Note: Descriptions are shown in the official language in which they were submitted.
~ ~3~
HYDROTREATING CAT~LYST AND PROCESS
BACKGROUND OF THE INVE~TION
-
Field of the Invention
This invention relates to hydrotreating catalysts
having a desirable combination of activity and high tem-
perature stability and to processes for preparation and
use thereof.
Description of the Prior Ar_
Ilicreased concern over availability and security of
petroleum crude oil supplies in recent years has focused
considerable attention on producing and upgrading lower
quali~y hydrocarbon feeds, such as synthetic crudes and
heavy petroleum crude oil fractions. Unfortunately, high
concentrations of nitrogen, sulfur, metals and/or high
boiling components, for example, asphaltenes, resins, in
such lower quality feeds render the same poorly suited
for conversion to useful products in conventional petro-
le.um refining operations, such as catalytic cracking and
hydrocracking. For example, in catalytic cracking opera-
tions, nitrogen and metals tend to poison the crackingcatalyst, sulfur leads to increased sulfur oxide
emissions during catalyst regeneration, and high boiling
components lead to formation of coke on the cracking
catalyst which, in turn, can upset the heat balance of
the catalytic cracking unit when the catalyst is regener-
ated. Hydrocracking catalysts also are poisoned by
nitrogen and metals, and in addition, sulfur and coke
promote deactivation ~hereof.
In view of such difficulties, lower quality hydro
carbon feeds often are catalytically hydrotreated to
;3
--2--
obtain materials having greater utility in conventional
downstream refining operations. Catalytic hydrotreating
involves contacting a feed with hydrogen at elevated tern-
perature and pressure in the presence of catalysts having
hydrogenation activity. As a result of such processing,
sulfur and nitrogen in the feed are converted largely to
hydrogen sulfide and ammonia which are easily removed.
Aromatics saturation and, to a lesser extent, cracking of
larger molecules often take place to convert high boiling
feed components to lower boiling components. Metals con-
tent of the feed decreases as a result o deposition of
metals on the surface of the hydrotreating catalyst.
Hydrotreating of low quality hydrocarbon ~eeds often
is conducted under conditions more severe than those used
in conventional hydrotreating of lighter hydrocarbon
feeds in order to achieve suitable levels of nitrogen,
sulfur and/or metals removal and/or conversion of high
boiling components to lower boiling materials. For
example, removal of nitrogen from high nitrogen feeds,
such as whole shale oils or fractions thereof, typically
requires higher temperatures and pressures and lower
space velocities than those used in catalytic hydro-
treating of low nitrogen feeds. Similarly, hydrotreating
heavy petroleum crude oil fractions, such as vacuum or
atmospheric resids and particularly those containing sig-
nificant quantities of sulfur, metal and/or asphaltenes,
usually requires operation under conditions more severe
than those employed in hydrotreating lighter feeds.
As can be appreciated, satisfactory operation in
processing feeds containing high levels of impurities
under severe process conditions places increased demands
on the catalyst to be employed as the same must exhibit
not only high activity in the presence of impurities and
under severe conditions, but also stability and high
activity maintenance so that fre~uent replacement of
catalyst is not required. ~atalysts containing a Group
VIB metal component, such as a molybdenum or tungsten
-3-
component, promoted by a nickel or cobalt component and
supported on a porous refractory inorganic oxide are well
known and widely used in conventional hydrotreating pro-
cesses; however, the same often are somewhat lacking in
stability and activity maintenance under severe
conditions.
Hensley et al., U.S. Patent No. 4,297,242 have dis-
closed catalysts consisting of at least one active ori-
ginal hydrogenation metal selected from Group VIB deposed
on a catalytically active support comprising alumina and
use thereof with highly desirable results in hydrodesul-
furization of heavy hydrocarbon feeds containing sulfur,
nitrogen, metals and asphaltenes. Hensley et al. also
disclose that such catalysts exhibit lower deactivation
and improved lifetime, even under severe opPrating condi-
tions, as compared to catalysts containing a Group VIB
metal component promoted by a cobalt component.
Hensley et al., U.S. Patent No. 4,212,729,
disclose a two-stage catalytic process for
hydrodemetallation and hydrodesulfuriæation of heavy
hydrocarbon streams containing asphaltenes and a substan-
tial amount of metals. The first stage of the process
comprises contacting the feedstock in a first reaction
zone with hydrogen a~d a demetallation catalyst com-
prising hydrogenation metal selected from Group VIB
and/or Group VIII deposed on a relatively large-pore,
high surface area inorganic oxide support. The second
stage of the process comprises contacting the effluent
from the first reaction zone with a catalyst consisting
essentially of hydrogenation metal selected from Group
VIB deposed on a relatively small pore, catalytically
active support comprising alumina. The second stage
catalyst has a surface area within the range of about 150
m2/gm to about 300 m2/gm, a pore volume within the range
of about 0.4 cc/gm to about 0.9 cc/gm, an average pore
diameter ~ithin the range Gf about 90A to about 160~,
--4--
and a majority of its pore volume in pore diameters
within the range of about 80A to about 130A. More par-
ticularly, the pore volume distribution is such that less
than 40% of its pore volume is in pores having diameters
within the range of about 50A to about 80A, about 45%
to abou~ 90% of its pore volume is in pores having diame-
ters within the range of about 80A to about 130A, and
less than about 15% of its pore volume is in pores having
diameters larger than 130A. More preferably, the cata-
lyst disclosed has a pore volume distribution summarized
as follows:
Pore ~iameter, A % of Pore Volume
50- ~0 <40
1580-100 15-65
100-130 10-50
>130 <15
In terms of the surface area, the pores of the disclosed
2~ catalyst having diameters within the range of about 80A
to about 130A preferably contain about 90 to about
180 m2/gm, and more preferably contain about 120 to about
180 m2~gm, o~ surface area.
It has also been found that addition of a chromium
component to catalysts comprising a Group VIB metal com-
ponent alone or promoted by a Group VIII metal component
gives highly desirable results in a wide range of appli-
cations including high severity hydrotreating applica-
tions. Such catalysts and processes for use thereof are
disclosed in Quick et al., U.S. Patent No. 4,181,602;
Quick et al., U.S. Patent No. 4,188,284; Quick et al.,
U.S. Patent No. 4,191,635; Hensley et al., U.S. Patent
No. 4,224,144, Hensley et al., U.S. Patent No. 4,278,566;
and Hensley et al., U.S. Patent No. 4,306,965.
It has long been known that preparation o~ hydro-
treating catalysts containing Group VIB and Group VIII
metal components supported on a porous re~ractory
~3~ f ~
--5-
inorganic oxide can be improved through the use of
phosphoric acid impregnating solutions of precursors to
the Group VIB and Group VIII metal components or the use
of phosphoric acid as an impregnation aid for the metal
precursors. Thus, Pessimisis, U.S. Patent No. 3,~32,887
discloses stabilization of Group VI and Group VIII
metal-containing solutions through the use of water-so-
luble acids. According to the patentee, in column 3,
lines 6-11, "in its broades~ aspect the invention com-
prises the preparation of stabilized aqueous solutions
which comprise an aqueous solvent having dissolved
therein catalytically active compounds containing at
least one element from Group VI of the periodic table and
one element from Group VIII." Inorganic oxyacids of
phosphorus are included among the disclosed stabilizers,
and the examples of Pessimisis illustrate preparation of
various cobalt-molybdenum, nickel-molybdenum, and nickel-
tungsten catalysts using phosphorus and other acids as
stabilizers. Hydrodesulfurization results with certain
of the cobalt-molybdenum catalysts are presented, and the
patentee suggests that the use of the stabilized solu-
tions may lead to improved hydrodesulfurization activity
in some instances.
Similarly, Colgan et al., U.S. Patent No. 3,287,280
discloses the use of phosphoric acid as an impregnation
aid in prepa.ation of nickel-molybdenum catalysts and
that such use can result in catalysts having improved
hydrodesulfurization activity.
Kerns et al., U.S. Patent No. 3~446!730 disclose
hydrodenitrogenation catalysts comprising at least one of
a nickel component and a Group VI metal component, sup-
ported on a specific alumina, such catalysts being pro-
moted with 0.1 to 2.0 wt.% of a promoter selected from
compounds of phosphorus, silicon and barium. However, at
column 3, lines 26-38, the patentees make the following
remarks with respect to promotion of hydrogenating metals
on the specific alumina disclosed, as follows:
~2~
--6--
"The nature of the hydrogenation component of the
composite catalysts disclosed herein is very impor-
tant, as we have found that not every hydrogenation
component, when composited with the herein disclosed
aluminas, is susceptible to promotion as disclosed
herein. For example, cobalt-containing catalysts
prepared from the special aluminas disclosed herein
are unsuitable for purposes of this invention, not-
withstanding that cobalt is often a component of
conventional denitrogenation catalysts. In fact,
our experiments indicate that the denitrogenative
activity of catalysts comprising cobalt and the
special activated aluminas disclosed herein are
actuallv lessened by the addition thereto of phos-
phorus, silicon or barium."
Hilfman, U.S. Patent No. 3,617,528 discloses hydro-
treating catalysts comprising coextruded nickel and phos-
phorus components and an alumina-containing support. The
catalysts also may contain a Group VIB metal component.
Mickelson et al., U.S. Patent No. 3,706,693 and Hass
et al., U.S. Patent No. 3,725,243 disclose hydrotreating
catalysts prepared by forming an intimate admixture of an
amorphous, foraminous, refractory oxide containing a sub-
stantial proportion of alumina with at least one crystal-
line, ion-exchangeable aluminosilicate containing less
than about 5 wt.% alkali metal oxides, and contacting the
result with an aqueous acidic solution of at least one
Group VIII metal compound, at least one Group VI metal
compound and at least one phosphorus acid at a pH below
about 3 under conditions effective to deposit catalytic
amounts of the metals on the refractory oxide and react
at least a portion of the aluminosilicate with the
aqueous acidic medium. According to the patentees, the
disclosed catalysts are more tolerant of nitrogen than
catalysts prepared without an aluminosilicate component.
Further, Examples 10-13 of both patents illustrate cata-
lysts exhibiting improved hydrodenitrogenation activity
--7-
as compared to catalysts prepared without an
al~lminosilicate component. Reported hydrodesulfurization
activity is slightly worse.
Mickelson, U.S. Patent Nos. 3,7499663; 3,749,664;
3,755,150 and 3,755,196 disclose catalysts comprising
molybdenum~ at least one Group ~III metal component and
phosphorus deposed on a refractory inorganic oxide sup-
port. The '664 patent is directed specifically to the
use of such catalysts for hydrodenitrogenation.
Colgan et al., U.S. Patent No. 3,840,472 disclose
catalysts prepared by impregnation of an alumina support
with stabilized solutions of molybdic oxide and certain
cobalt or nickel salts dissolved in aqueous phosphoric
acid although the patentees suggest -that the presence of
certain amounts of a phosphorus component in the ultimate
catalyst may harm performance, stating the following a~
column 2, lines 23-28:
"In addition, however, phosphoric acid must not be
present in the impregnating solution in an amount
which upon subsequent calcination of the catalyst
material will adversely affect the activity and
strength of the catalyst in use and upon repeated
regenerations to any substantial extent."
Simpson, U.S. Patent No. 4,255,282 discloses hydro-
treating catalysts comprising molybdenum, nickel, and
phosphorus components and a gamma-alumina support, such
catalysts being prepared by a method that involves a pre-
calcination of the gamma-alumina at a ~emperature greater
than 746C. With respect to the phosphorus component,
Simpson teaches that the same often has been included in
hydrotreating catalysts to increase catalyst acidity and
thereby improve activity.
~ipperger and Saum, Chemistry and Uses of Molyb-
denum Proceedin s of the Second International
g
Conference, pages 175-179 (1976) ? report that addition of
phosphoric acid to a catalyst consisting of nickel and
molybdenum supported on alumina resulted in increased
--8--
hydrodenitrogenation activity but that effective
promoters could not be found for catalysts consisting of
cobalt and molybdenum on alumina.
While the patents and publication discussed above
disclose that the use of phosphoric acid in the prepara-
tion of hydrotreating catalysts containing Group VIB and
Group VIII metal components is beneficial to the prepara-
ticns, reported effects on catalytic activity and per-
formance vary significantly. For example, the general
statement in the aforesaid Simpson patent regarding use
of a phosphorus component to increase acidity and thereby
improve activity is contrary to the teaching of Colgan,
U.S. Patent No. 3,840,472 that use of phosphoric acid in
improper amounts can adversely affect catalyst activity
and strength. More specifically, while the aforesaid
Pessimisis patent and Colgan et al., U.S. Patent No.
3,287,280 attribute to use of phosphoric acid in catalyst
preparation, or to phosphoric acid residue content in
finished catalysts, promotional effects in respect of
hydrodesulfurization activity of cobalt-molybdenum and
nickel-molybdenum catalysts, and while certain of the
aforesaid Mickelson patents illustrate a similar influ-
ence on hydrodenitrogenation activity of Group VI and
Group VIII ~etals-containing catalysts, the aforesaid
Ripperger and Saum article teach that phosphoric acid use
leads to improved hydrodenitrogenation activity for nick-
el-molybdenum catalysts but not for cobalt-molybdenum
catalysts. Further, the aforesaid Kerns et al. patent
teaches that hydrodenitrogenation activity of cobalt-con-
taining catalysts in general, and nickel-molybdenum-co-
balt catalysts in particular, decreases when the specific
alumina support disclosed therein is employed and when a
phosphorus promoter is used.
Notwithstanding the diverse teachings of the afore-
said patents and publication in respect of stabilization
and promotion of hydrotreating catalysts, there is a con-
tinuing need for development of improved catalysts.
_9
OBJECTS OF THE INVENTION
It is therefore a general object of ~his invention
to provide an improved hydrotreating catalyst as well as
hydrotreating processes which employ such catalyst.
A further object of the invention is to provide a
catalyst of improved stability and lifetime ~nder high
severity hydrotreating conditions.
Another object of the invention is to provide for
such improvements by simple and inexpensive methods for
catalyst preparation and without the need for expensive
reactants or complicated preparative techniques.
A more specific object of the invention is to pro-
vide a catalyst of improved activity and stability for
hydrotreating high nitrogen hydrocarbon feeds under
severe conditions as well as methods for the use of such
catalyst.
It is another object of this invention to provide a
catalyst of improved activity and stability for hydro-
treating high sulfur hydrocarbon feeds under severe con-
ditions, and also to provide methods for the use of suchcatalysts.
It is a further object of this invention to provide
a catalyst of improved activity and stability for hydro-
treating high metal hydrocarbon feeds under severe condi-
tions and to provide methods for the use of such cata-
lyst.
It is a related object of this invention to provide
an improved process for the hydrodemetallation and hydro-
desulfuri~ation of heavy hydrocarbon streams containing
metals and sulfur and to provide an improved catalyst for
use in such process.
Other objects of the lnvention will be apparent to
persons skilled in the art from the following description
~;~ and appended claims, and upon reference to the accompa-
nying drawings.
-
.
: `
-10-
SUMMARY OF THE INVENTION
. _
These objects are achieved by the catalytic composi-
tion of the present invention comprising a hydrogenating
component supported on the surface of a porous refractory
inorganic oxide support, wherein the hydrogenating compo-
nent consists essentially of (1) a metal component in
which the metal is selected from Group VIB of the
Reriodic Table and (2) a phosphorus component and wherein
the support is free of a zeolite component. The present
invention is also a method for hydrotreating a hydro-
carbon feed in the presence of such catalyst.
In a preferred embodiment, the aforesaid catalyst
has a pore volume within the range of about 0.4 cc/g~l to
about 0.9 cc/gm, a surface area within the range of about
130 m2/gm to about 300 m2/gm, an average pore diameter
within the range of about 90A to about 160A, and a pore
volume distribution such that less than 40% of its pore
volume is in pores having diameters within the range of
about 50A to about 80A, about 45% to about 90% of its
pore volume is in pores having diameters within the range
of about 80A to about 130A, and less than about 15% of
its pore volume is in pores having diameters larger than
130A. In this embodiment, it is also preferred that the
catalysts comprises from about 8 wt.% to about 22 wt.%
product of the Group VIB metal component, calculated as
the metal oxide, and from about 0.5 wt.% to about 3 wt.%
of the phosphorus component, calculated as elemental
phosphorus and based on the weight of the catalyst~
In another preferred embodiment, the aforesaid cata-
lyst has a pore volume within the range of from about 0.3cc/gm to about 1.2 cc/gm, a surface area within the range
of from about 100 m2/gm to about 35;! m2/gm, and an
avera~e pore diameter within the range of from about
o O
70 A to about 120 A. In this embodiment, it is also
preferred that the catalyst comprises from about 15 wt.%
to about 22 wt.% of the Group VIB metal component, calcu-
lated as the metal oxide and based on the weight of the
-11-
catalyst, and from about 0.5 wt.% to about 3 wt.% of the
phosphorus component, calculated as elemental phosphorus
and based on the weight of the catalyst.
In a further preferred embodiment, the aforesaid
catalyst has a pore volume within the range of from about
0.7 cc/gm to about 1.7 cc/gm, a surface area within the
range of from about 100 m2/gm to about 400 m2/gm, and an
average pore diameter within the range of from about
125 A to about 350 A. In this embodiment, the hydro-
genation component consists essentially of a Group VIBmetal component 9 a phosphorus component, and optionally a
Group VIII metal component. The Group VIB metal compo-
nent is at a concentration within the range of from about
1 wt.% to about 30 wt.% calculated as the metal oxide and
based on the weight of the catalyst. The phosphorus com-
ponent is present at a concentration of from about 0.5
wt.% to about 3 wt.%, calculated as elemental phosphorus
and based on the weight of the catalyst. The Group VIII
metal component is present at a concentration up to about
15 wt.%, calculated as the metal oxide and based on the
weight of the catalyst.
BRIEF DESCRIPTION OF THE DRAWINGS
For a more complete understanding of this invention,
reference should now be made to the accompanying draw
ings. In the drawings:
FIG. 1 contains a plot of the API gravities of the
liquid products from a two-stage hydrodemetallation and
hydrodesulfurization of a heavy hydrocarbon stream, in
which a catalyst of the present invention was employed in
the hydrodesulfurization stage;
FIG. 2 contains a plot of the concentra~ions of
metals in the liquid products from a two-stage hydrodeme-
tallation and hydrodesulfurization of a heavy hydrocarbon
stream, in which a catalyst of the presen~ invention was
employed in the hydrodesulfurization stage; and
~3~i~7~
-12-
FIG. 3 contains a plot of the solids concentrations
of the liquid products from a two-stage hydrodemetalla-
tion and hydrodesu]furization of a heavy hydrocarbon
stream, in which a catalyst of the present invention was
employed in the hydrodesulfurization stage.
DETAILED DESCRIPTION OF THE INVENTION
INCLUDING PR~FERRED EMBODIMENTS
Stability and activity maintenance of the catalysts
of the present invention, particularly under high sev-
erity hydrotreating conditions and in the presence of
high levels of impurities, are comparable or superior to
those of high stability catalysts, such as those of
Hensley et al. '242, in which the original active hydro-
genation metal is selected from Group VIB, as well asthose of Quick et al. '602, '284 and '635 and Hensley et
al. '144, '566 and '965, in which a stabilizing chromium
component is incorporated into hydrogenating components
comprising another metal of Group VIB or combinations
thereof with a metal of Group VIII. Further, the cata-
lysts of the present invention exhibit activities compar-
able or superior to those of conventional catalysts
wherein the hydrogenating component contains a Group VIB
metal component alone or promoted by a Group VIII metal
component. As such, the invented catalysts are particu-
larly well suited for hydrotreating feeds containing
nitrogen, sulfur, metals and/or high boiling components
under severe hydrotreating conditions.
Such a desirable combination of activity, stability
and activity maintenance could not have been predicted
from the patents and publication discussed hereinabove.
To the extent, if any, the high stability o~ the invonted
catalysts might be viewed as paralleling the stability of
the catalysts of Hensley et al. '2~2, which contain a
metal from Group VIB as the sole active original hydro-
genating metal, the invented catalyst's maintenance o
sllch stability in the presence of an activity-promoting
~2f~
-13-
phosphorus component was not expected. Further, to the
extent the aforesaid patents and publication relating to
the use of phosphoric acid in the preparation o~ hydro^
treating catalysts may be viewed as sugges~ive of some
activity-promoting effect exerted by the phosphoric acid
or residues thereof, reported effects vary significantly
depending on the particular metals contained in a hydro-
~enating component, and in any event, there is no sugges-
tion of a promotional effect on activity of the Group VIB
metals alone.
Briefly, the improved hydrotreating catalysts of
this invention comprise a hydrogenating component con-
sisting essentially of (1) a metal component in which the
metal is selected from Group VIB and (2) a phosphorus
component, such hydrogenating component being deposed on
the surface of a support component comprising a porous
refractory inorganic oxide and free of a zeolite compo-
nent. Preferred catalysts are those in which the phos-
phorus component is a phosphoric acid residue, the same
most preferably being prepared by impre~nation of a sup-
port component comprising a porous refractory inorganic
oxide with an impregnating solution containing phosphoric
acid and one or more precursors to the aforesaid metal
component. Such catalysts are used in hydrotreating
hydrocarbon feeds containing nitrogen, culfur, metals
and/or high boiling components wherein the feed is con-
tacted with hy~rogen under hydrotreating conditions, par-
ticularly severe hydrotreating conditions, in the pres-
ence of the catalyst.
In greater detail, the hydrogenating component of
the invented catalyst comprises (1) a metal component in
which the metal is selected from Group VIB and (2) a
phosphorus component. The Group VIB metal can be molyb-
denum~ chromium, tungsten or a binary or ternary combina-
tion thereof. The Group VIB metal is present in the
metal component in elemental form, as an oxide or sul-
fide, as an oxygenated phosphorus species or as a
2~ 3 ~7
-14-
combination thereof. Preferably, the Group VIB metal of
the metal component is molybdenum alone or in combination
with chromium or tungsten, because molybdenum exhibits
superior hydrogenation activity when promoted by a phos-
phorus component. Most preferably, a molybdenum compo-
nent is the sole Group VIB metal component in the metal
component of the hydrogenation component. The hydrogen-
ating component also contains a phosphorus component
which is present in a form effective to promote the
activity of the Group VIB metal component. A preferred
phosphorus component is a phosphoric acid residue
remaining in the hydrogenation component as a result of
slmultaneous or sequential impregnation of support compo-
nent with a solution or solutions consisting essentially
of a precursor to the metal component and phosphoric acid
in a suitable solvent, for example, water. While not
wishing to be bound by theory, it i5 believed that phos-
phoric acid residues present in the hydrogenating compo-
nent are present in the form of one or more oxides, a
phosphate anion, compounds of the Group VIB metal or
metals of the hydrogenating component and/or polymeric
species containing recurring phosphorus-oxygen units
and/or phosphorus-oxygen-Group VIB metal groups.
Presently preferred catalysts according to the pre-
sent invention comprise about 1 to about 50 weight per-
cent hydrogenating component and about 50 to about 99
weight percent support. In greater detail, the Group VIB
metal content preferably ranges from about 1 to about 30
weight percent, calculated as the metal o~ide, that is,
~oO3, WO3, Cr2O3. The phosphorus component is present in
an amount effective to promote the activity, the amount
preferably ranging from about 0.1 to about 5 weight per-
cent, calculated as elemental phosphorus, in order to
promote the activity without adversely affecting the
strength and other important catalyst physical proper-
ties. It is to be understood that the weight percentages
set forth herein are based upon total catalyst weight
f~
-15-
after calcination.
The support on which the aforesaid hydrogenating
component is deposed comprises at least one porous
refractory inorganic oxide, specific examples of which
include silica, alumina, silica-alumina, zirconia,
titania, magnesia, boria and the like. Of course, combi-
nations of metal oxides also are contemplated. Modified
porous refractory inorganic oxides, such as fluorided
aluminas and chlorided silica-alumina also are contem-
plated. Supports containing minor amounts of one or moreoxides of phosphorus, for example, up to about 2 wt.%,
calculated as phosphorus, in combination with one or more
of the aforesaid porous refractory inorganic oxides also
can be employed although the same are not preferred,
because the presence of phosphorus oxide in the support
can be detrimental to promotion of the hydrogenating
metal component with phosphorus. Furthermore, the pres-
ence of a zeolite component in the support of the cata-
lyst of this invention changes the essential character of
the catalyst and hence is not contemplated for the cata-
lyst of this invention.
As indicated hereinabove, a wide range of supports
is suitable for impregnation according to this invention.
The support preferably is calcined prior to any impregna-
tion in which phosphorus component precursor is to bepresent as hydroxyl groups of the support may react with
the precursor and thereby hinder incorporation of suffi^
cient phosphorus component into the hydrogenating compo-
nent. The support can be used in any suitable form, for
example, as extrudates, spheres or powder. Fro~ the
standpoint of attaining desirable hydrotreating perform-
ance, presently preferred supports are aluminas and sili-
ca-aluminas containing up to about S0 wt.% of silica.
More preferably, the support is an alumina or a silica-
alumina containing up to about 50 w~./O of silica Inaddition, it is preferred that the ~inished catalysts
have a BET surface area of at least abou~ lO0 m2/gm, a
, :
3~
-16-
pore volume of about 0.3 to about 1.7 cc/gm, both as
determined by nitrogen desorption, and an average pore
diameter within the range of from about 70 A to about
350 A.
When the catalyst of this invention is used in a
hydrotreating operation in which removal of sulfur is a
major concern, for example, with a feed comprising a
vacuum or atmospheric resid, it is highly preferred that
the catalyst has a pore volume within the range of about
0.4 cc/gm to about 0.9 cc/gm, a surface area within the
range of about 130 m2/gm to about 300 m2/gm, an average
pore diameter within the range of about 90A to about
160A, and a pore volume distribution such that less than
40% of its pore volume is in pores having diameters
within the range of about 50A to about 80A, about 45%
to about 90% of its pore volume is in pores having diame-
ters within the range of about 80A to about 130A, and
less than about 15% of its pore volume is in pores having
diameters larger than 130A. More preferably, the cata-
lyst of this invention has a pore volume distribution
summarized as follows:
o
Pore Diameter, A /O of Pore Volume
59- 80 <40
80-100 15-65
100-130 10-50
>130 <15
Most preferably, the catalyst of this invention has a
pore volume within the range of about 0.5 cc/gm to about
0.7 cc/gm, a surface area within the range of about 140
m2/gm to about 250 m2/gmj an average pore diameter within
the range of about llOA to about 140A, and a pore
volume distribution summarized as follows:
f~i
-17-
Pore Diameter, A % of Pore Volume
50- 80 <~0
80-100 25-65
100-130 10-50
>130 <5
In terms of the surface area, when the catalyst of
this invention is used as a hydrodesulfurization catalyst
with a feed comprising a vacuum or atmospheric resid, the
catalyst pores having diameters within the range of about
80A to about 130A preferably contain about 90 m2/gm to
about 180 m2/gm, and more preferably contain about 120
m2/gm to about 180 m2/gm, of surface area in order to
attain maximum desulfurization activity.
When used as a desulfurization catalyst, the cata-
lyst of the present invention preferably comprises from
about 8 wt.% to about 22 wt.% of the Group VIB metal com-
ponent, calculated as the metal oxide and based on the
weight of the catalyst, and from about 0.5 wt.% to about
3 wt.% of the phosphorus component, calculated as ele-
mental phosphorus and based on the weight of the cata-
lyst.
When the catalyst of this invention is used in a
hydrotreating operation in which removal of nitrogen is a
major concern, for example, with a feed comprising a
whole shale oil or shole oil fraction, it is highly pre-
ferred that the catalyst has a pore volume within the
range of about 0.3 cc/gm to about 1.2 cc/gm, a surface
area within the range of from about loO m2/gm to about
350 m2/gm and an average pore diameter within the range
of from about 70 A to about 120 A. Ln such case, it is
also preferred that the catalyst comprise from about 15
wt.% to about 22 wt.% of the Group VIB metal component,
calculated as the metal oxide and based on the weight of
the catalyst, and from about 0.5 wt.% to about 3 wt.% of
the phosphorus component, calculated as elemental phos-
phorus and based on the weight of the catalyst.
-18-
When the catalyst of this invention is used in a
hydrotreating operation in which removal of metals is a
major concern, for example, with a feed comprising a high
metals resid, it is highly preferred that the catalyst
has a pore volume within the range of from about 0.7
cc/gm and 1.7 cc/gm, a surface area within the range of
from about 100 m2/gm to about 400 m2/g~, an average pore
diameter within the range of from about 125 A to about
350 A, a Group VIB metal component concentration from
about 1 wt.% to about 30 wt.%, preferably to about 20
wt.%, calculated as the metal oxide and based on the
weight of the catalyst, a Group VIII metal component con-
centration of up to about lS wt.%, preferably from about
0.5 wt.% to about 12 wt.%, calculated as the metal oxide
and based on the weight of the catalyst 9 and a phosphorus
component concentration of from about 0.5 wt.% to about 3
wt.%, calculated as elemental phosphorus and based on the
weight of the catalyst. In this context, the pore size
or pore volume distribution of the demetallation could be
bimodal so long as the above pore volume, surface area
and average pore diameter requirements are met.
The invented catalysts are prepared by impregnation
of a support comprising at least one porous refractory
inorganic oxide with a solution or solutions consisting
essentially of precursors to the metal and phosphorus
components of the final catalyst in a suitable solvent
and calcination of impregnated support. Most preferably,
simultaneous impregnation of a support with phosphorus
and metal component precursors, ~ollowed by calcination
of the impregnated support, is conducted in order to max-
imize the promotional effect of the phosphorus component
of the final catalyst. However, sequential impregnation
with phosphorus and metal component precursors also gives
good results. A preferred sequential impregnation
involves impregnation of support with phosphorus compo-
nent precursor followed by calcination, followed by
impregnation with metal component precursor, followed by
~2~
-19-
final calcination.
The mechanics of impregnating a support are well
known to persons skilled in the art. A technique pre-
ferred for the sake of simplicity involves forming a
solution or solutions of appropriate compounds in a suit-
able solvent and contacting a support with an amount or
amounts of solution or solutions sufficient to fill the
pores of the support. Useful precursors to the metal
component of the invented catalysts also are well known
to persons skilled in the art. Specific examples include
ammonium chromate, ammonium dichromate, chromium(lII)
nitrate, chromium acetate, ammonium heptamolybdate, ammo-
nium paramolybdate, molybdic anhydride, phosphomolybdic
acid and ammonium tungstate.
Phosphorus component precursors useful in prepara-
tion of the invented catalysts include phosphoric acid,
phosphorous acid, hypophosphorous acid and pyrophosphoric
acid. Esters of such acids also can be used although
they are not preferred. Phosphorus oxides, such as P2O5
and P4O6, also can be used. Salts of the aforesaid acids
and esters also are contemplated. Specific examples of
these include ammonium phosphate, diammonium hydro~en
phosphate and ammonium dihydrogen phosphate. As the pre-
ferred catalysts according to this invention are those in
which a phosphoric acid residue is present, phosphoric
acid is the preferred phosphorus component precursor.
Most preferably, dilute or concentrated aqueous phos-
phoric acid is used as an impregnating solvent for the
Group VIB metal component precursor. Other phosphorus
component precursors can be employed in the form of a
solution in a suitable solvent 5 such as water or alcohol,
or the same can simply be dissolved in a solution or
solutions containing one or more Group VIE metal compo-
nent precursors. Phosphorus compound concentrations vary
depending on solubility, amount of phosphorus component
desired in the ultimate catalyst and amount of solution
that can be accommodated by the particular support to be
~3~'6
-20-
used as can be appreciated by persons skilled in the art.
It of course must be recognized in the discussion of
impregnation techniques hereinabove, that when the cata
lyst of this invention is used as a hydrodemetallation
catalyst, a Group VIII metal component precursor can be
used in place of, or in addition to, the Group VIB metal
component precursor in the impregnation process.
Following impregnation of support with one or more
precursors to the hydrogenating component, the impreg-
nated support is calcined. Calcination preferably isconducted at temperatures of at least about 425C and
more preferably at least about 535C for a period of at
least about 1/2 hour. The calcination is conducted in
the presence of a gas containing molecular oxygen, air
being preferred from the standpoint of convenience and
cost. While not required, it is desirable to dry the
impregnated support at a temperature high enough to drive
off excess solvent from the impregnation step prior to
calcination. When water is used as the solvent in
impregnation, preferred temperatures are at least about
120C. Drying times of at least about 1/2 hour are pre-
ferred.
Prior to hydrotreating use of the invented cata-
lysts, if desired, sulfiding can be conducted to sulfide
and partially reduce the metal or metals of the hydrogen-
ating component. A sulfiding treatment that is preferred
from the standpoint of convenience comprises heating the
catalyst to from about 120C to about 180C and con-
tacting the catalyst with a flowing gaseous mixture of
hydrogen sulfide and hydrogen under pressure for from
about 1/2 to about 2 hours, raising the temperature to
from about 175C to about 235C with continued flow of
the gaseous mixture for an additional 1/2 to about 2
hours, raising the temperature to from about 340C to
about 400C, and con~acting with additional hydrogen-hy-
drogen sulfide gas mixture for an additional period of
time, preferably from about 1/2 to about 2 hours. The
:
G
-21-
gas should be employed in an amount effective to provide
at least about 110 percent of the stoichiometric amount
of hydrogen sulfide needed to sulfide the metal or metals
of the hydrogenating component. The concentration of
hydrogen sulfide in the gaseous mixture is not critical.
While the above-described sulfiding ~reatment tech-
nique is preferred from the standpoint of convenience,
other methods can be employed. For example, the catalyst
can be contacted with carbon disulfide or a hydrocarbon
oil containing sulfur can be passed over the catalyst for
a time sufficient to convert the hydrogenating component
to sulfide form.
Preferably, sulfiding treatment is conducted while
the catalyst is disposed in a hydrotreating reaction zone
because on conclusion thereof, the flow of hydrogen
sulfide or other source of sulfide can be discontinued
and hydrogen partial pressure and temperature adjusted to
operating levels. Once operating conditions are
achieved, hydrocarbon feed is simply introduced into the
reaction zone.
Hydrotreating according to the present inventi.on can
be conducted in either fixed bed or expanded bed opera-
tions. Preferred catalysts for use in fixed bed pro-
cesses are those having an average particle size of from
about 0.8 millimeter to about 3.2 millimeters effective
diameter. Pellets, spheres, and/or extrudate are contem-
plated for fixed bed use. In addition, more complicated
shapes, such as clover leaf, cross-shaped or C-shaped
catalyst are contemplated. Preferred catalysts for
expanded bed use are spheres or extrudates having diame-
ters of from about 0.8 millimeter to about 1.6 millime-
ters.
~ ydrocarbon feeds to be hydrotreated according to
this invention are those containing sufficiently high
levels of nitrogen, sulfur, metals or high boi]ing compo-
nents as to hinder direct use in more conventional
refining operations, such as catalytic cracking or
~3~3~7~
-22-
hydrocracking. Examples of feeds that can be treated
according to this invention include petroleum hydrocarbon
streams, hydrocarbon streams derived from coal, hydro-
carbon streams derived from tar sands and hydrocarbon
streams derived from oil shale. Typical examples of
petroleum hydrocarbon streams include petroleum distil-
lates, virgin gas oils, vacuum gas oils, coker gas oils
and atmospheric and vacuum resids. Hydrocarbon streams
derived from oil shale, such as whole shale oil or a
fraction thereof, are also particularly well suited.
Preferred feeds are those containing at least about ~.l
wt.% nitrogen or resids containing high concentrations of
sulfur and/or metals.
The conditions employed in operation of the process
of the present invention will vary with the particular
hydrocarbon stream being treated, with mild conditions
being employed in the hydrotreating of light distillates,
such as naphtha and kerosene, typically 232C to 316C
and about 690 kPa to 4,137 kPa of hydrogen partial pres-
sure. Heavier materials can be treated under conditionsof about 3.45 MPa to 20.75 MPa of hydro~en partial pres-
sure, an average catalyst bed temperature within the
range of about 315C to about 443C, with an LHSV (liquid
hourly space velocity) within the range of about 0.1 to
about 5 volumes of hydrocarbon per hour per vGlume of
catalyst, and a hydrogen recycle rate or hydrogen addi-
tion rate within the range of about 89 m3/m3 to 3,560
m /m .
For the removal of nitrogen from feeds containin~ at
least 0.1 wt.% nitrogen, hydrodenitrogenation conditions
are preferred. Best results in removing nitrogen from
whole shale oil are obtained un~er hydrodenitrogenation
conditions comprising about 8.3 MPa to about 17.3 MPa
total pressure, average catalyst bed temperatures within
the range of about 388C to about 427C, an LHSV of about
0.3 to about 2 volumes of hydrocarbon per hour per volume
of catalyst, and a hydrogen recycle rate or hydrogen
.
~2~ 6
-~3-
addition rate within the range of about 178 m3/m3 to
about 1780 m3/m3.
For the removal of metals from feeds containing at
least about 150 ppm of total metals, hydrodemetallation
conditions are preferred and include a tempera$ure of
from about 371C to about 454C, a pressure of from about
7 MPa to about 21 MPa, a hydrogen addition rate of from
about 178 m3/m3 to about 1780 m3/m3 and a space velocity
of from about 0.1 to about 5 volumes
of feed per volume of catalyst per hour.
For the removal of sulfur from feeds containing at
least about 0.1 wt.% sulfur, hydrodesulfuriæation condi-
tions are preferred. Best results in removing sulfur
from a vacuum or atmospheric resid are hydrodesulfuriza-
tion conditions comprising about 12.4 MPa to 20.7 MPa
total pressure, about 399C to 427C average catalyst bed
temperature, about 178 m3/m3 to 1780 m3/m3 hydrogen rate
and about 0.1 to about 5 volumes feed per volume catalyst
per hour LHSV.
It is of course understood that, in this context,
"resid" includes a resid which has been subjected to a
prior treatment such as a hydrodemetallation treatment.
For example, when the feed comprises a metal-containing
heavy hydrocarbon stream, it is known to be highly advan-
tageous to employ a two-stage hydrotreatment of the
stream wherein a demetallation catalyst is employed in
the first stage and provides demetallated e~fluent which
is contacted in the second stage with a desulfurization
catalyst. In a preferred embodiment of this invention, a
catalyst of the present invention having the aforesaid
preferred pore volume, surface area, average pore diam-
eter and pore size distribution is employed as the desul-
furization catalyst in the a~oresaid two-stage hydro-
treatment process.
Thus, such preferred embodiment of the present
invention comprises a two-stage process for the hydro
demetallation and hydrodesulfurization of a hydrocarbon
:,
~2~
-24-
feedstock containing asphaltenes and a substantial amount
of metals. Such feedstock generally contains asphal-
tenes, metals, nitrogen compounds and sulfur compounds.
It is to be understood that the feedstocks that are to be
treated by the preferred two-stage hydrotreatment process
of the present invention contain from a small amount of
nickel and vanadlum, for example, about 40 ppm up to more
than 1,000 ppm of the combined total amount of nickel and
vanadium, up to about 25 wt.% of asphaltenes. This pre-
ferred two-stage hydrotreatment process is particularly
useful in treating feedstock with a substantial amount of
metals, for example, one containing 150 ppm or more of
nickel and vanadium, and with a sulfur content in the
range of about 1 wt.% to about 10 wt.%. Typical
feedstocks tha~ can be treated satisfactorily by the pre-
ferred two-stage hydrotreatment process of the present
invention also contain a substantial amount of components
that boil appreciably above 538C. Examples of typica~
feedstocks are crude oils, topped crude oils, petroleum
hydrocarbon resids, both atmospheric and vacuum resids,
oils obtained from tar sands and resids derived from tar
sands oil, hydrocarbon streams derived from coal, and
blends of any of the aforesaid resids with lower boiling
materials. Such hydrocarbon streams contain organome-
tallic contaminants which create deleterious effects invarious refining processes that employ catalysts in the
conversion of the particular hydrocarbon streaM being
treated. The metallic contaminants that are found in
such feedstocks include, but are not limited to, iron,
vanadium and nickel.
In this preferred embodiment, the first-stage cata-
lyst and the second-stage catalyst can be employ~d in a
single reactor as a dual bed or the two catalysts can be
employed in separate, sequential reactors, and various
combinations of these two basic reactor schemes can be
employed to achieve flexibility of operation and product
upgrade. In any event, the feed is contacted with the
;
3~
--25-
demetallation catalyst first and then with the
desulfurization catalyst. In commercial operation,
either of the basic reactor schemes described can com-
prise multiple parallel beds of the catalyst. The direc-
tion of flow of the feedstock can be upward or downward.In any reactor scheme used in the process of this inven-
tion, the volumetric ratio of first-stage catalyst to
second-stage catalyst can be within a broad range, pre-
ferably within about S:l to about 1:10 and more prefer-
ably within about 2:1 to abcut 1:5.
The first-stage, demetallation catalyst in the
method of the present invention comprises a hydrogenation
component and a large-pore, high surface area inorganic
oxide support. Suitable demetallation catalysts comprise
catalytic amounts of a hydrogenation component typically
including a Group VIB metal, a Group VIII metal or a mix-
ture of Group VIB and Group VIII metals deposed on a
relatively large-pore, high surface area porous inorganic
oxide support, suitably alumina, silica, magnesia, zir-
conia and similar materials. This first-stage catalyst
has a surface area of about 100 m2/gm to about 400 m2/gm,
an average pore diameter of about 125A to about 350A,
and a pore volume of about 0.7 cc~gm to about 1.7 cc/gm.
Suitably, the composition of the demetallation catalyst
comprises from about 1 wt.% to about 30 wt.% of the Group
VIB metal, calculated as the oxide, and/or from about 0.5
to about 12 wt.% of the Group VIII metal, calculated as
the oxide, based upon the total weight of the composi-
tion. The Group VIB and Group VIII classifications of
the Periodic Table of Elements can be found on page 628
of Webster _ Seventh New Collegiate Dictionary, G. & C.
Merriam Company, Springfield, Massachusetts, V.S.A.
(1965). While calculated as the oxide, the hydrogenation
metal components of the catalyst can be present in the
elemental form or as the sulfide or oxide thereof.
Commercially available catalysts tha~ are suitable
for use as the first-stage, demetallation catalyst
-26-
include American Cyanamid's 1442B and Amocat lA~, both
bimodal. In addition, the embodiment of the catalyst of
the present invention which is described hereinabove as
employed in a hydrotreatment operation in which demetal-
lation is a major concern, can also be employed as thefirst-stage demetallation catalyst.
The first-stage catalyst used in the process of the
present invention can be prepared by the typical commer-
cial method of impregnating a large-pore, high surface
area inorganic oxide support. Appropriate commercially
available alumina, preferably calcined at about 426C. to
872C, for about 0.5 to about 10 hours, can be impreg-
nated to provide a suitable lead catalyst having an
average pore diameter of about 125A to about 350A, a
surface area ranging from about 100 m2/gm to about 400
m2/gm, and a pore volume within the range of about 0.7
cc/gm to about 1.7 cc/gm. The alumina can be impregnated
with a solution, usually aqueous, containing a heat-de-
composable compound of the metal(s) to be placed on the
catalyst, and then drying and calcining the impregnated
material. The drying can be conducted in air at a tem-
perature of about 65C to about 204C for a period of 1
to 16 hours. Typically, the calcination can be carried
out at a temperature of about 426C to about 648C for a
period of from 0.5 to 8 hours.
The finished second-stage catalyst that is employe~
in the process of the present invention has a pore volume
within the range of about 0.4 cc/gm to about 0.9 cc/gm, a
surface area within the range of abou~ 130 m2/gm to about
300 m2/gm, and an average pore diameter within the range
of about 90A to about 160A. Preferably, the catalyst
possesses a pore volume within the range of about 0.5
cc/gm to about 0.7 cc/gm, a surface area within the range
of about 14G m2/gm to about 250 m2/gm, and an average
pore diameter within the range of about llOA to about
140A.
-27-
In order to maximize the desulfurization activity,
the second-stage catalyst should have less than 40% of
its pore volume in pores having diameters within the
range of about 5QA to about 80A, about 45% to about 90%
of its pore volume in pores having diameters within the
o O
range of about 80A to about 130A, and less than about
15% of i$s pore volume in pores having diameters that are
larger than 130A. More preferably, the second-stage
catalyst has a pore volume distribution summarized as
follows:
o
Pore Diameter, A % of Pore Volume
50~ 80 <40
80-100 15-65
15100-130 10-50
>130 <15
Most preferably, the second-stage catalyst has a pore
volume distribution summarized as follows:
O
Pore Diameter, A % of Pore Volume
50~ 80 <40
80-100 25-65
100-130 10-50
25 >130 <5
o o
The catalyst pores having diameters 80A to 130A
preferably should contain from about 90 m2/gm to 180
m2/gm, and more preferably 120 m2/gm to 180 m2/gm, of
surface area in order to attain maximum activity.
In both the first reaction zone and the second reac-
tion zone, operating conditions for the hydrotreatment of
heavy hydrocarbon streams, such as petroleum hydrocarbon
resids and the like, comprise a pressure within the range
of about 7 MPa to about 21 MPa, an average catalyst bed
temperature within the range of about 371C to about
454C~ a LHSV within the range of about U.l volume of
-28-
hydrocarbon per hour per volume of catalyst to about 5
volumes of hydrocarbon per hour per volume of catalyst,
and a hydrogen recycle rate or hydrogen addition rate
within the range of about 178 m3/m3 to about 2,671 m3/m .
Preferably, the operating conditions comprise a total
pressure within the range of about 10 MPa to about 18
MPa; an average catalyst bed temperature within the range
of about 387C to about 437C; a LHSV within the range of
about 0.1 to about 1.0; and a hydrogen recycle rate or
hydrogen addition rate within the range of about 356
m3/m3 to about 1,780 m3/m3.
The following examples are intended to illustrate
the present invention without limiting the scope thereof.
Example I
A control catalyst, identified hereinafter as Cata-
lyst I and containing 15.0 wt.% MoO3 supported on gamma-
alumina, was prepared as follows.
300 gm gamma-alumina (obtained ~rom Continental Oil
Company and identified as Catapal) were calcined in an
oven at 500C for 3 hours The calcined product, having
BET surface area of 230 m /gm, pore volume of 0.65 cc/gm
as determined by nitrogen adsorption using a Digisorb
2500 instrument and average pore diameter of 113A calcu-
lated as (4V x 104)/A was placed in a desiccator until
used.
To 85.00 gm of the calcined gamma-alumina in a por-
celain dish were added 18.40 gm ammonium heptamolybdate
(NH4)6Mo7O24 4H2O dissolved in 33 ml water and 15 ml con-
centrated ammonium hydroxide, the latter having been used
to completely dissolve the ammonium heptamolybdate. The
amount of solution employed was sufficient to fill the
pores of the alumina support. The impregnated support
was allowed to stand at ambient temperature (about 25C)
for one hour and then the result was dried for one hour
at 250F (121C) in an oven and calcined in air for one
hour at l,000F (538C). The resulting catalyst was
ground and screened to 14/20 mesh and then tested for
~z~
-29-
activity according to Example I~.
Example II
A catalyst according to the invention, identified
hereinafter as Catalyst II and containing 15.0 wt.% MoO3
and 1.3 wt.% P, was prepared as follows.
Following the procedure of Example I, 18.40 gm ammo-
nium heptamolybdate and 4.83 gm 85% phosphoric acid dis-
solved in 46 ml water were added to 82.02 gm of the
calcined gamma-alumina from Example I. After standing
for one hour at ambient temperature, ~he impregnated sup-
port was dried, calcined and crushed and screened as in
Example I. The resulting catalyst was tested for
activity according to Example IV.
Example III
A second control catalyst, identified hereinafter as
Catalyst III and again containing 15.0 wt.% MoO3, was
prepared by a two-step impregnation as follows.
To 85.00 gm of the calcined gamma-alumina from
Example I were added 9.2 gm ammonium heptamolybdate dis-
solved in 52 ml water. After standing for an hour atam~ient temperature, the impregnated support was dried
and calcined as in Example I. To the result were added
9.20 gm ammonium heptamolybdate dissolved in 52 ml H2O
and the result again was allowed to stand, and then dried
and calcined as in ~xample I. The calcined catalyst waC,
crushed and screened to 14/20 mesh as in Example I and
tested according to Example IV.
Example IV
The catalysts from Examples I-III were tested in a
81 cm long, 0.95 cm inner diameter, vertical reactor
equipped with automatic controls for monitoring tempera-
ture, feed rate and hydrogen partial pressure. In each
test, 15.00 cc catalyst were loaded into the reactor and
sulfided by passing 8 vol.% H2S in hydrogen over the
catalyst at about 0.03 m3/hr and total pressure of about
2 MPa at 148C for one hour, followed by 204C for one
hour, and then 375C for one hour. On completion of
:
-30-
sulfiding, temperature was increased to 404C, the feed
was introduced via a positive displacement Ruska pump at
a liquid hourly space velocity ~LHSV) of 0.64 volume feed
per volume catalyst per hour, and the reactor was charged
with hydrogen to 12 MPa. Each test was conducted for 6-7
days with daily sampling of liquid product recovered
using a high pressure separator.
The feed used in all tests was a whole shale oil
generated in situ from oil shale and having properties as
shown in Table 1. Also shown in the table are properties
of samples of product taken on the last day of each test.
~2~
-31-
Table 1
Test Number
Pro ert Feed l 2 3
P Y , 1 ~
Catalyst NA~l~ I II III
Length of test (days) NA 7 7 6(2)
Carbon ~wt.%) 83.54 86.1386.16 ND
Hydrogen (wt.%) 11.85 13.7313.88 ND
Sulfur (wt.%) 1.75 0.007 0.017 ND
Oxygen (wt.%) 1.34 ND ND ND
Total nitrogen (wt.%) 1.72 0~12 0.031 0.24
Basic nitrogen (wt.%) 0.83 0.09 0.024 0.11
Liquid product (gm)NA 166 157 70.1
API gravity () 23.1 37.7 38.7 37.7
Pour point (C) +21 +26 +21 ND
Simulated distil-
lation (wt.%)
Temp. (C)
<182 1.0 6.5 8.0 ND
182-343 42.0 61.5 56.0 ND
343-538 51.5 32.0 35.0 ND
>538 5.5 0 1.0 ND
H2 consumption (m3/m3) NA 255 257 ND
Cl-C4 yield ~wt.%) NA 3.5 3.3 ND
5 (1) In this and all subsequent tables, "not applicable"
is abbreviated "NA" and "not determined" is abbrevi-
ated "ND."
(2) On day 6 of this test the feed pump was off for
about 20 hours. Hydrogen flow was maintained during
this period.
(3) In view of the poor nitrogen removal exhibited by
Catalyst III, most other product properties were not
determined.
From the table it can be seen that Catalyst II
according to the present invention exhibited superior
hydrodenitrogenation activîty as measured by both total
3Pfl6
and basic product nitrogen. Based on first order
hydrodenitrogenation kinetics observed for total nitrogen
removal, Catalyst II had a hydrodenitrogenation activity
about 1.5 times that of control Catalyst I and about 1.7
times that of control Catalyst III. It also can be seen
from Table 1 that Catalyst II gave about 95% removal of
product sulfur indicating high hydrodesulfurization
activity.
Example V
A series of catalysts was prepared according to the
general procedure of Examples I-III and tested as in
Example IV. Composition of the catalysts and hydrodeni-
trogenation activity based upon both total and basic
nitrogen relative to control Catalyst I (see Example I)
are reported in Table 2. For completeness, relative
activities of Catalyst II and control Catalyst III also
are included in the table. Unless otherwise indicated,
MoO3 content of catalysts was 15 wt.% and phosphorus con-
tent, calculated as the element, was 1.3 wt.%.
Table 2
Catal st Relative Activity
y
Number Composition Total N Basic N
I NoO3/Al2O3
25III MoO3/Al2O3 0.89 0.84
II MoO3-P/A12O3 1.49 1.62
IV MoO3/Al2O3 P 1 0.83 0.71
V ~oO3-P/A12O3-P( ) 0.72 0.61
VI MoO3-P/A12O3( ) 1.34 1.41
30VII MoO3-P/Al2O3( ) 1O71 1.88
(1) The ~upport used in preparation of Catalysts IV and
V was a large-pore alumina containing about 5.0 wt.%
- phosphorus, calculated as the element.
(2) In preparation of Catalyst VI, an alumina support as
in Example I was impregnated with 2.4 gm 85 wt.%
phosphoric acid in 26 ml water, dried and calcined,
_ _
-33-
impregnated with molybclenum heptamol~bdate and dried
and calcined.
(3) Catalyst VII contained 18 wt.% MoO3.
As can be seen from Table 2, Catalysts II, VI and
VII according to the invention were significantly more
active for hydrodenitrogenation than any of the other
catalysts, with Catalysts II and VII, in which molybdenum
and phosphorus component precursors were simultaneousl~
impregnated, being superior to Catalyst VI, in which
phosphorus and molybdenum component precursors were
sequentially impre~nated. Direct comparison of results
with Catalysts IV and V to results with the other cata-
lysts is difficult because the pore structure of the alu-
mina- and phosphorus oxide-containing support of the
former was significantly different from that of the
small-pore alumina used for the other catalysts. How-
ever, comparison of results with Catalyst IV to those
with Catalyst V indicates that the presence of phosphorus
in the support was detrimental to attempted promotion of
hydrogenating metal with phosphorus component.
Example VI
78.6 gra~s of a gamma-alumina extrudate (obtained
from American Cyanamid and identified as SN 469S) having
a 0.079 centimeter average diameter was calcined in an
oven at 500C. for 3 hours. The calcined product had a
BET surface area of 204 m2/gm, a pore volume of 0.77
cc/gm, both as determined ~y nitrogen desorption, an
average pore diameter of 151 A, and the following dis-
tribution of the total pore volume: 22.6% in poreshaving diameters of 50A to 80A, 73.8% in pores having
o O
diameters of 80A to 130A, 42.7% in pores having diame-
ters 80A to lOOA, 31.2% in pores having diameters of
O O
lOOA to 130A, and 2.1% in pores having diameters
greater than 130A. The calcined alumina has the fol-
lowing surface area distribution: 58.9 m2/gm in pores
having diameters of 50A to 80A, 137.4 m2/gm in pores
-34-
O o 2
having diameters of 80A to 130A, 84.g m /gm in pores
having 80A to lOOA, 525.5 m2/gm in pores having diame-
o O "
ters of lOOA to 130A, and 2.2 m'/~n in pores having
diameters greater than 130A.
78.6 grams of this calcined gamma alumina was com-
bined with a solution containing 22.08 grams of ammonium
heptamolybdate (NH4)6 Mo7024~6H20 and 6.12 grams of 85%
phosphoric acid in 50 milliliters of water. The volume
of solution employed was sufficient to fill the pores of
the alumina. The resulting mixture was allowed to stand
at ambient temperature (about 25C) for one hour, then
was dried for one hour at 120C in an oven, and there-
after was calcined in air for one hour at 540C.
The resulting product is designated Catalyst A, and
its metals content, pore volume, pore volume distribu-
tion, surface area, surface area distribution and average
pore diameter are presented in Table 3.
~2~3~
-35-
TABLE 3
Catalyst A B C D
Metals concentration (wt%)
Mo, as MoO3 18 10.3 3.5- 16.3
4.~
Co, as CoO - - ~ 3 4
P, as P 1.6 - - -
Total Pore volume (cc/gm) 0.5424 0.6215 1.15- 0.6528
1.50
% of Pore volume
in pores having diameters
(A) of
50-80 21.4 26.1 14.0
80-130 75.0 61.1 50.0
80-100 44.6 35.3 20.~
100-130 31.4 25.~ 29.1
>130 2.1 9.2 31.6
Total Surface area (m2/gm) 148 184 150- 172
180
Surface area
(m2/gm) i.n pores having
diameters (A) of
50-80 40.5 60.7 - 36.0
80-130 104.2 100.3 - 85.3
80-100 65.2 62.6 - 40.4
100-130 3g 0 37.7 - 44 9
>130 O 1.6 0.55 - 27.7
Average pore diameter (A) 94 92 >200 110
Examples VII-XI
Various combinations of Catalysts A, B, C and D were
employed in a two-reactor system for the demetallation
and desulfurization of a resid feed. Each of Catalysts
B, C and D was a metal-impregnated gamma-alumina extru-
date obtained from American Cyanamid and having a O.079
centimeter average diameter. The metals content, pore
volume 9 pore volume distribution, surface area, surface
area distribution and average pore diameter of each of
~L3~3~7G
-36-
Catalysts B, C and D are also presented in Table 3.
Catalyst D is marketed as Amocat lA.
Each reactor was 81 centimeters long and had an
inside diameter of 0.95 centimeter. In operation, the
feed flowed upwardly through the first or upstream
reactor and the effluent from the first reactor then
flowed upwardly through the second or downstream reactor.
In Examples VII and VIII, the upstream reactor was loaded
with a uniform mixture of 10 cubic centimeters of Cata-
lyst C and 10 cubic centimeters of 10/14 mesh porous
alpha-alumina diluent, and the downstream reactor was
loaded with a uniform mixture of 20 cubic centimeters of
Catalyst B and 20 cubic centimeters of 10/14 mesh porous
alpha-alumina diluent.
In Example 9, the upstream reactor was loaded with a
uniform mixture of 10 cubic centimeters of Catalyst C and
10 cubic centimeters of 10/14 mesh alpha-alumina diluent,
and the downstream reactor was loaded with a uniform mix-
ture of 20 cubic centimeters of Catalyst A and 20 cubic
centimeters of 10/14 mesh, alpha-alumina diluent. In
Example 10, the upstream reactGr was loaded with a uni-
form mixture of 10 cubic centimeters of Catalyst D and 20
cubic centimeters of 10/14 mesh vermiculite diluent, and
the downstream reactor was loaded with a uniform mixture
of 20 cubic centimeters of Catalyst A and 20 cubic cen-
timeters Qf 10/14 mesh vermiculite diluent. In Example
11, the upstream reactor was loaded with a uniform mix-
ture of 10 cubic centimeters of Catalyst D and 20 cubic
centimeters of 10/14 mesh alpha-alumina diluent, and the
downstrearn reactor was loaded with a uniform mixture of
20 cubic centimeters of Catalyst A and 20 cubic centime-
ters of 1~/14 mesh alpha-alumina diluent.
The feed used in Examples VII-XI was a vacuum resid,
an atmospheric resid or a blend of these resids. The
feed characteristics are presented in Table 4.
~3~
-37-
Table 4
Feed Composition (Wt. %) Feed 1 Feed 2
Nickel (p.p.m.) 52 10
Vanadium (p.p.m.) 228 4~2
Sulfur 3.91 3.70
Nitrogen 0.478 0.62
Carbon 84.72 84.66
Hydrogen 10.35 10.38
<538C 8.6 43.7
Ramscarbon 21.0 13.42
Asphaltenes 12.6 7.5
Toluene insolubles 1.0~ 0.14
API Gravity () 6.6 9.~
To start a run, both upstream and downstream reac-
tors were filled with gas oil and pressured to 13.8 MPawith hydrogen. The temperature of each reactor was then
raised to 149C. for at least one hour and then was
raised to the desired reaction temperature. Using a
positive displacement Ruska pump, resid feed was then
introduced to the upstream reactor, from which the
effluent then passed into the downstream reactor. The
feed rate in each reactor was from about 0.2 to about l.0
volume per hour per volume of catalyst, in terms of space
velocity. Each of Examples VII-XI was conducted for 14
to 61 days, with daily sampling and analysis of the
liquid product recovered using a high pressure separator.
The cGnditions employed in Examples VII-XI are shown
in Table 5. The reaction temperature, space velocity or
identity of the feed employed in Examples IX-XI were
varied durin~ the course of the run. Consequen~ly, in
Table 5, the reaction temperature, space velocity and
identity of the feed are listed for each stage of th~
runs where one of them is changed. The feed rate pre
sented in Table 5 is the overall space velocity based on
combined volume of catalysts in the ups~ream and down
stream reactors. The higher metals content o~ Feed 2 was
employed, and generally at higher space velocities, to
13~
-3~-
accelerate the substantial deposition of metal
contaminants on the catalyst, under which condition,
prior art catalysts are known to deactivate.
The results obtained for the liquid product sampled
at one day during the run in each of Examples VIII and XI
and the results obtained for the liquid products sampled
at two days during the run in each of Examples VII, IX,
and X are presented in Table 6. The API gravities, com-
bined nickel and vanadium contents and solids contents of
all of the liquid products sampled during Example IX are
presented in FIGS. 1-3, respectively.
~0
3~
-39-
Table 5
Example No. VII VIII IX X XI
Days 1-23 1-14 1-9 1-7 1-16
Feed 1 1 1 1 2
Feed Rate ~v/v/hr) 0.2 0.2 0.2 0.2 1.0
Temperature (C) 416 405 405 416 ~l16
Hydrogen Addition
Rate (m3/m3) 1600 1600 1600 1600 900
Days 10--34 8-20 17-31
Feed 1+2 2
Feed Rate (v/v/hr) 0.2 1.0 0.2
Temperature (C) 416 416 416
Hydrogen Addition
Rate (m3/m3) 1600 900 1600
Days 35-56 21-28
Feed
Feed Rate (v/v/hr) 0.2 0.2
Temperature (C) 416 416
Hydrogen Addition
Rate (m3/m3) 1600 1600
Days 57-61
Feed
Feed Rate (v/v/hr) 0.2
Temperature (C) 418
Hydrogen Addition
Rate (m3/m3) 1600
3~
-40-
Table 6
Exam~e 7 ~Example 8 Example 9
Day 15 23 8 9 52
Metal Content 3.0 4.5 1.24 2.1 17.8
of Catalyst (Wt.%)
H2 Consumption 267 255 187 225 209
(m /m )
10 Liquid Product
Properties
Content (Wt.%)
Nickel (ppm) 14 12 3 2 8
Vanadium (ppm) 3 6 <2 2 4
Sulfur 0.43 0.47 0 80 0.24 0.64
Nitrogen 0.25 0.22 0.32 0.29 0.25
Carbon 85.95 86.99 87.11 87.15 86.38
Hydrogen 11.90 11.89 11.63 11.98 1.1.73
<538C. 83.Oa 75.5b 68.Oa 74 5b 65 3b
Asphaltenes 1.2 1.54 l.S 2.3 0.7
Ramscarbon 4.10 4.84 6.77 7.25 5.72
Cl - C4 4.77 5.02 2.09 1.62 2.26
Toluene 0.62 0.49 ND ND 0.86
Insolubles
API Gravity () 25.1 24.0 20.8 19.5 22.8
Footnotes
a Determined by gas chromatographic simulated distillation
b Determined by distillation
c Value for the 22nd day
.,
~f~3~6
-41-
Table 6 (continued~
Example 10 Example-ll
Day 6 25 23
Metal Content 1.1 20.2 22
of Catalyst (Wt.%)
H2 Consumption
(m /m 3 242 ND ND
10 Liquid Product
Properties
Content (Wt.%)
Nickel (ppm) ~2 16 8
Vanadium (pp~) <2 37 9
Sulfur 0.220.53 0.49
Nitrogen 0.15 ND 0.18
Carbon 87.10 ND ND
Hydrogen 12.06 ND ND
<538C. ~ 89 4b88 ob
20 Asphaltenes 0,26 ND ND
Ramscarbon 2.072.47 3.72
Cl - C4 2.16 ND ND
Toluene 0.230.53 0.98
Insolubles
API Gravity () 27.6 27.0 25,3c
Footnotes
a Determined by gas chromatographic simulated distillation
b Determined by distillation
c Value for the 22nd day
-42-
The results in Table 6 and the plots in FIGS. 1-3
illustrate that the activity of the catalyst of this
invention in the desulfurization stage is maintained even
after a very substantial buildup of metals on the cata-
lyst. With a conventional catalyst employed in thedesulfurization stage in Example VII, the reactor system
plugged at the end of the 23rd day of the run as a result
of excessive solids formation. By contrast, when a cata-
lyst of the present invention was employed in the de~ul-
furization stage in Example IX, the level of solids inthe liquid product was only up to about 1 wt.% even when
the buildup of metals on the catalyst was in excess of 20
wt.% of the catalyst, and the reactor system was operable
throughout the 61 day run. Furthermore, the conversion
to product boiling below 538C was at substantially the
same level in Example IX at the 9th day of the run and at
a reaction temperature of only 405C as in Example VII at
the 23rd day of the run and at the higher reaction tem-
perature of 416C.
From the above description it is apparent that the
objects of the present invention have been achieved.
While only certain embodiments have been set forth,
alternative embodiments and various modifications will be
apparent from the above description to those skilled in
the art. These and other alternatives are considered
equivalen~s and are within the spirit and scope of the
present invention.
