Bajpai Environmentally Benign Approaches for Pulp Bleaching

1. Auflage 2005
ISBN: 978-0-08-045794-9
Verlag: Elsevier Science & Techn.
Format: EPUB
Kopierschutz: 6 - ePub Watermark

E-Book, Englisch, 288 Seiten

Pulp and paper production has increased globally and will continue to increase in the near future. Approximately 155 millions tons of wood pulp is produced worldwide and about 260 millions is projected for 2010. To cope with the increasing demand, an increase in production and improved environmental performance is needed as the industry is under constant pressure to reduce environmental emissions to air and water. This book gives updated information on environmentally benign approaches for pulp bleaching, which can help solve the problems associated with conventional bleaching technologies.
* Main focus is on the environmentally friendly technologies that can help solve some of the problems associated with conventional bleaching technologies
* Information given is up-to-date, authoritative and cites the experiences of many mills and pertinent research, which is of interest to those working in the industry or intending to do so
* Covers in great depth all the aspects of various bleaching processes including environmental issues

Dr. Pratima Bajpai is currently working as a Consultant in the field of Paper and Pulp. She has a vast 36 years of experience in this field. She has worked at National Sugar Institute Kanpur (India), University of Saskatchewan (Canada), University of Western Ontario (Canada), and Thapar Center for Industrial Research and Development (India). Dr. Bajpai's main areas of expertise are industrial biotechnology, pulp and paper, and environmental biotechnology. She has contributed immensely to the field of industrial biotechnology and is a recognized expert in the field. Dr. Bajpai has written several advanced level technical books on environmental and biotechnological aspects of pulp and paper which have been published by leading publishers in the USA and Europe. She has also contributed chapters to a number of books and encyclopedia, obtained 11 patents, written several technical reports, and has implemented several processes in Indian Paper mills. Dr. Bajpai is an active member of the American Society of Microbiologists and is a reviewer of many international research journals. She has also handled several Sponsored Research Projects from industry and government agencies. She is an active member of the New York Academy of Science, American Society for Microbiology, and many more.

Autoren/Hrsg.

Bajpai, Pratima

Bajpai, P.

Inhaltsverzeichnis

1;Cover;1
2;Environmentally Benign Approaches for Pulp Bleaching;4
3;Contents;6
4;Acknowledgements;8
5;Preface;10
6;Introduction;12
6.1;References;15
7;General backgrounds;18
7.1;Pulping and bleaching;18
7.2;Bleaching sequences;23
7.3;Environmental issues in pulp bleaching;28
7.4;References;31
8;Options for environmentally benign bleaching;34
8.1;Oxygen delignification;34
8.1.1;Introduction;34
8.1.2;Overview of the process;37
8.1.3;The basic chemistry of oxygen delignification;38
8.1.4;Selectivity in oxygen delignification;39
8.1.5;Oxygen delignification processes and equipment;42
8.1.6;Process conditions;51
8.1.7;Reinforcement of oxygen delignification stage with hydrogen peroxide and peracids;53
8.1.8;Effects of oxygen delignification on pollution loads;54
8.1.9;Effects of oxygen delignification on pulp quality;55
8.1.10;Impact on recovery and energy consumption;56
8.1.11;Washing;57
8.1.12;Screening;58
8.1.13;Benefits and drawbacks of oxygen delignification;58
8.1.14;Conclusions;59
8.1.15;References;59
8.2;Ozone bleaching;63
8.2.1;Introduction;63
8.2.2;Chemical reactions of ozone with lignin and carbohydrates;64
8.2.3;Process variables;66
8.2.4;Bleaching of different types of pulp with ozone;75
8.2.5;Ozone-bleaching processes and equipment;80
8.2.6;Advantages;85
8.2.7;Environmental benefits;86
8.2.8;Conclusions;86
8.2.9;References;87
8.3;Hydrogen peroxide bleaching;90
8.3.1;Introduction;90
8.3.2;Fundamental aspects of peroxide bleaching;92
8.3.3;Factors affecting brightness development;94
8.3.4;Peroxide bleaching processes;104
8.3.5;Characteristics of peroxide-bleached pulps;107
8.3.6;Process flowsheets;108
8.3.7;Activation of hydrogen peroxide;112
8.3.8;Environmental aspects;117
8.3.9;References;117
8.4;Bleaching with chlorine dioxide;121
8.4.1;Introduction;121
8.4.2;Manufacture of Chlorine Dioxide;122
8.4.3;Chemistry;123
8.4.4;Generation of organochlorine compounds;127
8.4.5;Formation of chlorate;128
8.4.6;Process flowsheet and equipment;129
8.4.7;Process conditions;130
8.4.8;Bleaching sequences;136
8.4.9;Effect of chlorine dioxide bleaching on pulp quality;140
8.4.10;References;141
8.5;Bleaching with peroxyacids;143
8.5.1;Introduction;143
8.5.2;Production of peroxyacids;145
8.5.3;Application of peroxyacids in bleaching;146
8.5.4;Conclusions;154
8.5.5;References;154
8.6;Enzymatic prebleaching*;156
8.6.1;Bleaching with hemicellulase enzymes;156
8.6.2;Bleaching with ligninolytic enzymes;166
8.6.3;References;173
8.7;Fungal prebleaching*;178
8.7.1;Introduction;178
8.7.2;Performance of fungi in bleaching;178
8.7.3;Effects on pulp properties;183
8.7.4;Effects on effluent quality;184
8.7.5;Advantages;184
8.7.6;Limitations and future prospects;185
8.7.7;References;185
9;ECF and TCF bleaching;188
9.1;Introduction;188
9.2;ECF bleaching;190
9.2.1;Modified ECF sequences;194
9.3;TCF bleaching;195
9.4;Conclusions;201
9.5;References;201
10;Chlorine-free bleaching of secondary fibres;204
10.1;Introduction;204
10.2;Bleaching with hydrogen peroxide;205
10.3;Bleaching with dithionite;216
10.4;Bleaching with formamidine sulphinic acid;221
10.5;Bleaching with oxygen;226
10.6;Bleaching with ozone;231
10.7;Bleaching with peroxyacids;235
10.8;References;236
11;Closed-cycle bleach plant;240
11.1;Introduction;240
11.2;In-mill and ex-mill measures to achieve mill closure;241
11.3;Development of mill closure process;248
11.3.1;For kraft mills;248
11.3.2;For sulphite;265
11.4;Some practical considerations;271
11.5;Economic considerations;273
11.6;Conclusions;276
11.7;References;276
12;Abbreviations;280
13;Index;284