Title:
Gas cyclones and swirl tubes : principles, design, and operation
Personal Author:
Edition:
2nd ed.
Publication Information:
Berlin : Springer, 2008
Physical Description:
xxvi, 422 p. : ill. ; 24 cm.
ISBN:
9783540746942
9783642094163
General Note:
Also available online version
Added Author:
Electronic Access:
Full Text
DSP_RESTRICTION_NOTE:
Accessible within UTM campus
Available:*
Library | Item Barcode | Call Number | Material Type | Item Category 1 | Status |
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Searching... | 33000000017565 | TP159.S4 H63 2008 | Open Access Book | Book | Searching... |
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Summary
Summary
Believed to be a publishing first when originally brought out, this book covers all aspects of centrifugal gas cleaning devices. These are cyclones used as gas-solid separators for dedusting and as gas-liquid separators for demisting. The optimization of cyclone performance for any given task is a sought-after goal - but it is one that is seldom achieved in practice. This second edition will help mechanical and chemical engineers to achieve this optimization.
Table of Contents
1 Introduction | p. 1 |
1.1 Some Historical Background | p. 1 |
1.2 Removal of Particles from Gases | p. 6 |
1.2.1 Filtration | p. 8 |
1.2.2 Wet Scrubbers | p. 10 |
1.2.3 Centrifugal/Cyclonic Devices | p. 11 |
1.2.4 Knock-out Vessels and Settling Chambers | p. 12 |
1.3 A Closer Look at Centrifugal Gas Cleaning Devices | p. 12 |
1.3.1 Applications of Centrifugal Separators | p. 13 |
1.3.2 Classification of Centrifugal Separators | p. 17 |
1.3.3 Two Main Classes-Cyclones and Swirl Tubes | p. 20 |
2 Basic Ideas | p. 23 |
2.1 Gas Flow | p. 23 |
2.1.1 Swirling Flow | p. 23 |
2.1.2 Static and Dynamic Pressure | p. 26 |
2.2 Particle Motion | p. 27 |
2.3 Particle Size | p. 32 |
2.3.1 Definitions of Particle Size | p. 32 |
2.3.2 Particle Size Distribution | p. 33 |
2.4 Particle Density | p. 37 |
2.A Ideal Vortex Laws from N-S Eqs | p. 38 |
2.B Model Functions for Size Distributions | p. 41 |
2.B.1 The Normal Distribution | p. 42 |
2.B.2 The Log-Normal Distribution | p. 42 |
2.B.3 The Rosin-Rammler Distribution | p. 43 |
3 How Cyclones Work | p. 45 |
3.1 Flow in Cyclones | p. 45 |
3.1.1 Gas Flow Pattern | p. 45 |
3.1.2 Particle Flow | p. 49 |
3.2 Separation Efficiency | p. 51 |
3.2.1 Overall Separation Efficiency | p. 51 |
3.2.2 Grade-Efficiency | p. 51 |
3.2.3 Converting Between Overall Efficiency and Cut-size | p. 54 |
3.3 Pressure Drop | p. 54 |
3.A Worked Example: Calculating a Grade-Efficiency Curve | p. 56 |
4 Cyclone Flow Pattern and Pressure Drop | p. 59 |
4.1 Discussion | p. 59 |
4.1.1 Flow Pattern | p. 60 |
4.1.2 Pressure Drop | p. 61 |
4.2 Models for the Flow Pattern | p. 64 |
4.2.1 n-Type Model | p. 65 |
4.2.2 Barth | p. 66 |
4.3 Models for the Pressure Drop | p. 70 |
4.3.1 Models Based on Estimating the Dissipative Loss | p. 71 |
4.3.2 Core Model | p. 72 |
4.3.3 Purely Empirical Models | p. 77 |
4.4 Model Assumptions in Light of CFD and Experiment | p. 78 |
4.5 Overview | p. 82 |
4.A Worked Example for Calculating Cyclone Pressure Drop | p. 83 |
4.B The Meissner and Loffler Model | p. 85 |
5 Cyclone Separation Efficiency | p. 89 |
5.1 Discussion | p. 89 |
5.2 Models | p. 90 |
5.2.1 Equilibrium-orbit Models: the Model of Barth | p. 90 |
5.2.2 Time-of-Flight Models | p. 93 |
5.2.3 Hybrid Models | p. 96 |
5.2.4 Comparing the Models | p. 96 |
5.3 Comparison of Model Predictions with Experiment | p. 97 |
5.3.1 Agreement with Experiment in General | p. 97 |
5.3.2 A Case Study: the Effect of Cyclone Length | p. 98 |
5.4 Overview | p. 102 |
5.A Worked Example, Separation Performance | p. 103 |
5.B Models of Dietz and of Mothes and Loffler | p. 106 |
6 The Muschelknautz Method of Modeling | p. 111 |
6.1 Basis of the Model | p. 112 |
6.2 Computation of the Inner Vortex Cut-Point, x[subscript 50] | p. 118 |
6.3 Computation of Efficiency at Low Solids Loadings | p. 120 |
6.4 Determining if the Mass Loading Effect will Occur | p. 122 |
6.5 Overall Separation Efficiency when c[subscript o] > c[subscript oL] | p. 122 |
6.6 Computation of Pressure Drop | p. 124 |
6.A Example Problems | p. 125 |
6.A.1 Data from Hoffmann, Peng and Postma (2001) | p. 125 |
6.A.2 Data from Obermair and Staudinger (2001) | p. 128 |
6.A.3 Simulation of the Data from Greif (1997) | p. 129 |
6.B Incorporation of the 'Inner Feed' | p. 133 |
7 Computational Fluid Dynamics | p. 139 |
7.1 Simulating the Gas Flow Pattern | p. 140 |
7.1.1 Setting up the Finite Difference Equations | p. 140 |
7.1.2 Turbulence Models | p. 142 |
7.1.3 Simulations | p. 143 |
7.2 Simulating the Particle Flow | p. 147 |
7.2.1 Eulerian Modeling | p. 148 |
7.2.2 Lagrangian Particle Tracking | p. 148 |
7.2.3 3-D particle tracks | p. 148 |
7.3 Some Simulations of the Gas and Particle Flow in Cyclones | p. 149 |
7.3.1 LES Simulations of Derksen and van den Akker | p. 149 |
7.3.2 Some Remarks on CFD in Cyclones | p. 160 |
7.A Transport Equations | p. 161 |
8 Dimensional Analysis and Scaling Rules | p. 163 |
8.1 Classical Dimensional Analysis | p. 164 |
8.1.1 Separation Efficiency | p. 164 |
8.1.2 Pressure Drop | p. 167 |
8.2 Scaling Cyclones in Practice | p. 168 |
8.2.1 Approximately Constant Stk[subscript 50] over a Wide Range of Re | p. 168 |
8.2.2 Eu Only Weakly Dependent on Re | p. 171 |
8.2.3 Some other Considerations | p. 172 |
8.2.4 Stk-Eu Relationships | p. 173 |
8.A Inspecting the Equations of Motion | p. 176 |
8.A.1 Equation of Motion for the Gas | p. 176 |
8.A.2 Equation of Motion for a Particle | p. 176 |
8.B Sample Cyclone Scaling Calculations | p. 177 |
8.B.1 Inlet Velocity for Re Similarity | p. 177 |
8.B.2 Prediction from Scale Model | p. 178 |
9 Other Factors Influencing Performance | p. 183 |
9.1 The Effect of Solids Loading | p. 183 |
9.1.1 Effect on Separation Efficiency of Cyclones | p. 183 |
9.1.2 Models for Effect on Separation Efficiency | p. 185 |
9.1.3 Effect on the Separation Efficiency of Swirl Tubes | p. 191 |
9.1.4 Effect on the Pressure Drop of Cyclones | p. 192 |
9.1.5 Effect on the Pressure Drop Across Swirl Tubes | p. 194 |
9.1.6 Computing Performance with High Loading | p. 194 |
9.2 The Effect of the Natural Vortex Length | p. 195 |
9.2.1 The Nature of the Vortex End | p. 195 |
9.2.2 Wall Velocity Due to Core Precession | p. 197 |
9.2.3 The Significance of the Vortex End | p. 199 |
9.2.4 Models for the Natural Vortex Length | p. 203 |
9.A Predicting the Effect of Solids Loading on Cyclone Efficiency | p. 205 |
9.B Predicting the Effect of Loading on Cyclone Pressure Drop | p. 208 |
10 Measurement Techniques | p. 213 |
10.1 Gas Flow Pattern | p. 216 |
10.2 Pressure Drop | p. 218 |
10.3 Particle Flow | p. 219 |
10.4 Overall Separation Efficiency | p. 220 |
10.4.1 On-line Sampling of Solids | p. 221 |
10.5 Grade-Efficiency | p. 224 |
10.5.1 On-Line vs. Off-Line Size Analysis | p. 224 |
10.5.2 Sample Capture and Preparation | p. 225 |
10.5.3 Methods for Size Analysis | p. 226 |
10.A Estimate of Errors | p. 231 |
11 Underflow Configurations and Considerations | p. 235 |
11.1 Underflow Configurations | p. 235 |
11.2 Importance of a Good Underflow Seal | p. 239 |
11.2.1 Inleakage Example | p. 242 |
11.3 Upsets Caused by 'Too Good' an Underflow Seal | p. 243 |
11.4 Second-Stage Dipleg Solids 'Backup' | p. 246 |
11.5 Hopper 'Crossflow' | p. 248 |
11.6 Hopper Venting Options | p. 250 |
11.A Dipleg Calculation | p. 253 |
11.B Moment Balance on Flapper Valve Plate | p. 253 |
11.B.1 Example | p. 256 |
12 Some Special Topics | p. 257 |
12.1 Cyclone Erosion | p. 257 |
12.1.1 Inlet 'Target Zone' | p. 257 |
12.1.2 Lower Cone Section | p. 260 |
12.1.3 Vortex Tube Outer Surface | p. 263 |
12.1.4 Erosion Protection | p. 268 |
12.2 Critical Deposition Velocity | p. 279 |
12.3 High Vacuum Case | p. 281 |
12.3.1 Application to Cyclone or Swirl Tube Simulation | p. 282 |
12.A Worked Example for Critical Deposition Velocity | p. 283 |
12.B Worked Example with Slip | p. 283 |
13 Demisting Cyclones | p. 287 |
13.1 Liquid Creep and 'Layer Loss' | p. 288 |
13.2 Demisting Cyclone Design Considerations | p. 290 |
13.3 Some Vapor-Liquid Cyclone Design Geometries and Features | p. 292 |
13.4 Estimating Inlet Drop Size for Two-Phase Mist-Annular Flow | p. 299 |
13.4.1 Estimating Drop Size Distribution | p. 301 |
13.5 Modeling the Performance of Vapor-Liquid Cyclones | p. 302 |
13.5.1 Computation of Cut Size | p. 302 |
13.5.2 Computation of Efficiency at Low Inlet Loadings | p. 303 |
13.6 Criteria for Determining if 'Mass loading' ('Saltation') Occurs | p. 303 |
13.6.1 Overall Separation Efficiency when c[subscript o] > c[subscript oL] | p. 304 |
13.7 Re-entrainment From Demisting Cyclones | p. 305 |
13.7.1 Re-entrainment Mechanisms and Governing Parameters | p. 305 |
13.7.2 Data for Re-entrainment | p. 308 |
13.A Example Calculations of Droplet Sizes in Pipe Flow | p. 311 |
13.A.1 Finding the Mean Droplet Size | p. 311 |
13.A.2 Finding the Droplet Size Distribution | p. 312 |
13.B Flow Distribution in Parallel Demisting Cyclones | p. 312 |
13.B.1 Calculation of Flow Distribution | p. 317 |
13.B.2 Calculation of Liquid Level Difference | p. 317 |
13.C Method for Estimating Wall Film Thickness and Velocity | p. 318 |
13.C.1 Two-Phase, Co-current, Annular Force Balance, Resolved in the Axial Direction | p. 320 |
13.C.2 Friction Factors and Shear Stresses | p. 321 |
13.C.3 Final Form of Void Fraction Equation | p. 323 |
13.D Example calculation | p. 324 |
14 Foam-Breaking Cyclones | p. 327 |
14.1 Introduction | p. 327 |
14.2 Some Design Considerations and Factors Influencing Behavior | p. 330 |
14.3 Applications | p. 334 |
14.4 Estimating Submergence Required to Prevent Gas 'Blow Out' | p. 334 |
14.A Example Calculation of Submergence Required | p. 340 |
15 Design Aspects | p. 341 |
15.1 Cylinder-on-Cone Cyclones with Tangential Inlet | p. 341 |
15.1.1 Some Standard Cyclone Designs | p. 341 |
15.1.2 Design of the Inlet | p. 342 |
15.1.3 Design of the Cone Section | p. 349 |
15.1.4 Solids Outlet Configurations | p. 350 |
15.1.5 Vortex Finder Geometries | p. 353 |
15.1.6 Cyclone Length | p. 363 |
15.1.7 Cyclone Roof | p. 364 |
15.1.8 Cyclone Operating Conditions | p. 367 |
15.2 Design of Swirl Tubes with Swirl Vanes | p. 368 |
15.2.1 Design of the Inlet Vanes | p. 368 |
15.2.2 Calculation of Inlet 'Throat' Area | p. 370 |
15.2.3 Length of the Swirl Tube Body and the Solids Exit | p. 372 |
15.A Example Calculation of the Throat Area | p. 373 |
15.B Construction of Vane "Cut-out" pattern | p. 374 |
16 Multicyclone Arrangements | p. 381 |
16.1 Cyclones in Series | p. 381 |
16.2 Cyclones in Parallel | p. 382 |
16.A Example Calculation for Multicyclone Arrangements | p. 391 |
List of Symbols | p. 397 |
List of Tradenames | p. 403 |
References | p. 405 |
Index | p. 411 |