Inorganic Membrane Reactors
Fundamentals and Applications

Membrane reactors combine membrane functions such as separation, reactant distribution, and catalyst support with chemical reactions in a single unit. The benefits of this approach include enhanced conversion, increased yield, and selectivity, as well as a more compact and cost-effect design of reactor system. Hence, membrane reactors are an effective route toward chemical process intensification.

This book covers all types of porous membrane reactors, including ceramic, silica, carbon, zeolite, and dense metallic reactors such as Pd or Pd-alloy, oxygen ion-conducting, and proton-conducting ceramics. For each type of membrane reactor, the membrane transport principles, membrane fabrication, configuration and operation of membrane reactors, and their current and potential applications are described comprehensively. A summary of the critical issues and hurdles for each membrane reaction process is also provided, with the aim of encouraging successful commercial applications.

The audience for Inorganic Membrane Reactors includes advanced students, industrial and academic researchers, and engineers with an interest in membrane reactors.

1 Fundamentals of Membrane Reactors 1

1.1 Introduction 1

1.2 Membrane and Membrane Separation 1

1.2.1 Membrane Structure 2

1.2.2 Membrane Separation 4

1.2.3 Membrane Performance 6

1.3 Inorganic Membranes 7

1.3.1 Types of Inorganic Membranes 7

1.3.2 Fabrication of Inorganic Membranes 11

1.3.3 Characterization of Inorganic Membranes 13

1.3.4 Applications of Inorganic Membranes 13

1.4 Inorganic Membrane Reactors 14

1.4.1 Basic Principles of Membrane Reactors 14

1.4.2 Incorporation of Catalyst in Membrane Reactors 17

1.4.3 Configuration of Membrane Reactors 20

1.4.4 Classification of Membrane Reactors 23

References 25

2 Porous Membrane Reactors 27

2.1 Introduction 27

2.2 Gas Permeation in Porous Membranes 28

2.2.1 Types of Porous Membranes 28

2.2.2 Transport Mechanisms 30

2.2.3 Gas Permeation Flux through Porous Membranes 33

2.3 Preparation of Porous Membranes 38

2.3.1 Dip-Coating Method 39

2.3.2 Sol-Gel Method 41

2.3.3 Chemical Vapor Deposition Method 42

2.3.4 Phase Inversion Method 44

2.3.5 O ther Preparation Methods 46

2.4 Porous Membranes for Chemical Reactions 47

2.4.1 Membrane Materials 47

2.4.2 Membrane Functions 49

2.5 Catalysis in Porous Membrane Reactors 50

2.5.1 Catalyst in Membrane Reactors 50

2.5.2 Catalyst Deposition in Porous Membranes 52

2.6 O peration of Porous Membrane Reactors 53

2.6.1 Packed Bed Membrane Reactors 53

2.6.2 Catalytic Membrane Reactors 55

2.6.3 Coupling of Membrane Functions 57

2.6.4 Non-uniform Distribution of Membrane Permeability 57

2.7 Applications of Porous Membrane Reactors 59

2.7.1 Dehydrogenation Reactions 59

2.7.2 Reforming Reactions for Hydrogen Production 60

2.7.3 Partial Oxidation Reactions 62

2.7.4 Gas–Liquid–Solid Multiphase Reactions 65

2.7.5 O ther Reactions 66

2.8 Prospects and Challenges 67

Notation 68

References 70

3 Zeolite Membrane Reactors 75

3.1 Introduction 75

3.2 Permeation in Zeolite Membranes 76

3.2.1 Types of Zeolite Membranes 76

3.2.2 Transport Mechanisms 76

3.2.3 Permeation Flux in Zeolite Membranes 78

3.3 Preparation of Zeolite Membranes 80

3.3.1 In-Situ Crystallization Method 80

3.3.2 Secondary Growth Method 82

3.3.3 Vapor-Phase Transport Method 84

3.3.4 Microwave Synthesis Method 85

3.4 Configuration of Zeolite Membrane Reactors 86

3.4.1 Packed Bed Membrane Reactor 87

3.4.2 Catalytic Membrane Reactor 87

3.4.3 Pervaporation Membrane Reactor 88

3.4.4 Membrane Microreactor 89

3.5 Applications of Zeolite Membrane Reactors 90

3.5.1 Dehydrogenation Reactions 90

3.5.2 Dehydration Reactions 90

3.5.3 Oxidative Reactions 93

3.5.4 Isomerization Reactions 94

3.6 Prospects and Challenges 94

Notation 96

References 97

4 Dense Metallic Membrane Reactors 101

4.1 Introduction 101

4.2 Gas Permeation in Dense Metallic Membranes 102

4.2.1 Types of Dense Metallic Membranes 102

4.2.2 Hydrogen Permeation Mechanism in Pd-Based Membranes 103

4.2.3 Effect of Substrate on H2 Permeation 108

4.3 Preparation of Dense Metallic Membranes 110

4.3.1 Cold-Rolling and Diffusion Welding Method 110

4.3.2 Electroless Plating Method 111

4.3.3 Electroplating Method 113

4.3.4 Chemical Vapor Deposition Method 114

4.3.5 High-Velocity Oxy-Fuel Spraying Method 115

4.3.6 Magnetron Sputtering Method 115

4.3.7 Summary 115

4.4 Configurations of Metallic Membrane Reactors 117

4.4.1 Packed Bed Membrane Reactor 117

4.4.2 Membrane Microreactor 122

4.5 Applications of Dense Metallic Membrane Reactors 123

4.5.1 Dehydrogenation Reactions 123

4.5.2 Reforming Reactions for H2 Production 126

4.5.3 Direct Hydroxylation of Aromatic Compounds 133

4.5.4 Direct Synthesis of Hydrogen Peroxide 134

4.6 Challenges and Prospects 135

Notation 136

References 137

5 Dense Ceramic Oxygen-Permeable Membrane Reactors 143

5.1 Introduction 143

5.2 Oxygen Permeation in Dense Ceramic Membranes 146

5.2.1 Membrane Materials 146

5.2.2 O xygen Permeation Flux in MIEC Membranes 148

5.3 Preparation of Dense Ceramic Membranes 154

5.3.1 Isostatic Pressing 154

5.3.2 Extrusion 154

5.3.3 Phase Inversion 155

5.3.4 Slurry Coating 156

5.3.5 Tape Casting 156

5.4 Dense Ceramic Membrane Reactors 157

5.4.1 Principles of Dense Ceramic Membrane Reactors 157

5.4.2 Configurations of Dense Ceramic Membrane Reactors 159

5.5 Applications of Dense Ceramic Oxygen Permeable Membrane Reactors 160

5.5.1 Partial Oxidation of Methane to Syngas 161

5.5.2 Oxidative Coupling of Methane 165

5.5.3 Oxidative Dehydrogenation of Alkanes (Ethane and Propane) 169

5.5.4 Decomposition of H2O, NO x, and CO2 170

5.6 Prospects and Challenges 176

Notation 178

References 179

6 Proton-Conducting Ceramic Membrane Reactors 187

6.1 Introduction 187

6.2 Proton/Hydrogen Permeation in

Proton-Conducting Ceramic Membranes 187

6.2.1 Proton-Conducting Ceramics 187

6.2.2 Hydrogen/Proton Permeation in Mixed Conducting Membranes 189

6.3 Preparation of Proton-Conducting Ceramic Membranes 193

6.3.1 Suspension Coating 193

6.4 Configuration of Proton-Conducting Membrane Reactors 195

6.5 Applications of Proton-Conducting Ceramic Membrane Reactors 198

6.5.1 Dehydrogenation Coupling of Methane 199

6.5.2 Dehydrogenation of Alkanes into Alkenes 201

6.5.3 WGS Reaction and Water Electrolysis for Hydrogen Production 203

6.5.4 Decomposition of NOx 205

6.5.5 Synthesis of Ammonia 206

6.5.6 Challenges and Future Work 208

Notation 210

References 210

7 Fluidized Bed Membrane Reactors 215

7.1 Introduction 215

7.2 Configurations and Construction of FBMRs 216

7.3 Applications 222

7.3.1 Methane Steam Reforming and Dehydrogenation Reactions 222

7.3.2 Partial Oxidation Reactions 224

7.4 Prospects and Challenges 224

References 225

8 Membrane Microreactors 227

8.1 Introduction 227

8.2 Configurations and Fabrication of Membrane Microreactors 228

8.2.1 Plate-Type Membrane Microreactors 228

8.2.2 Tubular Membrane Microreactors 233

8.3 Applications of Membrane Microreactors 238

8.3.1 Pd-MMRs for Hydrogenation/Dehydrogenation Reactions 238

8.3.2 Zeolite-MMRs for Knoevenagel Condensation and Selective Oxidation Reactions 241

8.3.3 Catalytic MMRs for G–L–S Reactions 243

8.4 Fluid Flow in Membrane Microreactors 244

8.5 Prospects and Challenges 246

References 247

9 Design of Membrane Reactors 251

9.1 Introduction 251

9.2 Design Equations for Membrane Reactors 251

9.2.1 Packed Bed Membrane Reactors 252

9.3 Flow-Through Catalytic Membrane Reactors 259

9.3.1 Fluidized Bed Membrane Reactors 261

9.4 Modeling Applications 264

9.4.1 Oxidative Dehydrogenation of n-Butane in a Porous Membrane Reactor 264

9.4.2 Coupled Dehydrogenation and Hydrogenation Reactions in a Pd/Ag Membrane Reactor 265

9.4.3 POM in a Dense Ceramic Oxygen-Permeable Membrane Reactor 268

9.5 Concluding Remarks 274

Notation 275

References 277

Index 279

Xiaoyao Tan is Professor of Chemical Engineering at Tianjin Polytechnic University, China Currently he teaches Membrane Science and Technology to undergraduate students. He received his PhD from Dalian Institute of Chemical Physics, Chinese Academy of Sciences in 1995, and has been working in the membrane area for more than 15 years. His research interests involve the preparation and characterization of various inorganic membranes such as ceramics, metals, and zeolites for fluid separations/reactions. He has published 120+ research papers in international referred journals, 15 patents and 4 book chapters in the area of inorganic membranes and membrane reactors.

Kang Li is Professor of Chemical Engineering at Imperial College London. His present research interests are in the preparation and characterisation of polymeric and inorganic hollow fibre membranes, fluid separations using membranes, and membrane reactors for energy application and CO2 capture. Kang Li currently leads a research group at Imperial of 2 MSc students, 8 PhD students and 3 post-doctorial research fellows. He has published over 180 research papers in international referred journals, holds five patents, and is the author of a book in the area of ceramic membranes (Ceramic Membranes for Separation and Reaction, John Wiley, 2007).