U.S. patent application number 13/272291 was filed with the patent office on 2012-03-22 for toluene disproportionation using nb/mordenite catalyst.
This patent application is currently assigned to Fina Technology, Inc.. Invention is credited to James R. Butler, Rosa Hall, Xin Xiao.
Application Number | 20120071317 13/272291 |
Document ID | / |
Family ID | 41681722 |
Filed Date | 2012-03-22 |
United States Patent
Application |
20120071317 |
Kind Code |
A1 |
Butler; James R. ; et
al. |
March 22, 2012 |
TOLUENE DISPROPORTIONATION USING Nb/MORDENITE CATALYST
Abstract
A molecular sieve catalyst useful in the conversion of
hydrocarbons containing niobium is disclosed, along with a process
for the disproportionation of toluene to benzene and xylene using
such catalyst.
Inventors: |
Butler; James R.; (League
City, TX) ; Hall; Rosa; (Houston, TX) ; Xiao;
Xin; (Augusta, GA) |
Assignee: |
Fina Technology, Inc.
Houston
TX
|
Family ID: |
41681722 |
Appl. No.: |
13/272291 |
Filed: |
October 13, 2011 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
12193685 |
Aug 18, 2008 |
8063259 |
|
|
13272291 |
|
|
|
|
Current U.S.
Class: |
502/78 ; 502/353;
502/60 |
Current CPC
Class: |
C07C 2529/26 20130101;
C07C 6/123 20130101; C07C 6/123 20130101; B01J 29/26 20130101; Y02P
20/52 20151101; C07C 15/04 20130101; B01J 29/076 20130101; C07C
6/123 20130101; C07C 15/06 20130101 |
Class at
Publication: |
502/78 ; 502/353;
502/60 |
International
Class: |
B01J 29/26 20060101
B01J029/26; B01J 29/04 20060101 B01J029/04; B01J 29/00 20060101
B01J029/00 |
Claims
1. A catalyst useful in the conversion of hydrocarbons comprising:
a molecular sieve catalyst containing niobium.
2. The catalyst of claim 1, wherein the molecular sieve catalyst is
a zeolite.
3. The catalyst of claim 1, wherein the molecular sieve catalyst is
a mordenite zeolite.
4. The catalyst of claim 1, wherein the catalyst is used in a
toluene disproportionation reaction process.
5. The catalyst of claim 4, wherein the toluene disproportionation
reaction process provides a toluene conversion at a rate of at
least 30 wt % and non-aromatic selectivity of less than 1.0 wt
%.
6. The catalyst of claim 4, wherein the toluene disproportionation
reaction process provides a toluene conversion at a rate of at
least 40 wt % and non-aromatic selectivity of less than 0.5 wt
%.
7. The catalyst of claim 4, wherein the toluene disproportionation
reaction process can continue with a toluene conversion of at least
30 percent for at least 30 days with an average catalyst
deactivation no more than 1.0.degree. C./day.
8. The catalyst of claim 4, wherein the toluene disproportionation
reaction process can continue with a toluene conversion of at least
40 percent for at least 30 days with an average catalyst
deactivation no more than 0.5.degree. C./day.
9. The catalyst of claim 1, wherein the molecular sieve catalyst
contains at least 0.005 wt % niobium.
10. The catalyst of claim 1, wherein the toluene disproportionation
reaction process provides a toluene conversion at a rate of at
least 30 wt % and the methylcyclopentane content is less than 0.005
wt % of the liquid effluent.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] Not applicable.
FIELD
[0002] This invention relates to the disproportionation of
alkylaromatic feedstreams.
BACKGROUND
[0003] The disproportionation of toluene involves a well known
transalkylation reaction in which toluene is converted to benzene
and xylene, often referred to as a Toluene Disproportionation
Process or TDP, in accordance with the following reaction:
Toluene Disproportionation: Toluene.rarw. .fwdarw.Benzene+Xylene
(1)
[0004] Mordenite is one of a number of molecular sieve catalysts
useful in the transalkylation of alkylaromatic compounds. Mordenite
is a crystalline aluminosilicate zeolite exhibiting a network of
silicon and aluminum atoms interlinked by oxygen atoms within the
crystalline structure. For a general description of mordenite
catalysts, reference is made to Kirk-Othmer, Encyclopedia of
Chemical Technology, 3rd Edition, 1981, under the heading
"Molecular Sieves", Vol. 15, pages 638-643, which is incorporated
by reference herein. Mordenite, as found in nature or as
synthesized to replicate the naturally occurring zeolite, typically
exhibits a relatively low silica-to-alumina mole ratio of about 10
or less. Also known, however, are mordenite catalysts exhibiting
substantially lower alumina content. These alumina deficient
mordenite catalysts exhibit silica-to-alumina ratios greater than
10, ranging up to about 100, and may be prepared by direct
synthesis as disclosed, for example, in U.S. Pat. No. 3,436,174 to
Sand or by acid extraction of a more conventionally prepared
mordenite as disclosed in U.S. Pat. No. 3,480,539 to Voorhies et
al, both of which are incorporated by reference herein. Both the
typical and the aluminum deficient mordenites are known to be
useful in the disproportionation of toluene.
[0005] Disproportionation of toluene feedstock may be performed at
temperatures ranging from 200.degree. C. to 600.degree. C. or above
and at pressures ranging from atmospheric to 100 atmospheres or
above and at liquid hourly space velocities (LHSV) of around 1 to
10 hr.sup.-1, The specific catalyst, however, may impose
constraints on reaction temperatures in terms of catalyst activity
and aging characteristics. In general relatively high temperatures
are used when employing the high aluminum mordenites (low
silica-to-alumina ratios) and somewhat lower temperatures when
employing the low alumina mordenites. Accordingly, where mordenite
catalysts exhibiting high silica/alumina ratios have been employed
in the transalkylation of alkylaromatics, it has been the practice
to operate toward the lower end of the temperature range.
[0006] Hydrogen is generally supplied along with toluene to the
reaction zone. While the disproportionation reaction (1) does not
involve chemical consumption of hydrogen, the use of a hydrogen
co-feed is generally considered to prolong the useful life of the
catalyst. The amount of hydrogen supplied, which normally is
measured in terms of the hydrogen/toluene mole ratio, is generally
shown in the prior art to increase as temperature increases. The
hydrogen:toluene mole ratio can generally range from 0.05:1 to
5:1.
[0007] Nickel-Mordenite TDP catalysts can have good activity and
selectivity, but at times produce more non-aromatic compounds than
desired. In view of the above, it would be desirable to have a
process of conducting toluene disproportionation with a mordenite
catalyst with lower production of non-aromatic compounds.
SUMMARY
[0008] An embodiment of the present invention is a molecular sieve
catalyst containing niobium useful in the conversion of
hydrocarbons. The niobium content can be at least 0.05 wt %. The
molecular sieve catalyst can be a zeolite, and can be a mordenite
zeolite. The catalyst can be used in a toluene disproportionation
reaction process and can provide a toluene conversion at a rate of
at least 30 wt % and non-aromatic selectivity of less than 1.0 wt
%. The toluene disproportionation reaction process can continue
with a toluene conversion of at least 30 percent for at least 30
days with an average catalyst deactivation no more than 1.0.degree.
C./day. The toluene disproportionation reaction process can provide
a toluene conversion of at least 30 wt % with a methylcyclopentane
content of less than 0.005 wt % of the liquid effluent.
[0009] An alternate embodiment of the present invention is a
process for disproportionation of toluene to benzene and xylene
that includes passing a toluene/hydrogen feedstock over a
niobium-mordenite catalyst at reaction conditions sufficient to
provide toluene conversion at a rate of at least 30 percent and
provide non-aromatic selectivity of less than 1.0 wt %. The niobium
content of the catalyst can be between 0.005 wt % to 3.0 wt %.
[0010] In one embodiment the toluene disproportionation reaction
process can continue with a toluene conversion of at least 30
percent for at least 30 days with an average catalyst deactivation
no more than 1.0.degree. C./day. In an alternate embodiment the
toluene disproportionation reaction process can continue with a
toluene conversion of at least 40 percent for at least 30 days with
an average catalyst deactivation no more than 0.5.degree. C./day.
The reaction temperature can be adjusted to maintain the toluene
conversion level of at least 40 percent. The methylcyclopentane
content can be less than 0.005 wt % of the liquid effluent.
[0011] In yet another embodiment of the present invention a process
for disproportionation of toluene to benzene and xylene includes
passing a toluene/hydrogen feedstock over a niobium-mordenite
catalyst with a niobium content of the catalyst is at least 0.05 wt
%. The reaction conditions are sufficient to provide toluene
conversion at a rate of at least 30 percent and include a reaction
temperature between 150.degree. C. and 471.degree. C. (300.degree.
F.-880.degree. F.) and reaction pressure between 200 psig to 800
psig. The non-aromatic selectivity is less than 0.75 wt % and the
process is capable of such conversion for at least 30 days with an
average catalyst deactivation no more than 1.0.degree. C./day.
BRIEF DESCRIPTION OF DRAWINGS
[0012] FIG. 1 is a graph of toluene conversion and bed temperature
for a TDP reaction using a Nb/Mordenite catalyst.
[0013] FIG. 2 is a graph of the aromatic and liquid nonaromatic
selectivity from the TDP reaction using a Nb/Mordenite catalyst
without sulfiding.
[0014] FIG. 3 graphically shows the breakdown of C5+ nonaromatics
obtained from the TDP reaction using a Nb/Mordenite catalyst.
[0015] FIG. 4 graphically shows a comparison of results between the
in-house prepared Nb/Mordenite catalyst, a commercial H-Mordenite,
and a commercial Ni/Mordenite when tested using an ammonium
temperature programmed desorption (NH.sub.3-TDP) procedure.
[0016] FIG. 5 is a graph of toluene conversion and bed temperature
for a TDP reaction using a commercial Ni/Mordenite catalyst with
sulfiding.
DETAILED DESCRIPTION
[0017] The use of Ni/Mordenite molecular sieve catalysts in toluene
disproportionation and heavy aromatic conversion reactions is well
known in the art. The present invention provides an improved means
of conducting these reactions wherein the nonaromatic selectivity
is comparable or lower than the currently used Ni/Mordenite
catalyst, even without sulfiding.
[0018] In accordance with the present invention, there is provided
a novel process for the disproportionation of toluene over a metal
promoted molecular sieve catalyst in which a Niobium-modified
Mordenite catalyst is used, resulting in low amounts of
nonaromatics.
[0019] One embodiment of the present invention is a molecular sieve
catalyst containing niobium useful in the conversion of
hydrocarbons. In an embodiment the molecular sieve catalyst
contains at least 0.005 wt % niobium. In alternate embodiments the
molecular sieve catalyst contains at least 0.05 wt % niobium or at
least 0.5 wt % niobium. The molecular sieve catalyst can be a
zeolite, and can be a mordenite zeolite. The catalyst can be used
in a toluene disproportionation reaction process and can provide a
toluene conversion at a rate of at least 30 wt % and non-aromatic
selectivity of less than 1.0 wt %, or in an alternate embodiment at
least 40 wt % and non-aromatic selectivity of less than 0.5 wt %.
The toluene disproportionation reaction process can continue with a
toluene conversion of at least 30 percent for at least 30 days with
an average catalyst deactivation no more than 1.0.degree. C./day,
or in an alternate embodiment a toluene conversion of at least 40
percent for at least 30 days with an average catalyst deactivation
no more than 0.5.degree. C./day. The toluene disproportionation
reaction process can provide a toluene conversion rate of at least
30 wt % and a methylcyclopentane content of less than 0.005 wt % of
the liquid effluent.
[0020] An alternate embodiment of the present invention is a
process for disproportionation of toluene to benzene and xylene
that includes passing a toluene/hydrogen feedstock over a
niobium-mordenite catalyst at reaction conditions sufficient to
provide toluene conversion at a rate of at least 30 percent and
provide non-aromatic selectivity of less than 1.0 wt %. The niobium
content of the catalyst can be between 0.005 wt % to 3.0 wt %. In
an embodiment of the invention the toluene conversion is at least
40 percent. The non-aromatic selectivity can be less than 0.5 wt %.
The methylcyclopentane content of the liquid effluent can be less
than 0.005 wt %.
[0021] In one embodiment the toluene disproportionation reaction
process can continue with a toluene conversion of at least 30
percent for at least 30 days with an average catalyst deactivation
no more than 1.0.degree. C./day. In an alternate embodiment the
toluene disproportionation reaction process can continue with a
toluene conversion of at least 40 percent for at least 30 days with
an average catalyst deactivation no more than 0.5.degree. C./day.
The reaction temperature can be adjusted to maintain the toluene
conversion level of at least 40 percent.
[0022] The reaction temperature can range from 150.degree.
C.-471.degree. C. (300.degree. F.-880.degree. F.). The
hydrogen:toluene molar ratio can be between 0.05:1 to 4:1. The
reaction pressure can range between 200 psig to 800 psig.
[0023] In yet another embodiment of the present invention a process
for disproportionation of toluene to benzene and xylene includes
passing a toluene/hydrogen feedstock over a niobium-mordenite
catalyst with a niobium content of the catalyst is at least 0.05 wt
%. The reaction conditions are sufficient to provide toluene
conversion at a rate of at least 30 percent and include a reaction
temperature between 150.degree. C. and 471.degree. C. (300.degree.
F.-880.degree. F.) and reaction pressure between 200 psig to 800
psig. The non-aromatic selectivity is less than 0.75 wt % and the
process is capable of such conversion for at least 30 days with an
average catalyst deactivation no more than 1.0.degree. C./day.
EXAMPLE
[0024] In one experiment a Zeolyst Mordenite Extrudate CPX51, from
Zeolyst International of Valley Forge, Pa., USA, was used as the
base material and was impregnated with 1.914 wt % Niobium using a
wetness incipient method according to the following procedure:
[0025] 1. The catalyst was dried at 110.degree. C. over night. Its
void volume was then measured by filling with deionized water and
was calculated as 0.45 ml/g. [0026] 2. 3.2703 grams of NbCl.sub.5
salt was dissolved in 33.8 ml to make an aqueous solution. [0027]
3. The Nb solution was impregnated to the dried catalyst by
insipient wetness method. [0028] 4. The impregnated catalyst was
dried at between 20.degree. C. to 30.degree. C., then dried further
at 110.degree. C. Later it was calcined at 550.degree. C. for 2
hrs. The dried catalyst was measured to have 1.914 wt % Niobium
content.
[0029] The impregnated catalyst was evaluated in a lab scale
reactor for disproportionation of toluene to benzene and xylene.
The testing conditions are summarized as following.
TABLE-US-00001 Niobium - Mordenite catalyst prepared in-house
Reactor - down flow Nb 1.9 wt % Feed Toluene LHSV 3/hr H2/HC molar
ratio 1:1 then 3:1 when NA are below 1%. Temperature Adjusted to
hold constant conversion RX Inlet Pressure 600 psig Target
conversion 47 .+-. 1% (53% toluene in effluent) Catalyst volume 30
ml, 14-20 mesh without dilution
[0030] The reactor was flushed with flowing nitrogen for 15 minutes
and pressure checked. It was switched to hydrogen flow at 1 L/min
and the pressure increased to 600 psig. The temperature was ramped
at 50.degree. C./h to 200.degree. C. (392.degree. F.) and held
overnight. The following morning it was ramped at a rate of
50.degree. C./hr to 250.degree. C. (485.degree. F.) and held for
two hours. The hydrogen flow was decreased from 1 L/min to a 1:1
hydrogen to hydrocarbon ratio. The temperature was ramped at
6.degree. C./h to 350.degree. C. (662.degree. F.) after the feed
was switched to toluene. Then the temperature was adjusted slowly
during the following 2-3 days to achieve 47% conversion of toluene
(about 360.degree. C. or 680.degree. F.). After the nonaromatics
content in the product fell below 1%, the hydrogen ratio to
hydrocarbon was increased to 3:1. The first sample showed very low
liquid nonaromatics, at 0.5% on day 1 and then below 0.4% even
without sulfiding during startup. Therefore the hydrogen rate was
increased to 3:1 hydrogen to hydrocarbon ratio.
[0031] FIG. 1 shows the toluene conversion and bed temperature
during the study of the disproportionation of toluene to benzene
and xylene using the Nb-Mordenite catalyst. The bed temperature
decreased for a few days early in the study due to an unplanned
shutdown. At Day 13 after a stabilization period the conversion
maintained at approximately 47% with minor temperature adjustments
and the deactivation rate (temperature rise) was approximately
0.37.degree. F./day (0.21.degree. C./day) with an average bed
temperature of 760.degree. F. (404.degree. C.).
[0032] FIG. 2 shows the aromatic selectivity for the aromatic
products of benzene, xylene and heavy aromatics, along with liquid
nonaromatics from the study. The liquid nonaromatics were very low
at 0.5% on day 1, and then below 0.4% throughout the study, even
without sulfiding during startup. The aromatic selectivity's were
within expected ranges, on average 38.8% for benzene, 49.1% for
xylenes and 10.4% for heavies.
[0033] FIG. 3 shows the breakdown of the C5+ nonaromatic product.
The methylcyclopentane (MCP) content is less than 0.004 wt % of the
liquid effluent, which is lower than the Ni/Mordenite catalysts
that have been tested, as can be seen in Table 4. MCP has
essentially the same boiling point as benzene, making it difficult
to isolate and remove. There is a desire to minimize the creation
of MCP for this reason. The major constituents of the C5+
nonaromatic product are each less than 0.010 wt % of the liquid
effluent, and include isopentane, pentane, cyclopentane and others
as shown.
[0034] FIG. 4 is a NH3-TDP graph (ammonium temperature programmed
desorption) comparison between the in-house prepared Nb/Mordenite
catalyst of the present invention and two commercial catalysts, an
H-Mordenite (Zeolyst CP-X51) and Ni/Mordenite (Zeolyst CP-751). The
acidity of Nb/Mordenite is slightly lower than the H-Mordenite
catalyst and is substantially lower than the Ni/Mordenite catalyst.
The lower acidity indicates fewer active acid sites and is thought
to be why the Nb/Mordenite catalyst required a much higher bed
temperature (.about.90+.degree. F., .about.50+.degree. C.) for the
TDP reaction.
[0035] The Nb/Mordenite showed high activity and stability for TDP
conversion with low nonaromatic production. In this particular
study the activity was stable around 760.degree. F. (404.degree.
C.). The quantity of nonaromatic compounds in the product with the
Nb/Mordenite catalyst without sulfiding was comparable with results
from the Ni/Mordenite type TDP catalyst with sulfiding. Elimination
of the need for sulfiding can reduce cost and may enable shorter
start-up times and achieve on-spec products in a shorter amount of
time after start-up.
[0036] The following Table 1 and 2 give experimental data from the
Experiment for the disproportionation of toluene to benzene and
xylene using the Nb-Mordenite catalyst. All values are in wt %
unless noted otherwise. This data is shown graphically in FIGS.
1-3. Table 3 gives comparative data from the disproportionation of
toluene to benzene and xylene using a commercial 1% Ni/Mordenite
catalyst (Zeolyst CP-751). The comparative data is graphed in FIG.
5.
TABLE-US-00002 TABLE 1 Toluene Conversion, Temp, Aromatic
Selectivity and Liquid Nonaromatics over Nb/Mordenite Catalyst
Toluene Liquid conver- Temp Xylene Benzene Heavies non-aromatic Day
sion .degree. F. Selectivity Selectivity Selectivity Selectivity 1
25.6 660 54.1 38.1 7.1 0.50 2 30.1 674 53.8 39.2 6.6 0.34 3 38.4
697 51.7 40.3 7.6 0.30 8 27.6 658 53.2 40.3 5.9 0.37 9 40.3 716
50.7 40.1 8.0 0.31 10 44.0 733 49.2 40.9 8.7 0.35 13 47.7 757 48.1
40.4 9.9 0.38 15 49.6 761 50.0 36.7 11.6 0.32 16 47.5 757 48.6 39.8
10.0 0.36 17 48.1 760 48.8 39.0 10.3 0.35 20 47.5 760 47.8 40.9 9.5
0.40 21 47.7 762 48.4 39.9 10.0 0.37 22 47.8 762 49.3 38.1 10.5
0.35 23 47.7 762 48.7 39.6 9.9 0.37 24 47.6 762 47.8 40.9 9.5 0.40
27 47.7 764 49.5 38.2 10.7 0.36 28 47.7 764 50.3 36.9 11.0 0.34 29
47.1 764 50.5 37.2 10.9 0.34 30 47.8 766 50.7 36.5 11.3 0.31
TABLE-US-00003 TABLE 2 C5+ Nonaromatics in Liquid Effluent over
Nb/Mordenite Catalyst Day Isopentane Pentane Cyclopentane MCP 1
0.0048 0.0000 0.0043 0.0036 2 0.0028 0.0000 0.0000 0.0000 3 0.0040
0.0000 0.0000 0.0028 8 0.0035 0.0000 0.0000 0.0025 9 0.0074 0.0022
0.0060 0.0040 10 0.0046 0.0016 0.0039 0.0027 13 0.0083 0.0028
0.0061 0.0039 15 0.0071 0.0000 0.0055 0.0035 16 0.0047 0.0017
0.0034 0.0000 17 0.0082 0.0000 0.0060 0.0036 20 0.0075 0.0027
0.0055 0.0034 21 0.0076 0.0028 0.0055 0.0033 22 0.0081 0.0028
0.0057 0.0000 23 0.0000 0.0027 0.0000 0.0033 24 0.0065 0.0024
0.0000 0.0000 27 0.0055 0.0018 0.0036 0.0000 28 0.0082 0.0028
0.0056 0.0000 29 0.0056 0.0020 0.0041 0.0025 30 0.0032 0.0000
0.0000 0.0000
[0037] Comparative data for disproportionation of toluene to
benzene and xylene using a commercial Ni/Mordenite catalyst,
Zeolyst CP 751.
TABLE-US-00004 TABLE 3 Toluene Disproportionation Data using
Ni/Mordenite with Sulfiding Toluene Liquid conver- Temp Xylene
Benzene Heavies non-aromatic Day sion .degree. F. Selectivity
Selectivity Selectivity Selectivity 1 43.5 653 47.6 42.4 8.6 0.77 2
42.7 663 47.7 42.4 8.5 0.63 3 47.4 682 47.6 40.5 10.4 0.49 6 48.5
692 47.7 40.2 10.6 0.53 7 47.3 683 48.5 40.6 9.6 0.39 8 48.1 686
48.9 39.7 10.1 0.38 9 48.1 686 47.9 40.6 9.6 0.39 10 48.1 686 48.2
40.3 9.7 0.37 13 46.5 684 50.2 38.5 10.1 0.32 14 45.9 684 49.1 40.2
9.6 0.36 15 48.2 692 48.6 40.0 9.9 0.37 16 47.8 692 49.0 39.7 9.9
0.36 17 48.7 693 49.3 39.1 10.2 0.36 20 48.6 698 47.8 38.1 10.3
0.36 21 49.3 698 48.3 40.4 10.0 0.38 22 47.4 690 49.3 39.4 10.0
0.36 23 47.4 691 49.6 38.8 10.2 0.34 24 47.3 690 49.5 39.2 10.0
0.36 27 46.7 690 49.2 39.8 9.7 0.36 29 48.1 696 49.2 39.1 10.3 0.34
30 47.7 696 48.7 40.2 10.0 0.37 31 48.1 696 49.9 38.1 10.6 0.35 34
47.0 694 50.0 38.5 10.1 0.33 35 47.3 697 48.8 39.4 9.9 0.36
TABLE-US-00005 TABLE 4 C5+ Nonaromatics in Liquid Effluent over
Ni/Mordenite Catalyst. Day Isopentane Pentane Cyclopentane MCP 1
0.0187 0.0052 0.0191 0.0196 2 0.0174 0.0043 0.0153 0.0123 3 0.0061
0.0016 0.0052 0.0043 6 0.0024 0.0000 0.0000 0.0000 7 0.0049 0.0000
0.0000 0.0000 8 0.0029 0.0000 0.0000 0.0000 9 0.0086 0.0026 0.0000
0.0055 10 0.0066 0.0019 0.0056 0.0044 13 0.0065 0.0019 0.0055
0.0045 14 0.0106 0.0028 0.0000 0.0063 15 0.0101 0.0027 0.0074
0.0056 16 0.0083 0.0024 0.0000 0.0051 17 0.0072 0.0022 0.0000
0.0046 20 0.0100 0.0030 0.0000 0.0057 21 0.0109 0.0032 0.0000
0.0061 22 0.0082 0.0000 0.0062 0.0049 23 0.0077 0.0000 0.0061
0.0047 24 0.0094 0.0000 0.0078 0.0059 27 0.0078 0.0000 0.0065
0.0049 29 0.0090 0.0000 0.0075 0.0055 30 0.0100 0.0031 0.0082
0.0060 31 0.0065 0.0020 0.0054 0.0042 34 0.0049 0.0015 0.0000
0.0032 35 0.0101 0.0031 0.0000 0.0059
[0038] Various terms are used herein, to the extent a tem used in
not defined herein, it should be given the broadest definition
persons in the pertinent art have given that term as reflected in
printed publications and issued patents.
[0039] The term "activity" refers to the weight of product produced
per weight of the catalyst used in a process per hour of reaction
at a standard set of conditions (e.g., grams product/gram
catalyst/hr).
[0040] The tem "deactivated catalyst" refers to a catalyst that has
lost enough catalyst activity to no longer be efficient in a
specified process. Such efficiency is determined by individual
process parameters.
[0041] The term "molecular sieve" refers to a material having a
fixed, open-network structure, usually crystalline, that may be
used to separate hydrocarbons or other mixtures by selective
occlusion of one or more of the constituents, or may be used as a
catalyst in a catalytic conversion process.
[0042] The term "zeolite" refers to a molecular sieve containing a
silicate lattice, usually in association with some aluminum, boron,
gallium, iron, and/or titanium, for example. In the following
discussion and throughout this disclosure, the terms molecular
sieve and zeolite will be used more or less interchangeably. One
skilled in the art will recognize that the teachings relating to
zeolites are also applicable to the more general class of materials
called molecular sieves.
[0043] Depending on the context, all references herein to the
"invention" may in some cases refer to certain specific embodiments
only. In other cases it may refer to subject matter recited in one
or more, but not necessarily all, of the claims. While the
foregoing is directed to embodiments, versions and examples of the
present invention, which are included to enable a person of
ordinary skill in the art to make and use the inventions when the
information in this patent is combined with available information
and technology, the inventions are not limited to only these
particular embodiments, versions and examples.
[0044] While the foregoing is directed to embodiments of the
present invention, other and further embodiments of the invention
may be devised without departing from the basic scope thereof and
the scope thereof is determined by the claims that follow.
* * * * *