Forsthoffer's Rotating Equipment Handbooks, Vol. 3: Compressors (Forsthoffer's Rotating Equipment Handbooks)

435 Pages·2006·20.55 MB·English

by  William Forsthoffer

Forsthoffer's
Rotating
Equipment
Handbooks
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Forsthoffer's
Rotating
Equipment
Handbooks
Volume 3: Compressors
W E (Bill) Forsthoffer
President, Forsthoffer Associates
Washington Crossing, PA, USA
ELSEVIER
UK Elsevier Ltd, The Boulevard, Langford Lane, Kidlington, Oxford OX5 1GB,
UK
USA Elsevier Inc, 360 Park Avenue South, New York, NY 10010-1710, USA
JAPAN Elsevier Japan, Tsunashima Building Annex, 3-20-12 Yushima, Bunkyo-ku,
Tokyo 113, Japan
Copyright © 2005 W E Forsthoffer. Published by Elsevier Ltd. All rights reserved.
ISBN 1-85617-469-7
All rights reserved. No part of this publication may be reproduced, stored in a retrieval
system or transmitted in any form or by any means: electronic, electrostatic, magnetic
tape, mechanical, photocopying, recording or otherwise, without permission in writing
from the publishers.
British Library Cataloguing in Publication Data
A CIP Catalogue record for this book is available from the British Library
No responsibility is assumed by the Author or Publisher for any injury and/or damage to
persons or property as a matter of products liability, negligence or otherwise, or from any
use or operation of any methods, products, instructions or ideas contained in the material
herein.
Published by
Elsevier Advanced Technology,
The Boulevard, Langford Lane, Kidlington, Oxford OX5 1GB, UK
Tel:-H44(0) 1865 843000
Fax:-h44(0) 1865 843971
Typeset by Land & Unwin Ltd., Northamptonshire
Printed and bound in Great Britain by MPG Books Ltd, Bodmin, Cornwall
Contents
Preface
Xlll
Acknowledgements
XV
About the author xvii
1 Rotating equipment overview
Introduction I
Definition of rotating equipment I
Classifications of rotating equipment 3
Site equipment examples 4
Performance and mechanical design similarities 6
The equipment 'train' or 'unit' 8
Important fundamentals 9
2 Compressor types and applications 13
Introduction 13
Positive displacement compressors 15
Dynamic compressors 21
3 Compressor characteristics 29
Inroduction 29
Positive displacement compressors 31
Actual volume, standard volume and mass flow 33
Dynamic compressors 36
4 Operation of a compressor in a system 43
Introduction 43
The definition of a process system 45
System resistance curves 46
The operating point 49
A positive displacement compressor in the process system 50
A dynamic compressor in the process system 50
5 The concept of fluid head 53
Introduction 53
Definition 54
Paths of compression 59
The different types of gas head 59
Dynamic compressor curves format 62
6 Performance relationships 63
Introduction 63
Satisfying the objective 64
Gas characteristics 65
Compression head 67
Impeller types and specific speed 67
Efficiency 70
Horsepower 71
The Fan Laws 72
7 What determines the turbo-compressor curve shape 73
Introduction 73
The compressor stage 73
Impeller with side plate removed 75
Impeller discharge velocities 77
Blading types 79
8 Surge (stall) and stonewall 83
Introduction 83
Surge facts 85
The limits of the curve 87
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What causes surge 88
What causes stonewall (choke) 91
9 Turbo-compressor individual stage and overall
performance 95
Introduction 95
The stage curve 97
The overall curve 98
Determining section performance 100
10 The effect of a gas density change 103
Introduction 103
The factors involved 105
The effect on turbo-compressor pressure ratio 106
The effect on the compressor head 106
The effect on system resistance 109
The effect on turbo-compressor flow rate 109
The effect on power 110
11 The effect of fouling 113
Introduction 113
The mechanism of fouling 113
The effect of fouling on the operating point 114
The causes of fouling 117
Detecting fouling by condition monitoring 119
Preventing and correcting fouling 120
Corrective measures 123
12 Turbo-compressor control overview 125
Introduction 125
The objectives 127
Adjusting to system changes 128
Adjusting the turbo-compressor performance curve 130
Turbo-compressor protection 133
Contents mmmmmmmmaammmmmmmammmmm^
13 Surge control systems 137
Introduction 137
System objectives 137
Available options 138
System design considerations 139
A history of system types 139
14 Turbo-compressor mechanical design overview 143
Introduction 143
The casing 145
The inlet guide vanes 146
The rotor 147
Diaphragms 148
Inter-stage seals 149
Shaft end seals 150
Journal bearings 153
Thrust bearings 154
15 Compressor casings and stationary internals 159
Introduction 159
Casing functions 160
Casing types 161
Casing fabrication options 165
Casing stresses and deflections 166
16 Centrifugal compressor rotor design 169
Introduction 169
Shaft end design 170
Rotor stiffness 172
Basic rotor configurations 172
Rotor assembly 173
Rotor balance 176
VIM
17 Flexible coupling design, installation and operation 179
Introduction 179
The coupling function 179
180
Types
The coupling system 188
Coupling installation and removal 191
Enclosed coupling guards 194
Field retrofits from lubricated to dry couplings 195
18 Radial bearing design 197
Introduction 197
Anti-friction bearings 198
Hydrodynamic bearings 200
Hydrodynamic bearing types 202
Condition monitoring 205
Vibration instabilities 207
19 Critical speeds and rotor response 213
Introduction 213
Critical speeds 2 14
The rotor system (input) 217
Rotor response (output) 220
Measured rotor response 224
20 Rotor axial (thrust) forces 225
Introduction 225
The hydrodynamic thrust bearing 226
Impeller thrust forces 230
Rotor thrust balance 231
Thrust condition monitoring 233
21 Compressor seal system overview and types 237
Introduction 237
The supply system 24 1
The seal housing system 242
Seal supply systems 249
Seal supply system summary 256
Seal liquid leakage system 256