Hydrocarbon conversion catalysts

Abstract: Composition of matter suitable as catalyst base in hydroprocessing comprising a crystalline aluminosilicate of the zeolite Y type, a binder and a dispersion of silica-alumina in an alumina matrix, wherein the composition comprises less than 25% by weight of the zeolite Y, more than 25% by weight of binder and at least 30% by weight of the dispersion. The invention further relates to hydroconversion catalysts and processes based on such hydroconversion catalysts.

Description: The present invention relates to hydrocarbon conversion processes and catalyst compositions which can suitably be used in such processes, in particular hydrocracking processes. The present invention also relates to compositions of matter suitable as catalyst base in hydroprocessing. Of the many hydroconversion processes known in the art, hydrocracking is becoming increasingly important since it offers product flexibility together with product quality. As it is also possible to subject rather heavy feedstocks to hydrocracking it will be clear that much attention has been devoted to the development of hydrocracking catalysts. Whereas in the past catalytic hydrocracking was aimed primarily at the production of lower boiling points products such as gasoline, nowadays hydrocracking is often aimed at meeting the increasing demand for high quality middle distillate products. Therefore, the object in nowadays hydrocracking is to provide a hydrocracking catalyst having a high selectivity towards middle distillates and in addition a high activity and stability. To this end modern hydrocracking catalysts are generally based on zeolitic materials which may have been adapted by techniques like ammonium-ion exchange and various forms of calcination in order to improve the performance of the hydrocracking catalysts based on such zeolitic materials. One of the zeolites which is considered to be a good starting material for the manufacture of hydrocracking catalysts is the well-known synthetic zeolite Y as described in US-A-3,130,007. A number of modifications has been reported for this material which include, inter alia, ultrastable Y (US-A-3,536,605) and ultra-hydrophobic Y (GB-A-2,014,970). In general, it can be said that the modifications cause a reduction in the unit cell size depending on the treatment carried out. EP-B-70,824, for instance, is directed to the application of hydrocracking catalysts comprising a specific type of ultrahydrophobic Y zeolites, in particular a zeolite known as LZ-10. Such hydrocracking catalysts contain apart from these specific zeolites having a characteristic water adsorption capacity of less than 8% by weight of zeolite, a dispersion of silica-alumina particles in a gamma-alumina matrix and a small amount of binder, if present at all. The type of catalyst described in EP-B-70,824 is claimed to constitute an improvement over the non-zeolitic catalyst comprising a similar dispersion as described in US-A-4,097,365. Surprisingly, it has now been found that hydrocracking catalysts comprising a small amount of zeolite and a substantial amount of binder perform even more attractively in terms of selectivity and stability than the hydrocracking catalysts known so far, whilst substantially maintaining activity. Accordingly, the present invention relates to a composition of matter suitable as catalyst base in hydroprocessing comprising a crystalline aluminosilicate of the zeolite Y type which comprises a modified Y zeolite having a unit cell size below 2.437 nm, a water adsorption capacity (at 25 °C and p/p o value of 0.2) of at least 8% by weight of modified 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; an inorganic oxide binder selected from alumina, silica, magnesia, titania, clays, zirconia, silica-zirconia and silica-boria; and a dispersion of silica-alumina in an alumina matrix; wherein the composition comprises less than 25% by weight of the zeolite Y, more than 25% by weight of binder and at least 30% by weight of the dispersion. Suitably, the composition of matter according to the present invention comprises at least 30% by weight of binder. Preference is given to compositions of matter comprising less than 15% by weight of the zeolite Y. Preferably, the composition of matter has a binder/zeolite Y weight ratio in the range of 2-40. Suitably, the composition of matter according to the present invention comprises 40-70% by weight of the dispersion. Suitably, the alumina matrix comprises a transitional alumina matrix, preferably a gamma-alumina matrix. The compositions of matter in accordance with the present invention are particularly useful in certain hydroconversion processes, in particular hydrocracking processes. The inorganic oxide binder present in the compositions of matter according to the present invention may be amorphous or crystalline. Preferred binders are alumina, silica, silica-zirconia and silica-boria, more preferably alumina. The composition of matter according to the present invention comprises a crystalline aluminosilicate comprising a modified Y zeolite having a unit cell size below 2.437 nm, a water adsorption capacity (at 25 °C and p/p o value of 0.2) of at least 8% by weight of modified 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. A suitable type of such a modified Y zeolite has been described in detail in EP-B-247679. Preferably, between 10% and 40% of the total pore volume of the modified Y zeolite is made up of pores having a diameter of at least 8 nm. Preferably, the modified Y zeolite has a unit cell size below 2.435 nm. Suitably, the modified Y zeolite has a water adsorption capacity of 8-10% by weight of modified zeolite. Preferably, the modified Y zeolite has a SiO₂/Al₂O₃ molar ratio of from 4 to 25, more preferably of from 8 to 15. The present invention further relates to a catalyst composition comprising in addition to the composition of matter as defined hereinbefore at least one hydrogenation component of a Group VIB metal and/or at least one hydrogenation component of a Group VIII metal. Suitably, the catalyst composition according to the present invention comprises one or more components of nickel and/or cobalt and one or more components of molybdenum and/or tungsten or one or more components of platinum and/or palladium. The amount(s) of hydrogenation component(s) in the catalyst composition suitably ranges between 0.05 and 10% by weight of Group VIII metal component(s) and between 2 and 40% by weight of Group VIB metal component(s), calculated as metal(s) per 100 parts by weight of total catalyst. The hydrogenation components in the catalyst composition may be in the oxidic and/or sulphidic form, in particular in the sulphidic form. If a combination of at least a Group VIB and a Group VIII metal component is present as (mixed) oxides, it will normally be subjected to a sulphiding treatment prior to proper use in hydrocracking. Suitably, the modified Y zeolite has a degree of crystallinity which is at least retained at increasing SiO₂/Al₂O₃ molar ratios. The present invention also relates to a process for converting hydrocarbon oils into products of lower average molecular weight and lower average boiling point comprising contacting a hydrocarbon oil at elevated temperature and pressure in the presence of hydrogen with a catalyst composition as described hereinbefore. Suitable process conditions for the hydroconversion process comprise temperatures between 250 and 500 °C, partial hydrogen pressures of up to 300 bar and space velocities between 0.1 and 10 kg feed per litre catalyst per hour (kg/l/hr). Gas/feed ratios between 100 and 5000 Nl/kg can suitably be applied. Preferably, the hydroconversion process is carried out at a temperature between 300 and 450 °C, a partial hydrogen pressure between 25 and 200 bar and a space velocity between 0.2 and 5 kg feed per litre catalyst per hour. Preferably, gas/feed ratios are applied between 250 and 2000 Nl/kg. Feedstocks which can suitably be subjected to a hydroconversion process using a catalyst according to the present invention comprise gas oils, deasphalted oils, coker gas oils and other thermally cracked gas oils and syncrudes, optionally originating from tar sands, shale oils, residue upgrading processes or biomass. Combinations of various feedstocks can be applied. It may be desirable to subject part or all of the feedstock to one or more (hydro)treatment steps prior to its use in the hydroconversion process. It is often convenient to subject the feedstock to a (partial) hydrotreatment. The catalyst to be applied in such a hydrotreatment is suitably an amorphous hydrocracking catalyst which contains at least one metal of Group VIB and/or at least one metal of Group VIII on an amorphous. In an attractive embodiment of such a hydrotreatment use is made of two reaction zones arranged in series whereby the complete effluent from the first reaction zone can be passed to the second reaction zone. The first reaction zone comprises a first amorphous hydrocracking catalyst as described hereinbefore and the second reaction zone comprises a second, zeolitic hydrocracking catalyst which contains at least one metal of Group VIB and/or at least one metal of Group VIII. Preferably, the zeolitic catalyst comprises a catalyst composition in accordance with the present invention. In this way a very attractive hydrotreatment of a feedstock is established. Therefore, the present invention also relates to a process for the hydrotreatment of a hydrocarbonaceous feedstock comprising contacting said feedstock in the presence of hydrogen with a first amorphous hydrocracking catalyst which contains at least one metal of Group VIB and/or at least one metal of Group VIII on an amorphous carrier in a first reaction zone passing at least part of the effluent from the first reaction zone, preferably the complete effluent, to a second reaction zone and contacting in the second reaction zone said effluent from the first reaction zone in the presence of hydrogen at elevated temperature and pressure with a second, zeolitic catalyst which comprises a crystalline alumino-silicate of the zeolite Y-type, a binder and a dispersion of silica-alumina in an alumina matrix, wherein the catalyst comprises less than 25% by weight of the zeolite Y, more than 25% by weight of binder and at least 30% by weight of the dispersion. It is evident that the first reaction zone may comprise one or more beds of the alumina-containing catalyst and also the second reaction zone may contain one or more beds of the zeolite catalyst. It is also evident that the first and second reactor zone or zones may be located in one or more reactors. Preferably, the reaction zones are arranged in a stacked-bed configuration. Suitable hydrotreatment conditions include the reaction conditions mentioned in respect of the process according to the present invention. The hydrotreatment and the process according to the present invention can also suitably be carried out in reactors in series or in a stacked-bed configuration. The reactor effluent so obtained can suitably be subjected to a further hydrocracking process, preferably to a process in accordance with the present invention. The present invention will now be illustrated by means of the following Example. Example a) Preparation of a catalyst according to the present invention. 460 g of a commercially available modified Y zeolite having a unit cell size of 2.434 nm, a SiO₂/Al₂O₃ molar ratio of 9.3, a water adsorption capacity (at 25 °C and a p/p₀ value of 0.2) of 12.5% by weight and a nitrogen pore volume of 0.45 ml/g wherein 26% of the total pore volume is made up of pores having a diameter of at least 8 nm and a loss of ignition of 13% by weight was mixed with 8920 gram of an amorphous 45/55 silica-alumina (ex-Criterion) and 4110 g of hydrated aluminium oxide (ex-Criterion). To this mixture was added water and 500 g of acidic acid. After mulling, the mixture was further mixed with 300 g of extrusion aids. The resulting mixture was extruded and the extrudates obtained were dried whilst rotating for about 4 hours at 250 °C and calcined for 3 hours at 600 °C. The extrudates obtained had a water pore volume of 0.786 ml/g and a diameter of 1.65 mm. The ready catalyst support contained 4% by weight of modified Y zeolite, 30% by weight of binder and 66% by weight of the dispersion, on a dry basis. A nickel/tungsten solution was made up containing 400 g of nickel nitrate solution (14% by weight of nickel) and 670 g of ammoniummetungstate (39.8% by weight of tungsten). The nickel/tungsten solution was diluted with water to 760 ml and used to impregnate 1 kg of the extrudates described hereinabove. After homogenizing the impregnated extrudates for 1 hour using a mixer, the extrudates were dried whilst rotating for about 4 hours at 250 °C and finally calcined at 450 °C for 2 hours. They contained 3.9% by weight of nickel and 18.9 % by weight of tungsten. b) Hydrocracking experiment. The catalyst was subjected to a hydrocracking performance test involving a hydrotreated heavy vacuum gas oil having the following properties: C (%wt) 86.28 H (%wt) 13.70 S (ppm) 79 N (ppm) 15 d (70/4) 0.8496 pour point (°C) 44 I.B.P. (°C) 344 10% wt rec. 384 20% wt rec. 412 30% wt rec. 428 40% wt rec. 446 50% wt rec. 462 60% wt rec. 483 70% wt rec. 502 80% wt rec. 526 90% wt rec. 559 F.B.P. greater than 620 The catalyst was firstly subjected to a presulphiding treatment by slowly heating in a 5 %v H₂S/H₂-atmosphere to a temperature of 370 °C. The catalyst was tested in a 1:1 dilution with 0.1 mm SiC particles under the following operating conditions: WHSV of 1.5 kg/l/h, H₂S partial pressure of 2.5 bar, total pressure of 140 bar and a gas/feed ratio of 1500 Nl/kg. The experiment was carried out in once-through operation. The catalyst performance is expressed at 65 % by weight conversion of 370 °C⁺ boiling point material in the feed after allowing the catalyst to stabilize. The following results were obtained with the catalyst: Temperature required (65 % conv. of 370 °C⁺): 370 °C Middle distillate selectivity (%wt) : 61 From the above results it will be clear that attractive results can be obtained with a catalyst containing a small amount of a zeolitic component and a large amount of binder. Also the catalyst was remarkably stable, in particular in respect of the large amount of binder present. Catalysts containing an amount of less than 25% by weight of binder are less selective and stable.

Claims: Composition of matter suitable as catalyst base in hydroprocessing comprising a crystalline aluminosilicate of the zeolite Y type which comprises a modified Y zeolite having a unit cell size below 2.437 nm, a water adsorption capacity (at 25 °C and p/p o value of 0.2) of at least 8% by weight of modified 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; an inorganic oxide binder selected from alumina, silica, magnesia, titania, clays, zirconia, silica-zirconia and silica-boria; and a dispersion of silica-alumina in an alumina matrix; wherein the composition comprises less than 25% by weight of the zeolite Y, more than 25% by weight of binder and at least 30% by weight of the dispersion. Composition according to claim 1, wherein the composition comprises at least 30% by weight of binder. Composition according to claim 1 or 2, wherein the composition comprises less than 15% by weight of the zeolite Y. Composition according to claim 3, wherein the composition of matter has a binder/zeolite Y weight ratio of 2 to 40. Composition according to any one of claims 1 to 4, wherein between 10% and 40% of the total pore volume of the modified Y zeolite is made up of pores having a diameter of at least 8 nm. Composition according to any one of claims 1 to 5, wherein the modified Y zeolite has a unit cell size of below 2.435 nm. Composition according to any one of claims 1 to 6, wherein the modified Y zeolite has a water adsorption capacity of 8-10% by weight of modified zeolite. Composition according to any one of claims 1 to 7, wherein the modified Y zeolite has a SiO₂/Al₂O₃ molar ratio of from 4 to 25. Catalyst composition comprising a composition of matter according to any one of claims 1 to 8 and at least one hydrogenation component of a Group VIB metal and/or at least one hydrogenation component of a Group VIII metal. Catalyst composition according to claim 9, wherein the hydrogenation component comprises one or more components of nickel and/or cobalt and one or more components of molybdenum and/or tungsten or one or more components of platinum and/or palladium. Process for converting hydrocarbon oils into products of lower average molecular weight and lower average boiling point comprising contacting a hydrocarbon oil at elevated temperature and pressure with hydrogen in the presence of a catalyst composition according to claim 9 or 10. Process according to claim 11, which is carried out at a temperature in the range of from 250 °C to 500 °C, a hydrogen partial pressure up to 300 bar and a space velocity between 0.1 and 10 kg feed per litre of catalyst per hour.

Inventors: MINDERHOUD JOHANNES KORNELIS, STORK WILLEM HARTMAN JURRIAAN, VAN VEEN JOHANNES ANTHONIUS RO, MINDERHOUD, JOHANNES KORNELIS, STORK, WILLEM HARTMAN JURRIAAN, VAN VEEN, JOHANNES ANTHONIUS ROBERT
Applicants: SHELL INT RESEARCH, SHELL INTERNATIONALE RESEARCH MAATSCHAPPIJ B.V.
Application year: 1992
Main classification: B01J29
IPC codes: C10G47, C10G45, B01J21, B01J29, C10G49