Description
Book SynopsisAmong those interested in drying are chemical engineers, energy specialists, and mechanical engineers. This book assists the process development engineer, the process engineer, and the plant engineer in selecting drying equipment.
Trade Review“The book is an excellent review of all drying operations employed in the process industries including the food industries.” (International Journal of Food Science & Technology, 1 May 2013)
“While intended for professionals in the field, the book is clearly written with abundant photographs and clear illustrations.” (Book News, 1 April 2012)
Table of ContentsPreface ix 1 Introduction 1
2 Drying as Part of the Overall Process 9
2.1 Residual Moisture / 9
2.2 Optimization of the Dewatering Step / 10
2.3 Process Changes to Simplify Drying / 10
2.4 Combination of Drying and Other Process Steps / 12
2.5 Nonthermal Drying / 15
2.6 Process Changes to Avoid Drying / 17
2.7 No Drying / 19
3 Procedures for Choosing a Dryer 21
3.1 Selection Schemes / 21
3.2 Processing Liquids, Slurries, and Pastes / 31
3.3 Special Drying Techniques / 33
3.4 Some Additional Comments / 34
3.5 Testing on Small-Scale Dryers / 37
3.6 Examples of Dryer Selection / 38
4 Convective Drying 41
4.1 Common Aspects of Continuous Convective Dryers / 42
4.2 Saturated Water Vapor Pressure / 43
4.3 Wet-Bulb Temperature / 44
4.4 Adiabatic Saturation Temperature / 46
4.5 Humidity Chart / 47
4.6 Water–Material Interactions / 49
4.7 Drying with an Auxiliary Material / 52
4.8 Gas Velocities / 54
4.9 Heat Losses / 55
4.10 Electrical Energy Consumption / 57
4.11 Miscellaneous Aspects / 59
4.12 Material Balance (kg·h−1) / 61
4.13 Heat Balance (kJ·h−1) / 61
4.14 Specific Heat of Solids / 63
4.15 Gas Flows and Fan Power / 64
4.16 Direct Heating of Drying Air / 65
5 Continuous Fluid-Bed Drying 67
5.1 General Description / 67
5.2 Fluidization Theory / 70
5.3 Drying Theory for Rectangular Dryers / 76
5.4 Removal of Bound Moisture from a Product in a Rectangular Dryer / 88
5.5 Circular Fluid-Bed Dryers / 90
6 Continuous Direct-Heat Rotary Drying 99
6.1 General Description / 99
6.2 Design Methods / 103
7 Flash Drying 117
7.1 General Description / 117
7.2 Design Methods / 120
7.3 Drying in Seconds / 122
7.4 Application of the Design Methods / 126
8 Spray Drying 133
8.1 General Description / 133
8.2 Single-Fluid Nozzle / 138
8.3 Rotary Atomizer / 143
8.4 Pneumatic Nozzle / 145
8.5 Product Quality / 149
8.6 Heat of Crystallization / 153
8.7 Product Recovery / 154
8.8 Product Transportation / 154
8.9 Design Methods / 155
9 Miscellaneous Continuous Convective Dryers and Convective Batch Dryers 163
9.1 Conveyor Dryers / 164
9.2 Wyssmont Turbo-Dryer / 169
9.3 Nara Media Slurry Dryer / 170
9.4 Anhydro Spin Flash Dryer / 172
9.5 Hazemag Rapid Dryer / 174
9.6 Combined Milling and Drying System / 176
9.7 Batch Fluid-Bed Dryer / 178
9.8 Atmospheric Tray Dryer / 182
9.9 Centrifuge–Dryer / 184
10 Atmospheric Contact Dryers 189
10.1 Plate Dryers / 189
10.2 Mildly Agitated Contact Dryers (Paddle Dryers) / 193
10.3 Vigorously Agitated Contact Dryers / 198
10.4 Vertical Thin-Film Dryers / 202
10.5 Drum Dryers / 204
10.6 Steam-Tube Dryers / 208
10.7 Spiral Conveyor Dryers / 212
10.8 Agitated Atmospheric Batch Dryers / 213
11 Vacuum Drying 217
11.1 Vacuum Drying / 219
11.2 Freeze-Drying / 232
11.3 Vacuum Pumps / 242
12 Steam Drying 251
12.1 Sugar Beet Pulp Dryer / 252
12.2 GEA Exergy Barr–Rosin Dryer / 255
12.3 Advantages of Continuous Steam Drying / 257
12.4 Disadvantages of Continuous Steam Drying / 257
12.5 Additional Remarks Concerning Continuous Steam Drying / 258
12.6 Eirich Evactherm Dryer / 258
13 Radiation Drying 263
13.1 Dielectric Drying / 264
13.2 Infrared Drying / 278
14 Product Quality and Safeguarding Drying 289
14.1 Product Quality / 289
14.2 Safeguarding Drying / 291
15 Continuous Moisture-Measurement Methods, Dryer Process Control, and Energy Recovery 313
15.1 Continuous Moisture-Measurement Methods for Solids / 313
15.2 Continuous Moisture-Measurement Methods for Gases / 321
15.3 Dryer Process Control / 327
15.4 Energy Recovery / 335
16 Gas–Solid Separation Methods 339
16.1 Cyclones / 340
16.2 Fabric Filters / 343
16.3 Scrubbers / 346
16.4 Electrostatic Precipitators / 349
17 Dryer Feeding Equipment 357
17.1 Fluid-Bed Dryers / 358
17.2 Direct-Heat Rotary Dryers / 360
17.3 Flash Dryers / 360
17.4 Spray Dryers / 361
17.5 Conveyor Dryers / 361
17.6 Hazemag Rapid Dryer / 363
17.7 Anhydro Spin Flash Dryer / 365
17.8 Plate Dryers / 365
17.9 Vigorously Agitated Contact Dryers / 365
17.10 Vertical Thin-Film and Drum Dryers / 365
Notation 369
Index 377
