DR - EXHIBIT 1016
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`DRL001
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`DRL - EXHIBIT 1016
`DRL001
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`

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`Mixing in the Process Industries
`
`Second edition
`
`Editors: N Hamby, M F Edwards, A W Nienow
`
`: UTTERWORTH
`E INEMANN
`
`DRL - EXHIBIT 1016
`DRL002
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`

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`Butterworth-Heinemann
`Linacre House, Jordan Hill, Oxford OX2 8DP
`225 Wildwood Avenue, Woburn, MA 0 1801-2041
`A division of Reed Educational and Professional Publishing Ltd
`& A member of the Reed ,Elsevier pie group
`
`ioPM
`-rP
`f ~6
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`I qo,r:
`
`OXFORD AUCKLAND BOSTON
`JOllANNESBURG MELBOURNE NEW DELHI
`
`First published 1985
`Reprinted 1987, 1989, 1990
`Second edition 1992
`Paperback edition 1997
`Reprinted 2000
`
`©Reed Educational and Professional Publishing Ltd 1985, 1992
`
`All rights reserved. No part of this publication
`may be reproduced in any material form (including
`photocopying or storing in any medium by electronic
`means and whether or not transiently or incidentally
`co some other use of this publication) without the
`written permission of the copyright holder except in
`accordance with the provisions of the Copyright,
`Designs and Patents Act 1988 or under the te1ms of a
`licence issued by the Copyright Licensing Agency Ltd,
`90 Tottenham Court Road, London, England W IP OLP.
`Applications for the copyright holder's written permission
`to reproduce any part of this publication should be addressed
`to the publishers
`
`British Library Cataloguing in Publication Data
`A catalogue record for this book is available from the British Library
`
`Libnry of Cong1•css Cataloguing in Publication Data
`A catalogue record for this book is available from the Library of Congress
`
`ISBN 0 7506 3760 9
`
`Printed and bound in Great Britain by
`Antony Rowe Ltd, Chippenham, Wiltshire
`
`Cooper Union Library
`JUN 2 8 2000
`
`DRL - EXHIBIT 1016
`DRL003
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`

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`Contents
`
`Preface xi
`List of contributors xii
`
`1.
`
`Introduction to mixing problems 1
`A. W. Nienow, N. Hamby and M. F. Edwards
`Range of problems 2
`1.1
`Problem identification and philosophy 2
`1.1.1
`Single phase liquid mixing 2
`1.1.2
`1.1.3
`Solid- liquid mixing 3
`Gas- liquid mixing 3
`1.1.4
`1.1.5
`Liquid-liquid (immiscible) mixing 4
`1.1.6
`Three-phase contacting 4
`Solids mixing 4
`1.1. 7
`1.1.8
`Heat transfer 5
`Overmixing 5
`1.1.9
`1.2 Mixing mechanisms 5
`Liquid mixing 5
`1.2.1
`Solids mixing 10
`1.2.2
`Assessment of mixture quality 16
`1.3
`Rheology 18
`1.4
`Notation 22
`References 23
`
`2. C'1aracterization of powder mixtures 25
`N. Hamby
`2.1
`A qualitative approach 25
`A quantitative approach 26
`2.2
`2.2.1
`Powder sampling 27
`2.2.2
`Limiting variance values 28
`2.2.3
`Statistical inference 30
`A typical mixture analysis 33
`2.3
`Non-ideal mixtures 40
`2.4
`References 41
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`3. The selection of powder mixers 42
`N. Hamby
`The range of mixers available 42
`3.1
`Tumbler mixers 42
`3.1.l
`Convective mixers 42
`3.1.2
`High shear mixers 47
`3.1.3
`Fluidized mixers 48
`3.1.4
`Hopper mixers 51
`3.1.5
`3.1.6 Multi-purpose mixers 52
`Selection based on process requirements 52
`3.2
`Selection based on mixture quality 54
`3.3
`Selection based on mixing costs 59
`3.4
`Selection decision chart 61
`3.5
`References 61
`·
`
`4. Mixing in fluidized beds 62
`D. Ge/dart
`4.1
`Introduction 62
`Fundamentals of fluidization 63
`4.2
`4.2.1 Minimum fluidization 63
`4.2.2
`Types of fluidization 64
`The role of bubbles 67
`4.2.3
`Types of mixing problems 68
`4.3
`4.4 Mixing in non-segregating systems 69
`4.4.1
`Background theory 69
`Turnover times 71
`4.4.2
`4.4.3
`Residence time distributions 71
`4.5 Mixing in segregating systems 73
`4.5.1 Mixing criteria 73
`4.5.2
`Powders containing particles of equal density but
`variable size 74
`4.5.3 Powders containing species of differing densities and
`sizes 75
`Concluding remarks 76
`4.6
`Notation 77
`References 78
`
`5. The mixing of cohesive powders 79
`N. Hamby
`5.1
`Introduction 79
`Interparticulate forces 82
`5.2
`5.2.1
`Bonding due to moisture 82
`Electrostatic bonding 88
`5.2.2
`Van der Waals' force bonding 89
`5.2.3
`5.2.4
`Interaction of the bonding forces 91
`Selection of mixer 94
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`5.3
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`5.4 Mixture quality for cohesive systems 95
`References 96
`
`6. The dispersion of fine particles in liquid media 99
`G. D. Parfitt and fl. A. Barnes
`6.1
`Introduction 99
`6.2
`Stages in the dispersion process 100
`6.2.1
`Incorporation 100
`6.2.2 Wetting 102
`6.2.3
`Breakdown of agglomerates and aggregates 106
`6.2.4
`Stability to flocculation or colloidal stability 107
`Other considerations 115
`6.3
`References 116
`
`7. A review of liquid mixing equipment 118
`M. F. Edwards and M. R. Baker
`7. 1
`Introduction 118
`7 .2 Mechanically-agitated vessels 119
`7.2.1
`Vessels 119
`7 .2.2
`Baffles 120
`7.2.3
`Impellers 120
`Jet mixers 125
`7.3
`In-line static mixers 126
`7.4
`In-line dynamic mixers 127
`7.5
`7.6 Mills 128
`7.7
`High-speed dispersing units 128
`7.8
`Valve homogenizers 130
`7. 9
`Ultrasonic homogenizers . 130
`7.10 Extruders 132
`7.11 Equipment selection 136
`References 136
`
`8. Mixing of liquids in stirred tanks 137
`M. F. Edwards, M. R. Baker and J. C. Godfrey
`8.1
`Introduction 137
`.
`8.2
`Power input 137
`8.2.1
`Newtonian liquids 137
`8.2.2
`Non-Newtonian liquids 140
`Flow patterns 145
`8.3
`Flow rate-head concepts 147
`8.4
`Turbulence measurements 148
`8.5
`8.6 Mixing time 149
`8.6.1
`Newtonian liquids 151
`8.6.2
`Non-Newtonian liquids 154
`8.7 Mixing efficiency 155
`Notation 156
`References 157
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`9. Jet mixing 159
`B. K. Revill
`9.1
`Introduction 159
`9.2
`Fluid dynamics of turbulent jets 161
`9.3
`Jet mixing in tanks 163
`9.3.l Measurement of mixing time 163
`9.3.2
`Fluid dynamics of jet mixed tanks 164
`9.3.3
`Theoretical prediction of batch mixing time 165
`9.3.4
`Experimental correlations for jet.mixing time 166
`9.3.5
`Recommended jet/tank geometry 170
`9.3.6
`Stratification 172
`9.3.7
`Liquid level variation 174
`9.3.8
`Continuous mixing 174
`9.3.9
`Design procedure 174
`9.3.10 When to use jet mixed tanks 175
`Jet mixing in tubes 177
`9.4.1
`Design basis 177
`9 .4 .2
`Coaxial jet mixer design 178
`9 .4.3
`Side entry jet mixer design 180
`9 .4.4
`Use of tubular jet mixers 180
`Notation 181
`References 182
`
`9.4
`
`10. Mixing in single-phase chemical reactors 184
`J. R. Bourne
`10 .1
`Introduction 184
`10.2 Mechanisms of mixing 184
`10.2.1 Convective, distributive mixing of a single-feed
`stream 185
`Diffusive mixing 188
`Approximate method 189
`More accurate methods 190
`
`10.2.2
`10.2.3
`10.2.4
`Notation 196
`References 198
`
`11. Laminar flow and distributive mixing 200
`M. F. Edwards
`11.1
`Introduction 200
`11.2 Laminar shear 202
`11.3 Elongational (or extensional) laminar flow 210
`11.4 Distributive mixing 214
`11.5 Dispersive mixing in laminar flows 216
`11.6 Applications to blending and dispersing equipment 217
`11. 7 Assessment of mixture quality 222
`Notation 223
`References 224
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`12. Static mixers 225
`J. C. Godfrey
`12.1
`Introduction 225
`12.1. 1 Mixer types 226
`12.2 Laminar mixing 227
`12.2.1 Mixing indices 232
`12.2.2 Mixing rate 234
`12.2.3 Energy and efficiency 238
`12.3 Turbulent mixing 242
`12.3.1 Mixingrate 243
`12.3.2 Energy requirements 245
`12.3.3 Applications 245
`12.4 Conclusions 246
`Notation 247
`References 248
`
`13. Mechanical aspects of mixing 250
`R. King
`13 .1
`Introduction 250
`13.2 The production of 'steady' forces on an agitator and transmission
`of power 251
`13.2.1
`'Steady' forces on an agitator 251
`13.2.2 Transmission of power by an agitator shaft 254
`13.3 The EEUA method of shaft sizing 254
`13.3.1
`Introduction 254
`13.3.2 Combined torsion and bending 256
`13.3.3
`Stress analysis f58
`13.4 Fluctuating forces and vibrations 259
`13.4.l Resonance 259
`13.4.2 Vibrations , 259
`13.4.3 Response to forcing 261
`13.4.4 Fluctuating loads on an agitator shaft 262
`13.4.5 Whirling of the agitator shaft 264
`Shaft design to accommodate fluctuating loads - the FMP
`approach 265
`13.5.l
`Introduction 265
`13.5.2 Sizing the shaft 266
`13.5.3
`Stress analysis 267
`13.6 Fatigue analysis 268
`13.6.1
`Introduction 268
`13.6.2 Bending only 268
`13.6.3 Combined bending and torsion 269
`13.6.4 Checking the safety of the design for fatigue 271
`13.6.5 The importance of a fatigue check 272
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`13.5
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`13.7
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`Seals, gearboxes and impellers 272
`13.7.1
`Seals 272
`13.7.2 Gearboxes 275
`13.7.3
`Impellers 278
`13.8 Economic considerations 279
`13.8.1
`Introduction 279
`13.8.2 Remedial losses 279
`13.8.3 Marketing losses 280
`13.8.4 Examples 280
`13.9 Overall conclusions 283
`Notation 283
`References 285
`Appendix 13.1 Worked examples 286
`
`14. Dynamics of emulsification 294
`D. C. Peters
`14.1
`Introduction 294
`14.2 Rheology and stability 295
`14.3 Droplet formation 300
`14.3.1 . Deformation and breakup in steady flows 301
`14.3.2 Dynamic effects 306
`14.3'.3 Turbulence 306
`Implications for process design 309
`14.4.1 Batch processing 309
`14.4.2 Continuous processing 311
`Notation 311
`References 313
`Appendix 14.1: Numerical example of process design 315
`Appendix 14.2: A procedure for scaling up or down non-Newtonian
`processes 318
`
`14.4
`
`15. Gas-liquid dispersion and mixing 322
`J. C. Middleton
`15. l
`Introduction - classification of gas- liquid mixing problems 322
`15.2 Types and configurations of turbulent gas-liquid stirred
`vessels 326
`15.3 A design basis for gas- liquid agitated vessels 330
`15.4 Power consumption 331
`15.5 Bubble size and coalescence 341
`15.6 Gas hold-up fraction 342
`15.7 Concentration driving force 343
`15.7.1 Liquid mixing 343
`15.7.2 Gas mixing 343
`15.8 Gas-liquid mass transfer 346
`15.9 Heat transfer 349
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`15.10 Gas- liquid mixers as reactors 349
`15.10.1 Theory of mass transfer with reaction 350
`15.10.2 Locale of diffusion limitation 351
`15.10.3 Mixing mode and reaction 352
`15.10.4 Scaleofmixing 353
`15.10.5 Experimental work for classification of reaction
`regimes 354
`15.10.6 Gas-liquid reactor modelling 355
`15 .11 Example of scale-up 357
`Notation 360
`References 361
`
`16. The suspension of solid particles 364
`A. W. Nienow
`16.1
`Introduction 364
`16.2 Definitions of states of suspension and distribution 364
`16.2.1
`Just complete suspension 364
`16.2.2 Homogeneous suspension 365
`16.2.3 Bottom or corner fillets 365
`16.2.4 Dispersion of floating solids 365
`Power consumption in systems with suspended particles 365
`16.3
`16.4 Mechanisms and models of particle suspension and
`distribution 366
`16.4.1
`Particle suspension 366
`16.4.2
`Solids distribution 368
`16.5 Experimental measurement of particle suspension and
`distribution 369
`16.5.1
`Particle distribution 369
`16.5.2
`Just complete suspension speed, NJs 369
`16.6 Experimental results and correlations for NJs 370
`16.6.1
`Introduction 370
`16.6.2 Correlations for N1s 372
`16.6.3
`Particle and fluid properties 373
`16.6.4
`Solid concentration 373
`16.6.5
`Standard geometry 374
`16.6.6 Other geometries 379
`16.6.7
`Scale-up 380
`Selection of geometry and the scale-up rule for (€T) 1s 381
`16.7
`16.8 Solids distribution and withdrawal 382
`16.8.1 Assessment of solids distribution and scale-up 382
`16.8.2 Solid withdrawal 384
`16. 9 Three phase systems 386
`16.10 The ingestion and dispersion of floating solids 388
`16.11 Conclusions 390
`Notation 390
`References 392
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`17. The mixer as a reactor: liquid/solid systems 394
`A . W. Nienow
`17 .1 Reactor types 394
`17 .2 Reaction rates 395
`17 .3 Mass transfer 398
`17 .3.1 Measurement of mass transfer coefficient, k 398
`17.3.2 The relationship between k and impeller speed
`N 399
`k1s at N;s and as a function of (ET)Js 400
`Prediction of the bulk diffusion mass transfer
`coefficient, k 402
`17.3.5 The dissolution time when Sh = 2 406
`17.4 The use of the slip velocity equation 406
`17 .5 Particle impacts and abrasion 407
`17 .6 Conclusions 409
`Notation 409
`References 410
`
`17.3.3
`17 .3.4
`
`Index 412
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`Range of problems
`
`3
`
`When chemical reactions occur between miscible liquids it is necessary to
`bring together the reactants at the molecular level by mixing before the
`reaction can occur. The important interaction between mixing and reaction is
`developed in detail in Cha pter 10.
`
`1.1.3 Solid- liquid mixing
`In operations such as crystallization or solid-catalysed liquid reactions, it is
`nece:)sary to suspend solid particles in a relatively low viscosity liquid. This can
`be achieved in mechanically agitated vessels where the mixer is used to prevent
`sedimentation of the solids ~nd to provide conditions suitable for good liquid(cid:173)
`solid mass transfer and/o r chemical reaction. If agitation is stopped the solids
`will settle out or float to the surface, depending upon the relative densities of
`the solid and liquid phases. T he suspension of solids in mixing vessels and the
`design of mixing vessels for solid- liquid reactions are treated in Chapters 16
`and 17 respectively.
`At the opposite extreme, it may be required to disperse very fine particles
`into a highly viscous liquid. For example, the incorporation of carbon black
`into rubber is such an operation. Here, as with emulsification in liquid- liquid
`mixing, the product is stable, highly viscous and may well exhibit complex
`rheology. Such processes often involve surface phenomena and physical
`contacting only, in contr!lst to the mass transfer and chemical reactions
`described in the previous paragraph. The dispersion of fine particles in liquids
`is considered in detail in Chapter 6.
`
`1.1:4 Gas-liquid mix ing
`
`Several major industrial operations, e.g. oxidation, hydrogenation, and biolo(cid:173)
`gical fe rmentations, involve the contacting of gases and liquids. Often the latter
`are rheologically complex. It is the objective in such processes to agitate the
`gas-liquid mixture in order to generate a dispersion of gas bubbles in a
`continuous liquid phase. Mass transfer then takes place across the gas(cid:173)
`liquid interface which is created. In some instances, chemical reactions
`may also accompany the mass transfer in the liquid phase. These gas dis(cid:173)
`persing duties are similar to the crystallization processes described in solid(cid:173)
`liquid contacting, that is, the term 'mixing' covers a mass-transfer process.
`Furthermore, all the mixtures are unstable and separate if agitation is stopped.
`Gas- liquid contacting involving mass transfer and chemical reaction in
`mixing vessels is considered in Chapter 15.
`In some instances, gases and liquids are mixed to provide a stable batter or
`foam. This contacting is of a physical nature and the resulting product will
`often exhibit non-Newtonian flow characteristics.
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`Other considerations
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`JJ5
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`and operates at short distances. Hence the flocculation behaviour depends on
`the structure of the adsorbed layer (solvency, molecular weight, thickness,
`segment distribution), and the magnitude of the repulsive and/or attractive
`interactions arising from adsorbed layer overlap.
`Significant advances have been made over the last three decades in our
`understanding of steric stabilization, and recently measurements have
`been reported on the force between two surfaces containing adsorbed
`polymer.17..iti. Data on the measurement of the force due to the electrostatic
`interaction of surfaces have also been presented, as well as those arising from
`non-DLVO interactions.
`An interesting example of the applica tion of the concept of steric stabiliza(cid:173)
`tion is the interpretation of the optical performance of alkyd paints pigmented
`with Ti02 by Franklin et al. 32 . Having established from electrophoresis and
`opacity measurements that the electric charge on the particles is not the
`controlling factor in flocculation, a study was made of the adsorption
`characteristics of the resin using pigments coated with different levels of silica/
`alumina such that the surfaces created varied from predominantly silica to
`mostly alumina.
`Interpretation of the adsorption isotherms indicated that for the acidic silica
`surface the basic resin molecules interacted strongly with the surface and
`adopted a parallel orientation, thus making little contribution to preventing
`flocculation. On the other hand, for the predominantly alumina-coated
`surface, the resin only made contact with the surface with its limited number of
`acid groups, the rest of the molecule being extended into the medium and
`providing a steric barrier to flocculation.
`When the surface coverage of polymer is low then 'bridging' flocculation is
`possible. This is brought out by the polymer becoming simultaneously
`adsorbed on two or mo re particles- a 'bridging' mechanism leading to a
`rather open structure in the flocculates. The mechanism has been summarized
`by Kitchener49• Since polymer adsorption is usually irreversible, the method
`of mixing of the components can have a profound effect on the floccu lation
`process. Tadros has reported 50 a good demonstration of the effect, using silica
`and aqueous solutions of polyvinyl alcohol. The effect depends on the
`pretreatment of silica, hence the surface hydroxyl population, and on the pH of
`the solution which determines the particle charge, both factors influencing the
`adsorption sites for PV A adsorption.
`
`6.3 Other considerations
`
`Once dispersion has been achieved, the deflocculatcd particles can be kept in
`suspension by agitation in the mixing vessel. However, once agitation ceases
`sedimentation begins and sediment begins to accumulate. In many cases this is
`unimportant because other components are added either to finish formulating
`the product as for instance in paints, and these give physical stability.
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