Membrane Reactors: Distributing Reactants to Improve Selectivity and Yield

Membrane Reactors: Distributing Reactants to Improve Selectivity and Yield......Page 1
Contents......Page 7
Preface......Page 13
List of Contributors......Page 17
1.1 Challenges in Chemical Reaction Engineering......Page 21
1.2 Concepts of Membrane Reactors......Page 23
1.3 Available Membranes......Page 26
1.4 Illustration of the Selectivity Problem......Page 28
1.5.1 Reaction Rates......Page 29
1.5.3 Mass Balance of a Plug Flow Tubular Reactor......Page 30
1.5.4 Selectivity and Yield......Page 32
1.6 Distributed Dosing in Packed-Bed and Membrane Reactors......Page 33
1.6.1 Adjusting Local Concentrations to Enhance Selectivities......Page 35
1.6.2 Optimization of Dosing Profiles......Page 36
1.7 Kinetic Compatibility in Membrane Reactors......Page 41
1.8 Current Status of Membrane Reactors of the Distributor Type......Page 42
Superscripts and Subscripts......Page 43
References......Page 44
2.2 Momentum, Mass and Heat Balances......Page 49
2.3.1.2 Heat Conduction......Page 55
2.3.1.3 Molecular Diffusion......Page 56
2.3.2 Porous Domains......Page 58
2.3.2.2 K nudsen Diffusion......Page 59
2.3.2.4 Models for Description of Gas Phase Transport in Porous Media......Page 60
2.4 Reduced Models......Page 62
2.5 Solvability, Discretization Methods and Fast Solution......Page 64
2.6.1 Application of FLUENT......Page 69
2.6.2 Application of MooNMD......Page 70
2.6.3 Application of ProM oT......Page 71
Latin Notation......Page 76
Greek Notation......Page 77
Super- and Subscripts......Page 78
References......Page 79
3.1 Introduction......Page 83
3.2 The Reaction Network of the Oxidative Dehydrogenation of Ethane......Page 85
3.3 Catalysts and Structure–Activity Relations......Page 86
3.3.1 Catalyst Preparation and Characterization......Page 89
3.3.2 Mechanistic Aspects: Correlation Between Structure and Activity......Page 91
3.4 Derivation of a Kinetic Model......Page 93
3.4.1.2 Set-Up......Page 94
3.4.1.3 Procedures......Page 95
3.4.2.1 Overall Catalyst Performance......Page 96
3.4.2.2 Evaluation of Intraparticle Mass Transfer Limitations......Page 97
3.4.3.2 Kinetic Models......Page 98
3.4.4 Suggested Simplified Model......Page 99
References......Page 102
4.1 Introduction......Page 105
4.2 Aspects of Discretizing Convection-Diffusion Equations......Page 107
4.3 Velocity Fields in Membrane Reactors......Page 109
4.4.1.1 Task and Tools......Page 117
4.4.1.2 Identification by Single Gas Permeation......Page 120
4.4.1.3 Validation by Isobaric Diffusion and by Transient Diffusion......Page 125
4.4.2.1 Diagnosis......Page 127
4.4.2.2 Identification......Page 130
4.4.2.3 Validation......Page 131
4.4.3 Mass Transport in 2 - D Models......Page 134
4.5 Analysis of Convective and Diffusive Transport Phenomena in a CMR......Page 135
4.6 Parametric Study of a CMR......Page 140
4.6.1 Influence of Characteristic Geometrical Parameters......Page 143
4.6.2 Influence of the Morphological Membrane Parameters in the Catalyst Layer......Page 144
4.6.3 Influence of the Operating Conditions......Page 147
References......Page 150
5.1 Introduction......Page 153
5.2.1 Reactant Dosing in a Packed-Bed Membrane Reactor Cascade......Page 154
5.2.2.1 Simplified 1-D Model......Page 156
5.2.2.2 More Detailed 1+1-D Model......Page 157
5.2.2.3 Detailed 2-D Modeling of a Single-Stage PBMR......Page 159
5.3.1 Model Reactions......Page 160
5.3.2 Simulation Study for ODH of Ethane Using the 1-D Model......Page 161
5.4.2 Single-Stage Packed-Bed Membrane Reactor in a Pilot-Scale......Page 165
5.4.5 Analytics......Page 167
5.5.1 Comparison Between PBR and PBMR Using Ceramic Membranes in a Single - Stage Operation Mode......Page 168
5.5.2 2-D Simulation Results–Comparison Between PBR and PBMR......Page 172
5.5.3 Application of Sintered Metal Membranes for the ODH of Ethane......Page 173
5.5.4 Investigation of a Membrane Reactor Cascade–Impact of Dosing Profiles......Page 175
5.5.5 Quantitative Comparison of the Investigated Reactor Configurations......Page 177
5.6.1 Comparison Between PBR and a Single-Stage PBMR Using Ceramic Membranes......Page 178
5.6.2 Investigation of a Three-Stage Membrane Reactor Cascade......Page 179
5.7 Summary and Conclusions......Page 180
Latin Notation......Page 181
References......Page 182
6.1 Introduction......Page 187
6.2.1 Theory......Page 190
6.2.2.1 Bubble Size......Page 193
6.2.2.2 Secondary Gas Distribution......Page 195
6.2.3 Comparison Between Co-Feed and Distributed Oxygen Dosage......Page 196
6.3.1 Experimental Set-Up......Page 198
6.3.2 Experimental Procedure......Page 200
6.3.4 Influence of the Oxygen Concentration......Page 201
6.3.5 Influence of the Temperature......Page 203
6.3.6 Influence of the Superficial Gas Velocity......Page 204
6.3.7 Influence of the Secondary to Primary Gas Flow Ratio......Page 205
6.3.8 Influence of Distributed Reactant Dosing with Oxygen in the Primary Gas Flow......Page 207
6.4 Conclusions......Page 208
Latin Notation......Page 209
References......Page 210
7.1 Introduction......Page 213
7.2.1 Classification of Membranes......Page 214
7.2.2 Ion Conductivity of Selected Materials......Page 215
7.2.3 Membrane–Electrode–Interface Design in Solid Electrolyte Membrane Reactor......Page 216
7.2.4 Operating Modi of Solid Electrolyte Membrane Reactors......Page 218
7.2.5 Cell Voltage Analysis......Page 219
7.2.6 Non-Faradaic Effects......Page 220
7.3 Modeling of Solid Electrolyte Membrane Reactors......Page 221
7.3.1 Reactor Model for Systems Containing Solid Electrolyte Membranes......Page 222
7.3.3 Parameters for Charge Transfer and Solid Electrolyte Conductivity......Page 226
7.3.4 Analysis of Maleic Anhydride Synthesis in Solid Electrolyte Membrane Reactor......Page 229
7.3.5 Analysis of Oxidative Dehydrogenation of Ethane in a Solid Electrolyte Packed-Bed Membrane Reactor......Page 232
7.4.1.1 Solid Oxide Fuel Cell for Electrical Energy Production......Page 236
7.4.1.2 Oxidative Coupling of Methane to C2 and Syngas from Methane......Page 237
7.4.1.3 Dry Reforming of Methane......Page 238
7.4.2 High-Temperature Proton Conductors......Page 239
7.4.2.1 Hydrogen Sensors and Pumps......Page 240
7.4.2.3 Electrocatalytic Membrane Reactors......Page 241
7.4.3 Low-Temperature Proton Conductors......Page 242
7.4.3.1 PEM Fuel Cells......Page 243
7.4.3.2 Proton Exchange Membrane Reactors......Page 244
Latin Notation......Page 248
Characteristic Dimensionless Numbers......Page 249
References......Page 250
8.2.1 Reference Model......Page 255
8.2.2.1 Nonreactive Membrane Separation......Page 257
8.2.2.2 Membrane Reactor......Page 260
8.2.3.1 Formation of Traveling Waves......Page 265
8.2.3.2 Formation of Discontinuous Patterns......Page 266
8.3 Pattern Formation......Page 268
8.3.1 Analysis of a Simple Membrane Reactor Model......Page 269
8.3.1.1 Analysis of Steady-State Reactor Behavior for Vanishing Heat Dispersion......Page 272
8.3.1.2 Influence of Heat Dispersion......Page 274
8.3.2 Detailed Membrane Reactor Model......Page 275
8.3.2.1 Main Model Assumptions......Page 276
8.3.2.2 Model Equations of the Membrane......Page 277
8.4 Conclusions......Page 279
References......Page 281
9.1 General Aspects Regarding Membrane Reactors of the Distributor Type......Page 283
9.2 Oxidative Dehydrogenation of Ethane in Different Types of Membrane Reactors......Page 284
9.2.2 Fluidized-Bed Membrane Reactor......Page 285
9.3 General Conclusions......Page 286
Reference......Page 287
Index......Page 289