Contents

1• INTRODUCTION 11.1 Nature and Scope of ChemicalKinetics 11.2 Nature and Scope of ChemicalReaction Engineering 11.3 Kinetics and ChemicalReaction Engineering 21.4 Aspects of Kinetics 3

1.4.1 Rate of Reaction-Definition 31.4.2 Parameters Affecting Rate of Reaction: The Rate Law 41.4.3 Measurement of Rate of Reaction-Preliminary 51.4.4 Kinetics and Chemical Reaction Stoichiometry 61.4.5 Kinetics and Thermodynamics/Equilibrium 141.4.6 Kinetics and Transport Processes 15

1.5 Aspects of ChemicalReaction Engineering 151.5.1 Reactor Design and Analysis of Performance 151.5.2 Parameters Affecting Reactor Performance 161.5.3 Balance Equations 161.5.4 An Example of an Industrial Reactor 18

1.6 Dimensions andUnits 191.7 Plan ofTreatment in FollowingChapters 21

1.7.1 Organization of Topics 211.7.2 Use of Computer Software for Problem Solving 21

1.8 Problems for Chapter1 22

2 • KINETICS AND IDEAL REACTOR MODELS 252.1 Time Quantities 252.2 Batch Reactor (BR) 26

2.2.1 General Features 262.2.2 Material Balance; Interpretation of ri 27

2.3 ContinuousStirred-TankReactor (CSTR) 292.3.1 General Features 292.3.2 Material Balance; Interpretation of ri 31

2.4 Plug-FlowReactor (PFR) 332.4.1 General Features 332.4.2 Material Balance; Interpretation of ri 34

2.5 Laminar-FlowReactor (LFR) 362.6 Summaryof Results for Ideal Reactor Models 382.7 StoichiometricTable 392.8 Problems for Chapter2 40

3 • EXPERIMENTAL METHODS IN KINETICS:MEASUREMENT OF RATE OF REACTION 423.1 Featuresof a Rate Law:Introduction 42

3.1.1 Separation of Effects 423.1.2 Effect of Concentration: Order of Reaction 423.1.3 Effect of Temperature: Arrhenius Equation; Activation Energy 44

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3.2 ExperimentalMeasurements:General Considerations 453.3 ExperimentalMethods to FoUowthe Extent of Reaction 46

3.3.1 Ex-situ and In-situ Measurement Techniques 463.3.2 Chernical Methods 463.3.3 Physical Methods 473.3.4 Other Measured Quantities 48

3.4 ExperimentalStrategiesfor DeterminingRate Parameters 483.4.1 Concentration-Related Parameters: Order of Reaction 493.4.2 Experimental Aspects of Measurement of Arrhenius Parameters A and EA 57

3.5 Notes on Methodology for ParameterEstimation 573.6 Problems for Chapter3 61

4 • DEVELOPMENT OF THE RATE LAW FOR A SIMPLE SYSTEM 644.1 The Rate Law 64

4.1.1 Form of Rate Law Used 644.1.2 Empirical versus Fundamental Rate Laws 654.1.3 Separability versus Nonseparability of Effects 66

4.2 Gas-Phase Reactions:Choice of ConcentrationUnits 664.2.1 Use of Partial Pressure 664.2.2 Rate and Rate Constant in Terms of Partial Pressure 674.2.3 Arrhenius Parameters in Terms of Partial Pressure 68

4.3 Dependence of Rate on Concentration 694.3.1 First-Order Reactions 694.3.2 Second-Order Reactions 714.3.3 Third-Order Reactions 724.3.4 Other Orders of Reaction 754.3.5 Comparison of Orders of Reaction 754.3.6 Product Species in the Rate Law 78

4.4 Dependence of Rate on Temperature 794.4.1 Determination of Arrhenius Parameters 794.4.2 Arrhenius Parameters and Choice of Concentration Units for Gas-Phase

Reactions 804.5 Problems for Chapter4 80

5 • COMPLEX SYSTEMS 875.1 Typesand Examplesof Complex Systems 87

5.1.1 Reversible (Opposing) Reactions 875.1.2 Reactions in Parallel 885.1.3 Reactions in Series 885.1.4 Combinations of Complexities 885.1.5 Compartmental or Box Representation of Reaction Network 89

5.2 Measuresof Reaction Extent and Selectivity 905.2.1 Reaction Stoichiometry and Its Significance 905.2.2 Fractional Conversion of a Reactant 915.2.3 Yield of a Product 915.2.4 Overall and Instantaneous Fractional Yield 925.2.5 Extent of Reaction 935.2.6 Stoichiometric Table for Complex System 93

5.3 ReversibleReactions 945.3.1 Net Rate and Forms of Rate Law 945.3.2 Thermodynamic Restrictions on Rate and on Rate Laws 955.3.3 Determination of Rate Constants 975.3.4 Optimal T for Exothermic Reversible Reaction 99

5.4 ParaUelReactions 1005.5 Series Reactions 103

Contents xiii

5.6 ComplexitiesCombined 1065.6.1 Concept of Rate-Determining Step (rds) 1065.6.2 Determination of Reaction Network 106

5.7 Problems for Chapter5 108

6 • FUNDAMENTALS OF REACTION RATES 1156.1 PreliminaryConsiderations 115

6.1.1 Relating to Reaction-Rate Theories 1156.1.2 Relating to Reaction Mechanisms and Elementary Reactions 116

6.2 Description of ElementaryChemicalReactions 1176.2.1 Types of Elementary Reactions 1176.2.2 General Requirements for Elementary Chemical Reactions 120

6.3 Energy in Molecules 1206.3.1 Potential Energy in Molecules-Requirements for Reaction 1206.3.2 Kinetic Energy in Molecules 126

6.4 SimpleCollisionTheory of Reaction Rates 1286.4.1 Simple Collision Theory (SCT) of Bimolecular Gas-Phase Reactions 1296.4.2 Collision Theory of Unimolecular Reactions 1346.4.3 Collision Theory of Bimolecular Combination Reactions; Termolecular

Reactions 1376.5 TransitionState Theory (TST) 139

6.5.1 General Features of the TST 1396.5.2 Thermodynamic Formulation 1416.5.3 Quantitative Estimates of Rate Constants Using TST with Statistical Mechanics 1436.5.4 Comparison of TST with SCT 145

6.6 ElementaryReactions InvolvingOtherThan Gas-PhaseNeutral Species 1466.6.1 Reactions in Condensed Phases 1466.6.2 Surface Phenomena 1476.6.3 Photochemical Elementary Reactions 1496.6.4 Reactions in Plasmas 150

6.7 Summary 1516.8 Problems for Chapter6 152

7 • HOMOGENEOUS REACTION MECHANISMS AND RATE LAWS 1547.1 SimpleHomogeneous Reactions 155

7.1.1 Types of Mechanisms 1557.1.2 Open-Sequence Mechanisms: Derivation of Rate Law from Mechanism 1557.1.3 Closed-Sequence Mechanisms; Chain Reactions 1577.1.4 Photochemical Reactions 163

7.2 Complex Reactions 1647.2.1 Derivation of Rate Laws 1647.2.2 Computer Modeling of Complex Reaction Kinetics 165

7.3 PolymerizationReactions 1657.3.1 Chain-Reaction Polymerization 1667.3.2 Step-Change Polymerization 168

7.4 Problems for Chapter7 170

8 • CATALYSIS AND CATALYTIC REACTIONS 1768.1 Catalysisand Catalysts 176

8.1.1 Nature and Concept 1768.1.2 Types of Catalysis 1788.1.3 General Aspects of Catalysis 179

8.2 MolecularCatalysis 1828.2.1 Gas-Phase Reactions 1828.2.2 Acid-Base Catalysis 183

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8.2.3 Other Liquid-Phase Reactions 1868.2.4 Organometallic Catalysis 186

8.3 Autocatalysis 1878.4 Surface Catalysis: Intrinsic Kinetics 191

8.4.1 Surface-Reaction Steps 1918.4.2 Adsorption Without Reaction: Langmuir Adsorption Isotherm 1928.4.3 Langmuir-Hinshelwood (LH) Kinetics 1958.4.4 Beyond Langmuir-Hinshelwood Kinetics 197

8.5 Heterogeneous Catalysis:Kinetics in Porous Catalyst Particles 1988.5.1 General Considerations 1988.5.2 Particle Density and Voidage (Porosity) 1998.5.3 Modes of Diffusion; Effective Diffusivity 1998.5.4 Particle Effectiveness Factor TJ 2018.5.5 Dependence of TJ on Temperature 2108.5.6 Overall Effectiveness Factor TJo 212

8.6 Catalyst Deactivation and Regeneration 2148.6.1 Fouling 2148.6.2 Poisoning 2158.6.3 Sintering 2158.6.4 How Deactivation Affects Performance 2168.6.5 Methods for Catalyst Regeneration 216

8.7 Problems for Chapter 8 218

9 • MULTIPHASE REACTING SYSTEMS 2249.1 Gas-Solid (Reactant) Systems 224

9.1.1 Examples of Systems 2249.1.2 Constant-Size Particle 2259.1.3 Shrinking Particle 237

9.2 Gas-Liquid Systems 2399.2.1 Examples of Systems 2399.2.2 Two-FilmMass-Transfer Model for Gas-Liquid Systems 2409.2.3 Kinetics Regimes for Two-FilmModel 242

9.3 Intrinsic Kinetics of Heterogeneous Reactions Involving Solids 2559.4 Problems for Chapter 9 257

10 • BIOCHEMICAL REACTIONS: ENZYME KINETICS 26110.1 Enzyme Catalysis 261

10.1.1 Nature and Examples of Enzyme Catalysis 26110.1.2 Experimental Aspects 263

10.2 Models of Enzyme Kinetics 26410.2.1 Michaelis-Menten Model 26410.2.2 Briggs-Haldane Model 266

10.3 Estimation of Km and Vmax 26710.3.1 Linearized Form of the Michaelis-Menten Equation 26710.3.2 Linearized Form of the Integrated Michaelis-Menten Equation 26910.3.3 Nonlinear Treatment 269

10.4 Inhibition and Activation in Enzyme Reactions 26910.4.1 Substrate Effects 27010.4.2 External Inhibitors and Activators 272

10.5 Problems for Chapter 10 276

11 • PRELIMINARY CONSIDERATIONS IN CHEMICAL REACTIONENGINEERING 27911.1 Process Design and Mechanical Design 279

11.1.1 Process Design 27911.1.2 Mechanical Design 283

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11.2 Examples of Reactors for Illustration of Process Design Considerations 28311.2.1 Batch Reactors 28311.2.2 Stirred-Tank Flow Reactors 28411.2.3 Tubular Flow Reactors 28411.2.4 Fluidized-Bed Reactors 29011.2.5 Other Types of Reactors 291

11.3 Problems for Chapter 11 292

12 • BATCH REACTORS (BR) 29412.1 Uses of Batch Reactors 29412.2 Batch Versus Continuous Operation 29512.3 Design Equations for a Batch Reactor 296

12.3.1 General Considerations 29612.3.2 Isothermal Operation 30012.3.3 NonisothermalOperation 30412.3.4 Optimal Performance for Maximum Production Rate 307

12.4 Semibatch and Semicontinuous Reactors 30912.4.1 Modes of Operation: Semibatch and Semicontinuous Reactors 30912.4.2 Advantages and Disadvantages (Semibatch Reactor) 31012.4.3 Design Aspects 311

12.5 Problems for Chapter 12 313

13 • IDEAL FLOW 31713.1 Terminology 31713.2 Types of Ideal F1ow; Closed and Open Vessels 318

13.2.1 Backmix Flow (BMF) 31813.2.2 Plug Flow (PF) 31813.2.3 Laminar Flow (LF) 31813.2.4 Closed and Open Vessels 318

13.3 Characterization of F10w By Age-Distribution Functions 31913.3.1 Exit-Age Distribution Function E 31913.3.2 Cumulative Residence-Time Distribution Function F 32113.3.3 Washout Residence-Time Distribution Function W 32213.3.4 Internal-Age Distribution Function I 32213.3.5 Holdback H 32213.3.6 Summary of Relationships Among Age-Distribution Functions 32213.3.7 Moments of Distribution Functions 323

13.4 Age- Distribution Functions for Ideal F10w 32513.4.1 Backmix Flow (BMF) 32513.4.2 Plug Flow (PF) 32713.4.3 Laminar Flow (LF) 33013.4.4 Summary of Results for Ideal Flow 332

13.5 Segregated F10w 33213.6 Problems for Chapter 13 333

14 • CONTINUOUS STIRRED-TANK REACTORS (CSTR) 33514.1 Uses of a CSTR 33614.2 Advantages and Disadvantages of a CSTR 33614.3 Design Equations for a Single-Stage CSTR 336

14.3.1 General Considerations; Material and Energy Balances 33614.3.2 Constant-Density System 33914.3.3 Variable-Density System 34414.3.4 Existence of Multiple Stationary States 347

14.4 MuItistage CSTR 35514.4.1 Constant-Density System; Isothermal Operation 35714.4.2 OptimalOperation 358

14.5 Problems for Chapter 14 361

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15 • PLUG FLOW REACTORS (PFR) 36515.1 Uses of a PFR 36515.2 Design Equations for a PFR 366

15.2.1 General Considerations; Material, Energy and Momentum Balances 36615.2.2 Constant-Density System 37015.2.3 Variable-Density System 376

15.3 Recycle Operation of a PFR 38015.3.1 Constant-Density System 38115.3.2 Variable-Density System 386

15.4 Combinations of PFRs: Configurational Effects 38715.5 Problems for Chapter 15 389

16 • LAMINAR FLOW REACTORS (LFR) 39316.1 Uses of an LFR 39316.2 Design Equations for an LFR 394

16.2.1 General Considerations and Material Balance 39416.2.2 Fractional Conversion and Concentration (Profiles) 39516.2.3 Size of Reactor 39716.2.4 Results for SpecificRate Laws 39716.2.5 Summary of Results for LFR 39916.2.6 LFR Performance in Relation to SFM 400

16.3 Problems for Chapter 16 400

17 • COMPARISONS AND COMBINATIONS OF IDEAL REACTORS 40217.1 Single-Vessel Comparisons 402

17.1.1 BR and CSTR 40217.1.2 BR and PFR 40417.1.3 CSTR and PFR 40517.1.4 PFR, LFR, and CSTR 406

17.2 Multiple- Vessel Configurations 40817.2.1 CSTRs in Parallel 40917.2.2 CSTRs in Series: RTD 41017.2.3 PFR and CSTR Combinations in Series 413

17.3 Problems for Chapter 17 418

18 • COMPLEX REACTIONS IN IDEAL REACTORS 42218.1 Reversible Reactions 42218.2 Parallel Reactions 42618.3 Series Reactions 429

18.3.1 Series Reactions in a BR or PFR 42918.3.2 Series Reactions in a CSTR 430

18.4 Choice of Reactor and Design Considerations 43218.4.1 Reactors for Reversible Reactions 43318.4.2 Reactors for Parallel-Reaction Networks 43518.4.3 Reactors for Series-Reaction Networks 43718.4.4 Reactors for Series-Parallel Reaction Networks 441

18.5 Problems for Chapter 18 445

19 • NONIDEAL FLOW 45319.1 General Features of Nonideal F10w 45319.2 Mixing: Macromixing and Micromixing 45419.3 Characterization of Nonideal F10win Terms of RTD 455

19.3.1 Applications of RTD Measurements 45519.3.2 Experimental Measurement of RTD 455

Contents xvii

19.4 One-Parameter Models for Nonideal Flow 47119.4.1 Tanks-in-Series (TIS) Model 47119.4.2 Axial Dispersion or Dispersed Plug Flow (DPF) Model 48319.4.3 Comparison of DPF and TIS Models 490

19.5 Problems for Chapter 19 490

20 • REACTOR PERFORMANCE WITH NONIDEAL FLOW 49520.1 Tanks-in-Series (TIS) Reactor Model 49520.2 Axial Dispersion Reactor Model 49920.3 Segregated-F1ow Reactor Model (SFM) 50120.4 Maximum-Mixedness Reactor Model (MMM) 50220.5 Performance Characteristics for Micromixing Models 50420.6 Problems for Chapter 20 508

21 • FIXED-BED CATALYTIC REACTORS FOR FLUID-SOLIDREACTIONS 5U21.1 Examples of Reactions 51221.2 Types of Reactors and Modes of Operation

21.2.1 Reactors for Two-Phase Reactions 51421.2.2 Flow Arrangement 51421.2.3 Thermal and Bed Arrangement

21.3 Design Considerations 51621.3.1 Considerations of Particle and Bed Characteristics21.3.2 Fluid-Particle Interaction; Pressure Drop (-tlP)21.3.3 Considerations Relating to a Reversible Reaction

21.4 A Classification of Reactor Models 52321.5 Pseudohomogeneous, One-Dimensional, Plug-F1ow Model

21.5.1 Continuity Equation 52721.5.2 Optimal Single-Stage Operation21.5.3 Adiabatic Operation 52921.5.4 Nonadiabatic Operation 542

21.6 Heterogeneous, One-Dimensional, Plug-F1ow Model21.7 One-Dimensional Versus Two-Dimensional Models21.8 Problems for Chapter 21 546

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22 • REACTORS FOR FLUID-SOLID (NONCATALYTIC) REACTIONS 55222.1 Reactions and Reaction Kinetics Models 55222.2 Reactor Models 553

22.2.1 Factors Affecting Reactor Performance 55322.2.2 Semicontinuous Reactors 55322.2.3 Continuous Reactors 55422.2.4 Examples of Continuous Reactor Models 55622.2.5 Extension to More Complex Cases 563

22.3 Problems for Chapter 22 566

23 • FLUIDIZED-BED AND OTHER MOVING-PARTICLE REACTORS FORFLUID-SOLID REACTIONS 56923.1 Moving-Particle Reactors 570

23.1.1 Some Types 57023.1.2 Examples of Reactions 57223.1.3 Advantages and Disadvantages 57323.1.4 Design Considerations 574

23.2 Fluid-Particle Interactions 57423.2.1 Upward Flow of Fluid Through Solid Particles: (- tlP) Regimes 57523.2.2 Minimum Fluidization Velocity (Um!) 575

xviii Contents

23.2.3 Elutriation and Terminal Velocity (u,) 57723.2.4 Comparison of um! and u, 578

23.3 HydrodynamicModels of Fluidization 57923.3.1 Two-Region Model (Class (1» 57923.3.2 Kunii-Levenspiel (KL) Bubbling-Bed Model (Class (2» 580

23.4 Fluidized-BedReactor Models 58423.4.1 KL Model for Fine Particles 58423.4.2 KL Model for Intermediate-Size Particles 59223.4.3 Model for Large Particles 59523.4.4 Reaction in Freeboard and Distributor Regions 595

23.5 Problems for Chapter23 596

24 • REACTORS FOR FLUID-FLUID REACTIONS 59924.1 Types of Reactions 599

24.1.1 Separation-Process Point of View 59924.1.2 Reaction-Process Point of View 599

24.2 Typesof Reactors 60024.2.1 Tower or Column Reactors 60024.2.2 Tank Reactors 602

24.3 Choice of Toweror TankReactor 60224.4 TowerReactors 603

24.4.1 Packed-Tower Reactors 60324.4.2 Bubble-Column Reactors 608

24.5 TankReactors 61424.5.1 Continuity Equations for Tank Reactors 61424.5.2 Correlations for Design Parameters for Tank Reactors 615

24.6 Trickle-BedReactor:Three-PhaseReactions 61824.7 Problems for Chapter24 619

APPENDIX A 623A.1 Common ConversionFactorsfor Non-SI Units to SI Units 623A.2 Valnes of PhysicochemicalConstants 623A.3 StandardSI Prefixes 624

APPENDIX B: BIBLIOGRAPHY 625B.1 Books on ChemicalReactors 625B.2 Books on ChemicalKinetics and Catalysis 626

APPENDIX C:ANSWERS TO SELECTED PROBLEMS 627

APPENDIX D: USE OF E-Z SOLVE FOR EQUATION SOLVING ANDPARAMETER ESTIMATION 635

NOMENCLATURE 643

REFERENCES 652

INDEXES 657