U.S. patent application number 11/069425 was filed with the patent office on 2005-09-08 for catalyst carrier and catalyst composition, processes for their preparation and their use.
Invention is credited to Creyghton, Edward Julius, Huve, Laurent Georges, Ouwehand, Cornelis, Van Veen, Johannes Anthonius Robert.
Application Number | 20050197249 11/069425 |
Document ID | / |
Family ID | 34896131 |
Filed Date | 2005-09-08 |
United States Patent
Application |
20050197249 |
Kind Code |
A1 |
Creyghton, Edward Julius ;
et al. |
September 8, 2005 |
Catalyst carrier and catalyst composition, processes for their
preparation and their use
Abstract
The invention provides a shaped catalyst carrier which is an
inorganic refractory oxide having a monomodal mercury pore volume
distribution wherein at least 50% of the total pore volume is
present in pores having a pore diameter in the range of from 4 to
50 nm, a catalyst incorporating said carrier and having a high
metals content. The catalyst finds use in hydrocracking refinery
feedstocks.
Inventors: |
Creyghton, Edward Julius;
(Amsterdam, NL) ; Huve, Laurent Georges;
(Amsterdam, NL) ; Van Veen, Johannes Anthonius
Robert; (Amsterdam, NL) ; Ouwehand, Cornelis;
(Amsterdam, NL) |
Correspondence
Address: |
SHELL OIL COMPANY
P O BOX 2463
HOUSTON
TX
772522463
|
Family ID: |
34896131 |
Appl. No.: |
11/069425 |
Filed: |
March 1, 2005 |
Current U.S.
Class: |
502/439 ;
208/108; 208/112 |
Current CPC
Class: |
B01J 35/1038 20130101;
B01J 37/0018 20130101; C10G 47/20 20130101; B01J 37/0203 20130101;
B01J 35/10 20130101; B01J 35/1042 20130101; B01J 29/084 20130101;
B01J 23/888 20130101; B01J 35/1061 20130101 |
Class at
Publication: |
502/439 ;
208/108; 208/112 |
International
Class: |
C10G 047/12 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 3, 2004 |
EP |
04251241.8 |
Claims
That which is claimed is:
1. A shaped catalyst carrier which comprises at least one inorganic
refractory oxide, which carrier has a monomodal pore size
distribution wherein at least 50% of the total pore volume is
present in pores having a diameter in the range of from 4 to 50 nm
and wherein the pore volume present in said pores is at least 0.4
ml/g, all as measured by mercury intrusion porosimetry.
2. A catalyst carrier as claimed in claim 1, wherein the pore
volume present in pores of diameter from 4 to 50 nm is at least 0.5
ml/g.
3. A catalyst carrier as claimed in claim 2, wherein at least 60%
of the total pore volume is present in pores having a diameter in
the range of from 4 to 50 nm.
4. A catalyst carrier as claimed in claim 3, which comprises an
amorphous silica-alumina material or a crystalline aluminosilicate
faujasite material.
5. A catalyst carrier as claimed in claim 4, wherein the compacted
bulk density is in the range of from 0.35 to 0.50 g/ml.
6. A process for the preparation of a catalyst carrier, said
process comprises shaping a mix comprising said at least one
refractory oxide wherein the mix has an LOI in the range of from 55
to 75%.
7. A process as claimed in claim 6, wherein the shaping is by
extrusion.
8. A process as claimed in claim 7, wherein the mix is an extrusion
mix which has a pH in the range of from 3.5 to 7.0.
9. A process as claimed in claim 8, wherein the LOI is in the range
of from 58% to 75% and the pH is in the range of from 3.5 to
5.0.
10. A process as claimed in claim 9, wherein acid is added to the
extrusion mix to adjust the pH, which acid is selected from the
group consisting of acetic acid and nitric acid.
11. A carrier obtainable by a process as claimed in claim 10.
12. A catalyst composition which comprises a carrier as claimed in
claim 1, and at least one hydrogenation metal component selected
from Group VIb and Group VIII metals.
13. A catalyst composition as claimed in claim 12, wherein the
Group VIb metal is tungsten present in an amount in the range of
from 20 to 27 wt %, calculated as the trioxide and based on total
weight of catalyst, and the Group VIII metal is nickel present in
an amount in the range of from 4 to 6 wt %, calculated as the oxide
and based on total weight of catalyst.
14. A process for the preparation of a catalyst composition which
said process comprises calcining a carrier as claimed in claim 1;
and depositing at least one hydrogenation metal selected from the
group consisting of Group VIb and Group VIII in the appropriate
amount, wherein the deposition is effected by an impregnation
solution containing an organic compound having at least two
moieties selected from carboxyl, carbonyl, and hydroxyl.
15. A process as claimed in claim 14, wherein the organic compound
is an organic acid selected from the group consisting of citric
acid, tartaric acid, oxalic acid, malonic acid and malic acid.
16. A catalyst composition obtainable by the process as claimed in
claim 15.
17. A hydrocracking process which comprises contacting a
hydrocarbonaceous feed with a catalyst composition as claimed in
claim 12 at elevated temperature and pressure.
18. A catalyst composition as claimed in claim 12, wherein the
carrier is essentially free of aluminosilicate zeolite and wherein
the carrier further comprises at least one promoter element
selected from the group consisting of silicon and boron.
Description
[0001] This application claims priority to European patent
application no. 04251241.8, filed Mar. 3, 2004.
[0002] The present invention concerns a catalyst carrier suitable
for a hydrocracking catalyst, a catalyst composition incorporating
said carrier, the preparation of both carrier and catalyst
composition and the use of the catalyst composition as a
hydrocracking catalyst.
[0003] Processes that comprise treating crude oil and other
petroleum feedstocks with hydrogen in the presence of a catalyst
are well known. One such process is hydrocracking, in which heavy
distillate hydrocarbons are converted under hydrogen pressure into
products of lower molecular weight in the presence of a catalyst.
Hydrocracking is used in the oil industry to prepare a wide range
of materials, ranging from C3/C4 production to luboil
manufacture.
[0004] Hydrocracking may be operated as either a single or
two-stage process. Two-stage hydrocracking involves a first stage,
which is predominantly a hydrotreatment stage wherein impurities
and unsaturated compounds are hydrogenated in the presence of a
first catalyst having a high hydrogenation function, and a
second-stage where most of the cracking occurs in the presence of a
second catalyst having a strong cracking function. In single-stage
hydrocracking, the treatment and cracking steps occur in one
reactor and may be performed using a single catalyst. The catalysts
employed in hydrocracking are generally made from a carrier
material on which there are deposited catalytically active metals
such as nickel, molybdenum, tungsten, palladium etc.
[0005] The higher the activity of a hydrocracking catalyst the more
efficient a conversion will be. In particular, a more active
catalyst can be operated at a lower temperature than a less active
catalyst to achieve the same degree of conversion. This is
advantageous as a lower operating temperature prolongs catalyst
life and decreases operating costs. Accordingly, there is always a
need for improving catalyst activity. There is also a continuing
need to increase selectivity of catalytic action, particularly to
increase the yield of middle distillate fractions and to reduce the
production of light (C.sub.1-C.sub.4) gaseous materials.
[0006] Prior proposals to improve selectivity and activity have
mainly concentrated on proposing new active materials, such as
modified Y zeolites or silica-alumina materials, or new
formulations comprising several active ingredients to provide a
combined activity and selectivity improvement. Prior art proposals
include US 2002/0160911; WO 00/12213, and WO 2004/047988.
[0007] The present invention provides a shaped catalyst carrier
which comprises at least one inorganic refractory oxide, which
carrier has a monomodal pore size distribution wherein at least 50%
of the total pore volume is present in pores having a diameter in
the range of from 4 to 50 nm and wherein the pore volume present in
said pores is at least 0.4 ml/g, all as measured by mercury
intrusion porosimetry.
[0008] The inorganic refractory oxide material may be any
conventional oxide material suitable for hydroconversion processes.
These are suitably selected from alumina, silica, silica-alumina or
a mixture of two or more thereof. However it is also possible to
use zirconia, clays, aluminium phosphate, magnesia, titania,
silica-zirconia and silica-boria, though these are not often used
in the art. The oxide material maybe amorphous or crystalline, or a
mixture of two or more such materials. Crystalline aluminosilicates
are suitably zeolitic materials; faujasite zeolites, such as
zeolite Y materials are very suitable.
[0009] Preferred refractory oxides are those having a hydrocracking
capability, and may be selected from amorphous silica-alumina and
ultrastable zeolite Y oxidic materials.
[0010] The term "amorphous" indicates a lack of crystal structure,
as defined by X-ray diffraction, in the carrier material, although
some short range ordering may be present. Amorphous silica-alumina
suitable for use in preparing the catalyst carrier is available
commercially. Conventional homogeneous amorphous silica alumina
materials can be used, as can the heterogeneous dispersions of
finely divided silica alumina in an alumina matrix, as described in
U.S. Pat. Nos. 4,097,365 and 4,419,271. Alternatively, the
silica-alumina may be prepared by a co-gelation process or a
grafting process, as are well known in the art. The amorphous
silica-alumina preferably contains silica in an amount in the range
of from 25 to 95% by weight as calculated on the carrier alone
(i.e. based on total carrier). More preferably the amount of silica
in the carrier is greater than 35% wt, and most preferably at least
40% wt. A very suitable amorphous silica-alumina product for use in
preparing the catalyst carrier of the invention comprises 45% by
weight silica and 55% by weight alumina and is commercially
available (ex. Criterion Catalysts and Technologies, USA).
[0011] Preferred zeolitic Y materials are an ultrastable zeolite Y
(USY) or a very ultrastable zeolite Y (VUSY) of unit cell size
(a.sub.o) less than 2.440 nm (24.40 .ANG.ngstroms), in particular
less than 2.435 nm (24.35 .ANG.ngstroms) and a silica to alumina
ratio of from 4 or more, for example from 4 to 100. Suitable
zeolite Y materials are known, for example, from European Patent
Specifications Nos. 247 678 and 247 679, and WO 2004/047988.
[0012] Whilst USY and VUSY Y zeolites are the preferred form of
cracking component used in the present invention, other Y zeolite
forms are also suitable for use, for example the known
ultrahydrophobic Y zeolites.
[0013] Preferred VUSY zeolite of EP-A-247 678 or EP-A-247 679 is
characterised by a unit cell size below 2.445 nm (24.45
.ANG.ngstroms) or 2.435 nm (24.35 .ANG.ngstroms), a water
adsorption capacity (at 25.degree. C. and a p/p.sub.o value of 0.2)
of at least 8% w of the zeolite and a pore volume of at least 0.25
ml/g wherein between 10% and 60% of the total pore volume is made
up of pores having a diameter of at least 8 nm.
[0014] Most preferred are the low unit cell size, high surface area
zeolite Y materials described in WO 2004/047988 and US 2004/0152587
which are incorporated herein by reference. Such materials can be
described as a zeolite of the faujasite structure having a unit
cell size in the range of from 24.10 to 24.40 .ANG., a bulk silica
to alumina ratio (SAR) above 12, and a surface area of at least 850
m.sup.2/g as measured by the BET method and ATSM D 4365-95 with
nitrogen adsorption at a p/po value of 0.03. Said materials are
prepared by a process which comprises
[0015] a) providing a starting zeolite of the faujasite structure
having a silica to alumina ratio of from 4.5 to 6.5 and an alkali
level of less than 1.5% wt;
[0016] b) hydrothermally treating said starting zeolite at a
temperature in the range of from 600 to 850.degree. C., preferably
600 to 700.degree. C. more preferably 620 to 680.degree. C. and
especially 630 to 670.degree. C., and at a partial pressure of,
preferably externally supplied, steam in the range of from 0.2 to 1
atmosphere for a time effective to produce a intermediate zeolite
having a unit cell size of from 24.30 to 24.45 .ANG., being
suitably in the range of from 0.5 to 5 hours, more suitably 1 to 3
hours;
[0017] c) contacting the intermediate zeolite with an acidified
solution comprising an acid and optionally an ammonium salt under
conditions effective to produce a high surface area zeolite having
a unit cell size in the range of from 24.10 to 24.40 .ANG., a molar
silica to alumina ratio of greater than 12 and a surface area of
greater than 850 m.sup.2/g, thereby producing the high surface area
zeolite; and
[0018] d) recovering said high surface area zeolite.
[0019] Especially preferred high surface area materials have one or
more of the following features:
[0020] unit cell size in the range of from 24.14 to 24.38,
preferably from 24.24, more preferably from 24.30, to 24.38,
preferably to 24.36, especially to 24.35 .ANG., and maybe for
example in the range of from 24.14 to 24.33 .ANG.;
[0021] a SAR in the range of from 20 to 100, preferably from 20 to
80, especially to 50;
[0022] surface area of at least 875, preferably at least 890, for
example at least 910 m.sup.2/g;
[0023] a micropore volume,as determined by nitrogen porosimetry
using the t-plot method, also known as the t-method, using nitrogen
as the adsorbate as described by Lippens, Linsen and de Boer,
Journal of Catalysis, 3-32,(1964), of greater than 0.28 ml/g,
suitably greater than 0.30 ml/g. Generally micropore volume will be
less than 0.40 ml/g, suitably less than 0.35 ml/g. Herein
micropores are pores having a diameter of less than 2 nm.
[0024] Mercury intrusion porosimetry is a standard technique to
determine particularly mesoporosity and macroporosity of a
refractory oxide or other solid porous materials since it can
determine pore volume distributions of 4 nm and above. Mesopores
herein are pores having a diameter in the range of from 4 to 50 nm;
macropores herein are pores having a diameter above 50 nm. It is
the aim of the present invention to maximise the mesoporosity and
minimise the macroporosity of the carrier, and at least to increase
the number of mesopores without increasing the number of macropores
in the carriers.
[0025] The shaped carrier of the invention has a monomodal
distribution. This means that in a conventional pore size
distribution (PSD) graph which shows dD plotted against dV/dD there
is a single peak, suitably a single sharp peak, which in the case
of the carrier of the invention lies in the mesopore range: pores
of diameter in the range of from 4 to 50 nm. Herein D indicates
pore diameter and V indicates pore volume. It is possible in
carriers of the invention that a rounded or bell shaped curve could
also exist in the macropore range of such a PSD graph; this is not
a peak within the meaning of the present text.
[0026] Preferably the mesopore pore volume is at least 0.45 ml/g,
preferably at least 0.5 ml/g. Preferably the mesopore pore volume
is at most 0.8 m/g, more preferably at most 0.7 ml/g. The nature of
the inorganic refractory oxide can influence the most preferred
mesopore pore volumes for the shaped carrier of the invention.
Where the refractory oxide is wholly or predominantly amorphous in
nature, for example an alumina, silica or amorphous silica-alumina
material, then the mesopore pore volume is most suitably in the
range of from 0.5 to 0.8 ml/g, preferably 0.6 to 0.75 ml/g, and
more preferably 0.65 to 0.70 ml/g. Where the refractory oxide
material comprises or contains a crystalline material, for example
an aluminosilicate zeolite, particularly a zeolite Y material, then
the mesopore pore volume is most suitably in the range of from 0.4
to 0.6 ml/g, preferably 0.45 to 0.6 ml/g, more preferably 0.5 to
0.6 ml/g.
[0027] Preferably the proportion of the pore volume that is in the
mesopores is at least 60% and at most 90%. Again the nature of the
refractory oxide material can influence the most preferred
proportions. Where the refractory oxide material is wholly or
predominantly an amorphous material, as above, then most suitably
the proportion of the pore volume in the mesopores is in the range
of from 75 to 90%, preferably 80 to 90%, and more preferably 85 to
90%. Where the refractory oxide material comprises or contains a
crystalline material, as above, then most suitably the proportion
of the pore volume in the mesopores is in the range of from 50 to
75%, preferably from 60 to 75%.
[0028] The effect of this high mesopore pore volume is that the
compacted bulk density (CBD) of the catalyst carrier becomes
greatly reduced. Reduction of the CBD can generally be desirable
since it means that a reduced amount of expensive catalyst is
required. There are various ways to reduce compacted bulk density,
but other means do not result in an increased activity or middle
distillate selectivity. By the use of a catalyst carrier of the
invention the CBD of the final catalyst is lowered allowing a more
economical catalyst refill for the refiner, but also surprisingly
the activity of the catalyst is increased alongside an increased
middle distillate selectivity and aromatics hydrogenation. This is
particularly seen with the preferred zeolitic materials for use in
the catalysts of the present invention: the high surface area
zeolite Y materials described herein.
[0029] A further advantage of the catalyst carrier of the invention
is that this increased activity of the final catalyst is maintained
over time, and thus the stability of the catalyst is greatly
enhanced. This is particularly seen with catalyst carriers made
wholly or predominantly, for example from 95 to 100 wt %, of
amorphous refractory oxide materials.
[0030] A yet further advantage of the shaped catalyst carrier of
the invention is that the carrier when in extrudate form exhibits
an increased strength and attrition resistance, and thus enables a
longer catalyst lifetime in use.
[0031] The CBD of the carrier of the invention is suitably in the
range of from 0.35 to 0.50 g/ml, preferably 0.35 to 0.45 g/ml, more
preferably 0.38 to 0.43 g/ml.
[0032] In forming a catalyst carrier of the present invention, the
refractory oxide material(s) may be usefully mixed with an
amorphous binder component. The amorphous binder component may be
any other refractory inorganic oxide or mixture of oxides
conventional for such compositions. Generally this is an oxidic
material not having a cracking capability and may be selected from,
for example, alumina, silica, or a mixture thereof, alumina being
preferred, but may also be a silica-alumina material, containing in
the range of from 5 to 95% w silica, most suitably amorphous silica
alumina materials hereinbefore mentioned. However again it is also
possible to use zirconia, clays, aluminium phosphate, magnesia,
titania, silica-zirconia and silica-boria, though these are not
often used in the art. The amount of binder is generally in the
range of from 0 to 70 wt % and is suitably less than 50 wt %, and
may be less than 30 wt %. However where a zeolite is present in the
carrier, the amount of zeolite in the catalyst support when binder
is also present may be up to 90% by weight, but is preferably in
the range of from 2, more preferably 10, especially 20, to 80% by
weight, based on the total catalyst support, with the balance being
binder.
[0033] It is possible, and may be preferred in certain cases, for
the catalyst carrier, and thus the catalyst composition, of the
present invention, also to include a second cracking component.
This is preferably a second zeolite. Most preferably a second
zeolite is selected from zeolite beta, zeolite ZSM-5, or a zeolite
Y of different unit cell size. Where a second zeolite Y is used,
preferably it has a unit cell size greater than 24.40 .ANG.. A
second cracking component may be present in an amount up to 20
parts by weight, based on total zeolite plus binder, but preferably
is present in an amount in the range of from 0.5 to 10 parts by
weight.
[0034] It should be noted that amorphous silica alumina may act
both as a second cracking component and as a binder. As a cracking
component it is most usefully employed in high operating
temperature processes; as a binder it has been found useful in
protecting a zeolite from loss of crystallinity, and therefore from
deactivation, in use in any process that water and/or fluoride is
present or generated.
[0035] The shaped carrier may be prepared by any conventional way
of compressing the refractory oxides into a shaped form. It is a
routine measure to check the mesporosity of the resulting materials
once prepared. Compression may be via pelletization, extrusion or
other compression means common in the art. We have found that the
mesoporous shaped carrier of the present invention may be prepared
more consistently if the oxides are prepared from a mix having a
selected LOI (loss on ignition). Additional consistency of material
is obtained if the mix has a selected pH range.
[0036] The present invention provides a process for the preparation
of the shaped catalyst carrier of the invention, which comprises
shaping a mix comprising said at least one refractory oxide wherein
the mix has an LOI in the range of from 55 to 65%.
[0037] Herein loss on ignition (LOI) for a material is the relative
amount of lost mass upon heating the material, i.e. the water
content. Unless otherwise specified herein, this is determined
herein by heating the material to 540.degree. C. under the
following procedure: a sample is mixed well to prevent any
inhomogeneity. The weighed sample is transferred into a weighed and
precalcined crucible. The crucible is place to a preheated oven at
540.degree. C. for a minimum time of 15 minutes, but typically for
1 hour. The crucible containing the dried sample is weighed again,
and the LOI is determined according to the formula:
LOI%=(w-w.sub.calc)/w*100%
[0038] where w is the original weight of the sample, w.sub.calc is
the weight of the calcined sample after heating in the oven, both
corrected with the weight of the crucible.
[0039] The mix may be formed of the refractory oxide materials and
additional components, eg binder, with an aqueous liquid, most
suitably water. The oxidic and binder materials are usually used in
powder or crystal form. Shaping is most suitably and preferably by
extrusion.
[0040] Conventionally extrusion mixes have an LOI determined by the
need to combine particulate materials into a form which can be
forced as a combined homogeneous entity through an extrusion die
wherein the shear forces and generated heat cause fusion of the
component materials into a shaped product which will maintain its
integrity over time and in use, i.e. maintain mechanical strength.
An extrusion mix is conventionally formed as a dough-like material
through kneading or mulling with the addition of water. The water
will penetrate the pores of the materials as well as the
interstices between materials. The LOI of an extrusion mix is
therefore different depending on the nature (porosity) of the
materials and size of the particles, and is often in the range of
from 50 to 70%. The process of the present invention generally
requires a higher water content for the mix than would normally or
conventionally be applied for the materials utilised. Thus if a mix
would normally require a 54% LOI, then a higher LOI, eg 58%, will
increase the mesoporosity of the carrier.
[0041] The LOI is most suitably at least 56%, very suitably at
least 57%, preferably at least 58%, more preferably at least 59%,
especially at least or just in excess of 60%. Since LOI can be
assessed to a high accuracy, `in excess` includes for example
60.01%. Most preferably the LOI is in the range of from 60, or just
in excess of 60, to 75%, particularly for carriers in which the
refractory oxide is wholly or predominantly amorphous silica
alumina.
[0042] Preferably the extrusion mix has an acidic pH, i.e. a pH of
7.0 or less. Most preferably the pH is in the range of from 3.5,
suitably 4.0, to 7.0; more preferably 4.0 to 5.0, especially 4.2 to
4.7.
[0043] A suitable combination of LOI and pH conditions are an LOI
of from 58, very suitably 60 or just in excess of 60, to 75%, and a
pH in the range of from 3.5, preferably 4.0, to 5.0.
[0044] Any convenient mono-basic acid may be used to adjust the pH
for the acidic solution; examples are nitric acid and acetic acid.
During extrusion, conventionally extrusion aids may be utilized;
usual extrusion aids include Superfloc, obtainable from Nalco.
[0045] Extrusion may be effected using any conventional,
commercially available extruder. In particular, a screw-type
extruding machine may be used to force the mixture through orifices
in a die plate to yield carrier extrudates of the required form,
e.g. cylindrical or trilobed. The strands formed on extrusion may
then be cut to the appropriate length.
[0046] The form of the carrier extrudates can also affect the
activity of the final catalyst as is known in the art. The form is
very suitably a conventional TRILOBE, twisted trilobe, or
quadrilobe form (Trilobe is a trade mark). The form may usefully be
a shaped trilobe as described in International patent publication
WO 03/013725. Thus it may usefully be an elongate, shaped particle
comprising three protrusions each extending from and attached to a
central position aligned along the central longitudinal axis of the
particle, the cross-section of the particle occupying the area
encompassed by the outer edges of six outer circles around a
central circle minus the area occupied by three alternating outer
circles, wherein each of the six outer circles is touching two
neighbouring outer circles and wherein three alternating outer
circles are equidistant to the central circle, have the same
diameter, and may be attached to the central circle. The three
alternating outer circles preferably have a diameter in the range
of from 0.74 to 1.3 times the diameter of the central circle, and
more preferably have the same diameter as the central circle. Such
particles most usefully have a length to diameter (L/D) ratio of at
least 2, preferably in the range of from 2 to 5, and a length in
the range of from 1 to 25 mm.
[0047] If desired, the carrier extrudates may be dried, e.g. at a
temperature of from 100 to 300.degree. C. for a period of from 30
minutes to 3 hours, prior to calcination.
[0048] Calcination is conveniently carried out in air at a
temperature in the range of from 300 to 850.degree. C., preferably
from 400 to 825.degree. C., for a period of from 30 minutes to 4
hours.
[0049] Specifically for the preparation of the shaped carrier when
the oxide is an amorphous material, especially an amorphous silica
alumina, any of the general carrier preparation techniques known in
the art may be utilised, with the LOI and pH conditions adapted as
above. A preferred method for the preparation of such a carrier
comprises mulling a mixture of the amorphous silica-alumina and a
suitable liquid, extruding the mixture and drying and heating the
resulting extrudates, at a temperature in the range of from 400 to
850.degree. C., as for example described in WO-9410263 but is
preferably from 650.degree. C. to 850.degree. C., more preferably
700.degree. C. to 825.degree. C., especially 750.degree. C. to
810.degree. C. The extrudates may have any suitable form known in
the art, for example cylindrical, hollow cylindrical, multilobed or
twisted multilobed. A preferred shape for the catalyst particles is
multilobed, for example trilobed. Typically, the extrudates have a
nominal diameter of from 0.5 to 5 mm, preferably from 1 to 3 mm.
After extrusion, the extrudates are dried. Drying may be performed
at an elevated temperature, preferably up to 300.degree. C., more
preferably up to 200.degree. C. The period for drying is typically
up to 5 hours, preferably in the range of from 30 minutes to 3
hours. Preferably, the extrudates are then calcined after drying at
very high temperature, as above, typically for a period of up to 5
hours, preferably in the range of from 30 minutes to 4 hours.
[0050] The present invention further provides a catalyst
composition which comprises a carrier of the present invention, and
at least one hydrogenation metal component selected from Group VIb
and Group VIII.
[0051] At least one hydrogenation metal component is incorporated
into the catalyst of the invention. This addition may occur at any
stage during catalyst preparation, using techniques conventional in
the art. For example, the hydrogenation component can be added to
the oxide, or a mixture of oxide and binder, through co-mulling.
However preferably the hydrogenation component is added to the
formed extrudates either before or after optional calcining, using
conventional impregnation techniques, eg as one or more aqueous
impregnating solutions of Group VIB and/or Group VIII metal salts.
If the impregnation occurs after calcination of the formed
extrudates, then a further drying and optional calcination
procedure is usefully employed.
[0052] Herein reference is made to the Periodic Table of Elements
which appears on the inside cover of the CRC Handbook of Chemistry
and Physics (`The Rubber Handbook`), 66.sup.th edition and using
the CAS version notation.
[0053] Suitably the hydrogenation component is selected from
nickel, cobalt, molybdenum, tungsten, platinum and palladium.
[0054] Examples of hydrogenation components that may thus suitably
be used include Group VIB (e.g. molybdenum and tungsten) and Group
VIII metals (e.g. cobalt, nickel, iridium, platinum and palladium),
their oxides and sulphides. The catalyst composition will
preferably contain at least two hydrogenation components, e.g. a
molybdenum and/or tungsten component in combination with a cobalt
and/or nickel component. Particularly preferred combinations are
nickel/tungsten and nickel/molybdenum. Very advantageous results
are obtained when these metal combinations are used in the sulphide
form.
[0055] The present catalyst composition may contain up to 50 parts
by weight of hydrogenation component, calculated as metal per 100
parts by weight (dry weight) of total catalyst composition. For
example, the catalyst composition may contain from 2 to 40, more
preferably from 5 to 30 and especially from 10 to 20, parts by
weight of Group VIB metal(s) and/or from 0.05 to 10, more
preferably from 0.5 to 8 and advantageously from 1 to 6, parts by
weight of Group VIII metal(s), calculated as metal per 100 parts by
weight (dry weight) of total catalyst composition.
[0056] Particularly where the oxide is amorphous and especially
amorphous silica alumina, the amount of Group VIII metal and Group
VIB metal in the catalyst may vary depending on the metal type and
the intended purpose of the catalyst, however, the amount of Group
VIII metal will preferably be in the range of from 0.5 to 10% wt,
whilst the amount of Group VIB metal will preferably be in the
range of from 3 to 30% wt, measured as the metal, based on total
weight of catalyst. A preferred catalyst according to the present
invention, comprises nickel in an amount in the range of from 1 to
6% wt, more preferably 3 to 5% wt; and molybdenum in an amount in
the range of from 6 to 18% wt, preferably 10 to 15% wt, or tungsten
in an amount in the range of from 10 to 25% wt, preferably 15 to
22% wt.
[0057] As previously noted the Group VIII and Group VIB metals may
be deposited on the carrier using any of the suitable methods known
in the art, for example by ion exchange, competitive ion exchange
or impregnation. Conveniently, the metals may be deposited by
impregnating the carrier with an impregnation solution comprising
appropriate metal-containing compounds, and optionally a chelating
agent such as ethylene glycols, ethylene diamine, tartaric acid,
malonic acid, citric acid, malic acid, nitriloacetic acid or
ethylenediaminetetraacetic acid(EDTA). After impregnation, the
catalyst is preferably dried at a temperature of up to 200 .degree.
C., then heated or calcined at a temperature in the range of from
200 to 600.degree. C.
[0058] It has been found that the mesoporous carrier of the present
invention permits a higher metals incorporation with a greater
metal accessibility as well as a lower CBD for the resulting
catalyst. This in turn permits a higher hydrogenation activity such
that not only is an increased aromatics hydrogenation obtained but
also desulphurisation can be given. This means that to achieve
current low sulphur requirements for fuels, it would not be
necessary to apply a further treatment with a desulphurisation
catalyst.
[0059] In addition to the carrier of the invention possessing a
uniquely low compacted bulk density (CBD), the catalyst composition
of the invention has a CBD of at most 0.70, preferably at most
0.68, ml/g. The CBD is generally at least 0.55 ml/g; suitably at
least 0.6 ml/g, and preferably at least 0.62 ml/g. Generally a
catalyst composition based on an amorphous silica alumina carrier,
especially one essentially free of aluminosilicate zeolite,
suitably has a CBD in the range of from 0.60 to 0.65 ml/g.
[0060] For most preferred formulations containing amorphous
silica-alumina or zeolite Y oxidic materials it is thus preferred
that the Group VIb metal is tungsten present in an amount in the
range of from 20 to 27 wt %, most preferably 21 to 27 wt %,
especially 21 wt %, calculated as the trioxide and based on total
weight of catalyst, and that the Group VIII metal is nickel present
in an amount in the range of from 4 to 6 wt %, preferably 5 to 6 wt
%, especially 5 wt %, calculated as the oxide and based on total
weight of catalyst.
[0061] It can be difficult to impregnate such a high amount of
metals using conventional impregnation solutions. We have found
particularly that the use of an organic compound having at least
two moieties selected from carboxyl, carbonyl and hydroxyl, but
especially from carboxyl groups, assists in the impregnation.
[0062] The present invention therefore provides a process for the
preparation of a catalyst composition of the invention, which
comprises drying or calcining a carrier of the present invention,
if necessary or desired, and depositing at least one hydrogenation
metal selected from Group VIb and Group VIII in the appropriate
amount, wherein the deposition is effected by an impregnation
solution containing an organic compound having at least two
moieties selected from carboxyl, carbonyl, and hydroxyl groups.
Following deposition the composition is suitably dried at elevated
temperature, or by aging at room temperature until drying is
effected. Most suitably drying occurs at a temperature in the range
of from 100 to 200.degree. C., eg 120.degree. C. Calcination is
preferably carried out, eg at a temperature in the range of from
200 to 500.degree. C., but is optional.
[0063] The process preferably utilises an organic compound which is
an organic acid selected from citric acid, tartaric acid, oxalic
acid, malonic acid and malic acid.
[0064] Where the inorganic refractory oxide material of the carrier
is an amorphous material, and particularly an amorphous alumina or
the more preferred amorphous silica alumina, and is essentially
free of zeolitic material, then the catalyst composition may
further usefully contain one or more promoter elements.
[0065] Promoters to enhance the performance of catalysts based on
amorphous carrier materials are known and described in the art.
Thus silicon promotion is disclosed for amorphous catalyst
compositions for a variety of uses in WO 95/11753, U.S. Pat. No.
5,507,940, EP-A-533,451, and EP-A-586,196. Other promoters are also
known particularly for use in amorphous-based hydrocracking
catalysts, for example in US-A-2002/0160911 and U.S. Pat. No.
6,251,261 the use of boron and phosphorus is disclosed in addition
to silicon as a promoter.
[0066] Thus the catalyst composition of the invention when
utilising a shaped carrier of the invention consisting essentially
of an amorphous inorganic refractory oxide material may contain in
the range of from 0 to 20 wt %, preferably 0.1 to 15 wt %, and more
preferably 0.1 to 10 wt % of a promoter element selected from
silicon, boron and phosphorus, preferably silicon and boron,
especially silicon. Where the promoter is silicon and the oxide
comprises a silica material, then the amount of promoter silicon is
additional to the amount of silicon present in the silica oxide
material. Preferably the oxide is silica-alumina and the promoter
is selected from silicon and boron; most preferably the promoter is
silicon.
[0067] Many silicon sources can be used. Thus, it is possible to
use ethyl orthosilicate Si(OEt).sub.4, siloxanes, polysiloxanes,
silicones, silicone emulsions, halide silicates such as ammonium
fluorosilicate (NH.sub.4).sub.2SiF.sub.6 or sodium fluorosilicate
Na.sub.2SiF.sub.6. The silicomolybdic acid and its salts, and the
silicotungstic acid and its salts can also be used advantageously.
The silicon may also be added by, for example, impregnation of
ethyl silicate in solution in a water/alcohol mixture. The silicon
can be added by, for example, impregnation of a silicon compound of
silicone type or silicic acid that is suspended in water.
[0068] The boron source may be boric acid, preferably orthoboric
acid H.sub.3BO.sub.3, ammonium biborate or ammonium pentaborate,
boron oxide, or boric esters. Boron can be introduced, for example,
in the form of a mixture of boric acid, oxidized water and a basic
organic compound that contains nitrogen, such as ammonia, primary
and secondary amines, cyclic amines, the compounds of the pyridine
family and quinolines, and the compounds of the pyrrole family.
Boron may be introduced by, for example, a solution of boric acid
in a water/alcohol mixture.
[0069] Suitable phosphorus sources are orthophosphoric acid
H.sub.3PO4, and its salts and esters, such as the ammonium
phosphates. The phosphorus can, for example, be introduced in the
form of a mixture of phosphoric acid and a basic organic compound
that contains nitrogen, such as ammonia, primary and secondary
amines, cyclic amines, compounds of the pyridine family and
quinoliines and compounds of the pyrrole family.
[0070] We have found that the increase in catalyst activity that
results from treating the hydrocracking catalyst with a liquid
silicon-containing compound is confined to catalysts based on a
predominantly amorphous silica-alumina carrier, and is not achieved
when using an aluminosilicate zeolite carrier. Indeed, it has been
found that the presence of aluminosilicate zeolite material in the
amorphous silica-alumina carrier reduces the advantageous
properties imparted by the promoter. Accordingly where the catalyst
of the invention contains a promoter element then the carrier has
to be essentially free of aluminosilicate zeolite, i.e. the amount
of aluminosilicate zeolite in the carrier is less than 1% wt, based
on total carrier, more preferably less than 0.5% wt and even more
preferably less than 0.1% wt. Most preferably, the carrier contains
no aluminosilicate zeolite.
[0071] A promoted hydrocracking catalyst employed in the process of
the present invention preferably comprises at least 0.5% wt of
silicon based on total weight of catalyst, which silicon has been
incorporated in the catalyst by treating the amorphous
silica-alumina carrier with a liquid silicon-containing compound.
For the avoidance of doubt, the amount of silicon incorporated by
treatment with the liquid silicon-containing compound is additional
to the silicon in the amorphous silica-alumina carrier. The
additional silicon may be incorporated by treating the carrier with
a liquid-silicon containing compound either before or after the
metal components have been deposited on the carrier, however, in a
preferred embodiment of the present invention the carrier is
treated with the liquid silicon-containing compound after the metal
components have been deposited on the carrier.
[0072] The liquid silicon-containing compound may be any
silicon-containing compound that may act as a source of silicon and
which may be applied to the carrier in liquid form. Preferably, the
liquid silicon-containing compound is of general formula: 1
[0073] wherein U, V, W, X, Y, and Z can each individually and
independently represent --R, --OR, --Cl, --Br, --SiH.sub.3, --COOR,
--SiH.sub.nCl.sub.m, R being either hydrogen, or an alkyl,
cycloalkyl-, aromatic, alkyl aromatic, alkylcycloalkyl radical
having from 1 to 30 carbon atoms, "n" and "m" being whole numbers
in the range of from 1 to 3 and "a" being a whole number in the
range of from 0 to 1000. Preferably "a" is no more than 100, more
preferably no more than 80, as liquids wherein "a" is greater than
100 have a high viscosity and are thus inconvenient to apply to the
carrier.
[0074] In a particularly preferred embodiment, the liquid
silicon-containing compound is of general formula 2
[0075] wherein U, V, W, X, Y, and Z can each individually and
independently represent --R or --OR, R being either hydrogen, or an
alkyl, cycloalkyl, alkylcycloalkyl radical having from 1 to 30
carbon atoms and "a" being a whole number in the range of from 0 to
60.
[0076] Examples of liquid silicon-containing compounds that may
advantageously be employed in the present invention include alkyl
orthosilicates such as ethyl orthosilicate (Si(OEt).sub.4),
methyltriethyl siloxane (Si(OEt).sub.3Me), and silicone oils such
as polydimethylsiloxane.
[0077] A convenient means of treating the carrier with the liquid
silicon-containing compound comprises adding the liquid to the
carrier and subsequently heating the silicon-liquid treated carrier
at elevated temperature, typically in the range of from 100 to
400.degree. C. In order to facilitate the treatment, the liquid
silicon-containing compound may optionally be dissolved in a
suitable organic solvent such as a lower alkane, however, in some
circumstances, for example when preparing a large quantity of
catalyst, the liquid silicon-containing compound may be applied
neat. As will be understood by those skilled in the art, the amount
of liquid silicon-containing compound applied to the carrier may
vary depending on the particular silicon-containing compound
employed, however, it is preferably such that the amount of silicon
deposited on the carrier, as determined by elemental analysis, is
at least 1% wt, based on total catalyst. More preferably the amount
of silicon is in the range of from 1 to 10% wt, even more
preferably 1 to 5% wt, based on total catalyst.
[0078] In a preferred embodiment of the present invention, the
promoted hydrocracking catalyst is prepared by a process which
comprises impregnating an amorphous silica-alumina carrier with a
Group VIII metal and a Group VIB metal, heating the impregnated
carrier at a temperature in the range of from 150 to 500.degree.
C., treating the impregnated carrier with a liquid
silicon-containing compound, and then heating the silicon-liquid
treated catalyst at a temperature in the range of from 100 to
300.degree. C.
[0079] When preparing the hydrocracking catalyst in accordance with
the above preferred embodiment, the activity of the catalyst may be
optimised by varying the temperature at which the catalyst is
heated. In this regard, very good results have been achieved when
the heating temperature following metal impregnation is in the
range of from 150 to 250.degree. C., and the heating temperature
following silicon-compound treatment is in the range of from 150 to
250.degree. C.
[0080] In the process of the present invention, all hydrocracking
catalysts of the invention, whether promoted or not, are preferably
sulphided prior to use. The catalyst may conveniently be sulphided
by any of the techniques known in the art, such a ex-situ or
in-situ sulphidation. For example, sulphidation may be performed by
contacting the catalyst with a sulphur-containing gas, such as a
mixture of hydrogen and hydrogen sulphide, a mixture of hydrogen
and carbon disulphide or a mixture of hydrogen and a mercaptan,
such as butylmercaptan. Alternatively, sulphidation may be carried
out by contacting the catalyst with hydrogen and a
sulphur-containing hydrocarbon oil, such as sulphur-containing
kerosene or gas oil. The sulphur may also be introduced into the
hydrocarbon oil by the addition of a suitable sulphur-containing
compound, for example dimethyldisulphide or
tert-nonylpolysulphide.
[0081] The present invention also provides a process for converting
a hydrocarbonaceous feedstock into lower boiling materials which
comprises contacting the feedstock with hydrogen at elevated
temperature and elevated pressure in the presence of a catalyst
composition according to the present invention. Such a process is
commonly termed hydrocracking.
[0082] Examples of such processes comprise single-stage
hydrocracking, two-stage hydrocracking, and series-flow
hydrocracking. Definitions of these-processes can be found in pages
602 and 603 of Chapter 15 (entitled "Hydrocarbon processing with
zeolites") of "Introduction to zeolite science and practice" edited
by van Bekkum, Flanigen, Jansen; published by Elsevier, 1991.
[0083] It has been found that particularly with catalysts
containing carriers comprising the preferred amorphous silica
alumina and/or zeolitic materials of the present case and the high
metals contents mentioned above, the catalyst formed can also
exhibit good hydrodesulpurisation of the remaining sulphur in a
conventional hydrocracking feedstock. Furthermore the presence of
nitrogen contaminants in the feedstock does not hinder or
deactivate the catalysts of the invention.
[0084] It will be appreciated that the hydroconversion processes of
the present invention can be carried out in any reaction vessel
usual in the art. Thus the process may be performed in a fixed bed
or moving bed reactor. Also the catalyst of the invention may be
used in conjunction with any suitable co-catalyst or other
materials usual in the art. Thus for example the catalyst of the
invention may be used in stacked bed formation with one or more
other catalysts useful in hydroprocessing, for example with a
catalyst containing a different zeolite, with a catalyst containing
a faujasite zeolite of different unit cell size, with a catalyst
utilizing an amorphous carrier, and so on. Various stacked bed
combinations have been proposed in the lierature: WO-99/32582;
EP-A-310,164; EP-A-310,165; and EP-A-428,224 may, for example, be
mentioned. As noted above, with preferred catalyst compositions of
the present invention additional post-treatment with a
hydrotreating catalyst to remove residual sulphur may not be
necessary.
[0085] The hydrocarbonaceous feedstocks useful in the present
process can vary within a wide boiling range. They include
atmospheric gas oils; coker gas oils; vacuum gas oils; deasphalted
oils; fractions, eg gas oils and waxes, obtained from a
Fischer-Tropsch synthesis process, long and short residues,
catalytically cracked cycle oils, thermally or catalytically
cracked gas oils, and syncrudes, optionally originating from tar
sand, shale oils, residue upgrading processes and biomass.
Combinations of various hydrocarbon oils may also be employed. The
feedstock will generally comprise hydrocarbons having an initial
boiling point of at least 330.degree. C. The boiling range will
generally be from about 330 to 650.degree. C., with preference
being given to feedstocks having a boiling range of from about 340
to 620.degree. C. The feedstock may have a nitrogen content of up
to 5000 ppmw (parts per million by weight) and a sulphur content of
up to 6% w. Typically, nitrogen contents are in the range from 250
to 2000 ppmw and sulphur contents are in the range from 0.2 to 5%
w. It is possible and may sometimes be desirable to subject part or
all of the feedstock to a pre-treatment, for example,
hydrodenitrogenation, hydrodesulphurisation (HDS) or
hydrodemetallisation, methods for which are known in the art.
[0086] The process of the invention may conveniently be carried out
at a reaction temperature in the range of from 250 to 500.degree.
C., preferably in the range of from 300 to 450.degree. C.
[0087] The present process is preferably carried out at a total
pressure (at the reactor inlet) in the range of from
3.times.10.sup.6 to 3.times.10.sup.7 Pa, more preferably from
4.times.10.sup.6 to 2.5.times.10.sup.7 Pa and even more preferably
from 8.times.10.sup.6 to 2.times.10.sup.7 Pa. Where a hydrocracking
process is carried out at a low pressure of, for example
4.times.10.sup.6 to 1.2.times.10.sup.7 Pa, this may be termed `mild
hydrocracking`.
[0088] The hydrogen partial pressure (at the reactor inlet) is
preferably in the range from 3.times.10.sup.6 to 2.9.times.10.sup.7
Pa, more preferably from 4.times.10.sup.6 to 2.4.times.10.sup.7 Pa
and still more preferably from 8.times.10.sup.6 to
1.9.times.10.sup.7 Pa.
[0089] A space velocity in the range from 0.1 to 10 kg feedstock
per litre catalyst per hour (kg.1.sup.-1.h.sup.-1) is conveniently
used. Preferably the space velocity is in the range from 0.1 to 10,
particularly from 0.2 to 8, and preferably from 0.5 to 5
kg.1.sup.-1.h.sup.-1.
[0090] The ratio of hydrogen gas to feedstock (total gas rate or
the gas/feed ratio) used in the present process will generally be
in the range from 100 to 5000 N1/kg, but is preferably in the range
from 200 to 3000 N1/kg, more preferably 250 to 2000 N1/Kg.
[0091] The hydrocracking process of the present invention may be
used to particularly advantageous effect in single-stage
hydrocracking, wherein it gives a good efficiency of conversion
even on exposure to feedstocks comprising nitrogen and
sulphur-containing contaminants.
[0092] One application of single-stage hydrocracking is the
production of middle distillate fractions. Middle distillate
fractions are liquid fractions having a boiling point in the range
of from 150 to 370.degree. C., and include products such as
kerosene (150 to 250.degree. C.) and gas oil (250 to 370.degree.
C.). There is a growing demand for middle distillate products, and
as such there is always a need for hydrocracking processes that
show a strong selectivity for middle distillates with minimum
formation of gaseous (C.sub.1-C.sub.4) material, i.e. processes
whose products contain low amounts of gaseous material and high
amounts of middle distillate. In this regard, the hydrocracking
process of the present invention has proven to be extremely
selective at converting heavy distillate feedstocks, such as heavy
gas oils or deasphalted oils to middle distillate fractions.
[0093] Accordingly, a preferred embodiment of the present invention
provides for the single-stage conversion of a heavy gas oil or a
deasphalted oil to a middle distillate fraction.
[0094] The present invention will now be illustrated by the
following Examples.
EXAMPLES
[0095] By the following general procedure catalyst carriers and
catalysts were prepared using different amounts of zeolite and
inorganic refractory oxide in each catalyst formulation as noted
below.
[0096] General Procedure:
[0097] A catalyst carrier was prepared by mixing a zeolite with
refractory inorganic oxide in the proportions required. Water and
acid were added in order to achieve the specified LOI and pH and
the mixture mulled in a mix-muller until an extrudable mix was
obtained. The mixture was then extruded, together with an extrusion
aid (Superfloc), into extrudates having, in cross-section, a
tri-lobe shape. The extrudates were dried statically for 2 hours at
120.degree. C. and then calcined for 2 hours at 535.degree. C. The
catalyst particles so-obtained were cut to be of regular length
with a diameter of either 1.5 mm or 2.5 mm, measured from the top
to the bottom of a nominal triangle formed by the tri-lobe.
[0098] The metal hydrogenation components of nickel and tungsten
were then incorporated by impregnation of the pellets with an
homogenized aqueous solution of nickel nitrate and ammonium
metatungstate. Citric acid or malic acid was incorporated into
certain of the impregnation solutions as noted. The impregnated
extrudates were dried at ambient conditions in hot circulating air
for 1 hour and then at 120.degree. C. for 2 hours and finally
calcined at 500.degree. C. for 2 hours.
[0099] Activity Testing
[0100] The hydrocracking performance of the catalysts was assessed
in a number of second stage series-flow simulation tests. The
testing was carried out in once-through microflow equipment which
had been loaded with a top catalyst bed comprising 1 ml C-424
catalyst (commercially available from Criterion Catalysts &
Technologies USA) diluted with 1 ml of 0.1 mm SiC particles and a
bottom catalyst bed comprising 10 ml of the test catalyst diluted
with 10 ml of 0.1 mm SiC particles. Both catalyst beds were
presulphided prior to testing.
[0101] Each test involved the sequential contact of a
hydrocarbonaceous feedstock (a heavy gas oil) with the top catalyst
bed and then the bottom catalyst bed in a once-through operation
under the following process conditions: a space velocity of 1.5 kg
heavy gas oil per litre catalyst per hour (kg.1.sup.-1.h.sup.-1), a
hydrogen gas/heavy gas oil ratio of 1440 N1/kg, a hydrogen sulphide
partial pressure of 5.6.times.10.sup.5 Pa (5.6 bar) and a total
pressure of 14.times.10.sup.6 Pa (140 bar).
[0102] A standard heavy gas oil test feed was used having the
following properties:
1 Carbon content 86.64% w Hydrogen content 13.36% w Sulphur (S)
content 122 ppmw Nitrogen (N) content 12 ppmw Added n-Decylamine
12.3 g/kg (equivalent to 1100 ppmw N) Total nitrogen (N) content
1112 ppmw Density (15/4.degree. C.) 0.8805 g/ml Density
(70/4.degree. C.) 0.8463 g/ml Molar weight 433 g Initial boiling
point 355.degree. C. 50% w boiling point 425.degree. C. Final
boiling point 606.degree. C. Fraction boiling below 370.degree. C.
2.57% wt Fraction boiling above 540.degree. C. 10.0% wt
[0103] Hydrocracking performance was assessed at conversion levels
between 40 and 90% wt net conversion of feed components boiling
above 370.degree. C. To compare activity, the obtained results,
expressed as the temperature required to obtain 65% wt net
conversion of feed components boiling above 370.degree. C., are
shown in the Tables below.
[0104] Hydrodesulphurisation (HDS) activity was assessed using the
same test feed and under the same conditions as above but without
using hydrogen sulphide addition.
[0105] Loss on ignition (LOI) was assessed by the method
hereinbefore described. Compacted bulk density was assessed
following the method of ASTM D 4180-03 except that a tamper is
placed on the top of the test sample within a 250 ml graduated
cylinder placed firmly on a vibrating table, and the sample is
assessed without predrying and a correction for dry weight is made
separately according to the formula 1 CBD = measured CBD .times. (
100 - LOI ) 100 .
[0106] Here LOI is determined by the same method described herein
but with heating to 485.degree. C.
[0107] Total pore volume and mesopore volume were determined by
mercury intrusion porosimetry following ASTM D4284-03.
[0108] In carriers C to K the same high surface area USY zeolite Y
was used and is a very ultrastable zeolite Y having a unit cell
size of 24.32 .ANG., a molar silica to alumina ratio of 29, a BET
surface area of 893 m.sup.2/g, and a micropore volume of 0.298
ml/g, prepared as described in WO 2004/047988. Herein, unit cell
size is determined by X-ray diffraction using ASTM D 3942-80; SAR
is bulk or overall SAR and is determined by chemical analysis; BET
surface area is determined by the BET method of Brunauer, Emmett
and Teller, J.Am. Chm. Soc., 60, 309 (1938), and ASTM D4365-95
using a single point assessment from nitrogen adsorption at a p/po
value of 0.03; micropore voume is assessed by the t-plot method
using nitrogen as adsorbate as described by Lippens, Linsen and de
Boer, Journal of Catalysis, 3-34 (1964).
[0109] The carriers used have the following compositions. All
percentages are percentages by weight, basis total carrier. Unless
otherwise stated, the amorphous silica alumina is Al--Si:55-45% w
and the alumina is wide pore alumina, both available from Criterion
Catalysts and Technologies, USA (CC&T).
[0110] Carrier A has 10% USY zeolite Y of SAR 10; 22.5% alumina;
62.5% amorphous silica alumina
[0111] Carrier B has 10% USY zeolite of SAR 10; and 90% amorphous
silica alumina
[0112] Carrier C has 48% high surface area USY zeolite Y; 8%
alumina; 44% amorphous silica alumina
[0113] Carrier D has 50% high surface area USY zeolite Y; 8%
alumina; 42% amorphous silica alumina
[0114] Carrier E has 45% high surface area USY zeolite Y; 9%
alumina; 46% amorphous silica alumina
[0115] Carrier F has 45% high surface area USY zeolite Y; 9%
alumina; 46%amorphous silica alumina
[0116] Carrier G has 35% high surface area USY zeolite Y; 34%
silica alumina (containing 6% silica, available from CC&T); 31%
wide pore alumina available from CCIC
[0117] Carriers H to K have 35% high surface area USY zeolite Y;
10% alumina; 55% amorphous silica alumina.
[0118] The catalysts used have the following metal loadings given
as % w basis total catalyst weight.
[0119] Catalysts 1,2 and 14 have 5 wt % nickel and 21 wt %
tungsten
[0120] Catalysts 3, 4, 7, and 13 have 3.3 wt % nickel and 16 wt %
tungsten
[0121] Catalysts 5, 6, 8 to 11 have 4 wt % nickel and 17 wt %
tungsten
[0122] Catalyst 12 has 2 wt % nickel and 6.5 wt % tungsten.
[0123] In the Tables below TL indicates trilobe; TX indicates a
shaped trilobe of the type described in WO 03/013725.
2 Hg total pore LOI extrusion Acidity volume Hg meso pore mix
extrusion mix CBD (PV) volume % PV in Carrier Shape % w pH g/ml
ml/g ml/g mesopores A 1.6 mm 0.52 0.66 B 1.6 mm 0.44 0.917 C 2.5 mm
54.80 3.4 0.52 0.516 0.368 71.31 D 2.5 mm 59.60 3.6 0.40 0.740
0.520 70.27 E 2.5 mm 56.80 3.7 0.43 0.696 0.490 70.40 F 2.5 mm
56.80 3.7 0.38 0.696 0.487 69.97 G 2.5 mm 60.40 5.8 0.42 0.864
0.459 53.12 H 2.5 mm 61.20 7.0 0.39 0.862 0.491 56.96 I 2.5 mm
61.60 4.2 0.42 0.782 0.558 71.35 J 2.5 mm 61.00 4.7 0.40 0.839
0.579 69.01 K 2.5 mm 58.60 4.4 0.42 0.778 0.576 74.04
[0124]
3 Effect of carrier CBD/pore volume Carrier Hg Mono Tri+- Carrier
pore volume T 65% w 370.degree. C.+ C1-C4 C5-150.degree. C.
150-370.degree. C. arom. Di-arom. arom. Catalyst Carrier CBD g/ml
ml/g .degree. C. % w % w % w % wof % wof % wof 1 A 0.52 0.66 398
2.8 27.4 69.8 47 81 75 2 B 0.44 0.92 399 2.3 27.7 70.1 44 80 75 3 C
0.52 0.52 374 4.7 36.8 58.4 28 71 64 4 D 0.40 0.74 371 4.1 34.5
61.4 44 85 78 In catalysts 1 and 2, a reduction solely in CBD
brings little activity or selectivity advantage. The reduced CBD
and increased mesopore volume shown by catalyst 4 of the invention
however displays a higher activity, selectivity and hydrogenation
compared with catalyst 3.
[0125]
4 Effect of shape and surface area/metal load Carrier Carrier Hg T
65% w Mono Di- Tri+- CBD surface Area W 370+ C1-C4 C5-150.degree.
C. 150-370.degree. C. arom. arom. arom. Catalyst Carrier Shape mm
g/ml m2/g Ni % w % w .degree. C. % w % w % w % wof % wof % wof 5 E
TL 2.5 0.43 257 4 17 377 4.8 35.2 60.0 37 82 76 6 F TX 2.5 0.38 257
4 17 376 4.5 33.5 62.0 38 81 74 .sup. 7.sup.2 F TX 2.5 0.38 257 3.3
14 375 3.2 33.8 63.0 38 82 78
[0126]
5 Effect of mesopore volume Carrier Carrier Hg Hg mesopore T 65% w
Mono Di- Tri+- CBD pore volume volume 370+ C1-C4 C5-150.degree. C.
150-370.degree. C. arom. arom. arom. Catalyst Carrier g/ml ml/g
ml/g .degree. C. % w % w % w % wof % wof % wof 8.sup.2 G 0.42 0.86
0.46 381 4.4 34.3 61.3 37 81 70 9.sup.2 H 0.39 0.86 0.49 380 4.3
33.8 61.9 39 82 76 10.sup.2 I 0.42 0.78 0.56 380 4.0 34.1 61.9 43
85 75 11.sup.1 J 0.40 0.84 0.58 377 3.3 33.6 63.1 42 83 77
[0127]
6 Effect of metals content T 65% w Mono Tri+- Ni W 370+ C1-C4
C5-150.degree. C. 150-370.degree. C. arom. Di-arom. arom. HDS
Catalyst Carrier % w % w .degree. C. % w % w % w % wof % wof % wof
% wof 12.sup.1 K 2 6.5 382 3.8 35 61.0 44 81 72 76 13.sup.1 K 3.3
16.2 380 3.3 33 63.2 71 91 83 92 14.sup.1 K 5 21 378 3.5 31 65.4 77
94 87 93 .sup.1impregnation solution contains citric acid
.sup.2impregnation solution contains malic acid % wof indicates
percent weight removed basis original amount in feed.
* * * * *