Design of Multiphase Reactors

**Details simple design methods for multiphase reactors in the chemical process industries** * Includes basic aspects of transport in multiphase reactors and the importance of relatively reliable and simple procedures for predicting mass transfer parameters * Details of design and scale up aspects of several important types of multiphase reactors * Examples illustrated through design methodologies presenting different reactors for reactions that are industrially important * Includes simple spreadsheet packages rather than complex algorithms / programs or computational aid Design of Multiphase Reactors 5 Copyright 6 Contents 9 Foreword 17 Preface 19 Chapter 1 Evolution of the Chemical Industry and Importance of Multiphase Reactors 23 1.1 Evolution of Chemical Process Industries 23 1.2 Sustainable and Green Processing Requirements in the Modern Chemical Industry 26 1.3 Catalysis 31 1.3.1 Heterogeneous Catalysis 33 1.3.2 Homogeneous Catalysis 38 1.4 Parameters Concerning Catalyst Effectiveness in Industrial Operations 39 1.4.1 Chemoselectivity 41 1.4.2 Regioselectivity 41 1.4.3 Stereoselectivity 41 1.5 Importance of Advanced Instrumental Techniques in Understanding Catalytic Phenomena 42 1.6 Role of Nanotechnology in Catalysis 43 1.7 Click Chemistry 43 1.8 Role of Multiphase Reactors 44 References 45 Chapter 2 Multiphase Reactors: The Design and Scale-Up Problem 52 2.1 Introduction 52 2.2 The Scale-Up Conundrum 53 2.3 Intrinsic Kinetics: Invariance with Respect to Type/Size of Multiphase Reactor 56 2.4 Transport Processes: Dependence on Type/Size of Multiphase Reactor 56 2.5 Prediction of the Rate-Controlling Step in the Industrial Reactor 57 2.6 Laboratory Methods for Discerning Intrinsic Kinetics of Multiphase Reactions 57 2.6.1 Two-Phase (Gas–Liquid) Reaction 57 2.6.2 Three-Phase (Gas–Liquid–Solid) Reactions with Solid Phase Acting as Catalyst 63 Nomenclature 66 References 67 Chapter 3 Multiphase Reactors: Types and Criteria for Selection for a Given Application 69 3.1 Introduction to Simplified Design Philosophy 69 3.2 Classification of Multiphase Reactors 70 3.3 Criteria for Reactor Selection 70 3.3.1 Kinetics vis-à-vis Mass Transfer Rates 71 3.3.2 Flow Patterns of the Various Phases 72 3.3.3 Ability to Remove/Add Heat 72 3.3.4 Ability to Handle Solids 75 3.3.5 Operating Conditions (Pressure/Temperature) 76 3.3.6 Material of Construction 76 3.4 Some Examples of Large-Scale Applications of Multiphase Reactors 77 3.4.1 Fischer–Tropsch Synthesis 77 3.4.2 Oxidation of p-Xylene to Purified Terephthalic Acid for Poly(Ethylene Terephthalate) 89 Nomenclature 102 References 103 Chapter 4 Turbulence: Fundamentals and Relevance to Multiphase Reactors 109 4.1 Introduction 109 4.2 Fluid Turbulence 110 4.2.1 Homogeneous Turbulence 111 4.2.2 Isotropic Turbulence 112 4.2.3 Eddy Size Distribution and Effect of Eddy Size on Transport Rates 112 Nomenclature 113 References 113 Chapter 5 Principles of Similarity and Their Application for Scale-Up of Multiphase Reactors 115 5.1 Introduction to Principles of Similarity and a Historic Perspective 115 5.2 States of Similarity of Relevance to Chemical Process Equipments 116 5.2.1 Geometric Similarity 117 5.2.2 Mechanical Similarity 118 5.2.3 Thermal Similarity 122 5.2.4 Chemical Similarity 122 5.2.5 Physiological Similarity 123 5.2.6 Similarity in Electrochemical Systems 123 5.2.7 Similarity in Photocatalytic Reactors 124 Nomenclature 124 References 126 Chapter 6 Mass Transfer in Multiphase Reactors: Some Theoretical Considerations 128 6.1 Introduction 128 6.2 Purely Empirical Correlations Using Operating Parameters and Physical Properties 129 6.3 Correlations Based on Mechanical Similarity 130 6.3.1 Correlations Based on Dynamic Similarity 130 6.4 Correlations Based on Hydrodynamic/Turbulence Regime Similarity 138 6.4.1 The Slip Velocity Approach 138 6.4.2 Approach Based on Analogy between Momentum and Mass Transfer 154 Nomenclature 157 References 160 Chapter 7A Stirred Tank Reactors for Chemical Reactions 165 7A.1 Introduction 165 7A.1.1 The Standard Stirred Tank 165 7A.2 Power Requirements of Different Impellers 169 7A.3 Hydrodynamic Regimes in Two-Phase (Gas–Liquid) Stirred Tank Reactors 170 7A.3.1 Constant Speed of Agitation 172 7A.3.2 Constant Gas Flow Rate 172 7A.4 Hydrodynamic Regimes in Three-Phase (Gas–Liquid–Solid) Stirred Tank Reactors 175 7A.5 Gas Holdup in Stirred Tank Reactors 177 7A.5.1 Some Basic Considerations 177 7A.5.2 Correlations for Gas Holdup 186 7A.5.3 Relative Gas Dispersion (N/NCD) as a Correlating Parameter for Gas Holdup 187 7A.5.4 Correlations for NCD 188 7A.6 Gas–Liquid Mass Transfer Coefficient in Stirred Tank Reactor 188 7A.7 Solid–Liquid Mass Transfer Coefficient in Stirred Tank Reactor 197 7A.7.1 Solid Suspension in Stirred Tank Reactor 197 7A.7.2 Correlations for Solid–Liquid Mass Transfer Coefficient 213 7A.8 Design of Stirred Tank Reactors with Internal Cooling Coils 216 7A.8.1 Gas Holdup 216 7A.8.2 Critical Speed for Complete Dispersion of Gas 216 7A.8.3 Critical Speed for Solid Suspension 217 7A.8.4 Gas–Liquid Mass Transfer Coefficient 217 7A.8.5 Solid–Liquid Mass Transfer Coefficient 218 7A.9 Stirred Tank Reactor with Internal Draft Tube 218 7A.10 Worked Example: Design of Stirred Reactor for Hydrogenation of Aniline to Cyclohexylamine (Capacity: 25,000 Metric Tonnes per Year) 220 7A.10.1 Elucidation of the Output 223 Nomenclature 225 References 228 Chapter 7B Stirred Tank Reactors for Cell Culture Technology 238 7B.1 Introduction 238 7B.2 The Biopharmaceutical Process and Cell Culture Engineering 246 7B.2.1 Animal Cell Culture vis-à-vis Microbial Culture 246 7B.2.2 Major Improvements Related to Processing of Animal Cell Culture 247 7B.2.3 Reactors for Large-Scale Animal Cell Culture 248 7B.3 Types of Bioreactors 251 7B.3.1 Major Components of Stirred Bioreactor 252 7B.4 Modes of Operation of Bioreactors 252 7B.4.1 Batch Mode 253 7B.4.2 Fed-Batch or Semibatch Mode 254 7B.4.3 Continuous Mode (Perfusion) 255 7B.5 Cell Retention Techniques for Use in Continuous Operation in Suspended Cell Perfusion Processes 255 7B.5.1 Cell Retention Based on Size: Different Types of Filtration Techniques 256 7B.5.2 Separation Based on Body Force Difference 264 7B.5.3 Acoustic Devices 268 7B.6 Types of Cells and Modes of Growth 275 7B.7 Growth Phases of Cells 276 7B.8 The Cell and Its Viability in Bioreactors 278 7B.8.1 Shear Sensitivity 278 7B.9 Hydrodynamics 286 7B.9.1 Mixing in Bioreactors 286 7B.10 Gas Dispersion 295 7B.10.1 Importance of Gas Dispersion 295 7B.10.2 Effect of Dissolved Carbon Dioxide on Bioprocess Rate 297 7B.10.3 Factors That Affect Gas Dispersion 299 7B.10.4 Estimation of NCD 300 7B.11 Solid Suspension 301 7B.11.1 Two-Phase (Solid–Liquid) Systems 301 7B.11.2 Three-Phase (Gas–Liquid–Solid) Systems 302 7B.12 Mass Transfer 303 7B.12.1 Fractional Gas Holdup (εG) 303 7B.12.2 Gas–Liquid Mass Transfer 303 7B.12.3 Liquid–Cell Mass Transfer 305 7B.13 Foaming in Cell Culture Systems: Effectson Hydrodynamics and Mass Transfer 307 7B.14 Heat Transfer in Stirred Bioreactors 309 7B.15 Worked Cell Culture Reactor Design Example 313 7B.15.1 Conventional Batch Stirred Reactor with Air Sparging for Microcarrier-Supported Cells: A Simple Design Methodology for Discerning the Rate-Controlling Step 313 7B.15.2 Reactor Using Membrane-Based Oxygen Transfer 316 7B.15.3 Heat Transfer Area Required 316 7B.16 Special Aspects of Stirred Bioreactor Design 317 7B.16.1 The Reactor Vessel 318 7B.16.2 Sterilizing System 318 7B.16.3 Measurement Probes 318 7B.16.4 Agitator Seals 319 7B.16.5 Gasket and O-Ring Materials 319 7B.16.6 Vent Gas System 319 7B.16.7 Cell Retention Systems in Perfusion Culture 319 7B.17 Concluding Remarks 320 Nomenclature 320 References 323 Chapter 8 Venturi Loop Reactor 339 8.1 Introduction 339 8.2 Application Areas for the Venturi Loop Reactor 339 8.2.1 Two Phase (Gas–Liquid Reactions) 340 8.2.2 Three-Phase (Gas–Liquid–Solid-Catalyzed) Reactions 341 8.3 Advantages of the Venturi Loop Reactor: A Detailed Comparison 345 8.3.1 Relatively Very High Mass Transfer Rates 345 8.3.2 Lower Reaction Pressure 346 8.3.3 Well-Mixed Liquid Phase 347 8.3.4 Efficient Temperature Control 347 8.3.5 Efficient Solid Suspension and Well-Mixed Solid (Catalyst) Phase 347 8.3.6 Suitability for Dead-End System 348 8.3.7 Excellent Draining/Cleaning Features 348 8.3.8 Easy Scale-Up 348 8.4 The Ejector-Based Liquid Jet Venturi Loop Reactor 348 8.4.1 Operational Features 350 8.4.2 Components and Their Functions 350 8.5 The Ejector–Diffuser System and Its Components 354 8.6 Hydrodynamics of Liquid Jet Ejector 355 8.6.1 Flow Regimes 358 8.6.2 Prediction of Rate of Gas Induction 363 8.7 Design of Venturi Loop Reactor 380 8.7.1 Mass Ratio of Secondary to Primary Fluid 380 8.7.2 Gas Holdup 389 8.7.3 Gas–Liquid Mass Transfer: Mass Transfer Coefficient (kLa) and Effective Interfacial Area (a) 398 8.8 Solid Suspension in Venturi Loop Reactor 407 8.9 Solid–Liquid Mass Transfer 410 8.10 Holding Vessel Size 411 8.11 Recommended Overall Configuration 411 8.12 Scale-Up of Venturi Loop Reactor 412 8.13 Worked Examples for Design of Venturi Loop Reactor: Hydrogenation of Aniline to Cyclohexylamine 412 Nomenclature 417 References 421 Chapter 9 Gas-Inducing Reactors 429 9.1 Introduction and Application Areas of Gas-Inducing Reactors 429 9.1.1 Advantages 430 9.1.2 Drawbacks 430 9.2 Mechanism of Gas Induction 431 9.3 Classification of Gas-Inducing Impellers 432 9.3.1 1–1 Type Impellers 432 9.3.2 1–2 and 2–2 Type Impellers 438 9.4 Multiple-Impeller Systems Using 2–2 Type Impeller for Gas Induction 451 9.4.1 Critical Speed for Gas Induction 453 9.4.2 Rate of Gas Induction (QG) 453 9.4.3 Critical Speed for Gas Dispersion 456 9.4.4 Critical Speed for Solid Suspension 458 9.4.5 Operation of Gas-Inducing Reactor with Gas Sparging 461 9.4.6 Solid–Liquid Mass Transfer Coefficient (KSL) 462 9.5 Worked Example: Design of Gas-Inducing System with Multiple Impellers for Hydrogenation of Aniline to Cyclohexylamine (Capacity: 25,000 Metric Tonnes per Year) 463 9.5.1 Geometrical Features of the Reactor/Impeller (Dimensions and Geometric Configuration as per Section 7A.10 and Figure 9.9, Respectively) 463 9.5.2 Basic Parameters 464 Nomenclature 465 References 468 Chapter 10 Two- and Three-Phase Sparged Reactors 473 10.1 Introduction 473 10.2 Hydrodynamic Regimes in TPSR 474 10.2.1 Slug Flow Regime 474 10.2.2 Homogeneous Bubble Flow Regime 474 10.2.3 Heterogeneous Churn-Turbulent Regime 476 10.2.4 Transition from Homogeneous to Heterogeneous Regimes 477 10.3 Gas Holdup 479 10.3.1 Effect of Sparger 480 10.3.2 Effect of Liquid Properties 480 10.3.3 Effect of Operating Pressure 482 10.3.4 Effect of Presence of Solids 483 10.4 Solid–Liquid Mass Transfer Coefficient (KSL) 488 10.4.1 Effect of Gas Velocity on KSL 488 10.4.2 Effect of Particle Diameter dP on KSL 489 10.4.3 Effect of Column Diameter on KSL 489 10.4.4 Correlation for KSL 490 10.5 Gas–Liquid Mass Transfer Coefficient (kLa) 490 10.6 Axial Dispersion 494 10.7 Comments on Scale-Up of TPSR/Bubble Columns 496 10.8 Reactor Design Example for Fischer–Tropsch Synthesis Reactor 496 10.8.1 Introduction 496 10.8.2 Physicochemical Properties 497 10.8.3 Basis for Reactor Design, Material Balance, and Reactor Dimensions 498 10.8.4 Calculation of Mass Transfer Parameters 498 10.8.5 Estimation of Rates of Individual Steps and Determination of the Rate Controlling Step 500 10.8.6 Sparger Design 502 10.9 TPSR (Loop) with Internal Draft Tube (BCDT) 503 10.9.1 Introduction 503 10.9.2 Hydrodynamic Regimes in TPSRs with Internal Draft Tube 503 10.9.3 Gas–Liquid Mass Transfer 504 10.9.4 Solid Suspension 510 10.9.5 Solid–Liquid Mass Transfer Coefficient (KSL) 512 10.9.6 Correlation for KSL 512 10.9.7 Application of BCDT to Fischer–Tropsch Synthesis 513 10.9.8 Application of BCDT to Oxidation of p-Xylene to Terephthalic Acid 514 Nomenclature 515 References 518 Index 527 End User License Agreement 535 "This book covers simple design methods for multiphase reactors in the chemical process industries. It is aimed at providing the process design engineer with simple yet theoretically sound procedures. It can also be used as a text for a specialized course/elective for senior undergraduate and post graduate courses. Different types of multiphase reactors are dealt with on an individual basis including two widely used and important reactors that have not received adequate attention particularly: the ventury loop reactor and stirred reactor for cell culture technology. For each reactor type the book discusses the basic theory, develops quantitative models for reactor design and operation and comments on the state of knowledge." "This resource offers a primer on simple design methods for multiphase reactors in the chemical process industries, particularly the fine chemicals industry. It provides the process design engineer with simple yet theoretically sound procedures. Different types of multiphase reactors are dealt with on an individual basis. The book focuses on the problem of predicting mass transfer rates in these reactors. It also contains finally worked examples that clearly illustrate how a highly complex MPR like the Stirred Tank Reactor (STR) can be designed using simple correlations which need only a scientific calculator"-- Provided by publisher