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 Iight 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 olefm(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, ZKS, 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 olefins) from an alcohol using a crystalline aluminophosphate,
often designated AlPO4.
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[0005] Some of the most useful molecular sieves for converting methanol to
olefins) are silicoaluminophosphate (SAPO) molecular sieves.
Silicoaluminophosphate molecular sieves contain a three-dimensional
microporous crystalline framework structure of [SiOz], [A102] and [POZ] 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, all of
which are herein fully incorporated by reference.
[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,
Ba0 or Cs20 on microspherical non-porous silica, with Ba0 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 4 of the Periodic Table of Elements, wherein said metal oxide has an
uptake of carbon dioxide at 100°C of at least 0.03, and typically at
least 0.035,
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] The catalyst composition may also include an oxide of a metal
selected from Group 2 and Group 3 of the Periodic Table of Elements. In one
embodiment, the Group 4 metal oxide comprises zirconium oxide and the Group 2
and/or Group 3 metal oxide comprises one or more oxides selected from calcium
oxide, barium oxide, lanthanum oxide, yttrium oxide and scandium oxide.
[0016] Preferably, the molecular sieve conveniently comprises a
silicoaluminophosphate.
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[0017] In another aspect, the invention resides in a molecular sieve catalyst
composition comprising an active Group 4 metal oxide and a Group 2 and/or a
Group 3 metal oxide, a binder, a matrix material, and a
silicoaluuninophosphate
molecular sieve.
[0018) In yet another aspect, the invention resides in a method for making a
catalyst composition, the method comprising the step of physically mixing
first
particles comprising a molecular sieve with second particles comprising a
Group 4
metal oxide and having an uftake 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 said Group 4 metal oxide to precipitate from a solution
containing
ions of said 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 olefins) by converting a feedstock, such as an oxygenate,
conveniently
an alcohol, for example methanol, into one or more olefins) in the presence of
a
catalyst composition comprising a molecular sieve and an active Group 4 metal
oxide having an uptake of carbon dioxide at 100°C of at least 0.03
mg/m2 of the
metal oxide.
[0021] In still a further aspect, the invention is directed to a process for
converting a feedstock into one or more olefins) in the presence of a
molecular
sieve catalyst composition comprising a molecular sieve, a binder, a matrix
material and a mixture of metal oxides different from the binder and the
matrix
material.
[0022] 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.
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[0023] 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 one or more active metal oxides results in a catalyst
composition with 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 yield larger amounts of the desired
lower
olefins, especially propylene and lower amounts of unwanted ethane and
propane,
together with other undesirable compounds, such as aldehydes and ketones,
specifically acetaldehyde.
[0024] The preferred active metal oxides are those having a Group 4 metal
(for example zirconium and hafnium) from the Periodic Table of Elements using
the IUPAC format described in the CRC Handbook of Chemistry and Physics,
78th Edition, CRC Press, Boca Raton, Florida (1997). In some cases, it is
found
that improved results are obtained'when the catalyst composition also contains
at
least one oxide of a metal selected from Group 2 and/or Group 3 of the
Periodic
Table of Elements.
Molecular Sieves
[0025] 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),
which is herein fully incorporated by reference.
[0026] Non-limiting examples of preferred molecular sieves, particularly for
use in converting an oxygenate containing feedstock into olefm(s), include
framework types AEL, AFY, AEI, BEA, CHA, EDI, FAU, FER, GIS, LTA, LTL,
MER, MFI, MOR, MTT, MWW, TAM and TON. In one preferred embodiment,
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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.
[0027) Crystalline molecular sieve materials have a 3-dimensional, four-
connected framework structure of corner-sharing [T04] tetrahedra, where T is
any
tetrahedrally coordinated cation, such as [Si04], [A104] and/or [P04]
tetrahedral
units. The molecular sieves useful herein conveniently comprise a framework
including [AlO4] and [PO4] tetrahedral units, i.e., an aluminophosphate (A1P0)
molecular sieve, or [Si04], [A104] and [P04] ] tetrahedral units, i.e., a
silicoaluminophosphate (SAPO) molecular sieve. Most preferably, the molecular
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.
[002] Preferably, the molecular sieve used herein has a pore systenxn
defined by an 8-membered ring of [T04] tetrahedra and has an average pore size
less than S~, such as in the range of from 3A to SA, for example from 3~ to
4.SA,
and particularly from 3.SA to 4.2A.
[0029] Non-limiting examples of SAPO and A1P0 molecular sieves useful
herein include one or a combination of SAPO-S, SAPO-8, SAPO-11, SAPO-16,
SAPO-17, SAPO-18, SAPO-20, SAPO-31, SAPO-34, SAPO-3S, SAPO-36,
SAPO-37, SAPO-40, SAPO-41, SAPO-42, SAPO-44 (U.S. Patent No. 6,162,415),
SAPO-47, SAPO-S6, A1P0-S, A1P0-11, A1P0-18, A1P0-31, A1PO-34, A1P0-36,
A1P0-37, A1PO-46, and metal containing molecular sieves thereof. Of these,
particularly useful molecular sieves are one or a combination of SAPO-18, SAPO-
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34, SAPO-35, SAPO-44, SAPO-56, A1P0-18 and A1P0-34 and metal containing
derivatives thereof, such as one or a combination of SAPO-18, SAPO-34, A1P0-
34 and A1P0-18, and metal containing derivatives thereof, and especially one
or a
combination of SAPO-34 and A1P0-18, and metal containing derivatives thereof.
[0030] 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, both of which are herein fully
incorporated by reference. For example, SAPO-18, A1P0-18 and RUW-18 have
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.
[0031] 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.
Active Metal Oxides
[0032] Active metal oxides useful herein are those metal oxides, different
from typical binders and/or matrix materials, that, when used in combination
with
a molecular sieve, provide benefits in catalytic conversion processes.
Preferred
active metal oxides are those metal oxides having a Group 4 metal, such as
zirconium and/or hafnium, either alone or in combination with a Group 2 (for
example magnesium, calcium, strontium and barium) and/or a Group 3 metal
(including the Lanthanides and Actinides) oxide, (for example yttrium,
scandium
and lanthanum). The most preferred active Group 4 metal oxide is a zirconium
metal oxide, either alone or in combination with calcium oxide, barium oxide,
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lanthanum oxide and/or yttrium oxide.. In general, oxides of silicon,
aluminum,
and combinations thereof are not preferred.
[0033) In particular, active metal oxides are those metal oxides, different
from typical binders and/or matrix materials, 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, particularly in the conversion of a
feedstock
comprising methanol into one or more olefin(s). Quantification of the
extension
in catalyst 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
Lifetime of Catalyst
where the lifetime of the catalyst or catalyst composition, in the same
process
under the same conditions, 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. Thus active metal oxides of the invention are those
metal
oxides, different from typical binders and/or matrix materials, 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
[0034] 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 20, such as from 1.5 to 10. Typically
catalyst
compositions according to the invention exhibit LEI values greater than l.l,
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.
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[0035] In particular, the metal oxides useful herein have an uptake of carbon
dioxide at 100°C of at least 0.03 mg/m2 of the metal oxide, such as at
least 0.035
mg/mZ 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/mz of the metal
oxide, such as
less than 5 mg/mz of the metal oxide. Typically, the metal oxides useful
herein
have a carbon dioxide uptake of 0.04 to 0.2 mg/mz of the metal oxide.
[0036] 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 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.
[0037] In the Examples reported below, the carbon dioxide adsorption is
measured using a Mettler TGA/SDTA X51 thermogravimetric analysis system
under ambient pressure. The metal oxide sample is dehydrated in flowing air to
500°C for one hour. The temperature of the sample is then reduced in
flowing
helium to 100°C. After the sample has equilibrated at the desired
adsorption
temperature 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
caxbon
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.
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[003] Conveniently, the active metal oxides) has a BET surface area of
greater than 10 mz/g, such as greater than 10 m2/g to 300 mz/g. Preferably,
the
active metal oxides) has a BET surface area of at least 20 mz/g, such as from
20
m2/g to 250 m2/g. More preferably, the active metal oxides) has a BET surface
area of at Ieast 25 m2/g, such as from 25 m2/g to 200 m2/g. In a preferred
embodiment, the active metal oxides) includes a zirconium oxide having a BET
surface area greater than 20 mz/g, such as greater than 25 m2/g and
particularly
greater than 30 m2/g
[0039] The active metal oxides) 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 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 4 metal oxide, for example zirconium n-propoxide. A
preferred source of the Group 4 metal oxide is hydrated zirconia. The
expression,
hydrated zirconia, is intended to connote a material comprising zirconium
atoms
covalently linked to other zirconium atoms via bridging oxygen atoms, and
further
comprising available hydroxyl groups.
[0040] In one embodiment, the hydrated zirconia is hydrothermally treated
under conditions that include a temperature of at least 80°C,
preferably at least
100°C. The hydrothermal treatment typically takes 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
hydrated
Group 4 metal oxide in a liquid medium, for example, by the action of
refluxing
liquid and/or stirring, promotes the effective interaction of the hydrated
oxide with
the liquid medium. The duration of the contact of the hydrated oxide with the
liquid medium is conveniently at least 1 hour, such as at least 8 hours. The
liquid
medium for this treatment typically has a pH of about 6 or greater, such as 8
or
greater. Non-limiting examples of suitable liquid media include water,
hydroxide
solutions (including hydroxides of NH4'", Na+, I~+, Mgz+, and Caz~), carbonate
and
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bicarbonate solutions (including carbonates and bicarbonates of NH4+, Na+, ~+,
Mg2+, and Ca2+), pyridine and its derivatives, and alkyl/hydroxyl amines.
[0041] In another embodiment, the active metal oxide is prepared, for
example, by subjecting a liquid solution, such as an aqueous solution,
comprising
a source of ions of a Group 4 metal to conditions sufficient to cause
precipitation
of a hydrated precursor of 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 may be a base such as
sodium hydroxide or ammonium hydroxide.
[0042] When a mixture of a Group 4 metal oxide with a Group 2 and/or 3
metal oxide is to be prepared, a first liquid solution comprising a source of
ions of
a Group 4 metal can be combined with a second liquid solution comprising a
source of ions of a Group 2 and/or Group 3 metal. This combination of two
solutions can take place under conditions sufficient to cause co-precipitation
of a
hydrated precursor of the mixed oxide material as a solid from the solution.
Alternatively, the source of ions of the Group 4 metal and the source of ions
of the
Group 2 and/or Group 3 metal may be combined into a single solution. This
solution may then be subjected to conditions sufficient to cause co-
precipitation of
a hydrated precursor to the solid mixed oxide material, such as by the
addition of a
precipitating reagent to the solution.
[0043] The temperature at which the solution is maintained during the
precipitation is generally less than 200°C, for example in the range of
from 0°C to
less than 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.
[0044] The hydrated precursor to the metal oxides) is then recovered, for
example by filtration or centrifugation, and washed and dried. The resulting
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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
particularly from 650°C to 800°C, to form the active metal oxide
or active mixed
metal oxide. 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.
[0045] In another embodiment, the Group 4 metal oxide and the Group 2
and/or Group 3 metal oxide are made separately and then contacted together to
form the mixed metal oxide that is then contacted with the molecular sieve.
For
example, the Group 4 metal oxide can be contacted with the molecular sieve
prior
to introducing the Group 2 and/or Group 3 metal oxide or alternatively, the
Group
2 and/or Group 3 metal oxide can be contacted with the molecular sieve prior
to
introducing the Group 4 metal oxide.
[0046] Where the catalyst composition comprises a Group 4 metal oxide and
a Group 3 metal oxide, the mole ratio of the Group 4 metal oxide to the Group
3
metal oxide may be in the range of from 1000:1 to 1:1, such as from 500:1 to
2:1,
preferably from 100:1 to 3:1, more preferably from 75:1 to 5:1 based on the
total
moles of the Group 4 and Group 3 metal oxides. In addition, the catalyst
composition can contain from 1 to 25 %, preferably from 1 to 20 %, more
preferably from 1 to 15 %, by weight of Group 3 metal based on the total
weight
of the mixed metal oxide, particularly where the Group 3 metal oxide is a
lanthanum or yttrium metal oxide and the Group 4 metal oxide is a zirconium
metal oxide.
[0047] Where the catalyst composition comprises a Group 4 metal oxide and
a Group 2 metal oxide, the mole ratio of the Group 4 metal oxide to the Group
2
metal oxide may be in the range of from 1000:1 to 1:2, such as from 500:1 to
2:3,
preferably from 100:1 to 1:1 and more preferably from 50:1 to 2:1, based on
the
total moles of the Group 4 and Group 2 metal oxides. In addition, the catalyst
composition can contain from 1 to 25 %, preferably from 1 to20 % and more
preferably from 1 to 15 %, by weight of Group 2 metal based on the total
weight
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of the mixed metal oxide, particularly where the Group 2 metal oxide is
calcium
oxide and the Group 4 metal oxide is a zirconium metal oxide.
Catalyst Composition
[0048] 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 40Q weight percent.
[0049] 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.
[0050] Aluminum chlorhydrol, a hydroxylated aluminum based sol
containing a chloride counter ion, has the general formula of
AlmO"(OH)oClp~x(HZO) 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)24C1~~12(HZO) 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
or more other alumina materials such as aluminum oxyhydroxide, y-alumina,
boehmite, diaspore, and transitional aluminas such as a-alumina, (3-alumina, y-
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alumina, 8-alumina, s-alumina, x-alumina, and p-alumina, aluminum
trihydroxide,
such as gibbsite, bayerite, nordstrandite, doyelite, and mixtures thereof.
[0051] Non-limiting examples of commercially available colloidal alumina
sots include Nalco 8676 available from Nalco Chemical Co., Naperville,
Illinois,
and Nyacol AL20DW available from Nyacol Nano Technologies, Inc., Ashland,
Massachussetts.
[0052] 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.
[0053] 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.
[0054] 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 ~,m to 0.6 p,m with a D9o particle size
distribution of
less than 1 p,m.
[0055] Where the catalyst composition contains a binder or matrix material,
the catalyst composition typically contains from 1 % to 80%, preferably from
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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.
(0056] 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.
(0057] 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
0[ 058] 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 oxides) is
unnecessary and, in general, is not preferred.
0059 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
shaped and sized particles by well-known techniques such as spray drying,
pelletizing, extrusion, and the like.
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[0060] 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.
[0061] 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.
[0062] 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.
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LTse of Catalyst Composition
[0063] The catalyst composition described above is useful in a variety of
processes including cracking, of for example a naphtha feed to light olefins)
(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;
polymerization, of for example one or more olefins) to produce a polymer
product; reforming; hydrogenation; dehydrogenation; dewaxing, of for example
hydrocarbons to remove straight chain paraffms; 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.
[0064] Preferred processes include processes for converting naphtha to
highly aromatic mixtures; converting light olefm(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.
[0065] 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 SO 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.
[0066] 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
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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.
[0067] 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 olefins) 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.
[0068] 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
olefins) 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 20 weight percent, such as greater than 30
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.
[0069] Using the catalyst composition of the invention for the conversion of
a feedstock comprising methanol and dimethylether to ethylene and propylene,
it
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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).
[0070] 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.
[0071] 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°G to
650°C, preferably from 350°C to 600°C and more preferably
from 350°C to
550°C.
[0072] 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.
[0073] 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 hr'', preferably
from 2
hr'' to 3000 hr'', more preferably from 5 hr'' to 1500 hr'', 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''.
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[0074] 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.
[0075] 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 reactors) in the reactor system. The feedstock is converted in the riser
reactors) 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.
[0076] 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.
[0077] 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).
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[0078] The gaseous effluent is withdrawn from the disengaging system and
is passed through a recovery system for separating and purifying the light
olefm(s), particularly ethylene and propylene, in the gaseous effluent.
[0079] In one practical embodiment, the process of the invention forms part
of an integrated process for producing light olefins) 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, which is herein fully incorporated by reference.
[0080] In another more fully integrated process, optionally combined with
the integrated processes described above, the olefins) produced are directed
to
one or more polymerization processes for producing various polyolefins.
[0081] In order to provide a better understanding of the present invention
including representative advantages thereof, the following Examples are
offered.
[0082] In the Examples, LEI is defined as the ratio of the lifetime of a
molecular sieve catalyst composition containing an active metal oxides)
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
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based on the rate of decrease in conversion over the last two data points in
the
experiment.
[0083] "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
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 CS+'s axe average
selectivities weighted over the run. Note that the CS+'s consist only of CS'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
0084 A silicoaluminophosphate molecular sieve, SAPO-34, designated as
MSA, was crystallized in the presence of tetraethyl ammonium hydroxide (Rl)
and dipropylamine (R2) as the organic structure directing agents ox templating
agents. A mixture of the following mole ratio composition:
0.2SiOz/A12O3/PZOS/0.9R1/1.5R2/SOHzO.
was prepaxed 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
(~5%). These additions were made with stirring to form a homogeneous mixture.
To this homogeneous mixture Ludox AS40 (40% of Si02) 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.
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Example B
Conversion Process
[0085] All conversion data presented were obtained using a microflow
reactor consisting of a stainless steel reactor (I/4 inch (0.64 cm) outer
diameter)
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-1. 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
[0086] One thousand grams of ZrOCIz~8Hz0 was dissolved with stirring in
3.0 liters of distilled water. Another solution containing 400 grams of
concentrated NH~OH and 3.0 liters of distilled water was prepared. Both
solutions
were heated to 60°C. These two heated solutions were combined at a rate
of
SOmI/min using nozzle mixing. 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 product was
calcined to
700°C in flowing air for 3 hours to produce an active zirconium oxide
material.
Example 2
[0087] Five hundred grams of ZrOCIz~8H20 and 84 grams of La(N03)3~6H20
were dissolved with stirring in 3.0 liters of distilled water. Another
solution
containing 260 grams of concentrated NH4OH and 3.0 liters of distilled water
was
prepared. Both solutions were heated to 60°C and then combined at the
rate of SO
ml/min using nozzle mixing to form the final mixture, a slurry. The pH of the
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final mixture was adjusted to approximately 9 by the addition of concentrated
ammonium hydroxide. This slurry was then put in a polypropylene bottle and
placed in a steam box (100°C) for 72 hours. The resulting product
formed was
recovered by filtration, washed with excess water, and dried overnight at
85°C. A
portion of this product, was calcined to 700°C in flowing air for 3
hours to
produce an active mixed metal oxide containing a nominal 10 weight percent La
(lanthanum) based on the final weight of the mixed metal oxide.
Example 3
[0088] Fifty grams of ZrOC12~8H20 were dissolved with stirring in 300m1 of
distilled water. Another solution containing 4.2 grams of La(N03)3~6H20 and
300
ml of distill water was prepared. These two solutions were combined with
stirring
to form a final mixture. The pH of the final mixture, a slurry, was adjusted
to
approximately 9 by the addition of concentrated ammonium hydroxide (28.9
grams). This slurry was then put in a polypropylene bottle and placed in a
steam
box (100°C) fox 72 hours. The resulting product formed was recovered by
filtration, washed with excess water, and dried overnight at 85°C. A
portion of
this resulting product was calcined to 700°C in flowing air for 3 hours
to produce
an active mixed metal oxide containing a nominal 5 weight percent La based on
the final weight of the mixed metal oxide.
Example 4
[0089] Five hundred grams of ZrOC12~8H20 and 70 grams of Y(N03)3~5H20
were dissolved with stirring in 3.0 liters of distilled water. Another
solution
containing 260 grams of concentrated NH40H and 3.0 liters of distilled water
was
prepared. Both solutions were heated to 60°C and then combined at the
rate of 50
ml/min using nozzle mixing to form a final mixture. The pH of the final
mixture,
a slurry, was adjusted to approximately 9 by the addition of concentrated
ammonium hydroxide. This slurry was then put in a polypropylene bottle and
placed in a steam box (100°C) for 72 hours. The resulting product
formed was
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recovered by filtration, washed with excess water, and dried overnight at
85°C. A
portion of the resulting product was calcined to 700°C in flowing air
for 3 hours to
produce an active mixed metal oxide containing a nominal 10 weight percent Y
(yttrium) based on the final weight of the mixed metal oxide.
Example 5
[0090] Five hundred grams of ZrOC12~8Hz0 and 56 grams of
Ca(N03)2~4Hz0 were dissolved with stirring in 3000m1 of distilled water.
Another
solution containing 260 grams of NH~OH and 3000m1 of distilled water was
prepared. These two solutions were combined with stirxing. The pH of the final
composite was adjusted to approximately 9 by the addition of concentrated
ammonium hydroxide (160 grams). This slurry was then put in polypropylene
bottles and placed in a steambox (100°C) for 72 hours. The resulting
product
fornzed was recovered by filtration, washed with excess water, and dried
overnight
at 85°C. A portion of this product was calcined to 700°C in
flowing air for 3
hours to produce an active mixed metal oxide containing a nominal 5 weight
percent Ca (calcium) based on the final weight of the mixed metal oxide.
Example 6
[0091] Seventy grams of TiOS04~xH~S04~xH20 (x=1) were dissolved with
stirring in 400 ml of distilled water. Another solution containing 12.8 grams
of
CeS04 and 300 ml of distilled water was prepared. These two solutions were
combined with stirring. The pH of the final composite was adjusted to
approximately 8 by the addition of concentrated ammonium hydroxide (64.3
grams). 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 product
was calcined to 700°C in flowing air for 3 hours to produce an active
mixed metal
oxide containing a nominal 5 weight percent Ce based on the final weight of
the
mixed metal oxide.
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Example 7
[0092] Five grams of HfOCI2~xHZ0 was dissolved with stirring in 100m1 of
distilled water. The pH of the final composite was adjusted to approximately 9
by
the addition of concentrated ammonium hydroxide (4.5 grams). This slurry was
then put in a polypropylene bottle and placed in a steambox (100°C) for
72 hours.
The product fornzed 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 an active hafnium oxide.
Example 8
[0093] Five grams of HfOCI2~xH20 and 0.62 grams of La(N03)3~6Hz0 were
dissolved with stirring in 100m1 of distilled water. The pH of the final
composite
was adjusted to approximately 9 by the addition of concentrated ammonium
hydroxide (3.5 grams). This slurry was then put in a polypropylene bottle 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 an active
mixed metal oxide containing a nominal 5 weight % La based on the final weight
of the mixed metal oxide.
Example 9
[0094] The carbon dioxide uptake of the oxides of Examples 1 through 8
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 fox 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
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carbon dioxide uptake in terms of mg carbon dioxide/m2 of the metal oxide
presented in Table 1.
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Table 1
Example Catalyst Dry mg of COZ Surface COz Uptake
Weight (mg) Area (mg of
(m2/g) COz/m2)
1 76 0.0980 29 0.045
2 115 0.7781 80 0.085
3 73 0.4243 89 0.065
4 97 0.3808 100 0.039
78 0.5399 85 0.081
6 43 0.1035 50 0.048
7 158 0.3704 25 0.094
8 164 0.7359 60 0.075
Example 10 (Comparative)
[0095] The performance of the control, the molecular sieve of Example A,
MSA, using a 50 mg load in the reactor and Lender the conditions discussed
above
in Example B is reported in Tables 2 and 3.
Example 11
[0096] In this Example, the catalyst composition consisted of 40 mg MSA
of Example A and 10 mg of the active zirconium oxide of Example 1. The
catalyst composition and active mixed metal oxide were well mixed, and then
diluted with quartz to form the reactor bed. The results of testing this
catalyst
composition in the process of Example B are shown in Tables 2 and 3. The
results
indicate that the addition of the active zirconium oxide to the catalyst bed
increased the lifetime of the molecular sieve composition significantly, and
decreased the amounts of undesired ethane and propane.
Example 12
[0097] In this Example, the catalyst composition consisted of 40 mg MSA
of Example A and 10 mg of the active mixed metal oxide containing 10 weight
percent La, described in Example 2. The catalyst composition and active mixed
metal oxide were well mixed, and then diluted with quartz to form the reactor
bed.
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The results of testing this catalyst composition in the process of Example B
are
shown in Tables 2 and 3. The data in Tables 2 and 3 illustrate that by
constituting
20% of the catalyst composition load with the active mixed metal oxide
containing 10 weight percent La, the lifetime of the molecular sieve doubled,
as
indicated by its LEI value of 2. In addition, there was a net gain of 1.7% in
prime
olefins on an absolute basis, with most of this gain being due to an increase
in
propylene of 2.76%, offsetting a small decrease in ethylene of 1.07%.
Selectivity
to ethane decreased by 39% and selectivity to propane decreased by 37%
suggesting that hydrogen transfer reactions have been significantly reduced.
Example 13
[0098] In this Example, the catalyst consisted of 30 mg MSA of Example A
and 20 mg of the active mixed metal oxide containing 10 weight percent La, as
described in Example 2. The catalyst composition and active mixed metal oxide
were well mixed, and then diluted with quartz to form the reactor bed. The
results
of testing this catalyst composition in the process of Example B are shown in
Tables 2 and 3. The data of Tables 2 and 3 illustrate that by constituting 40%
of
the catalyst composition load containing 10 weight percent La, the lifetime of
the
SAPO-34 catalyst composition increased by 440%. Trends in selectivity for this
catalyst loading are similar to those seen in Example 8.
Example 14
[0099] In this Example, the catalyst composition consisted of 40 mg MSA
from Example A and 10 mg of the active mixed metal oxide containing 10 weight
percent Y, as described in Example 4. The catalyst composition and active
mixed
metal oxide were well mixed, and then diluted with quartz to form the reactor
bed.
The results of testing this catalyst composition in the process of Example B
are
shown in Tables 2 and 3. The substitution of yttrium for lanthanum has the
effect
of increasing the LEI even further. However, the improvements in selectivity
are
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not as dramatic as seen with the lanthanum, with the gain in prime olefin
being
1.2% on an absolute basis.
Example 15
[0100] In this Example, the catalyst consisted of 40 mg MSA of Example A
and 10 mg of the active mixed metal oxide containing 5 weight percent La, as
described in Example 3. The catalyst composition and active mixed metal oxide
were well mixed, and then diluted with quartz to form the reactor bed. The
results
of testing this catalyst composition in the process of Example B are shown in
Tables 2 and 3. It will be seen that the active mixed metal oxide containing 5
weight percent lanthanum oxide seems to have a much stronger effect in
increasing the LEI than the active mixed metal oxide of Example 8 containing
10
weight percent La.
Example 16
[0101] In this Example 16, the catalyst consisted of 40 mg MSA of Example
A and 10 mg of an active mixed metal oxide containing 5 weight percent Ca, as
described in Example 5. The catalyst composition and active mixed metal oxide
were well mixed, and then diluted with quartz to form the reactor bed. The
results
of this experiment in the reactor and conditions discussed above in Example B
are
shown in Tables 2 and 3. The active mixed metal oxide containing 5 weight
percent calcium oxide has increased the lifetime of the molecular sieve
composition by 223%.
Example 17 (Comparative)
[0102] In this Comparative Example, the catalyst composition consisted of 40
mg MSA of Example A and 10 mg of an amorphous silicalalumina, an inactive
mixed metal oxide. The molecular sieve catalyst composition and the inactive
mixed metal oxide catalysts were well mixed, and then diluted with quartz to
form
the reactor bed. The results of testing this catalyst composition in the
process of
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Example B are also shown in Tables 2 and 3. This Comparative Example 17
illustrates a reduction in LEI to a value less than 1.0 when an inactive mixed
metal
oxide is utilized as compared to Example 11 of the invention. In addition,
there is
a loss of 1.07% in prime olefin selectivity, and no significant reduction in
ethane
and propane production.
Example 18
[0103] In this Example, the catalyst composition consisted of 40 mg MSA
from Example A and 10 mg an active mixed metal oxide containing Ce and
titania, as described in Example 6. The catalyst composition and active mixed
metal oxide were well mixed, and then diluted with quartz to form the reactor
bed.
The results of testing this catalyst composition in the process of Example B
are
shown in Tables 2 and 3. The presence of the active mixed metal oxide
increased
the lifetime of the molecular sieve composition by 134%
Example 19
[0104] In this Example, the catalyst composition.consisted of 40 mg MSA of
Example A and 10 mg of the active hafnium metal oxide described in Example 7.
The catalyst composition and active metal oxide were well mixed, and then
diluted with quartz to form the reactor bed. The results of testing this
catalyst
composition in the process of Example B are shown in Tables 2 and 3. The data
in Tables 2 and 3 illustrate that by constituting 20% of the catalyst
composition
load with the active hafnium metal oxide, the lifetime of the molecular sieve
has
increased by 126%. Selectivity to ethane decreased by 40% and selectivity to
propane decreased by 46% suggesting that hydrogen transfer reactions have been
significantly reduced.
Example 20
[0105] In this Example, the catalyst composition consisted of 40 mg MSA of
Example A and 10 mg of the active mixed metal oxide containing 5 weight ,
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percent La, described in Example 8. The catalyst composition and active mixed
metal oxide were well mixed, and then diluted with quartz to form the reactor
bed.
The results of testing this catalyst composition in the process of Example B
are
shown in Tables 2 and 3. The data in Tables 2 and 3 illustrate that by
constituting
20% of the catalyst composition load with the active mixed metal oxide
containing 5 weight percent La, the lifetime of the molecular sieve has
increased
by 150%. Selectivity to ethane decreased by 51% and selectivity to propane
decreased by 51 % suggesting that hydrogen transfer reactions have been
significantly reduced.
Table 2
Example Reactor Bed LEI Prime C _~C C Purity
= ~
2 3
Composition (wt%) Olefin (
(%) )
(Comp)100% MSA 1 74.65 0.92 92.7
11 80% MSA/20%Zr02 2.64 74.79 0.82 96.1
12 80% MSA / 20% 2.03 76.34 0.84 95.6
of
10% LalZrQz
13 60% MSA / 40% 5.41 75.50 0.85 94.6
of
10% La/Zr02
14 80% MSA / 20% 2.79 75.81 0.85 94.9
of
10% Y/Zr02
80% MSA / 20% 4.85 75.84 0.84 94.8
of
5% LalZr02
16 80% MSA / 20% 3.23 73.85 0.79 96.7
of
5% Ca/ZrOz
17 (Comp)80% MSA / 20% 0.79 73.58 0.93 93.3
of
51~2/A1~03
18 80% MSA / 20% 2.34 65.65 0.87 95.1
of
Ce/TiO~
19 80% MSA / 20% 2.26.72.98 0.71 96.2
of
Hf02
80% MSA / 20% 2.50 72.75 0.76 96.5
of
5% La/HfOz
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Table 3
Product
Selectivities
(%)
Example Reactor Cg4 Cz CZ C3 C3 C's CS+
Bed (wt
%)
100% MSA 1.51 35.820.95 38.83 3.05 14.50 2.12
(Comp)
11 80% MSA 1.50 33.740.53 41.05 1.68 14.79 3.31
/
20% Zr02
12 80% MSA 1.31 34.750.58 41.59 1.93 14.96 2.46
/
20% of
10%
LalZrOz
13 60% MSA 1.47 34.750.66 40.75 2.32 14.76 2.52
/
40% of
10%
LaJZr02
14 80% MSA/ 1.32 34.920.66 40.88 2.20 14.41 3.07
20% of
10%
Y/ZrOz
80% MSA 1.26 34.590.64 41.25 2.28 14.96 2.52
/
20% of
5%
La/Zr02
16 80% MSA 1.50 32.650.42 41.20 1.43 14.84 5.34
/
20% of
5%
CalZr02
17 80% MSA 2.17 35.460.89 38.12 2.72 14.21 2.65
/
(Comp) 20% of
Si02/A1z03
18 80% MSA 6.79 30.570.75 35.09 1.80 12.72 3.97
/
20% of
Ce/TiOz
19 80% MSA 1.98 31.620.52 41.36 1.65 14.64 4.93
/
20% of
Hf~~
80% MSA 1.98 31.580.47 41.18 1.49 14.53 5.52
/
20% of
5%
La/Hf02
