U.S. patent application number 10/287251 was filed with the patent office on 2003-09-18 for catalytic cracking with zeolite itq-13.
Invention is credited to Buchanan, John Scott, Chen, Ten-Jen, Keusenkothen, Paul F., Schmitt, Kirk D..
Application Number | 20030173254 10/287251 |
Document ID | / |
Family ID | 28044699 |
Filed Date | 2003-09-18 |
United States Patent
Application |
20030173254 |
Kind Code |
A1 |
Chen, Ten-Jen ; et
al. |
September 18, 2003 |
Catalytic cracking with zeolite ITQ-13
Abstract
A catalytic cracking process is disclosed for feedstock
containing hydrocarbons having at least 5 carbon atoms. The
feedstock is contacted, under catalytic cracking conditions, with a
9-member ring catalyst composition and, optionally, a large pore
molecular sieve, such as zeolite Y.
Inventors: |
Chen, Ten-Jen; (Kingwood,
TX) ; Keusenkothen, Paul F.; (Houston, TX) ;
Buchanan, John Scott; (Lambertville, NJ) ; Schmitt,
Kirk D.; (Pennington, NJ) |
Correspondence
Address: |
EXXONMOBIL CHEMICAL COMPANY
P O BOX 2149
BAYTOWN
TX
77522-2149
US
|
Family ID: |
28044699 |
Appl. No.: |
10/287251 |
Filed: |
November 4, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60363100 |
Mar 12, 2002 |
|
|
|
Current U.S.
Class: |
208/120.01 ;
208/118; 208/119 |
Current CPC
Class: |
C10G 11/05 20130101;
B01J 29/70 20130101; G09F 11/00 20130101; B01J 29/86 20130101; C10G
2400/20 20130101; G09F 19/00 20130101 |
Class at
Publication: |
208/120.01 ;
208/118; 208/119 |
International
Class: |
C10G 011/05 |
Claims
We claim:
1. A catalytic cracking process comprising contacting, under
catalytic cracking conditions, a feedstock comprising hydrocarbons
having at least 5 carbon atoms with a catalyst composition
comprising a synthetic porous crystalline material having a
multi-dimensional channel system, at least a first parallel set of
said channels comprising 9-member rings having a pore size of at
least about 3.6 Angstroms.
2. The process of claim 1, wherein at least a second set of said
channels comprises 10-member rings.
3. The process of claim 1, wherein the catalyst channel system is
3-dimensional.
4. The process of claim 1, wherein said at least first parallel set
of channels has a pore size of at least about 4.0 Angstroms.
5. The process of claim 1, wherein said at least first parallel set
of channels has a pore size of at least about 4.2 Angstroms.
6. The process of claim 4, wherein said at least first parallel set
of channels has a pore size less than or equal to about 5.0
Angstroms.
7. The process of claim 5, wherein said at least first parallel set
of channels has a pore size less than or equal to about 5.0
Angstroms.
8. The process of claim 1, wherein the catalyst is
metal-stabilized.
9. The process of claim 8, wherein the catalyst is metal-stabilized
with at least one of at least one metal of Group 2a, 3b, 4b, 7b, 8,
1b, 2b, 3a and 5a of The Periodic Table of the Elements.
10. The process of claim 9, wherein the catalyst is
metal-stabilized with at least one of copper, phosphorus, iron,
silver, magnesium, lanthanum, zinc, aluminum, zirconium, manganese,
and cerium.
11. The process of claim 10, wherein the catalyst is metal
stabilized with at least one of copper and phosphorous.
12. The process of claim 1, wherein the feedstock is naphtha.
13. The process of claim 1, wherein the feedstock is at least one
of gas oil, vacuum gas oil and residual oil vacuum resid.
14. The process of claim 1, which is a fluid catalytic cracking
process.
15. The process of claim 1, wherein the catalyst composition is
used as an additive catalyst.
16. The process of claim 1, wherein the catalyst composition is
used as a base catalyst.
17. The process of claim 1, wherein the catalyst composition
comprises a molecular sieve.
18. The process of claim 17, wherein the catalyst comprises at
least one of zeolite Y, zeolite REY, zeolite X, zeolite USY and
zeolite REUSY.
19. The process of claim 1, wherein propylene is produced.
20. The process of claim 19, wherein the propylene selectivity is
at least about 30%.
21. The process of claim 20, wherein the propylene selectivity is
at least about 50%.
22. The process of claim 21, wherein the propylene selectivity is
at least about 60%.
23. The process of claim 19, wherein light olefins are produced and
the light olefin selectivity is at least about 50%.
24. The process of claim 23, wherein the light olefin selectivity
is at least about 70%.
25. The process of claim 24, wherein the light olefin selectivity
is at least about 80%.
26. The process of claim 20, wherein light olefins are produced and
the light olefin selectivity is at least about 50%.
27. The process of claim 21, wherein light olefins are produced and
the light olefin selectivity is at least about 70%.
28. The process of claim 23, wherein light olefins are produced and
the light olefin selectivity is at least about 80%.
29. The process of claim 1, wherein the catalyst composition
comprises a synthetic porous crystalline material comprising a
framework of tetrahedral atoms bridged by oxygen atoms, the
tetrahedral atom framework being defined by a unit cell with atomic
coordinates in nanometers shown in Table 1, wherein each coordinate
position may vary within .+-.0.05 nanometer.
30. The process of claim 1, wherein the synthetic porous
crystalline material has an X-ray diffraction pattern including
d-spacing and relative intensity values substantially as set forth
in Table 2.
31. The process of claim 29, wherein the synthetic porous
crystalline material has an X-ray diffraction pattern including
d-spacing and relative intensity values substantially as set forth
in Table 2.
32. The process of claim 1, wherein the synthetic porous
crystalline material has a composition comprising the molar
relationship X.sub.2O.sub.3:(n)YO.sub.2, wherein n is at least
about 5, X is a trivalent element, and Y is a tetravalent
element.
33. The process of claim 29, wherein the synthetic porous
crystalline material has a composition comprising the molar
relationship X.sub.2O.sub.3:(n)YO.sub.2, wherein n is at least
about 5, X is a trivalent element, and Y is a tetravalent
element.
34. The process of claim 30, wherein the synthetic porous
crystalline material has a composition comprising the molar
relationship X.sub.2O.sub.3:(n)YO.sub.2, wherein n is at least
about 5, X is a trivalent element, and Y is a tetravalent
element.
35. The process of claim 31, wherein the synthetic porous
crystalline material has a composition comprising the molar
relationship X.sub.2O.sub.3:(n)YO.sub.2, wherein n is at least
about 5, X is a trivalent element, and Y is a tetravalent
element.
36. The process recited in claim 35, wherein X is a trivalent
element selected from the group consisting of boron, iron, indium,
gallium, aluminum, and a combination thereof; and Y is a
tetravalent element selected from the group consisting of silicon,
tin, titanium, germanium, and a combination thereof.
37. The process recited in claim 36, wherein X comprises boron or
aluminum and Y comprises silicon.
38. The process of claim 37, wherein X is aluminum.
39. The process of claim 1, wherein the catalyst composition also
comprises a large pore molecular sieve having a pore size greater
than 6 Angstrom.
40. The process of claim 39, wherein the large pore molecular sieve
has a pore size greater than 7 Angstrom.
41. The process of claim 39, wherein the weight ratio of said
synthetic porous crystalline material to the large pore molecular
sieve is about 0.005 to about 50.
42. The process of claim 40, wherein the weight ratio of said
synthetic porous crystalline material to the large pore molecular
sieve is about 0.005 to about 50.
43. The process of claim 41, wherein the weight ratio of said
synthetic porous crystalline material to the large pore molecular
sieve is about 0.1 to about 1.0.
44. The process of claim 42, wherein the weight ratio of said
synthetic porous crystalline material to the large pore molecular
sieve is about 0.1 to about 1.0.
45. The process of claim 11, wherein the catalyst is
metal-stabilized with copper.
46. The process of claim 1, wherein the catalyst composition
comprises at least one of a zeolite and SAPO.
47. The process of claim 1, wherein at least part of the reaction
zone is at a temperature of about 500.degree.-600.degree. C.
48. The process of claim 1, wherein the process total pressure is
about 0.5 to about 10 atmospheres.
49. The process of claim 48, wherein the process total pressure is
about 1 to about 3 atmospheres.
Description
CROSS-REFERENCE TO RELATED APPLICATION(S)
[0001] The present application is related to (1) application Ser.
No. (awaited) filed on Oct. 29, 2002, entitled "Aromatics
Conversion with ITQ-13" by inventors John S. Buchanan et al.
(attorney docket number 2002B145); (2) application Ser. No.
09/866,907 filed on May 29, 2001, entitled "Synthetic Porous
Crystalline Material ITQ-13, Its Synthesis and Use" by inventors
Girones et al. (attorney docket number P2001J030); and (3)
provisional application Ser. No. 60/363,100 filed on Mar. 5, 2002
entitled "Catalytic Cracking with Zeolite ITQ-13" by inventor Corma
(attorney docket number P2002J026). All of these applications are
incorporated herein by reference.
BACKGROUND TO THE INVENTION
[0002] This invention relates to a process for catalytic cracking
of hydrocarbon feedstocks to produce an enhanced yield of light
(C.sub.2-C.sub.4) olefins and in particular an enhanced yield of
propylene.
DESCRIPTION OF THE PRIOR ART
[0003] Catalytic cracking, and particularly fluid catalytic
cracking (FCC), is routinely used to convert heavy hydrocarbon
feedstocks to lighter products, such as gasoline and distillate
range fractions. Conventional processes for catalytic cracking of
heavy hydrocarbon feedstocks to gasoline and distillate fractions
typically use a large pore molecular sieve, such as zeolite Y, as
the primary cracking component. It is also well known to add a
medium pore molecular sieve, such as ZSM-5 and ZSM-35, to the
cracking catalyst composition to increase the octane number of the
gasoline fraction (see U.S. Pat. No. 4,828,679).
[0004] In addition, it is known from, for example, U.S. Pat. No.
4,969,987 to employ medium pore molecular sieves, such as ZSM-5 and
ZSM-12, to crack paraffinic and naphthenic naphthas to produce a
light olefinic fraction rich in C.sub.4-C.sub.5 isoalkenes and a
C.sub.6+ liquid fraction of enhanced octane value.
[0005] There is, however, an increasing need to enhance the yield
of light olefins, especially propylene, in the product slate from
catalytic cracking processes. Thus propylene is in high demand for
a variety of commercial applications, particularly in the
manufacture of polypropylene, isopropyl alcohol, propylene oxide,
cumene, synthetic glycerol, isoprene, and oxo alcohols.
[0006] Co-pending U.S. patent application Ser. No. 09/866,907,
filed May 29, 2001, describes a synthetic porous crystalline
material, ITQ-13, which is a single crystalline phase material
having a unique 3-dimensional channel system comprising three sets
of channels, two defined by 10-membered rings of tetrahedrally
coordinated atoms and the third by 9-membered rings of
tetrahedrally coordinated atoms. Co-pending U.S. patent application
Ser. No. 60/362,100, filed Mar. 5, 2002, describes a process for
cracking hydrocarbons using a catalyst comprising ITQ-13.
SUMMARY OF THE INVENTION
[0007] According to one aspect of the present invention a catalytic
cracking process comprises contacting, under catalytic cracking
conditions, a feedstock comprising hydrocarbons having at least 5
carbon atoms with a catalyst composition comprising a synthetic
porous crystalline material having a multi-dimensional channel
system, at least a first parallel set of said channels comprising
9-member rings having a pore size of at least about 3.6 Angstroms.
According to another aspect, a second set of channels comprises
10-member rings. Preferably, the catalyst channel system is
3-dimensional. A preferred hydrocarbon feed is naphtha or at least
one of gas oil, vacuum gas oil and residual oil vacuum resid. Also
preferably, the catalytic cracking process is a fluid catalytic
cracking process.
[0008] According to a further aspect of the present invention, the
at least first parallel set of channels has a pore size of at least
about 4.0 Angstroms, more preferably at least about 4.2 Angstroms.
In another aspect, the at least first parallel set of channels has
a pore size less than or equal to about 5.0 Angstroms.
[0009] According to yet a further aspect of the invention, the
catalyst can be metal-stabilized. Preferably, the catalyst is
metal-stabilized with at least one of at least one metal of Group
2a, 3b, 4b, 7b, 8, 1b, 2b, 3a and 5a of The Periodic Table of the
Elements. More preferably, the catalyst is metal-stabilized with at
least one of copper, phosphorus, iron, silver, magnesium,
lanthanum, zinc, aluminum, zirconium, manganese, and cerium. Even
more preferably, the catalyst is metal-stabilized with at least one
of copper and phosphorus. Most preferably, copper is used.
[0010] In one aspect of the present invention the catalyst
composition is used as an additive catalyst. In another aspect, the
catalyst composition is used as a base catalyst. In yet another
aspect in accordance with the present invention, the catalyst
composition comprises a molecular sieve. According to another
aspect, the molecular sieve comprises at least one of zeolite Y,
zeolite REY, zeolite X, zeolite USY and zeolite REUSY.
[0011] According to another aspect of the present invention,
propylene is produced. Preferably, the propylene selectivity (moles
of propylene per mole of C.sub.4.sup.- produced) is at least about
30%, more preferably at least about 50 %, most preferably at least
about 60%. As used herein, propylene selectivity is defined as the
ratio of propylene to total C.sub.1-C.sub.4 hydrocarbon products
(weight basis).
[0012] According to yet another aspect of the present invention,
light olefins (C.sub.3+C.sub.4) are produced and the light olefin
selectivity is at least about 50%, preferably about 70%, more
preferably about 80%. As used herein, light olefin selectivity is
defined as the ratio of propylene and butylene to total
C.sub.1-C.sub.4 hydrocarbon products (weight basis).
[0013] According to another aspect of the present invention, the
catalyst composition comprises a synthetic porous crystalline
material comprising a framework of tetrahedral atoms bridged by
oxygen atoms, the tetrahedral atom framework being defined by a
unit cell with atomic coordinates in nanometers shown in Table 1,
wherein each coordinate position may vary within .+-.0.05
nanometer.
[0014] Preferably, the synthetic porous crystalline material has an
X-ray diffraction pattern including d-spacing and relative
intensity values substantially as set forth in Table 2 below.
[0015] In a further aspect of the invention, the catalyst
composition also comprises a large pore molecular sieve having a
pore size greater than 6 Angstroms, preferably greater than 7
Angstroms.
DESCRIPTION OF DRAWINGS
[0016] FIG. 1 is a non-limiting, schematic illustration of a unit
cell of ITQ-13, a 9-member ring synthetic porous crystalline
material in accordance with the present invention, showing the
positions of the tetrahedral atoms.
[0017] FIG. 2 is a non-limiting schematic illustration of the
9-member ring channel system of ITQ-13, again showing the positions
of the tetrahedral atoms.
[0018] FIGS. 3 and 4 are non-limiting, schematic illustrations,
similar to FIG. 2, of the ten-ring channel systems of ITQ-13.
[0019] FIGS. 5-7 are X-ray powder diffraction patterns of the
9-member ring product of Example 6, as synthesized, after
calcination and after insertion of aluminum, respectively.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0020] The particulars shown herein are by way of example and for
purposes of illustrative discussion of the embodiments of the
present invention only and are presented to provide what is
believed to be the most useful and readily understood description
of the principles and conceptual aspects of the present invention.
In this regard, no attempt is made to show details of the present
invention in more detail than is necessary for the fundamental
understanding of the present invention, the description making
apparent to those skilled in the art how the several forms of the
present invention may be embodied in practice.
[0021] Unless otherwise stated, all percentages, parts, ratios,
etc., are by weight. Unless otherwise stated, a reference to a
compound or component includes the compound or component by itself,
as well as in combination with other compounds or components, such
as mixtures of compounds.
[0022] Further, when an amount, concentration, or other value or
parameters is given as a list of upper preferable values and lower
preferable values, this is to be understood as specifically
disclosing all ranges formed from any pair of an upper preferred
value and a lower preferred value, regardless whether ranges are
separately disclosed.
[0023] The present invention provides a process for converting
feedstock hydrocarbon compounds to product hydrocarbon compounds of
lower molecular weight than the feedstock hydrocarbon compounds. In
particular, the present invention provides a process for
catalytically cracking a hydrocarbon feedstock having at least 5
carbon atoms to selectively produce C.sub.2 to C.sub.4 olefins, and
in particular to selectively produce propylene. The process of the
invention employs a catalyst composition comprising a synthetic
porous crystalline material having a multi-dimensional channel
system, at least a first parallel set of said channels comprising
9-member rings having a pore size of at least about 3.6 Angstroms.
Preferably, the pore size of the 9-member rings is at least about
4.0 Angstroms. More preferably, the pore size of the 9-member rings
is at least about 4.2 Angstroms. Also preferably, these rings have
a pore size less than or equal to about 5.0 Angstroms. Preferably,
the catalyst composition comprises a synthetic porous crystalline
material having a multi-dimensional channel system, at least a
first parallel set of said channels comprising 9-member rings
having a pore size greater than about 3.6 Angstroms and at least a
second set of channels comprising at least 10-member rings. The
catalyst composition preferably comprises at least one of a zeolite
or SAPO.
[0024] It should be understood throughout this specification that a
reference to a single dimension of a pore describes its smallest
dimension. Techniques for determining how many members there are in
a ring (e.g., 9 members), as well as pore size are well known in
the art. By way of non-limiting example, Atlas of Zeolite Framework
Types, 5.sup.th edition (2001), Ch. Baelocher, W. M. Meier, and D.
H. Olson, which is incorporated herein by reference, describes such
techniques.
[0025] According to a preferred aspect of the present invention,
the catalyst comprises ITQ-13, which is a synthetic porous
crystalline material comprising a framework of tetrahedral atoms
bridged by oxygen atoms, the tetrahedral atom framework being
defined by a unit cell with atomic coordinates in nanometers shown
in Table 1, wherein each coordinate position may vary within
.+-.0.05 nanometer. According to another aspect in accordance with
the present invention, the catalyst composition comprises synthetic
porous crystalline material ITQ-13 and, optionally, a large pore
molecular sieve having a pore size greater than 6 Angstroms. In yet
a further aspect in accordance with the present invention, the
large pore molecular sieve has a pore size greater than 7
Angstroms.
[0026] The synthetic porous crystalline material ITQ-13 is
described in our co-pending U.S. patent application Ser. No.
09/866,907, incorporated herein by reference, and is a single
crystalline phase that has a unique 3-dimensional channel system
comprising three sets of channels. In particular, ITQ-13 comprises
a first set of generally parallel channels each of which is defined
by a 10-membered ring of tetrahedrally coordinated atoms, a second
set of generally parallel channels which are also defined by
10-membered rings of tetrahedrally coordinated atoms and which are
perpendicular to and intersect with the channels of the first set,
and a third set of generally parallel channels which intersect with
the channels of said first and second sets and each of which is
defined by a 9-membered ring of tetrahedrally coordinated atoms.
The first set of 10-ring channels each has cross-sectional
dimensions of about 4.8 Angstrom by about 5.5 Angstrom, whereas the
second set of 10-ring channels each has cross-sectional dimensions
of about 5.0 Angstrom by about 5.7 Angstrom. The third set of
9-ring channels each has cross-sectional dimensions of about 4.0
Angstrom by about 4.9 Angstrom.
[0027] The structure of ITQ-13 may be defined by its unit cell,
which is the smallest structural unit containing all the structural
elements of the material. Table 1 lists the positions of each
tetrahedral atom in the unit cell in nanometers; each tetrahedral
atom is bonded to an oxygen atom that is also bonded to an adjacent
tetrahedral atom. Since the tetrahedral atoms may move about due to
other crystal forces (presence of inorganic or organic species, for
example), a range of .+-.0.05 nm is implied for each coordinate
position.
1 TABLE 1 T1 0.626 0.159 0.794 T2 0.151 0.151 0.478 T3 0.385 0.287
0.333 T4 0.626 0.158 0.487 T5 0.153 0.149 0.781 T6 0.383 0.250
1.993 T7 0.473 0.153 0.071 T8 0.469 0.000 1.509 T9 0.466 0.000
1.820 T10 0.626 0.979 0.794 T11 1.100 0.987 0.478 T12 0.867 0.851
0.333 T13 0.626 0.980 0.487 T14 1.099 0.989 0.781 T15 0.869 0.888
1.993 T16 0.778 0.985 0.071 T17 0.783 0.000 1.509 T18 0.785 0.000
1.820 T19 0.151 0.987 0.478 T20 0.385 0.851 0.333 T21 0.153 0.989
0.781 T22 0.383 0.888 1.993 T23 0.473 0.985 0.071 T24 1.100 0.151
0.478 T25 0.867 0.287 0.333 T26 1.099 0.149 0.781 T27 0.869 0.250
1.993 T28 0.778 0.153 0.071 T29 0.626 0.728 1.895 T30 0.151 0.720
1.579 T31 0.385 0.856 1.433 T32 0.626 0.727 1.588 T33 0.153 0.718
1.882 T34 0.383 0.819 0.893 T35 0.473 0.722 1.171 T36 0.469 0.569
0.409 T37 0.466 0.569 0.719 T38 0.626 0.410 1.895 T39 1.100 0.418
1.579 T40 0.867 0.282 1.433 T41 0.626 0.411 1.588 T42 1.099 0.420
1.882 T43 0.869 0.319 0.893 T44 0.778 0.416 1.171 T45 0.783 0.569
0.409 T46 0.785 0.569 0.719 T47 0.151 0.418 1.579 T48 0.385 0.282
1.433 T49 0.153 0.420 1.882 T50 0.383 0.319 0.893 T51 0.473 0.416
1.171 T52 1.100 0.720 1.579 T53 0.867 0.856 1.433 T54 1.099 0.718
1.882 T55 0.869 0.819 0.893 T56 0.778 0.722 1.171
[0028] ITQ-13 can be prepared in essentially pure form with little
or no detectable impurity crystal phases and has an X-ray
diffraction pattern which is distinguished from the patterns of
other known as-synthesized or thermally treated crystalline
materials by the lines listed in Table 2 below.
2 d(.ANG.) Relative Intensities (I) 12.46 .+-. 0.2 .sup. w-vs 10.97
.+-. 0.2 .sup. m-vs 10.12 .+-. 0.2 vw-w 8.25 .+-. 0.2 vw 7.87 .+-.
0.2 .sup. w-vs 5.50 .+-. 0.15 w-m 5.45 .+-. 0.15 vw 5.32 .+-. 0.15
vw-w 4.70 .+-. 0.15 vw 4.22 .+-. 0.15 w-m 4.18 .+-. 0.15 vw-w 4.14
.+-. 0.15 w 3.97 .+-. 0.1 w 3.90 .+-. 0.1 w 3.86 .+-. 0.1 vw-m 3.73
.+-. 0.1 .sup. m-vs 3.66 .+-. 0.1 .sup. m-vs
[0029] These X-ray diffraction data were collected with a Scintag
diffraction system, equipped with a germanium solid state detector,
using copper K-alpha radiation. The diffraction data were recorded
by step-scanning at 0.02 degrees of two-theta, where theta is the
Bragg angle, and a counting time of 10 seconds for each step. The
interplanar spacings, d's, were calculated in Angstrom units, and
the relative intensities of the lines, I/I.sub.o is one-hundredth
of the intensity of the strongest line, above background, were
derived with the use of a profile fitting routine (or second
derivative algorithm). The intensities are uncorrected for Lorentz
and polarization effects. The relative intensities are given in
terms of the symbols vs=very strong (80-100), s=strong (60-80),
m=medium (40-60), w=weak (20-40), and vw=very weak (0-20). It
should be understood that diffraction data listed for this sample
as single lines may consist of multiple overlapping lines which
under certain conditions, such as differences in crystallographic
changes, may appear as resolved or partially resolved lines.
Typically, crystallographic changes can include minor changes in
unit cell parameters and/or a change in crystal symmetry, without a
change in the structure. These minor effects, including changes in
relative intensities, can also occur as a result of differences in
cation content, framework composition, nature and degree of pore
filling, crystal size and shape, preferred orientation and thermal
and/or hydrothermnal history.
[0030] ITQ-13 has a composition involving the molar
relationship:
X.sub.2O.sub.3:(n)YO.sub.2,
[0031] wherein X is a trivalent element, such as aluminum, boron,
iron, indium, and/or gallium, preferably boron; Y is a tetravalent
element such as silicon, tin, titanium and/or germanium, preferably
silicon; and n is at least about 5, such as about 5 to infinity,
and usually from about 40 to about infinity. It will be appreciated
from the permitted values for n that ITQ-13 can be synthesized in
totally siliceous form in which the trivalent element X is absent
or essentially absent.
[0032] Processes for synthesizing ITQ-13 employ fluorides, in
particular HF, as a mineralizing agent and hence, in its
as-synthesized form, ITQ-13 has a formula, on an anhydrous basis
and in terms of moles of oxides per n moles of YO.sub.2, as
follows:
(0.2-0.4)R:X.sub.2O.sub.3:(n)YO.sub.2L(0.4-0.8)F
[0033] wherein R is an organic moiety. The R and F components,
which are associated with the material as a result of their
presence during crystallization, are easily removed by
post-crystallization methods hereinafter more particularly
described.
[0034] To the extent desired and depending on the
X.sub.2O.sub.3/YO.sub.2 molar ratio of the material, any cations in
the as-synthesized ITQ-13 can be replaced in accordance with
techniques well known in the art, at least in part, by ion exchange
with other cations. Preferred replacing cations include metal ions,
hydrogen ions, hydrogen precursor, e.g., ammonium ions and mixtures
thereof. Particularly preferred cations are those which tailor the
catalytic activity for certain hydrocarbon conversion reactions.
These include hydrogen, rare earth metals and metals of Groups IIA,
IIIA, IVA, VA, IB, IIB, IIIB, IVB, VB, VIB, VIIB and VIII of the
Periodic Table of the Elements. For light olefin selectivity,
copper and phosphorus are most preferred.
[0035] The as-synthesized ITQ-13 may be subjected to treatment to
remove part or all of any organic constituent used in its
synthesis. This is conveniently effected by thermal treatment in
which the as-synthesized material is heated at a temperature of at
least about 370.degree. C. for at least 1 minute and generally not
longer than 20 hours. While subatmospheric pressure can be employed
for the thermal treatment, atmospheric pressure is desired for
reasons of convenience. The thermal treatment can be performed at a
temperature up to about 925.degree. C. The thermally treated
product, especially in its metal, hydrogen and ammonium forms, is
particularly useful in the catalysis of certain organic, e.g.,
hydrocarbon, conversion reactions.
[0036] Prior to use in the process of the invention, the ITQ-13 is
preferably dehydrated, at least partially. This can be done by
heating to a temperature in the range of 200.degree. C. to about
370.degree. C. in an atmosphere such as air, nitrogen, etc., and at
atmospheric, subatmospheric or superatmospheric pressures for
between 30 minutes and 48 hours. Dehydration can also be performed
at room temperature merely by placing the ITQ-13 in a vacuum, but a
longer time is required to obtain a sufficient amount of
dehydration.
[0037] The silicate and borosilicate forms of ITQ-13 can be
prepared from a reaction mixture containing sources of water,
optionally an oxide of boron, an oxide of tetravalent element Y,
e.g., silicon, a directing agent (R) as described below and
fluoride ions, said reaction mixture having a composition, in terms
of mole ratios of oxides, within the following ranges:
3 Reactants Useful Preferred YO.sub.2/B.sub.2O.sub.3 at least 5 At
least 40 H.sub.2O/YO.sub.2 2-50 5-20 OH.sup.-/YO.sub.2 0.05-0.7
0.2-0.4 F/YO.sub.2 0.1-1 0.4-0.8 R/YO.sub.2 0.05-0.7 0.2-0.4
[0038] The organic directing agent R used herein is the
hexamethonium [hexamethylenebis(trimethylammonium)] dication and
preferably is hexamethonium dihydroxide. Hexamethonium dihydroxide
can readily be prepared by anion exchange of commercially available
hexamethonium bromide.
[0039] Crystallization of ITQ-13 can be carried out at either
static or stirred conditions in a suitable reactor vessel, such as
for example, polypropylene jars or Teflon.RTM.-lined or stainless
steel autoclaves, at a temperature of about 120.degree. C. to about
160.degree. C. for a time sufficient for crystallization to occur
at the temperature used, e.g., from about 12 hours to about 30
days. Thereafter, the crystals are separated from the liquid and
recovered.
[0040] It should be realized that the reaction mixture components
can be supplied by more than one source. The reaction mixture can
be prepared either batch-wise or continuously. Crystal size and
crystallization time of the new crystalline material will vary with
the nature of the reaction mixture employed and the crystallization
conditions.
[0041] Synthesis of ITQ-13 may be facilitated by the presence of at
least 0.01 percent, preferably 0.10 percent and still more
preferably 1 percent, seed crystals (based on total weight) of
crystalline product.
[0042] The ITQ-13 used in the process of the invention is
preferably an aluminosilicate or boroaluminosilicate and more
preferably has a silica to alumina molar ratio of less than about
1000. Aluminosilicate ITQ-13 can readily be produced from the
silicate and borosilicate forms by post-synthesis methods
well-known in the art, for example by ion exchange of the
borosilicate material with a source of aluminum ions.
[0043] Particularly when employed to crack heavy hydrocarbons
feedstocks, such as those having an initial boiling point of about
200.degree. C., the catalyst composition used in the process of the
invention preferably comprises a large pore molecular sieve having
a pore size greater than 6 Angstrom, and preferably greater than 7
Angstrom, in addition to the 9-member ring catalyst composition of
the present invention. Typically, where the catalyst contains a
large pore molecular sieve, the weight ratio of the 9-member ring
catalyst to the large pore molecular sieve is about 0.005 to 50,
preferably about 0.1 to 1.0.
[0044] The large-pore cracking component may be any conventional
molecular sieve having cracking activity and a pore size greater
than 6 Angstrom including zeolite X (U.S. Pat. No. 2,882,442); REX;
zeolite Y (U.S. Pat. No. 3,130,007); Ultrastable Y zeolite (USY)
(U.S. Pat. No. 3,449,070); Rare Earth exchanged Y (REY) (U.S. Pat.
No. 4,415,438); Rare Earth exchanged USY (REUSY); Dealuminated Y
(DeAl Y) (U.S. Pat. No. 3,442,792; U.S. Pat. No. 4,331,694);
Ultrahydrophobic Y (UHPY) (U.S. Pat. No. 4,401,556); and/or
dealuminated silicon-enriched zeolites, e.g., LZ-210 (U.S. Pat. No.
4,678,765). Zeolite ZK-5 (U.S. Pat. No. 3,247,195); zeolite ZK-4
(U.S. Pat. No. 3,314,752); ZSM-20 (U.S. Pat. No. 3,972,983);
zeolite Beta (U.S. Pat. No. 3,308,069) and zeolite L (U.S. Pat.
Nos. 3,216,789 and 4,701,315), as well as naturally occurring
zeolites such as faujasite, mordenite and the like may also be
used. These materials may be subjected to conventional treatments,
such as impregnation or ion exchange with rare earths to increase
stability. The preferred large pore molecular sieve of those listed
above is a zeolite Y, more preferably an REY, USY or REUSY.
[0045] Other suitable large-pore crystalline molecular sieves
include pillared silicates and/or clays; aluminophosphates, e.g.,
ALPO4-5, ALPO4-8, VPI-5; silicoaluminophosphates, e.g., SAPO-5,
SAPO-37, SAPO-31, SAPO-40; and other metal aluminophosphates. These
are variously described in U.S. Pat. Nos. 4,310,440; 4,440,871;
4,554,143; 4,567,029; 4,666,875; 4,742,033; 4,880,611; 4,859,314;
and 4,791,083.
[0046] The cracking catalyst will also normally contain one or more
matrix or binder materials that are resistant to the temperatures
and other conditions e.g., mechanical attrition, which occur during
cracking. Where the cracking catalyst contains a large pore
molecular sieve in addition to the 9-member ring catalyst
composition, the matrix material may be used to combine both
molecular sieves in each catalyst particle. Alternatively, the same
or different matrix materials can be used to produce separate
particles containing the large pore molecular sieve and the
9-member ring catalyst composition respectively. In the latter
case, the different catalyst components can be arranged in separate
catalyst beds.
[0047] The matrix may fulfill both physical and catalytic
functions. Matrix materials include active or inactive inorganic
materials such as clays, and/or metal oxides such as alumina or
silica, titania, zirconia, or magnesia. The metal oxide may be in
the form of a sol or a gelatinous precipitate or gel.
[0048] Naturally occurring clays that can be employed in the
catalyst include the montmorillonite and kaolin families which
include the subbentonites, and the kaolins commonly known as Dixie,
McNamee, Georgia and Florida clays or others in which the main
mineral constituent is halloysite, kaolinite, dickite, nacrite or
anauxite. Such clays can be used in the raw state as originally
mined or initially subjected to calcination, acid treatment or
chemical modification.
[0049] In addition to the foregoing materials, catalyst can include
a porous matrix material such as silica-alumina, silica-magnesia,
silica-zirconia, silica-thoria, silica-beryllia, silica-titania, as
well as ternary materials such as silica-alumina-thoria,
silica-alumina-zirconia, silica-alumina-magnesia,
silica-magnesia-zirconi- a. The matrix can be in the form of a
cogel. A mixture of these components can also be used.
[0050] In general, the relative proportions of molecular sieve
component(s) and inorganic oxide matrix vary widely, with the
molecular sieve content ranging from about 1 to about 90 percent by
weight, and more usually from about 2 to about 80 weight percent of
the composite.
[0051] The feedstock employed in the process of the invention
comprises one or more hydrocarbons having at least 5 carbon
atoms.
[0052] In one aspect, the feedstock comprises a naphtha. Typically
such feedstocks have a boiling range of about 25.degree. C. to
about 225.degree. C. and preferably a boiling range of 25.degree.
C. to 125.degree. C. The naphtha can be a thermally cracked or a
catalytically cracked naphtha. Such streams can be derived from any
appropriate source, for example, they can be derived from the fluid
catalytic cracking (FCC) of gas oils and resids, or they can be
derived from delayed or fluid coking of resids. It is preferred
that the naphtha streams be derived from the fluid catalytic
cracking of gas oils and resids. Such naphthas are typically rich
in olefins and/or diolefins and relatively lean in paraffins.
[0053] The feedstock could, alternatively, comprise a hydrocarbon
mixture having an initial boiling point of about 200.degree. C. The
hydrocarbon feedstock to be cracked may include, in whole or in
part, a gas oil (e.g., light, medium, or heavy gas oil) having an
initial boiling point above 200.degree. C., a 50 % point of at
least 260.degree. C. and an end point of at least 315.degree. C.
The feedstock may also include vacuum gas oils, thermal oils,
residual oils, gas oil, vacuum gas oil, residual oil vacuum resid,
cycle stocks, whole top crudes, tar sand oils, shale oils,
synthetic fuels, heavy hydrocarbon fractions derived from the
destructive hydrogenation of coal, tar, pitches, asphalts,
hydrotreated feedstocks derived from any of the foregoing, and the
like. As will be recognized, the distillation of higher boiling
petroleum fractions above about 400.degree. C. must be carried out
under vacuum in order to avoid thermal cracking. The boiling
temperatures utilized herein are expressed for convenience in terms
of the boiling point corrected to atmospheric pressure. Resids or
deeper cut gas oils with high metals contents can also be cracked
using the process of the invention. Naphthas and at least one of
gas oil, vacuum gas oil, residual oil vacuum resid are preferred
feedstocks.
[0054] The catalytic cracking process of the invention can operate
at temperatures from about 200.degree. C. to about 870.degree. C.
under reduced, atmospheric or superatmospheric pressure. By way of
non-limiting example, the process total pressure could be about 0.5
to about 10 atmospheres, preferably about 1 to about 3 atmospheres.
The catalytic process can be either fixed bed, moving bed or
fluidized bed and the hydrocarbon flow may be either concurrent or
countercurrent to the catalyst flow. The process of the invention
is particularly applicable to the Fluid Catalytic Cracking (FCC) or
moving bed processes such as the Thermofor Catalytic Cracking (TCC)
processes.
[0055] The TCC process is a moving bed process wherein the catalyst
is in the shape of pellets or beads having an average particle size
of about one sixty-fourth to one-fourth inch. Active, hot catalyst
beads progress downwardly cocurrent with a hydrocarbon charge stock
through a cracking reaction zone. The hydrocarbon products are
separated from the coked catalyst and recovered, whereas the coked
catalyst is removed from the lower end of the reaction zone and
regenerated. Typically TCC conversion conditions include an average
reactor temperature of about 450.degree. C. to about 510.degree.
C.; catalyst/oil volume ratio of about 2 to about 7; reactor space
velocity of about 1 to about 2.5 vol./hr./vol.; and recycle to
fresh feed ratio of 0 to about 0.5 (volume).
[0056] The process of the invention is particularly applicable to
fluid catalytic cracking (FCC), in which the cracking catalyst is
typically a fine powder with a particle size of about 10 to 200
microns. This powder is generally suspended in the feed and
propelled upward in a reaction zone. A relatively heavy hydrocarbon
feedstock, e.g., a gas oil, is admixed with the cracking catalyst
to provide a fluidized suspension and cracked in an elongated
reactor, or riser, at elevated temperatures to provide a mixture of
lighter hydrocarbon products. The gaseous reaction products and
spent catalyst are discharged from the riser into a separator,
e.g., a cyclone unit, located within the upper section of an
enclosed stripping vessel, or stripper, with the reaction products
being conveyed to a product recovery zone and the spent catalyst
entering a dense catalyst bed within the lower section of the
stripper. In order to remove entrained hydrocarbons from the spent
catalyst prior to conveying the latter to a catalyst regenerator
unit, an inert stripping gas, e.g., steam, is passed through the
catalyst bed where it desorbs such hydrocarbons conveying them to
the product recovery zone. The fluidizable catalyst is continuously
circulated between the riser and the regenerator and serves to
transfer heat from the latter to the former thereby supplying the
thermal needs of the cracking reaction which is endothermnic.
[0057] Typically, FCC conversion conditions include a riser top
temperature of about 500.degree. C. to about 650.degree. C.,
preferably from about 500.degree. C. to about 600.degree. C., and
most preferably from about 500.degree. C. to about 550.degree. C.;
catalyst/oil weight ratio of about 3 to about 12, preferably about
4 to about 11, and most preferably about 5 to about 10; and
catalyst residence time of about 0.5 to about 15 seconds,
preferably about 1 to about 10 seconds.
[0058] The invention will now be more particularly described with
reference to the following Examples:
EXAMPLE 1
[0059] A 9-member ring catalyst composition, Borosilicate ITQ-13,
was synthesized from a gel having the following molar
composition:
1 SiO.sub.2: 0.01 B.sub.2O.sub.3: 0.29 R(OH).sub.2: 0.64 HF : 7
H.sub.2O
[0060] where R(OH).sub.2 is hexamethonium dihydroxide and 4 wt % of
the SiO.sub.2 was added as ITQ-13 seeds to accelerate the
crystallization. The hexamethonium dihydroxide employed in the gel
was prepared by direct anionic exchange of commercially available
hexamethonium dibromide using a resin, Amberlite IRN-78, as
hydroxide source.
[0061] The synthesis gel was prepared by hydrolyzing 13.87 g of
tetraethyloethosilicate (TEOS) in 62.18 g of a 0.006M hexamethonium
dihydroxide solution containing 0.083 g of boric acid. The
hydrolysis was effected under continuous mechanical stirring at 200
rpm, until the ethanol and an appropriate amount of water were
evaporated to yield the above gel reaction mixture. After the
hydrolysis step, a suspension of 0.16 g of as-synthesized ITQ-13 in
3.2 g of water was added as seeds and then a solution of 1.78 g of
HF (48 wt % in water) and 1 g of water were slowly added to produce
the required reaction mixture. The reaction mixture was
mechanically and finally manually stirred until a homogeneous gel
was formed. The resulting gel was very thick as a consequence of
the small amount of water present. The gel was autoclaved at
135.degree. C. for 21 days under continuous tumbling at 60 rpm. The
pH of the final gel (prior of filtration) was 6.5-7.5. The solid
was recovered by filtration, washed with distilled water and dried
at 100.degree. C., overnight. The occluded hexamethonium and
fluoride ions were removed from the product by heating the product
from room temperature to 540.degree. C. at 1.degree. C./min under
N.sub.2 flow (60 ml/mm). The temperature was kept at 540.degree. C.
under N.sub.2 for 3 hours and then the flow was switched to air and
the temperature kept at 540.degree. C. for a further 3 hours in
order to burn off the remaining organic. X-ray analysis showed the
calcined product to be ITQ-13 containing some ZSM-50 impurity,
whereas boron analysis indicated the Si/B atomic ratio of the final
solid to be about 60.
[0062] Aluminum-containing ITQ-13 was prepared using ion exchange
by suspending, under stirring, 0.74 g of the calcined B-ITQ-13 in
10.5 g of an aqueous Al(NO.sub.3).sub.3 solution containing 8 wt %
Al(NO.sub.3).sub.3 and then transferring the resultant suspension
to an autoclave, where the suspension was heated at 135.degree. C.
for 3 days under continuous stirring at 60 rpm. The resulting solid
was filtered, washed with distilled water until the water was at
neutral pH and dried at 1 00.degree. C., overnight. Chemical
analysis indicated the product to have a Si/Al atomic ratio of 80
and a Si/B atomic ratio greater than 500.
Example 2
[0063] Five separate catalysts were prepared from (a) the
aluminum-containing ITQ-13 from Example 1, (b) ZSM-5, (c)
ferrierite (FER) (d) a commercially available USY having a unit
cell size of 2.432 nm and (e) a commercially available USY having a
unit cell size of 2.426 nm. The properties of the various zeolites
employed were as follows:
4 USY USY Zeolite ZSM-5 ITQ-13 FER 2.432 nm 2.426 nm Surface Area,
m.sup.2/g 385 354 280 641 551 Crystal Size, micron 0.5-1 0.1-0.3
1-3 0.5 0.5 Si/Al atomic area 43 80 60 19* 62* Bronsted Activity
(.mu.mol Py/g) T = 523.degree. K. 40 18 21 77 14 T = 623.degree. K.
26 12 14 45 3 T = 673.degree. K. 7 5 5 28 1 Lewis Activity (.mu.mol
Py/g) T = 523.degree. K. 6 8 2 9 10 T = 623.degree. K. 5 6 1 8 7 T
= 673.degree. K. 5 6 1 7 4 *= after steaming
[0064] Each of catalysts (a) to (c) contained 0.5 gm of the zeolite
diluted with 2.5 gm of inert silica, whereas each of catalysts (d)
and (e) contained 1.20 gm of USY diluted with 0.30 gm of inert
silica.
EXAMPLE 3
[0065] The catalysts containing ITQ-13 and ZSM-5 produced in
Example 2 were used to crack hexene-1 and 4-methylpentene-1 in a
conventional Microactivity Test Unit (MAT) at 500.degree. C., 60
seconds time on stream, and catalyst to oil ratios (w/w) of
0.3-0.7. Gases were analyzed by gas chromatography in a HP 5890
Chromatograph with a two-column system in series using argon as the
camrer gas. Hydrogen, nitrogen and methane were separated in a 15 m
long, 0.53 mm internal diameter molecular sieve 5A column and
thermal conductivity detector. C.sub.2 to C.sub.5 hydrocarbons were
separated in a 50 m long, 0.53 mm internal diameter alumina plot
column and flame ionization detector. Liquids were analyzed in a
Varian 3400 with a 100 m long, 0.25 mm internal diameter Petrocol
DH column.
[0066] The results of cracking the two olefins are shown below in
Tables 3 and 4. These have been estimated at constant conversion by
fitting the individual component analyses over the range of
catalyst/oil ratios used in the experiments to suitable polynomials
and interpolated at a central point. It will be seen from Tables 3
and 4 that the 9-member ring catalyst composition (containing
ITQ-13) provided much higher yields of propylene (20.86 wt % for
hexene-1 and 19.7 wt % for 4-methylpentene-1) than the catalyst
containing ZSM-5 (11.91 wt % for hexene-1 and 11.21 wt % for
4-methylpentene-1). Moreover the 9-member ring catalyst composition
provided much higher ratios of propylene to propane (35 for
hexene-1 and 22 for 4-methylpentene-1) than the catalyst containing
ZSM-5 (6 for hexene-1 and 7 for 4-methylpentene-1).
5 TABLE 3 CATALYST ZSM-5 ITQ-13 Feed Hexane-1 Hexene-1 Cat/Oil 0.05
0.09 Conversion, wt % 54 54 Liquids, wt % 25.81 18.37 Gases, wt %
27.85 34.81 Coke, wt % 0.35 0.53 H.sub.2, wt % 0.01 0.003 C1, wt %
0.04 0.06 C2, wt % 0.13 0.14 C2.dbd., wt % 2.67 2.43 C3, wt % 1.70
0.60 C3.dbd., wt % 11.91 20.86 iC4, wt % 1.54 0.50 nC4, wt % 0.73
0.20 t2C4.dbd., wt % 1.81 2.14 IC4.dbd., wt % 1.94 2.07 iC4.dbd.,
wt % 3.88 3.86 c2C4.dbd., wt % 1.48 1.74
[0067]
6 TABLE 4 CATALYST ZSM-5 ITQ-13 Feed 4-methylpentene-1
4-methylpentene-1 Cat/Oil 0.05 0.09 Conversion, wt % 9.00 49.00
Liquids, wt % 21.84 16.03 Gases, wt % 26.82 32.31 Coke, wt % 0.34
0.67 H2, wt % 0.01 0.009 C1, wt % 0.05 0.10 C2, wt % 0.07 0.06
C2.dbd., wt % 2.33 2.02 C3, wt % 1.65 0.88 C3.dbd., wt % 11.21
19.17 iC4, wt % 1.47 0.60 nC4, wt % 0.72 0.18 t2C4.dbd., wt % 1.84
2.03 IC4.dbd., wt % 1.95 1.94 iC4.dbd., wt % 3.95 3.76 c2C4.dbd.,
wt % 1.55 1.66
EXAMPLE 4
[0068] The use of the ITQ-13, ZSM-5 and FER catalysts of Example 2
as additives to the USY cracking catalysts of Example 2 in the
cracking of a vacuum gas oil were studied in a similar MAT unit to
that used in Example 3. The USY and additive catalysts were placed
in separate beds. The top bed contained the
[0069] USY zeolite and the bottom bed contained the zeolite
additive diluted in 1.10 gm of silica. The properties of the vacuum
gas oil used are given in Table 5.
7 TABLE 5 Density (15.degree. C.) g/cc 0.917 Aniline Point
(.degree. C.) 79.2 S (wt %) 1.65 N, ppm 1261 Na, ppm 0.18 Cu, PPM
<0.1 Fe, ppm 0.3 Ni, ppm 0.2 V, ppm 0.4 ASTM D-1 160 (.degree.
C.) 5% 319 10% 352 30% 414 50% 436 70% 459 90% 512
[0070] The results of the tests are shown in Tables 6 to 9 below.
FIGS. 4 and 5 summarize the overall product make with the different
USY catalysts, both alone and with the various additive catalysts,
whereas Tables 8 and 9 summarize the results of analysis of the
gasoline fractions obtained in each test. In the Tables, the first
data column shows the results with the USY alone, whereas the data
in the columns under the additive zeolites show the results when
the additives were used. The percent of additive used corresponds
to the weight of additive per 100 g USY zeolite. The catalyst/oil
ratios are based on USY only. Estimates were made at constant 75 wt
% conversion in the manner described above.
8TABLE 6 CATALYST USY (2.432 nm) ZSM-5 (20%) ITQ-13 (20%) Cat/Oil
0.69 0.48 0.50 Gasoline, wt % 41.95 34.57 36.82 Diesel, wt % 14.56
11.77 12.61 Gases, wt % 12.53 21.83 18.69 Coke, wt % 1.46 1.82 1.38
Gas Yields, wt % H.sub.2 0.07 0.03 -0.03 C1 0.41 0.19 0.53 C2.dbd.
0.80 1.59 1.18 C3 1.19 3.19 2.14 C3.dbd. 2.32 5.17 4.45 iC4 3.88
4.82 4.46 nC4 0.89 1.81 1.41 t2C4.dbd. 0.67 1.00 0.80 IC4.dbd. 0.85
0.82 1.03 iC4.dbd. 0.82 2.02 1.93 c2C4.dbd. 0.63 0.97 0.63
Butene/Butane ratio 0.62 0.72 0.75 Propylene/Propane 1.95 1.62 2.08
ratio
[0071]
9TABLE 7 USY ZSM-5 ITQ-13 CATALYST (2.426 nm) (20%) (20%) FER (20%)
Cat/Oil 1.13 0.74 1.10 1.49 Gasoline, wt % 39.23 34.36 37.87 38.53
Diesel, wt % 13.10 12.04 13.08 13.19 Gases, wt % 15.64 22.05 17.53
16.46 Coke, wt % 2.03 1.55 1.52 1.32 Gas Yields, wt % H.sub.2 0.03
0.04 0.03 0.04 C1 0.63 0.57 0.29 0.34 C2 0.59 0.58 0.26 0.23
C2.dbd. 1.00 1.81 0.85 1.17 C3 1.47 2.40 1.04 1.33 C3.dbd. 3.41
5.65 5.15 3.99 iC4 4.61 3.88 3.66 4.34 nC4 1.04 1.21 0.94 1.03
t2C4.dbd. 0.92 1.02 1.09 0.97 IC4.dbd. 0.95 1.27 0.58 1.21 iC4.dbd.
1.13 2.41 2.02 1.40 c2C4.dbd. 0.77 1.07 1.18 0.80 Butene/Butane
0.67 1.13 1.06 0.82 Propylene/Propane 2.32 2.35 4.95 3.00
[0072]
10TABLE 8 BASE CATALYST USY 2.432 nm + USY 2.432 nm + CATALYST (USY
2.432 nm) 20% ZSM-5 20% ITQ-13 n-Paraffins 4.2 4.6 5.1 i-Paraffins
26.4 21.3 23.4 Olefins 9.1 6.1 7.0 Naphthenes 12.0 9.7 11.0
Aromatics 48.3 58.2 53.5 RON 87 88.5 88.2 MON 83.1 84.7 83.8
Isoamylenes 0.58 0.80 0.83
[0073]
11TABLE 9 BASE CATALYST USY 2.426 nm + USY 2.426 nm + CATALYST (USY
2.426 nm) 20% ZSM-5 20% ITQ-13 n-Paraffins 4.0 4.8 4.9 i-Paraffins
22.2 18.5 20.5 Olefins 8.9 6.5 8.3 Naphthenes 11.6 9.2 9.8
Aromatics 53.4 61.0 45.6 RON 87.4 89.2 88.2 MON 83.1 84.7 83.7
Isoamylenes 0.45 0.60 0.81
[0074] It can be seen from Tables 6 and 7 that the 9-member ring
catalyst composition in accordance with the present invention
provides much lower yields of propane and butane than the catalysts
containing ZSM-5 and FER, so that the propylene/propane ratio and
the butene/butane ratio are higher with the 9-member ring catalyst
composition than for the ZSM-5 and FER catalysts. Moreover, it can
be seen from Tables 8 and 9 that addition of the 9-member ring
catalyst composition additive to the USY cracking catalysts gave an
increase in the octane number (both RON and MON) of the gasoline
produced, although this increase was somewhat less than that
obtained with the ZSM-5 additive.
EXAMPLE 5
[0075] To illustrate the effectiveness of 9-member ring catalyst in
accordance with the present invention as additive for a fluid
catalytic cracker, back-to-back experiments were carried out
comparing a 9-member ring catalyst composition in accordance with
the present invention to ZSM-5. The ZSM-5 was OlefinsMax. These
experiment were carried out in a fixed fluidized bed reactor with
vacuum gas oil (VGO) gas feed. In this series of experiments,
OlefinsMax was steamed at 1500.degree. F. for 16 hours to simulate
commercial equilibration. The 9-member ring catalyst composition
was ITQ-13, which was tested fresh.
[0076] The propylene selectivity for the ITQ-13 catalyst was 15%
higher than that of the OlefinsMax catalyst. Its relative activity
was also high at 1.4. This meant that the inventive catalyst was
40% more active than the OlefinsMax catalyst.
[0077] In addition to being active and selective, the ITQ-13
catalyst could also be stabilized. In bench unit testing with a
50/50 blend of hexane and hexane model compounds, copper modified
ITQ-13 showed 35-42 weight % C.sub.4.sup.- conversion. This was a
35-50% improvement in catalyst activity as compared to untreated
catalyst, which was steamed under nominally identical conditions
(1400.degree. F. for 2 hours). Further, the selectivity of the
stabilized catalyst was significantly higher than that of the
untreated catalyst.
EXAMPLE 6
[0078] To a perfluoroalkoxy-Teflon (PFA) bottle were added 300
grams Syton HT-50 silica (Aldrich), 3.09 grams of boric acid, 78.05
grams of 54.9 weight % of hexamethonium hydroxide solution, 93.9
grams of N,N,N',N'-tetramethylhexane-1,6-diamine, 109.4 grams of 48
weight % HF, and 6.01 grams of ITQ-13 seeds. The bottle was shaken
for 30-minutes. The pH was found to be 7.3. The bottle was placed
into a 2 liter autoclave and heated at 1.degree. C. per minute to
135.degree. C, and held at 135.degree. C. for 21 days. At the end
of this time, the pH was found to be 7.1. The solid was filtered,
washed copiously with water and dried to constant weight at
80.degree. C. The yield was 151.9 grams. An X-ray powder
diffraction pattern for the as-synthesized 9-member ring zeolite is
shown in FIG. 5.
[0079] The as-synthesized material was calcined as a thin layer
(.about.1 gram per square centimeter) by ramping under N.sub.2,
2.degree. C. per minute, to 230.degree. C., holding for 2 hours,
ramping at 2.degree. C. per minute to 540.degree. C. and holding
for 8 hours. The gas was then switched to dry air, and the sample
held 8 hours at 540.degree. C., then cooled under dry air. An X-ray
powder diffraction pattern for the calcined 9-member ring zeolite
is shown in FIG. 6.
[0080] The calcined material was converted from the boron to the
aluminum form by mixing 45 grams calcined ITQ-13, 98.3 grams
Al(NO.sub.3).sub.3.H.sub.2O. and 540 grams of H.sub.2O in a PFA
bottle. The bottle was placed in a 2 liter autoclave and heated at
1.degree. C. per minute to 135.degree. C. and held at that
temperature for 3 days. The product was filtered, washed with
H.sub.2O until the washings had a pH>5, then dried to constant
weight at 80.degree. C. The yield was 43 grams. An X-ray powder
diffraction pattern for the 9-member ring zeolite after aluminum
insertion is shown in FIG. 7.
EXAMPLE 7
[0081] ITQ-13 crystals (powder) were pelletized into 40-60 mesh
granules using the conventional press-and-sieve technique. The
catalyst was loaded into a fixed-bed stainless steel microreactor
and was activated in flowing nitrogen at 550.degree. C. for 30
minutes before a 50:50 mixed 1-hexene and n-hexane feed was
introduced over the catalyst using a micro syringe pump. The
reactor pressure was 15 psig. The reactor effluent was analyzed
with an on-line Gas Chromatograph equipped with a FID detector, at
fixed on-stream feed intervals. The feed rate and the weight of
catalyst loading (WHSV) were adjusted to obtain comparable initial
feed conversion.
[0082] The results (shown in Table 10 below) show that the 9-member
ring catalyst composition has notably stable on-stream catalytic
activity, with a conversion to C4.sup.- products of about 42%. The
propylene selectivity is attractive, at about 65%, and the
propylene/propane ratio is around 20.
[0083] There was some reason to believe that the sample of ITQ-13
used in this example contained about 1.7 wt % ZSM-50 impurity.
Applicants tested a catalyst consisting of 5% ZSM-50 in alumina for
comparison. The ZSM-50 level in this reference catalyst is about 3
times higher than the estimated amount in the ITQ-13 sample, so the
WHSV for the reference catalyst was tripled to 780 hr.sup.-1. The
reference catalyst showed about 42% conversion after the first
minute on stream, but with low (49%) selectivity to propylene.
Conversion dropped rapidly, to 37% after 2 minutes and 23% after 4
minutes. Thus the activity of this ITQ-13 sample could not be
attributed solely to 1-2 wt % ZSM-50 impurities.
12TABLE 10 ITQ-13 WHSV 260 hr.sup.-1 Time, minutes 3 6 9 13 15 g
feed/g catalyst 13 26 39 56.33 65 C.sub.4.sup.- conversion, % 42.55
42.43 42.41 42.36 42.17 Product yield, wt % C.sub.1 + C.sub.2 0.39
0.37 0.37 0.4 0.38 C.sub.3 1.61 1.42 1.39 1.45 1.26
C.sub.2.sup..dbd. 3.42 3.29 3.25 3.31 3.22 C.sub.3.sup..dbd. 26.59
27.31 27.71 27.4 27.78 C.sub.4's 0.43 0.35 0.3 0.31 0.28
C.sub.4.sup..dbd.'s 10.11 9.69 9.39 9.49 9.25 Total C.sub.4.sup.-
42.55 42.43 42.41 42.36 42.17 Selectivity, wt % C.sub.1 + C.sub.2
0.92 0.87 0.87 0.94 0.90 C.sub.3 3.78 3.35 3.28 3.42 2.99
C.sub.2.dbd. 8.04 7.75 7.66 7.81 7.64 C.sub.3.sup..dbd. 62.49 64.36
65.34 64.68 65.88 C.sub.4's 1.01 0.82 0.71 0.73 0.66
C.sub.4.sup..dbd.'s 23.76 22.84 22.14 22.40 21.94
* * * * *