Fuel Cell Systems Explained

Cover......Page 1
Fuel Cell Systems Explained,\rSecond Edition......Page 2
ISBN-13: 9780470848579......Page 3
Preface......Page 16
Foreword to the First Edition......Page 6
Acknowledgements......Page 8
Abbreviations......Page 10
Symbols......Page 24
Table of Contents......Page 26
1.1 Hydrogen Fuel Cells - Basic Principles......Page 35
1.2 What Limits the Current?......Page 39
1.3 Connecting Cells in Series - the Bipolar Plate......Page 40
1.4 Gas Supply and Cooling......Page 44
1.5 Fuel Cell Types......Page 48
1.6 Other Cells - Some Fuel Cells, Some Not......Page 50
1.6.2 Metal/Air Cells......Page 51
1.6.3 Redox Flow Cells or Regenerative Fuel Cells......Page 52
1.7 Other Parts of a Fuel Cell System......Page 53
1.8 Figures Used to Compare Systems......Page 55
1.9 Advantages and Applications......Page 56
References......Page 58
2.1 Energy and the EMF of the Hydrogen Fuel Cell......Page 59
2.2 The Open Circuit Voltage of Other Fuel Cells and Batteries......Page 64
2.3 Efficiency and Efficiency Limits......Page 65
2.4 Efficiency and the Fuel Cell Voltage......Page 68
2.5.1 The Nernst Equation......Page 69
2.5.2 Hydrogen Partial Pressure......Page 72
2.5.3 Fuel and Oxidant Utilization......Page 73
2.5.4 System Pressure......Page 74
2.5.5 An Application - Blood Alcohol Measurement......Page 75
2.6 Summary......Page 76
References......Page 77
3.1 Introduction......Page 78
3.3 Fuel Cell Irreversibilities - Causes of Voltage Drop......Page 80
3.4.1 The Tafel Equation......Page 81
3.4.2 The Constants in the Tafel Equation......Page 82
3.4.3 Reducing the Activation Overvoltage......Page 85
3.5 Fuel Crossover and Internal Currents......Page 86
3.6 Ohmic Losses......Page 89
3.7 Mass Transport or Concentration Losses......Page 90
3.8 Combining the Irreversibilities......Page 92
3.9 The Charge Double Layer......Page 94
3.10 Distinguishing the Different Irreversibilities......Page 96
References......Page 99
4.1 Overview......Page 100
4.2 How the Polymer Electrolyte Works......Page 102
4.3 Electrodes and Electrode Structure......Page 105
4.4.1 Overview of the Problem......Page 108
4.4.2 Airflow and Water Evaporation......Page 109
4.4.3 Humidity of PEMFC Air......Page 113
4.4.4 Running PEM Fuel Cells without Extra Humidification......Page 116
4.4.5 External Humidification - Principles......Page 118
4.4.6 External Humidification - Methods......Page 120
4.5.1 Cooling Using the Cathode Air Supply......Page 123
4.5.2 Separate Reactant and Cooling Air......Page 124
4.5.3 Water Cooling of PEM Fuel Cells......Page 126
4.6.2 Flow Field Patterns on the Bipolar Plates......Page 127
4.6.3 Making Bipolar Plates for PEM Fuel Cells......Page 129
4.6.4 Other Topologies......Page 133
4.7.1 Outline of the Problem......Page 135
4.7.2 Simple Quantitative Cost/Benefit Analysis of Higher Operating Pressures......Page 136
4.7.3 Other Factors Affecting Choice of Pressure......Page 141
4.8.1 Carbon Monoxide Poisoning......Page 143
4.8.3 Using Pure Oxygen in Place of Air......Page 144
4.9.1 Small 12-W System......Page 145
4.9.2 Medium 2-kW System......Page 147
4.9.3 205-kW Fuel Cell Engine......Page 150
References......Page 151
5.1.2 Historical Importance......Page 153
5.1.3 Main Advantages......Page 154
5.2.1 Mobile Electrolyte......Page 156
5.2.2 Static Electrolyte Alkaline Fuel Cells......Page 159
5.2.3 Dissolved Fuel Alkaline Fuel Cells......Page 161
5.3 Operating Pressure and Temperature......Page 164
5.4.2 Sintered Nickel Powder......Page 166
5.4.4 Rolled Electrodes......Page 167
5.6 Problems and Development......Page 169
References......Page 170
6.1 Introduction......Page 172
6.2.1 Overall DMFC Reaction......Page 174
6.2.3 Anode Reactions in the PEM Direct Methanol FC......Page 175
6.2.4 Anode Fuel Feed......Page 177
6.2.5 Anode Catalysts......Page 178
6.3.1 How Fuel Crossover Occurs......Page 179
6.3.2 Standard Techniques for Reducing Fuel Crossover......Page 180
6.3.3 Fuel Crossover Techniques in Development......Page 181
6.4 Cathode Reactions and Catalysts......Page 182
6.5.1 Methanol Production......Page 183
6.5.2 Methanol Safety......Page 184
6.5.3 Methanol Compared to Ethanol......Page 186
6.5.4 Methanol Storage......Page 187
6.6 Direct Methanol Fuel Cell Applications......Page 188
References......Page 191
7.1 Introduction......Page 193
7.2.1 An Introduction to Fuel Reforming......Page 195
7.2.2 Fuel Utilization......Page 196
7.2.3 Bottoming Cycles......Page 198
7.2.4 The Use of Heat Exchangers - Exergy and Pinch Technology......Page 204
7.3.1 How It Works......Page 207
7.3.2 Performance of the PAFC......Page 212
7.3.3 Recent Developments in PAFC......Page 214
7.4.1 How It Works......Page 217
7.4.3 Cell Components in the MCFC......Page 220
7.4.4 Stack Configuration and Sealing......Page 225
7.4.5 Internal Reforming......Page 226
7.4.6 Performance of MCFCS......Page 228
7.4.7 Practical MCFC Systems......Page 232
7.5.1 How It Works......Page 237
7.5.2 SOFC Components......Page 239
7.5.3 Practical Design and Stacking Arrangements for the SOFC......Page 243
7.5.4 SOFC Performance......Page 250
7.5.5 SOFC Combined Cycles, Novel System Designs and Hybrid Systems......Page 251
7.5.6 Intermediate Temperature SOFCs......Page 255
References......Page 256
8.1 Introduction......Page 259
8.2.1 Petroleum......Page 262
8.2.2 Petroleum in Mixtures: Tar Sands, Oil Shales, Gas Hydrates, and LPG......Page 263
8.2.3 Coal and Coal Gases......Page 264
8.2.4 Natural Gas......Page 265
8.3 Bio-Fuels......Page 266
8.4.1 Fuel Cell Requirements......Page 268
8.4.2 Desulphurization......Page 269
8.4.3 Steam Reforming......Page 271
8.4.4 Carbon Formation and Pre-Reforming......Page 274
8.4.5 Internal Reforming......Page 276
8.4.7 Partial Oxidation and Autothermal Reforming......Page 278
8.4.9 Further Fuel Processing - Carbon Monoxide Removal......Page 280
8.5.1 Conventional Industrial Steam Reforming......Page 282
8.5.2 System Designs for Natural Gas Fed PEMFC and PAFC Plants with Steam Reformers......Page 283
8.5.3 Reformer and Partial Oxidation Designs......Page 287
8.6.1 General Issues......Page 293
8.6.2 Methanol Reforming for Vehicles......Page 294
8.6.3 Micro-Scale Methanol Reactors......Page 297
8.6.4 Gasoline Reforming......Page 299
8.7.1 Operation of Electrolysers......Page 300
8.7.3 Electrolyser Efficiency......Page 302
8.7.4 Generating at High Pressure......Page 303
8.8.1 Introduction......Page 305
8.8.2 Photosynthesis......Page 306
8.8.3 Hydrogen Production by Digestion Processes......Page 308
8.9.1 Introduction to the Problem......Page 309
8.9.2 Safety......Page 310
8.9.3 The Storage of Hydrogen as a Compressed Gas......Page 312
8.9.4 Storage of Hydrogen as a Liquid......Page 314
8.9.5 Reversible Metal Hydride Hydrogen Stores......Page 316
8.9.6 Carbon Nanofibres......Page 319
8.9.7 Storage Methods Compared......Page 321
8.10.2 Methanol......Page 323
8.10.3 Alkali Metal Hydrides......Page 325
8.10.4 Sodium Borohydride......Page 327
8.10.5 Ammonia......Page 331
8.10.6 Storage Methods Compared......Page 334
References......Page 335
9.1 Introduction......Page 339
9.2 Compressors - Types Used......Page 340
9.3 Compressor Efficiency......Page 342
9.4 Compressor Power......Page 344
9.5 Compressor Performance Charts......Page 345
9.6 Performance Charts for Centrifugal Compressors......Page 348
9.7 Compressor Selection - Practical Issues......Page 350
9.8 Turbines......Page 351
9.9 Turbochargers......Page 355
9.10 Ejector Circulators......Page 356
9.11 Fans and Blowers......Page 357
9.12 Membrane/Diaphragm Pumps......Page 358
References......Page 360
10.1 Introduction......Page 361
10.2.1 Switching Devices......Page 362
10.2.2 Switching Regulators......Page 364
10.3.1 Single Phase......Page 369
10.3.2 Three Phase......Page 374
10.3.3 Regulatory Issues and Tariffs......Page 376
10.3.4 Power Factor Correction......Page 378
10.4.1 General Points......Page 379
10.4.2 The Induction Motor......Page 380
10.4.3 The Brushless DC Motor......Page 382
10.4.4 Switched Reluctance Motors......Page 385
10.4.5 Motors Efficiency......Page 387
10.4.6 Motor Mass......Page 391
10.5 Fuel Cell/Battery or Capacitor Hybrid Systems......Page 392
References......Page 397
11.1 Introduction......Page 398
11.2 Energy Systems......Page 399
11.3.1 Importance of Well-to-Wheels Analysis......Page 400
11.3.2 Well-to-Tank Analysis......Page 401
11.3.3 Main Conclusions of the GM Well-to-Wheels Study......Page 403
11.4 Power-Train or Drive-Train Analysis......Page 404
11.5 Example System I - PEMFC Powered Bus......Page 406
11.6.2 Flow Sheet and Conceptual Systems Designs......Page 411
11.6.3 Detailed Engineering Designs......Page 415
11.6.4 Further Systems Analysis......Page 416
11.7 Closing Remarks......Page 417
References......Page 418
A1.1 Hydrogen Fuel Cell......Page 419
A1.2 The Carbon Monoxide Fuel Cell......Page 421
References......Page 422
A2.1 Introduction......Page 423
A2.2 Oxygen and Air Usage......Page 424
A2.3 Air Exit Flow Rate......Page 425
A2.4 Hydrogen Usage......Page 426
A2.6 Heat Produced......Page 427
A......Page 429
B......Page 430
C......Page 431
D......Page 432
E......Page 433
F......Page 434
H......Page 435
I......Page 436
M......Page 437
O......Page 439
P......Page 440
R......Page 442
S......Page 443
T......Page 444
V......Page 445
W......Page 446