Control of the Distillate/Gasoline Ra Tio of Coal Derived and Other Liquids Jacqueline Anne Fahy
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CONTROL OF THE DISTILLATE/GASOLINE RA TIO OF COAL DERIVED AND OTHER LIQUIDS by JACQUELINE ANNE FAHY B.Sc. (Hons.) A Dissertation Submitted to the School of Chemical Engineering and Industrial Chemistry, University of New South Wales, in partial fulfilment of the requirements for the Degree of Doctor of Philosophy. University of New South Wales January 1992. CERTIFICATE OF ORIGINALITY I hereby declare that this submission is my own work and that, to the best of my knowledge and belief, it contains no material previously published or written by another person nor material which to a substantial extent has been accepted for the award of any other degree or diploma of a university or other institute of higher learning, except where due acknowledgement is made in the text. 1 ABSTRACT Environmental pressures are focusing attention on the removal of aromatics from hydrocarbon feedstocks. The present studies are concerned with the development of a complex catalyst for the hydroalkylation of benzene to cyclohexylbenzene and bicyclohexyl, a high cetane number diesel fuel blendstock. Studies have focused on nickel and rare earth exchanged 13X zeolite impregnated with platinum, listed in the patent literature as an efficient catalyst. Considerable problems were found with initial runs in that deactivation and coking occurred. Finally it proved possible to identify conditions such that cyclohexylbenzene was the major product with significant yields of cyclohexane and high molecular weight di- and tri-cyclohexylbenzene isomers also being produced. Hydrogenation of cyclohexylbenzene to bicyclohexyl was found to be efficient over a supponed nickel catalyst. The role of the catalyst components was then studied. The catalyst operates as a result of a fine balance of metal and acidic functions. Based on temperature programmed reduction and acidity measurements related to the activity of different catalysts, it was suggested that nickel is the major active hydrogenation catalyst. Platinum was active for hydrogenation but the main role of the precious metal appeared to be to allow reduction of nickel at low temperatures. The rare eanh salts were necessary to control catalyst acidity and assist in catalyst reduction at low 11 temperatures. The acidity of the zeolite support was responsible for cyclohexylbenzene selectivity. The effect of operation and pretreatment conditions on the performance of the various catalysts was used to provide support for these suggestions. It proved impossible to totally avoid catalyst deactivation, which precluded detailed study of the kinetics of the reaction. Hydrogenation of hydroalkylation products was shown to be possible, giving fully saturated bicyclohexyl as the only product. The cetane number performance of the combined hydroalkylation-hydrogenation product indicates its possible application as a distillate range fuel blendstock. Hydroalkylation of aromatics contained in coal and petroleum derived fuels was attempted, but was unsuccessful, apparently due to deactivation resulting from catalyst poisoning by sulphur. iii ACKNOWLEDGEMENTS I would like to express my appreciation to the many people who have helped me throughout the course of this project. In particular I would like to thank: My research supervisor, Professor David Trimm, for his encouragement, guidance and sense of humour, and Professor Mark Wainwright for his assistance with a number of experimental problems. The National Energy Research Development and Demonstration Council and BHP for funding the project, and the staff at BHP Melbourne Research Laboratories, especially Noam White and David Cookson for their generosity and enthusiasm. The technical staff, especially Phillip McAuley, for their efforts in the construction and maintenance of my experimental equipment, and their friendship throughout, and the staff of the School of Chemical Engineering, especially Wendy Wartho, for their time and patience. To my fellow postgraduate students, Daniel Thomas, Jennifer Jones and Brett Moss, for their support and friendship. And especially to my mother and John Somerville for their special efforts, patience and understanding. iv. TABLE OF CONTENTS ABSTRACT ACKNOWLEDGEMENTS 111. TABLE OF CONTENTS iv. TABLES viii. LIST OF FIGURES X. CHAPTER 1. INTRODUCTION 1. 1.1. CRUDE OIL SUPPLY AND DEMAND 1. 1.1.1. Synthetic Fuels 4. 1.1.2. Coal Liquefaction 8. 1.1.3. Characteristics of Coal Derived Liquids 14. 1.2. THE IMPACT OF ENVIRONMENTAL LEGISLATION ON REFINING 17. 1.2.1. Environmental Impact 18. 2. TRANSPORT FUELS 22. 2.1. PETROLEUM BASED TRANSPORT FUELS 22. 2.1.1. Fuel Specifications 23. 2.1.1.1. Gasoline 23. 2.1.1.2. Australian Diesel Fuel 25. 2.1.1.3. Jet Fuel 31. 2.2. COAL DERIVED LIQUIDS AS TRANSPORT FUELS 35. 2.2.1. Suitability of Coal Derived Liquids 35. 2.2.2. Hyd.roprocessing of Coal Derived Liquids 38. 2.3. BACKGROUND TO PRESENT STUDY 43. v. CHAPTER 3. CATALYST DESIGN 53. 3.1. HYDROGENATION OF BENZENE 53. 3.2. HYDROGENATION OF SUBSTITUTED BENZENES 61. 3.3. ALKYLATION 66. 3.3.1. Alkylation of Aromatics 68. 3.4. ZEOLITES 70. 3.4.1. Acidity of Zeolites 75. 3.4.2. Application of Zeolites in Acid Catalysis 79. 3.5. HYDROALKYLATION 81. 4. PROJECT OBJECTIVES 88. 5. EXPERIMENTAL TECHNIQUES 90. 5.1. INTRODUCTION 90. 5.2. MATERIALS 92. 5.2.1. Gases 92. 5.2.2. Chemicals 93. 5.3. CATALYSTS 95. 5.3.1. Cation Exchange of 2.eolites 96. 5.3.2. Impregnation of Catalysts 98. 5.3.3. Calcination 99. 5.3.4. Catalyst Characterisation 99. 5.3.4.1. Bulle Density 100. 5.3.4.2. Total Surface Area 100. 5.3.4.3. Metal Surface Area 101. 5.3.4.4. Elemental Analysis 103. 5.3.4.5. Temperature Programmed Reduction and Oxidation 105. 5.3.4.6. Acidity Measurement 106. 5.3.4.7. Microscopic Analysis 108. vi. CHAYfER 5. 5.4. HYDROALKYLATION EXPERIMENTS 110. 5.4.1. Apparatus 110. 5.4.2. Procedure 113. 5.5. CHROMATOGRAPlilC ANALYSIS 115. 6. HYDROALKYLATION OF MODEL COMPOUNDS - RESULTS AND DISCUSSION 122. 6.1. HYDROALKYLATION OF BENZENE - RESULTS 123. 6.1.1. Introduction 123. 6.1.2. Initial Testing 124. 6.1.3. Role of Metals 134. 6.1.4. Catalyst Pretreatment 143. 6.1.5. Temperature Programmed Reduction 151. 6.1.6. Effect of Catalyst Support 159. 6.1.7. Catalyst Treatments 164. 6.1.7.1. Steaming as an Alternative to Calcination 164. 6.1.7.2. Chloride Treatment 166. 6.1.7.3. Scxlium Carbonate Treatment 169. 6.1..7.4. Regeneration and Cycles of Use 171. 6.2. HYDROALKYLATION OF BENZENE - DISCUSSION 173. 6.2.1. Initial Testing 173. 6.2.2. Role of Metals 175. 6.2.3. Support Effects 213. 6.2.4. Catalyst Treatments 223. 6.2.4.1. Steaming 223. 6.2.4.2. Chloride Treatment 224. 6.2.4.3. Sodium Carbonate Treatment 225. 6.2.4.4. Regeneration and Cycles of Use 225. vii. CHAPTER 6.3. HYDROALKYLATION OF OTHER MODEL COMPOUNDS 227. 6.3.1. Hydroalkylation of Beni.ene/foluene Mixture 227. 6.3.2. Synthetic Coal Derived Liquid 228. 7. HYDROALKYLATION OF COAL DERIVED AND OTHER LIQUIDS - RESULTS AND DISCUSSION 230. 7.1. HYDROALKYLATION OF COAL DERIVED LIQUIDS 230. 7 .1.1. Feed Characteristics 230. 7 .1.2. Hydroalkylation Trials 231. 7.2. DISCUSSION OF HYDROALKYLA TION OF COAL DERIVED LIQUIDS 233. 7.3. HYDROALKYLATION OF DIESEL FRACTION 235. 7 .3.1. Feed Characteristics 235. 7.3.2. Hydroalkylation Trial 236. 7.4. DISCUSSION OF HYDROALKYLA TION OF DIESEL FRACTION 238. 8. RESULTS AND DISCUSSION - HYDROGENATION AND COMBINED HYDROALKYLATION/HYDROGENATION 240. 8.1. HYDROGENATION OF BIPHENYL 241. 8.2. DUAL CATALYST BED - Combined Hydroalkylation/Hydrogenation 242. 8.3. HYDROGENATION OF CYCLOHEXYLBENZENE 243. 8.4. HYDROGENATION TRIALS AT BHPR-ML 244. 9. CONCLUSIONS AND RECOMMENDATIONS 247. 9.1. CONCLUSIONS 247. 9.2. RECOMMENDATIONS 252. REFERENCES 254. Vlll. TABLES Table 1.1 Demonstrated Economic Resources and Utilisation Rates of Primary Fuels. 5. Table 1.2 Analytical Data for Gasolines Derived from Wandoan and Yallourn Coal Liquefaction Syncrudes Compared to Petroleum based Gasoline. 16. Table 1.3 Summer _Baseline Gasoline vs. the Clean Air Act Mandate. 19. Table 2.1 Fuel Boiling Ranges and Primary Requirements. 22. Table 2.2 An Australian Specification for Unleaded Gasoline. 24. Table 2.3 ASTM and Draft Australian Specifications for Diesel Fuels. 26. Table 2.4 Specification for Jet A-1 Aviation Turbine Fuel. 32. Table 2.5 Possible Jet Fuel and Diesel Fuel Blending. Compounds Derivable from Aromatics. 44. Table 2.6 Major Components in Refonnate of Naphtha. 49. Table 2.7 Synthetic Mixtures to Approximate Jet and Diesel Fuels. 49. Table 2.8 Test Results on Synthetic Mixtures. 50. Table 2.9 Test Results on Synthetic Mixtures. 50. Table 3.1 Structural Parameters of Zeolite Catalysts. 73. Table 3.2 Catalytically Important Properties of Zeolites. 74. Table 5.1 Gas Specifications. 92. Table 5.2 Chemical Specifications. 93. Table 5.3 Catalyst Specifications. 95. Table 5.4 Gas Chromatography Retention Times and Relative Area Response Factors. 121. ix. Table 6.1 Hydroalkylation Trials Using Catalyst A (Pt/Ni/RFJzeolite-13X). 127. Table 6.2 Composition of Hydroalkylation Catalysts. 135. Table 6.3 The Effect of Catalyst Metal Content on Benzene Hydroalkylation. 137. Table 6.4 Characteristics of Hydroalkylation Catalysts of Differing Suppons. 160. Table 6.5 Benzene Hydroalkylation with Catalysts of Varying Supports. 161. Table 6.6 Acidity Determinations on Catalysts of Varying Rare Earth Metal Contents (Catalysts I,J,K,A). 218. Table 6.7 Composi~on of Coal Derived Liquid Synthetic Mixture. 228. Table 7.1 Hydroalkylation of Coal Derived Liquids using Catalyst A. 232. Table 7.2 Diesel Hydroalkylation Trial using Catalyst A. 237. Table 8.1 Composition of Products BHPR-ML Hydrogenation Trials. 245. X. LIST OF FIGURES Page Figure 1.1 Australian Petroleum Production versus Demand 1988-1998, API Projections. 2. Figure 1.2 Petroleum Products Demand 1989/1999.