Gas Cleaning in Demanding Applications

321 Pages·1997·7.861 MB·English

by  J. P. K. Seville, R. Clift (auth.), Professor J. P. K. Seville (eds.)

Gas Cleaning in Demanding Applications
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Gas Cleaning in Demanding
Applications
Edited by
Professor J. P. K. Seville
School of Chemical Engineering
The University of Birmingham,
UK
Springer-Science+ Business Media, B.V.
First edition 1997
ISBN 978-94-011-7665-1 ISBN 978-94-009-1451-3 (eBook)
DOI 10.1007/978-94-009-1451-3
© 1997 Springer Science+Business Media Dordrecht
Originally published by Chapman & Hali in 1997
Softcover reprint ofthe hardcover 1st edition 1997
Typeset in 10/12pt Times by AFS Image Setters, Glasgow
Apart from any fair dealing for the purposes of research or private study, or
criticism or review, as perrnitted under the UK Copyright Designs and Patents
Act, 1988, this publication may not be reproduced, stored, or transmitted, in
any forrn or by any means, without the prior permission in writing of the
publishers, or in the case of reprographic reproduction only in accordance
with the terms of the licences issued by the Copyright Licensing Agency in
the UK, or in accordance with the terms of licences issued by the appropriate
Reproduction Rights Organization outside the UK. Enquiries concerning
reproduction outside the terrns stated here should be sent to the publishers
at the London address printed on this page.
The publisher makes no representation, express or implied, with regard to
the accuracy of the informati an contained in this book and cannot accept any
legal responsibility or liability for any errors or omissions that may be made.
A catalogue record for this book is available from the British Library
Library of Congress Catalog Card Number: 96-78501
@l Printed on acid-free text pap er, manufactured in accordance with ANSIJNISO
Z39.48-1992 (Permanence of Paper)
Contents
List of contributors xi
Preface xiii
1 Gas cleaning at high temperatures: gas and particle properties 1
J. P. K. Seville and R. Clift
1.1 The need for hot gas cleaning 1
1.2 Gas and particle properties 3
1.2.1 Gas properties 3
1.2.2 Gas-particle interaction 5
1.2.3 Particle-particle interaction 7
References 13
2 Sampling and measurement 15
C. J. Bower
2.1 Fundamental principles 15
2.2 Particulates 16
2.2.1 Standard particulate sampling systems 18
2.2.2 Sampling systems for hot gas streams 20
2.2.3 Alternative dust collection techniques 22
2.2.4 On-line techniques 27
2.3 Alkali metal measurement 30
2.3.1 Batch sampling techniques 32
2.3.2 On-line techniques 34
2.4 Other gaseous contaminants 35
2.4.1 Hydrogen chloride 35
2.4.2 Trace elements 36
2.4.3 Polycyclic aromatic hydrocarbons 37
Acknowledgements 37
References 38
3 Inertial separators: basic principles 41
R. Clift
3.1 Introduction 41
3.2 Analysis of cyclone performance 44
3.2.1 Pressure drop 45
3.2.2 Collection efficiency 46
3.2.3 Cyclone systems 48
3.3 Effects of solids loading 49
3.3.1 Pressure drop 49
3.3.2 Particle capture 49
3.4 Effect of temperature and pressure 50
3.5 Concluding remarks 51
Notation 51
References 52
VI CONTENTS
4 Inertial separators: design and construction for high-temperature
use 53
R. R. Greenfield
4.1 Introduction 53
4.2 Mechanical design 55
4.2.1 Codes 57
4.2.2 Creep 58
4.3 Refractory linings 60
4.4 External cyclones 62
4.5 Heat loss 65
4.6 Conclusions 68
References 69
5 Fabric filters 70
K. Morris and R. W. K. Allen
5.1 Introduction 70
5.2 Fabric filter geometry 70
5.3 Design factors for fabric filters 71
5.3.1 Pressure drop 72
5.3.2 Filtration velocity 73
5.3.3 Filter media 76
5.3.4 Fabric cleaning 80
5.4 Fundamental studies of fabric filtration 83
5.4.1 Filtration 83
5.4.2 Cake adhesion 86
5.4.3 Bag dynamics 86
5.5 Conclusions 94
References 95
6 Rigid ceramic filters 96
J. P. K. Seville
6.1 General features of filtration behaviour 96
6.2 Types of ceramic filtration material 99
6.3 Resistance to flow 102
6.4 Mechanisms of filter cleaning 103
6.4.1 Cake detachment stress 103
6.4.2 Analysis of cleaning by reverse flow or pulse 105
6.4.3 Cake detachment tests 108
6.4.4 Prediction of cake detachment stress Ill
6.5 The relationship between cleaning flow requirement and cycle time 112
6.6 Comparison of filter behaviour 115
6.7 Filter design 118
6.7.1 Candle geometry 118
6.7.2 Candle fixing arrangements 120
6.7.3 Novel medium geometries 124
6.8 Simultaneous removal of solid and gaseous contaminants 125
6.9 Conclusions 126
Acknowledgements 127
Notation 127
References 128
7 Fibrous ceramic filters in industrial use 130
C. J. Withers
7.1 Filtration at high temperature 130
CONTENTS vii
7.2 Ceramic media 131
7.2.1 Types of ceramic medium 131
7.2.2 Properties and benefits 132
7.2.3 Long-term durability 134
7.3 Calculation of required filter size 135
7.3.1 Specification of duty 135
7.3.2 Required results of calculations 136
7.3.3 Intermediate variables 136
7.3.4 Estimating operating parameters 138
7.4 Filter design 140
7.4.1 Horizontal or vertical elements? 140
7.4.2 Reverse pulse cleaning 142
7.4.3 Vessel design 142
7.5 Experiences in industrial applications 145
7.5.1 Combustion 145
7.5.2 Breakage 146
7.5.3 Erosion 146
7.5.4 Sticky dusts 147
7.5.5 Vapour/liquid cycling 147
7.6 Current applications 147
7.7 Future developments 149
7.7.1 Filtration media 149
7.7.2 Applications 149
References 149
8 Granular ceramic filter elements 150
K. Schulz
8.l Introduction 150
8.2 Hot gas filtration technology 151
8.2.1 Surface filtration 151
8.2.2 Pressure drop and permeability 151
8.2.3 On-line cleaning 153
8.2.4 Cake detachment 153
8.2.5 Filtration efficiency 154
8.3 Silicon carbide-based hot gas filter elements 158
8.3.1 Material description 158
8.3.2 Material properties 160
8.4 Hot gas filter systems 162
8.4.1 Design of hot gas filters 162
8.4.2 Venturi ejector design 162
8.5 Applications 166
Acknowledgements 168
References 168
9 Granular bed filters 170
J. P. K. Seville and R. Clift
9.l Introduction 170
9.2 Collection 171
9.3 Retention 177
9.4 Cake formation 179
9.5 Fl uidised bed filters 179
9.6 Design 182
References 190
Vlll CONTENTS
10 Electrostatic precipitation 193
C. Riehle
10.1 Introduction 193
10.2 Fundamentals 193
10.2.1 Effect of high temperature and/or high pressure 193
10.2.2 Minimum field strength for corona initiation 197
10.2.3 Tube-type ESP 198
10.2.4 Particle charging process 203
10.2.5 Migration velocity 205
10.2.6 Grade efficiency 210
10.2.7 Particle resistivity 212
10.3 HTHP design 215
10.3.1 Examples 215
10.3.2 Problems 219
10.4 Conclusions 224
Notation 227
References 228
11 Dry scrubbing 229
W.Duo
11.1 Introduction 229
11.2 Fundamentals of gas-solid reactions 230
11.2.1 Thermodynamics 230
11.2.2 Kinetic experiments 233
11.2.3 Formation of product layers 238
11.3 Mathematical modelling 242
11.3.1 Shrinking unreacted core model 242
11.3.2 Grain model 244
11.3.3 Grain-micrograin model 246
11.3.4 Single-pore model 247
11.3.5 Distributed-pore model 247
11.4 Applications 247
11.4.1 Entrained flow reactor 248
11.4.2 Fluidised bed 248
11.4.3 Filter cake 249
11.4.4 Semi-dry scrubbing 253
Acknowledgements 254
Notation 254
References 256
12 Condensable components 259
R. Clift and I. Fantom
12.1 Introduction 259
12.2 Volatility and the effect of chlorine 260
12.3 Alkali removal using 'getters' 264
12.4 Alkali removal by condensation and filtration 267
Appendix: thermodynamic equilibrium 269
References 270
13 Wet scrubbing 272
A. Arrowsmith and N. F. Ashton
13.1 Theoretical aspects 272
CONTENTS ix
13.2 Randomly packed columns 275
13.2.1 Hydrochloric acid storage tank vent scrubbers 275
13.2.2 By-product recovery 278
13.2.3 Acid aerosols 279
13.3 Plate scrubbers 282
13.3.1 Aluminium furnace fines treatment 284
13.4 Fluidised-bed scrubbing 285
13.5 Wet catalytic oxidation 287
13.5.1 Process description 289
13.5.2 Pilot-scale data 290
13.5.3 Case study 292
13.6 Absorption of VOCs with 'designer solvents' 292
13.6.1 Theoretical considerations 294
13.6.2 Selection of the absorbent 295
13.6.3 Process characteristics 295
13.7 Biological scrubbers 300
13.7 .1 Press house gas treatment 301
13.7.2 Biological oxidation 302
Acknowledgements 302
References 303
Index 305