Reference Document on Best Available Techniques in the Pulp

6,48
MB and Paper Industry

509
stron

1107
ID JRC-IPTS Instituto de Prospectiva Tecnológica (IPTS)

2002
rok

EXECUTIVE SUMMARYi

PREFACE.xvi

SCOPE.xxxi

1 GENERAL INFORMATION.1

1.1 Paper consumption in Europe1

1.2 The European Pulp Industry 2

1.3 Geographical Distribution of the European Paper Industry.5

1.4 Economic situation 8

1.5 Environmental issues of the pulp and paper industry 9

1.6 Overview of pulp and paper manufacturing 10

1.7 Classification of pulp and paper mills .11

1.8 Presentation of BAT 15

2 THE KRAFT (SULPHATE) PULPING PROCESS 17

2.1 Applied Processes and Techniques18

2.1.1 Reception and storage of wood.18

2.1.2 Debarking .19

2.1.3 Wood Chipping and Screening.19

2.1.4 Cooking and delignification .19

2.1.5 Washing and screening.20

2.1.6 Oxygen delignification .21

2.1.7 Bleaching.22

2.1.8 Bleached Stock Screening 25

2.1.9 Drying25

2.1.10 Chemical and Energy Recovery System.25

2.1.11 Preparation of Bleaching Chemicals on site .27

2.1.11.1 Chlorine dioxide .27

2.1.11.2 Ozone28

2.1.11.3 Other bleaching chemicals29

2.2 Present Consumption/Emission Level for Integrated and Non-Integrated Mills .30

2.2.1 Overview of input/output30

2.2.2 Consumption and emission levels arising from process units 31

2.2.2.1 Wood consumption.31

2.2.2.2 Water consumption and waste from different proccess steps .32

2.2.2.3 Emissions to the atmosphere.39

2.2.2.4 Solid waste generation 48

2.2.2.5 Consumption of chemicals50

2.2.2.6 Use of Energy .52

2.2.2.7 Noise (local)57

2.2.2.8 Emission to soil and groundwater.57

2.3 Techniques to consider in the determination of BAT58

2.3.1 Dry debarking61

2.3.2 Extended modified cooking (batch or continuous) to a low kappa.62

2.3.3 Closed screening.65

2.3.4 Oxygen delignification .65

2.3.5 Ozone bleaching .68

2.3.6 ECF bleaching technique68

2.3.7 TCF bleaching technique71

2.3.8 Partial closure of the bleach plant.73

2.3.9 Collection of almost all spillages75

2.3.10 Efficient washing and process control 77

2.3.11 Stripping of the most concentrated contaminated condensates and re-use of most

condensates in the process 78

2.3.12 Use of sufficiently large buffer tanks for storage of concentrated or hot liquids from the

process. 80

2.3.13 Secondary or Biological Treatment - Aerobic Methods. 82

2.3.14 Tertiary treatment of wastewater with chemical precipitation . 85

2.3.15 Increase in the dry solids content of black liquor. 86

2.3.16 Installation of scrubbers on the recovery boiler . 87

2.3.17 Collection of weak gases for incineration in recovery boiler . 89

2.3.18 Collection and incineration of odorous gases (strong and weak gases) in the lime kiln 90

2.3.19 Collection and incineration of odorous gases (strong and weak gases) by use of a separate

furnace equipped with scrubbers for SO2 . 91

2.3.20 Installation of low NOx technology in auxiliary boilers (bark, oil, coal) and the lime kiln. 92

2.3.21 SNCR on bark boilers 93

2.3.22 Over Fire Air Technique (OFA) on recovery boilers. 94

2.3.23 Installation of improved washing of lime mud in recausticizing . 95

2.3.24 Electrostatic precipitator for dust reduction in bark boiler and lime kiln. 96

2.4 Best Available Techniques 98

2.4.1 Introduction. 98

2.4.2 BAT for kraft pulp and paper mills 99

2.5 Emerging Techniques 113

2.5.1 Gasification of Black Liquor 113

2.5.2 Use of SNCR on the recovery boiler 115

2.5.3 Removal of chelating agents by modest alkaline biological treatment or by use of kidneys .

117

2.5.4 Increased system closure combined with the use of kidneys . 119

2.5.5 Organosolv pulping 121

3 THE SULPHITE PULPING PROCESS. 123

3.1 Applied processes and techniques. 124

3.1.1 Woodhandling. 125

3.1.2 Cooking and delignification of unbleached pulp 125

3.1.3 Screening and washing of unbleached pulp . 125

3.1.4 Oxygen delignification/bleaching 125

3.1.5 Bleaching, screening and drying 126

3.1.6 Chemicals and Energy Recovery System. 127

3.1.7 Magnefite process 128

3.1.8 Neutral Sulphite Semi-Chemical Pulp . 129

3.1.9 Dissolving Sulphite Pulp 129

3.2 Present Consumption/Emission Level. 131

3.2.1 Overview of input/ouput 131

3.2.2 Consumption and emission levels arising from process units 132

3.2.2.1 Wood consumption. 133

3.2.2.2 Water consumption and emissions . 133

3.2.2.3 Consumption of chemicals . 136

3.2.2.4 Emissions to the atmosphere 137

3.2.2.5 Solid waste generation 138

3.3 Techniques to consider in the determination of BAT 140

3.3.1 Extended cooking to a low kappa 143

3.3.2 Oxygen delignification. 143

3.3.3 TCF bleaching 143

3.3.4 Partial closure of the bleach plant 144

3.3.5 Pre-treatment of wastewater from the oxygen stages in an ultrafiltration plant followed by

aerobic treatment of the total effluent . 144

3.3.6 Anaerobic pre-treatment of the condensate followed by aerobic treatment of the total effluent

. 144

3.3.7 Biological wastewater treatment 146

3.3.8 Installation of ESP and multi-stage scrubbers on the recovery boiler - chemical recovery and

abatement of air emissions 148

3.3.9 Reduction of odorous gases 151

3.3.10 Emission optimised recovery boiler by controlling the firing conditions 151

3.3.11 Measures to prevent uncontrolled development of normal operation and to reduce the

consequences of accidents 151

3.4 Best Available Techniques 153

3.4.1 Introduction 153

3.4.2 BAT for sulphite pulp and paper mills .154

3.5 Emerging Techniques 162

4 MECHANICAL PULPING AND CHEMI-MECHANICAL PULPING.163

4.1 Applied Processes and Techniques164

4.1.1 Groundwood Pulping164

4.1.1.1 Wood Handling.164

4.1.1.2 Grinding.165

4.1.1.3 Screening and Cleaning 165

4.1.2 Refiner Mechanical Pulps.166

4.1.2.1 Thermomechanical Pulping (TMP) 167

4.1.2.2 Chemi-mechanical Pulping.168

4.1.3 Bleaching of Mechanical Pulps 170

4.2 Present Consumption/Emission Levels172

4.2.1 Overview of input/output172

4.2.2 Consumption and emission levels arising from process units 175

4.2.2.1 Wood consumption.176

4.2.2.2 Water use 176

4.2.2.3 Wastewater emissions.177

4.2.2.4 Emissions to the atmosphere.179

4.2.2.5 Solid waste generation 181

4.2.2.6 Consumption of chemicals181

4.2.2.7 Energy use 182

4.2.2.8 Noise (local)185

4.3 Techniques to consider in the determination of BAT186

4.3.1 Emission control from the wood yard.187

4.3.2 Dry debarking.187

4.3.3 Minimisation of reject losses by using efficient reject handling stages188

4.3.4 Minimisation of disposal of rejects to landfill by incineration with energy recovery.189

4.3.5 Efficient washing and process control 191

4.3.6 Water recirculation in pulp and paper mill .191

4.3.7 CTMP mill effluent treatment. Closing up the water circuits by use of evaporation and burning

the concentrates .194