选煤工程

1 INTRODUCTION 001
1.1　Coal Preparation is a Subsystem of Mining Operations 002
1.2　Objectives of Coal Cleaning 002
1.3　Coal Cleaning Processes 003
1.4　Coal Utilization 004
1.5　Environmental Considerations 005
1.5.1　Clean Air Act of 1990 005
1.5.2　Carbon Dioxide Emission 006
1.6　Transportation Modes of Coal 009
1.6.1　Coal Distribution Methods 009
1.6.2　River Barge Transportation Systems 011 2 COAL 013
2.1　Formation of Coal 014
2.2　Representative Structure of Chemical Groups in Bituminous Coal 015
2.3　Parr Formula and Classification of Coal by Rank 016
2.4　Coal Resources in the United States and West Virginia 020
2.4.1　Coal Resources Distribution in the United States 020
2.4.2　Coal Resources and Coal Seams in West Virginia 021 3 COAL CHARACTERIZATION 025
3.1　Coal Sample Preparation, Analyses, and Specifications 026
3.2　Qualities of Steam and Metallurgical Coals 028
3.3　Characterization of Coal for Combustion 031
3.3.1　Proximate and Ultimate Analyses 032
3.3.2　Sulfur Forms and Analyses (ASTM D3177—89, ASTM D2492—90) 033
3.3.3　Calorific Value of Coal - Adiabatic Bomb Calorimeter (ASTM D5865—99a) 035
3.4 Hardgrove Grindability Index (HGI) 035
3.5　Mineral Matter in Coal and Ash Analysis 037
3.5.1　Mineral Matter in Coal 037
3.5.2　Fusibility of Coal Ash 039
3.6　Coal Ash Characterization 040
3.6.1　Coal Ash Slagging Potential and Deposition Indicators 041
3.6.2　Slagging Potential and Fouling Tendency of a Coal 042
3.7　Characterization of Coal for Coke 045
3.7.1　Carbonization of Coal for Coke 045
3.7.2　Fluidity or Plastic Properties of Coal by Constant-Torque Gieseler Plastometer (Audibert-Arnu Dilatometer) 045
3.7.3　Expansion and Contraction of Coal by the Sole-Heated Oven 047
3.7.4　Swelling Properties of Coal Using a Dilatometer 048
3.7.5　Free-Swelling Index (FSI) 049
3.7.6　Stability Index for Coke Using the Tumbler Test 051
3.7.7　Metallurgical Coal 051
3.8　Coal Petrography 054
3.8.1　Coal Petrographic Components 054
3.8.2　Preparation of Coal Sample for Microscopical Analysis by Reflected Light- Stopes-Heerlen System 055
3.8.3　Coal Types and Corresponding Coking Properties 056 4 COMMINUTION AND SIZE REDUCTION 059
4.1　Objective of Size Reduction 060
4.2　Energy Requirements for Size Reduction 060
4.3　Principle of Size Reduction and Liberation 062
4.3.1　Reduction Ratio 062
4.3.2　Specific Energy 063
4.4　Unit Operations for Comminution 065
4.5　Size Distribution Analysis 071
4.5.1　Sieve Analysis 072
4.5.2　Rosin-Rammler Equation 073 5 SCREENING, CLASSIFICATION, AND DESLIMING 077
5.1 Screen Efficiency 078
5.1.1　Efficiency of Undersize Removal 078
5.1.2　Efficiency of Undersize Recovery 080
5.2 　Mass (Material) Balances 082
5.3 　Crushing and Grinding Circuits 086
5.3.1　Open Circuit 087
5.3.2　Closed Circuit 088
5.3.3　Relationship between Em and Er 091
5.4　Types of Crushers Used in Mineral Processing 092
5.5　Unit Operations for Screening, Classification, and Desliming 093
5.6 Classification by Hydrocyclone 095 6 WASHABILITY ANALYSIS 097
6.1　Float-and-Sink Test 098
6.1.1　Heavy Medium Suspensions for Float-and-Sink Tests 098
6.1.2　Float-and-Sink Test Procedures 098
6.2　Washability Data Analysis 099
6.3　Composite Washability Data for Coal 106 7 GRAVITY BASED SEPARATION PROCESSES 109
7.1　Fundamental of Momentum Transport and Settling Velocity of Particles in Fluid 110
7.1.1　Criteria for Viscous Flow (Stokes' Criterion for Small Particles) 110
7.1.2　Criteria for Turbulent Flow (Newton′s Criteria for Large Particles) 112
7.1.3　Allen Equation for Intermediate Flow Region 113
7.2 Equal Settling Terminal Velocity 113
7.2.1　Free Settling 113
7.2.2　Hindered-Settling 114
7.3　Concentration Criteria 115
7.4　Separation by Difference in Settling Rate 116
7.5　Sphericity of a Particle 117
7.6　Unit Operations for Coal Concentration 119
7.6.1　Jig 120
7.6.2　Dense Medium Vessel 125
7.6.3　Dense Medium Cyclone 125
7.6.4　Concentration Table 125
7.6.5　Water-Only Cyclone 131
7.6.6　Spiral Concentrators 133
7.6.7　Hindered-Settling Bed Separators 135
7.6.8　Pneumatic Coal Preparation Process 136 8 PROCESS EVALUATION AND PREDICTING COAL CLEANING RESULTS 141
8.1　Determination of Clean Coal Yield by Product Ash Analysis 142
8.2　Determination of Efficiency and Sharpness of Separation for a Coal Cleaning Unit 143
8.3 Prediction of Coal Cleaning Results 147 9 FROTH FLOTATION OF FINE COAL 149
9.1　Surface and Interfaces of Solid-Liquid-Gas 150
9.1.1　Young′s Equation 151
9.1.2　Dupree′s Equation 152
9.2　Effect of Coal Rank and Mineral Inclusion on Coal Floatability 152
9.3　Parameters Affecting the Rate of Flotation 153
9.3.1　Rate of Flotation in Stirred Tank Cell flotation 154
9.3.2　Pyrite Reverse Flotation Process for Desulfurization 155
9.4 　Weathered Coal (Oxidized Coal) 156
9.4.1　Sources of Weathered Coal 156
9.4.2　Characteristics of Oxidized Coal 156
9.4.3　Adverse Properties of Oxidized Coal on Coal Preparation 157
9.4.4　Coal Preparation Methods of Controlling the Effects of Oxidized Coal 157
9.5 Flotation Reagents 158
9.5.1　Effects of Non-Polar Hydrocarbon Oils 158
9.5.2　Common Flotation Reagents Used in Fine Coal Flotation 159
9.6　Flotation Conditioner for Weathered Coal 161
9.7　Calculation of Combustible Material Recovery 162
9.8　Unit Operations for Ultra-fine Coal 163
9.8.1　Stirred Tank Flotation Cell 163
9.8.2　Flotation Column 165 10 DEWATERING, THICKENING, AND DRYING 167
10.1　Introduction 168
10.2　Principle of Filtration (Cake formation in filtration) 169
10.2.1　Filter Cake Resistance, Rc 170
10.2.2　Filtration Equations 171
10.2.3　Methods of Filtration Operations 172
10.3　Filtration Experiment for Determination of Filtration Area 172
10.3.1　Constant Pressure Filtration Experiment 174
10.3.2　Estimation of Filtering Area Required for a Plate and Frame Filter Operation 175
10.4　Continuous Filtration Operations 179
10.5　Centrifugal Filtration 183
10.6　Vacuum Filters 184
10.7　Fluidized-Bed Coal Thermal Dryer 186
10.8　Flocculation and Coagulation 187
10.9　Sedimentation, Thickening, and Clarifying 190
10.9.1　Sedimentation Rate and Thickener Capacity 190
10.9.2　Kynch Method 193
10.9.3　Operating Line 195
10.9.4　High-capacity thickening 197 11 ON-LINE COAL QUALITY MONITORING AND MATERIAL HANDLINGS 199
11.1　X1-LiNX Coal Analyzer 200
11.2 　Combined Ash, Moisture and Elementary Belt Analyzer(AM-EBA) 201
11.3　Moisture Meter 202
11.4　Elemental Analyzer 203
11.5　Belt Scale 204
11.5.1　Singe-Station Conveyor Belt Scale 204
11.5.2　Dual-Station Conveyor Belt Scale 204
11.5.3　Multi-Station Conveyor Belt Scale 205
11.6　High Speed Sorting Gate 206 12 PLANT FLOWSHEET DESIGN 207
12.1　Coal Cleaning Circuits Configuration and Plant Flowsheet Design 208
12.2　Solids and Water Balances 215 13 COARSE REFUSE AND TAILINGS MANAGEMENT AND ENVIRONMENT 219
13.1 Tailing Dams 220
13.1.1　Methods of Tailings Dam Construction 220
13.1.2　Construction of Tailing Dam Wall Utilizing Cyclone Underflows 222
13.2　Contaminants from Reagents Used in Processed Plants 223
13.3　Water Balance in Tailings Impoundment 223
13.3.1　Water Gain and Loss in Impoundment 223
13.3.2　Water Reclamation System for Closed-Water Circuit 224
13.3.3　Design of a Settling Basin – An Example 225 14 HOMEWORK, PROJECTS, LABORATORY EXPERIMENTS, AND EXAMS 229
14.1 Homework 230
Homework #1 Coal Resources and Characterization 230
Homework #2 Environmental Impact of Coal Utilization, and Crushing and Comminution 231
Homework #3 Material Balances in Crushing Plant and Grinding Circuit 232
Homework #4 Washability Data and Prediction of Raw Coal Cleaning Results 232
Homework #5 Design Project 233
Homework #6 Flotation of Fine Coal and Oxidized Coal 234
Homework #7 Dewatering and Thickening and Online Quality Monitoring 235
14.2 Laboratory Experiments 236
Laboratory #1 - Preparation of ″representative″ Coal Sample and Chemical Analysis 236
Laboratory #2 - Size Distribution and Analysis 239
Laboratory #3 - Washability Analysis of Coal 241
Laboratory #4 - Froth Flotation 244
Laboratory #5 - Thickener Design 246
14.3 Exams 248
Exam 1 (Close books and notes) 248
Exam 2 (Close books and notes) 249
Exam 3 (Close books and notes) 251
Exam 4 (Open books) 255
Final Exam (Open book) 258 References 263 Subject Index 267