Contents
Cover
Half Title page
Title page
Copyright page
Dedication
Preface
Part I: Introduction
Chapter 1: Basic Calculations
Introduction
Units and Dimensions
Conversion of Units
The Gravitational Constant, gc
Significant Figures and Scientific Notation
References
Chapter 2: Process Variables
Introduction
Temperature
Pressure
Moles and Molecular Weights
Mass and Volume
Viscosity
Heat Capacity
Thermal Conductivity
Reynolds Number
pH
Vapor Pressure
Property Estimation
References
Chapter 3: Gas Laws
Introduction
Boyle’s and Charles’ Laws
The Ideal Gas Law
Standard Conditions
Partial Pressure and Partial Volume
Critical and Reduced Properties
Non-Ideal Gas Behavior
Non-Ideal Mixtures
References
Chapter 4: Conservation Laws
Introduction
The Conservation Laws
The Conservation Law for Momentum
The Conservation Law for Mass
The Conservation Law for Energy
References
Chapter 5: Stoichiometry
Introduction
Combustion of Methane
Excess and Limiting Reactant(s)
Combustion of Ethane
Combustion of Chlorobenzene
References
Chapter 6: The Second Law of Thermodynamics
Introduction
Qualitative Review of the Second Law
Quantitative Review of the Second Law
Ideal Work and Lost Work
The Heat Exchanger Dilemma
Chemical Plant and Process Applications
The Third Law of Thermodynamics
References
Part II: Enthalpy Effects
Chapter 7: Sensible Enthalpy Effects
Introduction
The Gibbs Phase Rule (GPR)
Enthalpy Values
Heat Capacity Values
Predictive Methods for Heat Capacity
References
Chapter 8: Latent Enthalpy Effects
Introduction
The Clausius–Clapeyron (C–C) Equation
Predictive Methods: Normal Boiling Point
Predictive Methods: Other Temperatures
Industrial Applications
References
Chapter 9: Enthalpy of Mixing Effects
Introduction
Enthalpy-Concentration Diagrams
H2SO4–H2O Diagram
NaOH–H2O Diagram
Enthalpy of Mixing at Infinite Dilution
Evaporator Design
References
Chapter 10: Chemical Reaction Enthalpy Effects
Introduction
Standard Enthalpy of Formation
Standard Enthalpy of Reaction
Effect of Temperature on Enthalpy of Reaction
Gross and Net Heating Values
References
Part III: Equilibrium Thermodynamics
Chapter 11: Phase Equilibrium Principles
Introduction
Psychometric Chart
Raoult’s Law
Henry’s Law
Raoult’s Law vs Henry’s Law
Vapor–Solid Equilibrium
Liquid–Solid Equilibrium
References
Chapter 12: Vapor–Liquid Equilibrium Calculations
Introduction
The DePriester Charts
Raoult’s Law Diagrams
Vapor–Liquid Equilibrium in Nonideal Solutions
NRTL Diagrams
Wilson Diagrams
Relative Volatility
References
Chapter 13: Chemical Reaction Equilibrium Principles
Introduction
Standard Free Energy of Formation, ΔGfo
Standard Free Energy of Reaction, ΔG0
The Chemical Reaction Equilibrium Constant, K
Effect of Temperature on ΔG0 and K: Simplified Approach
Effect of Temperature on ΔG0 and K: α, β, and γ Data
Effect of Temperature on ΔG0 and K: a, b, and c Data
Procedures to Determine K
References
Chapter 14: Chemical Reaction Equilibrium Applications
Introduction
Rate vs Equilibrium Considerations
Extent of Reaction
The Reaction Coordinate
Gas Phase Reactions
Equilibrium Conversion Calculations: Simplified Approach
Equilibrium Conversion Calculations: Rigorous Approach
Other Reactions
References
Part IV: Other Topics
Chapter 15: Economic Considerations
Introduction
Capital Costs
Operating Costs
Project Evaluation
Perturbation Studies in Optimization
References
Chapter 16: Open-Ended Problems
Introduction
Developing Students’ Power of Critical Thinking
Creativity
Brainstorming
Inquiring Minds
References
Chapter 17: Other ABET Topics
Introduction
Environmental Management
Health, Safety, and Accident Management
Numerical Methods
Ethics
References
Chapter 18: Fuel Options
Introduction
Fuel Properties
Natural Gas
Liquid Fuels
Coal
Fuel Selection
Stoichiometric Calculations
References
Chapter 19: Exergy: The Concept of “Quality Energy”
Introduction
The Quality of Heat vs Work
Exergy
Quantitative Exergy Analysis
Environmental Impact
Exergy Efficiency
References
Appendix
I. Steam Tables
II. SI Units
III. Conversion Constants
IV. Selected Common Abbreviations
References
Index
Thermodynamics for the Practicing Engineer
Copyright © 2009 by John Wiley & Sons, Inc. All rights reserved
Published by John Wiley & Sons, Inc., Hoboken, New Jersey
Published simultaneously in Canada
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Library of Congress Cataloging-in-Publication Data:
Theodore, Louis.
Thermodynamics for the practicing engineer / Louis Theodore.
p. cm.
Includes bibliographical references and index.
ISBN 978-0-470-44468-9 (cloth)
1. Thermodynamics. 2. Energy conversion. I. Title.
TJ265.T455 2009
621.402′1—dc22
2009016146
Thermodynamics for the Practicing Engineer
A. Edward Newton [1863–1940]
I wish that some one would give a course in how to live. It can’t be taught in the colleges: that’s perfectly obvious, for college professors don’t know any better than the rest of us.
—This Book-Collecting Game
Louis Theodore
Francesco Ricci
Timothy Van Vliet
Agnes Repplier [1858–1950]
That little band of authors who, unknown to the wide careless world, remain from generation to generation the friends of a few fortunate readers.
—Preface to James Howell
André Gide [1869–1951]
A unanimous chorus of praise is not an assurance of survival; authors who please everyone at once are quickly exhausted. I would prefer to think that a hundred years hence people will say we did not properly understand him.
—Pretexts
To my family and friends for their love and support, and to the Manhattan College Chemical Engineering Department for its commitment to greatness—without either of which, my dreams could never be realized (FR)
To George Scott, my high school technology teacher, for introducing me to this wonderful profession (TVV)
To Cecil K. Walkins, a friend who has contributed mightily to basketball and the youth of America (LT)
Plato [427–347 b.c.]
The beginning is the most important part of the work.
—The Republic, Book II
Preface
Sir Walter Scott [1771–1832]
Good wine needs neither bush nor preface to make it welcome.
—Peveril of the Peak
This project was a rather unique undertaking. Rather than prepare a textbook on thermodynamics in the usual and traditional format, the authors considered writing a book that highlighted applications rather then theory. The book would hopefully serve as a training tool for those individuals in academia and industry involved directly, or indirectly, with this topic. Despite the significant reduction in theoretical matter, it addresses both technical and pragmatic problems in this field. While this book can be viewed as a text in thermodynamics, it also stands alone as a self-teaching aid.
The book is divided into four parts:
I. Introduction
II. Enthalpy Effects
III. Equilibrium Thermodynamics
IV. Other Topics
The first part of the book serves as an introduction to the subject of thermodynamics and reviews such topics as units and dimensions, the conservation laws, gas laws, and the second law of thermodynamics. The second part of the book is concerned with enthalpy effects and reviews such topics as sensible, latent, mixing, and chemical enthalpy effects. The third part of the book examines equilibrium thermodynamics. Topics here include both phase and chemical reaction equilibrium. The fourth section of the book addresses the general all purpose title of other topics. Subjects reviewed here include economics, open-ended problems, environmental concerns, health and safety management, numerical methods, ethics, and exergy analysis.
The authors cannot claim sole authorship to all the problems and material in this book. The present text has evolved from a host of sources, including: notes, homework problems and exam problems prepared by L. Theodore for a required one-semester, three-credit “Chemical Engineering Thermodynamics” undergraduate course offered at Manhattan College; Introduction to Hazardous Waste Incineration, 2nd Edition, J. Santoleri, J. Reynolds, and L. Theodore, John Wiley & Sons; Chemical Reaction Kinetics, L. Theodore, a Theodore Tutorial; and, Introduction to Chemical Engineering Thermodynamics, 3rd Edition, J.M. Smith and H.C. Van Ness, McGraw-Hill. Although the bulk of the problems are original and/or taken from the sources that the authors have been directly involved with, every effort has been made to acknowledge material drawn from other sources.
The policy of most technical societies and publications is to use SI (metric) units or to list both the common British engineering unit and its SI equivalent. However, British units are primarily used in this book for the convenience of the majority of the reading audience. Readers who are more familiar and at ease with SI units are advised to refer to the Appendix of this book.
It is hoped that this writing will place in the hands of academic and industrial individuals a book covering the principles and applications of thermodynamics in a thorough and clear manner. Upon completion of the text, the reader should have acquired not only a working knowledge of the principles of thermodynamics but also experience in their application; and, the reader should find himself/herself approaching advanced texts, engineering literature, and industrial applications (even unique ones) with more confidence.
Sincere thanks are extended to Shannon O’Brien at Manhattan College for her invaluable help in solving some of the problems in the text, preparing part of the initial draft of the solutions manual, and proofing the manuscript. Special thanks are due Eric Huang and Pat Abulencia for their technical assistance in preparing parts of the manuscript.
L. THEODORE
F. RICCI
T. VAN VLIET
February 2009
Part I
Introduction
Nicolò Machiavelli [1469–1527]
There is nothing more difficult to take in hand, more perilous to conduct, or more uncertain in its success, than to take the lead in the introduction of a new order of things.
—The Prince. Chap. 6
Part I serves as the introductory section to this book. It reviews engineering and science fundamentals that are an integral part of the field of thermodynamics. It consists of six chapters, as noted below:
1 Basic Calculations
2 Process Variables
3 Gas Laws
4 Conservation Laws
5 Stoichiometry
6 The Second Law of Thermodynamics
Those individuals with a strong background in the above area(s) may choose to bypass this Part.
Chapter 1
Basic Calculations
Johann Wolfgang Von Goethe [1749–1832]
The sum which two married people owe to one another defies calculation. It is an infinite debt, which can only be discharged through all eternity.
—Elective Affinities [1808]. Book I, Chap. 9
INTRODUCTION
This first chapter provides a review of basic calculations and the fundamentals of measurement. Four topics receive treatment:
1 Units and Dimensions
2 Conversion of Units
3 The Gravitational Constant, gc
4 Significant Figures and Scientific Notation
The reader is directed to the literature in the reference section of this chapter if additional information on these four topics is deemed necessary.(1–3)
UNITS AND DIMENSIONS
The units used in this text are consistent with those adopted by the engineering profession in the United States. For engineering work, SI (Système International) and English units are most often employed; in the United States, the English engineering units are generally used, although efforts are still underway to obtain universal adoption of SI units for all engineering and science applications. The SI units have the advantage of being based on the decimal system, which allows for more convenient conversion of units within the system.
There are other systems of units. Some of the more common of these are shown in Table 1.1; however, English engineering units are primarily used in this text. Tables 1.2 and 1.3 present units for both the English and SI systems, respectively.
Table 1.1 Common Systems of Units
Table 1.2 English Engineering Units
Physical quantity |
Name of unit |
Symbol for unit |
Length |
foot |
ft |
Time |
second |
s |
Mass |
pound (mass) |
lb |
Temperature |
degree Rankine |
°R |
Temperature (alternative) |
degree Fahrenheit |
°F |
Moles |
pound · mole |
lbmol |
Energy |
British thermal unit |
Btu |
Energy (alternative) |
horsepower · hour |
hp · h |
Force |
pound (force) |
lbf |
Acceleration |
foot per second square |
ft/s2 |
Velocity |
foot per second |
ft/s |
Volume |
cubic foot |
ft3 |
Area |
square foot |
ft2 |
Frequency |
cycles per second, hertz |
cycles/s, Hz |
Power |
horsepower, Btu per second |
hp, Btu/s |
Heat capacity |
British thermal unit per (pound mass · degree Rankine) |
Btu/lb · °R |
Density |
pound (mass) per cubic foot |
lb/ft3 |
Pressure |
pound (force) per square inch |
psi |
|
pound (force) per square foot |
psf |
|
atmospheres |
atm |
|
bar |
bar |
Table 1.3 SI Units
Physical unit |
Name of unit |
Symbol for unit |
Length |
meter |
m |
Mass |
kilogram, gram |
kg, g |
Time |
second |
s |
Temperature |
Kelvin |
K |
Temperature (alternative) |
Celsius |
°C |
Moles |
gram · mole |
gmol |
Energy |
Joule |
J, kg · m2/s2 |
Force |
Newton |
N, kg · m/s2, J/m |
Acceleration |
meters per square second |
m/s2 |
Pressure |
Pascal, Newton per square meter |
Pa, N/m2 |
Pressure (alternative) |
bar |
bar |
Velocity |
meters per second |
m/s |
Volume |
cubic meter, liters |
m3, L |
Area |
square meter |
m2 |
Frequency |
Hertz |
Hz, cycles/s |
Power |
Watt |
W, kg · m2 · s3, J/s |
Heat capacity |
Joule per kilogram · Kelvin |
J/kg · K |
Density |
kilogram per cubic meter |
kg/m3 |
Angular velocity |
radians per second |
rad/s |
Some of the more common prefixes for SI units are given in Table 1.4, and decimal equivalents are provided in Table 1.5. Conversion factors between SI and English units and additional details on the SI system are provided in the Appendix III.
Table 1.4 Prefixes for SI Units
Table 1.5 Decimal Equivalents
Inch in fractions |
Decimal equivalent |
Millimeter equivalent |
|
A. 4ths and 8ths |
|
1/8 |
0.125 |
3.175 |
1/4 |
0.250 |
6.350 |
3/8 |
0.375 |
9.525 |
1/2 |
0.500 |
12.700 |
5/8 |
0.625 |
15.875 |
3/4 |
0.750 |
19.050 |
7/8 |
0.875 |
22.225 |
|
B. 16ths |
|
1/16 |
0.0625 |
1.588 |
3/16 |
0.1875 |
4.763 |
5/16 |
0.3125 |
7.938 |
7/16 |
0.4375 |
11.113 |
9/16 |
0.5625 |
14.288 |
11/16 |
0.6875 |
17.463 |
13/16 |
0.8125 |
20.638 |
15/16 |
0.9375 |
23.813 |
|
C. 32nds |
|
1/32 |
0.03125 |
0.794 |
3/32 |
0.09375 |
2.381 |
5/32 |
0.15625 |
3.969 |
7/32 |
0.21875 |
5.556 |
9/32 |
0.28125 |
7.144 |
11/32 |
0.34375 |
8.731 |
13/32 |
0.40625 |
10.319 |
15/32 |
0.46875 |
11.906 |
17/32 |
0.53125 |
13.494 |
19/32 |
0.59375 |
15.081 |
21/32 |
0.65625 |
16.669 |
23/32 |
0.71875 |
18.256 |
25/32 |
0.78125 |
19.844 |
27/32 |
0.84375 |
21.431 |
29/32 |
0.90625 |
23.019 |
31/32 |
0.96875 |
24.606 |
Two units that appear in dated literature are the poundal and slug. By definition, one poundal force will give a one pound mass an acceleration of one ft/s2. Alternatively, one slug can be defined as the mass that will accelerate one ft/s2 when acted upon by a one pound force; thus, a slug is equal to 32.2 pounds mass.
CONVERSION OF UNITS
Converting a measurement from one unit to another can be conveniently accomplished by using unit conversion factors; these factors are obtained from simple equations that relate the two units numerically. For example, from
(1.1)
the following conversion factor can be obtained:
(1.2)
Since this factor is equal to unity, multiplying some quantity (e.g., 18 ft) by this factor cannot alter its value. Hence
(1.3)
Note that in Equation (1.3), the old units of feet on the left-hand side cancel out leaving only the desired units of inches.
Physical equations must be dimensionally consistent. For the equality to hold, each term in the equation must have the same dimensions. This condition can be and should be checked when solving engineering problems. Throughout the text, great care is exercised in maintaining the dimensional formulas of all terms and the dimensional homogeneity of each equation. Equations will generally be developed in terms of specific units rather than general dimensions (e.g., feet rather than length). This approach should help the reader to more easily attach physical significance to the equations presented in these chapters.
ILLUSTRATIVE EXAMPLE 1.1
Convert units of acceleration in cm/s2 to miles/yr2.
SOLUTION: The procedure outlined above is applied to the units of cm/s2:
Thus, 1.0 cm/s2 is equal to 6.18 × 109 miles/yr2.
THE GRAVITATIONAL CONSTANT, gc
The momentum of a system is defined as the product of the mass and velocity of the system:
(1.4)
One set of units for momentum are therefore lb · ft/s. The units of the time rate of change of momentum (hereafter referred to as rate of momentum) are simply the units of momentum divided by time, i.e.,
The above units can be converted to lbf if multiplied by an appropriate constant. As noted earlier, a conversion constant is a term that is used to obtain units in a more convenient form; all conversion constants have magnitude and units in the term, but can also be shown to be equal to 1.0 (unity) with no units.
A defining equation is
(1.5)
If this equation is divided by lbf, one obtains
(1.6)
This serves to define the conversion constant gc. If the rate of momentum is divided by gc as 32.2 lb · ft/lbf · s2—this operation being equivalent to dividing by 1.0—the following units result:
(1.7)
It can be concluded from the above dimensional analysis that a force is equivalent to a rate of momentum.
SIGNIFICANT FIGURES AND SCIENTIFIC NOTATION(3)
Significant figures provide an indication of the precision with which a quantity is measured or known. The last digit represents, in a qualitative sense, some degree of doubt. For example, a measurement of 8.32 inches implies that the actual quantity is somewhere between 8.315 and 8.325 inches. This applies to calculated and measured quantities; quantities that are known exactly (e.g., pure integers) have an infinite number of significant figures.
The significant digits of a number are the digits from the first nonzero digit on the left to either (a) the last digit (whether it is nonzero or zero) on the right if there is a decimal point, or (b) the last nonzero digit of the number if there is no decimal point. For example:
370 |
has 2 significant figures |
370. |
has 3 significant figures |
370.0 |
has 4 significant figures |
28,070 |
has 4 significant figures |
0.037 |
has 2 significant figures |
0.0370 |
has 3 significant figures |
0.02807 |
has 4 significant figures |
Whenever quantities are combined by multiplication and/or division, the number of significant figures in the result should equal the lowest number of significant figures of any of the quantities. In long calculations, the final result should be rounded off to the correct number of significant figures. When quantities are combined by addition and/or subtraction, the final result cannot be more precise than any of the quantities added or subtracted. Therefore, the position (relative to the decimal point) of the last significant digit in the number that has the lowest degree of precision is the position of the last permissible significant digit in the result. For example, the sum of 3702., 370, 0.037, 4, and 37. should be reported as 4110 (without a decimal). The least precise of the five numbers is 370, which has its last significant digit in the tens position. The answer should also have its last significant digit in the tens position.
Unfortunately, engineers and scientists rarely concern themselves with significant figures in their calculations. However, it is recommended that—at least for this chapter—the reader attempt to follow the calculational procedure set forth in this subsection.
In the process of performing engineering calculations, very large and very small numbers are often encountered. A convenient way to represent these numbers is to use scientific notation. Generally, a number represented in scientific notation is the product of a number (< 10 but > or = 1) and 10 raised to an integer power. For example,
A positive feature of using scientific notation is that only the significant figures need appear in the number.
REFERENCES
1. R. Perry and D. Green (editors), “Perry’s Chemical Engineers’ Handbook,” 8th edition, McGraw-Hill, New York, 2008.
2. J. REYNOLDS, J. JERIS, and L. THEODORE, “Handbook of Chemical and Environmental Engineering Calculations,” John Wiley & Sons, Hoboken, NJ, 2004.
3. J. SANTOLERI, J. REYNOLDS, and L. THEODORE, “Introduction to Hazardous Waste Incineration,” 2nd edition, John Wiley & Sons, Hoboken, NJ, 2000.
NOTE: Additional problems for each chapter are available for all readers at www. These problems may be used for additional review or homework purposes.