HETEROGENEOUS KINETIC MODELING OF THE CATALYTIC CONVERSION OF CYCLOPARAFFINS (Spine title: Kinetic...

HETEROGENEOUS KINETIC MODELING OF THE CATALYTIC CONVERSION OF CYCLOPARAFFINS

(Spine title: Kinetic Modeling of Catalytic Conversion of Cycloparaffins)

(Thesis format: Monograph)

by

Mustafa N. Al-Sabawi

Graduate Program in Engineering Science Department of Chemical & Biochemical Engineering

A thesis submitted in partial fulfillment of the requirements for the degree of

Doctor of Philosophy

The School of Graduate and Postdoctoral Studies The University of Western Ontario

London, Ontario, Canada

© Mustafa N. Al-Sabawi 2009

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THE UNIVERSITY OF WESTERN ONTARIO SCHOOL OF GRADUATE AND POSTDOCTORAL STUDIES

CERTIFICATE OF EXAMINATION

Supervisor

Dr. Hugo de Lasa

Supervisory Committee

Dr. Ajay Ray

Dr. Dimitre Karamanev

Examiners

Dr. Teh Ho

Dr. Hesham El-Naggar

Dr. Ajay Ray

Dr. Amarjeet Bassi

The thesis by

Mustafa Naiem Al-Sabawi

entitled:

Heterogeneous Kinetic Modeling of the Catalytic Conversion of Cycloparaffins

is accepted in partial fulfillment of the requirements for the degree of

Doctor of Philosophy

Date Chair of the Thesis Examination Board

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ABSTRACT

The limited availability of high value light hydrocarbon feedstocks along with the

rise in crude prices has resulted in the international recognition of the vast potential of

Canada's oil sands. With the recent expansion of Canadian bitumen production come,

however, many technical challenges, one of which is the significant presence of

aromatics and cycloparaffins in bitumen-derived feedstocks.

In addition to their negative environmental impact, aromatics limit fluid catalytic

cracking (FCC) feedstock conversion, decrease the yield and quality of valuable products

such as gasoline and middle distillates, increase levels of polyaromatic hydrocarbons

prone to form coke on the catalyst, and ultimately compromise the FCC unit

performance. Although cycloparaffins do not have such negative impacts, they are

precursors of aromatics as they frequently undergo hydrogen transfer reactions. However,

cycloparaffin cracking chemistry involves other competing reactions that are complex

and need much investigation.

This dissertation provides insights and understanding of the fundamentals of the

catalytic cracking of cycloparaffins using carefully selected model compounds such as

methylcyclohexane (MCH) and decalin. Thermal and catalytic cracking of these

cycloparaffins on FCC-type catalysts are carried out using the CREC Riser Simulator

under operating conditions similar to those of the industrial FCC units in terms of

temperature, reaction time, reactant partial pressure and catalyst-to-hydrocarbon ratio.

The crystallite size of the supported zeolites is varied between 0.4 and 0.9 microns, with

both activity and selectivity being monitored. Catalytic conversions ranged between 4 to

16 wt% for MCH and between 8 to 27 wt% for decalin. Reaction pathways of

cycloparaffins are determined, and these include ring-opening, protolytic cracking,

isomerization, hydrogen transfer and transalkylation. The yields and selectivities of over

60 and 140 products, formed during MCH and decalin catalytic conversions respectively,

are reported. Using these data, heterogeneous kinetic models accounting for

intracrystallite molecular transport, adsorption and thermal and catalytic cracking of both

cycloparaffin reactants are established. Results show that undesirable hydrogen transfer

reactions are more pronounced and selectively favoured against other reactions at lower

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reaction temperatures, while the desirable ring-opening and cracking reactions

predominate at the higher reaction temperatures. Moreover, results of the present work

show that while crystallite size may have an effect on the overall conversion in some

situations, there is a definite effect on the selectivity of products obtained during the

cracking of MCH and decalin and the cracking of MCH in a mixture with co-reactants

such as 1,3,5-triisopropylbenzene.

Keywords: cycloparaffins, naphthenes, fluid catalytic cracking, kinetic modeling, Y-zeolites, diffusion, adsorption, ring-opening, hydrogen transfer, catalyst selectivity

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"Qod' - there is no godSut He - the ^Ever-Living, the Self-suSsistent, 'Eternal Neither

slumber overtakes 'Kim nor sleep. "His is all that is in the heavens and ad that is on

earth. 'Who is there that couCdintercede with 'Him, unless it 6e by His Ceave? He djiows

aCC that Res open before his creation and aCC that is hidden from them, whereas they

cannot attain to aught of His knowledge save that which He witts [them to attain].

His eternal power overspreads the heavens and the earth, and their upholding wearies

Him not. JLndHe is the 9/Lost High, the Supreme (in glory)." (The Hoble Quran, Chapter

2, Verse 255)

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To the inquisitive mind ofMaryam, which keeps me on my toes

To the gentle spirit ofYusuf, whose depth I have yet to understand

And to all the other little ones that Sarrah wishes for

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ACKNOWLEDGEMENTS

First and foremost, all praise belongs to God, the Creator and Sustainer of all

things. I am most grateful to God Almighty, the Most Gracious and Most Merciful, for

giving me the strength and capability to complete this work successfully. I acknowledge

that it is only by His will and His mercy that this final product exists. I ask Him to accept

the effort and time put into this thesis for His sake only and to place all of my work on

the balance of good deeds on the Day of Judgment.

It is without doubt that I owe much gratitude to my advisor Dr. Hugo de Lasa for

providing me with the opportunity to work under his supervision on this project. You

were a great model of professionalism, and your guidance and support throughout the

years that I spent completing the Masters and Doctorate programs at UWO are greatly

appreciated and will never be forgotten.

I would like to also thank Mr. Jose Munoz for his assistance in the laboratory.

You were always around to lend me a helping hand, even if you were pre-occupied with

other more important things.

I am very appreciative for the financial support of the Natural Sciences and

Engineering Research Council of Canada (NSERC), which provided me with a Canada

Graduate Scholarship (CGS).

I would like to express my gratitude to the two most important people in the

world, my parents Naiem and Iman, for sacrificing their lives to provide me with

everything that I wished for. You have instilled in me the qualities that have brought me

to where I am today. May God Al-Mighty bless you for the time and effort that you

invested in me since the day you became parents.

"My Lord! Bestow on them your Mercy even as they cherished me in childhood. "

(The Noble Quran, Chapter 17, Verse 24)

Last but definitely not least, I would like to thank my wife Sarrah, God's special

gift to me. Your love, loyalty and sense of humour are what carry me forward through the

obstacles of life. You always put me ahead of yourself and inspire me to reach beyond

the stars.

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TABLE OF CONTENTS

Certificate of Examination ii

Abstract iii

Dedication vi

Acknowledgement vii

Table of Contents viii

List of Tables xiii

List of Figures xvi

List of Abbreviations, Symbols, & Nomenclature , xxiii

Chapter 1 - Introduction 1

Chapter 2 - Literature Review 4

2.1 Fluid Catalytic Cracking 4

2.2 History of the FCC Process 4

2.2.1 Evolution of FCC Units 5

2.2.2 Development of FCC Catalysts 8

2.3 FCC Process Description 9

2.3.1 Typical FCC Unit 9

2.3.1.1 The Riser Reactor - Vaporization and Reaction Zone 11

2.3.1.2 Gas-Solid Separation - Disengaging Zone and Cyclones 11

2.3.1.3 The Stripping Section - Hydrocarbon Recovery 12

2.3.1.4 Regenerator - Reactivation of Catalyst 12

2.3.2 FCC Catalyst 13

2.3.3 Feedstock 14

2.4 FCC Catalysts 15

2.4.1 Zeolite Component 16

2.4.1.1 Structure of Y-Zeolites 17

2.4.1.2 Zeolite Properties 22

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2.4.2 Matrix Component 22

2.4.3 Filler and Binder Components 23

2.5 FCC Feedstocks 24

2.5.1 Types of Oil Reserves 24

2.5.2 Bitumen-derived Crude Oil 25

2.5.2.1 Canadian Oil Sands 25

2.5.2.2 Bitumen Extraction Techniques 26

2.5.2.3 Upgrading Bitumen to Synthetic Crude Oil 27

2.6 FCCofCycloparaffins 30

2.6.1 Significance of Cycloparaffins 30

2.6.2 Previous Cycloparaffin Studies 31

2.6.2.1 Monocyclic Cycloparaffins 32

2.6.2.2 Bicyclic cycloparaffins 34

2.6.2.3 Drawbacks of Existing Cycloparaffin Studies 37

2.7 Fluid Catalytic Cracking Modeling 38

2.7.1 Role of Reactions in FCC Kinetic Modeling 38

2.7.1.1 Kinetic Models for Model Compounds 38

2.7.1.2 Kinetic Models for Gas Oil Feedstocks 39

2.7.1.3 Drawbacks of Existing Kinetic Modeling Studies 40

2.7.2 Other Phenomena in FCC Modeling 42

2.8 Diffusion in Porous Solids 44

2.8.1 Types of Diffusion 45

2.8.1.1 Bulk (Molecular) Diffusion 46

2.8.1.2 Knudsen Diffusion 46

2.8.1.3 Configurational Diffusion 47

2.8.2 Role of Diffusion in a Catalytic Chemical Reaction 49

2.8.3 Role of Diffusion in Fluid Catalytic Cracking 50

2.8.4 Measuring Diffusion in Zeolites 52

2.9 Adsorption in Porous Solids 54

2.9.1 Types of Adsorption 54

2.9.1.1 Physical Adsorption - Physisorption 54

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2.9.1.2 Chemical Adsorption - Chemisorption 55

2.9.2 Heat of Adsorption 56

2.9.3 Adsorption Isotherms 57

2.9.3.1 Henry's Law 58

2.9.3.2 The Langmuir Theory 59

2.9.3.3 Heterogeneity on the Surface and Other Isotherms 60

2.9.4 Role of Adsorption in FCC Catalysts 61

2.9.5 Measuring Adsorption in Zeolites 62

2.10 Literature Review Conclusions 65

Chapter 3 - Scope of Research 67

Chapter 4 - Experimental Apparatus and Procedure 70

4.1 Experimental System 70

4.1.1 CREC Riser Simulator 70

4.1.2 Gas Chromatography-Mass Spectrometry Unit 74

4.2 Cycloparaffin Model Compounds 74

4.3 FCC Catalysts 75

4.3.1 FCC Catalyst Preparation 75

4.3.2 FCC Catalyst Characterization 76

4.4 Experimental Conditions 78

4.4.1 Cycloparaffin Conversion Experiments 78

4.4.2 Mixture Experiments 79

4.5 Experimental Procedure 79

4.5.1 Catalyst Loading 79

4.5.2 Preparation for an Experiment 80

4.5.3 Performing an Experiment 81

4.5.4 Catalyst Regeneration 82

4.5.5 Post-Run Calculations 83

4.5.6 Shut-down of Riser Simulator 83

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Chapter 5 - Catalytic Cracking and Kinetic Modeling of a Monocyclic

Cycloparaffin 84

5.1 Introduction 84

5.2 MCH Cracking Results 85

5.2.1 Thermal Conversion of MCH 85

5.2.2 Catalytic Conversion of MCH 86

5.2.3 MCH Reaction Mechanisms 89

5.2.4 Hydrocarbon Product Yields 95

5.2.5 Catalyst Selectivity Results - CAT-LC vs. CAT-SC 105

5.3 Heterogeneous Kinetic Modeling of MCH Catalytic Conversion: Diffusion,

Adsorption and Reaction Phenomena 115

5.3.1 Proposed Heterogeneous Kinetic Model 115

5.3.2 Assessment of MCH Adsorption Parameters 125

5.3.3 Evaluation of Intrinsic Kinetic Parameters 132

5.3.3.1 Modeling Results - Thermal Cracking Parameters 132

5.3.3.2 Modeling Results - Catalytic Cracking Parameters 135

5.3.3.3 Model Simulation-Yield Plots 143

5.4 Conclusions 150

Chapter 6 - Catalytic Cracking and Kinetic Modeling of a Bicyclic

Cycloparaffin 152

6.1 Introduction 152

6.2 Decalin Cracking Results 153

6.2.1 Thermal Conversion of Decalin 153

6.2.2 Catalytic Conversion of Decalin 154

6.2.3 Decalin Reaction Mechanisms 157

6.2.4 Hydrocarbon Product Yields 165

6.2.5 Catalyst Selectivity Results - CAT-LC vs. CAT-SC 176

6.3 Heterogeneous Kinetic Modeling of Decalin Catalytic Conversion: Diffusion,

Adsorption and Reaction Phenomena 186

6.3.1 Proposed Heterogeneous Kinetic Model 186

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6.3.2 Assessment of Decalin Adsorption Parameters 193

6.3.3 Evaluation of Intrinsic Kinetic Parameters 197

6.3.3.1 Modeling Results - Thermal Cracking Parameters 197

6.3.3.2 Modeling Results - Catalytic Cracking Parameters 199

6.3.3.3 Model Simulation - Yield Plots 204

6.4 Conclusions 209

Chapter 7 - Investigation of Mass Transport Limitations on

Cycloparaffin Conversion 211

7.1 Introduction 211

7.2 Calculation of Conversion for Mixture Experiments 212

7.3 Influence of Co-reactant on Cycloparaffin Conversion 213

7.3.1 Thermal Cracking - Mixture versus Pure Compound Experiments 214

7.3.2 Catalytic Cracking - Mixture versus Pure Compound Experiments 215

7.4 Mixture Experiments - Catalyst Activity and Selectivity Results 220

7.4.1 1,3,5-TIPB Catalytic Conversion 220

7.4.2 MCH Catalytic Conversion 222

7.5 Conclusions 227

Chapter 8 - Conclusions and Recommendations 229

Bibliography 234

Appendix I - Assessment of Volume 246

Appendix II - Chromatogram Analysis 249

Appendix III - Experimental Results 253

Appendix IV - Calculation of Conversion in Mixture Experiments 297

Appendix V -MATLAB Program for Modeling 299

Curriculum Vitae 307

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LIST OF TABLES

Chapter 2

Table 2.1 - Properties of the most frequently used synthetic zeolites 18

Table 2.2 - Properties of bitumen and synthetic crude oil 30

Table 2.3 - Key criterion to discriminate between chemisorption and physisorption 56

Table 2.4 - Henry's law constants of linear and branched chains on various zeolites at300°K 64

Chapter 4

Table 4.1 - Properties cycloparaffin model compounds used in this study 75

Table 4.2 - Properties of the parent USY zeolites used in the preparation of FCC catalysts 76

Table 4.3 - Properties of the FCC catalysts with large and small crystallite sizes 77

Chapter 5

Table 5.1 - Product yields and selectivities obtained during MCH catalytic cracking over CAT-LC and CAT-SC at 550°C and 7 seconds 90

Table 5.2 - Heats of adsorption and adsorption constants for MCH over CAT-LC and CAT-SC 130

Table 5.3 - Adsorption constants for MCH conversion products participating in secondary reactions 131

Table 5.4 - Kinetic parameters for MCH thermal conversion 133

Table 5.5 - Cross-correlation matrix for non-linear regression of experimental data collected during thermal cracking of MCH 134

Table 5.6 - Intrinsic kinetic parameters for MCH catalytic conversion over CAT-LC 136

Table 5.7 - Intrinsic kinetic parameters for MCH catalytic conversion over

CAT-SC 137

Table 5.8 - Degrees of freedom for model parameter estimation 138

Table 5.9 - Cross-correlation between kinetic constants of the 8-parameter model (CAT-LC) 139

Table 5.10 - Cross-correlation between kinetic constants of the 8-parameter model (CAT-SC) 140

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Chapter 6

Table 6.1 - Product yields and selectivities obtained during decalin catalytic cracking over CAT-LC and CAT-SC at 550°C and 7 seconds 158

Table 6.2 - Heats of adsorption and adsorption constants for decalin over CAT-LC and CAT-SC 195

Table 6.3 - Kinetic parameters for decalin thermal conversion 198

Table 6.4 - Cross-correlation matrix for non-linear regression of experimental data collected during thermal cracking of decalin 198

Table 6.5 - Intrinsic kinetic parameters for decalin catalytic conversion over FCC Catalysts 200

Table 6.6 - Degrees of freedom for model parameter estimation 201

Table 6.7 - Cross-correlation between kinetic constants of the 8-parameter model (CAT-LC) 202

Table 6.8 - Cross-correlation between kinetic constants of the 8-parameter model (CAT-SC) 202

Appendices

Table A.l - Determination of the reactor volume 247

Table A.2 - Determination of the vacuum box (VB) volume 248

Table A.3 - Summary of the retention times of MCH and its products in GC unit 249

Table A.4 - Summary of the retention times of decalin and its products in GC unit 250

Table A.5 - Experimental runs for the catalytic cracking of MCH using CAT-LC 253

Table A.6 - Experimental runs for the catalytic cracking of MCH using CAT-SC 256

Table A.7 - Average MCH conversions obtained during thermal cracking 258

Table A.8 - Experimental runs for the catalytic cracking of decalin using CAT-LC 259

Table A.9 - Experimental runs for the catalytic cracking of decalin using CAT-SC 261

Table A. 10 - Average decalin conversions obtained during thermal cracking 264

Table A. 11 - Product yields and selectivities obtained during MCH catalytic cracking over CAT-LC at 450°C 265




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Table A. 16 - Product yields and selectivities obtained during MCH catalytic cracking over CAT-SC at 450°C 270




Table A.20 - Product yields and selectivities obtained during MCH catalytic cracking over CAT-SC at 550°C 274

Table A.21 - Product yields and selectivities obtained during decalin catalytic cracking over CAT-LC at 450°C 275





Table A.26 - Product yields and selectivities obtained during decalin catalytic cracking over CAT-SC at 450°C 280





Table A.31 - Average thermal and catalytic AP values and the corresponding MCH adsorption constants obtained for the range of reaction temperatures 295

Table A.32 - Average thermal and catalytic AP values and the corresponding decalin adsorption constants obtained for the range of reaction temperatures 296

Table A.3 3 - Coke production during MCH and decalin catalytic experiments 296

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LIST OF FIGURES

Chapter 2

Figure 2.1 - Flow plan of a typical refinery 5

Figure 2.2 - Orthoflow Resid FCC Converter 7

Figure 2.3 - Fluid Catalytic Cracking Unit - Exxon Model IV 7

Figure 2.4 - Flexicracking IIIR Unit 8

Figure 2.5 - A typical fluid catalytic cracking unit 10

Figure 2.6 - Conversion of heavy feedstocks into lighter fractions 14

Figure 2.7 - Configuration of a FCC catalyst pellet showing: the pellet, the dispersed

zeolite crystallites and the zeolite faujasite 16

Figure 2.8 - Composition of atypical FCC catalyst 17

Figure 2.9 - Primary tetrahedral building blocks of zeolites 18

Figure 2.10 - Sodalite cage structure 19

Figure 2.11 - Arrangement of the sodalite cage unit of Zeolite Y 20

Figure 2.12 - Faujasite elementary cell 20

Figure 2.13 - Structure of faujasite zeolite (type Y) 21

Figure 2.14 - Geometry of Y zeolites (faujasites) structure 21

Figure 2.15 - Breakdown of the total world oil reserves 24

Figure 2.16 - Physical and chemical steps involved in the heterogeneously catalyzed

reaction (A -> B) 44

Figure 2.17 - Effect of pore size on diffusivity 48

Figure 2.18 - Effect of pore size on activation energy of diffusion 48

Figure 2.19 - The six main types of gas physisorption isotherms, according to the IUPAC classification 58

Chapter 4

Figure 4.1 - Quarter section view of the CREC Riser Simulator 71

Figure 4.2 - Schematic diagram of the CREC Riser Simulator experimental set-up 71

Figure 4.3 - Typical pressure profile in the CREC Riser Simulator during a catalytic cracking run 73

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Chapter 5

Figure 5.1 - MCH conversion during thermal cracking in the CREC Riser Simulator at different temperatures and reaction time of 7 seconds 85

Figure 5.2 - Conversion of MCH over CAT-LC at different temperatures. Experiments were conducted at reaction times of 3, 5 and 7 seconds using a catalyst-to-oil ratio of 5 86

Figure 5.3 - Conversion of MCH over CAT-SC at different temperatures. Experiments were conducted at reaction times of 3, 5 and 7 seconds using a catalyst-to-oil ratio of 5 87

Figure 5.4 - MCH conversion obtained using CAT-LC versus CAT-SC. Experiments

were conducted using a catalyst-to-oil ratio of 5 88

Figure 5.5 - MCH ring opening/protolytic cracking mechanism 91

Figure 5.6 - MCH cracking via |3-scission mechanism 92

Figure 5.7 - Isomerization of MCH mechanism 92

Figure 5.8 - Conversion of MCH via dealkylation 92

Figure 5.9 - Conversion of MCH into toluene via hydrogen transfer 93

Figure 5.10 - Conversion of MCH via transalkylation 93

Figure 5.11 - General MCH reactions during FCC 94

Figure 5.12 - C2-C6 yield over MCH conversion using CAT-LC 95

Figure 5.13 - Heptene and heptane yields over MCH conversion using CAT-LC 96

Figure 5.14 - Proposed reaction route for the production of propene and isobutane 97

Figure 5.15 - Isomer yield over MCH conversion using CAT-LC 98

Figure 5.16 - Sequence in the formation of methylcyclohexene, methylcyclohexadiene and toluene via hydrogen transfer 99

Figure 5.17 - Methylcyclohexene yield over MCH conversion using CAT-LC 100

Figure 5.18 - Methylcyclohexadiene yield over MCH conversion using CAT-LC 100

Figure 5.19 - Toluene yield over MCH conversion using CAT-LC 101

Figure 5.20 - Benzene and xylene yields over MCH conversion using CAT-LC 102

Figure 5.21 - Cyclohexene yield over MCH conversion using CAT-LC 102

Figure 5.22 - Cg cycloparaffins yield over MCH conversion using CAT-LC 103

Figure 5.23 -Yield of Cs-C9 aromatics and total aromatics over MCH conversion using CAT-LC 104

Figure 5.24 - Simplified reaction scheme for the catalytic cracking of MCH based on observable products 105

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Figure 5.25 - Average selectivity of C2-C6 hydrocarbon products at various reaction temperatures for CAT-LC and CAT-SC. Reaction time = 7 seconds 106

Figure 5.26 - Average C2-C7 paraffin selectivity various reaction temperatures for CAT-LC and CAT-SC. Reaction time = 7 seconds 108

Figure 5.27 - Average C2-C7 olefin selectivity at various reaction temperatures for CAT-LC and CAT-SC. Reaction time = 7 seconds.... 109

Figure 5.28 - Average Cg cycloparaffin selectivity various reaction temperatures for CAT-LC and CAT-SC. Reaction time = 7 seconds 110

Figure 5.29 - Average selectivity of Cs and C9 aromatics at various reaction temperatures for CAT-LC and CAT-SC. Reaction time = 7 seconds 110

Figure 5.30 - Average cyclohexene selectivity various reaction temperatures for CAT-LC and CAT-SC. Reaction time = 7 seconds 112

Figure 5.31 - Average toluene selectivity various reaction temperatures for CAT-LC and CAT-SC. Reaction time = 5 seconds 112

Figure 5.32 - Average xylene selectivity various reaction temperatures for CAT-LC and CAT-SC. Reaction time = 7 seconds 113

Figure 5.33 - Average isomer selectivity various reaction temperatures for CAT-LC and CAT-SC. Reaction time = 7 seconds 114

Figure 5.34 - Proposed MCH catalytic conversion model 118

Figure 5.35 - Proposed MCH thermal conversion model 119

Figure 5.36 - Typical pressure profile in the CREC Riser Simulator during MCH thermal and catalytic cracking over Y-zeolite catalyst at 450°C andC/0 = 5 126

Figure 5.37 - Adsorption constants for MCH at different temperatures over CAT-LC and CAT-SC 129

Figure 5.38 - Arrhenius plot for MCH over CAT-LC and CAT-SC 130

Figure 5.39 - Residual distribution for non-linear regression of data obtained during MCH thermal cracking runs in the CREC Riser Simulator 134

Figure 5.40 - Residual distribution for non-linear regression of data obtained using CAT-LC (16-Parameter Model) 141

Figure 5.41 - Residual distribution for non-linear regression of data obtained using CAT-SC (16-Parameter Model) 141

Figure 5.42 - Yields of primary products obtained using CAT-LC at a temperature of 450°C and for a C/O =5 146

Figure 5.43 - Yields of secondary products (aromatics) obtained using CAT-LC at a temperature of 450°C and for a C/O -5 146

Figure 5.44 - Yields of primary products obtained using CAT-SC at a temperature of 450°C and for a C/O =5 147

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Figure 5.45 - Yields of secondary products (aromatics) obtained using CAT-SC at a temperature of 450°C and for a C/O =5 147

Figure 5.46 - Yields of primary products obtained using CAT-LC at a temperature of 550°C and for a C/O =5 148

Figure 5.47 - Yields of secondary products (aromatics) obtained using CAT-LC at a temperature of 550°C and for a C/O =5 148

Figure 5.48 - Yields of primary products obtained using CAT-SC at a temperature of 550°C and for a C/O =5 149

Figure 5.49 - Yields of secondary products (aromatics) obtained using CAT-SC at a temperature of 550°C and for a C/O =5 149

Chapter 6

Figure 6.1 - Decalin conversion during thermal cracking at different temperatures and reaction time of 7 seconds 153

Figure 6.2 - Decalin conversion over CAT-LC at different temperatures. Experiments were conducted at reaction times of 3, 5 and 7 seconds using a catalyst-to-oil ratio of 5 154

Figure 6.3 - Decalin conversion over CAT-SC at different temperatures. Experiments were conducted at reaction times of 3, 5 and 7 seconds using a catalyst-to-oil ratio of 5 155

Figure 6.4 - Decalin conversion obtained using CAT-LC versus CAT-SC. Experiments were conducted using a catalyst-to-oil ratio of 5 156

Figure 6.5 - RON and ROA compounds obtained via decalin ring opening 159

Figure 6.6 - Decalin ring opening/protolytic cracking mechanism 159

Figure 6.7 - p-scission of the Cio carbenium ion and ensuing butyl cation isomerization steps 160

Figure 6.8 - Protolytic cracking of the alkyl substituent from alkylbenzene 161

Figure 6.9 - Isomerization of decalin via ring contraction 162

Figure 6.10 - Conversion of decalin via transalkylation 163

Figure 6.11 - Conversion of decalin via hydrogen transfer 164

Figure 6.12 - Yield of aliphatic olefins over decalin conversion using CAT-LC 166

Figure 6.13 - Yield of aliphatic paraffins over decalin conversion using CAT-LC 167

Figure 6.14 - Total yield of C5-C7 naphthenes and aromatics, in the cracking products fraction, over decalin conversion using CAT-LC 167

Figure 6.15 - Yield of Cio ring opening products over decalin conversion using CAT-LC 169

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Figure 6.16 - Yield of Cio naphtheno-aromatics over decalin conversion using

CAT-LC 170

Figure 6.17 - Yield of naphthalene over decalin conversion using CAT-LC 171

Figure 6.18 - Yield of bicyclical aromatics having more carbons than the feed over decalin conversion using CAT-LC 171

Figure 6.19 - Yield of naphthenes having more carbons than the feed over decalin conversion using CAT-LC 172

Figure 6.20 - Yield of all products having more carbons than the feed over decalin

conversion using CAT-LC 173

Figure 6.21 - Isomer yield over MCH conversion using CAT-LC 174

Figure 6.22 - Reaction scheme for the catalytic cracking of decalin using USY zeolite catalysts 175

Figure 6.23 - Average selectivity of cracking products at various reaction temperatures for CAT-LC and CAT-SC. Reaction time = 7 seconds 177

Figure 6.24 - Average selectivity of Cio ring opening products at various reaction temperatures for CAT-LC and CAT-SC. Reaction time = 7 seconds 178

Figure 6.25 - Average selectivity of C2-C7 paraffins and isoparaffins at various reaction temperatures for CAT-LC and CAT-SC. Reaction time = 7 seconds 179

Figure 6.26 - Average selectivity of C2-C7 olefins at various reaction temperatures for CAT-LC and CAT-SC. Reaction time = 7 seconds 180

Figure 6.27 - Average selectivity of Cio naphtheno-aromatic products at various reaction temperatures for CAT-LC and CAT-SC. Reaction time = 7 seconds 181

Figure 6.28 - Average selectivity of naphthalene at various reaction temperatures for CAT-LC and CAT-SC. Reaction time = 5 seconds 182

Figure 6.29 - Average selectivity of large C11-C12 aromatic products at various reaction temperatures for CAT-LC and CAT-SC. Reaction time = 7 seconds 183

Figure 6.30 - Average selectivity of large C11-C12 cycloparaffins products at various reaction temperatures for CAT-LC and CAT-SC. Reaction time = 7 seconds 184

Figure 6.31 - Average selectivity isomer products at various reaction temperatures for

CAT-LC and CAT-SC. Reaction time = 7 seconds 185

Figure 6.32 - Proposed decalin catalytic conversion model 187

Figure 6.33 - Proposed decalin thermal conversion model 189

Figure 6.34 - Adsorption constants for decalin at different temperatures over CAT-LC and CAT-SC 194

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Figure 6.35 - Arrhenius plot for decalin over CAT-LC and CAT-SC 195

Figure 6.36 - Adsorption constants for various model compounds on CAT-LC at450°C 196

Figure 6.37 - Residual distribution for non-linear regression of data obtained during decalin thermal cracking runs in the CREC Riser Simulator 199

Figure 6.38 - Residual distribution for non-linear regression of data obtained using CAT-LC 203

Figure 6.39 - Residual distribution for non-linear regression of data obtained using CAT-SC 203

Figure 6.40 - Yields of products obtained using CAT-LC at a temperature of 450°C and for a C/O =5 205

Figure 6.41 - Yields of products obtained using CAT-SC at a temperature of 450°C and for a C/O =5 206

Figure 6.42 - Yields of products obtained using CAT-LC at a temperature of 550°C and for a C/O =5 207

Figure 6.43 - Yields of products obtained using CAT-SC at a temperature of 550°C and for a C/O =5 207

Chapter 7

Figure 7.1 - Comparing MCH conversions obtained during MCH/1,3,5-TIPB mixture thermal runs versus pure MCH thermal experiments at various reaction conditions 214

Figure 7.2 - Comparing 1,3,5-TIPB conversions obtained during MCH/1,3,5-TIPB mixture thermal runs versus pure 1,3,5-TIPB thermal experiments at various reaction conditions 216

Figure 7.3 - Toluene yields obtained during MCH/1,3,5-TIPB mixture thermal runs and pure MCH thermal experiments at various reaction temperatures 216

Figure 7.4 - Comparing MCH conversions obtained during MCH/1,3,5-TIPB mixture catalytic runs versus pure MCH catalytic experiments for CAT-LC and CAT-SC 217

Figure 7.5 - C4-C5 product yields obtained during MCH/1,3,5-TIPB mixture catalytic runs and pure MCH catalytic experiments using CAT-LC at various reaction temperatures. Reaction time = 7 seconds 219

Figure 7.6 - Toluene yields obtained during MCH/1,3,5-TIPB mixture thermal runs and pure MCH thermal experiments using CAT-SC at various reaction temperatures. Reaction time = 7 seconds 219

Figure 7.7 - Comparing 1,3,5-TIPB conversions obtained using CAT-LC and CAT-SC during MCH/1,3,5-TIPB mixture experiments under various temperatures 221

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Figure 7.8 - Comparing MCH conversions obtained using CAT-LC and CAT-SC during MCH/1,3,5-TIPB mixture experiments under various temperatures 223

Figure 7.9 - Comparing the difference in MCH conversion (AXMCH) obtained during MCH/1,3,5-TIPB mixture runs versus pure MCH runs using CAT-LC and CAT-SC at various reaction temperatures 224

Figure 7.10 - Toluene selectivity obtained during (a) MCH/1,3,5-TIPB mixture runs (left) and (b) pure MCH runs (right), using CAT-LC and CAT-SC at reaction time = 5 seconds 226

Figure 7.11 - Toluene selectivity obtained during (a) MCH/1,3,5-TIPB mixture runs (left) and (b) pure MCH runs (right), using CAT-LC and CAT-SC at reaction time = 3 seconds 226

Appendices

Figure A.l - Pressure profile recorded during thermal conversion of MCH at 475°C and 7 seconds 285

Figure A.2 - Pressure profile recorded during catalytic conversion of MCH at 550°C and 3 seconds using CAT-LC 285

Figure A.3 - Pressure profile recorded during thermal conversion of MCH at 550°C and 5 seconds 290

Figure A.4 - Pressure profile recorded during catalytic conversion of MCH at 550°C and 7 seconds 290

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LIST OF ABBREVIATIONS, SYMBOLS & NOMENCLATURE

Nomenclature

At Area of species i in chromatogram

6, Adsorption coefficient of species /

Ci Concentration of lump i in the vapor phase (mol/m )

Ciex Concentration of species i outside the US Y crystallite (mol/m )

Clin Concentration of species i within pore network of the US Y crystallite (mol/m3)

c dp

»eff

DK

A>

ED

E>

ETi

G

H

K

Mass concentration of species i in the vapour phase (kg/m3)

Catalyst pore diameter (m"1)

Effective diffusivity (m2/s)

Knudsen diffusion (m2/s)

Pre-exponential factor for diffusion (m /s)

Activation energy for diffusion (kJ/mol)

Intrinsic activation energy catalytic reaction / (kJ/mol)

Intrinsic activation energy for thermal reaction i (kJ/mol)

Gibbs Free Energy (kJ)

Enthalpy (kJ) 1 ->

Intrinsic kinetic constant for catalytic reaction i (s") or [m /(mol-s)] or [l/(mol-s)]

ki0 Pre-exponential factor for catalytic reaction i (s"1) or [m3/(mol-s)] or

[l/(mol-s)]

kTi Intrinsic kinetic constant for thermal reaction i (s"1)

kTi0 Pre-exponential factor for thermal reaction i (s"1)

Kt Adsorption constant for species i [m3/(kg of catalyst)]

Ki0 Adsorption pre-exponential factor [m3/(kg of catalyst)]

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HETEROGENEOUS KINETIC MODELING OF THE CATALYTIC CONVERSION OF CYCLOPARAFFINS (Spine title: Kinetic...

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