Hydrocarbon conversion catalyst

A hydrocarbon conversion catalyst useful for hydrocracking hydrocarbons to more valuable products comprises one or more hydrogenation components supported on a base containing (1) a crystalline aluminosilicate zeolite having activity for cracking hydrocarbons and (2) a dispersion of silica-alumina in an alumina matrix.

BACKGROUND OF THE INVENTION 
This invention relates to a hydrocracking process and a catalyst for use 
therein. More particularly, it relates to a hydrocracking catalyst of 
improved activity, selectivity, and stability for producing middle 
distillates from heavy gas oils and the like under hydrocracking 
conditions. 
Petroleum refiners often produce desirable products such as turbine fuel, 
diesel fuel, and other middle distillate products by hydrocracking a heavy 
gas oil, i.e., a hydrocarbon fraction having a boiling point range between 
about 700.degree. F. and 1050.degree. F. Hydrocracking is accomplished by 
contacting the heavy gas oil at an elevated temperature and pressure in 
the presence of hydrogen and a suitable hydrocracking catalyst so as to 
yield a middle distillate fraction boiling in the 300.degree.-700.degree. 
F. range and containing the desired turbine and diesel fuels. 
The three main catalytic properties by which the performance of a 
hydrocracking catalyst for producing middle distillate products is 
evaluated are activity, selectivity, and stability. Activity may be 
determined by comparing the temperature at which various catalysts must be 
utilized under otherwise constant hydrocracking conditions with the same 
feedstock so as to produce a given percentage (usually 60%) of products 
boiling below 700.degree. F. The lower the activity temperature for a 
given catalyst, the more active such a catalyst is in relation to a 
catalyst of higher activity temperature. Selectivity of hydrocracking 
catalysts may be determined during the foregoing described activity test 
and is measured as that percentage fraction of the 700.degree. F.-minus 
product boiling in the range of middle distillate or midbarrel products, 
i.e., 300.degree.-700.degree. F. Stability is a measure of how well a 
catalyst maintains its activity over an extended time period when treating 
a given hydrocarbon feedstock under the conditions of the activity test. 
Stability is generally measured in terms of the change in temperature 
required per day to maintain a 60% or other given conversion. 
As could be expected, the aim of the art is to provide a catalyst having at 
once the highest possible activity, selectivity, and stability. Catalysts 
usually utilized for hydrocracking comprise a Group VIII metal component, 
most often cobalt or nickel sulfides, in combination with a Group VIB 
metal component, most often molybdenum or tungsten sulfides, supported on 
a refractory oxide. For given proportions of Group VIII and Group VIB 
metal components, the activity, selectivity, and stability of a catalyst 
change dramatically with different supports. Support materials comprising 
crystalline aluminosilicate zeolites, such as Zeolite Y in the hydrogen 
form, generally provide high activity but low selectivity, whereas support 
materials consisting essentially of refractory oxides, such as alumina, 
magnesia, and silica-alumina, generally have relatively poor activity but 
high selectivity. 
The object of the present invention, therefore, is to provide a 
hydrocracking catalyst having superior overall catalytic properties for 
hydrocracking hydrocarbons. More specifically, it is an object of the 
invention to provide a catalyst having superior overall activity, 
selectivity, and stability for hydrocracking in comparison to prior art 
catalysts. It is a further object to provide a hydrocracking process for 
converting gas oils and the like to middle distillate products. It is a 
further object to provide a support or carrier material useful with a 
hydrogenation component as a catalyst for hydrogenating and/or 
hydrocracking hydrocarbons. These and other objects and advantages will 
become more apparent in light of the following description of the 
invention. 
SUMMARY OF THE INVENTION 
The present invention is an improvement of the catalyst described in U.S. 
Pat. No. 4,097,365, herein incorporated by reference. The catalyst 
described in this reference is a midbarrel hydrocracking catalyst 
comprising hydrogenation components on a refractory oxide support 
comprising silica-alumina dispersed in a matrix of alumina. The present 
invention improves this catalyst by including in the support a crystalline 
aluminosilicate zeolite having cracking activity, such as hydrogen Y 
zeolite or a rare earth-exchange Y zeolite. In addition to having 
excellent activity for hydrodenitrogenation and hydrodesulfurization, the 
catalyst of the invention has been found to have superior overall 
properties of activity, selectivity, and stability for hydrocracking in 
comparison to the catalyst described in U.S. Pat. No. 4,097,365. In the 
usual instance, the catalyst of the invention is more active, more stable, 
and more selective than comparison catalysts having supports consisting 
essentially of either a dispersion of silica-alumina in an alumina matrix 
or a zeolite plus a refractory oxide other than a dispersion of 
silica-alumina in an alumina matrix. 
In its broadest embodiment, the present invention provides a catalyst 
support comprising in intimate admixture (1) a crystalline aluminosilicate 
zeolite having cracking activity and (2) a dispersion of silica-alumina in 
an alumina matrix. Although the support is most preferred when used in 
conjunction with a hydrogenation component, it may itself be utilized in 
the absence of a hydrogenation component as a catalyst for converting 
hydrocarbons to more valuable products by acid catalyzed reactions, such 
as catalytic cracking, isomerization of n-paraffins to isoparaffins, 
isomerization of alkyl aromatics, alkylation, and transalkylation of alkyl 
aromatics. 
DETAILED DESCRIPTION OF THE INVENTION 
The catalyst of the invention is an intimate composite of one or more 
hydrogenation components, a crystalline aluminosilicate zeolite having 
catalytic activity for cracking hydrocarbons, and a dispersion of 
silica-alumina in a matrix consisting essentially of alumina. The 
hydrogenation components useful in the invention are the metals, oxides, 
and sulfides of uranium, the Group VIII elements, and the Group VIB 
elements. The most suitable hydrogenation components are selected from the 
group consisting of the metals, oxides, and sulfides of platinum, 
palladium, cobalt, nickel, tuungsten, and molybdenum. The preferred 
catalyst contains at least one Group VIII metal component, and at least 
one Group VIB metal component, with the most preferred combination being a 
nickel and/or cobalt component with a molybdenum and/or tungsten 
component. 
The hydrogenation component or components are intimately composited on a 
base or support comprising a mixture of one or more crystalline 
aluminosilicate zeolites having cracking activity and a heterogeneous 
dispersion of finely divided silica-alumina in a matrix of alumina. The 
suitable zeolites for use herein include crystalline aluminosilicate 
molecular sieves having catalytic activity for cracking hydrocarbons. Many 
naturally-occurring and synthetic crystalline aluminosilicate zeolites 
known in the art are useful in the invention, including, for example, 
faujasite, mordenite, erionite, Zeolite Y, Zeolite X, Zeolite L, Zeolite 
Omega, Zeolite ZSM-4, and their modifications. These and other such 
zeolitic molecular sieves are known to have activity for cracking 
hydrocarbons when a substantial proportion of the ion exchange sites are 
occupied with hydrogen ions or multivalent metal-containing cations, 
particularly rare earth cations. Normally, crystalline aluminosilicate 
zeolites are obtained in the alkali metal form and as such are largely 
inactive for catalytically cracking hydrocarbons. To produce a zeolite 
having cracking activity, the alkali metals are usually replaced with 
multivalent metal-containing cations, hydrogen ions, or hydrogen ion 
precursors (e.g. ammonium ion). This replacement of cations is generally 
accomplished by ion exchange, a method well-known in the art wherein the 
zeolite in the sodium or other alkali metal form is contacted with an 
aqueous solution containing hydrogen ions, ammonium ions, rare earth ions, 
or other suitable cations. Replacing even a portion of the sodium ions 
produces a zeolite having some cracking activity, but reducing the alkali 
metal content to less than 5 wt.%, preferably to less than 1 wt.%, and 
most preferably to less than about 0.5 wt.% (calculated as the alkali 
metal oxides), results in a material having substantial cracking activity, 
with the activity varying according to the zeolite and the amount of 
alkali metals removed. 
In addition to the zeolites referred to above, many other crystalline 
aluminosilicate zeolites in their non-alkali metal forms may be utilized 
in the catalyst support of the invention. Preferred zeolites contain at 
least 50% of their pore volume in pores of diameter greater than 8 
Angstroms, with Zeolite Y (and its modifications) in the hydrogen form or 
in other forms imparting cracking activity to the zeolite being preferred 
zeolites for use in the invention. Also preferred are zeolites that have 
been ion-exchanged with ammonium ions and then steam stabilized in 
accordance with the teachings of U.S. Pat. No. 3,929,672, herein 
incorporated by reference. The most highly preferred zeolite is a material 
known as LZ-10, a zeolitic molecular sieve available from Union Carbide, 
Linde Division. Although LZ-10 is a proprietary material, it is known that 
LZ-10 is a modified Y zeolite having a silica to alumina ratio between 
about 3.5 and 4.0, a surface area between about 500 and 700 m.sup.2 /gm, a 
unit cell size between about 24.25 and 24.35 Angstroms, water absorption 
capacity less than about 8% by weight of the zeolite (at 4.6 mm partial 
pressure of water vapor and 25.degree. C.), and an ion-exchange capacity 
less than 20% of that of a sodium Y zeolite of comparable silica to 
alumina ratio. When used as a hydrocracking catalyst, LZ-10 is highly 
active and selective for midbarrel hydrocracking, especially when 
composited with alumina and suitable hydrogenation components. 
The support material utilized in the invention usually comprises between 2 
and about 80% by weight, preferably between about 10 and about 70% by 
weight, of a crystalline aluminosilicate zeolite such as LZ-10. The 
support also comprises a substantial proportion of a heterogeneous 
dispersion of finely divided silica-alumina in an alumina matrix. Usually, 
the dispersion comprises at least 15% by weight of the support, with the 
preferred and most preferred proportions being in the respective ranges of 
30 to 98% and 30 to 90% by weight of the support. 
One convenient method of preparing the catalyst support herein is to comull 
an alumina hydrogel with a silica-alumina cogel in hydrous or dry form. 
The cogel is preferably homogeneous and may be prepared in a manner such 
as that described in U.S. Pat. No. 3,210,294. Alternatively, the alumina 
hydrogel may by comulled with a "graft copolymer" of silica and alumina 
that has been prepared, for example, by first impregnating a silica 
hydrogel with an alumina salt and then precipitating alumina gel in the 
pores of the silica hydrogel by contact with ammonium hydroxide. In the 
usual case, the cogel or copolymer (either of which usually comprses 
silica in a proportion by dry weight of 20 to 96%, preferably 50 to 90%) 
is mulled with the alumina hydrogel such that the cogel or copolymer 
comprises 5 to 75% by weight, preferably 20 to 65% by weight, of the 
mixture. The overall silica content of the resulting dispersion on a dry 
basis is usually between 1 and 75 wt.%, preferably between 5 and 45 wt.%. 
The mulled mixture of alumina gel with either a silica-alumina cogel or a 
silica and alumina "graft copolymer" may be utilized in the gel form or 
may be dried and/or calcined prior to combination with the zeolite. In the 
preferred method of preparation, the cogel or copolymer is spray dried and 
then crushed to a powdered form, following which the powder is mulled with 
a zeolite powder containing hydrogen ions, hydrogen ion precursors, or 
multivalent metal-containing cations, the amounts of cogel or copolymer 
mulled with said zeolite being such that the support will ultimately 
contain zeolite and dispersion in the proportions set forth hereinbefore. 
If desired, a binder may also be incorporated into the mulling mixture, as 
also may one or more active metal hydrogenation components in forms such 
as ammonium heptamolybdate, nickel nitrate or chloride, ammonium 
metatungstate, cobalt nitrate or chloride, etc. After mulling, the mixture 
is extruded through a die having suitable openings therein, such as 
circular openings of diameters between about 1/32 and 1/8 inch. 
Preferably, however, the die has openings therein in the shape of 
three-leaf clovers so as to produce an extrudate material similar to that 
shown in FIGS. 8 and 8A of U.S. Pat. No. 4,028,227. The extruded material 
is cut into lengths of about 1/32 to 3/4 inch, preferably 1/4 to 1/2 inch, 
dried, and calcined at an elevated temperature. 
If desired, hydrogenation components may be composited with the support by 
impregnation; tht is, rather than comulling the hydrogenation components 
with the support materials, the zeolite and dispersion are mulled, 
extruded, cut into appropriate lengths, and calcined. The resulting 
particles are then contacted with one or more solutions containing the 
desired hydrogenation components in dissolved form, and the composite 
particles thus prepared are dried and calcined to produce finished 
catalyst particles. 
Usually, the finished catalyst contains at least about 0.5 wt.% of 
hydrogenation components, calculated as the metals. In the usual instance, 
wherein a Group VIII metal and a Group VIB metal component are utilized in 
combination, the finished catalyst contains between about 5% and 35%, 
preferably between about 10 and 30% by weight, calculated as the 
respective trioxides, of the Group VIB metal components and between about 
2% and 15%, preferably between 3 and 10% by weight, calculated as the 
respective monoxides, of the Group VIII metal components. 
If desired, a phosphorous component may also be incorporated in the 
catalyst by either comulling the support materials with phosphoric acid or 
including phosphoric acid in the impregnating solution. Usual and 
preferred proportions of phosphorus in the catalyst fall in the ranges of 
1 to 10 wt.% and 3 to 8 wt.%, calculated as P.sub.2 O.sub.5. 
The hydrogenation components, which will largely be present in their oxide 
forms after calcination in air, may be converted to their sulfide forms, 
if desired, by contact at elevated temperatures with a reducing atmosphere 
comprising hydrogen sulfide. More conveniently, the catalyst is sulfided 
in situ, i.e., by contact with a sulfur-containing feedstock to be 
catalytically converted to more valuable hydrocarbons in such processes as 
hydrocracking, hydrotreating, etc. 
The foregoing described catalysts are especially useful for hydrogenation 
reactions, such as hydrodenitrogenating and hydrodesulfurizing 
hydrocarbons, but are particularly useful with respect to hydrocracking to 
convert a hydrocarbon feedstock to a more valuable product of lower 
average boiling point and lower average molecular weight. The feedstocks 
that may be treated herein by hydrogenation include all mineral oils and 
synthetic oils (e.g., shale oil, tar sand products, etc.) and fractions 
thereof. Typical feedstocks include straight run gas oils, vacuum gas 
oils, deasphalted vacuum and atomspheric residua, coker distillates, and 
catcracker distillates, Preferred hydrocracking feedstocks include gas 
oils and other hydrocarbon fractions having at least 50% by weight of 
their components boiling above 700.degree. F. Suitable and preferred 
conditions for hydrocracking gas oil feedstocks, as well as for 
hydrodenitrogenating and/or hydrodesulfurizing such feedstocks, are: 
TABLE I 
______________________________________ 
Suitable 
Preferred 
______________________________________ 
Temperature, .degree.F. 
500-850 600-800 
Pressure, psig 750-3500 1000-3000 
LHSV 0.3-5.0 0.5-3.0 
H.sub.2 /Oil, MSCF/bbl 
1-10 2-8 
______________________________________

As will be shown by the following Examples, which are provided for 
illustrative purposes and are not to be construed as limiting the scope of 
the invention as defined by the claims, the present catalysts have been 
found to possess superior overall catalytic properties with respect to 
activity, selectivity, and stability when conversion of gas oils to 
midbarrel products by hydrocracking is desired. In many instances, the 
catalysts of the invention have been found to be superior in each of the 
three main performance categories of activity, selectivity, and stability. 
EXAMPLE I 
An experiment was performed to compare the activity, selectivity, and 
stability of catalysts of the invention containing LZ-10 and a dispersion 
of silica alumina in a gamma alumina matrix versus catalysts having 
supports consisting essentially of LZ-10 and gamma alumina. Following are 
the preparation procedures used for Catalyst Nos. 1 through 4, with 
Catalyst Nos. 2 and 3 being representative of the invention and Catalyst 
Nos. 1 and 4 being the comparison catalysts. 
CATALYST NO. 1 
A mixture of 10% by weight powdered LZ-10 that had been ion-exchanged with 
ammonium nitrate to reduce the sodium content to about 0.1% by weight 
sodium (as Na.sub.2 O) and 90% by weight gamma alumina was extruded 
through a die having openings therein in a three-leaf clover shape, each 
leaf being defined by about a 270.degree. arc of a circle having a 
diameter between about 0.02 and 0.04 inches. The extruded material was cut 
into 1/4-1/2 inch lengths and calcined at 900.degree. F. in air to convert 
the LZ-10 material to the hydrogen form. The calcined particles (300 gm) 
were then impregnated with 330 ml of an aqueous solution containing 67 gm 
of nickel nitrate (Ni(NO.sub.3).sub.2.6H.sub.2 O) and 108 gm of ammonium 
metatungstate (91% WO.sub.3 by weight). After removing excess liquid, the 
catalyst was dried at 230.degree. F. and calcined at 900.degree. F. in 
flowing air. The final catalyst contained 4.4 wt.% nickel components 
(calculated as NiO) and 25.0 wt.% tungsten components (calculated as 
WO.sub.3). 
CATALYST NO. 2 
The procedure described for Catalyst No. 1 was repeated except that in 
place of alumina a dispersion of spray dried, powdered silica-alumina in 
alumina prepared in a manner similar to that of Example 3 of U.S. Pat. No. 
4,097,365 was used. The dispersion was prepared by mixing 44 parts by dry 
weight of a 75/25 silica-alumina graft copolymer and 56 parts by weight of 
hydrous alumina gel. In the final catalyst, the support consisted 
essentially of 10% LZ-10 in the hydrogen form and 90% dispersion of silica 
alumina in an alumina matrix, the dispersion consisting overall of 33% by 
weight silica and 67% by weight alumina. The resulting catalyst contained 
4.1% by weight nickel components (as NiO) and 24.2% by weight tungsten 
components (as WO.sub.3). 
CATALYST NO. 3 
This catalyst was prepared in the same manner as Catalyst No. 2 except that 
the proportions of LZ-10 and dispersion admixed to prepare the support 
were adjusted so that in the final catalyst the proportion of LZ-10 in the 
support was 5% by weight and that of the dispersion, 95% by weight. The 
final catalyst contained 4.1% by weight nickel components (as NiO) and 
23.6% by weight tungsten components (as WO.sub.3) on a support of 5% LZ-10 
and 95% dispersion. 
CATALYST NO. 4 
This catalyst was prepared in the same manner as Catalyst No. 1 except that 
the proportions of LZ-10 and alumina admixed during preparation were such 
that in the final catalyst the proportion of LZ-10 in the support was 20% 
by weight and that of the gamma alumina, 80% by weight. The final catalyst 
contained 4.1% by weight nickel components (as NiO) and 24.4% by weight 
tungsten components (as WO.sub.3) on a support of 20% LZ-10 and 80% gamma 
alumina. 
Each of the foregoing catalysts was then activity tested according to the 
following method. A preheated light Arabian vacuum gas oil having the 
chemical and physical properties shown in Table II was passed on a 
once-through basis through an isothermal reactor containing 140 ml of 
catalyst particles uniformly mixed with 160 ml of 10 to 20 mesh quartz. 
Operating conditions were as follows: 1.0 LHSV, 2000 psig, a once-through 
hydrogen flow of 10,000 scf/bbl, and a run length of approximately 10 
days. The temperature of the reactor was adjusted to provide a 60 volume 
percent conversion to products boiling at 700.degree. F. or less. The 
results of the activity testing are reported in Table III. 
TABLE II 
______________________________________ 
PROPERTIES OF LIGHT ARABIAN VACUUM GAS OIL 
______________________________________ 
Gravity, .degree.API 
22.3 Pour Point, .degree.F. 
100.0 
Distillation, .degree.F., D-1160 
Sulfur, XRF, wt. % 2.37 
IBP/5 693/760 Nitrogen, KJEL, wt. % 
0.079 
Hydrogen, wt. % 12.20 
10/20 777/799 Chlorine, ppm &lt;1.0 
30/40 815/832 Carbon Residue, D-189, wt. % 
0.14 
50/60 850/870 Viscosity, SSU at 100.degree. F. 
319.0 
70/80 894/920 Viscosity, SSU at 210.degree. F. 
51.1 
Specific Gravity 0.9200 
90/95 958/979 
EP/% Rec. 
1053/99.0 
______________________________________ 
TABLE III 
______________________________________ 
Activity.sup.1 
Selectivity.sup.2 
Reactor Vol. % 
Catalyst Temp. to Conv. to 
Description Provide 300.degree.-700.degree. F. 
Stability.sup.3 
No. of Support 60% Conv. Product .degree.F./day 
______________________________________ 
1 10% LZ-10 and 772.degree. F. 
83.5 0.68 
90% Gamma 
Alumina 
2 10% LZ-10 and 750.degree. F. 
83.5 -0.72 
90% SiO.sub.2 --Al.sub.2 O.sub.3 in 
Gamma Alumina 
Matrix 
3 5% LZ-10 and 776.degree. F. 
87.4 0.09 
95% SiO.sub.2 --Al.sub.2 O.sub.3 in 
Gamma Alumina 
Matrix 
4 20% LZ-10 and 750.degree. F. 
75.2 0.39 
80% Gamma 
Alumina 
______________________________________ 
.sup.1 Activity data are those obtained on tenth day of run. 
.sup.2 Selectivity data are an average of data obtained over 10 days and 
are calculated as the volume of 300.degree.-700.degree. F. components to 
the total volume of components boiling at or below 700.degree. F. 
.sup.3 Stability data were calculated using the reactor temperature 
required to produce a 60% conversion on the 2nd and 10th days of the run. 
The data in Table III reveal that in comparison to the two hydrocracking 
catalysts having supports consisting of LZ-10 and gamma alumina, the 
catalysts of the invention are far superior in terms of overall activity, 
selectivity, and stability. A comparison of Catalyst Nos. 1 and 2 shows 
that, for the same percentage of LZ-10 in the support, Catalyst No. 2 
prepared in accordance with the invention was 22.degree. F. more active 
and much more stable than Catalyst No. 1. In addition, Catalyst No. 2 
proved to be as selective for producing midbarrel products as Catalyst No. 
1. Comparing Catalysts Nos. 2 and 4 and Catalysts 3 and 1 shows that the 
catalysts of the invention are as active, but substantially more stable 
and selective, than their LZ-10-alumina comparisons containing twice as 
much zeolite. 
EXAMPLE II 
A second experiment was performed under the run conditions of Example I to 
demonstrate the improved performance attainable with the catalyst of the 
invention in comparison to the catalysts described in U.S. Pat. No. 
4,097,365. The catalyst utilized in the experiment were prepared as 
follows: 
CATALYST NO. 5 
A catalyst support was prepared in the same manner as described in Example 
3 of U.S. Pat. No. 4,097,365 except that 54 parts of the silica-alumina 
graft copolymer were mixed with 46 parts of the hydrous alumina gel. The 
support (in the size and shape as Catalyst No. 1) was calcined and 
impregnated with a nickel nitrate-ammonium metatungstate solution as in 
the preparation of Catalyst No. 1, and then dried and calcined in the same 
way. The final catalyst contained 4.1 wt.% nickel components (as NiO) and 
24.4 wt.% tungsten components (as WO.sub.3) supported on a base consisting 
essentially of a dispersion of 75/25 silica-alumina in an alumina matrix, 
the base having an overall silica content of 40% and an overall alumina 
content of 60%. 
CATALYST NO. 6 
This catalyst was prepared in the same manner as Catalyst No. 5 except that 
LZ-10 in the ammonium form and peptized alumina binder were incorporated 
into the support such that, after calcination, LZ-10 in the hydrogen form 
comprised 10 percent by weight of the support and the binder comprised 20 
percent by weight of the support. 
The results obtained from testing Catalysts Nos. 5 and 6 for activity, 
selectivity, and stability are reported in Table IV. 
TABLE IV 
______________________________________ 
Activity.sup.1 
Selectivity.sup.2 
Reactor Vol. % 
Catalyst Temp. to Conv. to 
Description Provide 300.degree.-700.degree. F. 
Stability.sup.3 
No. of Support 60% Conv. Product .degree.F./day 
______________________________________ 
5 Dispersion of 773.degree. F. 
88.7 0.23 
SiO.sub.2 /Al.sub.2 O.sub.3 in 
Gamma Alumina 
Matrix 
6 10% LZ-10 and 753.degree. F. 
87.4 0.05 
90% Dispersion 
of SiO.sub.2 --Al.sub.2 O.sub.3 in 
Gamma Alumina 
______________________________________ 
.sup.1 Activity data are those obtained on tenth day of run. 
.sup.2 Selectivity data are an average of data obtained over 10 days and 
are calculated as the volume of 300.degree.-700.degree. F. components to 
the total volume of components boiling at or below 700.degree. F. 
.sup.3 Stability data were calculated using the reactor temperatures 
required to produce a 60% conversion on the 2nd and 10th days of the run. 
As is self-evident from the data in Table IV, the catalyst of the 
invention, Catalyst No. 6, proved far superior to a catalyst similar to 
that described in Example 3 of U.S. Pat. No. 4,097,365. Catalyst No. 6 
provides substantially more activity and stability than Catalyst No. 5 
with no significant loss in selectivity. 
EXAMPLE III 
A third comparison experiment was run to determine the activity of two 
catalysts of the invention comprising nickel and molybdenum components on 
supports comprising LZ-10 and a dispersion of silica-alumina in a gamma 
alumina matrix versus a catalyst comprising nickel and molybdenum 
components on a support comprising LZ-10 and alumina but containing no 
dispersion. The catalysts were prepared as follows: 
CATALYST NO. 7 
Sixty grams of gamma alumina powder were comulled with 120 gm LZ-10 in the 
ammonia form, 20 gm peptized alumina, 75 gm ammonium heptamolybdate 
((NH.sub.4).sub.6 Mo.sub.7 O.sub.24.4H.sub.2 O), and 85 gm nickel nitrate 
hexahydrate. The mulled mixture was extruded through a die similar to that 
used in preparing Catalyst No. 1, cut into 1/4-1/2 inch lengths, and 
calcined in air at 900.degree. F. The resulting catalyst contained 7.7 
wt.% nickel components (as NiO), 21.9 wt.% molybdenum components (as 
MoO.sub.3), about 43 wt.% LZ-10, about 21 wt.% gamma alumina, and the 
remainder (about 7 wt.%) peptized alumina. 
CATALYST NO. 8 
This catalyst was prepared in the same fashion as was Catalyst No. 7 except 
that, in place of the gamma alumina, 60 gm of a powdered dispersion of 
75/25 silica-alumina in a gamma alumina matrix was used. The dispersion 
was prepared by spray drying a mixture comprising 33 parts by weight 
silica-alumina graft copolymer with 67 parts by weight of hydrous alumina 
gel. The final catalyst contained 7.4 wt.% nickel components (as NiO), 
21.5 wt.% molybdenum components (as MoO.sub.3), about 43 wt.% LZ-10, about 
7% of peptized alumina, and about 21% of the dispersion containing 25 wt.% 
silica and 75 wt.% alumina overall. 
CATALYST NO. 9 
This catalyst was prepared in the same manner as Catalyst No. 8 except that 
the dispersion was prepared by mixing 54 parts by weight of 75/25 
silica-alumina graft copolymer with 46 parts by weight of hydrous alumina 
gel. The final catalyst was of the same composition as Catalyst No. 8 
except for the overall silica and alumina contents of the dispersion, 
which were 40% and 60% by weight, respectively. 
The foregoing catalysts were subjected to the 10-day activity tests 
described in Example I, and the results are shown in Table V. As shown, 
the results prove the superiority of the catalysts of the invention (i.e., 
Catalysts Nos. 8 and 9) in all categories. In addition, the data show the 
improvement obtained when the silica contents of the catalysts of the 
invention are increased. 
TABLE V 
______________________________________ 
Activity.sup.1 
Selectivity.sup.2 
Reactor Vol. % 
Catalyst Temp. To Conv. to 
Description Provide 300.degree.-700.degree. F. 
Stability.sup.3 
No. of Support 60% Conv. Product .degree.F./day 
______________________________________ 
7 LZ-10 and 745.degree. F. 
74.8 1.43 
Gamma Alumina 
8 LZ-10 and 743.degree. F. 
79.4 0.17 
SiO.sub.2 --Al.sub.2 O.sub.3 in 
Gamma Alumina 
Matrix 
(25% SiO.sub.2 Overall) 
9 LZ-10 and 733.degree. F. 
79.5 0.88 
SiO.sub.2 --Al.sub.2 O.sub.3 in 
Gamma Alumina 
Matrix 
(40% SiO.sub.2 O.sub.2 Overall) 
______________________________________ 
.sup.1 Activity data are those obtained on tenth day of run. 
.sup.2 Selectivity data are an average of data obtained over 10 days and 
are calculated as the volume of 300.degree.-700.degree. F. components to 
the total volume of components boiling at or below 700.degree. F. 
.sup.3 Stability data were calculated using the reactor temperatures 
required to produce a 60% conversion on the 2nd and 10th days of the run. 
EXAMPLE IV 
A fourth experiment was conducted to compare the catalytic properties of a 
catalyst of the invention incorporating a stabilized Y zeolite with the 
catalytic properties of a similar catalyst containing stabilized Y zeolite 
but containing no dispersion of silica-alumina in an alumina matrix. The 
two catalysts were prepared as follows: 
CATALYST NO. 10 
A mixture of 40 gm stabilized Y zeolite (prepared in accordance with the 
method described in U.S. Pat. No. 3,929,672 for Catalyst A in Example 16 
but without adding palladium), 40 gm peptized alumina binder, and 120 gm 
of dispersion of the kind described for Catalyst No. 9 were comulled with 
a 380 ml aqueous solution containing 78 gm ammonium heptamolybdate 
tetrahydrate, 29.1 gm phosphoric acid (85% H.sub.3 PO.sub.4), and 85 gm 
nickel nitrate hexahydrate. The resulting material was extruded in the 
same manner as Catalyst No. 1, cut into particles of 1/4-1/2 inch length, 
and calcined in air at 900.degree. F. The final catalyst contained about 6 
wt.% nickel components (as NiO), about 19 wt.% molybdenum components (as 
MoO.sub.3), and about 6 wt.% phosphorus components (as P.sub.2 O.sub.5). 
CATALYST NO. 11 
This catalyst was prepared in a manner similar to that of Catalyst No. 10 
with the major difference being (1) that the comulled mixture was extruded 
through a die having circular openings therein of about 1/16 inch diameter 
and (2) the comulled mixture contained 120 gm of powdered gamma alumina 
instead of the dispersion. The resulting catalyst had the same percentage 
composition of nickel, molybdenum, and phosphorus components as Catalyst 
No. 10. 
The foregoing catalysts were then tested in a manner similar to that 
described in Example I except that Catalyst No. 10 was run for 13.6 days 
and Catalyst No. 11 for 8 days. The data obtained are presented in Table 
VI. 
TABLE VI 
______________________________________ 
Activity.sup.1 
Selectivity.sup.2 
Reactor Vol. % 
Catalyst Temp. To Conv. To 
Description Provide 300.degree.-700.degree. F. 
Stability.sup.3 
No. of Support 60% Conv. Product .degree.F./Day 
______________________________________ 
10 Stabilized Y plus 
773.degree. F. 
70.0 1.1 (days 
SiO.sub.2 --Al.sub.2 O.sub.3 in 3.2 to 10) 
Gamma Alumina 0 (days 10.9 
Matrix to 13.6) 
11 Stabilized Y plus 
739.degree. F. 
73.0 0.58 (days 
Gamma Alumina 2.8 to 8.1) 
______________________________________ 
.sup.1 Activity as reported for Catalyst No. 10 is a corrected value 
obtained from data determined for the 10th day of the run, and the 
activity data reported for Catalyst No. 11 is extrapolated from data 
derived on the eighth day of the run. 
.sup.2 Selectivity data are the average of data obtained during first 10 
days with Catalyst No. 10 and the 8 days of run with Catalyst No. 11. 
.sup.3 Stability data were calculated using the reactor temperatures 
required to produce a 60% conversion on the days specified in the Table. 
The results in Table VI again show the overall superiority of the catalyst 
of the invention (Catalyst No. 10) with respect to activity, selectivity, 
and stability. The 6.degree. F. differential in activity between the 
catalyst of the invention and the comparison catalyst represents about a 
20% improvement in activity. Especially significant is the fact that after 
10.9 days, Catalyst No. 10 showed no signs of deactivation, and thus the 
high activity indicated by the 733.degree. F. result could be expected to 
be maintained. 
EXAMPLE V 
Catalyst No. 12 was prepared in the same manner as Catalyst No. 9 except 
that LZ-20 rather than LZ-10 was utilized. (LZ-20 is a crystalline 
aluminosilicate zeolite, available from Union Carbide, Linde Division, 
having a unit cell size, a water sorption capacity, a surface area, and an 
ion exchange capacity somewhat higher than that of LZ-10). The catalyst 
was tested in the same manner as described in Example I except that the 
run length was 8.5 days rather than 10 days. The results of the experiment 
were as follows: Activity: 733.degree. F. (the operating temperature on 
the last day of run), Selectivity: 67.0% (as the average percentage 
conversion to middle distillates during the run), and Stability: 
1.94.degree. F./day as calculated between 2.1 days and the end of run and 
1.86.degree. F./day between 5.3 days and end of the run. A comparison of 
these data with those of Catalyst No. 9 in Example III indicate that 
better results are obtained with LZ-10 in the catalyst support of the 
invention than with LZ-20. 
EXAMPLE VI 
Catalyst No. 13 was prepared by mulling a mixture consisting essentially of 
140 gm of a dispersion of silica-alumina in an alumina matrix as was used 
to prepare Catalyst No. 5, 20 gm LZ-10 in ammonia form (i.e., as in 
Example I), and 40 gm peptized alumina with 380 ml of an aqueous solution 
containing 78 gm ammonium heptamolybdate tetrahydrate, 29.1 gm phosphoric 
acid (85% H.sub.3 PO.sub.4), and 85 gm nickel nitrate hexahydrate. The 
mulled mixture was wet sufficiently to form a paste and extruded through a 
die similar to that described in Example I. The extrudate was cut into 
1/4-178 inch particles in length, dried, and calcined at 900.degree. F. 
The finished catalyst contained 7.6 wt.% nickel components (as NiO), 21.2 
wt.% molybdenum components (as MoO.sub.3), and 7.1 wt.% phosphorus 
components (as P.sub.2 O.sub.5). 
The foregoing catalyst was tested for its catalytic properties in the same 
manner as described in Example I, and the results were as follows: 
Activity: 750.degree. F. on the tenth day of run, Selectivity: 85.6 as the 
average over the ten days of operation, and Stability: 0.85.degree. F./day 
from days 2 through 10 and 0.11.degree. F./day from days 5.8 through 10. 
These results indicate the high activity, selectivity, and stability of 
this embodiment of the catalyst of the invention. 
EXAMPLE VII 
During the runs performed on Catalyst No. 6 in Example II and Catalyst No. 
10 in Example IV, samples of the product oils were obtained and analyzed 
for sulfur content by X-ray fluorescence analysis and nitrogen content by 
coulometric analysis. As shown by the data in Table II, the sulfur and 
nitrogen contents of the feedstock were 2.37 wt.% and 0.079 wt.%, 
respectively. In Table VII are reported the results of the analyses 
performed on the samples of product oil obtained in the experiments 
described in Examples II and IV. The data in Table VII indicate that 
Catalysts Nos. 6 and 10 had substantial activity for hydrodenitrogenation 
and hydrodesulfurization. 
TABLE VII 
______________________________________ 
Days into Sulfur in 
Temp. Run When Product, 
Nitrogen in 
Catalyst 
.degree.F. 
Sample Taken 
ppmw Product, ppmw 
______________________________________ 
No. 6 750 10 6 -- 
No. 10 730 10 93 2.2 
No. 10 734 13 62 1.3 
______________________________________ 
EXAMPLE VIII 
Zeolite LZ-10 is believed to be prepared by high temperature, steam 
calcining the hydrothermally stable and ammonia-stable Zeolite Y 
compositions described in U.S. Pat. No. 3,929,672, herein incorporated by 
reference. One specific method by which LZ-10 may be prepared is as 
follows: 
A sample of air-dried ammonium exchanged Zeolite Y having a composition 
exclusive of water of hydration: 
EQU 0.156 Na.sub.2 O:0.849(NH.sub.4).sub.2 O:Al.sub.2 O.sub.3 :5.13 SiO.sub.2 
is tableted into 1/2 inch diameter slugs and charged to a Vycor tube 
provided with external heating means and having a 24 inch length and a 2.5 
inch diameter. The temperature of the charge is first raised to 
600.degree. C. in about 25 minutes and then held at this temperature for 
one hour. During this 1.25 hour period, a pure steam atmosphere at 14.7 
psia generated from demineralized water is passed upwardly through the 
charge at a rate of 0.1 to 0.5 lbs/hr. Ammonia gas generated during the 
heating deammoniation of the zeolite is passed from the system 
continuously. At the termination of the heating period, the steam flow is 
stopped and the temperature of the charge is lowered to ambient room 
temperature over a period of five minutes. The charge is removed from the 
Vycor tube, and the sodium cation content of the steamed material is 
reduced to about 0.25 weight percent (as Na.sub.2 O) by ion exchange using 
an aqueous solution of 30 weight percent ammonium chloride at reflux. 
The low sodium material thus prepared is recharged to the Vycor tube and 
again steamed, this time using pure steam at 14.7 psia and a temperature 
of 800.degree. C. for 4 hours. The product is then cooled to ambient 
temperature and has the following typical characteristics: Surface 
Area=530 m.sup.2 /gm, Adsorptive Capacity of water at 4.6 mm partial 
pressure and 25.degree. C.=4.6 weight percent, and an ion exchange 
capacity equal to 4% of that of a sodium Y zeolite having a comparable 
SiO.sub.2 :Al.sub.2 O.sub.3 ratio. (The comparable sodium Y zeolite to 
which LZ-10 zeolite is compared in the specification and claims herein is 
a sodium Y zeolite having essentially the same silica to alumina ratio as 
LZ-10 and having a sodium to aluminum content such that the ratio of 
Na.sub.2 O:Al.sub.2 O.sub.3 is equal to 1.0). 
Although the invention has been described in conjunction with several 
comparative examples, may variations, modifications, and alternatives of 
the invention as described will be apparent to those skilled in the art. 
Accordingly, it is intended to embrace within the invention all such 
variations, modifications, and alternatives as fall within the spirit and 
scope of the appended claims.