Applied Chemical Process Design

298 Pages·1978·18.967 MB·English

by  Frank Aerstin, Gary Street (auth.)

Applied Chemical Process Design
Applied Chemical Process Design
FRANK AERSTIN AND GARY STREET
Dow Chemical
Midland, Michigan
With a Foreword by
K. D. Timmerhaus
PLENUM PRESS • NEW YORK AND LONDON
Library of Congress Cataloging in Publication Data
Aerstin, Frank.
Applied chemical process design.
Includes index.
1. Chemical processes. 2. Chemical engineering. I. Street, Gary, joint
author. II. Title.
TP 155.7 .A35 660.2'81 78-9104
ISBN-13:978-1-4613-3978-6 e-ISBN -13 :978-1-4613-3976-2
DOI: 10.1007/978-1-4613-3976-2
First Printing-November 1978
Second Printing - May 1980
Third 'Printing - January 1982
Fourth Printing-October 1989
© 1978 Plenum Press, New York
Softcover reprint of the hardcover 1st edition 1978
A Division of Plenum Publishing Corporation
233 Spring Street, New York, N.Y. 10013
All rights reserved
No part of this book may be reproduced, stored in a retrieYaI system, or transmitted,
in any form or by any means electronic, mechanical, photocopying, microfJiming,
recording, or otherwise, without written permission from the Publisher
Contents
Foreword ........................................... . vii
Preface ............................................. . ix
List of Figures ...................................... . xi
List of Tables ....................................... . xv
Conversion Tables ................................... . 1
1. Agitation and Mixing ................................ . 9
1.1. Agitators •.••••.•••.•••..••••••.•••••••••••.•..••.. 9
1.2. Motionless Mixers .•.•.••...•.•.•...•...•..•.•..•••.. 12
2. Cooling Towers ................... ~ ................. . 29
3. Decanters .......................................... . 35
4. Distillation .......................................... . 39
4.1. Basic Laws ••..••••••.••••••.••••••.•••••••••..•••• 39
4.2. Shortcut Method-Optimum Trays and Optimum
Reflux Ratio •..••••••••••••••.•••••••••••••••••••••. 39
4.3. Flash Vaporization •..•••..•.•.•.••••••.•.•••.•.•.•.•. 47
4.4. Selection of Internals •.•••••••••••••••..••••.••.•.•••• 49
4.5. Tray Column Diameter ••••••••••.•••••••.••••.•••..••• 49
4.6. Tray Overall Efficiency ••••••.••••••••••••••••••••..••• 50
51
4.7. Packed Column Design •••••.••••••••..••••••••.••.•••
4.8. Packed Column Diameter and Pressure Drop ..••.••••.....• 53
5. Economic Evaluation ................................ . 57
6. Fluid Flow .......................................... . 65
6.1. Fluid Flow-Single Phase ••••.•••.••••••.•.•••••••.•••• 65
6.2. Fluid Flow-Two Phase ••••••••••••••••.•••••••••.•••. 92
6.3. Flow through Orifices 96
7. Gas-Solid Separations .................. , ............ . 105
8. Heat Transfer ....................................... . 111
111
8.1. Heat Transfer Coefficients •••••••••.•••..•••••.•••.••••
121
8.2. Heat Losses from Tanks •.••..• : .•••.•...••..........•.
8.3. Heating of Process Piping and Vessels-Heat Losses
from Insulated Pipelines •••••..•••.••••.•.•••••••.••••• 121
8.4. Heating of Process Piping and Vessels-Steam
121
Tracing •••••.••••••••••.•••.•.•••••••••.•••..••.•.
V
vi
CONTENTS
B.5. Heating of Process Piping and Vessels-Dowtherm
SR-1 Tracing ••••••••••.••••••••••••••••••••••••••• 124
B.6. Double Pipe Exchangers •••••••••••••••••••••••••••••• 128
B.7. Shell and Tube Heat Exchangers ...•..•••••.••••.•.•••• 132
B.B. Heat Transfer Coefficient in Agitated Vessels ••••••.•..••. 144
B.9. Falling Film Coefficients ...•....................•...•. 145
B.10. Reboilers and Vaporizers ..••••......••••••..•..••.••• 146
B.11. Condensers ••••••••••.•••••••••••••••••••••••••••• 154
B.12. Air-Cooled Heat Exchangers •••••••••.••••••••••.•••••• 158
B.13. Unsteady-State Heat Transfer ••••••••••••••••••••••••• 170
9. Hydroclones ......................................... 181
10. Materials ............................................ 185
11. Physical Properties ................................... 189
12. Dimensions and Properties of Piping ................... 231
13. Pump Sizing ......................................... 235
14. Safety Relief Valves and Rupture Disks .....•....•..... 243
15. Steam Ejectors for Vacuum Service .................... 257
16. Tank Capacity ........................................ 269
17. Dimensions and Properties of Steel Tubing.... ......... 275
18. Vapor-Liquid Separators .............................. 277
19. Vessel Design ........................................ 283
Index ........................................... 291
Foreword
Development of a new chemical plant or process from concept evaluation
to profitable reality is often an enormously complex problem. Generally,
a plant-design project moves to completion through a series of stages
which may include inception, preliminary evaluation of economics and
market, data development for a final design, final economic evaluation,
detailed engineering design, procurement, erection, startup, and pro
duction.
The general term plant design includes all of the engineering aspects
involved in the development of either a new, modified, or expanded
industrial plant. In this context, individuals involved in such work will be
making economic evaluations of new processes, designing individual pieces
of equipment for the proposed new ventures, or developing a plant layout
for coordination of the overall operation. Because of the many design
duties encountered, the engineer involved is many times referred to as a
design engineer. If the latter specializes in the economic aspects of the
design, the individual may be referred to as a cost engineer. On the other
hand, if he or she emphasizes the actual design of the equipment and
facilities necessary for carrying out the process, the individual may be
referred to as a process design engineer. The material presented in this
book is intended to aid the latter in developing rapid chemical designs
without becoming unduly involved in the often complicated theoretical
underpinnings of these useful notes, charts, tables, and equations.
The authors have attempted to emphasize those areas most often
encountered in chemical process design, namely heat transfer, mass
transfer, fluid flow, and mixing. Other design areas considered, but to a
lesser extent, include cooling towers, liquid-liquid separations, gas-solid
separations, vapor-liquid separations, pumps, safety valves and rupture
disks, steam ejectors, and vessel design. These design procedures are sup
plemented with information on the thermal and transport properties of
many materials and chemicals needed in the design of such process equip
ment, the mechanical properties of a host of metals commonly used in
their construction, and the dimensions and properties of steel piping and
tubing. In addition, two measures of economic profitability have been
included to assist the process design engineer in justifying a specific design
or process to management.
vii
Preface
Applied Chemical Process Design was prepared to give the chemical process
engineer a ready reference that can be used at the office, in the field, or
while on business travel.
After spending several years in the chemical industry, we had found
that each of us had a rather scattered collection of useful notes, charts,
tables, articles, etc. The need to organize and consolidate these references
was obvious.
This book has been intentionally kept concise, to maintain its useful
ness while in the field. Theory has been virtually eliminated. However, the
material presented is adequate to solve many design and/or plant problems.
Those wishing to learn more of the background or theory behind the meth
ods presented should consult the references and selected readings given at
the end of each chapter.
The areas given the highest priority are those encountered most often:
agitation, distillation, heat transfer, and fluid flow.
The book is intended to help students, process design engineers, pilot
plant engineers, and production engineers. It is hoped that it will be of
particular value to younger engineers in bridging the gap between theory
and application.
Acknowledgments
We would like to express our thanks to our colleagues at Dow Chemical,
USA, whose constructive comments have been very helpful. In partic
ular, the help of Lanny Robbins, Bruce Lovelace, Clarence Voelker, James
Huff, Gerald Geyer, Douglas Leng, Thomas Tefft, Leo Schick, Jay Bleiweiss,
James May, Paul Handt, and Kenneth Coulter has been appreciated. We
would also like to thank Dr. James Pfafflin (Stevens Institute of Technol
ogy) and Dr. Harold Donnelly (Wayne State University) for their comments
and help. Finally, we would like to thank the department secretaries (Susan
Krantz, Erna Nash, Barbara Talicska, Anne Marie Duranczyk, and Nancy
Roop), whose patience and perseverance have been greatly appreciated.
Frank Aerstin
Gary Street
IX
Figures
Figure 1.1. Tank and agitator dimensions . . . . . . . . . . . . . . . . . . . 10
Figure 1.2. Turbine power correlations .................... 11
Figure 1.3. Power correlations for glassed steel agitators ....... 12
Figure 1.4. "A" factor vs. Reynolds number in the laminar flow
region ..................................... 15
Figure 1.5. "E" factor vs. Reynolds number in the turbulent flow
region ..................................... 15
Figure 1.6. Darcy's friction chart ......................... 17
Figure 1.7. LPD laminar flow ............................ 19
Figure 1.8. ISG laminar flow ............................ 20
Figure 1.9. LPD turbulent flow .......................... 21
Figure 1.10. ISG turbulent flow ........................... 22
Figure 1.11. Parameters for pressure drop in liquid-gas flow ..... 23
Figure 2.1. Cooling tower performance curves ............... 30
Figure 2.2. Induced draft cooling tower sizing curve .......... 31
Figure 2.3. Typical parts and framing for a crossflow cooling
tower ..................................... 32
Figure 3.1. Decanter piping ............................. 36
Figure 3.2. Sizing discharge piping from gravity decanters ...... 36
Figure 3.3. Liquid-liquid gravity decanter with circular overflow
weirs and adjustable interface position ............ 37
Figure 4.1. Fenske equation for minimum plates ............. 41
Figure 4.2. Relation between optimum-to-minimum ratio and
Fenske separation factor of aavg values ........... 41
Figure 4.3. Optimum-minimum reflux ratio relationship to the
column's feed, distillate, and bottoms composition .. 42
Figure 4.4. Underwood's (J vs. key ratios in feed ............. 43
Figure 4.5. Underwood's (J vs. (a - (J)/a for a in range of
1.01-1.11 .................................. 44
Figure 4.6. Underwood's (J vs. (a - (J)/a for a in range of
1.05-3.00 .................................. 45
Figure 4.7. Underwood's (J vs. (a - (J)/a for heavy key and
heavier components .......................... 46
xi
XII FIGURES
Figure 4.8. Effect of thermal condition of feed on feed tray
location ................................... 47
Figure 4.9. Capacity parameter for column diameter .......... 50
Figure 4.10. Tray overall efficiency ........................ 51
Figure 4.11. Generalized pressure drop correlation in packed
towers .................................... 52
Figure 6.1. Correction for pressure drop due to viscosity and
density .................................... 74
Figure 6.2. Pressure drop and flow velocity of water in
plastic-lined pipe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
Figure 6.3. Viscosity vs. minimum flow to produce turbulent
flow ...................................... 75
Figure 604. Pressure drop for gas flow ..................... 78
Figure 6.5. Pressure drop for gas flow ..................... 79
Figure 6.6. Steam flow chart ............................ 80
Figure 6.7. Fanning friction factor for pipe flow ............. 82
Figure 6.8. Sizing chart for pipe handling liquids in vertical
down flow .................................. 83
Figure 6.9. Basis for Lapp1e charts ........................ 86
Figure 6.10. Lapple charts for compressible flow .............. 87
Figure 6.11. Flow curves for Parshall flumes ................. 88
Figure 6.12. Composite sketch of small Parshall flume . . . . . . . . . . 89
Figure 6.13. Composite sketch of large Parshall flume .......... 90
Figure 6.14. Curves showing relation between 1>1> 1>g, Rio and Rg
for all flow mechanisms ....................... 93
Figure 6.15. Flow coefficient for square-edged orifices ......... 96
Figure 6.16. Net expansion factor Y for compressible flow
through nozzles and orifices .................... 97
Figure 7.1. Particle size classification ...................... 106
Figure 7.2. Particle classification and useful collection equipment
vs. particle size .............................. 107
Figure 7.3. Efficiency curves for various types of dust-collecting
equipment ................................. 108
Figure 704. Cyclone sizing ......... . . . . . . . . . . . . . . . . . . . .. 109
Figure 8.1. Flow of heat through tube walls .. . . . . . . . . . . . . . .. 112
Figure 8.2. Effect of velocity on heat transfer rates ........... 113
Figure 8.3. Heat supplied by 150 psig steam tracer ........... 122
Figure 804. Heat supplied by Dowtherm SR-l tracer .......... 125
Figure 8.5. Tube side heat transfer ........................ 131
Figure 8.6. Shell side heat transfer curve for segmental baffles ... 137
Figure 8.7. Film coefficients for water in tubes .............. 138
xiii
FIGURES
Figure 8.8. Tube side friction factors ..................... . 139
Figure 8.9. Tube side and return pressure drop per tube pass ... . 140
Figure 8.1 O. Shell side friction factors for low-finned and plain
tubes .................................... . 141
Figure 8.11. LMTD correction factor F, 1-2 exchangers ....... . 142
Figure 8.12. LMTD correction factor F, 2-4 exchangers ....... . 143
Figure 8.13. Natural circulation boiling and sensible film
coefficients ................................ . 147
Figure 8.14. Vertical thermosiphon reboiler connected to tower .. 148
Figure 8.15. Condenser performance chart .................. . 155
Figure 8.16. Condensing film coefficients 156
Figure 8.17. Condensation in vertical tubes ................. . 156
Figure 8.18. Condenser for material low in light ends ......... . 157
Figure 8.19. Condensation curve for Figure 8.18 ............. . 157
Figure 8.20. Condenser for material with broad condensing curve . 157
Figure 8.21. Condensation curve for Figure 8.20 ............. . 158
Figure 8,.22. Service coefficient vs. outlet viscosity for natural gas
and refinery liquid streams .................... . 159
Figure 8.23. Required surface area for air-cooled heat exchangers
as a function of the number of rows, overall U,
approach, and cooling range ................... . 161
tt
Figure 8.24. Curve to find 2 /MMBtu/hr for example problem .. . 169
Figure 9.1. Cyclone design and flow patterns ............... . 182
Figure 11.1. Viscosities of liquids ......................... . 213
Figure 11.2. Viscosities of gases .......................... . 215
Figure 11.3. Refrigerant properties ....................... . 222
Figure 11.4. Specific heats of liquids ...................... . 226
Figure 11.5. Specific heats of gases at l-atm pressure .......... . 227
Figure 11.6. Latent heats of vaporization ................... . 228
Figure 13.1. Pump calculation sheet ....................... . 236
Figure 13.2. Viscosity correction chart (10-100 gpm) ......... . 238
Figure 13.3. Viscosity correction chart (100-10,000 gpm) ..... . 239
Figure 14.1. Conventional relief valve ...................... 244
Figure 14.2. Balanced bellows relief valve ................... 245
Figure 14.3. Comparison of a balanced bellows valve and a
conventional valve ........................... 246
Figure 14.4. Cvs. specific heat ratio k ...................... 247
Figure 14.5. Variable or constant backpressure sizing factor Ky;
10% overpressure ............................ 249
Figure 14.6. Variable or constant backpressure sizing factor Ky;
20% overpressure ............................ 250