Series Preface ............................................... xiii
Acknowledgements ............................................... xv
List of Contributors ......................................... xvii
1 Introduction to Thermochemical Processing of Biomass into
Fuels, Chemicals, and Power .................................. 1
Robert C. Brown
1.1 Introduction ............................................ 1
1.2 Direct Combustion ....................................... 5
1.3 Gasification ............................................ 6
1.4 Fast Pyrolysis .......................................... 7
1.5 Hydrothermal Processing ................................. 8
1.6 Hydrolysis to Sugars .................................... 9
1.7 Technoeconomic Analysis ................................ 10
References .................................................. 10
2 Biomass Combustion .......................................... 13
Bryan M. Jenkins, Larry L Baxter and Jaap Koppejan
Nomenclature ................................................ 13
2.1 Introduction ........................................... 14
2.2 Combustion Systems ..................................... 15
2.2.1 Fuels ........................................... 15
2.2.2 Types of Combustor .............................. 18
2.3 Fundamentals of Biomass Combustion ..................... 23
2.3.1 Combustion Properties of Biomass ................ 23
2.3.2 Combustion Stoichiometry ........................ 29
2.3.3 Equilibrium ..................................... 32
2.3.4 Rates of Reaction ............................... 33
2.4 Pollutant Emissions and Environmental Impacts .......... 35
2.4.1 Oxides of Nitrogen and Sulfur ................... 36
2.4.2 Products of Incomplete Combustion ............... 38
2.4.3 Particulate Matter .............................. 38
2.4.4 Dioxin-like Compounds ........................... 38
2.4.5 Heavy Metals .................................... 40
2.4.6 Radioactive Species ............................. 40
2.4.7 Greenhouse Gas Emissions ........................ 40
References .................................................. 41
3 Gasification ................................................ 47
Richard L. Bain and Karl Broer
3.1 Introduction ........................................... 47
3.2 Fundamentals of Gasification ........................... 48
3.2.1 Heating and Drying .............................. 48
3.2.2 Pyrolysis ....................................... 49
3.2.3 Gas-Solid Reactions ............................. 50
3.2.4 Gas-phase Reactions ............................. 50
3.3 Feed Properties ........................................ 51
3.4 Classifying Gasifiers According to Method of Heating ... 54
3.4.1 Air-blown Gasifiers ............................. 54
3.4.2 Steam/Oxygen-blown Gasifiers .................... 56
3.4.3 Indirectly Heated Gasifiers ..................... 56
3.5 Classifying Gasifiers According to Transport
Processes .............................................. 58
3.5.1 Fixed Bed ....................................... 58
3.5.2 Bubbling Fluidized Bed .......................... 60
3.5.3 Circulating Fluidized Bed (CFB) ................. 61
3.5.4 Entrained Flow .................................. 62
3.6 Pressurized Gasification ............................... 63
3.7 Product Composition .................................... 64
3.7.1 Char and Tar ................................... 67
3.8 System Applications .................................... 68
3.8.1 Process Heat .................................... 68
3.8.2 Combined Heat and Power (CHP) ................... 68
3.8.3 Synthetic Fuels ................................. 74
References ............................................. 74
4 Syngas Cleanup, Conditioning, and Utilization ............... 78
David C. Dayton, Brian Turk and Raghubir Gupta
4.1 Introduction ........................................... 78
4.2 Syngas Cleanup and Conditioning ........................ 79
4.2.1 Particulates .................................... 81
4.2.2 Sulfur .......................................... 83
4.2.3 Ammonia Decomposition and HCN Removal ........... 84
4.2.4 Alkalis and Heavy Metals ........................ 85
4.2.5 Chlorides ....................................... 85
4.2.6 Tars ............................................ 86
4.3 Syngas Utilization ..................................... 89
4.3.1 Syngas to Gaseous Fuels ......................... 90
4.3.2 Syngas to Liquid Fuels .......................... 98
4.4 Summary and Conclusions ............................... 111
References ................................................. 115
5 Fast Pyrolysis ............................................. 124
Robbie H. Venderbosch and Wolter Prins
5.1 Introduction .......................................... 124
5.1.1 Fundamentals of Pyrolysis ...................... 125
5.1.2 Effect of Ash .................................. 128
5.2 Bio-oil Properties .................................... 128
5.2.1 Composition and Stability ..................... 131
5.3 Fast Pyrolysis Process Technologies ................... 134
5.3.1 Entrained Downflow ............................. 135
5.3.2 Ablative Reactor ............................... 135
5.3.3 Bubbling Fluidized Bed ......................... 138
5.3.4 Circulating Fluidized Bed (CFB) ................ 141
5.3.5 Moving-grate Vacuum Pyrolysis .................. 142
5.3.6 Rotating-cone Pyrolyzer ........................ 142
5.4 Bio-oil Fuel Applications ............................. 143
5.4.1 Gas Turbines ................................... 148
5.4.2 Gasification ................................... 149
5.4.3 Transportation Fuels ........................... 149
5.5 Chemicals from Bio-oil ................................ 150
5.5.1 Whole Bio-oil .................................. 150
5.5.2 Fractions of Bio-oil ........................... 151
5.6 Concluding Remarks .................................... 152
Acknowledgements ........................................... 153
References ................................................. 153
6 Upgrading Fast Pyrolysis Liquids ........................... 157
Anthony V. Bridgwater
6.1 Introduction to Fast Pyrolysis and Bio-oil ............ 157
6.1.1 Introduction ................................... 157
6.1.2 Bio-oil General Characteristics ................ 157
6.2 Liquid Characteristics and Quality .................... 159
6.3 Significant Factors Affecting Characteristics ......... 159
6.3.1 Feed Material .................................. 159
6.3.2 Reactors ....................................... 164
6.4 Norms and Standards ................................... 165
6.5 Bio-oil Upgrading ..................................... 165
6.5.1 Acidity or Low pH .............................. 165
6.5.2 Aging .......................................... 165
6.5.3 Alkali Metals .................................. 166
6.5.4 Char ........................................... 166
6.5.5 Chlorine ....................................... 167
6.5.6 Color .......................................... 167
6.5.7 Contamination of Feed .......................... 168
6.5.8 Distillability ................................. 168
6.5.9 High Viscosity ................................. 168
6.5.10 Inhomogeneity .................................. 169
6.5.11 Low H:C Ratio .................................. 169
6.5.12 Low pH ......................................... 169
6.5.13 Materials Incompatibility ...................... 169
6.5.14 Miscibility with Hydrocarbons .................. 169
6.5.15 Nitrogen ....................................... 170
6.5.16 Other Solid Particulates, Excluding Char ....... 170
6.5.17 Oxygen Content ................................. 170
6.5.18 Phase Separation or Inhomogeneity .............. 170
6.5.19 Smell .......................................... 170
6.5.20 Structure of Bio-oil ........................... 171
6.5.21 Sulfur ......................................... 171
6.5.22 Temperature Sensitivity ........................ 171
6.5.23 Toxicity ....................................... 172
6.5.24 Viscosity ...................................... 172
6.5.25 Water Content .................................. 172
6.6 Chemical and Catalytic Upgrading of Bio-oil ........... 172
6.6.1 Physical Upgrading of Bio-oil .................. 172
6.6.2 Catalytic Upgrading of Bio-oil ................. 174
6.6.3 Other Methods for Chemical Upgrading of
Bio-oil ........................................ 180
6.6.4 Hydrogen ....................................... 182
6.6.5 Chemicals ...................................... 182
6.7 Conclusions ........................................... 187
References ................................................. 188
7 Hydrothermal Processing .................................... 200
Douglas C. Elliott
7.1 Introduction .......................................... 200
7.2 Background ............................................ 202
7.2.1 Why Hydrothermal Processing? ................... 202
7.2.2 History of Hydrothermal Liquefaction Process
Development .................................... 202
7.2.3 History of Hydrothermal Gasification Process
Development .................................... 203
7.3 Fundamentals .......................................... 203
7.3.1 Subcritical Processing in the Liquid Phase ..... 204
7.3.2 Supercritical Processing in the Vapor Phase .... 204
7.4 Hydrothermal Liquefaction ............................. 205
7.4.1 State of Technology ............................ 205
7.4.2 Process Descriptions ........................... 205
7.4.3 Product Evaluation ............................. 207
7.4.4 Product Utilization ............................ 212
7.4.5 Process Mechanism Evaluations .................. 213
7.4.6 Recent Fundamental Evaluations ................. 216
7.4.7 Conclusions Relative to Hydrothermal
Liquefaction ................................... 216
7.5 Hydrothermal Gasification ............................. 217
7.5.1 State of Technology ........................... 217
7.5.2 Process Description ............................ 217
7.5.3 Catalytic Hydrothermal Gasification ............ 218
7.5.4 Hydrothermal Gasification in Supercritical
Water .......................................... 221
7.5.5 Conclusions Relative to Hydrothermal
Gasification ................................... 223
7.6 Pumping Biomass into Hydrothermal Processing
Systems ............................................... 223
7.7 Conclusions of Hydrothermal Processing ................ 226
References ............................................ 226
8 Catalytic Conversion of Sugars to Fuels .................... 232
Geoffrey A. Tompsett, Ning Li and George W. Huber
8.1 Introduction .......................................... 232
8.1.1 Overview ....................................... 232
8.1.2 Desired Targets and Overall Reactions .......... 233
8.1.3 Thermodynamics of Chemistry Conversion ......... 235
8.2 Chemistry of Sugars ................................... 238
8.3 Hydrogen from Sugars .................................. 242
8.3.1 Overall Reaction and Thermodynamics ............ 242
8.3.2 Reaction Mechanism ............................. 244
8.3.3 Aqueous-Phase Reforming ........................ 244
8.3.4 Supercritical Reactions - Reforming of
Sugars ......................................... 246
8.4 Sugar to Light Alkanes ................................ 249
8.4.1 Overall Reaction and Thermodynamics ............ 249
8.4.2 Dehydration of Sugars .......................... 251
8.4.3 Hydrogenation Reactions of Sugars .............. 252
8.4.4 Combined Dehydration/Hydrogenation ............. 254
8.5 Sugars to Oxygenates .................................. 254
8.5.1 Targeted Products and Thermodynamics ........... 254
8.5.2 Biphasic Dehydration Reactions (HMF and
Furfural Production) ........................... 255
8.5.3 Hydrogenation .................................. 256
8.5.4 Other Oxygenate Fuels from Sugars .............. 258
8.6 Sugars to Larger Alkanes .............................. 261
8.6.1 Overall Reaction and Chemistry ................. 261
8.6.2 C-C Bond Formation ............................. 266
8.6.3 Hydrogenation/Dehydration ...................... 268
8.7 Sugar Conversion to Aromatics ......................... 269
8.7.1 Overall Reaction and Thermodynamics ............ 269
8.7.2 Catalytic Fast Pyrolysis ....................... 270
8.7.3 Aromatics from Sugar Fragments in the Aqueous
Phase .......................................... 271
8.8 Conclusions and Summary ............................... 271
Acknowledgements ...................................... 272
References ............................................ 272
9 Hybrid Processing .......................................... 280
DongWon Choi, Alan A. DiSpirito, David C. Chipman and
Robert C. Brown
9.1 Introduction .......................................... 280
9.1.1 Biorefineries .................................. 280
9.1.2 Hybrid Thermochemical/Biochemical Processing ... 281
9.2 Syngas Fermentation ................................... 282
9.2.1 Catalytic Conversions of Syngas: Chemical
Versus Biological .............................. 282
9.2.2 Fermentation of Syngas ......................... 282
9.2.3 Microbial CO Metabolism ........................ 283
9.2.4 Microbial H2 Metabolism ........................ 288
9.2.5 Microbial CH4 Metabolism ....................... 289
9.2.6 Photosynthetic CO2 Metabolism .................. 290
9.2.7 Current Industrial Progress of Syngas
Fermentation ................................... 291
9.2.8 Problems and Future Perspectives ............... 292
9.3 Bio-oil Fermentation .................................. 295
9.3.1 Levoglucosan Utilizers ......................... 296
9.3.2 Current Status of Levoglucosan Fermentation .... 297
9.3.3 Future Perspectives ............................ 298
References ............................................ 299
10 Costs of Thermochemical Conversion of Biomass to Power
and Liquid Fuels ........................................... 307
Mark M. Wright and Robert C. Brown
10.1 Introduction .......................................... 307
10.2 Electric Power Generation ............................. 308
10.2.1 Direct Combustion to Power ..................... 308
10.2.2 Gasification to Power .......................... 308
10.2.3 Fast Pyrolysis to Power ........................ 309
10.3 Liquid Fuels via Gasification ......................... 309
10.3.1 Gasification to Hydrogen ....................... 309
10.3.2 Gasification to Methanol ....................... 311
10.3.3 Gasification to Mixed Alcohols ................. 312
10.3.4 Gasification to Fischer-Tropsch Liquids ........ 313
10.3.5 Gasification and Syngas Fermentation to PHA
and Co-Product Hydrogen ........................ 315
10.4 Liquid Fuels via Fast Pyrolysis ....................... 316
10.4.1 Bio-oil Fermentation to Ethanol ................ 316
10.4.2 Bio-oil Upgrading to Gasoline and Diesel ....... 316
10.4.3 Bio-oil Gasification to Liquid Fuels ........... 318
10.5 Summary and Conclusions ............................... 319
References ............................................ 321
Index ......................................................... 323
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