Handbook of Gasification Technology

James G. Speight, PhD, has more than forty-five years of experience in energy, environmental science, and ethics. He is the author of more than 65 books in petroleum science, petroleum engineering, biomass and biofuels, and environmental sciences. Although he has always worked in private industry which focused on contract-based work, Dr. Speight has served as Adjunct Professor in the Department of Chemical and Fuels Engineering at the University of Utah and in the Departments of Chemistry and Chemical and Petroleum Engineering at the University of Wyoming. In addition, he was a Visiting Professor in the College of Science, University of Mosul, Iraq and has also been a Visiting Professor in Chemical Engineering at the University of Missouri-Columbia, the Technical University of Denmark, and the University of Trinidad and Tobago.

Preface xiv

Part 1: Synthesis Gas Production 1

1 Energy Sources and Energy Supply 3

1.1 Introduction 3

1.2 Typical Energy Sources 6

1.2.1 Natural Gas and Natural Gas Hydrates 6

1.2.2 The Crude Oil Family 7

1.2.3 Extra Heavy Crude Oil and Tar Sand Bitumen 10

1.3 Other Energy Sources 11

1.3.1 Coal 12

1.3.2 Oil Shale 14

1.3.3 Biomass 16

1.3.4 Solid Waste 19

1.4 Energy Supply 22

1.4.1 Economic Factors 22

1.4.2 Geopolitical Factors 22

1.4.3 Physical Factors 23

1.4.4 Technological Factors 24

1.5 Energy Independence 25

References 29

2 Overview of Gasification 35

2.1 Introduction 35

2.2 Gasification Processes 38

2.2.1 Processes 40

2.3 Feedstocks 41

2.3.1 Influence of Feedstock Quality 48

2.3.2 Feedstock Preparation 50

2.3.2.1 Crushing/Sizing/Drying 51

2.3.2.2 Pelletizing and Briquetting 51

2.4 Power Generation 52

2.5 Synthetic-Fuel Production 53

2.5.1 Gaseous Products 54

2.5.1.1 Synthesis Gas 54

2.5.1.2 Low Btu Gas 55

2.5.1.3 Medium Btu Gas 55

2.5.1.4 High Heat-Content Gas 56

2.5.2 Liquid Fuels 56

2.5.3 Tar 57

2.6 Advantages and Limitations 58

2.7 Market Developments and Outlook 60

References 62

3 Gasifier Types- Designs and Engineering 67

3.1 Introduction 67

3.2 Gasifier Types 68

3.2.1 Fixed Bed Gasifier 72

3.2.2 Fluid Bed Gasifier 75

3.2.3 Entrained Bed Gasifier 78

3.2.4 Molten Salt Gasifier 79

3.2.5 Plasma Gasifier 80

3.2.6 Slagging Gasifier 82

3.2.7 Other Types 83

3.3 Designs 83

3.3.1 General Design Aspects 84

3.3.2 Chemical and Physical Aspects 85

3.3.2.1 Chemical Aspects 85

3.3.2.2 Influence of Feedstock Quality 86

3.3.2.3 Mineral Matter Content 88

3.3.2.4 Mixed Feedstocks 89

3.3.2.5 Moisture Content 89

3.3.3 Physical Effects 90

3.3.3.1 Bulk Density 90

3.3.3.2 Char Gasification 90

3.3.3.3 Devolatilization and Volatile Matter Production 91

3.3.3.4 Particle Size and Distribution 92

3.4 Mechanism 92

3.4.1 Primary Gasification 93

3.4.2 Secondary Gasification 93

3.4.3 Hydrogasification 94

3.4.4 Catalytic Gasification 95

3.5 Energy Balance 96

3.6 Gasifier-Feedstock Compatibility 97

3.6.1 Feedstock Reactivity 97

3.6.2 Energy Content 98

3.7 Products 99

3.7.1 Gases 100

3.7.2 Tar 102

References 103

4 Chemistry, Thermodynamics, and Kinetics 107

4.1 Introduction 107

4.2 Chemistry 108

4.2.1 Pretreatment 109

4.2.2 Gasification Reactions 110

4.2.2.1 Primary Gasification 113

4.2.2.2 Secondary Gasification 114

4.2.2.3 Water Gas Shift Reaction 117

4.2.2.4 Carbon Dioxide Gasification 118

4.2.2.5 Hydrogasification 119

4.2.2.6 Methanation 120

4.2.2.7 Catalytic Gasification 121

4.2.2.8 Effect of Process Parameters 122

4.2.3 Physical Effects 122

4.3 Thermodynamics and Kinetics 124

4.3.1 Thermodynamics 126

4.3.2 Kinetics 127

4.4 Products 128

4.4.1 Gaseous Products 131

4.4.1.1 Low Btu Gas 132

4.4.1.2 Medium Btu Gas 133

4.4.1.3 High Btu Gas 134

4.4.1.4 Synthesis Gas 134

4.4.2 Liquid Products 135

4.4.3 Tar 136

4.4.4 Soot 136

4.4.5 Char 137

4.4.6 Slag 138

References 138

Part 2: Process Feedstocks 141

5 Coal Gasification 143

5.1 Introduction 143

5.2 Coal Types and Reactions 147

5.2.1 Types 148

5.2.2 Reactions 149

5.2.3 Properties 151

5.3 Processes 152

5.3.1 Coal Devolatilization 154

5.3.2 Char Gasification 154

5.3.3 Gasification Chemistry 155

5.3.4 Other Process Options 156

5.3.4.1 Hydrogasification 157

5.3.4.2 Catalytic Gasification 157

5.3.4.3 Plasma Gasification 158

5.3.5 Process Optimization 158

5.4 Product Quality 160

5.4.1 Low Btu Gas 160

5.4.2 Medium Btu Gas 161

5.4.3 High Btu Gas 161

5.4.4 Methane 162

5.4.5 Hydrogen 162

5.4.6 Other Products 163

5.5 Chemicals Production 164

5.5.1 Coal Tar Chemicals 164

5.5.2 Fischer-Tropsch Chemicals 166

5.5.2.1 Fischer-Tropsch Catalysts 167

5.5.2.2 Product Distribution 168

5.6 Advantages and Limitations 168

References 169

6 Gasification of Viscous Feedstock 173

6.1 Introduction 173

6.2 Viscous Feedstocks 177

6.2.1 Crude Oil Resids 178

6.2.2 Heavy Crude Oil 180

6.2.3 Extra Heavy Crude Oil 180

6.2.4 Tar Sand Bitumen 181

6.2.5 Other Feedstocks 182

6.2.5.1 Crude Oil Coke 183

6.2.5.2 Solvent Deasphalter Bottoms 185

6.2.5.3 Asphalt, Tar, and Pitch 187

6.3 Gas Production 188

6.3.1 Partial Oxidation Technology 189

6.3.1.1 Shell Gasification Process 191

6.3.1.2 Texaco Process 191

6.3.1.3 Phillips Process 192

6.3.2 Catalytic Partial Oxidation 192

6.4 Products 193

6.4.1 Gas Purification and Quality 194

6.4.2 Process Optimization 195

6.5 Advantages and Limitations 195

References 198

7 Gasification of Biomass 201

7.1 Introduction 201

7.2 Biomass Types and Mixed Feedstocks 205

7.2.1 Biomass 205

7.2.2 Black Liquor 209

7.2.3 Mixed Feedstocks 210

7.2.3.1 Biomass with Coal 211

7.2.3.2 Biomass with Waste 213

7.3 Chemistry 214

7.3.1 General Aspects 215

7.3.2 Reactions 218

7.3.2.1 Water Gas Shift Reaction 222

7.3.2.2 Carbon Dioxide Gasification 222

7.3.2.3 Hydrogasification 223

7.3.2.4 Methanation 224

7.4 Gasification Processes 225

7.4.1 Gasifiers 226

7.4.2 Fischer-Tropsch Synthesis 231

7.5 Gas Production and Products 232

7.5.1 Gas Production 233

7.5.2 Products 234

7.5.2.1 Synthesis Gas 235

7.5.2.2 Low-Btu Gas 236

7.5.2.3 Medium-Btu Gas 237

7.5.2.4 High-Btu Gas 237

7.5.3 Liquid Products 238

7.5.4 Solid Products 239

7.6 The Future 240

References 243

8 Gasification of Waste 249

8.1 Introduction 249

8.2 Waste Types 251

8.2.1 Solid Waste 251

8.2.2 Municipal Solid Waste 252

8.2.3 Industrial Solid Waste 253

8.2.4 Biosolids 254

8.2.5 Biomedical Waste 254

8.2.6 Mixed Feedstocks 255

8.3 Feedstock Properties and Plant Safety 255

8.4 Fuel Production 256

8.4.1 Pre-Processing 257

8.4.2 Gasifier Types 259

8.4.2.1 Counter-Current Fixed Bed Gasifier 259

8.4.2.2 Co-Current Fixed Bed Gasifier 259

8.4.2.3 Fluidized Bed Gasifier 260

8.4.2.4 Entrained Flow Gasifier 260

8.4.2.5 Other Types 261

8.4.3 Process Design 262

8.4.4 Plasma Gasification 263

8.5 Process Products 264

8.5.1 Synthesis Gas 264

8.5.2 Carbon Dioxide 265

8.5.3 Tar 265

8.5.4 Particulate Matter 267

8.5.5 Halogens/Acid Gases 267

8.5.6 Heavy Metals 268

8.5.7 Alkalis 269

8.5.8 Slag 269

8.6 Advantages and Limitation 270

References 271

9 Gas Cleaning 275

9.1 Introduction 275

9.2 Gas Streams 277

9.3 Water Removal 282

9.3.1 Absorption 282

9.3.2 Adsorption 283

9.3.3 Cryogenics 285

9.4 Acid Gas Removal 285

9.4.1 Adsorption 287

9.4.2 Absorption 288

9.4.3 Chemisorption 289

9.4.4 Other Processes 294

9.5 Removal of Condensable Hydrocarbons 297

9.5.1 Extraction 299

9.5.2 Absorption 300

9.5.3 Fractionation 300

9.5.4 Enrichment 301

9.6 Tar Removal 302

9.6.1 Physical Methods 302

9.6.2 Thermal Methods 304

9.7 Particulate Matter Removal 304

9.7.1 Cyclones 304

9.7.2 Electrostatic Precipitators 305

9.7.3 Granular-Bed Filters 305

9.7.4 Wet Scrubbers 306

9.8 Other Contaminant Removal 306

9.8.1 Nitrogen Removal 307

9.8.2 Ammonia Removal 308

9.8.3 Siloxane Removal 308

9.8.4 Alkali Metal Salt Removal 309

9.8.5 Biological Methods 309

9.8.5.1 Biofiltration 310

9.8.5.2 Bioscrubbing 312

9.8.5.3 Bio-Oxidation 313

9.9 Tail Gas Cleaning 313

9.9.1 Claus Process 314

9.9.2 SCOT Process 315

References 316

Part 3: Applications 321

10 Gasification in a Refinery 323

10.1 Introduction 323

10.2 Processes and Feedstocks 324

10.2.1 Gasification of Residua 327

10.2.2 Gasification of Residua with Coal 328

10.2.3 Gasification of Residua with Biomass 328

10.2.4 Gasification of Residua with Waste 330

10.3 Synthetic Fuel Production 332

10.3.1 Fischer-Tropsch Synthesis 334

10.3.2 Fischer Tropsch Liquids 334

10.3.3 Upgrading Fischer-Tropsch Liquids 336

10.3.3.1 Gasoline Production 338

10.3.3.2 Diesel Production 339

10.4 Sabatier-Senderens Process 340

10.4.1 Methanol Production 341

10.4.2 Dimethyl Ether Production 342

10.5 The Future 344

References 347

11 Hydrogen Production 353

11.1 Introduction 353

11.2 Processes Requiring Hydrogen 359

11.2.1 Hydrotreating 360

11.2.2 Hydrocracking 361

11.3 Feedstocks 362

11.4 Process Chemistry 362

11.5 Commercial Processes 364

11.5.1 Autothermal Reforming 365

11.5.2 Combined Reforming 366

11.5.3 Dry Reforming 367

11.5.4 Steam-Methane Reforming 367

11.5.5 Steam-Naphtha Reforming 370

11.6 Catalysts 370

11.6.1 Reforming Catalysts 371

11.6.2 Shift Conversion Catalysts 372

11.6.3 Methanation Catalysts 373

11.7 Hydrogen Purification 373

11.7.1 Cryogenic Separation 374

11.7.2 Desiccant Separation Systems 374

11.7.3 Membrane Separation Systems 374

11.7.4 Pressure Swing Adsorption Separation Systems 375

11.7.5 Wet Scrubbing Systems 376

11.8 Hydrogen Management 376

References 377

12 Fischer-Tropsch Process 381

12.1 Introduction 381

12.2 History and Development of the Process 385

12.3 Synthesis Gas 388

12.4 Production of Synthesis Gas 391

12.4.1 Feedstocks 393

12.4.2 Product Distribution 396

12.5 Process Parameters 397

12.6 Reactors and Catalysts 400

12.6.1 Reactors 400

12.6.2 Catalysts 402

12.7 Products and Product Quality 406

12.7.1 Products 407

12.7.2.1 Gases 407

12.7.1.2 Liquids 407

12.7.2 Product Quality 412

12.7.3 Upgrading Fischer-Tropsch Liquids 415

12.8 Fischer-Tropsch Chemistry 415

12.8.1 Chemical Principles 416

12.8.2 Refining Fischer-Tropsch Products 421

References 423

13 Fuels and Chemicals Production 427

13.1 Introduction 427

13.2 Historical Aspects and Overview 438

13.3 The Petrochemical Industry 440

13.4 Petrochemicals 445

13.4.1 Primary Petrochemicals 446

13.4.2 Products 447

13.4.3 Gaseous Fuels and Chemicals 453

13.4.3.1 Ammonia 453

13.4.3.2 Hydrogen 454

13.4.3.3 Synthetic Natural Gas 455

13.4.4 Liquid Fuels and Chemicals 455

13.4.4.1 Fischer-Tropsch Liquids 455

13.4.4.2 Methanol 456

13.4.4.3 Dimethyl Ether 456

13.4.4.4 Methanol-to-Gasoline and Olefins 456

13.4.4.5 Other Chemicals 457

13.5 The Future 457

References 463

14 Gasification – A Process for Now and the Future 467

14.1 Introduction 467

14.2 Applications and Products 468

14.2.1 Chemicals and Fertilizers 468

14.2.2 Substitute Natural Gas 469

14.2.3 Hydrogen for Crude Oil Refining 470

14.2.4 Transportation Fuels 470

14.2.5 Transportation Fuels from Tar Sand Bitumen 471

14.2.6 Power Generation 472

14.2.7 Waste-to-Energy 473

14.2.8 Biomass to Chemicals and Fuels 473

14.3 Environmental Benefits 475

14.3.1 Carbon Dioxide 476

14.3.2 Air Emissions 476

14.3.3 Solids Generation 477

14.3.4 Water Use 477

14.4 Gasification – The Future 477

14.4.1 The Process 478

14.4.2 Refinery of the Future 479

14.4.3 Economic Aspects 480

14.4.4 Market Outlook 481

14.5 Market Development 482

14.6 Outlook 483

References 485

Coversion Factors 487

Glossary 491

About the Author 519

Index 521