Environmentally Benign Approaches for Pulp Bleaching, Volume 1 (Developments in Environmental Management)

Cover......Page 1
Environmentally Benign Approaches for Pulp Bleaching......Page 4
Contents......Page 6
Acknowledgements......Page 8
Preface......Page 10
Introduction......Page 12
References......Page 15
Pulping and bleaching......Page 18
Bleaching sequences......Page 23
Environmental issues in pulp bleaching......Page 28
References......Page 31
Introduction......Page 34
Overview of the process......Page 37
The basic chemistry of oxygen delignification......Page 38
Selectivity in oxygen delignification......Page 39
Oxygen delignification processes and equipment......Page 42
Process conditions......Page 51
Reinforcement of oxygen delignification stage with hydrogen peroxide and peracids......Page 53
Effects of oxygen delignification on pollution loads......Page 54
Effects of oxygen delignification on pulp quality......Page 55
Impact on recovery and energy consumption......Page 56
Washing......Page 57
Benefits and drawbacks of oxygen delignification......Page 58
References......Page 59
Introduction......Page 63
Chemical reactions of ozone with lignin and carbohydrates......Page 64
Process variables......Page 66
Bleaching of different types of pulp with ozone......Page 75
Ozone-bleaching processes and equipment......Page 80
Advantages......Page 85
Conclusions......Page 86
References......Page 87
Introduction......Page 90
Fundamental aspects of peroxide bleaching......Page 92
Factors affecting brightness development......Page 94
Peroxide bleaching processes......Page 104
Characteristics of peroxide-bleached pulps......Page 107
Process flowsheets......Page 108
Activation of hydrogen peroxide......Page 112
References......Page 117
Introduction......Page 121
Manufacture of Chlorine Dioxide......Page 122
Chemistry......Page 123
Generation of organochlorine compounds......Page 127
Formation of chlorate......Page 128
Process flowsheet and equipment......Page 129
Process conditions......Page 130
Bleaching sequences......Page 136
Effect of chlorine dioxide bleaching on pulp quality......Page 140
References......Page 141
Introduction......Page 143
Production of peroxyacids......Page 145
Application of peroxyacids in bleaching......Page 146
References......Page 154
Bleaching with hemicellulase enzymes......Page 156
Bleaching with ligninolytic enzymes......Page 166
References......Page 173
Performance of fungi in bleaching......Page 178
Effects on pulp properties......Page 183
Advantages......Page 184
References......Page 185
Introduction......Page 188
ECF bleaching......Page 190
Modified ECF sequences......Page 194
TCF bleaching......Page 195
References......Page 201
Introduction......Page 204
Bleaching with hydrogen peroxide......Page 205
Bleaching with dithionite......Page 216
Bleaching with formamidine sulphinic acid......Page 221
Bleaching with oxygen......Page 226
Bleaching with ozone......Page 231
Bleaching with peroxyacids......Page 235
References......Page 236
Introduction......Page 240
In-mill and ex-mill measures to achieve mill closure......Page 241
For kraft mills......Page 248
For sulphite......Page 265
Some practical considerations......Page 271
Economic considerations......Page 273
References......Page 276
Abbreviations......Page 280
Index......Page 284