ENVIRONMENTALLY FRIENDLY PULPING AND BLEACHING OF BAMBOOS AND BAGASSE FROM SUDAN By INSAF GALAL ELDIN KARAR (M.Sc. in Forestry U. of K) A Thesis Submitted in Partial Fulfilment of the Requirements of the Degree of DOCTOR OF PHILOSOPHY (Ph.D). Supervisor: Prof. Dr. Palmina Khristova Department of Forest Product and Industries Faculty of Forestry University of Khartoum 2004 DECLARATION I, hereby, declared that the work reported herein is a result of my own investigations, and has not been accepted in substance for any degree and is not concurrently being submitted for any degree. The work and conclusions of other persons have been acknowledged. Candidate Insaf Galaleldin Faculty of Forestry U. of K DEDICATION To the memory of my beloved sister Eman Galaleldien “may her soul rest in peace”. This thesis is also dedicated to my mother, brothers, sisters and friends. ACKNOWLEDGEMENTS I would like to express my sincere thanks and deepest appreciation to my supervisor Prof. Dr. Palmina Khristova, who suggested the research project, for her keen supervision, proper guidance, and continuous assistance throughout this study. Deepest gratitude and special thanks are extended to my external supervisors Prof. Dr Rudolf Patt and Dr. Othar Kordsachia for their thoughtful and constant academic assistance and support throughout my work, and for use of the facilities at the Institute for Wood Chemistry and Chemical Technology of Forestry-University of Hamburg,. My sincere thanks are due to DAAD for the financial support. Special thanks are due to Dr. Other Kordsachia for the work carried abroad. My gratitude is extended to the technical assistance provided by the staff and workers of the Institute for Wood Chemistry and Chemical Technology of Forestry-University of Hamburg especially Mrs. Ingi, Mr. Kristiana, Mss Kristina, Mrs Koni and Miss Iris. The help and support of the other members of the staff of the institute who helped me in one way or another is greatly appreciated. My acknowledgements are extended the to staff of German Embassy in Khartoum. I am also indebted to the CCTRU Ministry of Science and Technology, for use of some of their facilities. Sincere thanks are due to my family for their help and encouragement. I CONTENTS Page Acknowledgements i Contents ii List of Tables vi List of Figures viii English Abstract x Chapter 1 INTRODUCTION 1 INTRODUCTION 1 Objectives 6 Overall Objectives 6 Specific Objectives 6 Chapter 2 LITERATURE REVIEW 8 2 NON-WOOD PLANTS 8 2.1 NON-WOOD PLANTS STRUCTURE 9 2.1.1Non-Wood Plants Fibre 9 2.1.2 Gross Anatomical Features 12 2.1.3 Cell Wall Organization 15 2.2 FIBRE MORPHOLOGY 17 2.3 CHEMICAL COMPOSITION 19 2.3.1 Main Chemical Components 22 2.3.2 Extraneous Matter 25 2.4 PULPING 27 2.4.1 Pulping Processes Classification 28 2.4.2 Alkaline Pulping 32 2.4.2.1 Soda Pulping 33 2.4.2.2 Kraft pulping 34 2.4.2.3 Alkaline Sulphite Pulping 35 2.4.3 Alkaline Pulping with Additives 37 II 2.4.3.1 Anthraquinone Pulping 37 2.4.3.2 ASAM Pulping 39 2.5 PULP BLEACHING 41 2.5.1 Bleaching Processes Classification 42 2.5.2 Bleaching Control 43 2.5.3 Environmentally-friendly Bleaching Processes 46 2.5.3.1 Totally Chlorine-free Bleaching 47 2.6 GENERAL DESCRIPTION of SPECIES 50 2.6.1 Bagasse 50 2.6.2 Bamboos 54 2.6.2.1 Oxytenanthera abyssinica 55 2.6.2.2 Bambusa vulgaris 58 Chapter 3 EXPERIMENTAL PART 3.1 MATERIALS and METHODS 61 3.1.1 Materials Collection and Sampling 61 3.2 BASIC DENSITY 62 3.3 FIBRE CHARACTERIZATION 62 3.3.1 Fibre Measurements 62 3.3.2 Morphological Indices 62 3.4 RAW MATERIALS CHEMICAL COMPOSITION 63 3.4.1 Sampling 63 3.4.2 Methods of Analysis 63 3.5 PULPING 65 3.5.1 Raw Materials Preparation 65 3.5.2 Cooking Liquors Preparation 65 3.5.3 Pulping Equipment 65 3.5.4 Raw Materials Pre-treatment 65 3.5.5 Pulping Conditions 65 3.5.5.1 Soda and Kraft Pulping 66 3.5.5.2 Pulping with Additives 66 3.5.5.3 Alkaline Sulphite and ASAM Pulping 66 III 3.5.6 Characterization of Pulp Properties 67 3.6 PULP BLENDING 67 3.7 PULP BLEACHING 67 3.7.1 Bleaching Stages 67 3.7.2 Bleaching Equipment 68 3.7.3 Bleaching Pre-treatment 68 3.7.4 Bleaching Experiments 68 3.7.5 Bleaching Conditions 68 3.7.5.1 Bleaching Conditions of Bamboo 68 3.7.5.2 Bleaching Conditions of Bagasse 69 3.7.6 Bleaching Pre-trials 69 3.7.7 Bleached Pulp Evaluation 69 3.8 PULP TREATMENT 70 3.8.1 Pulp Beating 70 3.8.2 Handsheets Formation 70 3.9 PULP PROPERTIES EVALUATION 71 Chapter 4 RESULTS and DISCUSSION 4.1 BASIC DENSITY 73 4.2 FIBER MORPHOLOGY AND INDICES 75 4.3 RAW MATERIAL CHEMICAL COMPOSITION 77 4.3.1 Chemical Composition of Bagasse 77 4.3.2 Chemical Composition of Bamboos 78 4.4 PULPING WITH DIFFERENT PROCESSES AND PULP EVALUATION 81 4.4.1 Pulping of Bagasse 81 4.4.2 Pulping of Bamboos 88 4.3.2.1 Pulping of Oxytenanthera abyssinica 88 4.4.2.2 Pulping of Bambusa vulgaris 98 IV 4.5 PULP BLENDING 109 4.5.1 Pulp Blends of Bamboo with Bagasse 109 4.6 TCF BLEACHING 114 4.6.1 TCF Bleaching of Bagasse Pulps 114 4.6.1.1 Optimization of the TCF Bleaching of Bagasse Pulps 114 4.6.1.2 TCF Bleaching of Bagasse Pulps 118 4.6.1.3 Bleached Bagasse Pulps Evaluation 123 4.6.2 TCF Bleaching of Bamboo Pulps 123 4.6.2.1 Optimization of the TCF Bleaching of Oxytenanthera abyssinica Pulps 123 4.6.2.2 TCF Bleaching of Oxytenanthera abyssinica Pulps 130 4.6.2.3 Oxytenanthera abyssinica Bleached Pulps Evaluation 139 Chapter 5 CONCLUSIONS and RECOMMENDATIONS 140 REFERENCES 145 Arabic Abstract 165 V LIST of TABLES Page 1. Imports of paper and paper product--------------------------------------------------- 4 2. Approximate fibres dimensions of grasses ----------------------------------------- 12 3. Concentrations of important chemical constituents in various fibre sources----- 21 4. Pulping process-------------------------------------------------------------------------- 29 5. Typical pulp yields---------------------------------------------------------------------- 30 6. Standard Test Methods used in the chemical analysis of the raw materials ----- 64 7. Standards used in testing pulp handsheets ------------------------------------------ 71 8. Basic density and fibre characterization of Oxytenanthera abyssinica----------- 73 9. Basic density and fibre characterization of Bambusa vulgaris. ------------------- 74 10. Fibre characterization and morphological indices of bagasse-------------------- 75 11. Chemical composition of depithed bagasse from different locations. ----------- 78 12. Chemical composition of Oxytenanthera abyssinica from different locations. 79 13. Chemical composition of Bambusa vulgaris from different locations.---------- 80 14. Bagasse: soda and soda-AQ pulping conditions and pulp evaluation.----------- 82 15. Bagasse: AS-AQ pulping conditions and pulp evaluation.------------------------ 83 16. Oxytenanthera abyssinica: kraft and kraft-AQ pulping conditions and pulp evaluation. -------------------------------------------------------------------------------- 89 17. Oxytenanthera abyssinica: soda and soda-AQ pulping conditions and pulp evaluation. -------------------------------------------------------------------------------- 90 18. Oxytenanthera abyssinica: AS-AQ pulping conditions and pulp evaluation. ------------------------------------------------------------------------------ 91 19. Oxytenanthera abyssinica: ASAM pulping conditions and pulp evaluation.--- 92 20. Bambusa vulgaris: kraft and kraft-AQ pulping conditions and pulp evaluation.100 21. Bambusa vulgaris: soda and soda-AQ pulping conditions and pulp evaluation.101 22. Bambusa vulgaris AS-AQ pulping conditions and pulp evaluation ------------- 102 23. Bambusa vulgaris ASAM pulping conditions and pulp evaluation-------------- 103 VI 24. Blending of bagasse with Oxytenanthera abyssinica pulps. ---------------------- 110 25. TCF pre-bleaching trials of bagasse soda pulps ------------------------------------ 115 26. TCF pre-bleaching trials of bagasse soda-AQ pulps ------------------------------ 116 27. TCF pre-bleaching trials of bagasse AS-AQ pulps.-------------------------------- 117 28. TCF bleaching conditions of bagasse pulps.---------------------------------------- 119 29. TCF bleaching of bagasse soda pulps------------------------------------------------ 120 30. TCF bleaching of bagasse soda-AQ pulps.----------------------------------------- 121 31. TCF bleaching conditions of bagasse AS-AQ pulps. ------------------------------ 122 32. Bagasse: soda unbleached and bleached pulps evaluation ------------------------ 125 33. Bagasse: soda-AQ unbleached and bleached pulps evaluation ------------------ 126 34. Bagasse: AS-AQ unbleached and bleached pulps evaluation -------------------- 127 35. TCF pre-bleaching trials of Oxytenanthera abyssinica kraft pulps -------------- 131 36. TCF pre-bleaching trials of Oxytenanthera abyssinica ASAM pulps. ---------- 132 37. Oxytenanthera abyssinica: TCF bleaching conditions and bleached kraft pulp evaluation. ------------------------------------------------------------------- 133 38. Oxytenanthera abyssinica: TCF bleaching conditions and bleached ASAM pulp evaluation. ------------------------------------------------------------------ 134 39. Oxytenanthera abyssinica: kraft unbleached and bleached pulps evaluation.------------------------------------------------------------------------------- 135 40. Oxytenanthera abyssinica: ASAM unbleached and bleached pulps evaluation. ------------------------------------------------------------------------------ 136 VII LIST of FIGURES Page 1. Bamboo fibres-------------------------------------------------------------------------------