Micro Process Engineering

Transcription

1 Micro Process Engineering A Comprehensive Handbook Volume 1: Fundamentals, Operations and Catalysts Edited by Volker Hessel, Albert Renken, Jaap C. Schouten, andjun-lchi Yoshida WILEY- VCH WILEY-VCH Verlag GmbH & Co. KGaA

2 Contents Preface XV About the Editors List of Contributors XVII XIX Part I Fluid Dynamics in Microchannels 1 1 Multiphase Flow 3 Axel Günther and Michiel T. Kreutzer 1.1 Introduction Fundamentals of Multiphase Flow Properties of Fluids and Interfaces MicroChannel Surface Characteristics and Wetting Scaling of Forces Surface Tension Variations Particles and Fluid Interfaces Classification of Phase Distributions Dynamic Behavior of Multiphase Microflows Flow Instabilities Capillary Instability Deformation of Stratified Liquid Layers Multiphase Flow Regimes Formation of Multiphase Flow Susceptibility of Multiphase Flow to Pressure Fluctuations Separation of Phases Role of Channel Geometries Experimental and Numerical Techniques Numerical Experimental Brightfield Microscopy Fluorescence Microscopy Particle Tracking and Particle Image Velocimetry 23 Micro Process Engineering, Vol.1: Fundamentals, Operations and Catalysts Edited by V. Hessel, A. Renken, J.C. Schouten, and J.-I. Yoshida Copyright 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim ISBN:

3 VI Contents Confocal Microscopy Flow Sensors Magnetic Resonance Imaging X-ray Tomography Annular and Stratified Two-phase Flows Droplet and Bubble Flows Lubrication Analysis Pressure Drop in Segmented-flow Microfluidic Networks Practical Aspects of Microfluidic Networks Parallel Scaling Using Multiphase Flows for Controlling Fluid Paths 30 References 32 2 Microfluidic Networks 41 Norbert Kockmann 2.1 Introduction Fluid Mechanics Basic Channel Structures Network Design Lumped Element Modeling Parallel Channel Devices Headers and Manifold for Plate Stacks Conclusion 56 References 58 3 Boiling and Two-phase Flow in Microchannels 61 John R. Thome and Cherhardt Ribatski 3.1 Introduction Macro-to-Microscale Transition Flow Patterns in Microscale Channels Pressure Drop Boiling Heat Transfer Critical Heat Flux Two-phase Flow Instabilities Prediction Methods Frictional Pressure Drop Heat Transfer Critical Heat Flux 82 References 87 4 Microscale Flow Visualization 93 Marko Hoffmann, Michael Schlüter, and Norbert Räbiger 4.1 Introduction Fundamentals Visualization of Flow Fields in Micro- and Minichannels 95

4 Contents VII Microparticle Image Velocimetry ( i-piv) Correlation Averaging Method D Reconstruction Accuracy of (i-piv Measurements Depth of Correlation Brownian Motion Extension of Common u-piv for Enhancement of Spatial and Temporal Resolution Multiphase Flow Confocal Microparticle Image Velocimetry Stereoscopic Microparticle Image Velocimetry D Particle Tracking Velocimetry Visualization of Concentration and Temperature Fields in Micro- and Minichannels Analysis of Concentration Fields Analysis of Temperature Fields Visualization of Mixing Processes Without Chemical Reactions Visualization of Reactive Mixing Conclusion 113 References Modeling of Microfluidic Devices 117 David F. Fletcher, Brian S. Haynes, Joelle Aubin, and Catherine Xuereb 5.1 Introduction Characteristics of Microsystems Non-continuum Effects Laminar Flow Surface Roughness Viscous Energy Dissipation Gravitational Effects Electric Effects Surface Tension Effects WaH Slip Effects The Importance of Appropriate Solution Methods Conventional Navier-Stokes Solvers Numerical Diffusion Interfacial Surface Location and Parasitic Currents Heat Transfer Simulations Advanced Solution Methods Single-phase Simulations Heat Transfer Enhancement Mixing Modeling of Mass Transfer and Chemical Reaction Multi-phase Simulations Taylor Bubble Simulations 134

5 5.5.2 Droplet Simulations Summary and Perspective 138 References 139 Part II Mixing in Microsystems Characterization of Mixing and Segregation in Homogeneous Flow Systems 147 Laurent Falk and Jean-Marc Commenge 6.1 Introduction Mixing Principles and Features of Microsystems Molecular Diffusion Mixing in a Shear Field Application to Mixing in Microchannels Chaotic Mixers Additional Readings: Chaotic Mixing Model in Microchannels Mixing Efficiency Experimental Mixing Characterization Physical Methods Chemical Methods Villermaux-Dushman Reaction Mixing Time Comparison of Performances of Micromixers Conclusions 170 References Passive and Active Micromixers 175 Zhigang Wu and Nam-Trung Nguyen 7.1 Introduction Passive Micromixers Parallel Lamination Micromixers Serial Lamination Micromixers Micromixers Based on Chaotic Advection Chaotic Advection at High Reynolds Numbers Chaotic Advection at Intermediate Reynolds Numbers Chaotic Advection at Low Reynolds Numbers Droplet Micromixers Active Micromixers Pressure-induced Disturbance Electrohydrodynamic Disturbance Magnetohydrodynamic Disturbance Acoustic Disturbance Thermal Disturbance Fabrication Methods 194

6 7.5 Conclusion 195 References Mixing and Contacting of Heterogeneous Systems 205 Asterios Gavriilidis and Panagiota Angeli 8.1 Gas-liquid Systems Segmented Flow Contactors Bubble Formation and Length Hydrodynamics Bubble Shape and Film Thickness Pressure Drop Mixing and Mass Transfer Phase Separation Multichannel Systems Packed MicroChannel Contactors Foam and Bubble Suspension Microcontactors T-type Mixing Section Geometries Flow Focusing Mixing Section Geometries Multichannel Systems Dispersion Effects Overlapping MicroChannel and Micromesh Contactors Falling Film MicroChannel Contactor Non-miscible Liquid-Liquid Systems Segmented Flow Contactors Slug/Plug Formation Hydrodynamics and Mixing Pressure Drop Liquid-Liquid Dispersion Microcontactors T-type and Co-flow Mixing Section Geometries Flow Focusing Geometries Multichannel Systems Overlapping MicroChannel and Micromesh Contactors 240 References 243 Part III Heat/Mass Transfer Heat Transfer in Homogeneous Systems 255 Franz Trachsel and Philipp Rudolf von Rohr 9.1 Introduction Continuum Assumption Gases Liquids Heat Transfer in Homogeneous Microfluidic Systems Pronounced Effects in MicroChannel Heat Transfer 261

7 X Contents Axial Heat Conduction in the Fluid Conjugate Heat Transfer Surface Roughness Viscous Dissipation Variation of Thermophysical Properties Electric Double Layer Entrance Region Measurement Accuracy Conventional Heat Transfer Correlations for Macroscale Tubes and Channels Developing Hydrodynamic Regions of Laminar Flow Developing Thermal Flow Fully Developed Laminar Flow Constant Wall Temperature Constant Heat Flux Turbulent Flow Transition Regime 2300 < Re < Conclusion 274 References Transport Phenomena in Microscale Reacting Flows 283 Niket S. Kaisare, Ceorgios D. Stefanidis, and Dionisios C. Vlachos 10.1 Introduction Spatial Gradients in Microchannels Axial Thermal Gradients Transverse External Thermal Gradients Transverse External Mass Transfer Internal Heat and Mass Transfer Thermal Radiation in Microchannels Transverse Heat and Mass Transfer Correlations Homogeneous Microburners Effect of Transverse Transport on Flame Stability Transverse Heat Transfer and Nusselt Number Catalytic Microreactors Conclusions 300 References Fluid-Fluid and Fluid-Solid Mass Transfer 303 Michiel T. Kreutzer and Axel Günther 11.1 Introduction Relevance Basics, Relevant Time Scales Stable Fluid Interfaces: Annular Flows and Falling Films Droplet/Bubble Segmented Flows Fluid-Fluid Mass Transfer Without Reaction at the Wall 311

8 Continuous Phase to Wall Mass Transfer Disperse Phase to Wall Mass Transfer Complex Geometries - Packed Beds and Foams 317 References 319 Part IV Microstructured Devices for Purification and Separation Processes Extraction 325 Nobuaki Aoki and Kazuhiro Mae 12.1 Introduction Parallel Flow of Two Immiscible Phases Instances of Extraction Systems and Devices Using Parallel Flow Surface Modification of Channel Geometry for Stabilizing Parallel Flow Application in Organic Synthesis Droplet Manipulation Devices for Continuous Generation of Dispersed Droplets Coalescence of Droplets in Dispersions Precise Operation of Individual Droplets Liquid-liquid Slug Flow Extraction Process Based on Slug Flow Quantitative Study of Mass Transfer in Slug Flow Application of Mass Transfer in Slug Flow to Organic Synthesis Conclusion 341 References Capillary Electrochromatography 347 Hans-Joerg Bart 13.1 Introduction Theory Stationary Phases o-cec Phases Granular Packed Columns Monolithic Phases Chip Electrochromatography Conclusions and Perspectives 358 References 358 Part V Microstructured Reactors Homogeneous Reactions 367 Volker Hessel and Patrick Lob 14.1 Benefits 367

9 XII Contents Reaction Engineering Benefits Process Engineering Benefits Reactor Concepts - the Tools for Process Intensification Micromixers, Micro Heat Exchangers and Minitubes/Capillaries Integrated Reactors Reaction Optimization Process Parameters with Impact on Reactor Performance Residence Time Distribution RTD Studies on Liquid-phase Flows RTD Studies on Gas-phase Flows Impact of Mixing Impact of Heat Exchange Impact of Electromagnetic Waves and Alternative Energies Process Design Combined Reaction-Separation Multi-step Reactions Novel Process Windows High Temperatures - Rate Acceleration High Pressures - Transition State Volume Effects Solventless and Solvent-free Operation Exploration into Explosive and Thermal Runaway Regimes From Laboratory to Production Scale - Scale-out Numbering-up Internal Numbering-up or Equaling-up External Numbering-up: Device Parallelization Smart Scale-up Multi-scale Architecture 390 References Heterogeneous Multiphase Reactions 395 Madhvanand N. Kashid, David W. Agar, Albert Renken, and Lioubov Kiwi-Minsker 15.1 Introduction General Criteria for Reactor Choice and Design Fluid-Solid Reactors Pressure Drop Residence Time Distribution Mass Transfer and Chemical Reaction Fluid-Fluid Reactors Gas-Liquid Systems Pressure Drop Residence Time Distribution Mass Transfer and Film Saturation Liquid-Liquid Systems Pressure Drop 419

10 Contents XIII Residence Time Distribution Chemical Reaction in Liquid-Liquid Systems Three-phase Reactions Gas-Liquid-Solid Continuous-phase Microstructured Reactors Dispersed-phase Microstructured Reactors Gas-Liquid-Liquid Systems Conclusion 431 References Photoreactors 441 Roger Gorges and Andreas Kirsch 16.1 Photochemical Reactions Single-phase Photochemical Reactions Multi-phase Photochemical Reactions Immobilized Photocatalysts Conclusion 455 References Microstructured Reactors for Electrochemical Synthesis 459 Sabine Rode and Frangois Lapicque 17.1 Fundamentals of Electrochemical Processes Electrode Reaction Stoichiometries and Faraday's Law Electrode Potentials and Gibbs Free Energy Change of the Overall Reaction Kinetics and Mass Transfer Limitations of the Electrode Reaction Process Performance Criteria Specific Energy Consumption and Cell Voltage Ohmic Drop and Heat Generation Electrochemical Equipment and Process Flow Schemes Some Overall Process Options Divided and Undivided Cells Direct and Indirect Electrosynthesis Simple and Paired Electrosynthesis Typical Commercial Cells Tank Cells Filterpress-type Flow Cells Cells with Parallel Electrodes and a Millimeter or Submillimeter Inter-electrode Gap 466 Y7.2.2A Cells with Non-parallel Dissymmetric Electrodes Process Flow Schemes Microreactors in Electrochemical Synthesis Process Intensification Mechanisms Enhancement of the Mass Transfer Rates Coupling of the Electrode Processes 469

11 Reduction of the Ohmic Drop Operation in Single-pass High-conversion Mode Coplanar Interdigitated Microband Electrodes Plate and Channel Microreactors Reagent Flux and Applied Current Mass Transfer Limitations and Reagent Conversion Liquid-Solid Mass Transfer Coefficient and Coupling of the Electrode Processes Increase in the Space-Time Yield at a Constant Ohmic Penalty Experimental Investigations Reported in the Literature Reactor Model Conclusion and Outlook 477 References 479 Index 481