Preface ...................................................... xvii
About the Authors ............................................. xix
Chapter 1 Definition and Structure of Asphaltenes .............. 1
1.1 Introduction ............................................... 1
1.2 Variables Affecting the Asphaltenes Precipitation .......... 8
1.2.1 Nature of the Crude ................................. 8
1.2.2 Solvent Type ....................................... 10
1.2.3 Contact Time ....................................... 10
1.2.4 Solvent-to-Oil Ratio ............................... 12
1.2.5 Temperature ........................................ 12
1.2.6 Pressure ........................................... 14
1.3 Reversibility of Asphaltenes Precipitation ................ 19
1.4 Elemental Composition of Asphaltenes ...................... 20
1.5 Asphaltenes Density ....................................... 25
1.6 Characterization of Asphaltenes ........................... 28
1.6.1 Infrared Spectroscopy .............................. 28
1.6.2 Molecular Weight of Asphaltenes .................... 30
1.6.2.1 Vapor Pressure Osmometry (VPO) ............ 30
1.6.2.2 Size Exclusion Chromatography (SEC) ....... 37
1.6.2.3 Mass Spectroscopy ......................... 41
1.6.3 Ultraviolet (UV) Fluorescence ...................... 44
1.6.4 X-Ray Diffraction (XRD) ............................ 48
1.6.5 Nuclear Magnetic Resonance ......................... 51
1.6.6 Small Angle Scattering ............................. 55
1.6.7 Microscopic Analysis ............................... 59
1.7 Role of Resins in Stabilizing Asphaltenes ................. 68
1.8 Concluding Remarks ........................................ 73
References ..................................................... 74
Chapter 2 Hydroprocessing of Heavy Oils ....................... 87
2.1 Introduction .............................................. 87
2.2 Composition of Heavy Petroleum Feeds ...................... 98
2.2.1 Role of Asphaltene ................................ 102
2.3 Upgrading of Heavy Oils .................................. 103
2.4 Components of Hydroprocessing Catalyst ................... 109
2.4.1 Supports and Catalysts Preparation/Composition .... 110
2.4.2 Role of Catalytic Sites in Heavy Oil Reaction
Mechanism ......................................... 111
2.5 Effect of Catalyst Properties on Hydroprocessing
Activities ............................................... 115
2.5.1 Effect of Textural Properties of Catalysts ........ 115
2.5.2 Effect of Catalyst Composition or Support
Effect ............................................ 124
2.5.3 Effect of Catalyst Shape, Size, Mechanical
Properties, and Reactor Pressure Drop ............. 128
2.6 Catalyst Life (Catalyst Stability) ....................... 134
2.7 Concluding Remarks ....................................... 150
References .................................................... 151
Chapter 3 Changes in Asphaltenes during Hydrotreating ........ 161
3.1 Introduction ............................................. 161
3.2 Asphaltenes Characterization after Hydrotreating ......... 162
3.2.1 Elemental Analysis ................................ 162
3.2.2 Metals Content .................................... 163
3.2.3 Changes in Molecular Weight and Size .............. 168
3.2.3.1 Molecular Weight by Vapor Pressure
Osmometry (VPO) .......................... 168
3.2.3.2 Molecular Weight Distributions ........... 173
3.2.4 Nuclear Magnetic Resonance ........................ 176
3.2.5 X-Ray Diffraction ................................. 179
3.2.6 Microscopic Analysis .............................. 182
3.2.6.1 SEM Analysis ............................. 182
3.2.6.2 ТЕМ Analysis ............................. 185
3.3 Influence of Reaction Conditions on Asphaltene
Structure ................................................ 188
3.3.1 Influence of Temperature .......................... 188
3.3.2 Influence of Space Velocity ....................... 192
3.3.3 Influence of Pressure ............................. 194
3.3.4 Influence of Catalyst ............................. 194
3.4 Concluding Remarks ....................................... 200
References .................................................... 200
Chapter 4 Catalyst Deactivation Due to Asphaltenes ........... 205
4.1 Introduction ............................................. 205
4.2 Origin of Coke, Mechanism of Its Formation, and
Properties ............................................... 206
4.3 The Role of the Asphaltenes in Coke Formation ............ 212
4.3.1 Thermal Reaction .................................. 213
4.3.2 Catalytic Reaction ................................ 217
4.4 Catalyst Deactivation in Fixed-Bed Reactors .............. 230
4.5 Influence of Coke and Metals Deposition on Catalyst
Deactivation During Hydroprocessing ...................... 233
4.5.1 Initial Catalyst Deactivation ..................... 234
4.5.1.1 Initial Coke Deposition .................. 234
4.5.1.2 Initial Metals Deposition ................ 237
4.5.2 Steady State Deactivation ......................... 237
4.5.2.1 Intermediate Coke Deposition ............. 237
4.5.2.2 Intermediate Metals Deposition
(HDM Reaction Mechanism) ................. 238
4.5.3 Final Catalyst Deactivation ....................... 241
4.6 Characterization of Spent Catalysts ...................... 244
4.6.1 Temperature Programmed Oxidation (TPO) ............ 244
4.6.2 Nuclear Magnetic Resonance (NMR) .................. 246
4.6.3 Raman Spectrometry ................................ 246
4.6.4 SEM-EDX Analysis .................................. 248
4.6.5 Thermogravimetric Analysis (TGA) and Kinetics of
Coking ............................................ 252
4.7 Effect of Reaction Conditions on Catalyst Deactivation ... 256
4.7.1 Influence of Temperature .......................... 256
4.7.2 Influence of Hydrogen Pressure .................... 257
4.7.3 Influence of the Feedstock ........................ 257
4.7.4 Influence of the Catalyst and Its Properties ...... 258
4.8 Catalyst Formulation and Its Effect on Asphaltenes
Conversion ............................................... 262
4.9 Alternatives Approaches for Preventing Coke Deposition ... 264
4.9.1 Use of Fine Solids ................................ 264
4.9.2 Solvent Deasphalting .............................. 266
4.10 Regeneration and Rejuvenation of Spent Catalyst .......... 269
4.10.1 Regeneration by Calcination ....................... 269
4.10.2 Rejuvenation and Metals Removal by Leaching ....... 271
4.11 Concluding Remarks ....................................... 274
References .................................................... 274
Chapter 5 Sediments Formation ................................ 285
5.1 Introduction ............................................. 285
5.2 Sediments Analysis or Sediment Tests ..................... 288
5.3 Possible Reaction Mechanism and Compatibilities between
the Components ........................................... 290
5.4 Roles of Catalyst and Feed on Sediments Formation ........ 299
5.5 Effect of Hydroprocessing Reaction Conditions on
Sediment Formation ....................................... 305
5.5.1 Stages of Sediment Formation during
Hydrotreating ..................................... 306
5.5.2 Catalytic Reaction Temperature .................... 310
5.5.3 Thermal or Thermal Oxidation of Asphaltenes ....... 310
5.5.4 Pressure .......................................... 312
5.5.5 Effect of Feedstock or Diluents ................... 314
5.5.6 Role of Heteroatoms and Their Effect on Sediment
Formation ......................................... 315
5.6 Presumptions and Remedies for Sediment Formation ......... 318
5.7 Concluding Remarks ....................................... 321
References .................................................... 322
Chapter 6 Hydrocracking and Kinetics of Asphaltenes .......... 329
6.1 Introduction ............................................. 329
6.2 Effect of Reaction Conditions on Asphaltene
Hydrocracking ............................................ 330
6.2.1 Influence of Temperature .......................... 331
6.2.2 Influence of Solvent .............................. 334
6.2.3 Influence of Hydrogen Pressure .................... 337
6.2.4 Influence of Catalysts ............................ 339
6.2.5 Influence of Space Velocity ....................... 341
6.3 Reaction Pathways of Asphaltene Hydrocracking ............ 341
6.3.1 Noncatalytic Hydrocracking of Asphaltenes ......... 341
6.3.2 Catalytic Hydrocracking of Asphaltenes ............ 345
6.3.3 Role of Catalytic Sites on Asphaltenes
Hydrocracking ..................................... 349
6.4 Kinetic Modeling of Asphaltenes Hydrocracking ............ 354
6.4.1 Power Law Models .................................. 354
6.4.2 Discrete Models ................................... 358
6.4.3 Continuous Distribution Kinetics .................. 362
6.5 Concluding Remarks ....................................... 364
References .................................................... 365
Chapter 7 Fractionation of Heavy Crudes and Asphaltenes ...... 371
7.1 Introduction ............................................. 371
7.2 Distillation and Separation of Crude Oil ................. 372
7.2.1 SARA Fractionation of Crude Oil ................... 372
7.2.2 Supercritical Fluid Extraction and Fractionation
of Crude Oil ...................................... 373
7.2.3 Chromatographic Analysis for Crude Oil
Separation ........................................ 376
7.2.4 Separation of Porphyrins from Crude Oil ........... 378
7.2.5 Summary of Standards Methods for Distillation
and Fractionation of Petroleum .................... 381
7.2.5.1 Physical Distillation .................... 381
7.2.5.2 Chromatographic Methods .................. 383
7.3 Fractionation of Asphaltenes by Different Techniques ..... 384
7.3.1 Solvent Fractionation of Asphaltenes .............. 385
7.3.2 Fractionation of Asphaltenes by Size Exclusion
Chromatography (SEC) .............................. 392
7.4 Structure and Composition of Crude and Asphaltenes
after Fractionation ...................................... 397
7.4.1 Molecular Weight Distribution of Fractionated
Asphaltenes by MALDI .............................. 406
7.4.2 Microscopic Analysis of Fractionated
Asphaltenes ....................................... 406
7.4.2.1 Scanning Electron Microscope (SEM)
Analysis ................................. 409
7.4.2.2 ТЕМ Analysis ............................. 412
7.5 Concluding Remarks ....................................... 416
References .................................................... 416
Index ......................................................... 421
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