Catalytic Air Pollution Control

Preface xiii

Acknowledgments xvii

Acknowledgments, First Edition xix

Acknowledgments, Second Edition xxi

I Fundamentals 1

1. Catalyst Fundamentals 3

1.1 Introduction 3

1.2 Catalyzed Versus Noncatalyzed Reactions 3

1.3 Catalytic Components 13

1.4 Selectivity 14

1.5 Promoters and their Effect on Activity and Selectivity 15

1.6 Dispersed Model for Catalytic Component on Carrier: Pt on Al2O3 16

1.7 Chemical and Physical Steps in Heterogeneous Catalysis 18

1.8 Practical Significance of Knowing the Rate-Limiting Step 21

References 22

Questions 23

2. The Preparation of Catalytic Materials: Carriers, Active Components, and Monolithic Substrates 24

2.1 Introduction 24

2.2 Carriers 24

2.3 Making the Finished Catalyst 30

2.4 Nomenclature for Dispersed Catalysts 32

2.5 Monolithic Materials as Catalyst Substrates 32

2.6 Preparing Monolithic Catalysts 36

2.7 Catalytic Monoliths 37

2.8 Catalyzed Monolith Nomenclature 38

2.9 Precious Metal Recovery from Monolithic Catalysts 38

References 38

Questions 40

3. Catalyst Characterization 41

3.1 Introduction 41

3.2 Physical Properties of Catalysts 42

3.3 Chemical and Physical Morphology Structures of Catalytic Materials 48

3.4 Techniques for Fundamental Studies 60

References 61

Questions 62

4. Monolithic Reactors for Environmental Catalysis 63

4.1 Introduction 63

4.2 Chemical Kinetic Control 63

4.3 The Arrhenius Equation and Reaction Parameters 66

4.4 Bulk Mass Transfer 69

4.5 Reactor Bed Pressure Drop 74

4.6 Summary 76

References 76

Questions 77

5. Catalyst Deactivation 79

5.1 Introduction 79

5.2 Thermally Induced Deactivation 79

5.3 Poisoning 88

5.4 Washcoat Loss 94

5.5 General Comments on Deactivation Diagnostics in Monolithic Catalysts for Environmental Applications 95

References 97

Questions 98

II Mobile Source 101

6. Automotive Catalyst 103

6.1 Emissions and Regulations 103

6.2 The Catalytic Reactions for Pollution Abatement 106

6.3 The Physical Structure of the Catalytic Converter 107

6.4 First-Generation Converters: Oxidation Catalyst (1976-1979) 114

6.5 NOx, Co and HC Reduction: the Second Generation: The Three-Way Catalyst (1979-1986) 118

6.6 Vehicle Test Procedures (U.S., European, and Japanese) 123

6.7 NOx, Co, and HC Reduction: the Third Generation (1986-1992) 128

6.8 Palladium TWC Catalyst: The Fourth Generation (Mid-1990s) 136

6.9 Low-Emission Catalyst Technologies 138

6.10 Modern TWC Technologies for the 2000s 146

6.11 Toward a Zero-Emission Stoichiometric Spark-Ignited Vehicle 148

6.12 Engineered Catalyst Design 153

6.13 Lean-Burn Spark-Ignited Gasoline Engine 157

References 163

Questions 174

7. Automotive Substrates 176

7.1 Introduction to Ceramic Substrates 176

7.2 Requirements for Substrates 178

7.3 Design/Sizing of Substrates 180

7.4 Physical Properties of Substrates 185

7.5 Physical Durability 194

7.6 Advances in Substrates 207

7.7 Commercial Applications 222

7.8 Summary 229

References 230

Questions 236

8. Diesel Engine Emissions 238

8.1 Introduction 238

8.2 Worldwide Diesel Emission Standards 241

8.3 NOx-Particulate Trade-Off 245

8.4 Analytical Procedures for Particulates 245

8.5 Particulate Removal 246

8.6 NOx Reduction Technologies 263

8.7 2007 Commercial System Designs (PM Removal Only) 272

8.8 2010 Commercial System Approaches under Development (PM and NOx Removal) 275

8.9 Retrofit and Off-Highway 281

8.10 Natural Gas Engines 282

References 283

Questions 292

9. Diesel Catalyst Supports and Particulate Filters 295

9.1 Introduction 295

9.2 Health Effects of Diesel Particulate Emissions 298

9.3 Diesel Oxidation Catalyst Supports 298

9.4 Design/Sizing of a Diesel Particulate Filter 302

9.5 Regeneration Techniques 313

9.6 Physical Properties and Durability 319

9.7 Advances in Diesel Filters 324

9.8 Applications 340

9.9 Summary 350

References 352

Questions 355

10. Ozone Abatement within Jet Aircraft 357

10.1 Introduction 357

10.2 Ozone Abatement 358

10.3 Deactivation 363

10.4 Analysis of In-Flight Samples 365

10.5 New Technology 371

References 372

Questions 373

III Stationary Sources 375

11. Volatile Organic Compounds 377

11.1 Introduction 377

11.2 Catalytic Incineration 379

11.3 Halogenated Hydrocarbons 383

11.4 Food Processing 390

11.5 Wood Stoves 392

11.6 Process Design 394

11.7 Deactivation 394

11.8 Regeneration of Deactivated Catalysts 395

References 399

Questions 401

12. Reduction of No X 403

12.1 Introduction 403

12.2 Nonselective Catalytic Reduction of NOx 404

12.3 Selective Catalytic Reduction of NOx 407

12.4 Commercial Experience 417

12.5 Nitrous Oxide (N2O) 427

12.6 Catalytically Supported Thermal Combustion 429

References 434

Questions 439

13. Carbon Monoxide and Hydrocarbon Abatement from Gas Turbines 440

13.1 Introduction 440

13.2 Catalyst for CO Abatement 441

13.3 Non-Methane Hydrocarbon (NMHC) Removal 443

13.4 Oxidation of Reactive Hydrocarbons 444

13.5 Oxidation of Unreactive Light Paraffins 445

13.6 Catalyst Deactivation 447

References 448

Questions 449

14. Small Engines 450

14.1 Introduction 450

14.2 Emissions 450

14.3 EPA Regulations 451

14.4 Catalyst for Handheld and Nonhandheld Engines 455

14.5 Catalyst Durability 463

References 464

Questions 466

IV New and Emerging Technologies 467

15. Ambient Air Cleanup 469

15.1 Introduction 469

15.2 Premair® Catalyst Systems 470

15.3 Other Approaches 478

References 479

Questions 481

16. Fuel Cells and Hydrogen Generation 482

16.1 Introduction 482

16.2 Low-Temperature PEM Fuel Cell Technology 488

16.3 The Ideal Hydrogen Economy 495

16.4 Conventional Hydrogen Generation 496

16.5 Hydrogen Generation from Natural Gas for PEM Fuel Cells 499

16.6 Other Fuel Cell Systems 505

References 511

Questions 517

Index 518