Design of Multiphase Reactors

Foreword xv Preface xvii 1 Evolution of the Chemical Industry and Importance of Multiphase Reactors 1 1.1 Evolution of Chemical Process Industries 1 1.2 Sustainable and Green Processing Requirements in the Modern Chemical Industry 4 1.3 Catalysis 9 1.3.1 Heterogeneous Catalysis 11 1.3.2 Homogeneous Catalysis 16 1.4 Parameters Concerning Catalyst Effectiveness in Industrial Operations 17 1.4.1 Chemoselectivity 19 1.4.2 Regioselectivity 19 1.4.3 Stereoselectivity 19 1.5 Importance of Advanced Instrumental Techniques in Understanding Catalytic Phenomena 20 1.6 Role of Nanotechnology in Catalysis 21 1.7 Click Chemistry 21 1.8 Role of Multiphase Reactors 22 References 23 2 Multiphase Reactors: The Design and Scale-Up Problem 30 2.1 Introduction 30 2.2 The Scale-Up Conundrum 31 2.3 Intrinsic Kinetics: Invariance with Respect to Type/Size of Multiphase Reactor 34 2.4 Transport Processes: Dependence on Type/Size of Multiphase Reactor 34 2.5 Prediction of the Rate-Controlling Step in the Industrial Reactor 35 2.6 Laboratory Methods for Discerning Intrinsic Kinetics of Multiphase Reactions 35 2.6.1 Two-Phase (Gas–Liquid) Reaction 35 2.6.2 Three-Phase (Gas–Liquid–Solid) Reactions with Solid Phase Acting as Catalyst 41 Nomenclature 44 References 45 3 Multiphase Reactors: Types and Criteria for Selection for a Given Application 47 3.1 Introduction to Simplified Design Philosophy 47 3.2 Classification of Multiphase Reactors 48 3.3 Criteria for Reactor Selection 48 3.3.1 Kinetics vis-à-vis Mass Transfer Rates 49 3.3.2 Flow Patterns of the Various Phases 50 3.3.3 Ability to Remove/Add Heat 50 3.3.4 Ability to Handle Solids 53 3.3.5 Operating Conditions (Pressure/Temperature) 54 3.3.6 Material of Construction 54 3.4 Some Examples of Large-Scale Applications of Multiphase Reactors 55 3.4.1 Fischer–Tropsch Synthesis 55 3.4.2 Oxidation of p-Xylene to Purified Terephthalic Acid for Poly(Ethylene Terephthalate) 67 Nomenclature 80 References 81 4 Turbulence: Fundamentals and Relevance to Multiphase Reactors 87 4.1 Introduction 87 4.2 Fluid Turbulence 88 4.2.1 Homogeneous Turbulence 89 4.2.2 Isotropic Turbulence 90 4.2.3 Eddy Size Distribution and Effect of Eddy Size on Transport Rates 90 Nomenclature 91 References 91 5 Principles of Similarity and Their Application for Scale-Up of Multiphase Reactors 93 5.1 Introduction to Principles of Similarity and a Historic Perspective 93 5.2 States of Similarity of Relevance to Chemical Process Equipments 94 5.2.1 Geometric Similarity 95 5.2.2 Mechanical Similarity 96 5.2.3 Thermal Similarity 100 5.2.4 Chemical Similarity 100 5.2.5 Physiological Similarity 101 5.2.6 Similarity in Electrochemical Systems 101 5.2.7 Similarity in Photocatalytic Reactors 102 Nomenclature 102 References 104 6 Mass Transfer in Multiphase Reactors: Some Theoretical Considerations 106 6.1 Introduction 106 6.2 Purely Empirical Correlations Using Operating Parameters and Physical Properties 107 6.3 Correlations Based on Mechanical Similarity 108 6.3.1 Correlations Based on Dynamic Similarity 108 6.4 Correlations Based on Hydrodynamic/Turbulence Regime Similarity 116 6.4.1 The Slip Velocity Approach 116 6.4.2 Approach Based on Analogy between Momentum and Mass Transfer 132 Nomenclature 135 References 138 7A Stirred Tank Reactors for Chemical Reactions 143 7A.1 Introduction 143 7A.1.1 The Standard Stirred Tank 143 7A.2 Power Requirements of Different Impellers 147 7A.3 Hydrodynamic Regimes in Two-Phase (Gas–Liquid) Stirred Tank Reactors 148 7A.3.1 Constant Speed of Agitation 150 7A.3.2 Constant Gas Flow Rate 150 7A.4 Hydrodynamic Regimes in Three-Phase (Gas–Liquid–Solid) Stirred Tank Reactors 153 7A.5 Gas Holdup in Stirred Tank Reactors 155 7A.5.1 Some Basic Considerations 155 7A.5.2 Correlations for Gas Holdup 164 7A.5.3 Relative Gas Dispersion (N/NCD) as a Correlating Parameter for Gas Holdup 165 7A.5.4 Correlations for NCD 166 7A.6 Gas–Liquid Mass Transfer Coefficient in Stirred Tank Reactor 166 7A.7 Solid–Liquid Mass Transfer Coefficient in Stirred Tank Reactor 175 7A.7.1 Solid Suspension in Stirred Tank Reactor 175 7A.7.2 Correlations for Solid–Liquid Mass Transfer Coefficient 191 7A.8 Design of Stirred Tank Reactors with Internal Cooling Coils 194 7A.8.1 Gas Holdup 194 7A.8.2 Critical Speed for Complete Dispersion of Gas 194 7A.8.3 Critical Speed for Solid Suspension 195 7A.8.4 Gas–Liquid Mass Transfer Coefficient 195 7A.8.5 Solid–Liquid Mass Transfer Coefficient 196 7A.9 Stirred Tank Reactor with Internal Draft Tube 196 7A.10 Worked Example: Design of Stirred Reactor for Hydrogenation of Aniline to Cyclohexylamine (Capacity: 25000 Metric Tonnes per Year) 198 7A.10.1 Elucidation of the Output 201 Nomenclature 203 References 206 7B Stirred Tank Reactors for Cell Culture Technology 216 7B.1 Introduction 216 7B.2 The Biopharmaceutical Process and Cell Culture Engineering 224 7B.2.1 Animal Cell Culture vis-à-vis Microbial Culture 224 7B.2.2 Major Improvements Related to Processing of Animal Cell Culture 225 7B.2.3 Reactors for Large-Scale Animal Cell Culture 226 7B.3 Types of Bioreactors 229 7B.3.1 Major Components of Stirred Bioreactor 230 7B.4 Modes of Operation of Bioreactors 230 7B.4.1 Batch Mode 231 7B.4.2 Fed-Batch or Semibatch Mode 232 7B.4.3 Continuous Mode (Perfusion) 233 7B.5 Cell Retention Techniques for Use in Continuous Operation in Suspended Cell Perfusion Processes 233 7B.5.1 Cell Retention Based on Size: Different Types of Filtration Techniques 234 7B.5.2 Separation Based on Body Force Difference 242 7B.5.3 Acoustic Devices 246 7B.6 Types of Cells and Modes of Growth 253 7B.7 Growth Phases of Cells 254 7B.8 The Cell and Its Viability in Bioreactors 256 7B.8.1 Shear Sensitivity 256 7B.9 Hydrodynamics 264 7B.9.1 Mixing in Bioreactors 264 7B.10 Gas Dispersion 273 7B.10.1 Importance of Gas Dispersion 273 7B.10.2 Effect of Dissolved Carbon Dioxide on Bioprocess Rate 275 7B.10.3 Factors That Affect Gas Dispersion 277 7B.10.4 Estimation of NCD 278 7B.11 Solid Suspension 279 7B.11.1 Two-Phase (Solid–Liquid) Systems 279 7B.11.2 Three-Phase (Gas–Liquid–Solid) Systems 280 7B.12 Mass Transfer 281 7B.12.1 Fractional Gas Holdup (εG) 281 7B.12.2 Gas–Liquid Mass Transfer 281 7B.12.3 Liquid–Cell Mass Transfer 283 7B.13 Foaming in Cell Culture Systems: Effects on Hydrodynamics and Mass Transfer 285 7B.14 Heat Transfer in Stirred Bioreactors 287 7B.15 Worked Cell Culture Reactor Design Example 291 7B.15.1 Conventional Batch Stirred Reactor with Air Sparging for Microcarrier-Supported Cells: A Simple Design Methodology for Discerning the Rate-Controlling Step 291 7B.15.2 Reactor Using Membrane-Based Oxygen Transfer 294 7B.15.3 Heat Transfer Area Required 294 7B.16 Special Aspects of Stirred Bioreactor Design 295 7B.16.1 The Reactor Vessel 296 7B.16.2 Sterilizing System 296 7B.16.3 Measurement Probes 296 7B.16.4 Agitator Seals 297 7B.16.5 Gasket and O-Ring Materials 297 7B.16.6 Vent Gas System 297 7B.16.7 Cell Retention Systems in Perfusion Culture 297 7B.17 Concluding Remarks 298 Nomenclature 298 References 301 8 Venturi Loop Reactor 317 8.1 Introduction 317 8.2 Application Areas for the Venturi Loop Reactor 317 8.2.1 Two Phase (Gas–Liquid Reactions) 318 8.2.2 Three-Phase (Gas–Liquid–Solid-Catalyzed) Reactions 319 8.3 Advantages of the Venturi Loop Reactor: A Detailed Comparison 323 8.3.1 Relatively Very High Mass Transfer Rates 323 8.3.2 Lower Reaction Pressure 324 8.3.3 Well-Mixed Liquid Phase 325 8.3.4 Efficient Temperature Control 325 8.3.5 Efficient Solid Suspension and Well-Mixed Solid (Catalyst) Phase 325 8.3.6 Suitability for Dead-End System 326 8.3.7 Excellent Draining/Cleaning Features 326 8.3.8 Easy Scale-Up 326 8.4 The Ejector-Based Liquid Jet Venturi Loop Reactor 326 8.4.1 Operational Features 328 8.4.2 Components and Their Functions 328 8.5 The Ejector–Diffuser System and Its Components 332 8.6 Hydrodynamics of Liquid Jet Ejector 333 8.6.1 Flow Regimes 336 8.6.2 Prediction of Rate of Gas Induction 341 8.7 Design of Venturi Loop Reactor 358 8.7.1 Mass Ratio of Secondary to Primary Fluid 358 8.7.2 Gas Holdup 367 8.7.3 Gas–Liquid Mass Transfer: Mass Transfer Coefficient (kLa) and Effective Interfacial Area (a) 376 8.8 Solid Suspension in Venturi Loop Reactor 385 8.9 Solid–Liquid Mass Transfer 388 8.10 Holding Vessel Size 389 8.11 Recommended Overall Configuration 389 8.12 Scale-Up of Venturi Loop Reactor 390 8.13 Worked Examples for Design of Venturi Loop Reactor: Hydrogenation of Aniline to Cyclohexylamine 390 Nomenclature 395 References 399 9 Gas-Inducing Reactors 407 9.1 Introduction and Application Areas of Gas-Inducing Reactors 407 9.1.1 Advantages 408 9.1.2 Drawbacks 408 9.2 Mechanism of Gas Induction 409 9.3 Classification of Gas-Inducing Impellers 410 9.3.1 1–1 Type Impellers 410 9.3.2 1–2 and 2–2 Type Impellers 416 9.4 Multiple-Impeller Systems Using 2–2 Type Impeller for Gas Induction 429 9.4.1 Critical Speed for Gas Induction 431 9.4.2 Rate of Gas Induction (QG) 431 9.4.3 Critical Speed for Gas Dispersion 434 9.4.4 Critical Speed for Solid Suspension 436 9.4.5 Operation of Gas-Inducing Reactor with Gas Sparging 439 9.4.6 Solid–Liquid Mass Transfer Coefficient (KSL) 440 9.5 Worked Example: Design of Gas-Inducing System with Multiple Impellers for Hydrogenation of Aniline to Cyclohexylamine (Capacity: 25000 Metric Tonnes per Year) 441 9.5.1 Geometrical Features of the Reactor/Impeller (Dimensions and Geometric Configuration as per Section 7A.10 and Figure 9.9 Respectively) 441 9.5.2 Basic Parameters 442 Nomenclature 443 References 446 10 Two- and Three-Phase Sparged Reactors 451 10.1 Introduction 451 10.2 Hydrodynamic Regimes in TPSR 452 10.2.1 Slug Flow Regime 452 10.2.2 Homogeneous Bubble Flow Regime 452 10.2.3 Heterogeneous Churn-Turbulent Regime 454 10.2.4 Transition from Homogeneous to Heterogeneous Regimes 455 10.3 Gas Holdup 457 10.3.1 Effect of Sparger 458 10.3.2 Effect of Liquid Properties 458 10.3.3 Effect of Operating Pressure 460 10.3.4 Effect of Presence of Solids 461 10.4 Solid–Liquid Mass Transfer Coefficient (KSL) 466 10.4.1 Effect of Gas Velocity on KSL 466 10.4.2 Effect of Particle Diameter dP on KSL 467 10.4.3 Effect of Column Diameter on KSL 467 10.4.4 Correlation for KSL 468 10.5 Gas–Liquid Mass Transfer Coefficient (kLa) 468 10.6 Axial Dispersion 472 10.7 Comments on Scale-Up of TPSR/Bubble Columns 474 10.8 Reactor Design Example for Fischer–Tropsch Synthesis Reactor 474 10.8.1 Introduction 474 10.8.2 Physicochemical Properties 475 10.8.3 Basis for Reactor Design Material Balance and Reactor Dimensions 476 10.8.4 Calculation of Mass Transfer Parameters 476 10.8.5 Estimation of Rates of Individual Steps and Determination of the Rate Controlling Step 478 10.8.6 Sparger Design 480 10.9 TPSR (Loop) with Internal Draft Tube (BCDT) 481 10.9.1 Introduction 481 10.9.2 Hydrodynamic Regimes in TPSRs with Internal Draft Tube 481 10.9.3 Gas–Liquid Mass Transfer 482 10.9.4 Solid Suspension 488 10.9.5 Solid–Liquid Mass Transfer Coefficient (KSL) 490 10.9.6 Correlation for KSL 490 10.9.7 Application of BCDT to Fischer–Tropsch Synthesis 491 10.9.8 Application of BCDT to Oxidation of p-Xylene to Terephthalic Acid 492 Nomenclature 493 References 496 Index 505