HYDROCRACKING CATALYST COMPOSITION

The present invention concerns hydrocracking catalyst compositions, their preparation and their use in

hydrocracking of hydrocarbons.

Hydroconversion processes are important in the modern world in providing important basic fuels for everyday life. As it becomes of an increasing necessity to utilize heavier crude oil feedstocks, the oil refining industry has turned to hydrocracking processes to provide the lighter basic fuels which modern society demands. In certain regions, eg North America, the lighter liquid products boiling below 191 °C are more in demand than middle distillate products. Such lighter products are called the naphtha fractions, with heavy naphtha (the fraction boiling from 82 °C to 191 °C) being particularly desirable. There has been considerable effort devoted to the development of hydrocracking catalysts which combine high naphtha selectivity with a low tendency to overcrack towards light products, in particular to the less

valuable C1-C3 and C4 gaseous by-products, in combination with limited hydrogenation of aromatic rings.

Naphtha preferably has a high amount of aromatics as this gives a high octane number for the gasoline derived from it. A further advantage of less aromatics

hydrogenation is that less hydrogen is consumed which is attractive from a process operation point of view.

Limited hydrogenation and the resulting high aromatics content, is not easily achieved as hydrocracking catalyst preferably has a high hydrogenation activity in order to prevent overcracking of the feedstock.

Summary of the Invention

We have now found an hydrocracking catalyst having significantly reduced aromatics hydrogenation activity while still obtaining a high amount of desired product. The hydrocracking catalyst according to the present invention comprises a faujasite containing refractory oxide support, one or more catalytically active metals and additionally polyalkylene polyamine.

Detailed Description of the Invention

The present invention comprises polyalkylene

polyamine. The polyalkene polyamine preferably is a compound according to formula (I)

H ₂ N - [ -(CH ₂ ) _m - NH ] _n - (CH ₂ ) _P - NH ₂ (I)

in which m, n and p are integers of from 1 to 5, more specifically of from 2 to 4. Most preferably, the

polyalkylene polyamine is diethylenetriamine or

triethylenetetramine .

The amount of polyalkylene polyamine present in the catalyst before calcination preferably is of from 0.01 to 10 % by weight, based on total weight of catalyst, more preferably of from 0.05 to 5 % by weight. More

preferably, the amount is at least 0.08, more preferably at least 0.10, more preferably at least 0.15, most preferably at least 0.20 % by weight. The amount

preferably is at most 4 % by weight, more preferably at most 3 % by weight, more preferably at most 2 % by weight, more preferably at most 1.5 % by weight, more preferably at most 1 % by weight.

The present invention further relates to a process for the preparation of a hydrocracking catalyst according to the present invention which process comprises treating a refractory oxide support with a solution, preferably an aqueous solution, comprising polyalkylene polyamine and catalytically active metal. The support preferably has been calcined before being treated with the polyalkylene polyamine containing solution. Dependent on the kind and amount of catalytically active metals, the support can be treated with either a single solution comprising all components to be incorporated or two or more solutions of which at least one contains a polyalkylene polyamine and at least one contain a catalytically active metal. The use of a plurality of solutions can be required if metal compounds would dissipitate if present in a single solution .

The solution preferably comprises such amount of polyalkylene polyamine as to obtain the polyalkylene polyamine content described above. Preferably, the polyalkylene polyamine containing aqueous solution further comprises one or more catalytically active metals. If such solution is to be used for impregnation, the amount of water, metal containing compound and polyalkylene polyamine are to be chosen such as to prevent the metal dissipitation . Dissipitated metals are acceptable if the solution is used in co-mulling. The exact amount of polyalkylene polyamine depends on the amount of catalytically active metal and the kind of metal or metals present. The solution will generally contain of from 1 to 25 % by weight of polyalkylene polyamine, more specifically of from 2 to 20 % by weight, basis total amount of aqueous solution.

The catalytically active metal and polyalkylene polyamine can be incorporated into the catalyst in any way known to someone skilled in the art such as by co- mulling and/or by impregnation. It is preferred to apply impregnation, more preferably pore volume impregnation.

If impregnation is applied, it is preferred that the polyalkylene polyamine is added as part of a

catalytically active metals containing solution.

Metal containing compounds suitable for use in impregnation are compounds which are soluble in water in the presence of polyalkylene apolyamine. Preferred metal containing compounds for use in impregnation are metal oxides and metal salts which are soluble in water in the presence of polyalkylene apolyamine. A suitable metal oxide is molybdenum oxide, more specifically molybdenum trioxide. Metal salts preferred for impregnation are acetates, carbonates, nitrates and ammonium salts, such as nickel acetate, nickel nitrate, nickel carbonate, and ammonium metatungstate, as are well known to those skilled in the art. For environmental reasons nitrate and carbonate salt solutions are preferred over the use of acetate solutions.

The present invention is defined based on the

Periodic Table of Elements which appears on the inside cover of the CRC Handbook of Chemistry and Physics ( ^x The Rubber Handbook' ) , 66 ^th edition and using the CAS version notation .

Catalytically active metals that preferably are present in the catalyst according to the present

invention are one or more Group VIB metals, preferably molybdenum and/or tungsten, and one or more non-noble

Group VIII metals, preferably cobalt and/or nickel. The catalyst according to the present invention generally will not be calcined before sulfurization . Therefore, before sulfurization the metal components generally will be present in the form of the metal oxide or metal salt as applied in impregnation, or in the form of the corresponding complex with polyalkylene polyamine.

The catalyst composition will preferably contain at least two catalytically active metal 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.

The present catalyst composition may contain up to

50 parts by weight of catalytically active component, calculated as metal per 100 parts by weight (dry weight) of total catalyst composition. The catalyst composition may contain from 0.4 to 20, especially 0.8 to 15, more specifically 1 to 10 parts by weight of Group VIB

metal (s) and/or from 0.1 to 10, more preferably from 0.5 to 8, especially 1 to 5, parts by weight of Group VIII metal (s), calculated as metal per 100 parts by weight (dry weight) of total catalyst composition.

An impregnating solution for preparing catalyst according to the present invention is preferably prepared by adding one or more catalytically active metal

components and the polyalkylene polyamine to water while stirring and optionally at increased temperature such as of from 20 to 95 °C, more specifically of from 30 to 80 °C, in order to obtain an aqueous solution in which the majority of the catalytically active metal components have been dissolved. Preferably, at least 80 % by weight of the added metal containing components has been

dissolved, more specifically at least 90 %, more

specifically at least 95% and most preferably all added metal containing components have been dissolved. A preferred solution for use in the present invention is an aqueous solution comprising a polyalkylene polyamine according to formula I and one or more metal compounds in which the metal is chosen from the group consisting of nickel, cobalt, tungsten and molybdenum.

The order of adding the, or each of the,

catalytically active metal components and the

polyalkylene polyamine depends on the kind and amount of the metal components used for preparing the aqueous solution .

If a nickel and tungsten containing catalyst is to be prepared, it is preferred to add a nickel containing component to water at room temperature, subsequently the polyalkylene polyamine and subsequently the tungsten containing component. If desired, further water can be added at or between any of these additions. Stirring and heating are applied as appropriate. The amount of nickel containing component and the amount of tungsten

containing component depends on the amount of each of these metals to be present in the final catalyst. The total amount of water depends on the pore volume of the support to be impregnated.

The catalyst according to the present invention are dried after the catalytically active metals have been incorporated, but preferably not calcined before

sulfurization . Sulfurization usually is carried out after the catalyst has been loaded into the reactor.

Calcination is preferably only carried out during

sulfurization as it is believed that the polyalkylene polyamine assists in keeping the metals well dispersed over the support and preventing the formation of bulky metal oxide phases in the catalyst. In the course of sulfidation the polyalkylene polyamine is thought to be largely removed through hydrotreating reactions and evaporation. It is thought that, once a certain degree of sulfidation is achieved, maintaining the now improved dispersion does no longer require the presence of the additive. Preferably, the catalyst according to the present invention is dried at a temperature of at most 300 °C after metal incorporation but before

sulfurization, more specifically at most 250 °C, more specifically at most 200 °C, more specifically at most 150 °C, most specifically at most 100°C. Before

sulfurization, the temperature of the catalyst preferably does not pass the above limits.

The zeolite for use in the present invention

preferably is a faujasite zeolite more specifically a zeolite Y, more specifically zeolite Y having a unit cell size in the range of from 24.30 to 24.60 A, more

specifically of from 24.38 to 24.55 A, more specifically of from 24.42 to 24.52 A, preferably of from 24.42 to 24.50 A. More preferably, the unit cell size is of from 24.43 to 24.49 A. The bulk silica to alumina molar ratio (herein also termed "SAR") of the zeolite preferably is at least 10, preferably above 10, preferably at least

10.2, more preferably at least 10.3, most preferably at least 10.5. The upper limit of the SAR preferably is 15, more specifically at most 14, more preferably at most 13, especially at most 12.5, most preferably at most 12. The surface area of the zeolite generally will be at least 500 m^/g, more specifically at least 600 m^/g, more specifically at least 700 m^/g, more specifically at least 800 m^/g, more specifically at least 850 m^/g, more specifically at least 870 m^/g, most preferably at least

900 m^/g. Generally, the surface area will be at most 1050 m ² /g, more specifically at most 1020 m^/g. A high surface area is advantageous in that it means that there is a large surface area available for catalysis.

The zeolite preferably has an alkali level of less than 0.15 %wt based on the zeolite, more preferably less than 0.10 %wt . The zeolite desirably has as low an alkali level as possible.

The silica to alumina molar ratio of the faujasite zeolite of the invention is the bulk or overall ratio. This can be determined by any one of a number of chemical analysis techniques. Such techniques include X-ray fluoresence, atomic adsorption, and ICP-AES (inductive coupled plasma - atomic emission spectroscopy) . All will provide substantially the same bulk ratio value.

The unit cell size for a faujasite zeolite is a common property and is assessable to an accuracy of

+ 0.01 A by standard techniques. The most common

measurement technique is by X-ray diffraction (XRD) following the method of ASTM D3942-80.

Surface area is determined in accordance with the well known BET (Brunauer-Emmett-Teller ) nitrogen

adsorption technique, often simply termed the BET method. Herein also the general procedure and guidance of ASTM D4365-95 is followed in the application of the BET method to zeolite Y materials. To ensure a consistent state of the sample to be measured, suitably all samples undergo a pretreatment . Suitably the pretreatment involves heating the sample, for example to a temperature of 400 to 500°C, for a time sufficient to eliminate free water, eg 3 to 5 hours. The nitrogen porosimetry measurements utilised in the surface area (BET) determination, can also be used to determine other properties such as mesopore (pores having a diameter of 2 nm or more) area. For the zeolites of the present invention, the mesopore area is generally in excess of 50 m^/g.

All of the above measurement and determination procedures are well known to those skilled in the art.

The zeolites for use in the present invention are suitably prepared by a preparation process which involves a steaming treatement and one or more leaching

treatments.

Preferred zeolites are zeolites having a silica to alumina molar ratio of at least 10, the infrared spectrum of which has a peak at 3700 cm ^-1 but substantially no peaks at 3605 and 3670 cm ^-1 in which the infrared spectrum is measured as described in US application 61/173698.

Further preferred zeolites are zeolite of the

faujasite structure which have a unit cell size in the range of from 24.40 to 24.50 A; a bulk silica to alumina ratio (SAR) in the range of from 5 to 10; and an alkali metal content of less than 0.15 wt% all of which

properties are measured as defined in WO-A-2006/032698.

A further class of preferred zeolites are those of the faujasite structure which have a unit cell size in the range of from 24.42 to 24.52 A; a bulk silica to alumina molar ratio (SAR) in the range of from 10 to 15; and a surface area of from 910 to 1020 m ² /g all of which properties are measured as defined in European

application no. 09177936.3-2104.

Further preferred features of the above zeolites and methods for manufacturing these are described in WO-A- 2006/032698 and in the patent applications claiming the priority of European application no. 09177936.3-2104 in the name of Shell Internationale Research Maatschappij B.V. and US application 61/173698 in the name of PQ

Corporation.

In a catalyst of the present invention, the zeolite component generally is mixed with an amorphous binder component. The amorphous binder component may be any refractory inorganic oxide or mixture of oxides

conventional for such compositions. Generally this is an alumina, a silica, a 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 amount of zeolite in the catalyst when binder is also present may be of from 1 to 90 % by weight, but is preferably in the range of from 2, more preferably 20, especially 50, to 80 % by weight, based on the total catalyst.

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 deactivation, in use in any process that water and/or fluoride is present or

generated. Amorphous silica alumina materials may

usefully contain silica in an amount in the range of from 25 to 95 wt%, most preferably at least 40 wt%. Most preferred, however, as a binder is alumina, particularly boehmite, pseudoboehmite, and gamma alumina.

In the preparation of the catalyst of the invention, following the mixing of zeolite with binder, an acidic aqueous solution may be added to the mixture after which it is co-mulled, extruded and calcined in conventional manner. Any convenient mono-basic acid may be used for the acidic solution; examples are nitric acid and acetic acid. During extrusion, conventionally extrusion aids are utilized; usual extrusion aids include Methocel and

Superfloc .

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 catalyst

extrudates of the required form, e.g. cylindrical or trilobed. The strands formed on extrusion may then be cut to the appropriate length. If desired, the catalyst extrudates may be dried, e.g. at a temperature of from

100 to 300°C for a period of 10 minutes to 3 hours, prior to calcination.

Calcination of the extrudates is conveniently carried out in air at a temperature in the range of from 300 to

850°C for a period of from 30 minutes to 4 hours. As mentioned previously, it is preferred not to calcine the supports after the catalytically active metal and

polyalkylene polyamine have been incorporated into the catalyst .

Typical properties for a catalyst of the invention include a water pore volume in the range of from 0.6 to 0.75 cc/g and a flat plate (FP) crush strength of in excess of 3.5 lb/mm, preferably at least 5, more

preferably in the range of from 5 to 7. Typical catalysts may have an average particle length of from 4 to 6 nm. Typically also a catalyst of the present invention has a compacted bulk density (CBD) of at least 0.50 g/cc, preferably at least 0.58; at most the CBD is suitably

0.65 g/cc. Herein CBD is assessed following the method of ASTM D 4180-03.

The catalyst composition finds especially application as a naphtha-selective catalyst composition. Thus, 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. The catalyst composition according to the present invention preferably has been sulfided prior to use, more specifically sulfided utilising a liquid phase sulfidation agent.

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.

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, most preferably a unit cell size of greater than 24.40 A, with a catalyst utilizing an amorphous carrier, and so on. Various stacked bed combinations have been proposed in the literature: WO-99/32582 ; EP-A-310 , 164 ; EP-A-310, 165; and EP-A-428,224 may, for example, be mentioned.

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, 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. Typically, though, the feedstocks most suited for the process of the

invention are the lighter feedstocks or fractions

obtained by treatment of a feedstock through cracking or fractionation. Such feedstocks include atmospheric and vacuum gas oils, gas oils formed by cracking processes, cycle oils, and similar boiling range feedstocks. The boiling range will generally be of the order of from about 90 to 650°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 wt%. Typically, nitrogen contents are in the range from 10, eg from 100, to 4000 ppmw, and sulphur contents are in the range from 0.01, eg from 2, to 5 wt%. It is possible and may sometimes be desirable to subject part or all of the feedstock to a pre-treatment , for example, hydrodenitrogenation,

hydrodesulphurisation or hydrodemetallisation, methods for which are known in the art.

The process of the invention may conveniently be carried out at a reaction temperature in the range of from 250 to 500°C.

The present process is preferably carried out at a total pressure (at the reactor inlet) in the range of from 3 x 10^ to 3 x 10 ⁷ Pa, more preferably from 8 x 10^ to 2.0 x 10 ⁷ Pa. Where a hydrocracking process is carried out at a low pressure of, for example, up to 1.2 x 10 ⁷ Pa this may be termed ^λ πιί1ά hydrocracking' .

The hydrogen partial pressure (at the reactor inlet) is preferably in the range from 3 x 10^ to 2.9 x 10 ⁷ Pa, more preferably from 8 x 10^ to 1.75 x 10^ Pa.

A space velocity in the range from 0.1 to 10 kg feedstock per litre catalyst per hour (kg.l ^~ l.h ^~ l) is conveniently used. Preferably the space velocity is in the range from 0.1 to 8, particularly from 0.2 to 5 kg.l ^~ i.h-i.

The ratio of hydrogen gas to feedstock (total gas rate) used in the present process will generally be in the range from 100 to 5000 Nl/kg, but is preferably in the range from 200 to 3000 Nl/kg.

The present invention will now be illustrated by the following Examples.

Examples

In the Examples the following test methods have been used:

Unit cell size: Determined by X-ray diffraction using the method of ASTM D-3942-80.

Surface Area: Determined in accordance with the

conventional BET (Brunauer-Emmett-Teller ) method nitrogen adsorption technique as described in the literature at S.

Brunauer, P. Emmett and E. Teller, J. Am. Chm. Soc, 60, 309 (1938), and ASTM method D4365-95. In the

determinations quoted below, the results are given as a single point assessment taken at a nitrogen partial pressure of 0.03 following a high temperature

pretreatment .

Silica to alumina molar ratio (SAR) : Determined by chemical analysis; values quoted are ^x bulk' SAR (that is to say the overall SAR) and not specifically the SAR of the crystalline framework.

Example 1 - Comparative catalyst

This catalyst was prepared in accordance with the teaching of WO 2006/032698. The zeolite was prepared by a method similar to the one described in Example 4 of WO 2006/032698. Faujasite zeolite of SAR 5.2, unit cell size 24.64 A, 12.99 wt% sodium oxide, ex-Zeolyst International, was converted into a low alkali (less than 1.5 wt% alkali oxide) ammonium form Y zeolite using the technique described in U.S. Patent Specification No. 5,435,987

+

which involves K ion exchange of the sodium form zeolite Y, followed by ammonium ion exchange.

This low alkali ammonium form zeolite Y was then steam calcined for 45 minutes at a temperature of 630°C in 100 vol% steam in a rotary kiln to provide a zeolite having a unit cell size 24.42 A and SAR of 5.6. The steamed zeolite was then subjected to an acid- dealumination treatment as a one-step treatment with an aqueous solution of hydrochloric acid in an amount of 0.05 g HCl/g zeolite for at least 1 hour at 60 °C.

The resulting zeolite was of unit cell size 24.50 A, SAR 8.25, alkali content 0.06 wt% and a surface area of

865 m ² /g.

The zeolite Y thus obtained was loaded into a muller at low speed and mixed with alumina (HMPA alumina ex

Criterion Catalysts & Technologies) in an amount

sufficient to provide a weight ratio of zeolite to alumina, dry basis, of 80:20, and Methocel K-15MS in an amount of 1.8 wt% basis total dry solids, was added and the whole mixed at high speed for 1 to 2 minutes.

Methocel K-15MS is an extrusion aid commercially

available from Dow Chemical Company. The metals solution was an aqueous solution of a nickel nitrate solution (14.4 wt% nickel) and an ammonium metatungstate solution (73 wt% tungsten); the overall metals solution contained

6.3 wt% nickel and 20.5 wt% tungsten and had a pH in the range of 2.0 to 2.4.

Deionised water to achieve a loss on ignition in the product of 50 % and nitric acid (2 wt% total dry solids) to peptise the alumina was then added and mixing continued at high speed until the colour of the mix changed to a darker green and large lumps appeared in the mix from agglomeration of the materials. Superfloc, in an amount of 1.0 wt%, basis total dry solids, was then added and the whole mixed for a further 3 to 5 minutes until an extrudable mix was formed. The mix was then extruded in a screw extruder into extrudates having, in cross section, a tri-lobe shape. The extrudates were dried in a rotating drum at a temperature not exceeding 130°C for about 90 minutes, and then calcined at 730 °C for about 2 hours.

The final catalyst had the following composition: 3.3 wt% as nickel oxide (2.6 wt% nickel); 10.6 wt% as tungsten oxide (8.4 wt % tungsten); 68.9 wt% zeolite Y; and 17.2 wt% alumina binder, all basis total catalyst. Example 2 - Catalyst

Faujasite zeolite of SAR 5.6, unit cell size 24.64 A, 12.40 wt% sodium oxide, ex-Zeolyst International, was converted into a low alkali (less than 1.5 wt% alkali oxide) ammonium form Y zeolite using the technique described in U.S. Patent Specification No. 5,435,987

+

which involves K ion exchange of the sodium form zeolite Y, followed by ammonium ion exchange. The resulting zeolite was of unit cell size 24.70 A, SAR 5.6 ,

potassium oxide content 0.45 wt%, and sodium oxide content 0.35 wt%.

This low alkali ammonium form zeolite Y was then steam calcined for 2 hours at a temperature of 630°C in 20 vol% steam in a rotary kiln to provide a zeolite having a unit cell size 24.46 A and SAR of 5.6. The steamed zeolite was then slurried with an aqueous

ammonium chloride containing solution (0.40 kg NH ₄ Cl/kg of dry zeolite) at a temperature of 60 °C and was kept at that temperature during 45 minutes. The slurry contained 18.5 %wt of zeolite. Subsequently, hydrogen chloride was added to the slurry (0.20 kg hydrogen chloride/kg of dry zeolite) . The temperature was kept at 70 °C during 15 minutes. The slurry was then transferred to another tank, diluted with cold water and filtered over a vacuum belt filter. On the belt, the leached zeolite was washed with warm water. The zeolite coming from the belt was

reslurried with an aqueous ammonium chloride containing solution (0.50 kg NH ₄ Cl/kg of dry zeolite) at a

temperature of 60 °C and was kept at that temperature during 1.5 hours minutes. The slurry contained 18.5 %wt of zeolite. Finally, the zeolite was washed with water and dried.

The final zeolite was of unit cell size 24.49 A, SAR

10.5 and a surface area of 940 m^/g.

The zeolite Y thus obtained was loaded into a muller at low speed and mixed with a metals solution for five minutes following which alumina (WPA alumina ex Criterion Catalysts & Technologies) in an amount sufficient to provide a weight ratio of zeolite to alumina, dry basis, of 80:20, and Methocel K-15MS in an amount of 1.8 wt% basis total dry solids, was added and the whole mixed at high speed for 1 to 2 minutes.

A metals solution was prepared by adding 3.47 grams of nickel acetate to 9 grams water at room temperature, stirring, adding 2.76 grams diethylenetriamine and 1.66 grams molybdenum trioxide and subsequently adding further water so that the total weight was 25.4 grams.

The extrudates were impregnated by pore volume impregnation with the metals solution thus obtained.

Subsequently, the catalyst was dried at a temperature well below 100 °C (not calcined) .

The final catalyst contained the metal compounds in the form of salts and oxides at least partly complexed with diethylenetriamine. The amount of each of these metal compounds was not established. However, the amount of the metals present was such that upon calcination the catalyst would have had the following composition: 2.5 wt% as nickel oxide (2.0 wt% nickel); 5.1 wt% as

molybdenum trioxide (3.4 wt % molybdenum); 73.9 wt% zeolite Y; and 18.5 wt% alumina binder, all basis total catalyst .

Example 3 - Activity testing

The hydrocracking performance of the catalysts prepared as described in Examples 2 and 4 were assessed. These catalysts were not further dried before testing of the activity.

The testing was carried out in once-through microflow equipment which had been loaded with a catalyst bed comprising 15 ml of the test catalyst diluted with 15 ml of 0.1 mm SiC particles. After loading, the catalyst bed was presulphided prior to testing. Each test involved the sequential contact of a hydrocarbonaceous feedstock with the catalyst bed in a once-through operation under the following process conditions: a space velocity of 1.5 kg feed oil per 1 catalyst per hour ( kg .1 ^~ 1. h ^~ l ) , a hydrogen gas/feed oil ratio of 1000 Nl/kg, and a total pressure of 11,000 kPa (110 bar) at the inlet.

The test feedstock used had the following properties:

Carbon content 87.80 wt%

Hydrogen content 12.17 wt%

Sulphur content 0.0188 wt%

Nitrogen (N) content 96 ppmw

Added n-Decylamine 10.15 g/kg

(to achieve 1000 ppmv NH ₃ )

Added sulphur ¹ : 8.91 g/kg

(to achieve 5000 ppmv H ₂ S)

Density (15/4 °C) : 0.9064 g/ml

Initial boiling point 175 °C

50 %w boiling point 304 °C

Final boiling point 441 °C

Fraction boiling below 370 °C : 87.70 wt Fraction boiling below 191 °C : 2.90 wt%

¹ Sulphur is added in the form of Sulfrzol 54 which is a catalyst sulfiding agent commercially available from Lubrizol Corporation. Sulfrzol 54 and Lubrizol are trade marks .

Hydrocracking performance was assessed at conversion levels from 55 to 92 wt% net conversion of feed

components boiling above 191°C. Hydrocracking activity, was assessed as the temperature required to obtain 70 %wt net conversion of feed components boiling above 191°C.

The results are shown in Table 1 below.

Table 1

From Table 1, it is clear that the catalyst of the present invention achieves a substantial reduction in aromatics conversion which is also reflected in the reduced hydrogen consumption.

The retention of the aromaticity of the feedstock is confirmed by Table 2 giving an analysis on the naphthenes and aromatics present in the product slate which consists of hydrocarbons containing at least 5 carbon atoms and boiling at a temperature of at most 200 °C. The product is normalised to a conversion of from 77 to 82 % of the product boiling at 191 °C or higher.

Cat. 1 stands for the comparative catalyst prepared according to Example 1, and Cat. 2 stands for the

catalyst prepared according to Example 2.

Naph. stands for naphthenes and Arom. stands for aromatic compounds. C-nr stands for hydrocarbons containing the following number of carbon atoms.

Table 2 clearly shows the higher aromatics retention by the catalyst according to the present invention, accompanied by the generation of less naphthenes.

Table 2

C-nr Ex. 1 Ex. 2 Ex. 1 Ex. 2

Naph . Naph . Arom. Arom.

5 0.39 0.24 0.00 0.00

6 4.78 4.53 0.26 0.81

7 10.59 9.91 2.58 3.59

8 12.61 11.62 3.95 5.60

9 11.23 9.94 3.53 6.81

10 7.71 5.18 4.50 6.49

11 4.08 3.26 0.00 0.00

Total 51.40 44.68 14.82 23.30