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ARCHIVES of 2I:Cf Ncy THE KINETICS OF HYDRODEMETALLATION OF METALLOPORPHYRINS BY CHI-WEN HUNG B. Ch. E., National Taiwan University (1974) Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology August, 1979 -I signature of Author Department of Chemical Engineering August, 1979 Certified by James Wei, Thesis Supervisor Accepted by G. C. Williams, Chairman, Departmental Committee on Graduate Thesis ARCHIVES OF 2i:cf ncY LIBRARIES THE KINETICS OF HYDRODEMETALLATION OF METALLOPORPHYRINS BY CHI-WEN HUNG Submitted to the Department of Chemical Engineering on August 3 , 1979 in partial fulfillment of the requirements for the Degree of Doctor of Philosophy. ABSTRACT The kinetics of hydrodemetallation of nickel etioporphyrin I (Ni-Etio), nickel tetraphenylporphine (Ni-TPP), and vanadyl etioporphyrin I (VO-Etio) have been studied in batch autoclave experiments, with white oils as solvents, and CoO -MoO 3 /Al 2 03 as catalyst without presulfiding. The effects of hydrogen pressure up to 12-500 KPa and temperature between 287-357 C were studied. Up to 90% metal removal, the data can be described by fractional order kinetics. The activation energy is from 27-37 kcal/g mole, and the hydrogen pressure dependence is from 1.2-2.2 order. Vanadium removal tends to have larger activation energy and smaller hydrogen pressure dependence. A few runs on mixed vanadyl and nickel etioporphyrins showed that while the presence of vanadyl compounds will suppress the nickel removal reaction, the reverse is less significant. Few runs on free base etio- porphyrin and tetraphenylporphine show that free base porphyrins quickly disappear in the autoclave. Catalyst with different propotion of cobalt and molybdenum have been prepared to catalyze nickel etioporphyrin as reactants. The result .shows that order of impregnation has no effect on hydrodemetallation activity, and MoO 3/Al 2 0 3 catalyst is more active than CoO/Al 2 0 3 catalyst. Thesis Supervisor: James Wei Professor and Department Head of Chemical Engineering ACKNOW:EDGEMENTS I would like to express my appreciation and gratitude to my advisor, Dr. James Wei, for the guidance and support given to me over these years. The useful discussion with Drs. Putnam, Satterfield, and Vayenas of the M.I.T. Chemical Engineering Department, and Dr. Peter Hambright of Howard University are greatly appreciated. My colleague, Rakesh Agrawal, has been of invaluable help to me. I would also like to thank my friends for their helping hands and advice regarding my research. Among them are Kelvin Chew, Joe Cocchetto, Selahattin Gultekin, George Huff Jr., Jen-Jiang Lee, and Cherng-Chiao Wu. This work is dedicated to my parents, Dr. and Mrs. Tsu-Pei Hung, and especially to my wife, Shu-Fang, for her assistance in typing the manuscript and for her understanding and compassion. -5- TABLE OF CONTENTS Page 1. INTRODUCTION 18 2. BACKGROUND AND LITERATURE SURVEY 21 2.1 Metal Compounds in Petroleum 21 2.1-1 Properties of Porphyrins and Metalloporphyrins 24 2.1-1.a Porphyrins 24 2.1-1.b Metalloporphyrins 27 2.1-2 Geochemistry of Porphyrins 35 2.1-2.a Types of Porphyrins in Petroleum 35 2.1-2.b Origin of Porphyrin and Metallopor- 37 phyrin 2.1-3 Nonporphyrin Metal Compounds 40 2.2 Hydrodemetallation Reaction 45 2.2-1 Kinetics 46 2.2-1.a Thermal Demetallation and Nonhydro- 46 genative Demetallation 2.2-1.b Hydrodemetallation 48 2.2-2 Deposition of Metals on Hydrodesulphurization 58 Catalysts 2.2-2.a Concentration Distribution of Vanadium 58 and Nickel on Spent Catalysts 2.2-2.b Amount of Deposition 61 2.2-2.c Catalyst Aging 62 2.2-2.d Distribution along the Reactor Bed 64 2.3 Research and Development on Metal Removal Processes 66 3. MATERIALS AND EXPERIMENTAL PROCEDURES 69 3.1 Equipment for Hydrodemetallation Study 69 3.2 Materials 77 3.2-1 Catalyst 77 3.2-2 Solvent 85 3.2-3 Gas 85 3.2-4 Model Porphyrins and Metalloporphyrin; Com-- 87 pounds -6- Table of Contents (cont'd) Page 3.3 Experimental Procedures 90 3.3-1 Dissolving Model Compounds in Nujol 90 3.3-2 Pretreatment of Catalyst 94 3.3-3 Demetallation Experiment 94 3.3-4 Self Preparation Catalyst 98 3.4 Analysis 101 3.4-1 Liquid Sample 101 3.4-2 Solid Sample 107 3.4-3 Gas Sample 107 4. RESULTS 109 4.1 Nickel Porphyrin Runs for Commercially Available HDS 9A 109 or HDS 16A Catalyst 4.1-1 Air Prepared Ni-TPP Runs 109 4.1-l.a General Observations 109 4.1-1.b Kinetics 112 4.1-1.c Catalyst Effects 117 4.1-2 Helium Prepared Nickel Porphyrin Runs 124 4.1-2.a General Observations 124 4.1-2.b Kinetic Order 129 4.1-2.c Catalyst Effects 135 4.2 Vanadyl Porphyrin Runs 140 4.2-1 General Observations for VO-Etio Runs 140 4.2-2 Kinetic Order 144 4.2-3 Catalyst Effects 148 4.3 Free Base Porphyrin Runs 149 4.4 Mixed Nickel and Vanadyl Porphyrin Runs 152 4.4-1 General Observations 152 4.4-2 Kinetics 152 -7- Table of Contents (cont'd) Page 4.5 Self Preparation Catalyst Runs 162 4.5-1 General Observations 162 4.5-2 Effect of Cobalt or Molybdenum on Demetallation 166 Activity of Ni-Etio 5. DISCUSSION OF RESULTS 170 5.1 Diffusion Effects 170 5.1-1 Nickel Porphyrin Runs 170 5.1-2 Vanadyl Porphyrin Runs 174 5.1-3 Mixed Ni-Etio and VO-Etio Runs 175 5.2 Hydrogen Consumption 178 5.3 Intermediates and Products in Liquid Phase 180 5.3-1 Intermediates 180 5.3-2 Products 189 5.4 Intermediatea and Products on Catalyst 192 5-4-1 Intermediates 192 5.4-2 Products 192 5.5 Discussion on Kinetic Model and Possible Mechanism 19 5.5-1 Background 199 5.5-2 Results and Discussion 205 5.6 Catalyst Deactivation 218 5.7 Comparison among Nickel Runs 219 5.7-1 Between Air Prepared Ni-TPP and Helium Prepared 219 Nickel Porphyrin Runs 5.7-2 Comparison between Helium Prepared Ni-TPP and 220 Ni-Etio Runs 5.7-3 Comparison between CoO-MoO3 /A 203 and NiO-MoO /Al 2 0 223 Catalysts for Ni-Etio Runs 5.8 Comparison between Nickel and Vanadyl Porphyrin Runs 227 5.9 Comparison between Individual Ni-Etio, VO-Etio Runs 229 and Mixed Ni-Etio, VO-Etio Runs -8- Table of Contents (cont'd) Page 5.10 Comparison with Previous Work 231 5.11 Differentiating between Two First-Order Reactions and 235 a Single Second-Order Reaction 6. CONCLUSIONS AND SUGGESTIONS 247 6.1 Conclusions 247 6.2 Suggestions 250 7. BIBLIOGRAPHY 252' 8. NOMENCLATURE 266 APPENDIX Experimental Data 268 -9- LIST OF FIGURES Number Title Page 2-1 Nomenclature of Porphyrin System 25 2-2 The UV-Visible Absorption Spectrum (in CH Cl2 ) of Etio- 28 porphyrin-I and DPEP (Deoxophylloerythroe ioporphyrin). (Alturki et al. (1971)). 2-3 Visible Spectra of Porphyrins: (a) -Phylloporphyrin XV; 30 (b) Etioporphyrin I; (c) Rhodoporphyrin XV; (d) Deoxophy- lloerythroetioporphyrin. (Baker et al. (1978)). 2-4 Absorption Spectra for DPEP (Deoxophylloerythroetiopor- 33 phyrin) Type of Vanadyl Porphyrin (Top), and Nickel Porphyrin (Bottom). The curves that show Soret band peaks have been diluted from the others that show visible peaks. (Hodgson, et al. (1967)). 2-5 Absorption Spectra for Nickel Etioporphyrin I (Top) and 34 Vanadyl Etioporphyrin I (Bottom). Samples were Dissolved in Nujol First and Then Diluted by Xylene. Background: Xylene. 2-6 Scheme for The Transformation of Chlorophyll Qk to Stable 38 Vanadyl Porphyrins. 2-7 Examples for Nonporphyrin Metal Compounds: (1) Highly 41 Aromatic Porphyrin Chelates; (2) Porphyrin Decomposition Ligands, (Metals will Fill Up to the Center); and (3) Simple Complexes from Resin Molecules. (Yen (1975)-(a)). 2-8 Cross Sectional View of an Asphaltene Model. (Yen (1977)). 43 2-9 Defect Site in an Aromatic Sheet of the Asphaltene 43 Structure. (Yen (1974)). 2-10 Qualitative Changes in Asphaltenes and Surrounding 49 Resins During HDS Processing. (Beuther and Schmid (1963)). 2-11 Sulphur Removal Versus Nickel Removal and Vanadium 56 Removal for Several Vacuum Gas Oil. (Massagutov et al. (1967)). 2-12 Concentration Profile of Vanadium and Nickel on the 60 Desulphurization Catalyst after 50hrs Reaction. (Sato et al. (1971)) -10- List of Figures (cont'd) Number Title Page 2-13 Concentration Profile of Carbon, Vanadium, and Nickel 65 Along with the Reactor Bed. (Sato et al. (1970)). 3-1 Schematic of High Pressure Autoclave Reactor System for 70 Hydrodemetallation Study. 3-2 Autoclave Batch Reactor System. 71 3-3 List of Components for Figure 3-2. 72 3-4 Schematic of Main Body of 1-Liter Autoclave. 73 3-5 Schematic of Catalyst Loader and Porous Filter. 75 3-6 Pore Size Distribution for HDS-16A CoO-MoO 3/Al 2 03 80 Catalyst. 3-7 Pore Size Distribution for HDS-9A Ni0-Mo0 /Al 203 82 Catalyst. 3-8 Pore Size Distribution for VI-Alumina Catalyst Carrier. 84 3-9 Structure of Model Compounds: (1) TPP; (2) Etio-I; 88 (3) Ni-TPP; (4) Ni-Etio I; (5) VO-TPP; (6) VO-Etio I. 3-10 Structures of Chlorins (TPP type). 89 3-11 Apparatus for Removing Air from Nujol. 92 3-12 Apparatus for Dissolving Model Compounds in Nujol. 93 3-13 Absorption Spectra of Ni-TPP and VO-TPP.. Samples were 103 Dissolved in Nujol First and then Diluted by Xylene. Background: Xylene. 3-14 Absorption Spectra of Free Base Etio I and Free Base TPP.
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