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Activity and Selectivity Studies Silica Supported Fischer Tropsch Catalysts - 1982

Kym Brian Arcuri

Northwestern University

Table of Contents 554kb

Section 1
1249kb		 List of Figures xii
List of Tables xxviii

1

 The Fischer Tropsch Synthesis 1
  1.1  Historical Overview 1
1.2  Primary FT Reactions and Secondary Complicating Reactions 2
Section 2
1086kb

2

 The Product Distribution and Reaction Mechanism 3
 

2.1

 The Product Distribution 3
  2.1.1 Hydrocarbon Products 3
2.1.2 Oxygenated Products 5

2.2

 Reaction Mechanisms 6
  2.2.1 The Carbidic Intermediate 8
2.2.2 The Oxygen Containing Intermediate 13
2.2.3  Carbidic Initiation/CO Insertion 16
Section 3
1497kb

2.3

 Surface Studies on FT Catalysts 17
  2.3.1 IR Spectroscopy 17
2.3.2 Electron Spectroscopies 19

2.4

 Hydrogenation/Isomerization Reaction Mechanisms 20

3

 Experimental Methods and Catalyst Characterization 24
  3.1  Catalyst Preparation 24
3.2 Characterization Methods and Results 25
  3.2.1 Mossbauer Spectroscopy; Theory and Results 25
  3.2.1.1

Theory

 25
3.2.1.2

Experimental

 33
Section 4
1257kb		 3.2.2 Catalyst Characterization 34
  3.2.2.1 Fe Catalyst 34
3.2.2.2 FeCo Catalyst 38
3.2.2.3 Co Catalyst 41

3.2.3

 Catalytic Surface Area Measurements 41

3.3

 Reactor and Analytical Equipment 43
  3.3.1 The Differential Flow Reactor 43
3.3.2 Feed Mixtures 46
Section 5
939kb		 3.3.3 Gas Chromatograph Calibration Procedure 47
3.3.4 Gas Chromatographs Employed 48
3.3.5 Rate Data Analysis 53
Section 6
517kb

4

 Reaction Studies Using CO/H2 Mixtures 56
 

4.1

 CO Activity Studies 56
  4.1.1 Fe Catalyst 57
4.1.2 Co Catalyst 60
4.1.3 FeCo Catalyst 61
Section 7
524kb		 4.1.4 Comparison of Rate Data with Proposed Kinetic Expressions 65
4.1.5 Methane Differential Selectivity 66
4.1.6 Relative Methanol Activities 72
Section 8
630kb		 4.1.7 Activity Maintenance Studies 74

4.2

 Water Gas Shift Activity 78
  4.2.1 Effects of Pressure and Feed Composition 78
4.2.2 Shift Equilibrium and Rate Models 80
Section 9
512kb		 4.2.3 Effects of Water Vapor 86

4.3

 Low Molecular Weight Product Yields 88
  4.3.1 Olefin Yields for the Fe Catalyst with the 1/3 CO/H2 Feed 89
4.3.2 Olefin Yields for the Fe Catalyst with the 1/3 CO/H2 Feed 93
Section 10
627kb		 4.3.3 Olefin Yields for the Co Catalyst with the 1/3 CO/H2 Feed 96
4.3.4 Comparison of the C2 and C3 Yields and Olefin Selectivities for all three Catalysts 96
4.3.5 Methane Yields using the 1/3 CO/H2 Feed 101
Section 11
779kb		 4.3.6 Olefin Yields and Selectivities using the 1/1 CO/H2 Feed 108
Section 12
775kb		 4.3.7 Methane Yields using the 1/1 CO H2 Feed 124

4.4

 Steady State Product Distributions 129
  4.4.1 Overall Product Distributions 129
Section 13
736kb		 4.4.2 Shifts in the Product Distribution due to conversion and pressure 140

4.5

  Schulz Flory Parameterization 153
Section 14
866kb		   4.5.1 Fe Catalyst 155
4.5.2 Co Catalyst 159
4.5.3 FeCo Catalyst 159
4.5.4 Growth Probability dependence on pressure and feed rates 162
4.5.5 C1 Product Yields 167
Section 15
887kb

4.6

 Transient Studies on a Fully Carburized Iron Catalyst 172
  4.6.4 1/3 CO/H2 Feed 184
Section 16
682kb		 4.6.5 Production of CO2 and CH3OH through a Common Intermediate 188
  4.6.5.1 Transient Response of Oxygenated Products 188
4.6.5.2 Proposed Shift Reaction Mechanisms 191
4.6.5.3  Proposed Mechanisms for CH3OH Production 192

5

 Synthesis Studies in Olefin Enhanced Feeds 194
 

5.1

 Methane Activities 195
  5.1.1 Fe Catalyst 195
5.1.2 FeCo Catalyst 197
5.1.3 Co Catalyst 197
5.1.4 Discussion on 1-Pentene Hydrocracking 200
Section 17
1095kb

5.2

 Product Yields and Selectivities for Olefin Containing Feeds 201
  5.2.1 Hydrocarbon Yields with the Ethylene containing Feed 201
5.2.2 Hydrocarbon Yields with the 1-Pentene containing Feed 212
  5.2.2.1 Fe Catalyst 213
5.2.2.2 FeCo Catalyst 213
Section 18
1139kb		 5.2.2.3 Co Catalyst 219
5.2.2.4 Hydrocracking over the Co Catalyst 222

5.2.3

 Methanol and Carbon Dioxide Yields 224

5.3

 Schultz Flory Parameterization 227
  5.3.1 Fe Catalyst 228
5.3.2 Co Catalyst 230
Section 19
953kb		 5.3.3 FeCo Catalyst 238
5.3.4 Mechanistic Implications 238

5.4

 Selectivity Studies and Secondary Reactions 248
 

5.4.1

 Olefin/Paraffin Selectivities Using the Ethylene Enhanced Feed 248
  5.4.1.1 Fe Catalyst 248
5.4.1.2 Co Catalyst 250
Section 20
767kb		 5.4.1.3 FeCo Catalyst 254
5.4.2 Hydrogenation of Feed Gas Ethylene 258
Section 21
1006kb		 5.4.3 Proposed Reaction Network for the Primary and Secondary FT Reactions 266
5.4.4 Olefin/Paraffin Selectivities in the 1-Pentene Enhanced Feed 276
Section 22
763kb		 5.4.5 Secondary Reactions Involving 1-Pentene 284
5.4.6 Proposed Reaction Network for the C5 Products 291
Section 23
997kb

6 

 Review of Results and Conclusions 298
 

6.1

  Summary of Observed General Behavior of the FT Synthesis 298
  6.1.1 Result Summary of Chapter 4 298
6.1.2 Result Summary of Chapter 5 300

6.2

 Summary of the Observed Kinetic Differences Between the Alloy and Pure Component Catalysts 302
  6.2.1 Result Summary of Chapter 4 302
6.2.2 Result Summary of Chapter 5 303

6.3

 Generalized Reaction Sequence Involving Multiple Surface Intermediates 304

7

 Some Considerations for Future FT Research 306
Section 24
565kb		 Appendix I: GC Calibration Mixtures 315
Appendix II: Reaction Rate Analysis 318
Appendix III: Boudouard Reaction Equilibrium Constant 324
Appendix IV: Adsorption Calculations Under FT Conditions 325
Section 25
546kb		 Appendix V: Various Product Yields Using the Olefin Containing Feeds 327
Appendix VI: Methane Activities for the Co catalyst with various CO/H2 Feeds 336
List of References 337
Vita 334