Hydrodynamics of Gas-Liquid Reactors

Professor Barry Azzopardi is based in the School of Chemical and Environmental Engineering at the University of Nottingham. Barry is responsible for multiphase flow research , with particular focus on phase separation in reaction vessels, drop size measurement in complex systems, demisting, gas cleaning and flow in aero-engine bearing chambers. He has over 70 technical publications.Professor Robert Mudde is based in the Department of Multiscale Physics in the Faculty of Applied Science, Delft University of Technology, The Netherlands. His research interests include bubbly flows, advanced experiments in multiphase flows and multiphase hydrodynamics. He has authored more than 50 refereed journal papers and is an associate editor of the International Journal of Multiphase Flow.S. Lo, CD Adapco, (Computational Engineering Company, London)H. Morvan, Mechanical, Manufacturing and Materials Engineering, University of NottinghamY.Y. Yan, Associate Professor, School of the Built Environment, University of NottinghamDonglin Zhao, Chemical and Environmental Engineering, University of Nottingham

• List of Figures xi List of Tables xixPreface xxiNomenclature xxiii1. Introduction 1Part One2. Bubble Columns 52.1 Introduction 62.2 Types of Bubble Columns 62.3 Introduction of Gas 72.3.1 Methodology of Gas Injection 82.3.2 Bubble Formation and Size Change 112.3.3 Bubble Movement 162.3.3.1 Bubble Shape 162.3.3.2 Bubble Motion 172.3.3.3 Bubble Velocity 172.3.3.4 Effect of Multiple Bubbles 212.3.4 Void Fraction Prediction 222.3.5 Detailed Behaviour of the Flow 332.3.6 Gas-Liquid Mass Transfer 372.3.7 Design of Gas Introduction Arrangement 412.3.8 Worked Example 422.4 Disengagement of Liquid from Gas 432.4.1 Mechanisms of Drop Formation 432.4.2 Drop Capture 442.4.3 Wave Plate Mist Eliminators 472.4.4 Mesh Mist Eliminators 51Questions 54References 563. Sparged Stirred Vessels 613.1 Introduction 623.2 Flow Regimes 633.3 Variations 653.4 Spargers 653.5 Impellers 673.5.1 Disc Turbines 673.5.2 Pitched Blade Turbines 693.5.3 Hydrofoil Impellers 693.5.4 Multiple Impellers 723.6 Baffles 723.7 Power Requirements 733.7.1 Single Impellers 733.7.2 Multiple Impellers 753.7.3 Single-Phase Power 763.8 Gas Fraction 773.9 Mass Transfer 793.9.1 Bubble Size 793.9.2 Interfacial Area 803.9.3 Mass Transfer 813.10 Mixing Times 84Questions 85References 874. Thin Film Reactors 914.1 Introduction 914.2 Falling Film Reactors 924.2.1 Film Thickness 964.2.2 Interfacial Waves 994.2.3 Heat and Mass Transfer 1024.3 Rotating Disc Reactors 1054.3.1 Film Thickness 1054.3.2 Interfacial Waves 1074.3.3 Mass Transfer 1084.4 Two-Phase Tubular Reactors 1094.5 Monolith Reactors 1134.5.1 Micro-Channels 1154.5.2 Flow Phenomena in Micro-Channels 1154.5.3 Numerical Modelling 117Questions 119References 1205. Macroscale Modelling 1255.1 Introduction 1265.2 Eulerian Multiphase Flow Model 1285.2.1 Definition 1285.2.2 Transport Equations 1285.2.2.1 Continuity Equation 1295.2.2.2 Momentum Equation 1295.2.2.3 Energy Equation 1305.2.3 Interfacial Forces 1305.2.3.1 Drag Force 1305.2.3.2 Lift Force 1325.2.3.3 Virtual Mass Force 1325.2.3.4 Turbulent Drag Force 1335.2.3.5 Basset Force 1335.2.3.6 Wall Lubrication Force 1335.2.4 Turbulence Models 1345.2.5 Case Study – Cylindrical Bubble Column 1355.2.6 Homogenous and Mixture Modelling 1355.2.6.1 General Formulation 1365.2.6.2 Mixture Model 1375.3 Poly-Dispersed Flows 1395.3.1 Methods of Moments 1395.3.1.1 Breakup Model 1405.3.1.2 Coalescence Model 1415.3.2 Case Study – Hibiki’s Bubble Column 1425.3.2.1 Numerical Solution Method 1425.3.2.2 Results and Discussion 1425.3.2.3 Summary of Case Study 1485.4 Gassed Stirred Vessels 1495.4.1 Impeller Model 1495.4.2 Multiple Reference Frame 1505.4.3 Multiple Impellers 1505.5 Summary 154Questions 155References 1566. Mesoscale Modelling Using the Lattice Boltzmann Method 1596.1 Introduction 1596.2 Lattice Boltzmann Method and the Advantages 1616.3 Numerical Simulation of Single-Phase Flow and Heat Transfer 1636.3.1 LBM Model 1646.3.2 Treatment for a Curved Boundary 1666.3.3 Numerical Simulation and Results 1676.4 Numerical Simulation of Two-Phase Flow 1696.4.1 Two-Phase Lattice Boltzmann Model 1696.4.2 Vortices Merging in a Two-Phase Spatially Growing Mixing Layer 1756.4.3 Viscous Fingering Phenomena of Immiscible Two-Fluid Displacement 1766.4.4 Bubbles/Drops Flow Behaviour 1786.4.4.1 LBM Method 1786.4.4.2 Correction of Pressure 1816.4.4.3 Boundary Treatment 1816.4.4.4 Results of Two Rising Bubbles Coalescence 1836.4.4.5 Results of Droplet Spreading on Partial Wetting Surface 185References 187Part Two7. Upset Conditions 1937.1 Introduction 1937.2 Active Relief Methods 1947.3 Passive Relief Methods 195References 1998. Behaviour of Vessel Contents and Outflow Calculations 2018.1 Introduction 2018.1.1 Physics of Venting Processes 2018.1.2 Typical Reactions 2028.1.3 Trends and Observations 2038.1.4 Summary of Observations and Measurements of the Level Swell Process 2108.2 Modelling of the Level Swell Process 2128.3 Vent Sizing and Vent Performance Calculations 2168.4 Computer Codes for Level Swell and Venting Calculations 2208.5 Obtaining Necessary Data 2228.6 Performance of Models and Codes 226Appendix 8.A 228Appendix 8.B 230Questions 233References 2359. Choked Flow 2379.1 Introduction 2379.2 Single-Phase Flow 2399.3 Two-Phase Flow 2419.4 Effect of Vent Pipework 250Questions 255References 256Part Three10. Measurement Techniques 25910.1 Bubble Columns 26010.1.1 Gas Hold-Up 26010.1.2 Local Probes: Conductance or Refraction Index 26110.1.2.1 Gas Fraction 26110.1.2.2 Bubble Size and Velocity 26310.1.3 Wire Mesh Sensors 26410.1.4 Photographic Techniques 26610.1.5 Laser Doppler Anemometry (LDA) 26710.1.6 Particle Image Velocimetry (PIV) 26810.1.7 Electrical Tomography Methods (ECT and ERT) 26910.1.8 c and X-Ray Tomography 27310.1.9 CARPT and PEPT 27710.1.10 Acoustic Methods 27910.1.11 Mass Transfer Coefficient 28110.2 Sparged Stirred Tanks 28310.2.1 Power Draw 28310.2.1.1 Strain Gauges 28410.2.1.2 Measurement of Motor Power 28510.2.1.3 Modified Rheometer Method 28510.2.2 Velocity Field 28510.2.3 Void Fraction 28610.2.4 Mixing Time 28610.2.5 Mass Transfer Coefficient 28810.3 Falling Film Reactors 29010.3.1 Film Thickness 29010.3.2 Heat and Mass Transfer 296Questions 300References 302Index 307