Fuel Cell Systems Explained

by Dicks, Andrew; Larminie, James

• ISBN13: 9780471490265
• ISBN10: 0471490261
• Format: Hardcover
• Copyright: 2000-06-01
• Publisher: John Wiley & Sons Inc

Summary

Provides a clear, accessible introduction to fuel cell technology by setting out the working methods, behaviour, limitations, features and the potential of all major fuel cell types currently in commercial development. Fuel cells are emerging as the practical and versatile solution to the problem of alternative power sources and this book provides a new understanding of fuel cell technology. Assuming no prior knowledge of fuel cell chemistry, this reference comprehensively brings together all of the key topics encompassed by this diverse field. Features include: * An overview of fuel cell technology, explaining the operation and fundamental thermodynamics of fuel cells with a clear and well illustrated account of cell construction. * Detailed accounts of the problems faced by designers of all major fuel cell types currently in commercial development including water management, cooling, air supply, construction methods, operating pressure and reactant composition. * Up to date coverage of Proton Exchange Membrane (PEM) cells. * Description of the main devices for moving, compressing and expanding the gases in fuel cell systems, including relevant formulas. * Coverage of the complete fuel cell power system including compressors, turbines, fuel processors, hydrogen storage devices, inverters and motors. * Clear treatment of the electrical and electronic sub-systems, including regulators, grid inter-ties, electric motors and hybrid fuel cell/battery systems. An essential guide to the principles, design and application of fuel cell systems, this timely book will prove invaluable to those working and studying within this increasingly important field. Practising electrical, automotive, power and control engineers, undergraduates and graduate students in the areas of thermodynamics, electrical power systems and automotive engineering will find their knowledge and understanding of this developing area greatly enhanced by the Authors' informed and easy-to-read style.

Author Biography

James Larminie: Oxford Brookes University, UK Andrew Dicks: University of Queensland, Australia

Table of Contents

Foreword	xi
Dr Gary Acres OBE
Acknowledgements	xiii
Abbreviations	xv
Symbols	xvii
Introduction	1	(16)
Hydrogen Fuel Cells - Basic Principles	1	(4)
What Limits the Current?	5	(2)
Connecting Cells in Series - the Bipolar Plate	7	(3)
Fuel Cell Types	10	(2)
Other Parts of a Fuel Cell System	12	(2)
Figures used to Compare Systems	14	(1)
Advantages and Applications	15	(2)
Efficiency and Open Circuit Voltage	17	(20)
Energy and the EMF of the Hydrogen Fuel Cell	17	(5)
The Open Circuit Voltage of other Fuel Cells and Batteries	22	(1)
Efficiency and Efficiency Limits	23	(4)
Efficiency and the Fuel Cell Voltage	27	(1)
The Effect of Pressure and Gas Concentration	28	(7)
The Nernst equation	28	(4)
Hydrogen partial pressure	32	(1)
Fuel and oxidant utilisation	32	(1)
System pressure	33	(1)
An application - blood alcohol measurement	34	(1)
Summary	35	(2)
References	36	(1)
Operational Fuel Cell Voltages	37	(24)
Introduction	37	(2)
Terminology	39	(1)
Fuel Cell Irreversibilities - Causes of Voltage Drop	39	(1)
Activation Losses	40	(6)
The Tafel equation	40	(2)
The constants in the Tafel equation	42	(3)
Reducing the activation overvoltage	45	(1)
Summary of activation overvoltage	45	(1)
Fuel Crossover and Internal Currents	46	(3)
Ohmic Losses	49	(1)
Mass Transport or Concentration Losses	50	(2)
Combining the Irreversibilities	52	(1)
The Charge Double Layer	53	(3)
Distinguishing the Different Irreversibilities	56	(3)
References	59	(2)
Proton Exchange Membrane Fuel Cells	61	(48)
Overview	61	(2)
How the Polymer Electrolyte Works	63	(3)
Electrodes and Electrode Structure	66	(3)
Water Management in the PEMFC	69	(12)
Overview of the problem	69	(2)
Air flow and water evaporation	71	(6)
Running PEM fuel cells without extra humidification	77	(1)
External humidification	78	(3)
PEM Fuel Cell Cooling and Air Supply	81	(3)
Cooling using the cathode air supply	81	(1)
Separate reactant and cooling air	81	(2)
Water cooling of PEM fuel cells	83	(1)
PEM Fuel Cell Construction Methods	84	(6)
Introduction	84	(1)
Bipolar plates for PEM fuel cells	84	(3)
Other Topologies	87	(3)
Operating Pressure	90	(8)
Outline of the problem	90	(2)
Simple quantitative cost/benefit analysis of higher operating pressures	92	(4)
Other factors affecting choice of pressure	96	(2)
Reactant Composition	98	(3)
Carbon monoxide poisoning	98	(2)
Methanol and other liquid fuels	100	(1)
Using pure oxygen in place of air	100	(1)
Example Systems	101	(8)
Small 12 Watt system	101	(2)
Medium 2 kW system	103	(3)
Large 260 kW system	106	(1)
References	107	(2)
Alkaline Electrolyte Fuel Cells	109	(14)
Historical Background and Overview	109	(2)
Types of Alkaline Electrolyte Fuel Cell	111	(5)
Mobile electrolyte	111	(2)
Static electrolyte alkaline fuel cells	113	(1)
Dissolved fuel alkaline fuel cells	114	(2)
Electrodes for Alkaline Electrolyte Fuel Cells	116	(2)
Introduction	116	(1)
Sintered nickel powder	116	(1)
Raney metals	116	(1)
Rolled electrodes	117	(1)
Operating Pressure and Temperature	118	(3)
Problems and Development	121	(2)
References	122	(1)
Medium and High Temperature Fuel Cells	123	(58)
Introduction	123	(2)
Common Features	125	(12)
An introduction to fuel reforming	125	(1)
Fuel utilisation	126	(2)
Bottoming cycles	128	(6)
The use of heat exchangers - exergy and pinch technology	134	(3)
The Phosphoric Acid Fuel Cell (PAFC)	137	(9)
How it works	137	(5)
Performance of the PAFC	142	(2)
Recent developments in PAFC	144	(2)
The Molten Carbonate Fuel Cell (MCFC)	146	(18)
How it works	146	(3)
Implications of using a molten carbonate electrolyte	149	(1)
Cell components in the MCFC	150	(4)
Stack configuration and sealing	154	(2)
Internal reforming	156	(1)
Performance of MCFCs	157	(4)
Practical MCFC systems	161	(3)
The Solid Oxide Fuel Cell	164	(17)
How it works	164	(2)
SOFC components	166	(2)
Design and stacking arrangements for the SOFC	168	(5)
SOFC performance	173	(2)
SOFC combined cycles, novel system designs and hybrid systems	175	(2)
References	177	(4)
Fuelling Fuel Cells	181	(48)
Introduction	181	(1)
Fossil Fuels	182	(5)
Petroleum	182	(2)
Petroleum in mixtures: Tar sands, oil shales, gas hydrates and LPG	184	(1)
Coal and coal gases	184	(2)
Natural gas	186	(1)
Bio-fuels	187	(1)
The basics of fuel processing	188	(13)
Fuel cell requirements	188	(1)
Desulphurisation	189	(1)
Steam reforming	190	(3)
Carbon formation and pre-reforming	193	(2)
Internal reforming	195	(2)
Direct hydrocarbon oxidation	197	(1)
Partial oxidation and autothermal reforming	198	(1)
Hydrogen generation by pyrolysis or thermal cracking of hydrocarbons	199	(1)
Further fuel processing -- carbon monoxide removal	199	(2)
Practical Fuel Processing -- Stationary Applications	201	(6)
Natural gas fed PEMFC and PAFC plants with steam reformers	201	(3)
Reformer and partial-oxidation designs	204	(3)
Practical Fuel Processing -- Mobile Applications	207	(5)
General issues	207	(1)
Methanol reforming	208	(2)
Methanol CPO/autothermal reforming	210	(101)
Gasoline reforming	311	(99)
Hydrogen Storage	212	(17)
Introduction to the problem	212	(2)
Safety	214	(2)
The storage of hydrogen as a compressed gas	216	(2)
Storage of hydrogen as a liquid	218	(3)
Reversible metal hydride hydrogen stores	221	(2)
Alkali metal hydrides	223	(1)
Storage methods compared	224	(3)
References	227	(2)
Compressors, Turbines, Ejectors, Fans, Blowers and Pumps	229	(22)
Introduction	229	(1)
Compressors -- Types Used	230	(2)
Compressor Efficiency	232	(3)
Compressor Power	235	(1)
Compressor Performance Charts	235	(4)
Performance Charts for Centrifugal Compressors	239	(1)
Compressor Selection -- Practical Issues	240	(2)
Turbines	242	(2)
Turbochargers	244	(2)
Ejector Circulators	246	(1)
Fans and Blowers	247	(2)
Membrane/Diaphragm Pumps	249	(2)
References	250	(1)
Delivering Fuel Cell Power	251	(52)
Introduction	251	(1)
DC Regulation and Voltage Conversion	252	(7)
Switching devices	252	(2)
Switching regulators	254	(5)
Inverters	259	(10)
Single phase	259	(4)
Three phase	263	(3)
Regulatory issues and tariffs	266	(2)
Power factor correction	268	(1)
Electric Motors	269	(12)
General points	269	(1)
The induction motor	269	(3)
The brushless DC motor	272	(3)
Switched reluctance motors	275	(3)
Motor efficiency	278	(2)
Motor mass	280	(1)
Fuel Cell/Battery Hybrid Systems	281	(5)
Example System	286	(4)
Closing Remarks	290	(3)
References	291	(2)
Appendices
A1 Change in Molar Gibbs Free Energy Calculations	293	(4)
A1.1 Hydrogen Fuel Cell	293	(2)
A1.2 The Carbon Monoxide Fuel Cell	295	(1)
References	296	(1)
A2 Useful Fuel Cell Equations	297	(6)
A2.1 Introduction	297	(1)
A2.2 Oxygen and Air Usage	298	(1)
A2.3 Air Exit Flowrate	299	(1)
A2.4 Hydrogen Usage	300	(1)
A2.5 Water Production	301	(1)
A2.6 Heat Produced	302	(1)
Index	303