Note: Descriptions are shown in the official language in which they were submitted.
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MOLECULAR SIEVE COMPOSITIONS, CATALYST THEREOF,
THEIR MAKING AND USE IN CONVERSION PROCESSES
[0001] The present invention relates to molecular sieve compositions and
catalysts containing the same, to the synthesis of such compositions and
catalysts
and to the use of such compositions and catalysts in conversion processes to
produce olefin(s).
[0002] Olefins are traditionally produced from petroleum feedstocks by
catalytic or steam cracking processes. These cracking processes, especially
steam
cracking, produce light olefin(s), such as ethylene and/or propylene, from a
variety
of hydrocarbon feedstocks. Ethylene and propylene are important commodity
petrochemicals useful in a variety of processes for making plastics and other
chemical compounds.
[0003] The petrochemical industry has known for some time that
oxygenates, especially alcohols, are convertible into light olefin(s). The
preferred
alcohol for light olefin production is methanol and the preferred process for
converting a methanol-containing feedstock into light olefin(s), primarily
ethylene
and/or propylene, involves contacting the feedstock with a molecular sieve
catalyst composition.
[0004] There are many different types of molecular sieve known to convert
oxygenate containing feedstocks into one or more olefin(s). For example, U.S.
Patent No. 5,367,100 describes the use of the zeolite, ZSM-5, to convert
methanol
into olefin(s); U.S. Patent No. 4,062,905 discusses the conversion of methanol
and
other oxygenates to ethylene and propylene using crystalline aluminosilicate
zeolites, for example Zeolite T, ZK5, erionite and chabazite; U.S. Patent No.
4,079,095 describes the use of ZSM-34 to convert methanol to hydrocarbon
products such as ethylene and propylene; and U.S. Patent No. 4,310,440
describes
producing light olefin(s) from an alcohol using a crystalline
aluminophosphate,
often designated A1PO4.
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[0005] Some of the most useful molecular sieves for converting methanol to
olefin(s) are silicoaluminophosphate (SAPO) molecular sieves.
Silicoaluminophosphate molecular sieves contain a three-dimensional
microporous crystalline framework structure of [Si04], [A104] and [P04] corner
sharing tetrahedral units. Synthesis of a SAPO molecular sieve, its
formulation
into a catalyst, and its use in converting a feedstock into olefin(s),
particularly
where the feedstock is methanol, are disclosed in U.S. Patent Nos. 4,499,327,
4,677,242, 4,677,243, 4,873,390, 5,095,163, 5,714,662 and 6,166,282.
[0006] When used in the conversion of methanol to olefins, most molecular
sieves, including SAPO molecular sieves, undergo rapid coking and hence
require
frequent regeneration, typically involving exposure of the catalyst to high
temperatures and steaming environments. As a result, current methanol
conversion catalysts tend to have a limited useful lifetime and hence there is
a
need to provide a molecular sieve catalyst composition which exhibits an
enhanced lifetime particularly when used in the conversion of methanol to
olefins.
[0007] U.S. Patent No. 4,465,889 describes a catalyst composition
comprising a silicalite molecular sieve impregnated with a thorium, zirconium,
or
titanium metal oxide for use in converting methanol, dimethyl ether, or a
mixture
thereof into a hydrocarbon product rich in iso-C4 compounds.
[0008] U.S. Patent No. 6,180,828 discusses the use of a modified molecular
sieve to produce methylamines from methanol and ammonia where, for example,
a silicoaluminophosphate molecular sieve is combined with one or more
modifiers, such as a zirconium oxide, a titanium oxide, an yttrium oxide,
montmorillonite or kaolinite.
[0009] U.S. Patent No. 5,417,949 relates to a process for converting noxious
nitrogen oxides in an oxygen containing effluent into nitrogen and water using
a
molecular sieve and a metal oxide binder, where the preferred binder is
titania and
the molecular sieve is an aluminosilicate.
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[0010] EP-A-312981 discloses a process for cracking vanadium-containing
hydrocarbon feed streams using a catalyst composition comprising a physical
mixture of a zeolite embedded in an inorganic refractory matrix material and
at
least one oxide of beryllium, magnesium, calcium, strontium, barium or
lanthanum, preferably magnesium oxide, on a silica-containing support
material.
[0011] Fang and Inui, Effects of decrease in number of acid sites located on
the external surface of Ni-SAPO-34 crystalline catalyst by the mechanochemical
method, Catalysis Letters 53, pages 171-176 (1998) disclose that the shape
selectivity can be enhanced and the coke formation mitigated in the conversion
of
methanol to ethylene over Ni-SAPO-34 by milling the catalyst with MgO, CaO,
BaO or Cs20 on microspherical non-porous silica, with BaO being most
preferred.
[0012] International Publication No. WO 98/29370 discloses the conversion
of oxygenates to olefins over a small pore non-zeolitic molecular sieve
containing
a metal selected from the group consisting of a lanthanide, an actinide,
scandium,
yttrium, a Group 4 metal, a Group 5 metal or combinations thereof.
[0013] In one aspect, the invention resides in a catalyst composition
comprising a molecular sieve and at least one oxide of a metal selected from
Group 3 of the Periodic Table of Elements, the Lanthanide series of elements
and
the Actinide series of elements, wherein said metal oxide has an uptake of
carbon
dioxide at 100 C of at least 0.03, and typically at least 0.04 mg/m2 of the
metal
oxide.
[0014] Preferably, the catalyst composition also includes at least one of a
binder and a matrix material different from said metal oxide.
[0015] In one embodiment, said metal oxide is selected from lanthanum
oxide, yttrium oxide, scandium oxide, cerium oxide, praseodymium oxide,
neodymium oxide, samarium oxide, thorium oxide and mixtures thereof.
[0016] Preferably, the molecular sieve conveniently comprises a
silicoaluminophosphate.
[0017] In another aspect, the invention resides in a molecular sieve catalyst
composition comprising a Group 3 metal oxide and/or an oxide of the Lanthanide
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or Actinide series elements, a binder, a matrix material, and a
silicoaluminophosphate molecular sieve.
[0018] In yet another aspect, the invention resides in a method for making a
catalyst composition, the method comprising physically mixing first particles
comprising a molecular sieve with second particles comprising at least one
oxide
of a metal selected from Group 3 of the Periodic Table of Elements, the
Lanthanide series of elements and the Actinide series of elements, wherein
said
metal oxide has an uptake of carbon dioxide at 100 C of at least 0.03 mg/m2 of
the
metal oxide particles.
[0019] Preferably, said second particles are produced by causing a hydrated
precursor of the metal oxide to precipitate from a solution containing ions of
the
metal, hydrothermally treating the hydrated precursor at a temperature of at
least
80 C for up to 10 days and then calcining the hydrated precursor at a
temperature
in the range of from 400 C to 900 C.
[0020] In a further aspect, the invention is directed to a process for
producing olefin(s) by converting a feedstock, such as an oxygenate,
conveniently
an alcohol, for example methanol, into one or more olefin(s) in the presence
of a
catalyst composition a molecular sieve and at least one oxide of a metal
selected
from Group 3 of the Periodic Table of Elements, the Lanthanide series of
elements
and the Actinide series of elements, wherein said metal oxide has an uptake of
carbon dioxide at 100 C of at least 0.03 mg/m2 of the metal oxide.
[0021] In one embodiment, the catalyst composition has a Lifetime
Enhancement Index (LEI) greater than 1, such as greater than 1.5. LEI is
defined
herein as the ratio of the lifetime of the catalyst composition to that of the
same
catalyst composition in the absence of an active metal oxide.
[0022] The invention is directed to a molecular sieve catalyst composition
and to its use in the conversion of hydrocarbon feedstocks, particularly
oxygenated feedstocks, into olefin(s). It has been found that combining a
molecular sieve with an active metal oxide from Group 3 of the Periodic Table
of
Elements (using the IUPAC format described in the CRC Handbook of Chemistry
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and Physics, 78th Edition, CRC Press, Boca Raton, Florida [1997]) and/or the
Lanthanide or Actinide series elements results in a catalyst composition with
an
enhanced olefin yield and/or a longer lifetime when used in the conversion of
feedstocks, such as oxygenates, more particularly methanol, into olefin(s). In
addition, the resultant catalyst composition tends to be more propylene
selective
and to yield lower amounts of unwanted ethane and propane, together with other
undesirable compounds, such as aldehydes and ketones, specifically
acetaldehyde.
Molecular Sieves
[0023] Molecular sieves have been classified by the Structure Commission
of the International Zeolite Association according to the rules of the IUPAC
Commission on Zeolite Nomenclature. According to this classification,
framework-type zeolite and zeolite-type molecular sieves, for which a
structure
has been established, are assigned a three letter code and are described in
the Atlas
of Zeolite Framework Types, 5th edition, Elsevier, London, England (2001).
[0024] Non-limiting examples of preferred molecular sieves, particularly for
use in converting an oxygenate containing feedstock into olefin(s), include
framework types AEL, AEI, BEA, CHA, EDI, FAU, FER, GIS, LTA, LTL, MER,
MFI, MOR, MTT, MWW, TAM and TON. In one preferred embodiment, the
molecular sieve employed in the catalyst composition of the invention has an
AEI
topology or a CHA topology, or a combination thereof, most preferably a CHA
topology.
[0025] Crystalline molecular sieve materials have a 3-dimensional, four-
connected framework structure of comer-sharing [TO4] tetrahedra, where T is
any
tetrahedrally coordinated cation, such as [SiO4], [A1O4] and/or [PO4]
tetrahedral
units. The molecular sieves useful herein conveniently comprise a framework
including [Al04] and [PO4] tetrahedral units, i.e., an aluminophosphate (A1PO)
molecular sieve, or [SiO4], [A1O4] and [P04] ] tetrahedral units, i.e., a
silicoaluminophosphate (SAPO) molecular sieve. Most preferably, the molecular
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sieves useful herein is a silicoaluminophosphate (SAPO) molecular sieve or a
substituted, preferably a metal substituted, SAPO molecular sieve. Examples of
suitable metal substituents are an alkali metal of Group 1 of the Periodic
Table of
Elements, an alkaline earth metal of Group 2 of the Periodic Table of
Elements, a
rare earth metal of Group 3 of the Periodic Table of Elements, including the
Lanthanides lanthanum, cerium, praseodymium, neodymium, samarium,
europium, gadolinium, erbium, dysprosium, holmium, erbium, thulium, ytterbium
and lutetium; and scandium or yttrium, a transition metal of Groups 4 to 12 of
the
Periodic Table of Elements, or mixtures of any of these metal species.
[00261 Preferably, the molecular sieve used herein has a pore systenm
defined by an 8-membered ring of [TO4] tetrahedra and has an average pore size
less than 5A, such as in the range of from 3A to 5A, for example from 3A to
4.5A,
and particularly from 3.5A to 4.2A.
[00271 Non-limiting examples of SAPO and A1PO molecular sieves useful
herein include one or a combination of SAPO-5, SAPO-8, SAPO-11, SAPO-16,
SAPO-17, SAPO-18, SAPO-20, SAPO-31, SAPO-34, SAPO-35, SAPO-36,
SAPO-37, SAPO-40, SAPO-41, SAPO-42, SAPO-44 (U.S. Patent No. 6,162,415),
SAPO-47, SAPO-56, ALPO-5, ALPO-11, A1PO-18, ALPO-31, AIPO-34, AIPO-36,
ALPO-37, A1PO-46, and metal containing molecular sieves thereof. Of these,
particularly useful molecular sieves are one or a combination of SAPO-18, SAPO-
34, SAPO-35, SAPO-44, SAPO-56, AIPO-18 and AIPO-34 and metal containing
derivatives thereof, such as one or a combination of SAPO-18, SAPO-34, A1PO-
34 and ALPO-18, and metal containing derivatives thereof, and especially one
or a
combination of SAPO-34 and AIPO-18, and metal containing derivatives thereof.
[0028] In an embodiment, the molecular sieve is an intergrowth material
having two or more distinct crystalline phases within one molecular sieve
composition. In particular, intergrowth molecular sieves are described in the
U.S.
Patent Application Publication No. 2002-0165089 and International Publication
No. WO 98/15496 published April 16, 1998. For example, SAPO-18, AlPO-18
and RUW- 18 have
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an AEI framework-type, and SAPO-34 has a CHA framework-type. Thus the
molecular sieve used herein may comprise at least one intergrowth phase of AEI
and CHA framework-types, especially where the ratio of CHA framework-type to
AEI framework-type, as determined by the DIFFaX method disclosed in U.S.
Patent Application Publication No. 2002-0165089, is greater than 1:1.
[0029] Preferably, where the molecular sieve is a silicoaluminophosphate,
the molecular sieve has a Si/Al ratio less than or equal to 0.65, such as from
0.65
to 0.10, preferably from 0.40 to 0.10, more preferably from 0.32 to 0.10, and
most
preferably from 0.32 to 0.15.
Metal Oxides
[0030] The metal oxides useful herein are oxides of Group 3 metals and the
Lanthanide and Actinide series metals which have an uptake of carbon dioxide
at
100 C of at least 0.03 mg/m2 of the metal oxide, such as at least 0.04 mg/m2
of the
metal oxide. Although the upper limit on the carbon dioxide uptake of the
metal
oxide is not critical, in general the metal oxides useful herein will have a
carbon
dioxide at 100 C of less than 10 mg/m2 of the metal oxide, such as less than 5
mg/m2 of the metal oxide. Typically, the metal oxides useful herein have a
carbon
dioxide uptake of 0.05 to 1 mg/m2 of the metal oxide. When used in combination
with a molecular sieve, such active metal oxides provide benefits in catalytic
conversion processes, particularly the conversion of oxygenates to olefins.
[0031] In order to determine the carbon dioxide uptake of a metal oxide, the
following procedure is adopted. A sample of the metal oxide is dehydrated by
heating the sample to about 200 C to 500 C in flowing air until a constant
weight,
the "dry weight", is obtained. The temperature of the sample is then reduced
to
100 C and carbon dioxide is passed over the sample, either continuously or in
pulses, again until constant weight is obtained. The increase in weight of the
sample in terms of mg/mg of the sample based on the dry weight of the sample
is
the amount of adsorbed carbon dioxide.
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[0032] In the Examples reported below, the carbon dioxide adsorption is
measured using a Mettler TGA/SDTA 851 thermogravimetric analysis system
under ambient pressure. The metal oxide sample is dehydrated in flowing air to
about 500 C for one hour. The temperature of the sample is then reduced in
flowing helium to the desired adsorption temperature of 100 C. After the
sample
has equilibrated at 100 C in flowing helium, the sample is subjected to 20
separate
pulses (about 12 seconds/pulse) of a gaseous mixture comprising 10 weight %
carbon dioxide with the remainder being helium. After each pulse of the
adsorbing gas the metal oxide sample is flushed with flowing helium for 3
minutes. The increase in weight of the sample in terms of mg/mg adsorbent
based
on the adsorbent weight after treatment at 500 C is the amount of adsorbed
carbon
dioxide. The surface area of the sample is measured in accordance with the
method of Brunauer, Emmett, and Teller (BET) published as ASTM D 3663 to
provide the carbon dioxide uptake in terms of mg carbon dioxide/m2 of the
metal
oxide.
[0033] Preferred Group 3 metal oxides include oxides of scandium, yttrium
and lanthanum, and preferred oxides of the Lanthanide or Actinide series
metals
include oxides of cerium, praseodymium, neodymium, samarium, europium,
gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium
and thorium. The most preferred active metal oxides are scandium oxide,
lanthanum oxide, yttrium oxide, cerium oxide, praseodymium oxide, neodymium
oxide and mixtures thereof, particularly mixtures of lanthanum oxide and
cerium
oxide.
[0034] In one embodiment, useful metal oxides are those oxides of Group 3
metals and/or the Lanthanide and Actinide series metals that, when used in
combination with a molecular sieve in a catalyst composition, are effective in
extending of the useful life of the catalyst composition. Quantification of
the
extension in the catalyst composition life is determined by the Lifetime
Enhancement Index (LEI) as defined by the following equation:
LEI = Lifetime of Catalyst in Combination with Active Metal Oxide(s) where
Lifetime of Catalyst
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the lifetime of the catalyst or catalyst composition, is measured in the same
process under the same conditions, and is the cumulative amount of feedstock
processed per gram of catalyst composition until the conversion of feedstock
by
the catalyst composition falls below some defined level, for example 10%. An
inactive metal oxide will have little to no effect on the lifetime of the
catalyst
composition, or will shorten the lifetime of the catalyst composition, and
will
therefore have a LEI less than or equal to 1. Active metal oxides of the
invention
are those Group 3 metal oxides, including oxides of the Lanthanide and
Actinide
series, that when used in combination with a molecular sieve, provide a
molecular
sieve catalyst composition that has a LEI greater than 1. By definition, a
molecular sieve catalyst composition that has not been combined with an active
metal oxide will have a LEI equal to 1Ø
[0035] It is found that, by including an active metal oxide in combination
with a molecular sieve, a catalyst composition can be produced having an LEI
in
the range of from greater than 1 to 50, such as from 1.5 to 20. Typically
catalyst
compositions according to the invention exhibit LEI values greater than 1.1,
for
example in the range of from 1.2 to 15, and more particularly greater than
1.3,
such as greater than 1.5, such as greater than 1.7, such as greater than 2.
[0036] The active metal oxide(s) can be prepared using a variety of methods.
It is preferable that the active metal oxide is made from an active metal
oxide
precursor, such as a metal salt, such as a nitrate, halide, nitrate sulfate or
acetate.
Other suitable sources of the metal oxide include compounds that form the
metal
oxide during calcination, such as oxychlorides and nitrates. Alkoxides are
also
suitable sources of the Group 3 metal oxide, for example yttrium n-propoxide.
[0037] In one embodiment, the Group 3 metal oxide or oxide of the
Lanthanide or Actinide series is hydrothermally treated under conditions that
include a temperature of at least 80 C, preferably at least 100 C. The
hydrothermal treatment may take place in a sealed vessel at greater than
atmospheric pressure. However, a preferred mode of treatment involves the use
of
an open vessel under reflux conditions. Agitation of the Group 3 metal oxide
or
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the oxide of the Lanthanide or Actinide series in a liquid medium, for
example, by
the action of refluxing liquid and/or stirring, promotes the effective
interaction of
the oxide with the liquid medium. The duration of the contact of the oxide
with
the liquid medium is preferably at least 1 hour, preferably at least 8 hours.
The
liquid medium for this treatment preferably has a pH of about 6 or greater,
preferably 8 or greater. Non-limiting examples of suitable liquid media
include
water, hydroxide solutions (including hydroxides of NH4, Na+, K, Mg", and
Cat'), carbonate and bicarbonate solutions (including carbonates and
bicarbonates
of NH4, Nat, K+, Mgz+, and Caz+), pyridine and its derivatives, and
alkyl/hydroxyl
amines.
[0038] In another embodiment, the active Group 3 metal oxide or the active
oxide of the Lanthanide or Actinide series is prepared by subjecting a liquid
solution, such as an aqueous solution, comprising a source of ions of the
metal,
such as a metal salt, to conditions sufficient to cause precipitation of a
hydrated
precursor to the solid oxide material, such as by the addition of a
precipitating
reagent to the solution. Conveniently, the precipitation is conducted at a pH
above
7. For example, the precipitating agent preferably is a base such as sodium
hydroxide or ammonium hydroxide.
[0039] The temperature at which the liquid medium is maintained during the
precipitation is generally less than or equal to 200 C, such in the range of
from
0 C to 200 C. A particular range of temperatures for precipitation is from 20
C to
100 C. The resulting gel is preferably then hydrothermally treated at
temperatures
of at least 80 C, preferably at least 100 C. The hydrothermal treatment
typically
takes place at atmospheric pressure. The gel, in one embodiment, is
hydrothermally treated for up to 10 days, such as up to 5 days, for example up
to 3
days.
[0040] The hydrated precursor to the metal oxide(s) is then recovered, for
example by filtration or centrifugation, and washed and dried. The resulting
material can then be calcined, such as in an oxidizing atmosphere, at a
temperature
of at least 400 C, such as at least 500 C, for example from 600 C to 900 C,
and
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particularly from 650 C to 800 C, to form the solid oxide material. The
calcination time is typically up to 48 hours, such as for 0.5 to 24 hours, for
example for 1.0 to 10 hours. In one embodiment, calcination is carried out at
about 700 C for 1 to 3 hours.
Catalyst Composition
[0041] The catalyst composition of the invention includes any one of the
molecular sieves previously described and one or more of the active metal
oxides
described above, optionally with a binder and/or matrix material different
from the
active metal oxide(s). Typically, the weight ratio of the molecular sieve to
the
active metal oxide in the catalyst composition is in the range of from 5
weight
percent to 800 weight percent, preferably from 10 weight percent to 600 weight
percent, more preferably from 20 weight percent to 500 weight percent, and
most
preferably from 30 weight percent to 400 weight percent.
[0042] There are many different binders that are useful in forming the
catalyst composition of the invention. Non-limiting examples of binders that
are
useful alone or in combination include various types of hydrated alumina,
silicas,
and/or other inorganic oxide sols. One preferred alumina containing sol is
aluminum chlorhydrol. The inorganic oxide sol acts like glue binding the
synthesized molecular sieves and other materials such as the matrix together,
particularly after thermal treatment. Upon heating, the inorganic oxide sol,
preferably having a low viscosity, is converted into an inorganic oxide binder
component. For example, an alumina sol will convert to an aluminum oxide
binder following heat treatment.
[0043] Aluminum chlorhydrol, a hydroxylated aluminum based sol
containing a chloride counter ion, has the general formula of
AlmOn(OH)oClp x(H2O) wherein m is 1 to 20, n is 1 to 8, o is 5 to 40, p is 2
to 15,
and x is 0 to 30. In one embodiment, the binder is A11304(OH)24C17.12(H20) as
is
described in G.M. Wolterman, et al., Stud. Surf. Sci. and Catal., 76, pages
105-
144 (1993). In another embodiment, one or more binders are combined with one
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or more other alumina materials such as aluminum oxyhydroxide, y-alumina,
boehmite, diaspore, and transitional aluminas such as a-alumina, R-alumina, y-
alumina, 6-alumina, c-alumina, x-alumina, and p-alumina, aluminum
trihydroxide,
such as gibbsite, bayerite, nordstrandite, doyelite, and mixtures thereof.
[0044] Non-limiting examples of commercially available colloidal alumina
TM
sols include Nalco 8676 available from Nalco Chemical Co., Naperville,
Illinois,
TM
and Nyacol AL20DW available from Nyacol Nano Technologies, Inc., Ashland,
Massachussetts.
[0045] Where the catalyst composition contains a matrix material, this is
preferably different from the active metal oxide and any binder. Matrix
materials
are typically effective in reducing overall catalyst cost, acting as thermal
sinks
during regeneration, densifying the catalyst composition, and increasing
catalyst
physical properties such as crush strength and attrition resistance.
[0046] Non-limiting examples of matrix materials useful herein include one
or more non-active metal oxides including beryllia, quartz, silica or sols,
and
mixtures thereof, for example silica-magnesia, silica-zirconia, silica-
titania, silica-
alumina and silica-alumina-thoria. In an embodiment, matrix materials are
natural
clays such as those from the families of montmorillonite and kaolin. These
natural clays include subbentonites and those kaolins known as, for example,
Dixie, McNamee, Georgia and Florida clays. Non-limiting examples of other
matrix materials include haloysite, kaolinite, dickite, nacrite, or anauxite.
The
matrix material, such as a clay, may be subjected to well known modification
processes such as calcination and/or acid treatment and/or chemical treatment.
[0047] In a preferred embodiment, the matrix material is a clay or a clay-
type composition, particularly having a low iron or titanic content, and most
preferably is kaolin. Kaolin has been found to form a pumpable, high solids
content slurry, to have a low fresh surface area, and to pack together easily
due to
its platelet structure. A preferred average particle size of the matrix
material, most
preferably kaolin, is from 0.1 p.m to 0.6 pm with a D90 particle size
distribution of
less than 1 m.
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[0048] Where the catalyst composition contains a binder or matrix material,
the catalyst composition typically contains from 1% to 80%, preferably from
about 5% to 60%, and more preferably from 5% to 50%, by weight of the
molecular sieve based on the total weight of the catalyst composition.
[0049] Where the catalyst composition contains a binder and a matrix
material, the weight ratio of the binder to the matrix material is typically
from
1:15 to 1:5, such as from 1:10 to 1:4, and particularly from 1:6 to 1:5. The
amount of binder is typically from about 2% by weight to about 30% by weight,
such as from about 5% by weight to about 20% by weight, and particularly from
about 7% by weight to about 15% by weight, based on the total weight of the
binder, the molecular sieve and matrix material.
[0050] The catalyst composition typically has a density in the range of from
0.5 g/cc to 5 g/cc, such as from from 0.6 g/cc to 5 g/cc, for example from 0.7
g/cc
to 4 g/cc, particularly in the range of from 0.8 g/cc to 3 g/cc.
Catalyst Composition Formulation
[0051] In making the catalyst composition, the molecular sieve is first
synthesized and is then physically mixed with the active metal oxide,
preferably in
a substantially dry, dried, or calcined state. Most preferably the molecular
sieve
and active metal oxide are physically mixed in their calcined state. Intimate
physical mixing can be achieved by any method known in the art, such as mixing
with a mixer muller, drum mixer, ribbon/paddle blender, kneader, or the like.
Chemical reaction between the molecular sieve and the metal oxide(s) is
unnecessary and, in general, is not preferred.
[0052] Where the catalyst composition contains a matrix and/or binder, the
molecular sieve is conveniently initially formulated into a catalyst precursor
with
the matrix and/or binder and the active metal oxide is then combined with the
formulated precursor. The active metal oxide can be added as unsupported
particles or can be added in combination with a support, such as a binder or
matrix
material. The resultant catalyst composition can then be formed into useful
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shaped and sized particles by well-known techniques such as spray drying,
pelletizing, extrusion, and the like.
[0053] In one embodiment, the molecular sieve composition and the matrix
material, optionally with a binder, are combined with a liquid to form a
slurry and
then mixed to produce a substantially homogeneous mixture containing the
molecular sieve composition. Non-limiting examples of suitable liquids include
water, alcohol, ketones, aldehydes, and/or esters. The most preferred liquid
is
water. The slurry of the molecular sieve composition, binder and matrix
material
is then fed to a forming unit, such as spray drier, that forms the catalyst
composition into the required shape, for example microspheres.
[0054] Once the molecular sieve catalyst composition is formed in a
substantially dry or dried state, to further harden and/or activate the formed
catalyst composition, a heat treatment such as calcination is usually
performed.
Typical calcination temperatures are in the range from 400 C to 1,000 C,
preferably from 500 C to 800 C and more preferably from 550 C to 700 C.
Typical calcination environments are air (which may include a small amount of
water vapor), nitrogen, helium, flue gas (combustion product lean in oxygen),
or
any combination thereof.
[0055] In a preferred embodiment, the catalyst composition is heated in
nitrogen at a temperature of from 600 C to 700 C for a period of time
typically
from 30 minutes to 15 hours, preferably from 1 hour to about 10 hours, more
preferably from about 1 hour to about 5 hours, and most preferably from about
2
hours to about 4 hours.
Use of Catalyst Composition
[0056] The catalyst composition described above is useful in a variety of
processes including cracking, of for example a naphtha feed to light olefin(s)
(U.S.
Patent No. 6,300,537) or higher molecular weight (MW) hydrocarbons to lower
MW hydrocarbons; hydrocracking, of for example heavy petroleum and/or cyclic
feedstock; isomerization, of for example aromatics such as xylene;
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polymerization, of for example one or more olefin(s) to produce a polymer
product; reforming; hydrogenation; dehydrogenation; dewaxing, of for example
hydrocarbons to remove straight chain paraffins; absorption, of for example
alkyl
aromatic compounds for separating out isomers thereof; alkylation, of for
example
aromatic hydrocarbons such as benzene and alkylbenzenes; transalkylation, of
for
example a combination of aromatic and polyalkylaromatic hydrocarbons;
dealkylation; hydrodecylization; disproportionation, of for example toluene to
make benzene and xylenes; oligomerization, of for example straight and
branched
chain olefin(s); and dehydrocyclization.
[0057] Preferred processes include processes for converting naphtha to
highly aromatic mixtures; converting light olefin(s) to gasoline, distillates
and
lubricants; converting oxygenates to olefin(s); converting light paraffins to
olefins
and/or aromatics; and converting unsaturated hydrocarbons (ethylene and/or
acetylene) to aldehydes for conversion into alcohols, acids and esters.
[0058] The most preferred process of the invention is the conversion of a
feedstock to one or more olefin(s). Typically, the feedstock contains one or
more
aliphatic-containing compounds, and preferably one or more oxygenates, such
that
the aliphatic moiety contains from 1 to about 50 carbon atoms, preferably from
1
to 20 carbon atoms, more preferably from 1 to 10 carbon atoms, and most
preferably from 1 to 4 carbon atoms.
[0059] Non-limiting examples of suitable aliphatic-containing compounds
include alcohols such as methanol and ethanol, alkyl mercaptans such as methyl
mercaptan and ethyl mercaptan, alkyl sulfides such as methyl sulfide,
alkylamines
such as methylamine, alkyl ethers such as dimethyl ether, diethyl ether and
methylethyl ether, alkyl halides such as methyl chloride and ethyl chloride,
alkyl
ketones such as dimethyl ketone, formaldehydes, and various acids such as
acetic
acid. Preferably, the feedstock comprises methanol, ethanol, dimethyl ether,
diethyl ether or a combination thereof, more preferably methanol and/or
dimethyl
ether, and most preferably methanol.
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[0060] Using the various feedstocks discussed above, particularly a
feedstock containing an oxygenate, such as an alcohol, the catalyst
composition of
the invention is effective to convert the feedstock primarily into one or more
olefin(s). The olefin(s) produced typically have from 2 to 30 carbon atoms,
preferably 2 to 8 carbon atoms, more preferably 2 to 6 carbon atoms, still
more
preferably 2 to 4 carbons atoms, and most preferably are ethylene and/or
propylene.
[0061] Typically, the catalyst composition of the invention is effective to
convert a feedstock containing one or more oxygenates into a product
containing
greater than 50 weight percent, typically greater than 60 weight percent, such
as
greater than 70 weight percent, and preferably greater than 80 weight percent
of
olefin(s) based on the total weight of hydrocarbon in the product. Moreover,
the
amount of ethylene and/or propylene produced based on the total weight of
hydrocarbon in the product is typically greater than 40 weight percent, for
example greater than 50 weight percent, preferably greater than 65 weight
percent,
and more preferably greater than 78 weight percent. Typically, the amount
ethylene produced in weight percent based on the total weight of hydrocarbon
product produced, is greater than 30 weight percent, such as greater than 35
weight percent, for example greater than 40 weight percent. In addition, the
amount of propylene produced in weight percent based on the total weight of
hydrocarbon product produced is greater than 20 weight percent, such as
greater
than 25 weight percent, for example greater than 30 weight percent, and
preferably
greater than 35 weight percent.
[0062] Using the catalyst composition of the invention for the conversion of
a feedstock comprising methanol and dimethylether to ethylene and propylene,
it
is found that the production of ethane and propane is reduced by greater than
10%,
such as greater than 20%, for example greater than 30%, and particularly in
the
range of from 30% to 40% compared to a similar catalyst composition at the
same
conversion conditions but without the active metal oxide component(s).
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[0063] In addition to the oxygenate component, such as methanol, the
feedstock may contain one or more diluents, which are generally non-reactive
to
the feedstock or molecular sieve catalyst composition and are typically used
to
reduce the concentration of the feedstock. Non-limiting examples of diluents
include helium, argon, nitrogen, carbon monoxide, carbon dioxide, water,
essentially non-reactive paraffins (especially alkanes such as methane,
ethane, and
propane), essentially non-reactive aromatic compounds, and mixtures thereof.
The most preferred diluents are water and nitrogen, with water being
particularly
preferred.
[0064] The present process can be conducted over a wide range of
temperatures, such as in the range of from 200 C to 1000 C, for example from
250 C to 800 C, including from 250 C to 750 C, conveniently from 300 C to
650 C, preferably from 350 C to 600 C and more preferably from 350 C to
550 C.
[0065] Similarly, the present process can be conducted over a wide range of
pressures including autogenous pressure. Typically the partial pressure of the
feedstock exclusive of any diluent therein employed in the process is in the
range
of from 0.1 kPaa to 5 MPaa, preferably from 5 kPaa to 1 MPaa, and more
preferably from 20 kPaa to 500 kPaa.
[0066] The weight hourly space velocity (WHSV), defined as the total
weight of feedstock excluding any diluents per hour per weight of molecular
sieve
in the catalyst composition, can range from 1 hr"' to 5000 hf', preferably
from 2
hr"' to 3000 hr"', more preferably from 5 hr"' to 1500 hf', and most
preferably from
hr"' to 1000 hr"'. In one embodiment, the WHSV is at least 20 hr"' and, where
the feedstock contains methanol and/or dimethyl ether, is in the range of from
20
hr"' to 300 hr"'.
[0067] The process of the invention is conveniently conducted as a fixed bed
process, or more typically as a fluidized bed process (including a turbulent
bed
process), such as a continuous fluidized bed process, and particularly a
continuous
high velocity fluidized bed process.
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[0068] In one practical embodiment, the process is conducted as a fluidized
bed process utilizing a reactor system, a regeneration system and a recovery
system. In such a process, fresh feedstock, optionally with one or more
diluent(s),
is fed together with the molecular sieve catalyst composition into one or more
riser reactor(s) in the reactor system. The feedstock is converted in the
riser
reactor(s) into a gaseous effluent that enters a disengaging vessel in the
reactor
system along with the coked catalyst composition. The coked catalyst
composition is separated from the gaseous effluent within the disengaging
vessel,
typically with the aid of cyclones, and is then fed to a stripping zone,
typically in a
lower portion of the disengaging vessel. In the stripping zone the coked
catalyst
composition is contacted with a gas, such steam, methane, carbon dioxide,
carbon
monoxide, hydrogen, and/or an inert gas such as argon, preferably steam, to
recover adsorbed hydrocarbons from the coked catalyst composition that is then
introduced into the regeneration system.
[0069] In the regeneration system the coked catalyst composition is
contacted with a regeneration medium, preferably a gas containing oxygen,
under
regeneration conditions capable of burning coke from the coked catalyst
composition, preferably to a level less than 0.5 weight percent based on the
total
weight of the coked molecular sieve catalyst composition entering the
regeneration system. For example, the regeneration conditions may include
temperature in the range of from 450 C to 750 C, and preferably from 550 C to
700 C.
[0070] The regenerated catalyst composition withdrawn from the
regeneration system is combined with fresh molecular sieve catalyst
composition
and/or re-circulated molecular sieve catalyst composition and/or feedstock
and/or
fresh gas or liquids, and returned to the riser reactor(s).
[0071] The gaseous effluent is withdrawn from the disengaging system and
is passed through a recovery system for separating and purifying the light
olefin(s), particularly ethylene and propylene, in the gaseous effluent.
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[0072] In one practical embodiment, the process of the invention forms part
of an integrated process for producing light olefin(s) from a hydrocarbon
feedstock, particularly methane and/or ethane. The first step in the process
is
passing the gaseous feedstock, preferably in combination with a water stream,
to a
syngas production zone to produce a synthesis gas stream, typically comprising
carbon dioxide, carbon monoxide and hydrogen. The synthesis gas stream is then
converted to an oxygenate containing stream generally by contacting with a
heterogeneous catalyst, typically a copper based catalyst, at temperature in
the
range of from 150 C to 450 C and a pressure in the range of from 5 MPa to 10
MPa. After purification, the oxygenate containing stream can be used as a
feedstock in a process as described above for producing light olefin(s), such
as
ethylene and/or propylene. Non-limiting examples of this integrated 'process
are
described in EP-B-0 933 345,
[0073] In another more fully integrated process, optionally combined with
the integrated processes described above, the olefin(s) produced are directed
to
one or more polymerization processes for producing various polyolefms.
[0074] In order to provide a better understanding of the present invention
including representative advantages thereof, the following Examples are
offered..
[0075] In the Examples, LEI is defined as the ratio of the lifetime of a
molecular sieve catalyst composition containing an active metal oxide(s)
compared to that of the same molecular sieve in the absence of a metal oxide,
defined as having an LEI of 1. For the purpose of determining LEI, lifetime is
defined as the cumulative amount of oxygenate converted, preferably into one
or
more olefin(s), per gram of molecular sieve, until the conversion rate drops
to
about 10% of its initial value. If the conversion has not fallen to 10% of its
initial
value by the end of the experiment, lifetime is estimated by linear
extrapolation
based on the rate of decrease in conversion over the last two data points in
the
experiment.
[0076] "Prime Olefin" is the sum of the selectivity to ethylene and
propylene. The ratio "CZ /C3' is the ratio of the ethylene to propylene
selectivity
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weighted over the run. The "C3 Purity" is calculated by dividing the propylene
selectivity by the sum of the propylene and propane selectivities. The
selectivities
for methane, ethylene, ethane, propylene, propane, C4's and C5+'s are average
selectivities weighted over the run. Note that the C5+'s consist only of C5's,
C6 'S
and C; s. The selectivity values do not sum to 100% in the Tables because they
have been corrected for coke as is well known.
Example A
Preparation of Molecular Sieve
[0077] A silicoaluminophosphate molecular sieve, SAPO-34, designated as
MSA, was crystallized in the presence of tetraethyl ammonium hydroxide (Ri)
and dipropylamine (R2) as the organic structure directing agents or templating
agents. A mixture of the following mole ratio composition:
0.2 S'02/A1203/P205/0.9 RI / 1.5 R2/50H20.
was prepared by initially mixing an amount of Condea Pural SB with deionised
water, to form a slurry. To this slurry was added an amount of phosphoric acid
(85%). These additions were made with stirring to form a homogeneous mixture.
TM
To this homogeneous mixture Ludox AS40 (40% of SiO2) was added, followed.
by the addition of Rl with mixing to form a homogeneous mixture. To this
homogeneous mixture R2 was added and the resultant mixture was then
crystallized with agitation in a stainless steel autoclave by heating to 170 C
for 40
hours. This provided a slurry of the crystalline molecular sieve. The crystals
were
then separated from the mother liquor by filtration. The molecular sieve
crystals
were then mixed with a binder and matrix material and formed into particles by
spray drying.
Example B
Conversion Process
[0078] All conversion data presented were obtained using a microflow
reactor consisting of a stainless steel reactor (1/4 inch (0.64 cm) outer
diameter)
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located in a furnace to which vaporized methanol was fed. The reactor was
maintained at a temperature of 475 C and a pressure of 25 psig (172.4 kPag)
The
flow rate of the methanol was such that the flow rate of methanol on weight
basis
per gram of molecular sieve, also known as the weight hourly space velocity
(WHSV) was 100 h''. Product gases exiting the reactor were collected and
analyzed using gas chromatography. The catalyst load was 50 mg and the
catalyst
bed was diluted with quartz to minimize hot spots in the reactor.
Example 1
[0079] A sample of La(N03)3.xH20 (Aldrich Chemical Company) was
calcined in air at 700 C for 3 hours to produce lanthanum oxide.
Example 2
[0080] Fifty grams of La(N03)3-xH2O (Aldrich Chemical Company) were
dissolved with stirring in 500ml of distilled water. The pH was adjusted to 9
by
the addition of concentrated ammonium hydroxide. This slurry was then put in
polypropylene bottles and placed in a steambox (100 C) for 72 hours. The
product formed was recovered by filtration, washed with excess water, and
dried,
overnight at 85 C. A portion of this catalyst was calcined to 600 C in flowing
air
for 3 hours to produce lanthanum oxide (La203).
Example 3
[0081] Fifty grams of Y(NO3)3.6H2O were dissolved with stirring in 500m1
of distilled water. The pH was adjusted to 9 by the addition of concentrated
ammonium hydroxide. This slurry was then put in polypropylene bottles and
placed in a steambox (100 C) for 72 hours. The product formed was recovered by
filtration, washed with excess water, and dried overnight at 85 C. A portion
of
this catalyst was calcined to 600 C in flowing air for 3 hours to produce
yttrium
oxide (Y203).
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Example 4
[0082] A sample of Sc(N03)3.xH2O (Aldrich Chemical Company) was
calcined in air at 700 C for 3 hours to produce scandium oxide (Sc203).
Example 5
[0083] Fifty grams of Ce(N03)3.6H20 were dissolved with stirring in 500m1
of distilled water. The pH was adjusted to 8 by the addition of concentrated
ammonium hydroxide. This slurry was then put in polypropylene bottles and
placed in a steambox (100 C) for 72 hours. The product formed was recovered by
filtration, washed with excess water, and dried overnight at 85 C. A portion
of
this catalyst was calcined to 600 C in flowing air for 3 hours to produce
cerium
oxide (Ce203).
Example 6
[0084] Fifty grams of Pr(N03)3.6H20 were dissolved with stirring in 500m1
of distilled water. The pH was adjusted to 8 by the addition of concentrated
ammonium hydroxide. This slurry was then put in polypropylene bottles and
placed in a steambox (100 C) for 72 hours. The product formed was recovered by
filtration, washed with excess water, and dried overnight at 85 C. A portion
of
this catalyst was calcined to 600 C in flowing air for 3 hours to produce
praseodymium oxide (Pr203).
Example 7
[0085] Fifty grams of Nd(N03)3.6H20 were dissolved with stirring in 500ml
of distilled water. The pH was adjusted to 9 by the addition of concentrated
ammonium hydroxide. This slurry was then put in polypropylene bottles and
placed in a steambox (100 C) for 72 hours. The product formed was recovered by
filtration, washed with excess water, and dried overnight at 85 C. A portion
of
this catalyst was calcined to 600 C in flowing air for 3 hours to produce
neodymium oxide (Nd203).
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Example 8
[0086] Thirty nine grams of Ce(N03)3.6H2O and 7.0 grams of
La(N03)3.6H20 were dissolved with stirring in 500m1 of distilled water.
Another
solution containing 20 grams of concentrated ammonium hydroxide and 500m1 of
distilled water was prepared. These two solutions were combined at the rate of
50m1/min using a nozzle mixer. The pH of the final composite was adjusted to
approximately 9 by the addition of concentrated ammonium hydroxide. This
slurry was then put in polypropylene bottles and placed in a steambox (100 C)
for
72 hours. The product formed was recovered by filtration, washed with excess
water, and dried overnight at 85 C. A portion of this catalyst was calcined to
700 C in flowing air for 3 hours to produce a mixed metal oxide containing a
nominal 5 weight percent lanthanum based on the final weight of the mixed
metal
oxide.
Example 9
[0087] Nine grams of Ce(N03)3.6H20 and 30.0 grams of La(N03)3.6H20
were dissolved with stirring in 500ml of distilled water. Another solution
containing 20 grams of concentrated ammonium hydroxide and 500ml of distilled
water was prepared. These two solutions were combined at the rate of 50m1/min
using a nozzle mixer. The,pH of the final composite was adjusted to
approximately 9 by the addition of concentrated ammonium hydroxide. This
slurry was then put in polypropylene bottles and placed in a steambox (100 C)
for
72 hours. The product formed was recovered by filtration, washed with excess
water, and dried overnight at 85 C. A portion of this catalyst was calcined to
700 C in flowing air for 3 hours to produce a mixed metal oxide containing a
nominal 5 weight percent cerium based on the final weight of the mixed metal
oxide.
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Example 10
[0088] The carbon dioxide uptake of the oxides of Examples 1 through 9
were measured using a Mettler TGA/SDTA 851 thermogravimetric analysis
system under ambient pressure. The metal oxide samples were first dehydrated
in
flowing air to about 500 C for one hour after which the uptake of carbon
dioxide
was measured at 100 C. The surface area of the samples were measured in
accordance with the method of Brunauer, Emmett, and Teller (BET) to provide
the
carbon dioxide uptake in terms of mg carbon dioxide/m2 of the metal oxide
presented in Table 1.
Table 1
Example Catalyst Dry CO2 Adsorbed Surface Area- CO2 Uptake
Weight (mg) (mg) (m2/g) (mg/m)
1 22 0.1846 40 0.210
2 31 0.6487 38 0.551
3 24 0.3296 80 0.172
4 20 0.0490 33 0.074
143 0.7714 57 0.095
6 50 0.3136 24 0.261
7 41 0.6491 18 0.880
8 130 0.8407 51 0.127
9 42 1.2542 46 0.649
Comparative Example 11
[0089] In this Comparative Example 11 (CEx. 11) the molecular sieve
catalyst composition produced in Example A was tested in the process of
Example
B using 50 mg of the molecular sieve catalyst composition without an active
metal
oxide. The results of the run are presented in Table 2 and Table 3.
Example 12
[0090] In this Example, the molecular sieve catalyst composition produced
in Example A was tested in the process of Example B using 40 mg of the
molecular sieve catalyst composition with 10 mg of La203 produced via nitrate
decomposition in Example 1. The components were well mixed and then diluted
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with sand to form the reactor bed. The results of this experiment are shown in
Tables 2 and 3 illustrating that the addition of La203, an active Group 3
metal
oxide, increased lifetime by 149%. Selectivity to ethane decreased by 36% and
selectivity to propane decreased by 32%, suggesting a significant reduction in
hydrogen transfer reactions.
Example 13
[00911 In this Example, the molecular sieve catalyst composition produced
in Example A was tested in the process of Example B using 40 mg of the
molecular sieve catalyst composition with 10 mg of La203 produced via
precipitation in Example 2. The components were well mixed and then diluted
with sand to form the reactor bed. The results of this experiment are shown in
Tables 2 and 3 illustrating that the addition of La203 produced via
precipitation, an
active Group 3 metal oxide, increased lifetime by 340%. Selectivity to ethane
decreased by 55% and selectivity to propane decreased by 44%, suggesting a
significant reduction in hydrogen transfer reactions.
Example 14
[00921 In this Example 14, the molecular sieve catalyst composition
produced in Example A was tested in the process of Example B using 40 mg of
the molecular sieve catalyst composition with 10 mg of Y203 produced in
Example
3. The components were well mixed and then diluted with sand to form the
reactor bed. The results of this experiment are shown in Tables 2 and 3
illustrating that the addition of Y203, an active Group 3 metal oxide,
increased
lifetime by 1090%. Selectivity to ethane decreased by 45% and selectivity to
propane decreased by 28%, suggesting a significant reduction in hydrogen
transfer
reactions.
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Example 15
[0093] In this Example 15, the molecular sieve catalyst composition
produced in Example A was tested in the process of Example B using 40 mg of
the molecular sieve catalyst composition with 10 mg of Sc203 produced in
Example 4. The components were well mixed and then diluted with sand to form
the reactor bed. The results of this experiment are shown in Tables 2 and 3
illustrating that the addition of Sc203, an active Group 3 metal oxide,
increased
lifetime by 167%. Selectivity to ethane decreased by 27% and selectivity to
propane decreased by 21 %, suggesting a significant reduction in hydrogen
transfer
reactions.
Example 16
[0094] In this Example 16, the molecular sieve catalyst composition
produced in Example A was tested in the process of Example B using 40 mg of
the molecular sieve catalyst composition with 10 mg of Ce203 produced in
Example 5. The components were well mixed and then diluted with sand to form
the reactor bed. The results of this experiment are shown in Tables 2 and 3
illustrating that the addition of Ce203, an active Lanthanide metal oxide,
increased
lifetime by 630%. Selectivity to ethane decreased by 50% and selectivity to
propane decreased by 34%, suggesting a significant reduction in hydrogen
transfer
reactions.
Example 17
[0095] In this Example 17, the molecular sieve catalyst composition
produced in Example A was tested in the process of Example B using 40 mg of
the molecular sieve catalyst composition with 10 mg of Pr203 produced in
Example 6. The components were well mixed and then diluted with sand to form
the reactor bed. The results of this experiment are shown in Tables 2 and 3
illustrating. that the addition of Pr203, an active Lanthanide metal oxide,
increased
lifetime by 640%. Selectivity to ethane decreased by 51% and selectivity to
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propane decreased by 38%, suggesting a significant reduction in hydrogen
transfer
reactions.
Example 18
[0096] In this Example 18, the molecular sieve catalyst composition
produced in Example A was tested in the process of Example B using 40 mg of
the molecular sieve catalyst composition with 10 mg of Nd203 produced in
Example 7. The components were well mixed and then diluted with sand to form
the reactor bed. The results of this experiment are shown in Tables 2 and 3
illustrating, that the addition of Nd203, an active Lanthanide metal oxide,
increased
lifetime by 340%. Selectivity to ethane decreased by 49% and selectivity to
propane decreased by 34%, suggesting a significant reduction in hydrogen
transfer
reactions.
Example 19
[0097] In this Example 19, the molecular sieve catalyst composition
produced in Example A was tested in the process of Example B using 40 mg of
the molecular sieve catalyst composition with 10 mg of the mixed metal oxide
produced in Example 8. The components were well mixed and then diluted with
sand to form the reactor bed. The results of this experiment are shown in
Tables 2
and 3 illustrating that the addition of 5% LaOX/Ce2O3, an active Lanthanide
metal
oxide modified by a Group 3 oxide, increased lifetime by 450%. Selectivity to
ethane decreased by 47% and selectivity to propane decreased by 37%,
suggesting
a significant reduction in hydrogen transfer reactions.
Example 20
[0098] In this Example 20, the molecular sieve catalyst composition
produced in Example A was tested in the process of Example B using 40 mg of
the molecular sieve catalyst composition with 10 mg of the mixed metal oxide
produced in Example 9. The components were well mixed and then diluted with
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sand to form the reactor bed. The results of this experiment are shown in
Tables 2
and 3 illustrating that the addition of 5% CeOX/La2O3, an active Group 3 metal
oxide modified by a Lanthanide series oxide, increased lifetime by 260%.
Selectivity to ethane decreased by 56% and selectivity to propane decreased by
45%, suggesting a significant reduction in hydrogen transfer reactions.
Table 2
Reactor Bed Lifetime Prime C2/C3 C3
Example Extension Olefin Purity
Composition -
Index (LEI) (%) (%)
CEx. 11 100%MSA 1.0 72.99 0.90 94.1
12 80% MSA / 20% La203 2.5 73.84 0.81 96.1
13 80% MSA / 20% La203 4.4 73.78 0.74 96.9
14 80% MSA / 20% Y203 11.9 73.68 0.76 96.0
15 80% MSA / 20% Sc203 2.7 73.74 0.81 95.5
16 80% MSA / 20% Ce203 7.3 70.51 0.69 96.3
17 80% MSA / 20% Pr203 7.4 72.37 0.72 96.6
18 80% MSA / 20% Nd2O3 4.4 72.57 0.71 96.3
19 80% MSA / 20% LaOX/Ce2O3 5.5 70.64 0.73 96.4
20 80% MSA / 20% CeO,,/La2O3 3.6 70.52 0.71 96.9
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Table 3
Reactor Bed CH
Example C2 C20 C3 C30 C4's C5+
Composition 4
CEx. 11 100%MSA 2.04 34.50 0.78 38.49 2.43 14.01 3.82
12 80% MSA / 20% La2O3 1.61 33.05 0.50 40.79 1.65 14.96 4.51
13 80% MSA / 20% La2O3 1.38 31.43 0.35 42.35 1.37 15.03 5.51
14 80% MSA / 20% Y2O3 1.39 31.85 0.43 41.83 1.74 14.43 5.61
15 80% MSA / 20% Sc2O3 1.67 33.08 0.57 40.66 1.93 14.49 4.45
16 80% MSA / 20% Ce2O3 2.05 28.89 0.39 41.62 1.61 15.29 6.83
17 80% MSA / 20% Pr2O3 1.59 30.18 0.38 42.19 1.51 15.22 6.06
18 80% MSA / 20% Nd2O3 1.64 30.2 0.40 42.37 1.61 15.13 5.68
19 80% MSA / 20% 2.62 29.85 0.41 40.80 1.52 14.07 7.14
LaO,,/Ce2O3
20 80% MSA / 20% 2.13 29.16 0.34 41.36 1.34 14.86 7.92
CeOX/La1O3
