A METHOD OF PREPARING A HYDROCRACKING CATALYST

Abstract

The present invention provides a method of preparing a supported catalyst, preferably a hydrocracking catalyst, the method at least comprising the steps of: a) providing a zeolite Y having a bulk silica to alumina molar ratio (SAR) of at least 10; b) contacting the zeolite Y provided in step a) with a base and a surfactant, thereby obtaining a zeolite Y with increased mesoporosity; c) shaping the zeolite Y with increased mesoporosity as obtained in step b) thereby obtaining a shaped 10 catalyst carrier; d) calcining the shaped catalyst carrier as obtained in step c) in the presence of the surfactant of step b), thereby obtaining a calcined catalyst carrier; e) impregnating the catalyst carrier calcined in step d) with a noble metal component thereby obtaining a supported catalyst.

Claims

1. A method of preparing a supported hydrocracking catalyst, the method comprising the steps of: a) providing a zeolite Y having a bulk silica to alumina molar ratio (SAR) of at least 10; b) contacting the zeolite Y provided in step a) with a base and a surfactant, thereby obtaining a zeolite Y with increased mesoporosity; c) shaping the zeolite Y with increased mesoporosity as obtained in step b) thereby obtaining a shaped catalyst carrier; d) calcining the shaped catalyst carrier as obtained in step c) in the presence of the surfactant of step b), thereby obtaining a calcined catalyst carrier; e) impregnating the calcined catalyst carrier obtained in step d) with a noble metal component thereby obtaining a supported catalyst.

2. The method according to claim 1, wherein the zeolite Y provided in step a) has a bulk silica to alumina molar ratio (SAR) of 20 to 100.

3. The method according to claim 1, wherein the surfactant as used in step b) comprises an alkylammonium halide.

4. The method according to claim 1, wherein the zeolite Y with increased mesoporosity as obtained in step b) has a Small Mesopore (30 to 50 Å pore diameters) Peak of at least 0.20 cm.sup.3/g as determined according to Ar adsorption according to NLDFT.

5. The method according to claim 1, wherein the zeolite Y with increased mesoporosity as obtained in step b) has a total mesopore volume in pores with a volume of 2-8 nm as determined according to Ar adsorption according to NLDFT of a range between 0.2 ml/g and 0.65 ml/g.

6. The method according to claim 1, wherein the zeolite Y with increased mesoporosity as obtained in step b) has a ratio of V.sub.s/V.sub.l of at least 1.0, wherein V.sub.s represents small mesopores with a mean diameter of 3 to 5 nm and V.sub.l represents large mesopores with a mean diameter of 10 to 50 nm.

7. The method according to claim 1, wherein the zeolite Y with increased mesoporosity as obtained in step b) has a ratio of V.sub.s/(V.sub.s+V.sub.l) of at least 50%, wherein V.sub.s represents small mesopores with a mean diameter of 3 to 5 nm and V.sub.l represents large mesopores with a mean diameter of 10 to 50 nm.

8. The method according to claim 1, wherein no heat treatment at a temperature of above 500° C. takes place between the contacting of step b) and the shaping of step c.

9. The method according to claim 1, wherein the noble metal in the noble metal component used in in step e) comprises at least one metal selected from the group consisting of ruthenium (Ru), rhodium (Rh), palladium (Pd), silver (Ag), osmium (Os), iridium (Ir), platinum (Pt), gold (Au), and a combination thereof.

10. A supported catalyst obtainable by the method according to claim 1, containing zeolite Y and a noble metal component.

11. The catalyst according to claim 10, wherein the zeolite Y has a ratio of V.sub.s/V.sub.l of at least 1.0, wherein V.sub.s represents small mesopores with a mean diameter of 2 to 5 nm and V.sub.l represents large mesopores with a mean diameter of 10 to 50 nm.

12. The catalyst according to claim 10, wherein the zeolite Y has a ratio of V.sub.s/(V.sub.s+V.sub.l) of at least 50%, wherein V.sub.s represents small mesopores with a mean diameter of 2 to 5 nm and V.sub.l represents large mesopores with a mean diameter of 10 to 50 nm.

13. A process for the conversion of a hydrocarbonaceous feedstock into lower boiling materials, the process comprises contacting the hydrocarbonaceous feedstock with hydrogen at elevated temperature and pressure in the presence of a catalyst as obtained in the method according to claim 1 or the catalyst of claim 10.

Description

EXAMPLES

Zeolite Modifications

[0065] CBV-780, a zeolite Y material, was obtained from Zeolyst International B.V (Delfzijl, The Netherlands). The properties of this zeolite Y material are given in Table 1 below.

TABLE-US-00001 TABLE 1 Properties of zeolite Y material CBV- 780 (as taken from supplier's website) SiO.sub.2/Al.sub.2O.sub.3 Nominal Unit cell Surface mole ratio cation Na.sub.2O size Area (SAR) form [wt. %] [Å] [m.sup.2/g] CBV-780 80 hydrogen 0.03 24.24 780
Modified Zeolite 1 (In Line with the Present Invention)

[0066] An aqueous solution 48 g CTAC (25% solution in water; commercially available from Sigma-Aldrich) and 155 g demi-water was made. To this solution 20 g CBV-780 zeolite (on a dry weight basis) was added and the obtained slurry was heated to 80° C., while being magnetically stirred.

[0067] After one hour at 80° C., 3.2 g NaOH (50% solution in demi-water, prepared with NaOH pellets (VWR Chemicals)) was added and the slurry was stirred for 4 hours at 80° C. Thereafter, the hot slurry was quenched with cold (about 20° C.) demi-water, and filtered and washed thoroughly with demi-water. The filtrate was resuspended in 200 g demi-water and heated to 70° C. while being magnetically stirred. After reaching 70° C., 0.1 g HNO.sub.3 (commercially available in 65% solution in water from Merck KGaA) was added per gram zeolite (total 3.08 g 65% HNO.sub.3). After one hour at 70° C., the slurry was filtered and washed thoroughly with demi-water. The obtained mesoporous zeolite is referred to with ‘MZ1’ or ‘780mp’.

Modified Zeolite MZ1-C (In Line with the Present Invention, but Less Preferred)

[0068] A portion of the ‘MZ1’ (780mp) was dried at 120° C. and subsequently calcined at 760° C. for 1 hour under N.sub.2 atmosphere and subsequently calcined under air at 550° C. for 1 hours. This calcined sample is referred to with ‘MZ1-C’ or ‘780mp-C’.

Modified Zeolite 2 (In Line with the Present Invention)

[0069] An aqueous solution of 72 g CTAC (25% solution in water; Sigma-Aldrich) and 232 g water was made, to which cetyl alcohol (‘CA’; synthesis grade, commercially available from Sigma Aldrich (Zwijndrecht, The Netherlands)) was added as swelling agent in a CA/CTAC molar ratio of 0.5. To this solution 30 g CBV-780 zeolite (on a dry weight basis) was added, and the slurry was heated up to 80° C. while being magnetically stirred. After one hour at 80° C., 4.8 g NaOH (50% solution in demi-water, prepared with NaOH pellets (VWR Chemicals)) was added and the slurry was stirred for 4 hours at 80° C. Thereafter, the hot slurry was quenched with cold (about 20° C.) demi-water, and filtered and washed thoroughly with demi-water. The filtrate was resuspended in 300 g demi-water and heated to 70° C. while being magnetically stirred. After reaching 70° C., 0.1 gram HNO.sub.3 (commercially available in 65% solution from Merck KGaA (Darmstad, Germany)) was added per gram zeolite (total of 4.6 g 65% HNO.sub.3). After one hour at 70° C., the slurry was filtered and washed thoroughly with demi-water. The as-obtained modified zeolite Y is referred to with ‘MZ2’ or ‘780mpSA’ (i.e. treated with a swelling agent).

Powder Analysis of (Modified) Zeolite Y

[0070] Prior to powder analysis, all samples were dried at 120° C., calcined at 760° C. for 1 hour under an N.sub.2 atmosphere and subsequently calcined under air at 550° C. for 2 hours using the two-step calcination procedure, similar to Example 7 of US20130292300A1. This, to remove the surfactant and enable accessibility for sorption experiments.

[0071] The following tests/apparatus were used for the analysis:

[0072] Pore Volumes:

[0073] Total pore volume (‘Total PV’) and mesopore volume (‘mesoPV’) were determined by Argon physisorption.

[0074] To this end, sorption experiments were performed with argon (−186° C.) using a Micromeritics 3FLEX Version 4.03 apparatus. Prior to the adsorption experiments, the samples were outgassed for at least 12 hours under vacuum at 350° C.

[0075] For determining the ‘Total PV’ single-point Argon desorption data at P/PO=0.99 was used.

[0076] For determining the ‘mesoPV’ (in 2-8 nm, 3-5 nm and 10-50 ranges) Argon adsorption data was used, using the HS-2D-NLDFT, Cylindrical oxide, Ar, 87 model from Micromeritics. From this data also the average pore size in the 2-8 nm pore range was calculated. For the ratio ‘mesoPV/Total PV’, the mesoPV in the 2-8 nm pore range was used.

[0077] Argon Surface Area:

[0078] The surface area was determined through Argon adsorption in accordance with the conventional BET (Brunauer-Emmett-Teller) method adsorption technique as described in the literature by S. Brunauer, P. Emmett and E. Teller, J. Am. Chm. Soc., 60, 309 (1938), and ASTM method D4365-95. Surface areas were determined at P/P0=0.03.

[0079] Unit Cell Parameter A0:

[0080] XRD analysis, e.g. in accordance with ASTM D3942-80, was used to determine the unit cell constant.

[0081] The samples were measured on an X′Pert diffractometer from Malvern Panalytical. The samples were measured in a powdered, homogenized form.

[0082] Samples and reference samples (i.e. the untreated parent zeolites) were kept inside a closed radiation cabinet of the diffractometer for at least 16 hours to ensure equal equilibration with the ambient conditions of the cabinet.

[0083] Crystallinity:

[0084] XRD analysis was used to determine crystallinity.

[0085] The crystallinity was determined by comparing the total diffracted intensity of the diffraction pattern of a sample to that of a reference sample (the corresponding parent zeolite). The intensity ratio was reported as a percentage of the reference intensity.

[0086] Bulk silica to Alumina Molar Ratio (SAR):

[0087] The bulk silica to alumina molar ratio (SAR) can be determined through various techniques such as ICP, AAS and XRF resulting in similar outcomes. Here, XRF analysis was applied using a 4 kW WD-XRF analyser.

[0088] The results are given in Table 2 below.

TABLE-US-00002 TABLE 2 overview of (modified) zeolite Y properties. ‘Parent’ means untreated commercial zeolite. CBV-780 MZ1 MZ2 Zeolite/Modified zeolite (parent) (780 mp) (780 mp) Exposure time to NaOH [h] — 4 4 CA/CTAC molar ratio — 0 0.5 Total PV (by Ar 0.51 0.73 0.89 desorption) [ml/g] mesoPV [ml/g] in 2-8 nm 0.04 0.58 0.46 pore range Small mesoPV [ml/g] in 3-5 0.01 0.50 0.09 nm pore range (V.sub.s) Large mesoPV [ml/g] in 10- 0.08 0.00 0.06 50 nm pore range (V.sub.l) mesoPV/Total PV [%] 8   79 52 V.sub.s/V.sub.l 0.16 (infinite) 1.5 V.sub.s/(V.sub.s + V.sub.l) [%] 30    100 72 Argon surface area [m.sup.2/g] 750    812 670 Average pore size in 2-8 2.6  4.2 4.9 nm pore range [nm] A0 [Å], by XRD 24.27  24.30 24.32 Crystallinity (%) vs 100*    46 40 parent zeolite Y, by XRD SAR (by XRF) 83    90 89 *per definition

Preparation of Carriers and Hydrocracking Catalysts

[0089] Several hydrocracking catalysts were made. Firstly, a catalyst carrier (i.e. extruded and calcined extrudate comprising zeolite and ASA as binder) was prepared with commercially available zeolite or with the modified zeolite as prepared above, whilst using the amounts of zeolite and ASA as indicated in Table 3 below. The catalyst carriers were prepared in amounts of about 15 g. The ASA used had a surface area of 500 m.sup.2/g, a pore volume of 1.03 ml/g, an apparent bulk density of 0.24 g/ml and comprised 45% silica and 55% alumina.

[0090] As peptizing agents and extrusion aids, 1 wt. % acetic acid (Merck KGaA), 1 wt. % nitric acid (Merck KgaA), 0.5 wt. % PVA (5% aq Mowiol® 18-88) and 1 wt. % methylcellulose (K15M, available from the Dow Chemical Company) were used to prepare the carriers for making catalysts with parent zeolite (see Comparative Examples 1-4 in Table 3).

[0091] For the carriers and catalysts with modified zeolites, 2.25% nitric acid (Merck KgaA), 0.5 wt. % PVA (5% aq Mowiol® 18-88) and 1 wt. % methylcellulose (K15M) was used.

[0092] After mixing the zeolites with the ASA, a shaped catalyst carrier was obtained by extrusion into trilobe shaped extrudate with a diameter of 1.6 mm. The obtained shaped catalyst carriers were calcined at 650° C. for 1 hour.

[0093] Subsequently, the hydrogenation components were added to the calcined catalyst carriers through aqueous incipient wetness impregnation.

[0094] For the non-noble metal catalysts an impregnation solution of nickel carbonate (commercially available from Umicore (Belgium), ammonium metatungstate (commercially available from Sigma-Aldrich) and citric acid (VWR Chemicals) was used. The citric acid and Ni were added in a 1:1 molar ratio, aiming for a loading of 4 wt. % Ni and 19 wt. % W. After drying at 120° C., the catalysts were calcined at 450° C. for 2h.

[0095] For the noble metal catalysts an impregnation solution of platinum tetra-ammonium nitrate (commercially available from Heraeus, Germany) was used, aiming for a loading of 0.7 wt. % Pt. After drying at 120° C., the catalysts were calcined at 450° C. for 2 h.

TABLE-US-00003 TABLE 3 Catalysts Zeolite Y ASA content (in content (in Carrier and Hydrogenation catalyst catalyst catalyst metal (modified) carrier) carrier) preparation [wt. %] zeolite Y used [wt. %] [wt. %] Comp. Ex. 1 4% Ni/19% W CBV-780 (parent) 5 95 Comp. Ex. 2 4% Ni/19% W CBV-780 (parent) 15 85 Comp. Ex. 3 0.7% Pt CBV-780 (parent) 5 95 Comp. Ex. 4 0.7% Pt CBV-780 (parent) 15 85 Comp. Ex. 5 4% Ni/19% W MZ1 10 90 Comp. Ex. 6 4% Ni/19% W MZ2 10 90 Comp. Ex. 7 4% Ni/19% W MZ1-C 15 85 Ex. 1 0.7% Pt MZ1 10 90 Ex. 2 0.7% Pt MZ1-C 15 85 Ex. 3 0.7% Pt MZ2 10 90

Catalytic Testing

[0096] The hydrocracking performance of the catalysts of the present invention was assessed in a test.

[0097] In the test, a second stage of a two-stage simulation was performed in which inventive and comparative catalysts were evaluated. The testing was carried out in once-through nanoflow equipment which had been loaded with a catalyst bed comprising 0.6 ml of the test catalyst diluted with 0.6 ml Zirblast (B120; commercially available from Saint-Gobian ZirPro (France)).

[0098] NiW Catalysts

[0099] Prior to loading, the NiW catalysts were pre-sulfided in situ prior to testing through gas phase sulfidation: pre-sulfiding was performed at 15 barg in gas phase (5 vol. % H.sub.2S in hydrogen), with a ramp of 20° C./h from room temperature (20° C.) to 135° C., and holding for 12 hours before raising the temperature to 280° C., and holding again for 12 hours before raising the temperature to 355° C. again at a rate of 20° C./h. Afterwards, the reactor was allowed to cool down to room temperature, opened to air, and subsequently loaded in a nanoflow reactor using the dilution as described above.

[0100] Pt Catalysts

[0101] The Pt catalysts were loaded as calcined in the nanoflow reactor and were reduced in situ in hydrogen (100% H.sub.2, 60 barg), with a ramp of 25° C./h from room temperature (20° C.) to 150° C., and holding for 2 hours before raising the temperature to 350° C. at 50° C./h, and holding again for 8 hours before cooling to 160° C. to start wetting the catalyst with feedstock.

[0102] The test involved the contacting of a hydrocarbonaceous feedstock (a hydrotreated heavy gas oil) with the catalyst bed in a once-through operation under the following process conditions: [0103] a space velocity of 1.5 kg heavy gas oil per liter catalyst per hour (kg.l.sup.−1.h.sup.−1); [0104] a hydrogen gas/heavy gas oil ratio of 1500 Nl/kg; [0105] 50 ppmV H.sub.2S obtained by spiking the feed with Sulfrzol S54 (obtained from Lubrizol); and [0106] a total pressure of 14×10.sup.6 Pa (140 bar).

[0107] The hydrotreated heavy gas oil used had the following properties: [0108] Carbon content: 85.86 wt. % [0109] Hydrogen content: 14.14 wt. % [0110] Nitrogen (N) content: 0.3 ppmw [0111] Added Sulfrzol (0.186 g/kg sulfrzol 54) to achieve 50 ppmV H.sub.2S in the gas phase [0112] Density (70° C.): 0.812 g/ml [0113] Mono-aromatic rings: 0.75 wt. % [0114] Di+-aromatics rings: 0.68 wt. % [0115] Initial boiling point: 297° C. [0116] 50% w boiling point: 429° C. [0117] Final boiling point: 580° C. [0118] Fraction boiling below 370° C.: 11.6 wt. % [0119] Fraction boiling above 540° C.: 3.83 wt. %

[0120] Hydrocracking performance was assessed at conversion levels between 30 and 70 wt. % net conversion of feed components boiling above 370° C. The experiments were carried out at different temperatures to obtain 55 wt. % net conversion of feed components boiling above 370° C. in all experiments by interpolation. Table 4 below shows the results obtained for the catalysts as listed in Table 3 above.

TABLE-US-00004 TABLE 4 Hydrocracking performance C. Ex. 1 C. Ex. 2 C. Ex. 3 C. Ex. 4 C. Ex. 5 C. Ex. 6 C. Ex. 7 Ex. 1 Ex. 2 Ex. 3 (Modified) zeolite Y CBV-780 CBV-780 CBV-780 CBV-780 MZ1 MZ2 MZ1-C MZ1 MZ1-C MZ2 Zeolite Y content [wt. %] 5  15   5 15 10 10 15 10 15 10 Hydrogenation metal NiW NiW Pt Pt NiW NiW NiW Pt Pt Pt T required for target 364   343   348 331 368 367 362 361 354 359 conversion.sup.1 [° C.] C1-C4 [wt. %]  2.9  3.8 2.1 2.4 4.0 2.9 3.3 2.7 2.1 2.0 C5-82° C. [wt. %]  6.2  8.7 4.9 6.2 6.6 5.9 6.5 4.8 4.5 4.0 82-150° C. [wt. %] 27.8 31.9 25.8 26.8 24.2 25.7 26.3 17.8 22.5 20.4 150-370° C..sup.2 [wt. % ] 63.1 55.6 67.2 64.6 65.4 65.5 63.9 74.8 71.0 73.6 Delta MD.sup.3  0*  0* 7.9 9.4 1.5 1.8 1.3 12.6 10.3 11.8 diesel/kero ratio.sup.4  1.15  0.98 1.32 1.04 1.23 1.23 1.21 1.38 1.35 1.46 [wt. %/wt. %] k-540/k-370.sup.5  1.01  0.73 0.83 0.65 1.17 1.23 1.14 1.28 1.17 1.21 HDA mono [wt. %] 95.1 93.4 100.0 98.7 95.5 95.0 96.9 98.9 99.2 98.8 HDA di [wt. %] 98.6 97.3 100.5 99.5 99.2 98.9 99.4 100.0 100.0 99.8 HDA tri+ [wt. %] 88.9 83.7 85.6 91.7 89.9 82.9 91.2 111.2 95.4 88.0 H.sub.2 consumption [wt. %]  0.86  0.93 0.85 0.88 0.88 0.82 0.92 0.83 0.83 0.86 .sup.1Hydrocracking test. Target net conversion is 55 wt. %. .sup.2Middle Distillate (MD) selectivity .sup.3Delta MD versus reference curve *per definition: a linear curve between the two reference data points for the catalysts made with CBV-780 was used to calculate the delta MD for the comparative (Comparative Examples 3-7) and inventive catalysts (Examples 1-3) versus the reference (Comparative Examples 1-2) .sup.4250-370° C./150-250° C. .sup.5ratio of rate of conversion (in kg/l/h) of >540° C. fraction vs >370° C. fraction

[0121] The results in Table 4 show that: [0122] Comparative Examples 1 and 2 versus Comparative Examples 3 and 4 show the significant impact in MD selectivity of switching from a non-noble metal system (viz. sulfided NiW) to a noble metal catalyst (viz. Pt): a large delta in MD selectivity is observed. [0123] Comparative Examples 5-7 show the benefit in MD selectivity of using a zeolite with increased mesoporosity over parent zeolite (Comparative Examples 1 and 2). [0124] Examples 1 and 2 show a surprisingly high MD selectivity when combining the use of a zeolite with increased mesoporosity and a noble metal catalyst, which is larger than expected on the basis of the sum of Delta MDs: as an example, Example 1 (containing noble metal and zeolite with increased mesoporosity) shows a Delta MD of 12.6, which is significantly higher than the sum of Delta MDs for the use of noble metal (Comparative Example 3: 7.9) and zeolite with increased mesoporosity (Comparative Example 5: 1.5). [0125] The benefit of leaving the surfactant in the zeolite until and including the catalyst carrier preparation (i.e. the ‘shaping’ of step c) is shown clearly in comparison with the catalysts made with the pre-calcined zeolite (wherein a calcination step takes place before shaping). For the catalysts of both Example 1 (Pt) and Comparative Example 5 (NiW), a higher delta MD (Ex.1: 12.6; C.Ex.5: 1.5) was observed compared to catalysts made with mesoporous zeolite which was calcined directly after mesopores had been introduced: see Ex.2 (10.3) and C.Ex.7 (1.3), respectively. [0126] For the catalysts made with a larger average pore size (see Table 2) i.e. using zeolite MZ2) a similar benefit of using Pt and mesoporous zeolite was found (Ex. 3: delta MD=11.8), larger than the sum of the benefit of either Pt or application of a mesoporous zeolite prepared with swelling agent (C.Ex.6; delta MD=1.8). The reason for the benefit in the catalyst with swelling agent is currently not understood.

[0127] The person skilled in the art will readily understand that many modifications may be made without departing from the scope of the invention.