This book's purpose is to show how to apply mechanical engineering concepts to process system design. Process systems are common to a wide variety of industries including petrochemical processing, food and pharmaceutical manufacturing, power generation (including cogeneration), ship building, and even the aerospace industry. The book is based on years of proven, successful practice, and almost all of the examples described are from process systems now in operation.
While practicality is probably its key asset, this first volume contains a unique collection ofvaluable information, such as velocity head data; comparison ofthe flexibility and stiffness methods of pipe stress analyses; analysis of heat transfer through pipe supports and vessel skirts; a comprehensive method on the design of horizontal vessel saddles as well as a method to determine when wear plates are required; detailed static and dynamic methods of tower design considering wind gusts, vortex-induced vibration and seismic analysis of towers; and a comparative synopsis of the various national wind cooes.
Topics include.d in the text are considered to be those typically encountered in engineering practice. Therefore, because most mechanical systems involve single phase flow, two-phase flow is not covered. Because of its ubiquitous coverage in the literature, flange design is also excluded in this presentation. Since all of the major pressure vessel codes thoroughly discuss and illustrate the phenomenon of external pressure, this subject is only mentioned briefly.
This book is not intended to be a substitute or a replacement of any accepted code or standard. The reader is strongly encouraged to consult and be knowledgeable of any accepted standard or code that may govern. It is felt that this book is a valuable supplement to any standard or code used.
The book is slanted toward the practices of the ASME vessel and piping codes. In one area of vessel design the British Standard is favored because it nrovides excellent technical information on Zick rings. The book is written to be useful regardless of which code or standard is used.
The intent is not to be heavily prejudiced toward any standard, but to discuss the issue-engineering. If one feels that a certain standard or code should be mentioned, please keep in mind that there are others who may be using different standards and it is impossible to discuss all of them.
The reader's academic level is assumed to be a bachelor of science degree in mechanical engineering, but engineers with bachelor of science degrees in civil, chemical, electrical, or other engineering disciplines should have little difficulty with the book, provided, of course, that they have received adequate academic training or experience.
Junior or senior undergraduate engineering students should find the book a useful introduction to the application of mechanical engineering to process systems. Professors should find the book a helpful reference (and a source for potential exam problems), as well as a practical textbook for junior-, senior-, or graduate level courses in the mechanical, civil, or chemical engineering fields. The book can also be used to supplement an introductory level textbook.
The French philosopher Voltaire once said, "Common sense is not very common," and unfortunately, this is sometimes the case in engineering. Common sense is often the by-product of experience, and while both are essential to sound engineering practice, neither can be learned from books alone. It is one ofthis book's eoats to unite these three elements of "book learning," common sense, and experience to give the novice a better grasp of engineering principles and procedures, and serve as a
practical design reference for the veteran engineer.
Finally, I wish to thank Dr. John J. McKetta, professor of chemical engineering at the University of Texas at Austin, who had many helpful comments, suggestions, and words of encouragement. I also wish to thank other engineering faculty members at the University of Texas at Austin for their comments. I must exDress thanks to Larry D. Briggs for reviewing some calculations in Chapter 4; and last, but certainly not least, I wish to express gratitude to William J. Lowe and Timothy W. Calk
of Gulf Publishing Company, whose hard work and patience made this book possible.
Table of Contents:
Chapter 1
Piping Fluid Mechanics ........... 1
Basic Equations, I
Non-Newtonian Fluids, 5
Velocity Heads, 8
Pipe Flow Geometries, 22
Comoressible Flow. 25
Piping Fluid Mechanics Problem Formulation, 25
Example 1-1: Friction Pressure Drop for a Hydrocarbon Gas-Steam Mixture in a Pipe, 27
Example 1-2: Frictional Ptessure Drop for a Hot Oil System of a Process Thnk, 33
Example 1-3: Friction Pressure Drop for a Waste Heat Recovery System, 42
Example 1-4: Pressure Drop in Relief Valve Piping System, 43
Notation, 45
References, 45
Chapter 2
The Engineering Mechanics of Piping .,...47
Piping Criteria, 47
Primary and Secondary Stresses, 49
Allowable stress Range for Secondary Stresses.
Flexibility and Stiffness of Piping Systems, 52
Stiffness Method Advantages. Flexibility
Method Advantages.
Stiffness Method and Large Piping, 58
Flexibility Method of Piping Mechanics. Pipe
Loops.
PiD- e Restraints and Anchors. 68
Pipe Lug Supports. Spfing Supports. Expansion Joints. Pre-stressed Piping.
Fluid Forces Exerted on Piping Systems, 81
Extraneous Piping Loads, 83
Example 2-l: Applying the Stiffness Method to a Modular Skid-Mounted Gas Liquefaction Facility,88
Example 2-2: Applying the Flexibility Method to a Steam Turbine Exhaust Line, 95
Example 2-3: Flexibility Analysis for Hot Oil Piping,96
Example 2-42 Lug Design, 98
Example 2-5: Relief Valve Piping System, 99
Example 2-61 Wind-Induced Vibrations of Piping, 100
Notation, 101
References, 101
Chapter 3
Heat Transfer in Piping and Equipment ... 103
Jacketed Pipe versus Traced Pipe, 103
Tracing Piping Systems, 106
Traced Piping without Heat Tmnsfer Cement.
Traced Piping with Heat Transfer Cement.
Condensate Return. Jacketed Pipe. Vessel and
Equipment Traced Systems.
Heat Transfer in Residual Systems, 132
Heat Transfer through Cylindrical Shells. Residual Heat Transfer through Pipe Shoes.
Example 3-1: Steam Tracing Design, 136
Example 3-2: Hot Oil Tracing Design, 137
Example 3-3: Jacketed Pipe Design, 139
Example 3-4: Thermal Evaluation of a Process Thnk, 140
Example 3-5: Thermal Design of a Process Tank, 142
Internal Baffle Plates Film Coefficient. Film
Coefficient External to Baffles-Forced
Convection. Heat Duty of Internal Vessel
Plates. Outside Heat Transfer Jacket Plates.
Heat Duty of Jacket Plates Clamped to Bottom
Vessel Head. Total Heat Duty of Tank.
Example 3-6: Transient and Static Heat Transfer Design, 148
Static Heat Transfer Analysis. Total Heat
Removal. Water Required for Cooling.
Transient Hear Transfer Analysis.
Example 3-7: Heat Transfer through Vessel Skirts, 152
Example 3-E: Residual Heat Transfer, 154
Example 3-9: Heat Transfer through Pipe Shoe, 156
Notation, 156
References, 157
Chapter 4
The Engineering Mechanics of Pressure
Vessels ... . ..... 159
Designing for Internal Pressure, 159
Designing for External Pressure, 160
Design of Horizontal Pressure Vessels, 166
Longitudinal Bending Stresses. Location of Saddle Supports. Wear Plate Design. Zick
Stiffening Rings.
Steel Saddle Plate Design, 174
Saddle Bearing Plate Thickness, 180
Design of Self-Supported Vertical Vessels, 180
Minimum Shell Thickness Reouired for Combined Loads, 181
Support Skirt Design, 183
Anchor Bolts, 184
Base Plate Thickness Design, 186
Compression Ring and Gusset Plate Design, 189
Anchor Bolt Torque, 189
Whd Aralysis of Towers, 190
Wind Design Speeds. Wind-Induced Moments.
Wind-Induced Deflections of Towers. l ind-Induced Vibrations on Tall Towers.
Ovaling. Criteda for Vibration Analysis.
Seismic Design of Tall Towers, 209
Vertical Distribution of Shear Forces.
Tower Shell Discontinuities and Conical Sections, 1t i
Exanple 4-l: Wear Plate Requirement Analysis, 215
Example 12: Mechanical Design of Process Column. 215
Section moments of Inertial tower Section
Stress Calcularions. Skirt and Base Plate
Design- Section Centroids. Vortex-Induced
vibrarion. Equivalent Diameter Approach
versus - ANSI A58.1- 1982.
Example 4-3: Seismic Analysis of a Vertical Tower, 237
Example 44: Vibration Analysis for Tower with Large Vortex-Induced Displacements, 241
Moments of Inertia. Wind Deflections.
Example 4-5: Saddle Plate Analysis of a Horizontal Vessel, 249
Saddle Plate Buckling Analysis. Horizontal Reaction Force on Saddle.
Notation,252
References,254
