applied process design for chemical and petrochemical plants - vol 3

APPLIED
PROCESS
DESIGN
FOR CHEMICAL AND PETROCHEMICAL PLANTS
Volume 3, Third Edition
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Volume 1: 1. Process Planning, Scheduling, Flowsheet Design
2. Fluid Flow
3. Pumping of Liquids
4. Mechanical Separations
5. Mixing of Liquids
6. Ejectors
7. Process Safety and Pressure-Relieving Devices
Appendix of Conversion Factors
Volume 2: 8. Distillation
9. Packed Towers
Volume 3: 10. Heat Transfer
11. Refrigeration Systems
12. Compression Equipment (Including Fans)
13. Reciprocating Compression Surge Drums
14. Mechanical Drivers
ii
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APPLIED
PROCESS
DESIGN
FOR CHEMICAL AND PETROCHEMICAL PLANTS
Volume 3, Third Edition
Ernest E. Ludwig
Retired Consulting Engineer
Baton Rouge, Louisiana

Boston Oxford Auckland Johannesburg Melbourne New Delhi
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Foreword to the Second Edition ix
Preface to the Third Edition xi
10. Heat Transfer 1
Types of Heat Transfer Equipment Terminology,
1; Details of Exchange Equipment Assembly and
Arrangement, 8; 1. Construction Codes, 8; 2. Ther-
mal Rating Standards, 8; 3. Exchanger Shell Types,
8; 4. Tubes, 10; 5. Baffles, 24; 6. Tie Rods, 31; 7.
Tubesheets, 32; 8. Tube Joints in Tubesheets, 34
Example 10-1. Determine Outside Heat Transfer
Area of Heat Exchanger Bundle, 35; Tubesheet
Layouts, 35; Tube Counts in Shells, 35; Exchanger
Surface Area, 50; Effective Tube Surface, 51;
Effective Tube Length for U-Tube Heat Exchang-
ers, 51; Example 10-2. Use of U-Tube Area Chart,
51; Nozzle Connections to Shell and Heads, 53;
Types of Heat Exchange Operations, 53; Thermal
Design, 53; Temperature Difference: Two Fluid
Transfer, 55; Mean Temperature Difference or
Log Mean Temperature Difference, 57; Example
10-3. One Shell Pass, 2 Tube Passes Parallel-Coun-
terflow Exchanger Cross, After Murty, 57; Exam-
ple 10-4. Performance Examination for Exit
Temperature of Fluids, 72; Correction for Multi-
pass Flow through Heat Exchangers, 72; Heat
Load or Duty, 74; Example 10-5. Calculation of
Weighted MTD, 74; Example 10-6. Heat Duty of a

Condenser with Liquid Subcooling, 74; Heat Bal-
ance, 74; Transfer Area, 75; Example 10-7. Calcu-
lation of LMTD and Correction, 75; Temperature
for Fluid Properties Evaluation — Caloric Tem-
perature, 75; Tube Wall Temperature, 76; Fouling
of Tube Surface, 78; Overall Heat Transfer Coef-
ficients for Plain or Bare Tubes, 87; Approximate
Values for Overall Coefficients, 90; Example 10-8.
Calculation of Overall Heat Transfer Coefficient
from Individual Components, 90; Film Coeffi-
cients with Fluid Inside Tubes, Forced Convection,
94; Film Coefficients with Fluids Outside Tubes,
101; Forced Convection, 101; Shell-Side Equiva-
lent Tube Diameter, 102; Shell-Side Velocities, 107;
Design Procedure for Forced Convection Heat
Transfer in Exchanger Design, 109; Example 10-9.
Convection Heat Transfer Exchanger Design, 112;
Spiral Coils in Vessels, 116; Tube-Side Coefficient,
116; Outside Tube Coefficients, 116; Condensa-
tion Outside Tube Bundles, 116; Vertical Tube
v
Bundle, 116; Horizontal Tube Bundle, 119; Step-
wise Use of Devore Charts, 121; Subcooling, 122;
Film Temperature Estimation for Condensing,
123; Condenser Design Procedure, 123; Example
10-10. Total Condenser, 124; RODbaffled® (Shell-
Side) Exchangers, 129; Condensation Inside
Tubes, 129; Example 10-11. Desuperheating and
Condensing Propylene in Shell, 134; Example 10-
12. Steam Heated Feed Preheater—Steam in

Shell, 138; Example 10-13. Gas Cooling and Partial
Condensing in Tubes, 139; Condensing Vapors in
Presence of Noncondensable Gases, 143; Example
10-14. Chlorine-Air Condenser, Noncondensables,
Vertical Condenser, 144; Example 10-15. Con-
densing in Presence of Noncondensables, Col-
burn-Hougen Method, 148; Multizone Heat
Exchange, 154; Fluids in Annulus of Tube-in-Pipe
or Double Pipe Exchanger, Forced Convection,
154; Approximation of Scraped Wall Heat Trans-
fer, 154; Heat Transfer in Jacketed, Agitated Ves-
sels/Kettles, 156; Example 10-16. Heating Oil
Using High Temperature Heat Transfer Fluid,
157; Pressure Drop, 160; Falling Film Liquid Flow
in Tubes, 160; Vaporization and Boiling, 161;
Vaporization in Horizontal Shell; Natural Circula-
tion, 164; Vaporization in Horizontal Shell; Nat-
ural Circulation, 165; Pool and Nucleate Boiling
— General Correlation for Heat Flux and Critical
Temperature Difference, 165; Reboiler Heat Bal-
ance, 168; Example 10-17. Reboiler Heat Duty
after Kern, 169; Kettle Horizontal Reboilers, 169;
Nucleate or Alternate Designs Procedure , 173;
Kettle Reboiler Horizontal Shells, 174; Horizontal
Kettle Reboiler Disengaging Space, 174; Kettel
Horizontal Reboilers, Alternate Designs, 174;
Example 10-18. Kettle Type Evaporator — Steam
in Tubes, 176; Boiling: Nucleate Natural Circula-
tion (Thermosiphon) Inside Vertical Tubes or
Outside Horizontal Tubes, 177; Gilmour Method

Modified, 178; Suggested Procedure for Vaporiza-
tion with Sensible Heat Transfer, 181; Procedure
for Horizontal Natural Circulation Thermosiphon
Reboiler, 182; Kern Method, 182; Vaporization
Inside Vertical Tubes; Natural Thermosiphon
Action, 182; Fair’s Method, 182; Example 10-19.
C3 Splitter Reboiler, 194; Example 10-20. Cyclo-
hexane Column Reboiler, 197; Kern’s Method
Stepwise, 198; Other Design Methods, 199; Exam-
ple 10-21. Vertical Thermosiphon Reboiler, Kern’s
Method, 199; Simplified Hajek Method—Vertical
Thermosiphon Reboiler, 203; General Guides for
Vertical Thermosiphon Reboilers Design, 203;
Example 10-22. Hajek’s Method—Vertical Ther-
Contents
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mosiphon Reboiler, 204; Reboiler Piping, 207;
Film Boiling, 207; Vertical Tubes, Boiling Outside,
Submerged, 207; Horizontal Tubes: Boiling Out-
side, Submerged, 208; Horizontal Film or Cascade
Drip-Coolers—Atmospheric, 208; Design Proce-
dure, 208; Pressure Drop for Plain Tube Exchang-
ers, 210; A. Tube Side, 210; B. Shell Side, 211;
Alternate: Segmental Baffles Pressure Drop, 215;
Finned Tube Exchangers, 218; Low Finned Tubes,
16 and 19 Fins/In., 218; Finned Surface Heat
Transfer, 219; Economics of Finned Tubes, 220;
Tubing Dimensions, Table 10-39, 221; Design for
Heat Transfer Coefficients by Forced Convection
Using Radial Low-Fin tubes in Heat Exchanger

Bundles, 221; Design Procedure for Shell-Side
Condensers and Shell-Side Condensation with
Gas Cooling of Condensables, Fluid-Fluid Convec-
tion Heat Exchange, 224; Design Procedure for
Shell-Side Condensers and Shell-Side Condensa-
tion with Gas Cooling of Condensables, Fluid-
Fluid Convection Heat Exchange, 224; Example
10-23. Boiling with Finned Tubes, 227; Double
Pipe Finned Tube Heat Exchangers, 229; Miscella-
neous Special Application Heat Transfer Equip-
ment, 234; A. Plate and Frame Heat Exchangers,
234; B. Spiral Heat Exchangers, 234; C. Corru-
gated Tube Heat Exchangers, 235; D. Heat Trans-
fer Flat (or Shaped) Panels, 235; E. Direct Steam
Injection Heating, 236; F. Bayonet Heat Exchang-
ers, 239; G. Heat-Loss Tracing for Process Piping,
239; Example 10-24. Determine the Number of
Thermonized® Tracers to Maintain a Process Line
Temperature, 243; H. Heat Loss for Bare Process
Pipe, 245; I. Heat Loss through Insulation for
Process Pipe, 246; Example 10-25. Determine Pipe
Insulation Thickness, 248; J. Direct-Contact Gas-
Liquid Heat Transfer, 249; Example 10-26. Deter-
mine Contact Stages Actually Required for Direct
Contact Heat Transfer in Plate-Type Columns,
251; General Application, 259; Advantages—
Air-Cooled Heat Exchangers, 260; Disadvantages,
260; Bid Evaluation, 260; Design Considerations
(Continuous Service), 263; Mean Temperature
Difference, 267; Design Procedure for Approxi-

mation, 269; Tube-Side Fluid Temperature Con-
trol, 271; Heat Exchanger Design with Computers,
271; Nomenclature, 273; Greek Symbols, 278; Sub-
scripts, 279; References, 279; Bibliography, 285
11. Refrigeration Systems 289
Types of Refrigeration Systems, 289; Terminology,
289; Selection of a Refrigeration System for a
Given Temperature Level and Heat Load, 289;
Steam Jet Refrigeration, 290; Materials of Con-
struction, 291; Performance, 291; Capacity, 293;
Operation, 295; Utilities, 295; Specification, 296;
vi
Example 11-1. Barometric Steam Jet Refrigera-
tion, 299; Absorption Refrigeration, 299; Ammo-
nia System, 299; General Advantages and Features,
301; Capacity, 301; Performance, 301; Example 11-
2. Heat Load Determination for Single-Stage
Absorption Equipment, 302; Lithium Bromide
Absorption for Chilled Water, 305; Mechanical
Refrigeration, 308; Compressors, 309; Con-
densers, 311; Process Evaporator, 311; Compres-
sors, 311; Purge, 312; Process Performance, 312;
Refrigerants, 312; ANSI/ASHRAE Standard 34-
1992, “Number Designation and Safety Classifica-
tion of Refrigerants”, 312; System Performance
Comparison, 319; Hydrocarbon Refrigerants, 321;
Example 11-3. Single-Stage Propane Refrigeration
System, Using Charts of Mehra, 322; Example 11-
4. Two-Stage Propane Refrigeration System, Using
Charts of Mehra, 328; Hydrocarbon Mixtures and

Refrigerants, 328; Liquid and Vapor Equilibrium,
333; Example 11-5. Use of Hydrocarbon Mixtures
as Refrigerants (Used by Permission of the Car-
rier Corporation.), 333; Example 11-6. Other Fac-
tors in Refrigerant Selection Costs, 350; System
Design and Selection, 353; Example 11-7. 300-Ton
Ammonia Refrigeration System, 353; Receiver,
359; Example 11-8. 200-Ton Chloro-Fluor-Refrig-
erant-12, 361; Economizers, 361; Suction Gas
Superheat, 362; Example 11-9. Systems Operating
at Different Refrigerant Temperatures, 362; Com-
pound Compression System, 363; Comparison of
Effect of System Cycle and Expansion Valves on
Required Horsepower, 363; Cascade Systems, 363;
Cryogenics, 364; Nomenclature, 365; Subscripts,
366; References, 366; Bibliography, 366
12. Compression Equipment
(Including Fans) 368
General Application Guide, 368; Specification
Guides, 369; General Considerations for Any Type
of Compressor Flow Conditions, 370; Reciprocat-
ing Compression, 371; Mechanical Considera-
tions, 371; Performance Considerations, 380;
Specification Sheet, 380; Compressor Perfor-
mance Characteristics, 410; Example 12-1. Inter-
stage Pressure and Ratios of Compression, 415;
Example 12-2. Single-Stage Compression, 430;
Example 12-3. Two-Stage Compression, 431; Solu-
tion of Compression Problems Using Mollier Dia-
grams, 433; Horsepower, 433; Example 12-4.

Horsepower Calculation Using Mollier Diagram,
433; Cylinder Unloading, 442; Example 12-5.
Compressor Unloading, 445; Example 12-6. Effect
of Compressibility at High Pressure, 448; Air Com-
pressor Selection, 450; Energy flow, 451; Constant-
T system, 454; Polytropic System, 454; Constant-S
System, 455; Example 12-7. Use of Figure 12-35 Air
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Chart (©W. T. Rice), 455; Centrifugal Compres-
sors, 455; Mechanical Considerations, 455; Speci-
fications, 470; Performance Characteristics, 479;
Inlet Volume, 480; Centrifugal Compressor
Approximate Rating by the “N” Method, 491;
Compressor Calculations by the Mollier Diagram
Method, 493; Example 12-8. Use of Mollier Dia-
gram, 495; Example 12-9. Comparison of Poly-
tropic Head and Efficiency with Adiabatic Head
and Efficiency, 496; Example 12-10. Approximate
Compressor Selection, 500; Operating Character-
istics, 504; Example 12-11. Changing Characteris-
tics at Constant Speed, 509; Example 12-12.
Changing Characteristics at Variable Speed, 510;
Expansion Turbines, 512; Axial Compressor, 513;
Operating Characteristics, 513; Liquid Ring Com-
pressors, 516; Operating Characteristics, 517;
Applications, 518; Rotary Two-Impeller (Lobe)
Blowers and Vacuum Pumps, 518; Construction
Materials, 519; Performance, 519; Rotary Axial
Screw Blower and Vacuum Pumps, 522; Perfor-
mance, 523; Advantages, 524; Disadvantages, 524;

Rotary Sliding Vane Compressor, 526; Perfor-
mance, 528; Types of Fans, 531; Specifications,
535; Construction, 535; Fan Drivers, 542; Perfor-
mance, 544; Summary of Fan Selection and Rat-
ing, 544; Pressures, 547; Example 12-13. Fan
Selection, 547; Operational Characteristics and
Performance, 549; Example 12-14. Fan Selection
Velocities, 549; Example 12-15. Change Speed of
Existing Fan, 559; Example 12-16. Fan Law 1, 560;
Example 12-17. Change Pressure of Existing Fan,
Fan Law 2, 560; Example 12-18. Rating Conditions
on a Different Size Fan (Same Series) to Corre-
spond to Existing Fan, 560; Example 12-19. Chang-
ing Pressure at Constant Capacity, 560; Example
12-20. Effect of Change in Inlet Air Temperature,
560; Peripheral Velocity or Tip Speed, 561; Horse-
power, 561; Efficiency, 562; Example 12-21. Fan
Power and Efficiency, 562; Temperature Rise, 562;
Fan Noise, 562; Fan Systems, 563; System Compo-
nent Resistances, 564; Duct Resistance, 565; Sum-
mary of Fan System Calculations, 565; Parallel
Operation, 567; Fan Selection, 569; Multirating
Tables, 569; Example 12-22. Fan Selection for Hot
Air, 571; Example 12-23. Fan Selection Using a
Process Gas, 573; Blowers and Exhausters, 573;
Nomenclature, 573; Greek Symbols, 577; Sub-
scripts, 577; References, 577; Bibliography, 580
13 Reciprocating Compression
Surge Drums 581
Pulsation Dampener or Surge Drum, 581; Com-

mon Design Terminology, 582; Applications, 585;
Internal Details, 591; Design Method — Surge
Drums (Nonacoustic), 591; Single-Compression
Cylinder, 591; Parallel Multicylinder Arrangement
Using Common Surge Drum, 592; Pipe Sizes for
Surge Drum Systems2, 12, 593; Example 13-1.
Surge Drums and Piping for Double-Acting, Paral-
lel Cylinder, Compressor Installation, 593; Exam-
ple 13-2. Single Cylinder Compressor, Single
Acting, 596; Frequency of Pulsations, 596; Com-
pressor Suction and Discharge Drums, 597; Design
Method — Acoustic Low Pass Filters, 597; Exam-
ple 13-3. Sizing a Pulsation Dampener Using
Acoustic Method, 602; Design Method — Modi-
fied NACA Method for Design of Suction and Dis-
charge Drums, 608; Example 13-4. Sample
Calculation, 609; Pipe Resonance, 611; Mechani-
cal Considerations: Drums/Bottles and Piping,
612; Nomenclature, 613; Greek, 614; Subscripts,
614; References, 614; Bibliography, 614
14 Mechanical Drivers 615
Electric Motors, 615; Terminology, 615; Load
Characteristics, 616; Basic Motor Types: Synchro-
nous and Induction, 616; Selection of Synchro-
nous Motor Speeds, 619; Duty, 625; Types of
Electrical Current, 625; Characteristics, 627;
Energy Efficient (EE) Motor Designs, 628; NEMA
Design Classifications, 630; Classification Accord-
ing to Size, 630; Hazard Classifications: Fire and
Explosion, 631; Electrical Classification for Safety

in Plant Layout, 647; Motor Enclosures, 649;
Motor Torque, 651; Power Factor for Alternating
Current, 652; Motor Selection, 653; Speed
Changes, 654; Adjustable Speed Drives, 659,
Mechanical Drive Steam Turbines, 659; Standard
Size Turbines, 661; Applications, 662; Major Vari-
ables Affecting Turbine Selection and Operation,
662; Speed Range, 662; Efficiency Range, 662;
Motive Steam, 662; Example 14-3, 663; Selection,
663; Operation and Control, 666; Performance,
671; Specifications, 671; Steam Rates, 672; Single-
Stage Turbines, 673; Multistage Turbines, 680; Gas
and Gas-Diesel Engines, 680; Example 14-1: Full
Load Steam Rate, Single-Stage Turbine, 680;
Example 14-2: Single-Stage Turbine Partial Load
at Rated Speed, 680; Application, 681; Engine
Cylinder Indicator Cards, 681; Speed, 682; Tur-
bocharging and Supercharging, 683; Specifica-
tions, 683; Combustion Gas Turbine, 683;
Nomenclature, 686; References, 687; Bibliogra-
phy, 690
vii
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The techniques of process design continue to improve as
the science of chemical engineering develops new and bet-
ter interpretations of fundamentals. Accordingly, this sec-
ond edition presents additional, reliable design methods
based on proven techniques and supported by pertinent
data. Since the first edition, much progress has been made

in standardizing and improving the design techniques for
the hardware components that are used in designing
process equipment. This standardization has been incorpo-
rated in this latest edition, as much as practically possible.
The “heart” of proper process design is interpreting the
process requirements into properly arranged and sized
mechanical hardware expressed as (1) off-the-shelf mechan-
ical equipment (with appropriate electric drives and instru-
mentation for control); (2) custom-designed vessels,
controls, etc.; or (3) some combination of (1) and (2). The
unique process conditions must be attainable in, by, and
through the equipment. Therefore, it is essential that the
process designer carefully visualize physically and mathe-
matically just how the process will behave in the equipment
and through the control schemes proposed.
Although most of the chapters have been expanded to
include new material, some obsolete information has been
removed.
Chapter 10, “Heat Transfer,” has been updated and now
includes several important design techniques for difficult
condensing situations and for the application of ther-
mosiphon reboilers.
Chapter 11, “Refrigeration Systems,” has been improved
with additional data and new systems designs for light hydro-
carbon refrigeration.
ix
Chapter 12, “Compression Equipment,” has been gener-
ally updated.
Chapter 13, “Compression Surge Drums,” presents sev-
eral new techniques, as well as additional detailed examples.

Chapter 14, “Mechanical Drivers,” has been updated to
inlcude the latest code and standards of the National Elec-
trical Manufacturer’s Association and information on the
new energy efficient motors.
Also, the new appendix provides an array of basic refer-
ence and conversion data.
Although computers are now an increasingly valuable
tool for the process design engineer, it is beyond the scope
of these three volumes to incorporate the programming and
mathematical techniques required to convert the basic
process design methods presented into computer programs.
Many useful computer programs now exist for process
design, as well as optimization, and the process designer is
encouraged to develop his/her own or to become familiar
with available commercial programs through several of the
recognized firms specializing in design and simulation com-
puter software.
The many aspects of process design are essential to the
proper performance of the work of chemical engineers and
other engineers engaged in the process engineering design
details for chemical and petrochemical plants. Process
design has developed by necessity into a unique section of
the scope of work for the broad spectrum of chemical engi-
neering.
Foreword to the Second Edition
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This volume of Applied Process Design is intended to be a
chemical engineering process design manual of methods
and proven fundamentals with supplemental mechanical

and related data and charts (some in the expanded appen-
dix). It will assist the engineer in examining and analyzing a
problem and finding a design method and mechanical spec-
ifications to secure the proper mechanical hardware to
accomplish a particular process objective. An expanded
chapter on safety requirements for chemical plants and
equipment design and application stresses the applicable
codes, design methods, and the sources of important new
data.
This manual is not intended to be a handbook filled with
equations and various data with no explanation of applica-
tion. Rather, it is a guide for the engineer in applying chem-
ical processes to the properly detailed hardware
(equipment), because without properly sized and internally
detailed hardware, the process very likely will not accom-
plish its unique objective. This book does not develop or
derive theoretical equations; instead, it provides direct appli-
cation of sound theory to applied equations useful in the
immediate design effort. Most of the recommended equa-
tions have been used in actual plant equipment design and
are considered to be some of the most reasonable available
(excluding proprietary data and design methods), which
can be handled by both the inexperienced as well as the
experienced engineer. A conscious effort has been made to
offer guidelines of judgment, decisions, and selections, and
some of this will also be found in the illustrative problems.
My experience has shown that this approach at presentation
of design information serves well for troubleshooting plant
operation problems and equipment/systems performance
analysis. This book also can serve as a classroom text for

senior and graduate level chemical plant design courses at
the university level.
The text material assumes that the reader is an under-
graduate engineer with one or two years of engineering fun-
damentals or a graduate engineer with a sound knowledge
of the fundamentals of the profession. This book will pro-
vide the reader with design techniques to actually design as
well as mechanically detail and specify. It is the author’s phi-
losophy that the process engineer has not adequately per-
formed his or her function unless the results of a process
calculation for equipment are specified in terms of some-
thing that can be economically built or selected from the
special designs of manufacturers and can by visual or men-
tal techniques be mechanically interpreted to actually per-
xi
form the process function for which it was designed. Con-
siderable emphasis in this book is placed on the mechanical
Codes and some of the requirements that can be so impor-
tant in the specifications as well as the actual specific design
details. Many of the mechanical and metallurgical specifics
that are important to good design practice are not usually
found in standard mechanical engineering texts.
The chapters are developed by design function and not in
accordance with previously suggested standards for unit
operations. In fact, some of the chapters use the same prin-
ciples, but require different interpretations that take into
account the process and the function the equipment performs
in the process.
Because of the magnitude of the task of preparing the
material for this new edition in proper detail, it has been

necessary to omit several important topics that were covered
in the previous edition. Topics such as corrosion and met-
allurgy, cost estimating, and economics are now left to the
more specialized works of several fine authors. The topic of
static electricity, however, is treated in the chapter on
process safety, and the topic of mechanical drivers, which
includes electric motors, is covered in a separate chapter
because many specific items of process equipment require
some type of electrical or mechanical driver. Even though
some topics cannot be covered here, the author hopes that
the designer will find design techniques adaptable to 75 per-
cent to 85+ percent of required applications and problems.
The techniques of applied chemical plant process design
continue to improve as the science of chemical engineering
develops new and better interpretations of the fundamen-
tals for chemistry, physics, metallurgical, mechanical, and
polymer/plastic sciences. Accordingly, this third edition pre-
sents additional reliable design methods based on proven
techniques developed by individuals and groups considered
competent in their subjects and who are supported by per-
tinent data. Since the first and second editions, much
progress has been made in standardizing (which implies a
certain amount of improvement) the hardware components
that are used in designing process equipment. Much of the
important and basic standardization has been incorporated
in this latest edition. Every chapter has been expanded and
updated with new material.
All of the chapters have been carefully reviewed and older
(not necessarily obsolete) material removed and replaced by
newer design techniques. It is important to appreciate that

not all of the material has been replaced because much of
the so-called “older” material is still the best there is today,
Preface to the Third Edition
66131_Ludwig_FM 5/30/2001 4:04 PM Page xi
and still yields good designs. Additional charts and tables
have been included to aid in the design methods or explain-
ing the design techniques.
The author is indebted to the many industrial firms that
have so generously made available certain valuable design
data and information. Thus, credit is acknowledged at the
appropriate locations in the text, except for the few cases
where a specific request was made to omit this credit.
The author was encouraged to undertake this work by Dr.
James Villbrandt and the late Dr. W. A. Cunningham and Dr.
John J. McKetta. The latter two as well as the late Dr. K. A.
Kobe offered many suggestions to help establish the useful-
xii
ness of the material to the broadest group of engineers and
as a teaching text.
In addition, the author is deeply appreciative of the cour-
tesy of the Dow Chemical Co. for the use of certain non-
credited materials and their release for publication. In this
regard, particular thanks is given to the late N. D. Griswold
and Mr. J. E. Ross. The valuable contribution of associates in
checking material and making suggestions is gratefully
acknowledged to H. F. Hasenbeck, L. T. McBeth, E. R.
Ketchum, J. D. Hajek, W. J. Evers, and D. A. Gibson. The
courtesy of the Rexall Chemical Co. to encourage comple-
tion of the work is also gratefully appreciated.
Ernest E. Ludwig. P.E.

66131_Ludwig_FM 5/30/2001 4:04 PM Page xii
1
Chapter
10
Heat Transfer
Heat transfer is perhaps the most important, as well as the
most applied process, in chemical and petrochemical plants.
Economics of plant operation often are controlled by the
effectiveness of the use and recovery of heat or cold (refriger-
ation). The service functions of steam, power, refrigeration
supply, and the like are dictated by how these services or utili-
ties are used within the process to produce an efficient con-
version and recovery of heat.
Although many good references (5, 22, 36, 37, 40, 61, 70,
74, 82) are available, and the technical literature is well repre-
sented by important details of good heat transfer design prin-
ciples and good approaches to equipment design, an
unknown factor that enters into every design still remains. This
factor is the scale or fouling from the fluids being processed
and is wholly dependent on the fluids, their temperature and
velocity, and to a certain extent the nature of the heat transfer
tube surface and its chemical composition. Due to the
unknown nature of the assumptions, these fouling factors can
markedly affect the design of heat transfer equipment. Keep
this in mind as this chapter develops. Conventional practice is
presented here; however, Kern
71
has proposed new thermal
concepts that may offer new approaches.
Before presenting design details, we will review a sum-

mary of the usual equipment found in process plants.
The design of the heat transfer process and the associated
design of the appropriate hardware is now almost always
being performed by computer programs specifically devel-
oped for particular types of heat transfer. This text does not
attempt to develop computer programs, although a few
examples are illustrated for specific applications. The impor-
tant reason behind this approach is that unless the design
engineer working with the process has a “feel” for the
expected results from a computer program or can assess
whether the results calculated are proper, adequate, or “in
the right ball park,” a plant design may result in improperly
selected equipment sizing. Unless the user-designer has some
knowledge of what a specific computer program can accomplish, on
what specific heat transfer equations and concepts the program is
based, or which of these concepts have been incorporated into the pro-
gram, the user-designer can be “flying blind” regarding the results,
not knowing whether they are proper for the particular con-
ditions required. Therefore, one of the intended values of
this text is to provide the designer with a basis for manually
checking the expected equations, coefficients, etc., which
will enable the designer to accept the computer results. In
addition, the text provides a basis for completely designing
the process heat transfer equipment (except specialized
items such as fired heaters, steam boiler/generators, cryo-
genic equipment, and some other process requirements)
and sizing (for mechanical dimensions/details, but not for
pressure strength) the mechanical hardware that will accom-
plish this function.
Types of Heat Transfer Equipment Terminology

The process engineer needs to understand the terminol-
ogy of the heat transfer equipment manufacturers in order
to properly design, specify, evaluate bids, and check draw-
ings for this equipment.
The standards of the Tubular Exchanger Manufacturers
Association (TEMA)
107
is the only assembly of unfired
mechanical standards including selected design details and
Recommended Good Practice and is used by all reputable
exchanger manufacturers in the U.S. and many manufac-
turers in foreign countries who bid on supplying U.S. plant
equipment. These standards are developed, assembled, and
updated by a technical committee of association members.
The standards are updated and reissued every 10 years.
These standards do not designate or recommend thermal
design methods or practices for specific process applications
but do outline basic heat transfer fundamentals and list sug-
gested fouling factors for a wide variety of fluid or process
services.
The three classes of mechanical standards in TEMA are
Classes R, C, and B representing varying degrees of mechan-
ical details for the designated process plant applications’
severity. The code designations [TEMAϪ1988 Ed] for
mechanical design and fabrication are:
RCB
—
Includes all classes of construction/design and
are identical; shell diameter (inside) not exceeding 60 in.,
and maximum design pressure of 3,000 psi.

R
—
Designates severe requirements of petroleum and
other related processing applications.
66131_Ludwig_CH10A 5/30/2001 4:06 PM Page 1
2 Applied Process Design for Chemical and Petrochemical Plants
Figure 10-1A. Nomenclature for Heat Exchanger Components. Figures 10-1A
—
G used by permission: Standards of Tubular Exchanger Manu-
facturers Association, 7
th
Ed., Fig. N
—
1.2, © 1988. Tubular Exchanger Manufacturers Association, Inc.
Figure 10-1B. Floating head. (© 1988 by Tubular Exchanger Manufacturers Association, Inc.)
66131_Ludwig_CH10A 5/30/2001 4:06 PM Page 2
3Heat Transfer
Figure 10-1D. Floating head
—
outside packed. (© 1988 by Tubular Exchanger Manufacturers Association, Inc.)
Figure 10-1C. Fixed tubesheet. (© 1988 by Tubular Exchanger Manufacturers Association, Inc.)
C
—
Indicates generally moderate requirements of com-
mercial and general process applications.
B
—
Specifies design and fabrication for chemical
process service.
RGP

—
Recommended Good Practice, includes topics
outside the scope of the basic standards.
Note: The petroleum, petrochemical, chemical, and other
industrial plants must specify or select the design/fabrica-
tion code designation for their individual application as the
standards do not dictate the code designation to use. Many
chemical plants select the most severe designation of Class R
rather than Class B primarily because they prefer a more
rugged or husky piece of equipment.
In accordance with the TEMA Standards, the individual
vessels must comply with the American Society of Mechani-
cal Engineers (ASME) Boiler and Pressure Vessel Code, Sec-
tion VIII, Div. 1, plus process or petroleum plant location
state and area codes. The ASME Code Stamp is required by
the TEMA Standards.
Figures 10-1A
—
G and Table 10-1 from the Standards of
Tubular Exchanger Manufacturers Association
107
give the
nomenclature of the basic types of units. Note the nomen-
clature type designation code letters immediately below each
illustration. These codes are assembled from Table 10-1 and
Figures 10-1A
—
G.
Many exchangers can be designed without all parts;
specifically the performance design may not require (a) a

floating head and its associated parts, or (b) an impinge-
ment baffle but may require a longitudinal shell side baffle
(see Figures 10-1F and 10-1G). It is important to recognize
that the components in Figures 10-1B
—
K are associated with
the basic terminology regardless of type of unit. An applica-
tion and selection guide is shown in Table 10-2 and Figures
10-2 and 10-3.
66131_Ludwig_CH10A 5/30/2001 4:06 PM Page 3
4 Applied Process Design for Chemical and Petrochemical Plants
Figure 10-1E. Removable U-bundle. (© 1988 by Tubular Exchanger Manufacturers Association, Inc.)
Figure 10-1F. Kettle reboiler. (© 1988 by Tubular Exchanger Manufacturers Association, Inc.)
Figure 10-1G. Divided flow
—
packed tubesheet. (© 1988 by Tubular Exchanger Manufacturers Association, Inc.)
66131_Ludwig_CH10A 5/30/2001 4:06 PM Page 4
5Heat Transfer
Table 10-1
Standard TEMA Heat Exchanger Terminology/Nomenclature
*
1. Stationary Head—Channel 21. Floating Head Cover—External
2. Stationary Head—Bonnet 22. Floating Tubesheet Skirt
3. Stationary Head Flange—Channel or Bonnet 23. Packing Box
4. Channel Cover 24. Packing
5. Stationary Head Nozzle 25. Packing Gland
6. Stationary Tubesheet 26. Lantern Ring
7. Tubes 27. Tierods and Spacers
8. Shell 28. Transverse Baffles or Support Plates
9. Shell Cover 29. Impingement Plate

10. Shell Flange—Stationary Head End 30. Longitudinal Baffle
11. Shell Flange—Rear Head End 31. Pass Partition
12. Shell Nozzle 32. Vent Connection
13. Shell Cover Flange 33. Drain Connection
14. Expansion Joint 34. Instrument Connection
15. Floating Tubesheet 35. Support Saddle
16. Floating Head Cover 36. Lifting Lug
17. Floating Head Cover Flange 37. Support Bracket
18. Floating Head Backing Device 38. Weir
19. Split Shear Ring 39. Liquid Level Connection
20. Slip-on Backing Flange
*
Key to Figures 10-1B
—
G. See Figure 10-1A for Nomenclature Code.
Used by permission: Standards of Tubular Exchanger Manufacturers Association, 7
th
Ed., Table N-2, © 1988. Tubular
Exchanger Manufacturers Association, Inc. All rights reserved.
Figure 10-1H. Fixed tubesheet, single-tube pass vertical heater or
reboiler. (Used by permission: Engineers & Fabricators, Inc., Houston.)
66131_Ludwig_CH10A 5/30/2001 4:06 PM Page 5
6 Applied Process Design for Chemical and Petrochemical Plants
Figure 10-1I. Floating head, removable type. (Used by permission: Yuba Heat Transfer Division of Connell Limited Partnership.)
Figure 10-1J. Split-ring removable floating head, four-pass tube-side and two-pass shell-side. (Used by permission: Engineers & Fabricators,
Inc., Houston.)
Figure 10-1K. U-tube exchanger. (Used by permission: Yuba Heat Transfer Division of Connell Limited Partnership.)
66131_Ludwig_CH10A 5/30/2001 4:06 PM Page 6
7Heat Transfer
Table 10-2

Selection Guide Heat Exchanger Types
Approximate
Relative Cost
Type Figure in Carbon Steel
Designation No. Significant Feature Applications Best Suited Limitations Construction
Fixed 10
—
1C Both tubesheets Condensers; liquid-liquid; Temperature difference at 1.0
TubeSheet 10
—
1H fixed to shell. gas-gas; gas-liquid; cooling and extremes of about 200°F
heating, horizontal or vertical, due to differential
reboiling. expansion.
Floating Head 10
—
1B One tubesheet “floats” in High temperature differentials, Internal gaskets offer
or Tubesheet 10
—
1D shell or with shell, tube above about 200°F extremes; danger of leaking. 1.28
(removable and 10
—
1G bundle may or may not be dirty fluids requiring cleaning Corrosiveness of fluids on
nonremovable 10
—
1I removable from shell, but of inside as well as outside of shell-side floating parts.
bundles) 10
—
1J back cover can be removed shell, horizontal or vertical. Usually confined to
to expose tube ends. horizontal units.
U-Tube; 10

—
1E Only one tubesheet required. High temperature Bends must be carefully 0.9
—
1.1
U-Bundle 10
—
1K Tubes bent in U-shape. differentials, which might made, or mechanical damage
Bundle is removable. require provision for expansion and danger of rupture can
in fixed tube units. Clean result. Tube side velocities
service or easily cleaned can cause erosion of inside
conditions on both tube side of bends. Fluid should be
and shell side. Horizontal or free of suspended particles.
vertical.
Kettle 10
—
1F Tube bundle removable as Boiling fluid on shell side, as For horizontal installation. 1.2
—
1.4
U-type or floating head. refrigerant, or process fluid Physically large for other
Shell enlarged to allow being vaporized. Chilling or applications.
boiling and vapor cooling of tube-side fluid in
disengaging. refrigerant evaporation on
shell side.
Double Pipe 10
—
4A Each tube has own shell Relatively small transfer area Services suitable for finned 0.8
—
1.4
10
—

4B forming annular space for service, or in banks for larger tube. Piping-up a large
10
—
4C shell-side fluid. Usually use applications. Especially suited number often requires cost
10
—
4D externally finned tube. for high pressures in tube and space.
(greater than 400 psig).
Pipe Coil 10
—
5A Pipe coil for submersion in Condensing, or relatively low Transfer coefficient is low, 0.5
—
0.7
10
—
5B coil-box of water or sprayed heat loads on sensible transfer. requires relatively large
with water is simplest type space if heat load is high.
of exchanger.
Open Tube 10
—
5A Tubes require no shell, only Condensing, relatively low heat Transfer coefficient is low, 0.8
—
1.1
Sections (water 10
—
5B end headers, usually long, loads on sensible transfer. takes up less space than
cooled) water sprays over surface, pipe coil.
sheds scales on outside tubes
by expansion and contraction.
Can also be used in water box.

Open Tube 10
—
6 No shell required, only end Condensing, high-level heat Transfer coefficient is low, 0.8
—
1.8
Sections (air headers similar to water transfer. if natural convection
cooled); Plain or units. circulation, but is improved
Finned Tubes with forced air flow across
tubes.
Plate and 10
—
7A Composed of metal-formed Viscous fluids, corrosive fluids Not well suited for boiling 0.8
—
1.5
Frame 10
—
7B thin plates separated by slurries, high heat transfer. or condensing; limit
10
—
7C gaskets. Compact, easy to 350
—
500°F by gaskets. Used
clean. for liquid-liquid only; not
gas-gas.
Small-tube 10
—
8 Chemical resistance of tubes; Clean fluids, condensing, Low heat transfer
Teflon no tube fouling. cross-exchange. coefficient. 2.0
—
4.0

Spiral 10
—
9A Compact, concentric plates; Cross-flow, condensing, Process corrosion, 0.8
—
1.5
10
—
9B no bypassing, high heating. suspended materials.
10
—
9C turbulence.
10
—
9D
66131_Ludwig_CH10A 5/30/2001 4:06 PM Page 7
8 Applied Process Design for Chemical and Petrochemical Plants
Figure 10-2. Typical shell types.
Details of Exchange Equipment
Assembly and Arrangement
The process design of heat exchange equipment
depends to a certain extent upon the basic type of unit con-
sidered for the process and how it will be arranged together
with certain details of assembly as they pertain to that par-
ticular unit. It is important to recognize that certain basic
types of exchangers, as given in Table 10-2, are less expen-
sive than others and also that inherently these problems are
related to the fabrication of construction materials to resist
the fluids, cleaning, future reassignment to other services,
etc. The following presentation alerts the designer to the
various features that should be considered. Also see

Rubin.
281
1. Construction Codes
The American Society of Mechanical Engineers (ASME)
Unfired Pressure Vessel Code
119
is accepted by almost all states as
a requirement by law and by most industrial insurance
underwriters as a basic guide or requirement for fabrication
of pressure vessel equipment, which includes some compo-
nents of heat exchangers.
This code does not cover the rolling-in of tubes into
tubesheets.
For steam generation or any equipment having a direct
fire as the means of heating, the ASME Boiler Code
6
applies,
and many states and insurance companies require compli-
ance with this.
These classes are explained in the TEMA Standards and
in Rubin.
99, 100, 133
2. Thermal Rating Standards
The TEMA Code
107
does not recommend thermal
design or rating of heat exchangers. This is left to the rat-
ing or design engineer, because many unique details are
associated with individual applications. TEMA does offer
some common practice rating charts and tables, along

with some tabulations of selected petroleum and chemical
physical property data in the third (1952) and sixth (1978)
editions.
3. Exchanger Shell Types
The type of shell of an exchanger should often be estab-
lished before thermal rating of the unit takes place. The
shell is always a function of its relationship to the tubesheet
and the internal baffles. Figures 10-1, 10-2, and 10-3 sum-
marize the usual types of shells; however, remember that
other arrangements may satisfy a particular situation.
The heads attached to the shells may be welded or bolted
as shown in Figure 10-3. Many other arrangements may be
found in references 37, 38, and 61.
66131_Ludwig_CH10A 5/30/2001 4:06 PM Page 8
9Heat Transfer
Figure 10-4A(1). Double-pipe longitudinal Twin G-Finned exchanger. (Used by permission: Griscom-Russell Co./Ecolaire Corp., Easton, PA, Bul.
7600.)
Figure 10-3. Typical heads and closures.
66131_Ludwig_CH10A 5/30/2001 4:06 PM Page 9
10 Applied Process Design for Chemical and Petrochemical Plants
Figure 10-4A(2). Multitube hairpin fintube heat exchangers. The individual shell modules can be arranged into several configurations to suit the
process parallel and/or series flow arrangements. The shell size range is 3
—
16 in. (Used by permission: Brown Fintube Co., A Koch
®
Engineer-
ing Co., Bul. B
—
30
—

1.)
Figure 10-4A(3). Longitudinal fins resistance welded to tubes. The
welding of the fins integral to the parent tube ensures continuous
high heat transfer efficiency and the absence of any stress concen-
trations within the tube wall. (Used by permission: Brown Fintube Co.,
A Koch
®
Engineering Co., Bul. 80
—
1.)
4. Tubes
The two basic types of tubes are (a) plain or bare and (b)
finned
—
external or internal, see Figures 10-4A
—
E, 10-10,
and 10-11. The plain tube is used in the usual heat exchange
application. However, the advantages of the more common
externally finned tube are becoming better identified.
These tubes are performing exceptionally well in applica-
tions in which their best features can be used.
Plain tubes (either as solid wall or duplex) are available in
carbon steel, carbon alloy steels, stainless steels, copper,
brass and alloys, cupro-nickel, nickel, monel, tantalum, car-
bon, glass, and other special materials. Usually there is no
great problem in selecting an available tube material. How-
ever, when its assembly into the tubesheet along with the
resulting fabrication problems are considered, the selection
of the tube alone is only part of a coordinated design. Plain-

tube mechanical data and dimensions are given in Tables
10-3 and 10-4.
The duplex tube (Figure 10-11) is a tube within a tube,
snugly fitted by drawing the outer tube onto the inner or by
other mechanical procedures.
66131_Ludwig_CH10A 5/30/2001 4:06 PM Page 10
11Heat Transfer
Figure 10-4B. Cutaway view of finned double-pipe exchanger. (Used by permission: ALCO Products Co., Div. of NITRAM Energy, Inc.)
Figure 10-4C. High-pressure fixed-end closure and return-end closure. (Used by permission: ALCO Products Co., Div. of NITRAM Energy, Inc.)
66131_Ludwig_CH10A 5/30/2001 4:06 PM Page 11
12 Applied Process Design for Chemical and Petrochemical Plants
Figure 10-4D. Vertical longitudinal finned-tube tank heater, which is
used in multiple assemblies when required. (Used by permission:
Brown Fintube Co., A Koch
®
Engineering Co., Bul. 4
—
5.)
Figure 10-4E. Longitudinal finned-tube tank suction direct line heater.
(Used by permission: Brown Fintube Co., A Koch
®
Engineering Co.,
Bul. 4
—
5.)
Figure 10-4F(1). Single concentric corrugated tube in single corrugated shell. (Used by permission: APV Heat Transfer Technologies.)
Figure 10-4F(2). Multicorrugated tubes in single shell. (Used by permission: APV Heat Transfer Technologies.)
This tube is useful when the shell-side fluid is not com-
patible with the material needed for the tube-side fluid, or
vice versa. The thicknesses of the two different wall materials

do not have to be the same. As a general rule, 18 ga is about
as thin as either tube should be, although thinner gages are
available. In establishing the gage thickness for each com-
ponent of the tube, the corrosion rate of the material should
be about equal for the inside and outside, and the wall thick-
ness should still withstand the pressure and temperature
conditions after a reasonable service life.
More than 100 material combinations exist for these
tubes. A few materials suitable for the inside or outside of the
tube include copper, steel, cupro-nickel, aluminum, lead,
monel, nickel, stainless steel, alloy steels, various brasses, etc.
From these combinations most process conditions can be sat-
isfied. Combinations such as steel outside and admiralty or
cupro-nickel inside are used in ammonia condensers cooled
with water in the tubes. Tubes of steel outside and cupro-
nickel inside are used in many process condensers using sea
water. These tubes can be bent for U-bundles without loss of
effective heat transfer. However, care must be used, such as
by bending sand-filled or on a mandrel. The usual minimum
radius of the bend for copper-alloy
—
steel type duplex tube is
three times the O.D. of the tube. Sharper bends can be made
by localized heating; however, the tube should be specified at
the time of purchase for these conditions.
66131_Ludwig_CH10A 5/30/2001 4:06 PM Page 12
13Heat Transfer
Figure 10-5B. Elevation assembly
—
cast iron cooler sections.

Figure 10-4G. Twisted tubes with heat exchanger bundle arrangements. (Used by permission: Brown Fintube Co., A Koch
®
Engineering Co., Bul.
B
—
100
—
2.)
Figure 10-5A. Cast iron sections; open coil cooler-coil and distribu-
tion pan.
66131_Ludwig_CH10A 5/30/2001 4:07 PM Page 13