These Separation processes, are estimated to account for 40%-70% of capital and operating costs in process industry. Packed bed columns are widely employed in this area. Their usage also for direct heat transfer between gas and liquid, enlarge their importance. They are the best apparatuses, from thermodynamical point of view, for mass and heat transfer processes between gas and liquid phase.
Their wide spreading is due to low capital investments and operating costs. Since 1995 there has not been published a specialised book in this area, and this is a period of quick development of packed columns. Packed Bed Columns reflects the state of this field including the author's experience on creating and investigating of new packings, column internals and industrial columns.
* Considers the theories of mass transfer processes and shows how they help the construction of highly effective packings
* Complete information about the performance characteristics of different modern types of highly effective packings
* Considers the models for calculation and areas of their application
Packed bed columns are largely employed for absorption, desorption, rectification and direct heat transfer processes in chemical and food industry, environmental protection and also processes in thermal power stations like water purification, flue gas heat utilization and SO2 removal. These Separation processes, are estimated to account for 40%-70% of capital and operating costs in process industry. Packed bed columns are widely employed in this area. Their usage also for direct heat transfer between gas and liquid, enlarge their importance. They are the best apparatuses, from thermodynamical point of view, for mass and heat transfer processes between gas and liquid phase. Their wide spreading is due to low capital investments and operating costs. Since 1995 there has not been published a specialised book in this area, and this is a period of quick development of packed columns. Packed Bed Columns reflects the state of this field including the author's experience on creating and investigating of new packings, column internals and industrial columns. Considers the theories of mass transfer processes and shows how they help the construction of highly effective packings Complete information about the performance characteristics of different modern types of highly effective packings Considers the models for calculation and areas of their application
Front Cover 1
Title Page 4
Copyright Page 5
Preface 6
Acknowledgements 8
About the Author 10
Table of Contents 12
CHAPTER 1. BASIC INFORMATION 22
1.1. Basic information about packed bed columns 22
1.1.1. Short description of a packed bed column 22
1.1.2. Some terms largely used in the field of packed bed columns 23
1.1.3. Hydrodynamic regimes of packed bed columns 26
1.2. Basic differential equations in the theory of hydrodynamics and transfer processes 31
1.2.1. Differential equations of momentum, energy and mass transport 31
1.2.1.1. Hydrodynamic equations 31
1.2.1.1.1. Equation of continuity 31
1.2.1.1.2. Motion equations - equations of Navier-Stokes 32
1.2.1.2. Heat transport equations 33
1.2.1.2.1. Heat conduction 34
1.2.1.2.2. Differential equation of heat convection 38
1.2.2. Diffusion lows 41
1.2.2.1. Diffusion in immovable medium 41
1.2.2.2. Diffusion in movable medium 42
1.3. Similarity theory and dimensional analysis 46
1.3.1. Similarity theory 46
1.3.2. Dimensional analysis 53
1.3.3. Some additional remarks about the similarity theory and the dimensional analysis 56
1.4. Equilibrium in gas (vapour) - liquid systems 57
1.5. Basic models of mass transfer 60
1.5.1. Mass transfer coefficient 61
1.5.1.1. Partial mass transfer coefficients 61
1.5.1.2. Overall mass transfer coefficient 62
1.5.2. Physical models for calculation of the mass transfer coefficient 65
1.5.2.1. Molecular diffusion at interface 65
1.5.2.2. Models for determining the partial mass transfer coefficients 67
1.5.2.2.1. Model of immovable film 67
1.5.2.2.2. Penetration model 68
1.5.2.2.3. Model of Danckwerts 70
1.5.2.2.4. Model of Kishinevski 71
1.5.2.2.5. Model of diffusion boundary layer 71
1.5.3. Other dimensions of the partial and overall mass transfer coefficients and the driving force 72
1.5.4. Basic mathematical models of the mass transfer processes in industrial packed bed columns 73
1.5.4.1. Generally about the models 73
1.5.4.2. Piston flow model 74
1.5.4.2.1. Piston flow model with mass transfer coefficient 74
1.5.4.2.2. Piston flow model with height of a mass transfer unit 81
1.5.4.2.3. Piston flow model with number of theoretical stages and height of a theoretical stage 86
1.5.4.3. Diffusion model 91
1.6. Principle types of equations for calculation of the performance characteristics of the packing 93
1.6.1. Pressure drop 94
1.6.1.1. Pressure drop of dry packing 94
1.6.1.2. Pressure drop of irrigated packing 95
1.6.2. Liquid holdup 96
1.6.3. Effective surface area 96
1.6.3.1. Influence of the contact angle of wettability 97
1.6.3.2. Influence of the surface tension 99
1.6.3.3. Influence of the viscosity 99
1.6.4. Partial mass transfer coefficients 100
1.6.5. Peclet numbers 101
1.7. About the possibility of purely theoretical calculation of the performance characteristics of a packed column 102
Nomenclature 102
References 109
Appendix. Simple methods for determination of the diffusivity in gas and liquid phase 112
CHAPTER 2. INVESTIGATION OF THE MAIN PERFORMANCE CHARACTERISTICS OF PACKED BED COLUMNS 116
2.1. Investigations in cold stand 116
2.1.1. Experimental installations 116
2.1.1.1. Classical installation 117
2.1.1.2. Technological scheme of the experimental installation at the author's laboratory 118
2.1.1.3. Construction of the experimental column 122
2.1.1.3.1. Design of the liquid phase distributor 123
2.1.1.3.2. Supporting grid for the packing 126
2.1.1.3.3. Gas distributor 126
2.1.1.3.4. Gas/liquid phase separator at the points of measuring of the pressure drop 126
2.1.1.3.5. Sampling device for the liquid phase 128
2.1.2. Determination of the performance characteristics of the packings 129
2.1.2.1. Pressure drop, loading and flooding point 129
2.1.2.2. Liquid holdup 130
2.1.2.3. Determination of the axial mixing coefficients 135
2.1.2.3.1. Axial mixing in the liquid phase 136
2.1.2.3.2. Axial mixing in the gas phase 144
2.1.2.4. Determination of the mass transfer coefficients 144
2.1.2.4.1. Mass transfer coefficient for the piston flow model 145
2.1.2.4.1.1. Liquid-side controlled mass transfer coefficient 145
2.1.2.4.1.2. Gas-side controlled mass transfer coefficient 148
2.1.2.4.2. Determination of the mass transfer coefficients for the equations of the diffusion model 149
2.1.2.5. Wetted and effective surface area of the packing 150
2.1.2.5.1. Colour method 150
2.1.2.5.2. Methods based on determination of the holdup 151
2.1.2.5.3. Method using sublimation of naphthalene 151
2.1.2.5.4. Method of van Krevelen 152
2.1.2.5.5. Method using naphthalene sublimation and gas-side controlled absorption process 152
2.1.2.5.6. Method using data from evaporation of liquid from completely wetted packing and from absorption of very soluble gases 153
2.1.2.5.7. Method for determination of the effective surface area from data obtained in a packed bed column and a laboratory column with spheres 153
2.1.2.5.8. Method of Danckwerts 153
2.1.2.5.9. Method for investigation of the effective surface area at different properties of the liquid phase 157
2.1.2.5.10. End effect of effective surface area 158
2.1.2.5.11. Comparison of the methods for determination of the effective surface area 159
2.2. Investigations using hot stand 160
Nomenclature 164
References 166
CHAPTER 3. INDUSTRIAL PACKINGS 170
3.1. Requirements of the mass transfer theory to the packing form 170
3.2. Types of packings 174
3.2.1. Random packings 175
3.2.1.1. Description of the random packings 175
3.2.1.2. Performance characteristics of random packings 184
3.2.1.2.1. Performance characteristics of random packings obtained in cold experimental installations 184
3.2.1.2.1.1. Pressure drop 184
3.2.1.2.1.1.1. Experimental data 184
3.2.1.2.1.1.2. Equation for determination of the pressure drop 186
3.2.1.2.1.1.2.1. Pressure drop of dry packings 186
3.2.1.2.1.1.2.2. Pressure drop of irrigated packings 197
3.2.1.2.1.2. Loading, flooding and maximum efficient capacity 206
3.2.1.2.1.3. Liquid holdup 216
3.2.1.2.1.3.1. Liquid holdup under the loading point 216
3.2.1.2.1.3.2. Liquid holdup over the loading point 224
3.2.1.2.1.4. Wetted and effective surface area 228
3.2.1.2.1.4.1. Some experimental data 228
3.2.1.2.1.4.2. Equation for calculation of wetted and effective surface areas 238
3.2.1.2.1.5. Equation for calculation of the axial mixing coefficients 248
3.2.1.2.1.5.1. Axial mixing in the gas phase 248
3.2.1.2.1.5.2. Axial mixing in the liquid phase 253
3.2.1.2.1.5.3. Radial mixing in the liquid phase 257
3.2.1.2.1.6. Equation for calculation of the mass transfer coefficients 257
3.2.1.2.1.6.1. Gas-side controlled mass transfer coefficient 257
3.2.1.2.1.6.1.1. Coefficient for the piston flow model 257
3.2.1.2.1.6.1.2. Coefficient for the dispersion model 261
3.2.1.2.1.6.2. Liquid-side controlled mass transfer coefficient 263
3.2.1.2.1.6.2.1. Coefficient for the piston flow model 263
3.2.1.2.1.6.2.2. Coefficients for the diffusion model 272
3.2.1.2.2. Performance characteristics of random packings obtained in hot experimental installations 273
3.2.2. Structured packings 273
3.2.2.1. Structured packings with vertical smooth walls 274
3.2.2.1.1. Description of the structured packings with vertical smooth walls 274
3.2.2.1.2. Performance characteristics of structured packings with vertical smooth walls and their comparison with other types of packings 282
3.2.2.1.2.1. Pressure drop 282
3.2.2.1.2.1.1. Experimental data 282
3.2.2.1.2.1.2. Equation for determination of the pressure drop 284
3.2.2.1.2.1.2.1. Pressure drop of dry packings 284
3.2.2.1.2.1.2.2. Pressure drop and loading point of irrigated packings with vertical smooth walls 289
3.2.2.1.2.2. Dynamic holdup of packings with vertical smooth walls 294
3.2.2.1.2.3. Effective surface area of packings with vertical smooth walls 297
3.2.2.1.2.4. Gas-side controlled mass transfer coefficient of packings with vertical smooth walls 301
3.2.2.1.2.5. Liquid-side controlled mass transfer coefficient of packings with vertical smooth walls 308
3.2.2.1.3. Comparison of the structured packings with vertical smooth walls to other highly effective types of packings 312
3.2.2.2. Structured packing with boundary layer turbulizers (Turbo-pack) 315
3.2.2.2.1. Description of the structured packing with boundary layer turbulizers 315
3.2.2.2.2. Performance characteristics of the packings with boundary layer turbulizers 315
3.2.2.2.2.1. Pressure drop 315
3.2.2.2.2.1.1. Experimental data 315
3.2.2.2.2.1.2. Equation for determination of the pressure drop of packings with boundary layer turbulizers 317
3.2.2.2.2.1.2.1. Pressure drop of dry packings 317
3.2.2.2.2.1.3. Equation for determination of the pressure drop of packings with boundary layer turbulizers 318
3.2.2.2.2.1.3.1. Pressure drop of dry packings 318
3.2.2.2.2.1.3.2. Pressure drop and loading point of irrigated packings 319
3.2.2.2.2.2. Dynamic holdup of packings with boundary layer turbulizers 321
3.2.2.2.2.3. Mass transfer coefficient of packings with boundary layer turbulizers 322
3.2.2.2.2.3.1. Liquid-film controlled mass transfer of packings with boundary layer turbulizers 322
3.2.2.2.2.3.2. Gas-film controlled mass transfer of packings with boundary layer turbulizers 326
3.2.2.2.3. Comparison of the structured packings with boundary layer turbulizers with other highly effective types of packings 328
3.2.2.3. Structured packings of expanded metal 331
3.2.2.3.1. Description of the structured packings of expanded metal 331
3.2.2.3.2. Performance characteristics of the structured packings of expanded metal and their comparison with other types of packings 336
3.2.2.3.2.1. Pressure drop and loading point. Experimental data and equations 336
3.2.2.3.2.2. Dynamic holdup of Holpack packing 341
3.2.2.3.2.3. Effective surface area of Holpack packing 343
3.2.2.3.2.4. Mass transfer coefficients of Holpack packing 346
3.2.2.3.2.4.1. Liquid-film controlled mass transfer of Holpack packing 346
3.2.2.3.2.4.2. Gas-film controlled mass transfer of Holpack packing 348
3.2.2.3.3. Comparison of the packing Holpack with other highly effective types of packings 350
3.2.2.4. Structured packings of corrugated sheets 355
3.2.2.4.1. Description of the structured packings of corrugated sheets 355
3.2.2.4.2. Some experimental data for corrugated packings 358
3.2.2.4.3. Equations for calculation of structured packings of corrugated metal sheets 364
3.2.2.4.3.1. Pressure drop and liquid holdup 364
3.2.2.4.3.2. Loading and flooding point and maximum efficient capacity 377
3.2.2.4.3.3. Effective area of corrugated structured packings 377
3.2.2.4.3.4. Axial mixing 380
3.2.2.4.3.5. Calculation of the mass transfer coefficients 381
3.2.2.4.3.5.1. Liquid-side controlled mass transfer coefficient 381
3.2.2.4.3.5.2. Gas-side controlled mass transfer 382
3.2.2.4.3.6. Calculation of the height equivalent to a theoretical plate (HETP) 383
3.2.2.4.4. Modelling of some important industrial processes 393
3.2.2.4.5. Other investigations in the area of structured packings 394
3.2.2.5. Structured packings for extremely low liquid superficial velocity 394
3.2.3. Random or structured Packings? 407
3.3. Operation of the packed bed column in co-current flow 407
Nomenclature 408
References 416
Appendix. Geometrical data and performance characteristics of some highly effective packings 426
1. Random packings 426
2. Structured packings 443
2.1. Ralu-Pak 250 YC 443
2.2. Raschig Super-Pak 300 446
2.3. Mellapak 250.Y/X 448
2.4. Sulzer packing Mellapak Plus 451
2.5. Sulzer metal gauze packing, type CY 454
2.6. Sulzer plastic gauze packing, type BX 455
2.7. Mellacarbon 457
2.8. Mellagrid 458
2.9. Katapak-SP 461
CHAPTER 4. MARANGONI EFFECT AND ITS INFLUENCE ON THE MASS TRANSFER IN PACKINGS 463
Nomenclature 474
References 474
CHAPTER 5. MASS TRANSFER IN PACKED BED COLUMNS ACCOMPANIED BY CHEMICAL REACTION 476
5.1. Basic statement 476
5.2. Reaction-diffusion equations in case of reaction in the liquid phase 478
5.2.1. Slow chemical reaction 479
5.2.2. Fast chemical reaction 480
5.2.2.1. First order irreversible reaction 480
5.2.2.2. First order reversible reaction 482
5.3. Chemical reaction in the gas phase 482
5.4. A possibility to calculate a packed bed column in case of chemical reaction by means of experimental data 483
Nomenclature 490
Reference 492
CHAPTER 6. FOULING ON PACKINGS 493
6.1. Introduction 493
6.2. Experimental results 493
6.3. Comments about the fouling 502
6.4. Other possibility to eliminate the fouling or to reduce its effect 504
Nomenclature 508
References 508
CHAPTER 7. COLUMN INTERNALS 509
7.1. Support plates 509
7.2. Hold-down plates 517
7.3. Liquid distributors and redistributors 521
7.3.1. Liquid distributors 521
7.3.1.1. Single streams distributors 522
7.3.1.1.1. Constructions 522
7.3.1.1.2. Calculation 536
7.3.1.1.3. Some conditions for high quality liquid distribution using single streams distributors 540
7.3.1.2. Spray distributors 541
7.3.2. Liquid redistributors 543
7.4. Gas (vapour) distributors 549
7.5. Combined devices 553
Nomenclature 558
References 558
CHAPTER 8. DISTRIBUTION OF THE LIQUID AND GAS PHASE OVER THE CROSS-SECTION OF A PACKED BED COLUMN 560
8.1. Some measurements showing the great effect of maldistribution 560
8.2. Types of maldistribution 570
8.3. Maldistribution of the liquid phase 573
8.3.1. Basic equation for the distribution of the liquid in a packing 574
8.3.1.1. Determination of the coefficient of radial spreading of the liquid phase 575
8.3.2. Wall effect 582
8.3.2.1. Nature of the wall effect 582
8.3.2.2. Calculation of the liquid phase distribution in packed columns in the presence of wall effect 585
8.3.2.3. A possibility to eliminate the wall effect 591
8.3.2.3.1. Determination of the distance between the wall flow deflecting rings for elimination of the wall effect 594
8.3.2.3.2. Other devices for reduction of the wall effect 596
8.3.3. Liquid phase distribution under the distributor 598
8.3.4. Special packings for a redistribution layer 603
8.3.5. Other investigations about the distribution of the liquid phase 617
8.4. Gas maldistribution 619
8.4.1. Initial investigations on a maldistribution 619
8.4.2. Gas maldistribution investigation based on statistic methods 627
8.4.3. Gas maldistribution investigation based on a discrete cell model 629
8.4.3.1. Gas flow distribution model 631
8.4.3.1.1. Principle of the model 631
8.4.3.1.1.1. Structure of the packing bed 631
8.4.3.1.1.2. Bulk zone 631
8.4.3.1.1.3. Wall zone 634
8.4.3.1.1.4. Gas inlet zone 636
8.4.3.2. Calculation procedure 637
8.4.3.3. Experimental details 638
8.4.3.4. Results and discussion 641
8.4.3.4.1. Tracer distribution profiles 641
8.4.3.4.2. Velocity and pressure distribution profiles 643
8.4.3.4.2.1. Interface effect 645
8.4.3.4.2.2. Wall channel effects 646
8.4.3.4.2.3. Initial gas maldistribution effect 648
8.5. Ability of the dispersion model to account for the maldistribution 650
8.6. On the possibility to use the piston flow model for calculation of a packed column with maldistribution 652
8.7. Considerations and discussion about some old results for the effect of the liquid distribution quality 653
8.8. Presenting of the harmful effect of the liquid maldistribution on the mass transfer in the MacCabe-Thiele diagram in case of rectification, and reduction of this effect by means of redistributors 656
Nomenclature 662
References 665
Appendix. Determination of the distance between the wall flow deflecting rings (WFDR) for elimination of the wall effect 670
CHAPTER 9. EXAMPLES 683
9.1. Absorption of H2S from waste gases in staple cellulose fibre production 683
9.1.1. Calculation of a really built apparatus 683
9.1.2. Possibility for intensification of this apparatus based on more recent investigations 691
9.2. Desorption of O2 from feed water for boilers 693
9.3. Simultaneous absorption of H2S and CO2 in monoethanol amine (MEA) from technological gases in ammonia production 698
References 702
Index 703
| Erscheint lt. Verlag | 8.8.2006 |
|---|---|
| Sprache | englisch |
| Themenwelt | Naturwissenschaften ► Chemie ► Anorganische Chemie |
| Naturwissenschaften ► Chemie ► Technische Chemie | |
| Technik ► Umwelttechnik / Biotechnologie | |
| ISBN-10 | 0-08-046392-4 / 0080463924 |
| ISBN-13 | 978-0-08-046392-6 / 9780080463926 |
| Haben Sie eine Frage zum Produkt? |
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