Fluid Catalytic Cracking V Materials and Technological Innovations PDF
Preview Fluid Catalytic Cracking V Materials and Technological Innovations
vii List of Contributors .S A1-Khattaf H. de Lasa Chemical Reactor Engineering Centre Chemical Reactor Engineering Centre Faculty of Engineering Faculty of Engineering University of Western Ontario University of Western Ontario London, Ontario London, Ontario CANADA N6A 5B9 CANADA N6A 5B9 S.-I. Andersson M.A. den Hollander Chalmers University of Technology Industrial Catalysis Department of Applied Surface Chemistry Department of Chemical Technology SE-41296 Gothenburg Faculty of Applied Sciences SWEDEN Delft University of Technology Julianalaan 631 A. Auroux 2628 BL Delft Institut de Recherches sur la Catalyse THE NETHERLANDS CNRS 2 Av. A. Einstein H. Eckert 69626 Villeurbanne Institut ftir Physikalische Chemie FRANCE ehcsili~ftseW Wilhelms-Universit~it Miinster Schlossplatz 7 R.A. Beyerlein D-48149 Miinster National Institute of Standards and Technology GERMANY Gaithersburg, MD 20899-4730 USA I. Eilos Fortum Oyj L.T. Boock P.O. Box 310 Grace Davision 06101 Porvoo 7500 Grace Drive FINLAND Columbia, MD 21044 USA A.E. Fallick Scottish Universities Research & Reactor M. Castro Diaz Centre University of Strathclyde East Kilbride Department of Pure and Applied Chemistry Glasgow G75 0QU Glasgow 1G 1XL UK Scotland UK J. Frasch Laboratoire de Matrriaux Minrraux (CNRS- A. Corma ENSCMu) Instituto de Tecnologfa Qufmica 3 rue Alfred Wemer UPV-CSIC F-68093 Mulhouse Avda. de los Naranjos, s/n FRANCE 46022 Valencia SPAIN viii .R Garcia-de-Le6n P.J. Hall Programa de Investigaci6n en Tratiamento de University of Strathclyde Crudo Maya Department of Pure and Applied Chemistry Instituto Mexicano del oe16rteP Glasgow 1G LX1 Ejo Central L~aro C&denas 251 Scotland C.P. 07730 UK M6xico, D.F. MEXICO .M He Research Institute of Petroleum Processing W.R. Gilbert China Petrochemical Corporation PETROBAS R & D Center Beijing 380001 Process Division P.R. CHINA Rio de Janeiro, 21949-900 BRAZIL .F Hern~dez-Belmin Programa de Investigaci6n en Tratiamento .R Gonz~ilez-Serrano de CrudoM aya Programa de Investigaci6n en Tratiamento de Instituto Mexicano del oe16rteP Crudo Maya Ejo Central L~aro C~denas 251 Instituto Mexicano del oe16rteP C.P. 07730 Ejo Central L~aro C&denas 251 M6xico, D.F. C.P. 07730 MEXICO M6xico, D.F. MEXICO J. Hiltunen Fortum jyO M.-Y. Gu P.O. Box 310 Research Institute of Petroleum Processing 06101 Porvoo (RIPP) FINLAND SINOPEC Beijing .R Hughes CHINA University of Salford Chemical Engineering Unit N.J. Gudde Salford M5 4WT ,PB Oil Technology Centre UK Chertsey Road Sunbury-on-Thames .A Humphries Middlesex TW16 7LN Akzo Nobel Catalysts Inc. UK 2625 Bay Area Blvd., Suite 250 Houston, TX 77058 .P Gullbrand USA Instituto de Tecnologfa Qufmica UPV-CSIC .P Imhof Avda. de los Naranjos, sin Akzo Nobel Catalysts 46022 Valencia Research Center Catalysts SPAIN Amsterdam THE NETHERLANDS .P Hagelberg Fortum Oyj .K nenii/leksi/i/J P.O. Box 310 Fortum Oyj 06101 Porvoo P.O. Box 20 FINLAND 00048 Fortum FINLAND R. Jonker .B Lebeau Akzo Nobel Catalysts Laboratoire de Mat6riaux Min6raux Research Center Catalysts (CNRS-ENSCMu) Amsterdam 3 rue Alfred Werner THE NETHERLANDS F-68093 Mulhouse FRANCE M. Kalwei Institut fiir Physikalische Chemie M.I. Levinbuk Wilhelms-Universit~it Westf~ilische Miinster Gubkin Moscow Oil and Gas University Schlossplatz 7 65 Leninsky prosp. D-48149 Miinster Moscow 117917 GERMANY THE RUSSIAN FEDERATION .S Katoh C.-Y. Li Kashima Oil Company Research Institute of Petroleum Processing Kashima (RIPP) JAPAN SINOPEC Beijing G.W. Ketley CHINA BP, Oil Technology Centre Chertsey Road .K Lipiainen Sunbury-on-Thames Fortum Oyj Middlesex TW16 7LN P.O. Box 310 UK 06101 Porvoo FINLAND P. Knuuttila Fortum Oyj F. L6pez-Isunza P.O. Box 310 Departamentod e Ingenierfa de Procesos e 06101 Porvoo Hidrfiulica FINLAND Universidad Aut6noma Metropolitana- Iztapalapa C.L. (Arthur) Koon Av. Michoacfin y La Purisima sin University of Salford Col. Vicentina Chemical Engineering Unit Iztapalapa Salford M5 4WT M6xico 09340, D.F. UK MEXICO C.W. Kuehler E. L6pez-Salinas Akzo Nobel Catalysts Programa de Investigaci6n en Tratiamento de Houston, Texas Crudo Maya USA Instituto Mexicano del Petr61eo Ejo Central Cfirdenas Lfizaro 152 A.A. Lappas C.P. 07730 Chemical Process Engineering Research M6xico, D.F. Institut (CPERI) MEXICO Department of Chemical Engineering University of Thessaloniki Y. Lu P.O. Box 163 Research Institute of PetroleuPmr ocessing 57001 Thermi, Thessaloniki China Petrochemical Corporation GREECE Beijing 100083 P.R. CHINA J. Majander J.C. Moreno-Mayorga Fortum Oyj Programa de Investigaci6n en Tratiamento de P.O. Box 20 Crudo Maya 00048 Fortum Instituto Mexicano del Petr61eo FINLAND Ejo Central L~aro sanedri~C 251 C.P. 07730 M. Makkee M6xico, D.F. Industrial Catalysis MEXICO Department of Chemical Technology Faculty of Applied Sciences J.A. Moulijn Delft University of Technology Industrial Catalysis Julianalaan 631 Department of Chemical Technology 2628 BL Delft Faculty of Applied Sciences THE NETHERLANDS Delft University of Technology Julianalaan 631 S.C. Martin 2628 BL Delft University of Strathclyde THE NETHERLANDS Department of Pure and Applied Chemistry Glasgow 1G LX1 .T Myrstad Scotland Statoil's Research Centre UK N-7005 Trondheim NORWAY C. Martfnez Instituto de Tecnologfa Quimica M. Nakamura UPV-CSIC Nippon Ketjen Avda. de los Naranjos, s/n Tokyo 46022 Valencia JAPAN SPAIN V.M. Niemi G.B. McVicker Fortum Oyj ExxonMobil Research & Engineering Co. P.O. Box 310 Annandale, NJ 08801 06101 Porvoo USA FINLAND V.B. Melnikov .S Numan Gubkin Moscow Oil and Gas University Gubkin Moscow Oil and Gas University 65 Leninsky prosp. 65 Leninsky prosp. Moscow 117917 Moscow 117917 THE RUSSIAN FEDERATION THE RUSSIAN FEDERATION E. Mogica-Martfnez M.L. Occelli Programa de Investigaci6n en Tratiamento de MLO Consulting Crudo Maya Atlanta, GA 30328 Instituto Mexicano del Petr61eo USA Ejo Central L~aro C~denas 251 C.P. 07730 .P O'Connor M6xico, D.F. Akzo Nobel Catalysts MEXICO Amersfoort THE NETHERLANDS J. Patarin X. Shu Laboratoire de Mat6riaux Min6raux Research Institute of Petroleum Processing (CNRS-ENSCMu) China Petrochemical Corporation 3 rue Alfred Wemer Beijing 100083 F-68093 Mulhouse P.R. CHINA FRANCE B. Skocpol V.A. Patrikeev Akzo Nobel Catalysts Salavat Catalyst Factory Amersfoort Salavat 453206 THE NETHERLANDS THE RUSSIAN FEDERATION C.E. Snape M.L. Pavlov University of Strathclyde Ishimbai Catalyst Factory Department of Pure and Applied Chemistry Ishimbai 453210 Glasgow 1G LX1 THE RUSSIAN FEDERATION Scotland UK .A Petre Institut de Recherches sur la Catalyse .J Song CNRS Research Institute of Petroleum Processing 2 Av. A. Einstein China Petrochemical Corporation 69626 Villeurbanne Beijing 100083 FRANCE P.R. CHINA T.F. Petti M. Soulard Grace Davision Laboratoire de Mat6riaux Min6raux 7500 Grace Drive (CNRS-ENSCMu) Columbia, MD 21044 3 rue Alfred Werner USA F-68093 Mulhouse FRANCE Z.-H. Qiu Research Institute of Petroleum Processing L.-W. Tang (RIPP) Research Institute of Petroleum Processing SINOPEC (RIPP) Beijing SINOPEC CHINA Beijing CHINA .J neni~pp6R Fortum Oyj Z.A. Tsagrasouli P.O. Box 20 Chemical Process Engineering Research 00048 Fortum Institut (CPERI) FINLAND Department of ChemicaEln gineering University of Thessaloniki W.L. Schuette (deceased) P.O. Box 163 57001 Thermi, Thessaloniki A.E. Schweizer GREECE ExxonMobil Refining and Supply Company Process Research Laboratories Y.R. Tyagi P.O. Box 2226 University of Strathclyde Baton Rouge, LA 70821-2226 Department of Pure and Applied Chemistry USA Glasgow 1G 1XL, Scotland iix I.A. Vasalos Chemical Process Engineering Research Institute (CPERI) Department of Chemical Engineering University of Thessaloniki P.O. Box 163 57001 Thermi, Thessaloniki GREECE C.L. Wallace University of Strathclyde Department of Pure and Applied Chemistry Glasgow 1G LX1 Scotland UK A. Wrlker Institut fiir Physikalische Chemie Westf/ilische Wilhelms-Universi~t Miinster Schlossplatz 7 D-48149 Miinster GERMANY S.-H. Yan Research Institute of Petroleum Processing (RIPP) SINOPEC Beijing CHINA S.J. Yanik Akzo Nobel Catalysts Singapore Preface Catalyst production for the transformation of crudes into gasoline and other fuel products is a $2.1 billion/year business and fluid cracking catalysts (FCCs) represent almost half of the refinery catalyst market .M( MacCoy, Chemical and Engineering News, p. ,71 September 20 (1999)). During the cracking reactions, the FCC surface is contaminated by metals (Ni, V, Fe, Cu, Na) and by coke deposition. As a result, the catalyst activity and product selectivity is reduced to unacceptable levels thus forcing refiners to replace part of the recirculating equilibrium FCC inventory with fresh FCC to compensate for losses in catalyst performance. About 1,100 tons/day of FCC are used worldwide in over 200 fluid cracking catalyst units (FCCUs). Today, the worldwide capacity to produce gasoline exceeds the 460 million gal/day. In addition, FCCs are used in the commercial synthesis of acrylonitrile, phthalic anhydride and maleic anhydridie and in the production of 45% of the world propylene (Chemical and Engineering News, p. ,15 November ,32 1998). In recognition of the great technological importance of the FCC process, on November ,3 1998 the first commercial fluid bed reactor using catalytic cracking constructed at the Exxon Baton Rouge refinery, was designated a National Historic Chemical Landmark by the American Chemical Society. It is for these reasons that refiners' interest in FCC research has remained high through the years and almost independent of crude oil prices. However, recent oil company mergers and the dissolution of research laboratory, has drastically decreased the number of researchers involved in petroleum refining research projects. As a results the emphasis has shifted from new materials research to process improvements and this trend is clearly reflected in the type of papers contained in this volume. Modem spectroscopic techniques continue to be essential to the understanding of catalysts performance and several chapters in the book describe the use of ,1A72 29Si and C3~ NMR to study variation in FCC acidity during aging and coke deposition. In addition several chapters have been dedicated to the modeling of FCC deactivation, and to the understanding of contact times on FCC performance. Refiners efforts to conform with environmental regulations are reflected in chapters dealing with sulfur removal, metals contaminants and olefins generation In conclusion, as before we would like to express our gratitude to our colleagues for acting as technical referees. The views and conclusion expressed herein are those of the chapter authors whom we sincerely thanks for their time and effort in presenting their research at the Symposium and in preparing the camera ready manuscripts for this Volume. Mario L. Occelli and Paul O'Connor November 2000 seidutS ni ecafruS ecneicS dna sisylataC 431 .L.M illeccO dna .P rennoC'O )srotidE( (cid:14)9 1002 reiveslE ecneicS .V.B llA sthgir devreser Defect Structure and Acid Catalysis of High Silica, FAU-Framework Zeolites: Effects of Aluminum Removal and of Basic Metal Oxide Addition Robert A. Beyerlein* and Gary B. McVicker* *National Institute of Standards and Technology, Gaithersburg, MD 20899-4730 *ExxonMobil Research & Engineering Co., Annandale, NJ 08801 The catalytic properties of ultrastable Y (USY) are directly influenced by the zeolite destruction that occurs during formation of USY and during subsequent hydrothermal treatment. Mildly steamed USY materials exhibit a secondary pore system (mesopores) of 5- 50 nm dimensions, which are evident as light amorphous zones in Transmission Electron Microscopy (TEM). Combined high resolution electron microscopy (HREM) and analytical electron microscopy (AEM) investigations on hydrothermally deaiuminated USY materials have shown that, in regions of high defect concentration, mesopores "coalesce" to form channels and cracks, which, upon extended hydrothermal treatment, define the boundaries of fractured crystallite fragments. The predominant fate of aluminum ejected from lattice sites appears to be closely associated with dark bands, which decorate the newly formed fracture boundaries. A smaller proportion of ejected aluminum exists as "nonframework AI" within the zeolite cages. High silica Y materials, having little or no nonframework 1A exhibit poor catalytic activity for a large variety of acidity-dependent reactions. Investigations on mildly dealuminated zeolites suggest that the origin of the enhanced catalytic activity is a synergistic interaction between Br0nsted (framework) and highly dispersed Lewis (nonframework) acid sites. The enhanced cracking, isomerization activity associated with the presence of highly dispersed nonframework 1A species i) is not reflected in direct measures of solid acidity obtained, for example, by calorimetry or by NMR spectroscopy, and ii) is not consistent with a major increase in average acid site strength. Numerous structure/function studies indicate that the critical nonframework 1A species may exist sa cationic species in the small cages of dealuminated H-Y. By contrast, partial exchange of high silica Y materials with monovalent cations, such as Na or K, leads to significant reduction in activity, presumably by poisoning acid sites. In prior studies of isobutane conversion over dealuminated H-Y, it was shown that the addition of sodium equivalent to 3/1 of the total framework 1A atoms completely eliminates catalyst activity. Extensions of these poisoning studies show that addition of potassium produces a much stronger poisoning effect, with one K + ion giving an activity suppression roughly equivalent to that produced by two Na § ions. Calcium addition gives rise to a poisoning effect intermediate between those of Na + and K + at low levels of exchange, ca. 10%, but is more mild than that of sodium sa Ca ++ exchange levels exceed 20%. Previous correlations of isobutane conversion activity with framework composition support a direct dependence of carbocation-facilitated processes on framework aluminum ,)F1A( with a linear dependence of carbonium ion rates on F1A content. The observed linear dependencies exhibited for Na or K addition show that the primary effect of poisoning, or of F1A removal, is a decrease in the number of active sites. Measured selectivities for carbocation products indicate a limiting site density of about A1F/ucell - 8 (out of a maximum 56 1A among 192 tetrahedral framework sites for a starting zeolite Y), below which carbocation activity diminishes rapidly. Consistent with previous discussion of dual mechanisms, the results for formation of methane, a stable reaction product marker, show that the initiation step and the secondary carbocation processes are intimately linked over the entire range of acid site content, whether manipulated by dealumination or by permanent poisoning by basic alkali or alkaline metal oxides. .1 INTRODUCTION The importance of acid catalysis for the production of fuel and petrochemicals is underscored by recent environmental mandates calling for reformulated motor fuel that contains greater proportions of high octane, branched paraffins and oxygenates. Environmental concerns about the catalysts themselves, particularly the highly corrosive and toxic liquid acids, such as sulfuric and hydrofluoric acids, have created a need for stable, strongly acidic solid acids. Combined theoretical and experimental studies of the last decade have substantially improved our level of understanding of solid acidity in zeolites. The prospect for obtaining a detailed molecular level understanding of heterogeneous catalysts that could better guide the search for improved catalysts appears to be optimum for crystalline solid acids. It is the object of this paper to review our current understanding of the predominant solid acid catalyst, the family of protonated FAU-framework materials stabilized by hydrothermal treatment, originally designated ultrastable Y (USY) ,1 2 and commonly referred to as dealuminated H-Y (H-ultrastable Y). The catalytic properties of ultrastable Y are directly influenced by the zeolite destruction attending its formation and further modification by subsequent hydrothermal treatment. For ultrastable, high silica, FAU framework materials prepared by steam dealumination, interpretation of catalytic data is complicated by the presence of entrained, nonframework aluminum (NFA) species. Although the individual and collective roles of framework and nonframework aluminum species are not well understood, it is clear that the presence of some nonframework ,1A presumably highly dispersed, is essential for the strong solid acidity exhibited by high silica H-Y 3-5. While the critical nonframework species are not easily subject to direct observation, the existence of isolated, intracrystalline NFA species in dealuminated H-Y materials is not in doubt. The importance of certain nonframework 1A species for the ability of zeolitic solid acids to catalyze acidity-demanding reactions 6, such sa alkane skeletal isomerization or cracking, is not limited to H-Y. An abundant literature shows a consensus that the development of "enhanced carbocation activity" in mildly steamed HZSM-5 is also critically dependent on the presence of nonframework 1A 6-9. Enhancement of carbocation activity, generally associated with BrCnsted acidity, has also been observed in mildly steamed mordenite 10 and in HZSM-20 11 . Knowledge of framework geometry is essential for understanding overall reactivity patterns for hydrocarbon conversions over these open framework solid acids. The well-known features of "molecular traffic management" exhibited by these materials are not always limited to molecular sieving, that is reactant or product size exclusion effects. For example, at reaction temperatures of 400 ~ to 500~ dealuminated H-USY and dealuminated mordenite (large pore zeolites)each catalyze the isomerization of isobutane to n-butane 12, 13. Under similar conditions, the medium pore system HZSM-5 produces relatively little n-butane, but instead yields much methane and propylene 13, 14. The dramatically different product selectivities in the latter case are attributed to the more severe spatial restrictions of the medium pore ZSM-5, which tend to inhibit hydride transfer and oligomerization/back- cracking processes involving bulky reaction intermediates. Ever since the rapid commercialization in the early 1960's of a zeolite-catalyzed process for gas oil cracking 15, 16, zeolites have comprised the predominant usage of solid acid catalysts. The characterization and application of high silica, protonated zeolites in fluid catalytic cracking has been reviewed by Scherzer 17. A broader overview of the use of zeolites in hydrocarbon processing is found in Maxwell and Stork 18. A large number of potential zeolite catalyst applications in the synthesis of intermediates and fine chemicals have been discussed by Hoelderich et al. 19-21. An outstanding attribute of the acidic FAU H-Y materials is their ability to catalyze intermolecular hydride transfer reactions in numerous hydrocarbon conversions, which are all but missing in less strongly acidic amorphous solid acids. Despite high industrial and academic interest, the nature of the active site in solid acids remains largely unresolved. In systems of wide interest such as a protonated zeolite, a chlorided or fluorided alumina, or sulfated zirconia, we are unable to quantify the distribution or relative importance of BrCnsted and/or Lewis sites, the surface acid strength, or the concentration of acid sites 22. Recent advances in physical characterization of sites have substantially improved our understanding of these issues. Both H1 MASNMR 8, 23-25 and C31 MASNMR 26 have been effective in formalizing the structure/function relationships for BrCnsted acid sites in HZSM-5, an especially favorable system for analysis owing to its low BrCnsted acid site density and high crystallinity. So far, only "clean framework" ZSM-5 has been reasonably well characterized. The extension of these and related spectroscopic studies to the more complex systems represented by mildly steamed, carbocation activity enhanced HZSM-5 or dealuminated H-Y comprises a significant experimental and data interpretation challenge.
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