Microreactors: New Technology for Modern Chemistry (2000)

1 State of the Art of Microreaction Technology 1.1 Definition 1.1.1 Microsystems Termed Microreactor 1.1.2 Structural Hierarchy of Microreactors 1.1.3 Functional Classification of Microreactors 1.1.4 Dividing Line Between Analysis and Reaction Systems 1.2 Fundamental Advantages of Microreactors 1.2.1 Fundamental Advantages of Miniaturized Analysis Systems 1.2.2 Fundamental Advantages of Nano-Scale Reactors 1.2.3 Advantages of Microreactors Due to Decrease of Physical Size 1.2.4 Advantages of Microreactors Due to Increase of Number of Units 1.3 Potential Benefits of Microreactors Regarding Applications 1.4 References 2 Modern Microfabrication Techniques for Microreactors 2.1 Microfabrication Techniques Suitable for Microreactor Realization 2.2 Evaluation of Suitability of a Technique 2.3 Anisotropic Wet Etching of Silicon 2.4 Dry Etching of Silicon 2.5 LIGA Process 2.6 Injection Molding 2.7 Wet Chemical Etching of Glass 2.8 Advanced Mechanical Techniques 2.8.1 Surface Cutting with Diamond Tools 2.8.2 Milling, Turning and Drilling 2.8.3 Punching 2.8.4 Embossing 2.9 Isotropic Wet Chemical Etching of Metal Foils 2.10 Electro Discharge Machining (EDM) of Conductive Materials 2.10.1 Wire-Cut Erosion and Die Sinking 2.10.2 -EDM Drilling 2.11 Laser Micromachining 2.12 Interconnection Techniques 2.12.1 Microlamination of Thin Metal Sheets 2.13 Functional Coatings 2.13.1 Functional Coatings for Corrosion Prevention 2.13.2 Functional Coatings for Fouling Prevention 2.14 References 3 Micromixers 3.1 Mixing Principles and Classes of Macroscopic Mixing Equipment 3.2 Mixing Principles and Classes of Miniaturized Mixers 3.3 Potential of Miniaturized Mixers 3.4 Contacting of Two Substreams, e.g. in a Mixing Tee Configuration 3.4.1 Mixing Tee-Type Configuration 3.4.2 Double Mixing Tee-Type Configuration 3.5 Collision of High-Energy Substreams for Spraying/Atomizing 3.5.1 Collision of Three Substreams in a Microjet Reactor 3.6 Injection of Many Small Substreams of One Component into a Main Stream of Another Component 3.6.1 Injection of Multiple Microjets 3.7 Manifold Splitting and Recombination of a Stream Consisting of Two Fluid Lamellae of Both Components 3.7.1 Multiple Flow Splitting and Recombination Combined with Channel Reshaping 3.7.2 Multiple Flow Splitting and Recombination Using Fork-Like Elements 3.7.3 Multiple Flow Splitting and Recombination Using a Separation Plate 3.7.4 Multiple Flow Splitting and Recombination Using a Ramp-Like Channel Architecture 3.8 Injection of Many Substreams of Both Components 3.8.1 Multilamination of Fluid Layers in an Interdigital Channel Configuration 3.8.2 Vertical Multilamination of Fluid Layers Using a V-type Nozzle Array 3.8.3 Multilamination Using a Stack of Platelets with Microchannels 3.8.4 Multilamination Using a Stack of Platelets with Star-Shaped Openings 3.9 Decrease of Diffusion Path Perpendicular to the Flow Direction by Increase of Flow Velocity 3.9.1 Decrease of Layer Thickness by Hydrodynamic Focusing 3.10 Externally Forced Mass Transport, e.g. by Stirring. Ultrasonic Wave, Electrical and Thermal Energy 3.10.1 Dynamic Micromixer Using Magnetic Beads 3.11 References 4 Micro Heat Exchangers 4.1 Micro Heat Exchangers with Wide and Flat Channels 4.1.1 Cross-Flow Heat Exchange in Stacked Plate Devices 4.1.2 Cross-Flow Heat Exchange Based on Cross-Mixing 4.1.3 Counter-Flow Heat Exchange in Stacked Plate Devices 4.1.4 Electrically Heated Stacked Plate Devices 4.2 Micro Heat Exchangers with Narrow and Deep Channels 4.2.1 Heat Exchanger with One-Sided Structured Channels 4.2.2 Heat Exchanger with Double-Sided Structured Channels 4.3 Micro Heat Exchangers with Breakthrough Channels 4.4 Axial Heat Conduction 4.4.1 Numerical Calculations of the Influence of Material on Heat Transfer Efficiency 4.4.2 The Use of Thermal Blocking Structures 4.5 Permanent Generation of Entrance Flow by Fins 4.6 Generation of a Periodic Flow Profile by Sine-Wave Microchannels 4.7 Microtechnology-Based Chemical Heat Pumps 4.8 Performance Characterization of Micro Heat Exchangers 4.8.1 Temperature Profiles of Micro Heat Exchangers Yielded by Thermograms of Infrared Cameras 4.9 References 5 Microseparation Systems and Specific Analytical Modules for Microreactors 5.1 Microextractors 5.1.1 Partially Overlapping Channels 5.1.2 Wedge-Shaped Flow Contactor 5.1.3 Contactor Microchannels Separated by a Micromachined Membrane 5.1.4 Contactor Microchannels Separated by Sieve-Like Walls 5.1.5 Micromixer - Settler Systems 5.2 Microfilters 5.2.1 Isoporous-Sieve Microfilters 5.2.2 Cross-Flow Microfilters 5.3 Gas Purification Microsystems 5.4 Gas Separation Microdevices 5.5 Specific Analytical Modules for Microreactors 5.5.1 Analytical Modules for In-Line IR Spectroscopy 5.5.2 Analytical Module for Fast Gas Chromatography 5.6 References 6 Microsystems for Liquid Phase Reactions 6.1 Types of Liquid Phase Microreactors 6.2 Liquid/Liquid Synthesis of a Vitamin Precursor in a Combined Mixer and Heat Exchanger Device 6.3 Acrylate Polymerization in Micromixers 6.4 Ketone Reduction Using a Grignard Reagent in Micromixers 6.5 Laboratory-Scale Organic Chemistry in Micromixer/Tube Reactors 6.6 Dushman Reaction Using Hydrodynamic Focusing Micromixers and High-Aspect Ratio Heat Exchangers 6.7 Synthesis of Microcrystallites in a Microtechnology-Based Continuous Segmented-Flow Tubular Reactor 6.8 Electrochemical Microreactors 6.8.1 Synthesis of 4-Methoxybenzaldehyde in a Plate-to-Plate Electrode Configuration 6.8.2 Scouting Potentiodynamic Operation of Closed Microcells 6.9 References 7 Microsystems for Gas Phase Reactions 7.1 Catalyst Supply for Microreactors 7.2 Types of Gas Phase Microreactors 7.3 Microchannel Catalyst Structures 7.3.1 Flow Distribution in Microchannel Catalyst Reactors 7.3.2 Partial Oxidation of Propene to Acrolein 7.3.3 Selective Partial Hydrogenation of a Cyclic Triene 7.3.4 H 2 /O 2 Reaction 7.3.5 Selective Partial Hydrogenation of Benzene 7.3.6 Selective Oxidation of 1-Butene to Maleic Anhydride 7.3.7 Selective Oxidation of Ethylene to Ethylene Oxide 7.3.8 Reactions Utilizing Periodic Operation 7.4 Microsystems with Integrated Catalyst Structures and Heat Exchanger 7.4.1 Oxidative Dehydrogenation of Alcohols 7.4.2 Synthesis of Methyl Isocyanate and Various Other Hazardous Gases 7.4.3 H 2 /O 2 Reaction in the Explosion Regime 7.5 Microsystems with Integrated Catalyst Structures and Mixer 7.5.1 Synthesis of Ethylene Oxide 7.6 Microsystems with Integrated Catalyst Structures. Heat Exchanger and Sensors 7.6.1 Oxidation of Ammonia 7.6.2 H 2 /O 2 Reaction 7.7 Microsystems with Integrated Mixer, Heat Exchanger, Catalyst Structures and Sensors 7.7.1 HCN Synthesis via the Andrussov Process 7.8 References 8 Gas/Liquid Microreactors 8.1 Gas/Liquid Contacting Principles and Classes of Miniaturized Contacting Equipment 8.2 Contacting of Two Gas and Liquid Substreams in a Mixing Tee Configuration 8.2.1 Injection of One Gas and Liquid Substream 8.2.2 Injection of Many Gas and Liquid Substreams into One Common Channel 8.2.3 Injection of Many Gas and Liquid Substreams into One Packed Channel 8.2.4 Injection of Many Gas Substreams into One Liquid Channel with Catalytic Walls 8.2.5 Injection of Many Gas and Liquid Substreams into Multiple Channels 8.3 Generation of Thin Films in a Falling Film Microreactor 8.4 References 9 Microsystems for Energy Generation 9.1 Microdevices for Vaporization of Liquid Fuels 9.2 Microdevices for Conversion of Gaseous Fuels to Syngas by Means of Partial Oxidations 9.2.1 Hydrogen Generation by Partial Oxidations 9.2.2 Partial Oxidation of Methane in a Stacked Stainless Steel Sheet System 9.2.3 Partial Oxidation of Methane in a Microchannel Reactor 9.3 Microdevices for Conversion of Gaseous Fuels to Syngas by Means of Steam Reforming 9.3.1 Steam Reforming of Methanol in Microstructured Platelets 9.4 References 10 Microsystems for Catalyst and Material Screening 10.1 Parallel Screening of Heterogeneous Catalysts in a Microchannel Reactor 10.2 Parallel Screening of Heterogeneous Catalysts in Conventional Mini-Scale Reactors 10.3 References 11 Methodology for Distributed Production 11.1 The Miniplant Concept 11.1.1 Miniplant Concept for HCN Manufacture 11.1.2 The Disposable Batch Miniplant 11.2 Paradigm Change in Large-Scale Reactor Design Towards Operability and Environmental Aspects Using Miniplants 11.3 References Index