Preface ..................................................... XI
List of Contributors ...................................... XIII
1 Dense Ceramic Membranes for Hydrogen Separation .............. 1
Truls Norby and Reidar Haugsrud
1.1 Introduction ............................................ 1
1.2 Applications and Principles of Operation ................ 2
1.2.1 Simple Cases ..................................... 2
1.2.2 Examples of More Complex Applications ............ 4
1.3 Defect Chemistry of Dense Hydrogen-permeable Ceramics ... 5
1.3.1 Materials Classes ................................ 5
1.3.2 Neutral and Ionized Hydrogen Species in Oxides ... 6
1.3.4 Protonic Defects and Their Transport ............. 7
1.3.5 Defect Structures of Proton-conducting Oxides .... 8
1.3.6 Diffusivity, Mobility and Conductivity The
Nernst-Einstein Relation ........................ 10
1.4 Wagner Transport Theory for Dense Ceramic Hydrogen-
Separation Membranes ................................... 11
1.4.1 General Expressions ............................. 11
1.4.2 From Charged to Well-Defined Species: The
Electrochemical Equilibrium ..................... 12
1.4.3 The Voltage Over a Sample ....................... 12
1.4.4 Flux of a Particular Species .................... 13
1.4.5 Fluxes in a Mixed Proton, Oxygen Ion, and
Electron Conductor .............................. 14
1.4.6 Fluxes in a Mixed Proton and Electron
Conductor ....................................... 15
1.4.7 Fluxes in a Mixed Proton and Oxygen Ion
Conductor ....................................... 18
1.4.8 Fluxes in a Mixed Proton, Oxygen Ion, and
Electron Conductor Revisited .................... 19
1.4.9 Permeation of Neutral Hydrogen Species .......... 19
1.4.10 What About Hydride Ions? ........................ 21
1.5 Surface Kinetics of Hydrogen Permeation in Mixed
Proton-Electron Conductors ............................. 21
1.6 Issues Regarding Metal Cation Transport in Hydrogen-
permeable Membrane Materials ........................... 24
1.7 Modeling Approaches .................................... 24
1.8 Experimental Techniques and Challenges ................. 26
1.8.1 Investigation of Fundamental Materials
Properties ...................................... 26
1.8.1.1 Concentration .......................... 26
1.8.1.2 Diffusion .............................. 27
1.8.1.3 Conductivity ........................... 27
1.8.1.4 Transport Numbers ...................... 29
1.8.1.5 Other Properties ....................... 30
1.8.2 Investigation of Surface Kinetics ............... 31
1.8.3 Measurements and Interpretation of Hydrogen
Permeation ...................................... 34
1.9 Hydrogen Permeation in Selected Systems ................ 35
1.9.1 A Few Words on Flux and Permeability ............ 35
1.9.2 Classes of Membranes ............................ 36
1.9.3 Mixed Proton-Electron Conducting Oxides ......... 36
1.9.4 Cermets ......................................... 42
1.9.5 Permeation in Other Oxide Classes and the
Possibility of Neutral Hydrogen Species ......... 43
1.9.6 Comparison with Metals .......................... 44
1.10 Summary ................................................ 45
2 Ceramic Proton Conductors ................................... 49
Vineet K. Gupta and Jerry Y.S. Lin
2.1 Introduction ........................................... 49
2.2 General Properties of Perovskite-structured
Proton-conducting Ceramic Membranes .................... 51
2.2.1 Creation of Protonic Carriers ................... 51
2.2.2 Transport Properties ............................ 52
2.2.3 Electronic Conductivity and Its Improvement ..... 57
2.3 Synthesis of Proton-conducting Ceramic Membranes ....... 58
2.3.1 Synthesis of Powders ............................ 58
2.3.2 Effect of Synthesis Conditions on Membrane
Performance ..................................... 59
2.3.3 Preparation of Thin Films ....................... 60
2.4 Hydrogen Permeation .................................... 61
2.4.1 The H2 Permeation Set-up and Sealing System ..... 61
2.4.2 Effects of Process Variables on H2 Flux ......... 63
2.4.2.1 Effect of Feed and Sweep Side Gas
Concentrations ......................... 63
2.4.2.2 Effect of Membrane Thickness ........... 64
2.4.2.3 Effect of Temperature .................. 65
2.4.3 Mathematical Models for Hydrogen Permeation ..... 66
2.5 Chemical Stability of Protonic Conductors .............. 68
2.5.1 Stability in CO2 Atmospheres .................... 68
2.5.2 Stability in Moisture-containing Atmospheres .... 71
2.5.3 Stability in Reducing Atmospheres ............... 71
2.6 Future Directions and Perspectives ..................... 72
3 Palladium Membranes ......................................... 77
Stephen N. Paglieri
3.1 Introduction ........................................... 77
3.2 History and Applications ............................... 78
3.3 Effect of Impurities ................................... 79
3.4 Palladium Alloy Membranes .............................. 81
3.5 Palladium Deposition Methods ........................... 82
3.6 Membrane Characterization and Analysis ................. 84
3.7 Palladium Composite Membranes .......................... 87
3.8 Recent Advances ........................................ 89
3.9 Summary and Outlook .................................... 93
4 Superpermeable Hydrogen Transport Membranes ................ 107
Michael V. Mundschau, Xiaobing Xie, and Carl R. Evenson IV
4.1 Introduction .......................................... 107
4.2 Theoretical Limits of Superpermeable Membranes ........ 109
4.3 Superpermeable Membranes in Plasma Physics ............ 111
4.4 Hydrogen Transport Membranes in Nuclear Reactor
Cooling Systems ....................................... 112
4.5 Hydrogen Transport Membranes in the Chemical
Industry .............................................. 114
4.6 Membrane Hydrogen Dissociation Catalysts and
Protective Layers ..................................... 116
4.7 Thermal and Chemical Expansion ........................ 119
4.8 Methods of Catalyst Application ....................... 121
4.9 Catalyst Tolerance to Sulfur .......................... 124
4.10 Interdiffusion ........................................ 125
4.11 Measured Hydrogen Permeability of Bulk Membrane
Materials ............................................. 126
4.12 Conclusions ........................................... 136
5 Engineering Scale-up for Hydrogen Transport Membranes ...... 139
David J. Edlund
5.1 Historical Review ..................................... 140
5.2 General Review of Hydrogen-permeable Metal Membranes
and Module Design ..................................... 141
5.2.1 Scale-up and Differential Expansion ............ 142
5.2.2 Overview of Sealing Methods .................... 146
5.3 Scale-up from Laboratory Test-and-Evaluation Module
to Commercial Membrane Module ......................... 147
5.3.1 Cost and Membrane Thickness .................... 149
5.3.2 Module Maintenance and Operating Costs ......... 152
5.3.3 Overview of Membrane Fabrication Methods ....... 152
5.4 Membrane Module Design and Construction ............... 153
5.4.1 Design of the Module Shell ..................... 159
5.4.2 Membrane Sealing Options ....................... 160
5.4.3 Commercial Applicability ....................... 163
6 The Evolution of Materials and Architecture for Oxygen
Transport Membranes ........................................ 165
John Sirman
6.1 Introduction .......................................... 165
6.2 Oxygen Separation and Collection ...................... 165
6.2.1 Background for Selection of Materials for
Oxygen Separation and Collection ............... 166
6.2.2 Membrane Materials Concepts .................... 168
6.2.3 Membrane Architecture Concepts ................. 174
6.2.4 Summary of Oxygen Separation Materials and
Architecture ................................... 180
6.3 Syngas Production and Combustion Applications ......... 180
6.3.1 Background for Selection of Materials for
Syngas Production and Combustion
Applications ................................... 180
6.3.2 Membrane Materials Concepts .................... 182
6.3.3 Membrane Architecture Concepts ................. 183
6.3.4 Summary of Syngas and Combustion Applications
Materials and Architecture ..................... 184
7 Membranes for Promoting Partial Oxidation Chemistries ...... 185
Anthony F. Sammells, James H. White, and Richard Mackay
7.1 Introduction .......................................... 185
7.2 On the Nature of Perovskite-related Metal Oxides for
Achieving Mixed Oxygen Anion and Electron
Conduction ............................................ 188
7.2.1 Background ..................................... 188
7.2.2 Early Work towards the Selection of Mixed
Conductors ..................................... 189
7.2.3 Requirements for Oxygen Anion and Electronic
Conduction within Perovskites .................. 189
7.2.4 Empirical Factors Relating to Oxygen Anion
Transport in Perovskite-related Membranes ...... 191
7.2.5 Introducing Electronic Conductivity into
a Perovskite-related Lattice ................... 192
7.3 The Application of Oxygen Transport Membranes to
Partial Oxidation Chemistries ......................... 193
7.3.1 Natural Gas Conversion to Synthesis Gas -
General Considerations ......................... 193
7.3.2 Methane Partial Oxidation to Synthesis Gas in
Membrane Reactors .............................. 196
7.3.3 Liquid Fuel Reforming .......................... 198
7.3.4 Coal/Biomass to Synthesis Gas .................. 200
7.3.5 Oxygen Reduction Catalysis Requirements in
Oxygen Transport Membranes ..................... 202
7.3.6 Methane to Ethylene ............................ 203
7.3.7 Catalysis Considerations for Promoting
Methane Coupling Reactions ..................... 204
7.3.8 Catalyst Implementation on Dense Oxygen
Transport Media for Oxidative Coupling ......... 206
7.3.9 Alkane Dehydrogenation ......................... 206
7.3.10 Hydrogen Sulfide Partial Oxidation ............. 207
7.3.11 Some Thoughts on the Potential Contribution
of Membrane Technology towards Realizing
a Hydrogen Economy ............................. 209
8 Syngas Membrane Engineering Design and Scale-Up Issues.
Application of Ceramic Oxygen Conducting Membranes ......... 215
Michael Carolan
8.1 Membrane Design and Engineering ....................... 216
8.2 Reactor Design and Engineering ........................ 227
8.3 Planar Membrane Reactors .............................. 232
8.4 Ceramic-to-Ceramic Seals .............................. 235
8.5 Ceramic-to-Metal Seals ................................ 238
8.6 Summary and Conclusions ............................... 241
9 Economics Associated with Implementation of Membrane
Reactors ................................................... 245
Alessandra Criscuoli
9.1 Introduction .......................................... 245
9.2 Membrane Reactors ..................................... 246
9.3 Factors Influencing the Economics ..................... 249
9.4 Dense Membrane Reactors for the Water-Gas Shift
Reaction .............................................. 251
9.5 Economic Feasibility of Water-Gas Shift Pd-based
Membrane Reactors ..................................... 256
9.6 Future Directions ..................................... 261
Index ...................................................... 265
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