemistryDivision of BiochemistryMuthgasse 181190 ViennaAustria

XXVII

Handbook of Pulp. Edited by Herbert SixtaCopyright © 2006 WILEY-VCH Verlag GmbH & Co. KGaA, WeinheimISBN: 3-527-30999-3

Herbert SixtaLenzing AGBusiness Unit PulpWerkstraße 14860 LenzingAustria

Hans-Ulrich SüssDegussa AGGlobal Competence CenterActive Oxygen ProductsO2-AO-AT, 913-120Rodenbacher Chaussee 463594 HanauGermany

List of ContributorsXXVIII

List of Abbreviations

4OMeGlcA 4-O-methyl-bd-glucuronic acid-(1→2)-xylose)AAS atomic absorption spectroscopyAEC anion-exchange chromatographyAF&PA American Forest & Paper AssociationAFM atomic force microscopyAHG anhydroglucoseAMT accepted modern technologyAOX adsorbable organic halogenASAM alkaline sulfite with anthraquinone and methanolB.I.R. Bureau International de la RécupérationBAT best available technologyBLG black liquor gasificationBLGCC black liquor gasification with combined cycleBLPS black liquor dissolved polysaccharidesCCE cold caustic extractionCCOA carbazole-9-carboxylic acid [2-(2-aminooxy-ethoxy)-ethoxy]-amideCDE cupri-ethylene-diamine-solutionCE causticizing efficiencyCEPI Confederation of European Paper IndustriesCGW chemigroundwoodCI crystallinity indexCMP chemimechanical pulpCOD chemical oxygen demandCRMP chemi-refiner mechanical pulpCTC charge transfer complexCTMP chemi-thermomechanical pulp,CTO crude tall oilCZE capillary zone electrophoresisDAE differential algebraic equationDD drum displacerDDA dynamic drainage analyzerDDJ dynamic drainage jar

XXIXList of Abbreviations

DIP deinked pulpDP degree of polymerizationDSC differential scanning calorimetryDTPA diethylene triamino penta-acetateEAPC enhanced alkali profile cookingECCSA effective capillary cross-sectional areaECF elemental chlorine-freeEDR equivalent displacement ratioEDXA energy dispersive X-ray analysisEPA Environmental Protection AgencyERPA European Recovered Paper AssociationERPC European Recovered Paper CouncilESCA electron spectroscopy for chemical analysisESR electron spin resonanceEUGROPA European Paper Merchants AssociationFBSKP fully bleached softwood kraft pulpFEAD European Federation of Waste Management and Environmental

ServicesFEFCO European Federation of Corrugated Board ManufacturersFE-SEM field emission-SEMFSP fiber saturation pointFTIR Fourier transmission infra-redGPC gel-permeation chromatographyGSA General Services AdministrationHCE hot caustic extractionHEDP hydroxy ethylene 1,1-diphosphonic acidHHV higher heating valueHP-AEC high-performance anion-exchange chromatographyHVLC high-volume low-concentrationINTERGRAF International Confederation of Printing and Allied IndustriesIPPC Integrated Pollution and Prevention ControlISEC inverse size-exclusion chromatographyI-TEQ International Toxicity EquivalentLCC lignin–carbohydrate complexLMS laccase-mediator-systemLODP level-off DPLVHC low-volume high-concentrationLWC lightweight coatedMCC modified cooking circulationMFA microfibril angleMHW Ministry of Health and WelfareMITI Ministry of International Trade and IndustryMOW mixed office wasteMSW municipal solid waste

List of AbbreviationsXXX

MWD molecular weight distributionNCG noncondensable gasesNHV net heating valueNHWA National Household Recovery AnalysisNMR nuclear magnetic resonanceNPEs non-process elementsNSSC neutral sulfite semi-chemicalODE ordinary differential equationOXE oxidation equivalentPAD pulsed amperometric detectionPCDD polychlorinated dibenzo-p-dioxinsPCDF polychlorinated dibenzofuransPDI polydispersity indexPGW pressure groundwoodPHK prehydrolysis kraft pulpPRMP pressurized refiner mechanical pulpPSA pressure swing adsorptionRAC Recycling Advisory CouncilRDH rapid displacement heatingRLLC residual lignin–carbohydrate complexRMP refiner mechanical pulpRTS retention time, temperature, speedSAXS small-angle X-ray scatteringSC supercalenderedSEM scanning electron microscopySET single electron transferSGW stone groundwoodSRV solvent retention valueSSL spent sulfite liquorTCF totally chlorine freeTEM transmission electron microscopyTEQ toxic equivalency quantityTGW thermo groundwoodTMP thermomechanical pulpTOC total organic carbonToF-SIMS time-of-flight secondary ion mass spectroscopyTRS total reduced sulfurTSS total suspended solidsTTA total titrable alkaliUCC upper cooking circulationUMSP scanning UVmicrospectrophotometryVOC volatile organic compoundsVSA vacuum swing adsorption

WAXS wide-angle X-ray scattering

List of Abbreviations XXXI

WRV water retention valueXFS X-ray fluorescence spectroscopyXPS X-ray photoelectron spectroscopy

List of AbbreviationsXXXII