Note: Descriptions are shown in the official language in which they were submitted.
This invention relates to hydrotreating, and more
particularly, to an improved hydrotreating catalyst and process
using the catalyst.
In the hydrotreating of hydrocarbon containiny feed-
stock, such hydrotreating is generally accomplished in the presence
of a hydrotreating catalyst comprised of Group VI and Group VIII
metals supported on a suitable support. There is a continued
need for improvements in such catalysts so as to provide improved
activity and longer catalyst life.
In accordance with one aspect of the present invention,
there is provided an improved hydrotreating catalyst which is
comprised of catalytically effective amounts of nickel and
molybdenum supported on alumina wherein the catalyst has a total
porosity of at least 0.5 cc/g and most generally from 0.75 to O.9S
cc/g, a pore size distribution as defined in the following Table
and wherein the catalyst has been calcined at a temperature of
from 1150 F to 1300 F.
TABLE
Pore Diameter, A Porosity (cc/g)
. _ _
~250 0.25 - 0.40
250 - 500 0.10 - 0.25
500 - 1500 0.20 - 0.30
1500 - 4000 0.05 - 0.15
~400Q 0.03 - 0.10
The inventor has found that such catalyst has improved
hydrotreating activity and improved catalyst life, provided that
the catalyst is calcined at such temperatures. The inventor
has found that calcining of such catalyst at temperatures
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.~ ~. . ..
o~
normally used for the calcining of supported nickel-
containing catalysts (about 1000 - 1050F) does not provide
a useable catalyst for the hydrotreating of higher boiling
feedstocks in that severe coking of the catalyst occurs after
only a short period of operation.
The catalyst of the invention is comprised of
nickel and molybdenum and may further include cobalt.
The catalyst of the invention generally contains
from 1% to 6%, preferably from 1% to 4% of nickel; and from
5% to 16%, preferably from 6% to 10% of molybdenum, and
0% to 6% of cobalt, all by weight. If cobalt is employed,
the cobalt is generally present in an amount of from 1%
to 6~, by weight.
The particle size of the catalyst of the invention
is generally in the order of from 0.005 to 0.125 inch, with
the catalyst, if in extruded form, generally having a size
in the order of from O.OlS to 0.125 inch, and, if in spherical
form, a size in the order of from 0.005 to 0.125 inch.
In general, the surface area of the catalyst is
at least 125 m2/G, and most generally from 150 - 300 m /g.
The alumina of the catalyst is generally the gamma form
thereof. In some cases, the alumina support could include
up to 10% of silica.
The nickel and molybdenum and optionally also
cobalt are supported on the alumina by procedures generally
known in the art. Thus, for example, a molybdenum compound,
such as ammonium molybdate may be added to an aqueous slurry
of the alumina having a porosity and pore size distribution
90~
to provide a finished catalyst having the hereinabove defined
porosity and pore size distribution, followed by spray drying
and formation, for example, into spheres. Optionally the
supported molybdenum may be calcined at this time; however,
such calcining would be additional to and not in lieu of
the final calcination in accordance with the invention.
The molybdenum supported on the alumina is then impregnated
with nickel, for example as aqueous nickel nitra-te, and
optionally also cobalt, followed by drying.
The supported catalyst is then calcined in accordance
with the invention at a temperature of from 1150F to 1300F,`
preferably at a temperature of from 1150F to 1250F, with the
calcination temperature in most cases being about 1200F.
As hereinabove notea the use of lower calcination temperatures,
as conventionally employed for suppor~ted catalysts containing
nlckel, does not provide an acceptable catalyst (excessive
coke lay-down), and temperatures above 1300F would not be
suitable because of molybdenum volatility. In using the higher
portions of the disclosed calcining temperatures there may
be some deactivation of the nickel component of the catalyst,
and as a result, in most cases the calcination temperature
should not exceed 1250F.
In accordance with anothe~r aspect of the present
invention, the hereinabove described hydrotreating catalyst
is employed for hydrotreating of hydrocarbon-containing feed~
stocks which contain heavier (higher boiling components), with
such feedstocks generally being characterized by having at
least 50~ of components boiling above 975F.
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~lS~ 9
Such feedstocks are generally derived from either petroleum
or coal sources, and as representative examples of such feed-
stocks, there may be mentioned: heavy petroleum crudes, petro-
leu~ rPsidues from atmospheric or vacuum distillatibns, shale
oil, shale oil residues, tar sands, bitumen, coal tar pitches,
solvent refined coal, solvent deasphalted oils, etc~
The hydrotreating of the feedstock is accomplished
at conditions which are generally known in the art to be effec-
tive for upgrading of the feedstock. The catalyst is preferably
presulfided. In qeneral, the hydrotreating is accomplished at
temperatures of the order of from 700 to 900~, preferably
from 750 to 850F, and at pressures of the order of from
1000 to 3500 psig, preferably from 1500 to 3000 psig The
liquid hourly space velocity is generally of the order of from
0.05 to 2.0 hr, preferably 0.1 to 1.0 hr 1 The hydrogen is
supplied in an amount sufficient to accomplish the hydrotreat-
ing, with such hydrogen generally being employed in an amount
of from 2000 to 6000 SCF/bbl. preferably from 4000 to 5000
SCF/b~l.
The hydrotreating may be effected in any one o~ a wide
variety of reactors. Thus, for example, such hydrotreating may
be effected in a fixed bed reactor, a moving bed reactor, a
fluidized bed reactor, an expanded bed reactor, etc., which may
contain one or more beds of the catalyst.
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As known in the art such hydrotreating upgrades the feed-
s~ock by conversion of higher boiling cornponents to lower boiling
S ~ components. In addition, desulfurization and/or denitrogenation
is also accomplished.
The invantion will be fur~her described with respect to
the ~ollowing example:
EXAMPLE.
_
A catalyst was prepared which w~scomprised of 12.0~
Moo3; 1.5~ CoV and 1.5% NiO supported on gamma-alumina having
a total porosity of 0.87-0.89 cc/g and a pore size distribution
as follows:
Pore Diameter, A Porosity cc/~
~ 250 0.34 - 0.36
250 - 500 0.19 - 0~15
_ 500 - 1500 0.22 - 0.23
1500 - 4000 0.10 - 0.11
~4000 0.04 - 0.07
The catalystwas in the form of sphercs having a diameter
of the order of .015-.035 inch.
In one case ~case A) the catalyst was calcined at 1050F
and in the other case (case B) the catalyst wa~ calcined in
accordance with the inventionat 1200F.
'!
,
Each of the catalysts was presulfided in the reactor
and tested or the hydrotreating of Cold ~ake Atmospheric
and at
Residue,as an ebullated catalyst bed,at 730~ 7~~hydrogen pres-
~ure o~ 2000 psig, with hydrogen being used at a rate of 5000
S SCF/bbl of feed.
The case A catalyst coked up wi~hin 24 hours.
The case B cataly~t in accordance with the invention
operated for 35 days with the temperature eventually being
raised to 8~0F. The conversion rate was of the order of ~0~,
based on the 975F+ components of the feed.
_ Thus, in accordance with the present invention, ther~
is provided an effective hydrotreating catalyst for upgrading
of heavier hydrocarbon feedstocks. The catalyst is capable of
operating over long perio~ of time and ~t conversion rates of
40~ and greater, in most cases in excess of 50~ and of the order
of 60~, based on the 975F~ components of the feed.
