Chapter 1. Introduction ......................................... 1
1.1. Motivation ................................................. 1
1.2. Background ................................................. 2
1.3. Modeling Approaches ........................................ 4
1.4. Molecule-based Kinetic Modeling Strategy ................... 5
1.5. The Premise ................................................ 6
References ...................................................... 7
Part I Methods
Chapter 2. Molecular Structure and Composition Modeling
of Complex Feedstocks ............................... 11
2.1. Introduction .............................................. 11
2.2. Analytical Characterization of Complex Feedstocks ......... 13
2.3. Molecular Structure Modeling: A Stochastic Approach ....... 14
2.3.1. Probability Density Functions (PDFs) ............... 15
2.3.1.1. PDFs Used to Describe Complex Mixtures .... 16
2.3.1.2. Molecular Structural Attributes ........... 17
2.3.1.3. Appropriate PDF Forms ..................... 18
2.3.1.4. Discretization, Truncation, and
Renormalization ........................... 19
2.3.1.5. Conditional Probability ................... 21
2.3.2. Monte Carlo Construction ........................... 21
2.3.2.1. Monte Carlo Sampling Protocol ............. 21
2.3.2.2. Optimal Representation of a Complex
Feedstock ................................. 22
2.3.2.3. Sample Size ............................... 24
2.3.3. Quadrature Molecular Sampling ...................... 25
2.3.3.1. Quadrature Sampling Protocol .............. 25
2.3.3.2. Fine-Tuning the Quadrature Molecular
Representation ............................ 27
2.4. A Case Study: Light Gas Oil ............................... 27
2.5. Discussions and Summary ................................... 31
References ................................................ 32
Chapter 3. Automated Reaction Network Construction of
Complex Process Chemistries ......................... 35
3.1. Introduction .............................................. 35
3.2. Reaction Network Building and Control Techniques .......... 39
3.2.1. Preprocessing Methodologies ........................ 39
3.2.1.1. Rule-Based Model Building ................. 39
3.2.1.2. Seeding and Deseeding ..................... 42
3.2.2. In Situ Processing Methodologies ................... 45
3.2.2.1. Generalized Isomorphism Algorithm as
an On-the-Fly Lumping Tool ................ 45
3.2.2.2. Stochastic Rules for Reaction Site
Sampling .................................. 47
3.2.3. Postprocessing Methodologies ....................... 48
3.2.3.1. Generalized Isomorphism-Based Late
Lumping ................................... 48
3.2.3.2. Species-Based and Reaction-Based
Model Reduction ........................... 48
3.3. Properties of Reaction Networks ........................... 51
3.3.1. Properties of Species .............................. 51
3.3.2. Properties of Reactions ............................ 53
3.3.3. Characterization of the Reaction Network ........... 54
3.4. Summary and Conclusions ................................... 54
References ................................................ 55
Chapter 4. Organizing Kinetic Model Parameters ................. 57
4.1. Introduction .............................................. 57
4.2. Rate Laws For Complex Reaction Networks ................... 58
4.2.1. Kinetic Rate Laws at the Pathways Level ............ 59
4.2.2. Kinetic Rate Laws at the Mechanistic Level ......... 63
4.3. Overview of Linear Free Energy Relationships .............. 65
4.4. Representative Results and Summary of LFERS
for Catalytic Hydrocracking ............................... 70
4.5. Summary and Conclusions ................................... 75
References ................................................ 75
Chapter 5. Matching the Equation Solver to the Kinetic
Model Type .......................................... 79
5.1. Introduction .............................................. 79
5.2. Mathematical Background ................................... 80
5.2.1. Underlying Numerical Methods for Solving
DKM Systems ........................................ 80
5.2.2. Stiffness in DKM Systems ........................... 81
5.2.3. Sparseness in DKM Systems .......................... 82
5.3. Experiments ............................................... 83
5.3.1. Candidate DKMs ..................................... 83
5.3.2. Candidate Solvers .................................. 83
5.3.3. Experiment Setup ................................... 85
5.4. Results and Discussion .................................... 85
5.4.1. Pathways-Level DKM ................................. 86
5.4.2. Mechanistic-Level DKM .............................. 87
5.4.3. DKM Model Solving Guidelines ....................... 88
5.5. Summary and Conclusions ................................... 89
References ................................................ 89
Chapter 6. Integration of Detailed Kinetic Modeling Tools
and Model Delivery Technology ....................... 91
6.1. Introduction .............................................. 91
6.2. Integration of Detailed Kinetic Modeling Tools ............ 92
6.2.1. The Integrated Kinetic Modeler's Toolbox ........... 92
6.2.1.1. The Molecule Generator (MolGen) ........... 92
6.2.1.2. The Reaction Network Generator (NetGen) ... 94
6.2.1.3. The Model Equation Generator (EqnGen) ..... 95
6.2.1.4. The Model Solution Generator (SolGen) ..... 95
6.2.2. Parameter Optimization and Property Estimation ..... 96
6.2.2.1. The Parameter Optimization (ParOpt)
Framework ................................. 96
6.2.2.2. Optimization Algorithms ................... 96
6.2.2.3. The Objective Function .................... 98
6.2.2.4. Property Estimation of Mixtures ........... 98
6.2.2.5. The End-to-End Optimization Strategy ...... 99
6.2.3. Conclusions ........................................ 99
6.3. KMT Development and Model Delivery ....................... 100
6.3.1. Platform and Porting .............................. 100
6.3.2. Data Issues ....................................... 102
6.3.3. User Interface Issues ............................. 102
6.3.4. Documentation Issues .............................. 103
6.3.5. Lessons Learned ................................... 103
6.4. Summary .................................................. 103
References .................................................... 104
Part II Applications
Chapter 7. Molecule-Based Kinetic Modeling of Naphtha
Reforming .......................................... 109
7.1. Introduction ............................................. 109
7.2. Modeling Approach ........................................ 110
7.3. Model Development ........................................ 111
7.3.1. Dehydrocyclization ................................ 112
7.3.2. Hydrocracking ..................................... 114
7.3.3. Hydrogenolysis .................................... 115
7.3.4. Paraffin Isomerization ............................ 115
7.3.5. Naphthene Isomerization ........................... 116
7.3.6. Dehydrogenation (Aromatization) ................... 116
7.3.7. Dealkylation ...................................... 116
7.3.8. Coking ............................................ 117
7.4. Automated Model Building ................................. 117
7.5. The Model For C14 Naphtha Reforming ...................... 118
7.6. Model Validation ......................................... 119
7.7. Summary and Conclusions .................................. 121
References .................................................... 121
Chapter 8. Mechanistic Kinetic Modeling of Heavy Paraffin
Hydrocracking ...................................... 123
8.1. Introduction ............................................. 123
8.2. Mechanistic Modeling Approach ............................ 123
8.3. Model Development ........................................ 126
8.3.1. Reaction Mechanism ................................ 126
8.3.2. Reaction Families ................................. 127
8.3.2.1. Dehydrogenation and Hydrogenation ........ 127
8.3.2.2. Protonation and Deprotonation ............ 127
8.3.2.3. Hydride and Methyl Shift ................. 128
8.3.2.4. PCP Isomerization ........................ 129
8.3.2.5. β-Scission .............................. 130
8.3.2.6. Inhibition Reaction ...................... 130
8.3.3. Automated Model Building .......................... 131
8.3.4. Kinetics: Quantitative Structure Reactivity
Correlations ...................................... 133
8.3.5. The C16 Paraffin Hydrocracking Model at the
Mechanistic Level ................................. 134
8.4. Model Results and Validation ............................. 135
8.5. Extension to C80 Model ................................... 137
8.6. Summary and Conclusions .................................. 138
References ............................................... 139
Chapter 9. Molecule-Based Kinetic Modeling of Naphtha
Hydrotreating ...................................... 141
9.1. Introduction ............................................. 141
9.2. Modeling Approach ........................................ 142
9.3. Model Development ........................................ 144
9.3.1. Reaction Families ................................. 144
9.3.1.1. Reactions of Sulfur Compounds:
Desulfurization and Saturation ........... 145
9.3.1.2. Olefin Hydrogenation ..................... 151
9.3.1.3. Aromatic Saturation ...................... 151
9.3.1.4. Denitrogenation .......................... 151
9.3.2. Reaction Kinetics ................................. 152
9.3.3. Automated Model Building .......................... 153
9.4. Results and Discussion ................................... 154
9.4.1. The Naphtha Hydrotreating Model ................... 154
9.4.2. Model Optimization and Validation ................. 154
9.5. Summary and Conclusions .................................. 155
References ............................................... 157
Chapter 10.Automated Kinetic Modeling of Gas Oil
Hydroprocessing .................................... 159
10.1.Introduction ............................................. 159
10.2.Modeling Approach ........................................ 160
10.3.Model Development ........................................ 166
10.3.1.Feedstock Characterization and Construction ....... 166
10.3.2.Reaction Families ................................. 167
10.3.2.1.Reactions of Aromatics and
Hydroaromatics ........................... 168
10.3.2.2.Reactions of Naphthenes .................. 172
10.3.2.3.Reactions of Paraffins ................... 173
10.3.2.4.Reactions of Olefins ..................... 173
10.3.2.5.Reactions of Sulfur Compounds ............ 173
10.3.2.6.Reactions of Nitrogen Compounds .......... 174
10.3.3.Kinetics: LHHW Formalism .......................... 175
10.3.4.Automated Model Building .......................... 177
10.4.Results and Discussion ................................... 178
10.5.Summary and Conclusions .................................. 179
References ............................................... 181
Chapter 11.Molecular Modeling of Fluid Catalytic Cracking ..... 183
11.1.Introduction ............................................. 183
11.2.Model Pruning Strategies For Mechanistic Modeling ........ 184
11.2.1.Mechanistic Modeling .............................. 184
11.2.2.Rules Based Reaction Modeling ..................... 184
11.2.2.1.Reaction Rules ........................... 184
11.2.2.2.Stochastic Rules ......................... 186
11.3.Kinetics ................................................. 191
11.3.1.Intrinsic Kinetics ................................ 191
11.3.2.Coking Kinetics ................................... 192
11.4.Model Diagnostics and Results ............................ 193
11.5.Mechanistic Model Learning as a Basis for Pathways
Level Modeling ........................................... 194
11.6.Pathways Modeling ........................................ 194
11.6.1.Pathways Model Development Approach ............... 195
11.6.2.Pathways Level Reaction Rules ..................... 196
11.6.2.1.Cracking Reactions ....................... 196
11.6.2.2.Isomerization Reactions .................. 197
11.6.2.3.Methyl Shift Reactions ................... 198
11.6.2.4.Hydrogenation and Dehydrogenation
Reactions ................................ 198
11.6.2.5.Aromatization ............................ 198
11.6.3.Coking Kinetics ................................... 198
11.6.4.Gas Oil Composition ............................... 199
11.6.5.Model Diagnostics and Results ..................... 199
11.7.Summary and Conclusions .................................. 203
References ............................................... 203
Chapter 12.Automated Kinetic Modeling of Naphtha Pyrolysis .... 205
12.1.Introduction ............................................. 205
12.2.Current Approach to Model Building ....................... 206
12.3.Pyrolysis Model Development .............................. 207
12.3.1.Reaction Rules .................................... 208
12.3.1.1.Initiation ............................... 208
12.3.1.2.Hydrogen Abstraction ..................... 208
12.3.1.3.P-Scission ............................... 209
12.3.1.4.Radical Addition to Olefins .............. 210
12.3.1.5.Diels-Alder Reaction ..................... 210
12.3.1.6.Termination Reactions .................... 211
12.4.Contribution of Reaction Families ........................ 211
12.5.Reaction Network Diagnostics ............................. 214
12.6.Parameter Estimation ..................................... 215
12.7.Summary and Conclusions .................................. 216
References .................................................... 218
Chapter 13.Summary and Conclusions ............................ 221
13.1.Summary .................................................. 221
13.1.1.Molecular Structure and Composition Modeling
of Complex Feedstocks ............................. 222
13.1.2.Automated Reaction Network Building of Complex
Process Chemistries ............................... 223
13.1.3.Kinetic Rate Organization and Evaluation
of Complex Process Chemistries .................... 224
13.1.4.Model Solving Techniques for Detailed Kinetic
Models ............................................ 224
13.1.5.Integration of Detailed Kinetic Modeling Tools
and Model Delivery Technology ..................... 225
13.1.6.Molecule-Based Kinetic Modeling of Naphtha
Reforming ......................................... 226
13.1.7.Mechanistic Kinetic Modeling of Heavy Paraffin
Hydrocracking ..................................... 226
13.1.8.Molecule-Based Kinetic Modeling of Naphtha
Hydrotreating ..................................... 227
13.1.9.Automated Kinetic Modeling of Gas Oil
Hydroprocessing ................................... 228
13.1.10.Molecular Modeling of Fluid Catalytic Cracking ... 229
13.1.11.Automated Kinetic Modeling of Naphtha
Pyrolysis ......................................... 229
13.2.Conclusions .............................................. 229
Index ......................................................... 231
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