Contents

Cover

Title page

Copyright page

Dedication

Preface

Introduction

Part I: Introduction to the Principles of Unit Operations

Chapter 1: History of Chemical Engineering and Unit Operations
1. References
Chapter 2: Transport Phenomena versus the Unit Operations Approach
1. References
Chapter 3: The Conservation Laws and Stoichiometry
1. 3.1 Overview
2. 3.2 The Conservation Law
3. 3.3 Conservation of Mass, Energy, and Momentum
4. 3.4 Stoichiometry
5. 3.5 Limiting and Excess Reactants
6. References
Chapter 4: The Ideal Gas Law
1. 4.1 Overview
2. 4.2 Other Forms of the Ideal Gas Law
3. 4.3 Non-Ideal Gas Behavior
4. References
Chapter 5: Thermodynamics
1. 5.1 Overview
2. 5.2 The First Law of Thermodynamics
3. 5.3 Enthalpy Effects
4. 5.4 Second Law Calculations [2]
5. 5.5 Phase Equilibrium
6. 5.6 Chemical Reaction Equilibrium
7. References
Chapter 6: Chemical Kinetics
1. 6.1 Overview
2. 6.2 Chemical Kinetics Principles
3. 6.3 Batch Reactors (BRs)
4. 6.4 Continuously Stirred Tank Reactors (CSTRs)
5. 6.5 Plug Flow Reactors (PFRs)
6. 6.6 Catalytic Reactors
7. References
Chapter 7: Equilibrium versus Rate Considerations
1. 7.1 Overview
2. 7.2 Equilibrium
3. 7.3 Transfer Process Rates
4. 7.4 Chemical Reaction Process Rates
5. References
Chapter 8: Process and Plant Design
1. 8.1 Overview
2. 8.2 Preliminary Studies
3. 8.3 Process Schematics
4. 8.4 Material and Energy Balances
5. 8.5 Equipment Design
6. 8.6 Instrumentation and Controls
7. 8.7 Plant Location and Layout [adopted from 8]
8. 8.8 Plant Design [adopted from 9]
9. References

Part II: Fluid Flow

Chapter 9: Fluid Behavior
1. 9.1 Introduction
2. 9.2 Newtonian Fluids [2]
3. 9.3 Strain Rate, Shear Rate, and Velocity Profiles
4. 9.4 Non-Newtonian Fluids
5. References
Chapter 10: Basic Energy Conservation Laws
1. 10.1 Introduction
2. 10.2 Conservation of Energy
3. 10.3 Total Energy Balance Equation
4. 10.4 The Mechanical Energy Balance Equation
5. 10.5 The Bernoulli Equation
6. References
Chapter 11: Law of Hydrostatics
1. 11.1 Introduction
2. 11.2 Pressure Principles
3. 11.3 Buoyancy Effects: Archimedes’ Law
4. 11.4 Manometer Principles
5. References
Chapter 12: Flow Measurement
1. 12.1 Introduction
2. 12.2 Manometry and Pressure Measurement
3. 12.3 Pitot Tubes
4. 12.4 Venturi Meters
5. 12.5 Orifice Meters
6. 12.6 Flow Meter Selection
7. Reference
Chapter 13: Flow Classification
1. 13.1 Introduction
2. 13.2 The Reynolds Number
3. 13.3 Laminar Flow in Pipes
4. 13.4 Turbulent Flow in Pipes
5. 13.5 Flow in Open Channels
6. References
Chapter 14: Prime Movers
1. 14.1 Introduction
2. 14.2 Fans [1]
3. 14.3 Pumps
4. 14.4 Compressors
5. References
Chapter 15: Valves and Fittings
1. 15.1 Introduction
2. 15.2 Valves [2]
3. 15.3 Fittings
4. 15.4 Expansion and Contraction Effects
5. 15.5 Calculating Frictional Losses due to Valves and Fittings
6. References
Chapter 16: Air Pollution Control Equipment
1. 16.1 Introduction
2. 16.2 Gravity Settlers and Cyclones
3. 16.3 Electrostatic Precipitators
4. 16.4 Venturi Scrubbers
5. 16.5 Baghouses
6. 16.6 Factors in Particulate Control Equipment Selection
7. 16.7 Comparing Control Equipment Alternatives [4]
8. References
Chapter 17: Sedimentation, Centrifugation, and Flotation
1. 17.1 Introduction
2. 17.2 Sedimentation
3. 17.3 Centrifugation
4. 17.4 Flotation
5. References
Chapter 18: Porous Media and Packed Beds
1. 18.1 Introduction
2. 18.2 Definitions [1]
3. 18.3 Flow Regimes
4. 18.4 Applications of Porous Media and Packed Beds
5. 18.5 The Carmen-Kozeny Equation
6. References
Chapter 19: Filtration
1. 19.1 Introduction
2. 19.2 Filtration Equipment
3. 19.3 Describing Equations
4. 19.4 Compressible Cakes
5. 19.5 Filtration Unit Selection
6. References
Chapter 20: Fluidization
1. 20.1 Introduction
2. 20.2 Fixed Beds
3. 20.3 Permeability
4. 20.4 Minimum Fluidization Velocity
5. 20.5 Bed Height, Pressure Drop and Porosity
6. 20.6 Fluidization Modes
7. References
Chapter 21: Membrane Technology
1. 21.1 Overview
2. 21.2 Membrane Separation Principles
3. 21.3 Reverse Osmosis (RO)
4. 21.4 Ultrafiltration, Microfiltration, and Gas Permeation
5. 21.5 Pervaporation and Electrodialysis
6. References
Chapter 22: Compressible and Sonic Flow
1. 22.1 Introduction
2. 22.2 Compressible Flow
3. 22.3 Sonic Flow
4. 22.4 Pressure Drop Equations
5. References
Chapter 23: Two-Phase Flow
1. 23.1 Introduction
2. 23.2 Gas (G)-Liquid (L) Flow Principles: Generalized Approach
3. 23.3 Gas (Turbulent) Flow-Liquid (Turbulent) Flow, tt
4. 23.4 Gas (Turbulent) Flow-Liquid (Viscous) Flow, tv
5. 23.5 Gas (Viscous) Flow-Liquid (Viscous) Flow, vv
6. 23.6 Gas-Solid Flow
7. References
Chapter 24: Ventilation
1. 24.1 Introduction
2. 24.2 Indoor Air Quality
3. 24.3 Indoor Air/Ambient Air Comparison
4. 24.4 Industrial Ventilation Systems
5. 24.5 Describing Equations
6. References
Chapter 25: Mixing
1. 25.1 Introduction
2. 25.2 Mixing Impellers
3. 25.3 Baffling
4. 25.4 Fluid Regimes
5. 25.5 Power Curves
6. 25.6 Scale-up
7. 25.7 Design of Mixing Equipment
8. References
Chapter 26: Biomedical Engineering
1. 26.1 Introduction
2. 26.2 Definitions
3. 26.3 Blood
4. 26.4 Blood Vessels
5. 26.5 Heart
6. 26.6 Plasma/Cell Flow
7. References

Part III: Heat Transfer

Chapter 27: Steady-State Conduction
1. 27.1 Introduction
2. 27.2 Fourier’s Law
3. 27.3 Conductivity Resistances
4. References
Chapter 28: Unsteady-State Conduction
1. 28.1 Introduction
2. 28.2 Classification of Unsteady-State Heat Conduction Processes
3. 28.3 Microscopic Equations
4. References
Chapter 29: Forced Convection
1. 29.1 Introduction
2. 29.2 Convective Resistances
3. 29.3 Heat Transfer Coefficients: Qualitative and Quantitative Information
4. 29.4 Flow in a Circular Tube
5. 29.5 Convection Across Cylinders
6. References
Chapter 30: Free Convection
1. 30.1 Introduction
2. 30.2 Key Dimensionless Numbers
3. 30.3 Describing Equations
4. 30.4 Environmental Applications
5. References
Chapter 31: Radiation
1. 31.1 Introduction
2. 32.2 Energy and Intensity
3. 31.3 Radiant Exchange
4. 31.4 Kirschoff’s Law
5. 31.5 Emissivity Factors
6. 31.6 View Factors
7. References
Chapter 32: The Heat Transfer Equation
1. 32.1 Introduction
2. 32.2 Energy Relationships
3. 32.3 Heat Exchange Equipment Classification
4. 32.4 The Log Mean Temperature Difference (LMTD) Driving Force
5. 32.5 Temperature Profiles
6. 32.6 Overall Heat Transfer Coefficients
7. 32.7 The Classic Heat Transfer Equation
8. References
Chapter 33: Double Pipe Heat Exchangers
1. 33.1 Introduction
2. 33.2 Equipment Description
3. 33.3 Describing Equations
4. 33.4 Effectiveness Factor and Number of Transfer Units
5. 33.5 Wilson’s Method
6. References
Chapter 34: Shell and Tube Heat Exchangers
1. 34.1 Introduction
2. 34.2 Equipment Description
3. 34.3 Describing Equations
4. 34.4 The “F” Factor
5. 34.5 Effectiveness Factor and Number of Transfer Units
6. 34.6 Design Procedure
7. References
Chapter 35: Finned Heat Exchangers
1. 35.1 Introduction
2. 35.2 Fin Types
3. 35.3 Describing Equations
4. 35.4 Fin Effectiveness and Performance
5. 35.5 Fin Considerations
6. References
Chapter 36: Other Heat Transfer Equipment
1. 36.1 Introduction
2. 36.2 Evaporators
3. 36.3 Waste Heat Boilers
4. 36.4 Condensers [9, 10]
5. 36.5 Quenchers
6. References
Chapter 37: Insulation and Refractory
1. 37.1 Introduction
2. 37.2 Describing Equations
3. 37.3 Insulation
4. 37.4 Refractory
5. References
Chapter 38: Refrigeration and Cryogenics
1. 38.1 Introduction
2. 38.2 Background Material
3. 38.3 Equipment
4. 38.4 Materials of Construction
5. 38.5 Insulation and Heat Loss
6. 38.6 Storage and Transportation
7. 38.7 Health and Hazard Risks, and Safety
8. 38.8 Basic Principles and Applications
9. References
Chapter 39: Condensation and Boiling
1. 39.1 Introduction
2. 39.2 Condensation Fundamentals
3. 39.3 Condensation Principles
4. 39.4 Boiling Fundamentals
5. 39.5 Boiling Principles
6. References
Chapter 40: Operation, Maintenance, and Inspection (OM&I)
1. 40.1 Introduction
2. 40.2 Installation Procedures
3. 40.3 Operation
4. 40.4 Maintenance and Inspection
5. 40.5 Testing
6. 40.6 Improving Operation and Performance
7. References
Chapter 41: Design Principles
1. 41.1 Introduction
2. 41.2 General Design Procedures
3. 41.3 Other Design Considerations
4. 41.4 Process Schematics
5. 41.5 Purchasing a Heat Exchanger [7–8]
6. References

Part IV: Mass Transfer

Chapter 42: Equilibrium Principles
1. 42.1 Introduction
2. 42.2 Gibb’s Phase Rule
3. 42.3 Important Phase Considerations
4. References
Chapter 43: Phase Equilibrium Relationships
1. 43.1 Introduction
2. 43.2 Raoult’s Law
3. 43.3 Henry’s Law
4. 43.4 Raoult’s Law versus Henry’s Law [7]
5. 43.5 Vapor-Liquid Equilibrium in Non-Ideal Solutions [1]
6. 43.6 Vapor-Solid and Liquid-Solid Equilibrium
7. References
Chapter 44: Rate Principles
1. 44.1 Introduction
2. 44.2 Fick’s Law
3. 44.3 Early Rate Transfer Theories
4. 44.4 The Operating Line
5. References
Chapter 45: Mass Transfer Coefficients
1. 45.1 Introduction
2. 45.2 Individual Mass Transfer Coefficients
3. 45.3 Overall Mass Transfer Coefficients
4. 45.4 Experimental Mass Transfer Coefficients
5. References
Chapter 46: Classification of Mass Transfer Operations
1. 46.1 Introduction
2. 46.2 Contact of Immiscible Phases
3. 46.3 Miscible Phases Separated by a Membrane
4. 46.4 Direct Contact of Miscible Phases
5. 46.5 Mass Transfer Operations Selection
6. References
Chapter 47: Characteristics of Mass Transfer Operations
1. 47.1 Overview
2. 47.2 Unsteady-State versus Steady-State Operation
3. 47.3 Flow Pattern
4. 47.4 Stage Wise versus Continuous Operation
5. References
Chapter 48: Absorption and Stripping
1. 48.1 Introduction
2. 48.2 Description of Equipment
3. 48.4 Plate Columns
4. References
Chapter 49: Distillation
1. 49.1 Introduction
2. 49.2 Flash Distillation
3. 49.3 Batch Distillation
4. 49.4 Continuous Distillation with Reflux
5. References
Chapter 50: Adsorption
1. 50.1 Introduction
2. 50.2 Adsorption Classification
3. 50.3 Adsorption Equilibria
4. 50.4 Description of Equipment
5. 50.5 Regeneration
6. References
Chapter 51: Liquid-Liquid and Solid-Liquid Extraction
1. 51.1 Introduction
2. 51.2 Liquid-Liquid Extraction
3. 51.3 Design and Predictive Equations
4. 51.4 Solid-Liquid Extraction (Leaching) [2]
5. References
Chapter 52: Humidification
1. 52.1 Introduction
2. 52.2 Psychrometry
3. 52.3 The Psychrometric Chart
4. 52.4 The Humidification Process
5. 52.5 Equipment
6. 52.6 Describing Equations
7. References
Chapter 53: Drying
1. 53.1 Introduction
2. 53.2 Drying Principles
3. 53.3 Describing Equations
4. 53.4 Drying Equipment
5. References
Chapter 54: Absorber Design and Performance Equations
1. 54.1 Introduction
2. 54.2 Packed Columns [1,2]
3. 54.3 Plate Columns
4. 54.4 Stripping
5. 54.5 Packed versus Plate Tower Comparison
6. 54.6 Summary of Key Equations
7. References
Chapter 55: Distillation Design and Performance Equations
1. 55.1 Introduction
2. 55.2 Binary Distillation Design/The McCabe-Thiele Graphical Method
3. 55.3 Constructing a McCabe-Thiele Diagram [6]
4. 55.4 Packed Column Distillation
5. References
Chapter 56: Adsorber Design and Performance Equations
1. 56.1 Introduction
2. 56.2 Design and Performance Principles [1,2]
3. 56.3 Design Methodology
4. 56.4 Simplified Design Procedures
5. References
Chapter 57: Crystallization
1. 57.1 Introduction
2. 57.2 The Crystallization Process
3. 57.3 Equipment
4. 57.4 Describing Equations
5. 57.5 Design Considerations
6. References
Chapter 58: Other and Novel Separation Processes
1. 58.1 Introduction
2. 58.2 Freeze Crystallization
3. 58.3 Ion Exchange
4. 58.4 Liquid Ion Exchange
5. 58.5 Resin Adsorption
6. 58.6 Evaporation
7. 58.7 Foam Fractionation
8. 58.8 Dissociation Extraction
9. 58.9 Electrophoresis
10. 58.10 Vibratory Screens
11. References

Part V: Case Studies

Chapter 59: Drag Force Coefficient Correlation
1. References
Chapter 60: Predicting Pressure Drop with Pipe Failure for Flow through Parallel Pipes
1. Reference
Chapter 61: Developing an Improved Model to Describe the Cunningham Correction Factor Effect
1. References
Chapter 62: Including Entropy Analysis in Heat Exchange Design
1. References
Chapter 63: Predicting Inside Heat Transfer Coefficients in Double-Pipe Exchangers
1. References
Chapter 64: Converting View Factor Graphical Data to Equation Form
1. Reference
Chapter 65: Correcting a Faulty Absorber Design
1. References
Chapter 66: A Unique Liquid-Liquid Extraction Unit
1. References
Chapter 67: Effect of Plate Failure on Distillation Column Performance
1. Reference

Appendix A: Units

A.1 SI Multiples and Prefixes
A.2 Conversion Constants (SI)
A.3 Selected Common Abbreviations

Appendix B: Miscellaneous Tables

B.1 Common Engineering Conversion Factors
B.2 Dimensions and Weights of Standard Steel Pipes
B.3 Dimensions of Heat Exchanger Tubes

Appendix C: Steam Tables

Appendix D: Basic Calculations

References

Index

End User License Agreement

List of Illustrations

Introduction

Figure I.1 Unit operations versus unit processes.

Chapter 1

Figure 1.1 Chemical Engineering time line [4].

Chapter 2

Figure 2.1 Fluid flow through a cylinder tube.

Chapter 8

Figure 8.1 Typical process flow diagram symbols.
Figure 8.2 Simple process flow diagram for an activated sludge wastewater treatment plant.

Chapter 9

Figure 9.1 Fluid/two plate system.
Figure 9.2 Velocity profile.
Figure 9.3 Velocity profile in a pipe under laminar, turbulent, and random flow conditions.
Figure 9.4 Fluid shear diagrams for a variety of fluid types.

Chapter 10

Figure 10.1 Fluid flow in a process.

Chapter 12

Figure 12.1 Bourdon-tube pressure gauge.
Figure 12.2 Open manometer pressure gauge.
Figure 12.3 Common depth measurement method for liquids in tanks.
Figure 12.4 Pitot tube employed for velocity measurements in pipes.
Figure 12.5 Typical Venturi flow meter.
Figure 12.6 Typical orifice meter.
Figure 12.7 Discharge coefficients for drilled plate orifices. D₂ is the orifice diameter, and D₁ is the pipe diameter. The abscissa is the Reynolds number based on the orifice conditions.

Chapter 13

Figure 13.1 Velocity profiles in pipes under different flow regimes.
Figure 13.2 Fanning friction factor for pipe flow.

Chapter 14

Figure 14.1 System and fan characteristic curves.
Figure 14.2 Pump system schematic.

Chapter 15

Figure 15.1 Schematic of sudden expansion in a pipeline.
Figure 15.2 Schematic of sudden contraction in a pipeline.

Chapter 17

Figure 17.1 Settling column results for a Type II suspension showing equal removal efficiency lines. Numbers listed on the figure are percent solids removal values determined from solids measurements at specified depths in the column at specified times during the settling column test.
Figure 17.2 Rigid body rotation.

Chapter 18

Figure 18.1 Schematic of typical packed bed reactor.
Figure 18.2 Typical packed bed cross-section.

Chapter 19

Figure 19.1 Plate-and-frame schematics.
Figure 19.2 Flow of the slurry through the filter press.

Chapter 20

Figure 20.1 Types of particle-fluid contact in a fixed bed.
Figure 20.2 Expanded bed porosity.

Chapter 21

Figure 21.1 Three common membrane separation processes.
Figure 21.2 Desalination of seawater by RO.
Figure 21.3 Pre-osmosis equilibrium.
Figure 21.4 Osmosis of a solvent.
Figure 21.5 Osmotic pressure.
Figure 21.6 Reverse osmosis.

Chapter 24

Figure 24.1 Industrial ventilation system.

Chapter 26

Figure 26.1 Cardiovascular circulatory system.

Chapter 27

Figure 27.1 Heat flow through a solid wall.
Figure 27.2 Heat transfer through an insulated incinerator wall.
Figure 27.3 Log mean area figure.

Chapter 28

Figure 28.1 Transient rod temperature system.

Chapter 29

Figure 29.1 Convection temperature profile.
Figure 29.2 Flow past a flat plate.

Chapter 30

Figure 30.1 A fluid contained between two horizontal plates at different temperatures. (a) Unstable temperature gradient, (b) Stable temperature gradient.
Figure 30.2 Stack plume rise.

Chapter 31

Figure 31.1 View factor illustration.

Chapter 32

Figure 32.1 Energy balance of a differential element of a pipe.
Figure 32.2 Parallel flow heat transfer.
Figure 32.3 Counter flow heat transfer.

Chapter 33

Figure 33.1 Double pipe heat exchanger schematic. (a) Parallel (co-current) flow. (b) Countercurrent flow.
Figure 33.2 (a) Co-current and (b) countercurrent flow in a double pipe heat exchanger.

Chapter 34

Figure 34.1 One shell pass, 2 tube passes (1–2 unit) schematic.
Figure 34.2 Side view of tube layout in the shell and tube heat exchanger.

Chapter 35

Figure 35.1 Longitudinal fins.
Figure 35.2 Transverse or circumferential fins.
Figure 35.3 Efficiency of straight rectangular fins (a), triangular fins (b), and parabolic profile fins (c). (Adapted from [4]).
Figure 35.4 Efficiency of annular fins of rectangular profiles. (Adapted from [4]).

Chapter 36

Figure 36.1 Material and enthalpy balance for a single-effect evaporator.
Figure 36.2 Contact condensers: (a) spray; (b) jet; (c) barometric.

Chapter 37

Figure 37.1 Flow past a flat plate.
Figure 37.2 Flow past a flat insulated plate.

Chapter 38

Figure 38.1 Basic Components of a Refrigeration System.
Figure 38.2 Basic components of a steam power system.

Chapter 39

Figure 39.1 Boiling curve. (Adapted from [4]).

Chapter 41

Figure 41.1 Selected flow sheet symbols.

Chapter 42

Figure 42.1 Phase diagram for water.

Chapter 43

Figure 43.1 Graphical representation of the vapor pressure of an ideal binary solution, i.e., one that obeys Raoult’s law for the entire composition range.
Figure 43.2 Ammonia absorption system at T and P.
Figure 43.3 x-y equilibrium point.
Figure 43.4 x-y equilibrium diagram showing multiple equilibrium points.
Figure 43.5 Graphical representation of the differences between Raoult’s and Henry’s law; Component B represents the solute.
Figure 43.6 Adsorption isotherms for carbon tetrachloride on activated carbon.

Chapter 44

Figure 44.1 Diffusion process.
Figure 44.2 Schematic sketch of gas transfer mechanism.
Figure 44.3 Equilibrium-operating line plot, liquid/gas mole ratio = 2.
Figure 44.4 Equilibrium operating line plot, liquid/gas mole ratio = 0.5.

Chapter 45

Figure 45.1 Concentration (mole fraction) profile of Solute A diffusing from one phase to another.
Figure 45.2 Overall concentration differences for diffusion profile in Figure 45.1.

Chapter 47

Figure 47.1 Single stage concurrent contacting process.
Figure 47.2 Operating diagram: single-stage device.
Figure 47.3 Two-state contacting process. (a) Co-current operation. (b) Countercurrent operation.
Figure 47.4 Operating diagram: countercurrent contacting operation.
Figure 47.5 Two-stage crossflow contacting process.
Figure 47.6 Operating diagram: cross current contacting.

Chapter 47

Figure 48.1 Typical countercurrent packed column.
Figure 48.2 Typical bubble-cap plate column.

Chapter 49

Figure 49.1 Flash distillation system.
Figure 49.2 Batch distillation diagram.
Figure 49.3 Schematic of a trayed, continuous distillation column.
Figure 49.4 Qualitative examination of rectification trays.

Chapter 50

Figure 50.1 Concept of molecular screening in micropores (diameter range = 10 to 1,000 A).
Figure 50.2 Vapor-solid equilibrium isotherms of some hydrocarbons on silica gel.
Figure 50.3 Vapor-solid equilibrium isotherms of some hydrocarbons on activated carbon.
Figure 50.4 CO₂ vapor-solid equilibrium isotherms on molecular sieves.
Figure 50.5 Stationary-bed carbon system with auxiliaries for vapor collection and solvent separation from steam condensate.

Chapter 51

Figure 51.1 Multistage extractors.
Figure 51.2 Three-stage cross current extraction system.
Figure 51.3 Single-stage leaching unit.
Figure 51.4 Multistage cross-flow leaching unit.
Figure 51.5 Multistage countercurrent leaching unit.
Figure 51.6 Material balance-countercurrent process.

Chapter 52

Figure 52.1 Psychrometric chart for the air-water vapor system at a pressure of 1 atm.
Figure 52.2 Psychrometric chart for high temperatures. Barometric pressure of 29.92 in Hg.

Chapter 53

Figure 53.1 Typical drying process: moisture content versus time.
Figure 53.2 Typical drying process: drying rate versus moisture content.

Chapter 54

Figure 54.1 Mole balance; countercurrent flow absorption column.
Figure 54.2 Operating and equilibrium lines.
Figure 54.3 Generalized pressure drop correlation to estimate column diameter.
Figure 54.4 Stripping unit.
Figure 54.5 Minimum gas to liquid ratio.

Chapter 55

Figure 55.1 Material balances around a distillation column.
Figure 55.2 Action on a feed tray: saturated feed.
Figure 55.3 Examples of g-lines.
Figure 55.4 Typical McCabe-Thiele diagram.

Chapter 56

Figure 56.1 Theoretical adsorption wave front in a packed adsorber column.

Chapter 57

Figure 57.1 Generalized diagram of the crystallization process.
Figure 57.2 Line diagram of an evaporative crystallizer.

Chapter 59

Figure 59.1 Drag coefficient for spheres.

Chapter 62

Figure 62.1 Kauffman’s [3] heat exchanger network. Numbers in heat exchanger boxes have units of Btu/hr.

Chapter 65

Figure 65.1 Absorber system that fails to meet design performance.

Chapter 66

Figure 66.1 Multistage extractors.
Figure 66.2 A hybrid extraction process.

List of Tables

Chapter 1

Table 4.1 Values of R in various units.
Table 4.2 Common standard conditions.

Chapter 13

Table 13.1 Average roughness of commercial pipes.

Chapter 14

Table 14.1 Typical fan multi-rating table.

Chapter 15

Table 15.1 Resistance coefficients, K, for open valves, elbows, and tees.
Table 15.2 Increased frictional losses for partially open valves.
Table 15.3 Summary of minor loss calculation methods.

Chapter 16

Table 16.1 Advantages and disadvantages of cyclone collectors.
Table 16.2 Advantages and disadvantages of ESPs.
Table 16.3 Advantages and disadvantages of wet scrubbers.
Table 16.4 Advantages and disadvantages of fabric filter systems.

Chapter 18

Table 18.1 Measurement units for standard particle sizes.
Table 18.2 Tyler standard screen and U.S. Sieve Size scales for particle size distribution analysis.

Chapter 22

Table 22.1 Speed of sound in various liquids.
Table 22.2 Values of k.

Chapter 23

Table 23.1 ϕ_tt vs X_tt.
Table 23.2 X_tv versus ϕ_tv.
Table 23.3 X_w versus ϕ_vv.

Chapter 26

Table 26.1 Fluid flow analogies in biomedical engineering.
Table 26.2 The average radii and total numbers of conventional categories of vessels of the human circulatory system.

Chapter 27

Table 27.1 Thermal conductivities of three common insulating materials.
Table 27.2 Thermal conductivities for materials of different states.

Chapter 28

Table 28.1 Unsteady-state energy-transfer equation for stationary solids [4, 5].

Chapter 29

Table 29.1 Typical film coefficients.
Table 29.2 Film coefficients in pipes^a.

Chapter 30

Table 30.1 Coefficients for Equation 30.14.
Table 30.2 Free convection equation in air.

Chapter 31

Table 31.1 Characteristic wavelengths [3].

Chapter 32

Table 32.1 Fouling coefficients (english units).

Chapter 33

Table 33.1 Reynolds number values versus type of flow.
Table 33.2 Representative fouling factors.

Chapter 35

Table 35.1 Fin metal data.
Table 35.2 Fin data.

Chapter 36

Table 36.1 Heat exchanger equipment.

Chapter 42

Table 42.1 Mass transfer scenarios.

Chapter 43

Table 43.1 Approximate Clapeyron equation coefficients*.
Table 43.2 Antoine equation coefficients*.

Chapter 44

Table 44.1 Diffusion coefficients.
Table 44.2 Liquid diffusivities at atmospheric pressure.

Chapter 45

Table 45.1 Controlling films for various systems.

Chapter 48

Table 48.1 Four Typical packings and applications.

Chapter 55

Table 55.1 Values of q and f for the five general feed conditions.
Table 55.2 Values of q-line slope and intercept for the five general feed conditions.
Table 55.3 Reflux ratio optimization multipliers.
Table 55.4 Recommended tray spacing.*

Chapter 56

Table 56.1 Adsorbent heat capacity values (ambient conditions Btu/ft³-°F).

Chapter 62

Table 62.1 Heated streams.
Table 62.2 Cooled streams.

Appendix C

Table C.1 Saturated Steam*
Table C.2 Superheated Steam.

Appendix D

Table D.1 Common systems of units.
Table D.2 English engineering units.
Table D.3 SI Units.

Preface

Unit operations are several of the basic tenets of not only chemical engineering but also several other engineering disciplines, and contains many practical concepts that are utilized in countless industrial applications. One engineering curriculum that has embraced the unit operations approach is environmental engineering, and interestingly, a comprehensive “overview text” in the subject area is not presently available in the literature. Therefore, the authors considered writing a practical introductory text involving unit operations for environmental engineers. The text will hopefully serve as a training tool for those individuals pursuing degrees that include courses on unit operations. Although the literature is inundated with texts in this area emphasizing theory and theoretical derivations, the goal of this text is to present the subject from a strictly pragmatic introductory point-of-view, particularly for those individuals involved with environmental engineering.

As noted in the opening paragraph and in the title of this book - Unit Operations in Environmental Engineering - this work has been written primarily for environmental engineering students. But, who are environmental engineers and what is the environmental engineering profession? The answer, to some degree, depends on who one talks to since this profession has undergone dramatic changes over the last half century. The term environmental engineering came into existence in the mid-1960s when it displaced the perhaps politically incorrect term, sanitary engineering.

The reader should keep in mind that during the late 1900s, it was no secret that industry preferred to hire chemical engineers to address real-world environmental engineering problems. This was no doubt brought about because of the chemical engineer’s understanding, and the environmental engineer’s lack of knowledge, of unit operations, particularly those related to mass transfer operations.

Interestingly, the early sanitary engineering curriculum was almost exclusively based on primarily “water” topics, e.g., sewage, water supply and usage, sanitation, etc. The expansion of environmental engineering to include air, solid waste, noise, health risk, hazard risk, etc., evolved over time, all of which can today be viewed as a legitimate part of an environmental engineering curriculum. This book’s subject matter of unit operations is therefore only one, but perhaps the most important subject in any interdisciplinary discipline that includes environmental engineering.

This is a book on unit operations … well, sort of. The principles of unit operations were originally set forth soon after the birth of the chemical engineering profession at the turn of the 20^th century and it remains the keystone course in the chemical engineering curriculum. A new kid on the block entered the engineering field around 1950, perhaps spearheaded by the adoption of a sanitary engineering program at Manhattan College, Bronx, NY. The program was later renamed “Environmental Engineering” around 1970. The College also later served as the host of several NSF-funded environmental engineering course development seminars that were directed by the one of the authors, Lou Theodore; and the college also served as home for Lou Theodore (as Professor of Chemical Engineering) for 50 years.

Converting the aforementioned chemical engineering principles/approaches/applications embodied in unit operations to environmental engineering in an optimum manner was not as difficult as the authors originally anticipated. This was, no doubt, due to the clear overlap between the two disciplines.

As noted above, this book is concerned with unit operations, fluid flow, heat transfer, and mass transfer. Unit operations, by definition, are physical processes although there are some that include chemical and biological reactions. The unit operations approach allows both the student and practicing engineer to compartmentalize the various operations that constitute a process. As such, it has enabled the engineer of yesterday and today (and tomorrow) to perform more efficiently. This approach has also allowed the environmental engineer to achieve considerable success in the environmental management field.

The authors’ approach in presenting unit operations material to environmental engineering students is to primarily key on introductory engineering principles so that the reader could then later satisfactorily predict the performance of the various unit operation equipment. In effect, the reader or instructor is provided the opportunity to expand chapter presentations. Although a chapter on Process and Plant Design is included in the introductory part (Part I) of the book, details on equipment design are treated superficially and the subject of plant design is rarely broached.

A comment on chemical reactions is also warranted. Chemical reactions have been defined by some as chemical unit processes. They serve as the backbone of the chemical process industries employing the batch, continuously stirred tank reactors (CSTRs), and tubular flow reactors. However, these chemical unit processes also find application in the wastewater treatment industry. Some of these chemical processes include oxidation, precipitation, neutralization, pH control, disinfection operations, certain coagulation operations, etc. Many of the chemical reactions involve chemicals such as calcium and sodium hydroxide, ferric and aluminum chloride, alum, ferric sulfide, etc. And, as one might suppose, these chemical unit processes are often operated in conjunction with physical unit processes (or unit operations).

Biological unit processes represent another class of chemical reactions that are important to the practicing environmental engineer. The major applications of these biochemical reaction pathways are in wastewater treatment and hazardous waste remediation. The principal biological processes used for wastewater treatment can be divided into two main categories: suspended growth and attached growth (or biofilm) processes. Their successful design and operation requires an understanding of the types of microorganisms involved, the specific reactions that occur, and the environmental factors that affect their performance, their nutritional needs, and their biochemical reaction kinetics.

The decision as to what units and notations to use was difficult. After much deliberation, the authors chose to use engineering - as opposed to metric/SI units, and chemical engineering notation - as opposed to those of other disciplines. This decision was based, to some extent, on the reality that a good part of the book’s content was drawn from the chemical engineering literature, some of which was written by the primary author, Lou Theodore.

The book is divided into five parts.

Part I - Introduction to the Principles of Unit Operations
Part II - Fluid Flow
Part III - Heat Transfer
Part IV - Mass Transfer
Part V - Case Studies

In addition to providing materials on the history of unit operations and a discussion of the relationship among the transport phenomenon/unit operations/unit processes approaches, Part I contains material on traditional introductory engineering principles. These include: thermodynamics, chemical reaction principles, equilibrium versus rate consideration, rate principles, and process and plant design. Part II - Fluid Flow - addresses such subject areas as: fluid classifications, flow mechanisms, flow in conduits, prime movers plus various valve and fittings, sedimentation and centrifugation, porous media and packed beds, filtration, fluidization, ventilation and mixing. Part III - Heat Transfer - contains material concerned with: heat exchangers, waste heat boilers and evaporators, quenchers, psychrometry, humidification, drying, and cooling towers. (Note that the subject of heat transfer was rarely (if ever) included in the environmental engineering curriculum in the early days. For example, in Rich’s classic “Unit Operations in Sanitary Engineering” text, only one of the 15 chapters in the text dealt with heat transfer. That has changed today because of the environmental engineer’s interest in energy, energy conservation, combustion, hazardous waste incineration, global climate change, radiation effects of the sun, etc. In effect, heat transfer has become the new kid on the block in the unit operations arena, and is a topic that every environmental engineer should be proficient in). Part IV of the book - Mass Transfer - covers such topics as: absorption and stripping, adsorption, distillation, liquid-liquid and liquid-solid extraction, and other mass transfer operations. The last part of the book, Part V - Case Studies - provides three applications in each of the three unit operations. An Appendix is also included. An outline of the topics can be found in the Table of Contents.

The reader will note that there is no separate section, part or chapter devoted to biological processes. Rather, they have been integrated into relevant material presented in Parts II and IV. Biological treatment processes (in alphabetical order) that receive treatment include:

Activated Sludge
Aerated Lagoons
Anaerobic Digestion
Composting
Enzyme Treatment
Trickling Filters
Waste Stabilization Ponds

Details on the above seven biological methods were provided earlier by Theodore and McGuinn in “Pollution Prevention,” Van Nostrand Reinhold, New York City, NY, 1992. An extensive analysis of these processes (plus many more) is also available in the work of Metcalf and Eddy, “Wastewater Engineering: Treatment and Reuse,” McGraw-Hill, 4th Edition, New York City, NY, 2004 and L. Rich, “Unit Operations of Sanitary Engineering,” John Wiley & Sons, Hoboken, NJ, 1961.

The authors cannot claim sole authorship to all of the essay material and examples in this text. The present book has evolved from a host of sources, including: notes, homework problems and exam problems prepared by several faculty for a required one-semester, three-credit, “Principles III: Mass Transfer” undergraduate course offered at Manhattan College; L. Theodore and J. Barden, “Mass Transfer”, A Theodore Tutorial, East Williston, NY, 1995; I. Farag, “Fluid Flow,” A Theodore Tutorials, East Williston, NY, 1994; I Farag and J. Reynolds, “Heat Transfer,” A Theodore Tutorials, East Williston, NY, 1995; J. Reynolds, J. Jeris, and L. Theodore, “Handbook for Chemical and Environmental Engineering Calculations,” John Wiley & Sons, Hoboken, NJ, 2004; and J. Santoleri, J. Reynolds, and L. Theodore, “Introduction to Hazardous Waste Management,” 2nd edition, John Wiley & Sons, Hoboken, NJ, 2000. Although the bulk of the material is original and/or taken from sources that the authors have been directly involved with, every effort has been made to acknowledge material drawn from other sources.

It is hoped that this book covers the principles and applications of unit operations 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 unit operations, 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. The authors strongly believe that, while understanding the basic concepts is of paramount importance, this knowledge may be rendered virtually useless to an environmental engineer if he/she cannot apply these concepts in real-world situations. This is the essence of engineering.

Last, but not least, the authors believe that this modest work will help the majority of individuals working and/or studying in the field of environmental engineering to obtain a more complete understanding of unit operations. If you have come this far and read through most of the Preface, you have more than just a passing interest in this subject.

The authors are indebted to the pioneers in the sanitary/environmental engineering field, including such notables as Don O’Connor, Linvil Rich, Wes Eckenfelder, Ross McKinney, Perry McCarty, etc. Pioneers in the environmental management field include James Fenimore Cooper, John Muir, Howard Hesketh, Charlie Pratt, Art Stern, Werner Strauss, etc.

Sincere and special thanks are extended to Haley Seiler of the Civil and Environmental Engineering Department at Utah State University for her invaluable help in the preparation of the draft of the text of this manuscript, and to Ivonne Harris of the Utah Water Research Laboratory for her assistance in preparing all of the figures for the text.

Louis Theodore
East Williston, New York

R. Ryan Dupont
Smithfield, Utah

Kumar Ganesan
Butte, Montana
March, 2017

NOTE: The authors are in the process of preparing an additional resource for this text. An accompanying website containing 15 hours of exams and solutions for the exams will soon be available for those who adopt the book for training and/or academic purposes.

Introduction

How are unit operations related to a unit process? Consider the flow diagram in the figure below. There are three unit operations, 1, 2, and 3. The combination of the three operations that reside in the dashed box is the process or what has come to be referred to as a unit process. Fluid flow, heat transfer, and mass transfer operations fit into the description/definition of unit operations. Chemical and biological operations are, in line with the accepted definitions of unit operations, not considered unit operations. As such, they are reviewed only superficially in this book since they are both treated extensively in the literature. The reader should note that many engineering activities can be classified as:

Physical unit processes,
Chemical unit processes, and/or
Biological unit processes.

Physical unit processes involve the application of physical forces, while chemical and biological unit processes are brought about by the addition of chemicals or chemical reactions, and biochemical reactions, respectively. Physical unit processes have come to be defined as unit operations, the subject title of this book.

The similarity of the physical changes occurring in widely differing industries led to the study of the many steps common to both industry and environmental applications/systems, as the aforementioned unit operations. The unit operations came to be regarded as special cases or combinations of fluid flow, heat transfer and mass transfer.

**Figure I.1** Unit operations versus unit processes.

The chemical reactor is usually at the heart of many processes and it is here that the engineer may simultaneously utilize the principles of fluid flow, heat transfer, and mass transfer, as well as chemical kinetics and thermodynamics, to carry out desired transformations, whether it be for the production of materials or the removal of undesirable pollutants. However, reactions of a chemical or biochemical nature, and the associated equipment, have traditionally not been considered to reside in the unit operations domain.

Underlying nearly every step of a unit process are the principles of fluid flow and heat transfer; the fluid must be transported, and its temperature must be controlled. In a chemical process, where composition is a variable, the principles of mass transfer enter the design of separation and reaction equipment.

This book deals with physical processes, referred to as the aforementioned unit operations, which are common to many chemical and environmental systems. By examining these operations apart from a particular application, students are encouraged to concentrate on fundamental principles. The duplication of topic material normally encountered in “compartmentalized” curricula is avoided, and time should be available to consider a larger variety of operations. The unit operations approach has been employed in chemical engineering education for nearly a century with considerable success, and has recently become an integral part of the environmental engineering curricula.

The book has been written for students with a typical undergraduate background in engineering and the sciences. Comprehension requires only an understanding of freshman chemistry, engineering physics, calculus, and to a lesser extent, differential equations. Details of equipment design are discussed only briefly since several books already published treat this aspect of unit operations with thoroughness and clarity. References to these sources are commonplace in the text. Furthermore, several operations of a less complex nature have been omitted to make room for those ordinarily not considered in courses in environmental engineering but which are of growing importance in the field. As noted earlier, chemical and biochemical operations received minimal treatment.

The material used in this book was taken from both the environmental and chemical engineering field. The use of mixed notation can be confusing, and the choice then was between two alternatives, environmental notation or those of the chemical engineer. As noted in the Preface, the latter was chosen. The use of standard notation in chemical engineering is thought to better serve students in making them familiar with the standard notation used in the literature of the process engineering field. The decision on a unit convention can also be a problem, and the authors have chosen to use English (or engineering) as opposed to SI units as is the standard in much of the process and environmental engineering fields. Comprehensive conversion tables for units are included in the Appendix.

In conclusion, it must be emphasized that this book is not a treatise. Rather, it should be viewed as an introductory textbook dealing primarily with unit operations.