Table Of Contentvii
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
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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.
