FR3133389A1 - HYDROCRACKING CATALYST COMPRISING TWO ZEOLITHES, ONE OF WHICH IS SPECIFIC FOR THE PRODUCTION OF NAPHTHA - Google Patents

Abstract

The invention describes a hydrocracking catalyst selective towards the naphtha cut and the hydrocracking process using said catalyst, said catalyst comprising at least one hydro-dehydrogenating element chosen from the group formed by the elements of group VIB and group VIII non noble taken alone or as a mixture of the periodic classification, and a support comprising at least one porous mineral matrix, a first zeolite Y having an initial crystal parameter a0 of the unit cell greater than 24.42 Å and a second zeolite Y having a parameter initial crystalline a0 of the unit cell strictly less than 24.40 Å, a BET specific surface area between 700 and 1000 m2/g, a microporous volume determined by nitrogen adsorption greater than 0.28 ml/g and a Brønsted acidity greater than 300 micromole/g.

Description

HYDROCRACKING CATALYST COMPRISING TWO ZEOLITHES, ONE OF WHICH IS SPECIFIC FOR THE PRODUCTION OF NAPHTHA Field of the invention

The invention relates to a hydrocracking catalyst comprising two USY zeolites as well as its use for the production of naphtha by hydrocracking of petroleum cuts such as vacuum distillates and gas oil. This type of process is particularly used in schemes intended for the conversion of hydrocarbon feedstocks for the production of petrochemical intermediates and gasoline fuels.

Hydrocracking catalysts are generally classified on the basis of the nature of their acid function, in particular catalysts comprising an amorphous acid function of the silica alumina type and catalysts comprising a zeolite cracking function such as zeolite Y or zeolite beta.

Hydrocracking catalysts are also classified based on the majority product obtained when used in a hydrocracking process, the two main products being middle distillates and naphtha.

By naphtha or naphtha cut is meant the petroleum fraction having a boiling point lower than the middle distillate cut. The middle distillates cut generally has a cut point between 150°C and 370°C to maximize kerosene and diesel production. However, in the case of a process oriented specifically to the production of naphtha for example, the lower cut point of the middle distillate cut can be increased to increase naphtha yields.

For this purpose, the naphtha cut can have boiling points between that of hydrocarbon compounds having 6 carbon atoms per molecule (or 68°C boiling point) up to 216°C and includes the gasoline cut.

There is strong demand for gasoline and naphtha cuts. This is why refiners have focused for several years on hydrocracking catalysts selective for the naphtha cut.

It is known to use catalysts based on FAU type zeolite to produce a naphtha cut.

Patent US7611689 (Shell) describes an FAU type Y zeolite, a catalyst comprising said zeolite, its preparation and its use in a hydrocracking process. In particular, the FAU zeolite has a mesh parameter of between 24.40 and 24.50 angstroms (Å), a silica to alumina molar ratio (SAR) of between 5 and 10, and an alkali metal content of less than 0, 15% weight. It is demonstrated that such zeolites have a high selectivity towards the naphtha cut and in particular a high selectivity towards the heavy naphtha cut, when they are used in a hydrocracking process.

Patent application WO11067258 (Shell) describes the preparation of an FAU zeolite having a mesh parameter of between 24.42 and 24.52 angstroms (Å), a silica to alumina molar ratio (SAR) of between 10 and 15, and a surface area between 910 and 1020 m2/g. the family teaches that the catalyst comprising this zeolite is particularly selective towards the naphtha cut when it is used in a process for converting hydrocarbon cuts.

Patent application WO040487988 (Shell) describes a hydrocracking process using a catalyst comprising a zeolite Y having a low mesh parameter of between 24.10 and 24.40 angstroms (Å), a silica to alumina molar ratio (SAR) greater than 12 and preferably between 20 and 100 and a BET specific surface area greater than 850 m2/g and a microporous volume greater than 0.28 ml/g. WO040487988 teaches that zeolites having a low mesh parameter are known to be selective towards middle distillate cutting but less active than zeolites having a higher mesh parameter. The catalysts comprising zeolites with a low mesh parameter according to the invention of WO040487988 nevertheless make it possible to obtain high activity combined with good selectivity in middle distillates.

Other catalysts based on zeolite Y and Beta can also be used.

Patent US7510645 (UOP) describes a hydrocracking catalyst containing a Beta zeolite and a Y zeolite, the Y zeolite having a mesh parameter of between 24.38 and 24.50 angstroms (Å), the catalyst being characterized by a ratio Y/Beta mass of between 5 and 12. The catalyst has a relatively high proportion of Y zeolite compared to the proportion of Beta zeolite. It is demonstrated that these catalysts have improved selectivity and activity compared to conventional commercial catalysts. Also disclosed is a hydrocracking process using said catalysts at high temperature and high pressure to convert a hydrocarbon feedstock into a product having a lower boiling point and molecular weight. In particular, the product obtained comprises a large proportion of boiling component in the naphtha cut temperature range (C6-216°C).

In attempting to develop a new hydrocracking catalyst selective for the naphtha cut, the applicant discovered, surprisingly, that a catalyst comprising at least one hydro-dehydrogenating element chosen from the group formed by the elements of group VIB and non-noble group VIII of the periodic classification, and a support comprising at least one porous mineral matrix, a first zeolite Y having an initial crystal parameter a0 of the unit cell greater than 24.42 Å and a second zeolite Y having an initial crystal parameter a0 of the unit cell strictly less than 24.40 Å, a BET specific surface area of between 700 and 1000 m2/g, a microporous volume determined by nitrogen adsorption greater than 0.28 ml/g and a Brønsted acidity greater than 300 micromole/g makes it possible to improve at least one of the two performance criteria, selectivity and activity, without degrading the other compared to the different catalysts of the prior art using a single zeolite.

Object of the invention

More specifically, the present invention relates to a hydrocracking catalyst selective for the naphtha cut, comprising at least one hydro-dehydrogenating element chosen from the group formed by the elements of group VIB and non-noble group VIII taken alone or as a mixture of the periodic classification, and a support comprising at least one porous mineral matrix, a first zeolite Y having an initial crystal parameter a0 of the unit cell greater than 24.42 Å and a second zeolite Y having an initial crystal parameter a0 of the unit cell strictly less than 24.40 Å, a BET specific surface area of between 700 and 1000 m2/g, a microporous volume determined by nitrogen adsorption greater than 0.28 ml/g and a Brønsted acidity greater than 300 micromole/g.

The present invention advantageously relates to a hydrocracking catalyst comprising at least one hydro-dehydrogenating element chosen from the group formed by the elements of group VIB and non-noble group VIII taken alone or as a mixture of the periodic table, and a support comprising at less a porous mineral matrix, a first zeolite Y having an initial crystal parameter a0 of the unit cell greater than 24.42 Å and a second zeolite Y having an initial crystal parameter a0 of the unit cell less than 24.40 Å, a surface specific BET between 700 and 1000 m2/g, a microporous volume determined by nitrogen adsorption greater than 0.28 ml/g and a Brønsted acidity greater than 300 micromole/g.

Another object of the present invention is a process for hydrocracking a hydrocarbon feedstock in the presence of said catalyst.

An advantage of the present invention is to provide a hydrocracking catalyst making it possible to obtain improved selectivity towards the naphtha cut when said catalyst is used in a hydrocracking process according to the invention, compared to the catalysts of the state art.

In the present invention, the selectivity of hydrocracking catalysts for naphtha production is determined during a catalytic test and corresponds to the fraction, in weight percent, of the product boiling in the naphtha cut range, i.e. say between the boiling temperature of hydrocarbon compounds having 6 carbon atoms per molecule (or 68°C boiling point) up to 216°C, relative to the total mass of product leaving the process.

According to an advantageous embodiment, the catalyst according to the invention also comprises a beta zeolite.

An advantage of the advantageous embodiment of the present invention is to provide a hydrocracking catalyst comprising said first and second Y zeolites having the specific characteristics claimed and a beta zeolite in a specific Y/beta mass ratio allowing not only the obtaining of 'improved selectivity towards the naphtha cut when said catalyst is used in a hydrocracking process according to the invention, but also improved activity compared to the catalysts of the prior art.

In the present invention, the converting activity of hydrocracking catalysts for the production of naphtha is determined during a catalytic test by comparing the temperature at which the catalyst must be operated to produce at least 65% by weight of products having a point boiling point below 216°C. The lower the required temperature, the more active the catalyst. This reduction in temperature makes it possible, for example, to limit the energy consumption of the process and to increase the cycle duration of use of the catalyst, or even to treat less reactive loads without modifying the capacity and the process flowsheet.

Throughout the remainder of the text, specific surface area is understood to mean the B.E.T specific surface area (SBET) determined by nitrogen adsorption in accordance with the ASTM 4365-19 standard established using the BRUNAUER-EMMETT-TELLER method described in the periodical “ The Journal of American Society,” 60, 309, (1938). Analysis of the texture by nitrogen adsorption also makes it possible to determine the microporous volume, i.e. volume of pores whose opening is less than 2 nm. Before analysis, the zeolite powder is activated at 500°C for 5 hours.

Throughout the remainder of the text, the initial crystal parameter a0 of the unit cell of said zeolites Y given is the value of the initial crystal parameter a0 of said zeolites Y used in the synthesis of the catalyst according to the invention.

The initial crystalline parameter a0 of the unit cell of said zeolites Y is measured by X-ray diffraction according to the ASTM 03942-80 standard.

Similarly, the volume of mesopores is determined by nitrogen adsorption. Throughout the remainder of the text, “micropores” means pores whose opening is less than 2 nm, and “mesopores” means pores whose opening is greater than 2 nm.

Throughout the remainder of the text, the Brønsted acidity of zeolite Y is measured by adsorption and subsequent thermodesorption of pyridine followed by infrared spectroscopy (FTIR). This method is conventionally used to characterize acidic solids such as Y zeolites as described in the periodical C. A. Emeis “Journal of Catalysis”, 141,347, (1993). Before analysis, the zeolite powder is compacted in the form of a 16 mm diameter pellet and is activated under secondary vacuum at 450°C. The introduction of the pyridine into the gas phase in contact with the activated pellet as well as the thermodesorption step are carried out at 150°C. The concentration of pyridinium ion detected by FTIR after thermodesorption at 150 °C corresponds to the Brønsted acidity of the zeolite and is expressed in micromole/g.

In the sense of the present invention, the different embodiments presented can be used alone or in combination with each other, without limitation of combination.

In the sense of the present invention, the different parameter ranges for a given step such as the pressure ranges and the temperature ranges can be used alone or in combination. For example, within the meaning of the present invention, a preferred range of pressure values can be combined with a more preferred range of temperature values.

In the rest of the text, the groups of chemical elements are given according to the CAS classification (CRC Handbook of Chemistry and Physics, publisher CRC press, editor-in-chief D.R. Lide, 81st edition, 2000-2001). For example, group VIII according to the CAS classification corresponds to the metals of columns 8, 9 and 10 according to the new IUPAC classification, and group VIB to the metals of column 6.

In the rest of the text, the expressions “between… and…” and “between…. and…” are equivalent and mean that the limit values of the interval are included in the range of values described. If this were not the case and the limit values were not included in the range described, such precision will be provided by the present invention.

Detailed description of the invention The hydro/dehydrogenating function

In accordance with the invention, the catalyst comprises at least one hydro-dehydrogenating element chosen from the group formed by the non-noble elements of group VIB and group VIII of the periodic table, taken alone or as a mixture.

Preferably, the elements of group VIII are chosen from iron, cobalt, nickel, taken alone or in a mixture, and preferably from nickel and cobalt. Preferably, the elements of group VIB are chosen from tungsten and molybdenum, taken alone or as a mixture. The following combinations of metals are preferred: nickel-molybdenum, cobalt-molybdenum, nickel-tungsten, cobalt-tungsten, and very preferably: nickel-molybdenum, nickel-tungsten. It is also possible to use combinations of three metals such as, for example, nickel-cobalt-molybdenum.

The group VIII element content of the catalyst is advantageously between 0.5 and 8% by weight of oxide relative to the total weight of said catalyst, preferably between 0.5 and 6% by weight of oxide and so very preferred between 1.0 and 4% by weight of oxide. The group VIB element content of the catalyst is advantageously between 1 and 30% by weight of oxide relative to the total weight of said catalyst, preferably between 2 and 25% by weight of oxide, very preferably between 5 and 20% by weight of oxide, and even more preferably between 5 and 16% by weight of oxide.

Preferably, the catalyst used according to the invention may also contain a promoter element chosen from phosphorus, boron, silicon, very preferably phosphorus. When the catalyst contains phosphorus, the phosphorus content is advantageously between 0.5 and 10% by weight of P2O5 oxide relative to the total weight of said catalyst, preferably between 1 and 6% by weight of P2O5 oxide and more preferably between 1 and 4% by weight of P2O5 oxide.

The support

The catalyst according to the invention comprises a support which comprises and is preferably constituted by at least one porous mineral matrix, a first zeolite Y having an initial crystal parameter a0 of the unit cell greater than 24.42 Å and a second zeolite Y, preferably a dealuminated USY zeolite, said second Y zeolite having an initial crystal parameter a0 of the unit cell strictly less than 24.40 Å, a BET specific surface area of between 700 and 1000 m2/g, a microporous volume greater than 0.28 ml/g and a Brønsted acidity greater than 300 micromole/g.

The porous mineral matrix used in the catalyst support, also called binder, is advantageously made up of at least one refractory oxide, preferably chosen from the group formed by alumina, silica-alumina, clay, oxide titanium, boron oxide and zirconia, taken alone or in a mixture. Preferably, the porous mineral matrix is chosen from alumina and silica-alumina, taken alone or as a mixture. More preferably, the porous mineral matrix is alumina. Alumina can advantageously be presented in all its forms known to those skilled in the art. Very preferably, the alumina is gamma alumina, for example coming from boehmite.

Preferably, said support comprises from 20 to 85% by weight of binder, preferably from 20% to 60% by weight, and very preferably between 20% and 50% by weight, relative to the total weight of said support.

According to the invention, the support comprises a first zeolite Y having an initial crystal parameter a0 of the unit cell greater than 24.42 Å.

Preferably, the initial crystal parameter a0 of the unit cell of the first zeolite Y used is between 24.42 Å and 24.70 Å, preferably greater than 24.45 Å and less than 24.70 Å, preferably greater at 24.50 Å and less than 24.70 Å, preferably between 24.52 Å and 24.70 Å and preferably between 24.52 Å and 24.65 Å, preferably between 24.52 Å and 24.60 Å and very preferably between 24.52 Å and 24.58 Å.

Preferably, said first zeolite Y has a specific surface area measured by nitrogen physisorption according to the B.E.T. method. between 700 and 1000 m2/g, preferably between 750 and 950 m2/g, and preferably between 800 and 950 m2/g.

Preferably, said first zeolite Y has a microporous volume determined by nitrogen adsorption greater than 0.28 ml/g and advantageously less than 0.34 ml/g and preferably less than 0.32 ml/g.

Preferably, said first zeolite Y has a Brønsted acidity greater than 500 micromole/g, preferably between 500 and 700 micromole/g and preferably between 550 and 650 micromole/g.

Preferably, said first zeolite Y has a silica to alumina molar ratio (SAR) of between 3 and 20 and preferably between 3 and 15 and preferably greater than 3 and less than 10.

Preferably, said support has a content of said first zeolite Y of between 1 to 69% by weight relative to the total weight of said support, preferably between 15 to 50% by weight, and preferably between 25 to 40% by weight.

According to the invention, the support also comprises a second zeolite Y having an initial crystal parameter a0 of the elementary cell strictly less than 24.40 Å.

Preferably, the initial crystal parameter a0 of the unit cell of the second zeolite Y used is less than 24.40 Å, preferably between 24.30 and 24.39 Å, preferably between 24.32 and 24.39 Å, preferably between 24.32 and 24.38 Å, and very preferably between 24.34 Å and 24.38 Å.

According to the invention, said second zeolite Y has a specific surface area measured by nitrogen physisorption according to the B.E.T. method. between 700 and 1000 m2/g, preferably between 750 and 950 m2/g, and preferably between 800 and 950 m2/g.

According to the invention, said second zeolite Y has a microporous volume determined by nitrogen adsorption greater than 0.28 ml/g and preferably greater than 0.285 ml/g and advantageously less than 0.34 ml/g.

According to the invention, said second zeolite Y has a Brønsted acidity greater than 300 micromole/g, preferably between 320 and 500 micromole/g and preferably between 325 and 425 micromole/g.

Preferably, said second zeolite Y has a silica to alumina molar ratio (SAR) of between 5 and 50 and preferably between 5 and 20 and preferably greater than 5 and less than 12.

Preferably, said second zeolite Y has a mesoporous volume greater than 0.12 ml/g, preferably greater than 0.16 ml/g and preferably between 0.18 and 0.24 ml/g.

Preferably, said support has a content of said second zeolite Y, and preferably of said second dealuminated zeolite USY, of between 1 to 69% by weight relative to the total weight of said support, preferably between 15 to 50% by weight, and preferably between 25 to 40% by weight.

Preferably the total weight content of the USY zeolites comprising said first and second Y zeolites is between 15 and 80% by weight relative to the total weight of said support, preferably between 20 and 75% by weight and preferably between 40 and 75% by weight. .

Preferably, the weight ratio of said first zeolite Y to said second zeolite Y in the catalyst is between 0.015 and 69, preferably between 1 and 40, preferably between 1 and 20, very preferably between 1 and 5.

Said zeolites are advantageously defined in the classification “Atlas of Zeolite Framework Types, 6th revised edition”, Ch. Baerlocher, L. B. Mc Cusker, D.H. Olson, 6th Edition, Elsevier, 2007, Elsevier".

According to a preferred embodiment of the invention, said zeolite Y, having the particular characteristics defined above and suitable for the implementation of the catalyst support used in the process according to the invention are advantageously prepared from a zeolite Y of structural type FAU preferably having a silica to alumina molar ratio (SAR) after synthesis of between 4.6 and 5.6 and advantageously presenting itself in NaY form after synthesis. The operating conditions of the ion exchange, dealumination and calcination stages are adapted according to the final characteristics of said desired Y zeolites.

In particular, the general preparation protocol described above and including the different steps of ion exchange, dealumination and heat treatment makes it possible to prepare both the first zeolite Y and the second zeolite Y. However, differences in the number and order of steps and the operating conditions (i.e. temperature, duration, nature and proportions of reagents, etc.) make it possible to prepare a first zeolite Y different in characteristics from the second zeolite Y.

Said zeolite Y of starting FAU structural type thus advantageously undergoes a step of one or more ionic exchanges before undergoing the dealumination step. The ion exchange(s) make it possible to partially or totally replace the alkaline cations belonging to groups IA and IIA of the periodic classification present in the cationic position in the crudely synthesized FAU structural type Y zeolite by NH4+ cations and preferably cations Na+ by NH4+ cations.

By partial or total exchange of alkaline cations with NH4+ cations is meant the exchange of 80 to 100%, preferably 85 to 99.5% and more preferably 88 to 99%, of said alkaline cations with NH4+ cations. At the end of the ion exchange step(s), the remaining quantity of alkaline cations, and preferably the remaining quantity of Na+ cations, in the zeolite Y, relative to the quantity of alkaline cations, preferably Na+, initially present in zeolite Y, is advantageously between 0 and 20%, preferably between 0.5 and 15% and preferably between 1.0 and 12%.

Preferably, this step implements several ion exchanges with a solution containing at least one ammonium salt chosen from chlorate, sulfate, nitrate, phosphate, or ammonium acetate salts, so as to eliminate at least in part, alkaline cations and preferably Na+ cations present in the zeolite. Preferably, the ammonium salt is ammonium nitrate NH4NO3.

Thus, the remaining content of alkaline cations and preferably of Na+ cations in the zeolite Y at the end of the ion exchange(s) step is preferably such that the alkaline cation/aluminum molar ratio and preferably the Na/Al molar ratio is between 0:1 and 0:1, preferably between 0:1 and 0.005:1, and more preferably between 0:1 and 0.008:1.

The desired alkaline cation/aluminum ratio, preferably Na/Al, is obtained by adjusting the NH4+ concentration of the ion exchange solution, the ion exchange temperature and the number of ion exchanges. The concentration of the NH4+ ion exchange solution advantageously varies between 0.01 and 12 mol.L-1, and preferably between 1.00 and 10 mol.L-1. The temperature of the ion exchange step is advantageously between 20 and 100°C, preferably between 60 and 95°C, preferably between 60 and 90°C, more preferably between 60 and 85°C and even more preferably between 60 and 80°C. The number of ion exchanges advantageously varies between 1 and 10 and preferably between 1 and 4.

Said zeolite Y, preferably of structural type FAU, obtained can then undergo a dealumination treatment step. Said dealumination step can advantageously be carried out by all the methods known to those skilled in the art. Preferably, the dealumination is carried out by a heat treatment optionally in the presence of water vapor (or steaming according to Anglo-Saxon terminology) and/or by one or more acid attacks advantageously carried out by treatment with an aqueous acid solution. mineral or organic.

Preferably, the dealumination step implements a heat treatment followed by one or more acid attacks, or only one or more acid attacks.

Preferably, the heat treatment optionally in the presence of water vapor to which said zeolite Y is subjected is carried out at a temperature between 200 and 900°C, preferably between 300 and 900°C, even more preferably between 400 and 900°C. 750°C. The duration of said heat treatment is advantageously greater than or equal to 0.5 h, preferably between 0.5 h and 24 h, and very preferably between 1 h and 12 h. In the case where the heat treatment is carried out in the presence of water, the volume percentage of water vapor during the heat treatment is advantageously between 5 and 100%, preferably between 20 and 100%, very preferably between 40 and 100%. The volume fraction other than the water vapor possibly present is air. The gas flow rate formed of water vapor and possibly air is advantageously between 0.2 L.h-1.g-1 and 10 L.h-1.g-1 of zeolite Y.

The heat treatment makes it possible to extract the aluminum atoms from the framework of the zeolite Y while maintaining the overall Si/Al atomic ratio of the treated zeolite unchanged.

The heat treatment step in the presence of water vapor can advantageously be repeated as many times as is necessary to obtain the dealuminated Y zeolite USY suitable for the implementation of the catalyst support used in the process according to the invention and having a crystal parameter a0 of the unit cell strictly less than 24.40 Å.

The heat treatment step possibly in the presence of water vapor is advantageously followed by an acid attack step. Said acid attack makes it possible to eliminate partially or entirely the aluminum debris resulting from the heat treatment step in the presence of water vapor and which partially blocks the porosity of the dealuminated zeolite; the acid attack therefore makes it possible to unclog the porosity of the dealuminated zeolite.

The acid attack can advantageously be carried out by suspending the zeolite Y, which has optionally previously undergone heat treatment, in an aqueous solution containing a mineral or organic acid. The mineral acid can be nitric acid, sulfuric acid, hydrochloric acid, phosphoric acid or boric acid. The organic acid may be formic acid, acetic acid, oxalic acid, tartaric acid, maleic acid, malonic acid, malic acid, lactic acid, or any other acid. organic soluble in water. The concentration of the solution of mineral or organic acid in the solution advantageously varies between 0.01 and 2.0 mol.L-1, and preferably between 0.5 and 1.0 mol.L-1. The temperature of the acid attack step is advantageously between 20 and 100°C, preferably between 60 and 95°C, preferably between 60 and 90°C and more preferably between 60 and 80°C. The duration of the acid attack is advantageously between 5 minutes and 8 hours, preferably between 30 minutes and 4 hours, and preferably between 1 hour and 2 hours.

At the end of the heat treatment step(s) optionally in the presence of water vapor and possibly the acid attack step, the method of modifying said zeolite Y advantageously comprises a step of at least one partial exchange or total of the alkaline cations and preferably the Na+ cations still present in the cationic position in the zeolite Y. The ion exchange step is carried out in a manner similar to the ion exchange step described above.

At the end of the heat treatment step(s) optionally in the presence of water vapor and optionally of the acid attack step and optionally of the step of partial or total exchange of alkaline cations and preferably cations Na+, the process for modifying said zeolite Y may include a calcination step. Said calcination makes it possible to eliminate the organic species present within the porosity of the zeolite, for example those provided by the acid attack step or by the partial or total exchange step of the alkaline cations. In addition, said calcination step makes it possible to generate the protonated form of zeolite Y and to give it acidity for its applications.

The calcination can advantageously be carried out in a muffle furnace or in a tubular furnace, under dry air or under an inert atmosphere, in a licked bed or in a crossed bed. The calcination temperature is advantageously between 200 and 800°C, preferably between 450 and 600°C, and preferably between 500 and 550°C. The duration of the calcination stage is advantageously between 1 and 20 hours, preferably between 6 and 15 hours, and preferably between 8 and 12 hours.

Thus, said first zeolite Y obtained has an initial crystal parameter a0 of the unit cell greater than 24.42 Å.

Said second zeolite Y obtained has an initial crystalline parameter a0 of the unit cell strictly less than 24.40 Å, a specific surface area measured by nitrogen physisorption according to the B.E.T. method. between 700 and 1000 m2/g, a microporous volume determined by nitrogen adsorption greater than 0.28 ml/g and a Brønsted acidity greater than 300 micromole/g.

In a preferred embodiment, the support also comprises a Beta zeolite.

Beta zeolite is generally synthesized from a reaction mixture containing a structuring agent. The use of structuring agents is well known to those skilled in the art: for example, US patent 3,308,069 describes the use of tetraethylammonium hydroxide, and US patent 5,139,759 describes the use of tetraethylammonium cation derived from a tetraethylammonium halide compound. Another standard method for preparing Beta zeolite is given in the book Verified Synthesis of Zeolitic Materials.

The Beta zeolite used in the support according to the invention preferably has a silica to alumina molar ratio (SAR) of between 10 and 100, preferably between 20 and 50, and preferably between 20 and 30. The Beta zeolite used in the support according to the invention advantageously has a specific surface area measured by nitrogen physisorption according to the B.E.T. method. between 400 and 800 m2/g, preferably between 500 and 750 m2/g, and preferably between 550 and 700 m2/g.

In the case where the support comprises a Beta zeolite, the support advantageously has a Beta zeolite content of between 2 and 40%, preferably between 5 and 35%, and preferably between 5 and 20% by weight relative to the total weight of said support.

In the case where the support comprises a beta zeolite, the weight ratio of the sum of said Y zeolites to said Beta zeolite in the catalyst is between 1 and 40.

Preferably, the weight ratio of the sum of said Y zeolites to said Beta zeolite in the catalyst is between 1 and 30, and preferably between 1.2 and 15, and preferably between 2 and 8.

This weight ratio is calculated from the dry masses of zeolites, that is to say the masses of the zeolites corrected for their water content and ammonium ion content determined by measuring Loss On Ignition at 1000 °C. (dry mass)

In the case where the support comprises only said Y zeolites (without Beta zeolite), it is preferably made up of:

- 1 to 69%, preferably 15 to 50%, and preferably 25 to 40%, by weight relative to the total weight of said support of the first zeolite Y, preferably of a dealuminated zeolite USY, having a initial crystal parameter a0 of the unit cell greater than 24.42 Å;

- 1 to 69%, preferably 15 to 50%, and preferably 25 to 40%, by weight relative to the total weight of said support of the second zeolite Y, preferably of a dealuminated zeolite USY, having a initial crystal parameter a0 of the unit cell strictly less than 24.40 Å

- from 20 to 85% by weight, preferably between 20% to 60% by weight, and very preferably between 20% and 50% by weight relative to the total weight of said support of at least one porous mineral matrix.

In the case where the support comprises said Y zeolites and a Beta zeolite, it is preferably made up of:

- 1 to 69%, preferably 15 to 50%, and preferably 25 to 40%, by weight relative to the total weight of said support of said first zeolite Y, preferably of a dealuminated zeolite USY, having a initial crystal parameter a0 of the unit cell greater than 24.42 Å;

- 1 to 69%, preferably from 15 to 50%, and preferably from 25 to 40%%, by weight relative to the total weight of said support of said second zeolite Y, preferably of a dealuminated zeolite USY, having an initial crystal parameter a0 of the unit cell strictly less than 24.40 Å

- from 2 to 40%, preferably 5 to 35%, 5 to 20% by weight relative to the total weight of said support of a Beta zeolite; And

- from 20 to 85% by weight, preferably between 205% to 60% by weight, and very preferably between 20% and 50% by weight relative to the total weight of said support of at least one porous mineral matrix.

Preferably, the catalyst has a total zeolite Y content of between 7 and 78% by weight relative to the total weight of said catalyst.

Preferably, in the case where a Beta zeolite is present in the catalyst formulation, said catalyst has a Beta zeolite content of between 2 and 39% by weight relative to the total weight of said catalyst.

Preferably, said catalyst has a content of at least one porous mineral matrix of between 4 and 81% by weight relative to the total weight of said catalyst.

The hydrocracking catalyst advantageously having a Y/beta ratio included in these ranges not only makes it possible to obtain a high selectivity towards the naphtha cut when said catalyst is used in a hydrocracking process according to the invention, but also a improved activity compared to state-of-the-art catalysts.

In particular, the catalyst according to the invention makes it possible to improve at least one of the two performance criteria, selectivity and activity, without degrading the other compared to the different catalysts of the prior art using a single zeolite.

Preparation of the catalyst

The catalyst is advantageously prepared according to the conventional methods used in the prior art.

In particular, the catalyst is prepared according to a preparation process comprising:

- a support preparation step comprising:

• the mixture of at least one porous mineral matrix with a first zeolite Y having an initial crystal parameter a0 of the unit cell greater than 24.42 Å, a second zeolite Y having an initial crystal parameter a0 of the unit cell strictly less than 24 .40 Å, a specific surface area measured by nitrogen physisorption using the B.E.T. method. between 700 and 1000 m2/g, a microporous volume determined by nitrogen adsorption greater than 0.28 ml/g and a Brønsted acidity greater than 300 micromole/g, and, in the advantageous embodiment where a Beta zeolite is present, with a Beta zeolite, the weight ratio of said Y zeolite to said Beta zeolite in the catalyst being between 1 and 40 and
• shaping said mixture;

- the introduction of at least one hydro-dehydrogenating element chosen from the group formed by the elements of group VIB of the periodic table, preferably molybdenum and tungsten, the elements of non-noble group VIII of the periodic table, preferably iron, cobalt, nickel, and their mixtures, and preferably nickel and cobalt, and their mixtures, on the support by:

• addition of at least one precursor of said element during shaping so as to introduce at least part of said element,
• impregnation of the support with at least one precursor of said element,

- possibly a drying and/or calcination step following the preparation of the support and/or the step of introducing at least one hydro-dehydrogenating element.

More particularly, the catalyst is prepared according to a preparation process comprising the following steps:

a) preparation of the first zeolite Y, preferably dealuminated zeolite USY having the above characteristics,

b) preparation of the second zeolite Y, preferably dealuminated zeolite USY having the above characteristics,

c) preparation of the Beta zeolite in the case where a beta zeolite is present in the formulation of the catalyst according to the invention,

d) mixing with a porous mineral matrix and shaping to obtain the support,

e) introduction of at least one hydro-dehydrogenating element onto the support by at least one of the following methods:

• addition of at least one precursor of said element during shaping so as to introduce at least part of said element,
• impregnation of the support with at least one precursor of said hydro-dehydrogenating element,

Possibly drying and/or calcination of the products obtained at the end of each of the preparation steps a) or b) or c) or d) or e).

The support can advantageously be shaped by any technique known to those skilled in the art. The shaping can be carried out for example by extrusion, by pelletizing, by the oil-drop coagulation method, by granulation on a turntable or by any other method well known to those skilled in the art.

The support is preferably shaped in the form of grains of different shapes and dimensions. They are generally used in the form of cylindrical or polylobed extrudates such as trilobes, quadrilobes or polylobes of straight or twisted shape, but can optionally be manufactured and used in the form of crushed powders, tablets, rings, balls, wheels. It is however advantageous for the catalyst to be in the form of extrudates with a diameter of between 0.5 and 5 mm and more particularly between 0.7 and 3 mm and even more particularly between 1.0 and 2.5 mm. The shapes are cylindrical (which can be hollow or not), twisted cylindrical, multilobed (2, 3, 4 or 5 lobes for example), rings. Any other form can be used.

One of the preferred shaping methods consists of co-kneading said zeolites with the binder, preferably alumina, in the form of a wet gel for a few tens of minutes, preferably between 10 and 40 minutes, then passing the paste as well. obtained through a die to form extrudates with a diameter preferably between 0.5 and 5 mm.

According to another of the preferred shaping methods, said zeolites can be introduced during the synthesis of the porous mineral matrix. For example, according to this preferred mode of the present invention, said Y and Beta zeolites are added during the synthesis of a porous mineral matrix, such as for example a silico-aluminum matrix: in this case, said zeolites can advantageously be added to a mixture composed of an alumina compound in an acid medium with a completely soluble silica compound.

The introduction of the elements of group VIB and/or VIII can optionally take place during the shaping step, by addition of at least one compound of said element, so as to introduce at least a part of said element.

The introduction of at least one hydro-dehydrogenating element can advantageously be accompanied by that of at least one promoter element chosen from phosphorus, boron, silicon and preferably phosphorus and optionally by the introduction of an element from the group VIIA and/or VB. The shaped solid is optionally dried at a temperature of between 60 and 250°C and optionally calcined at a temperature of 250 to 800°C for a period of between 30 minutes and 6 hours.

The step of introducing at least one hydro-dehydrogenating element is advantageously carried out by a method well known to those skilled in the art, in particular by one or more operations of impregnation of the shaped and calcined or dried support, and preferably calcined, with a solution containing the precursors of the elements of group VIB and/or VIII, optionally the precursor of at least one promoter element and optionally the precursor of at least one element of group VIIA and/or group VB .

Preferably, said step d) is carried out by a dry impregnation method with a solution containing the precursors of the hydro/dehydrogenating function, that is to say elements of group VIB and/or VIII, optionally followed by a drying step and preferably without a calcination step.

In the case where the catalyst of the present invention contains a non-noble metal from group VIII, the metals from group VIII are preferably introduced by one or more operations of impregnation of the shaped and calcined support, after those of group VIB or at the same time as these.

The introduction of at least one hydro-dehydrogenating element can then optionally be followed by drying at a temperature between 60 and 250°C and optionally by calcination at a temperature between 250 and 800°C.

The sources of molybdenum and tungsten are advantageously chosen from oxides and hydroxides, molybdic and tungstic acids and their salts, in particular ammonium salts such as ammonium molybdate, ammonium heptamolybdate, tungstate d ammonium, phosphomolybdic acid, phosphotungstic acid and their salts, silicomolybdic acid, silicotungstic acid and their salts. Ammonium oxides and salts such as ammonium molybdate, ammonium heptamolybdate and ammonium tungstate are preferably used.

The sources of non-noble group VIII elements which can be used are well known to those skilled in the art. For example, for non-noble metals we will use nitrates, sulfates, hydroxides, phosphates, halides such as chlorides, bromides and fluorides, carboxylates such as acetates and carbonates.

The preferred source of phosphorus is orthophosphoric acid H3PO4, but its salts and esters such as ammonium phosphates are also suitable. Phosphorus can for example be introduced in the form of a mixture of phosphoric acid and a basic organic compound containing nitrogen such as ammonia, primary and secondary amines, cyclic amines, compounds of the pyridine and quinoline family and compounds of the pyrrole family. Tungsto-phosphoric or tungsto-molybdic acids can be used.

The phosphorus content is adjusted, without limiting the scope of the invention, in such a way as to form a mixed compound in solution and/or on the support, for example tungsten-phosphorus or molybdenum-tungsten-phosphorus. These mixed compounds may be heteropolyanions. These compounds can be Anderson heteropolyanions, for example.

The source of boron can be boric acid, preferably orthoboric acid H3BO3, ammonium biborate or pentaborate, boron oxide, boric esters. Boron can for example be introduced in the form of a mixture of boric acid, hydrogen peroxide and a basic organic compound containing nitrogen such as ammonia, primary and secondary amines, cyclic amines, compounds from the pyridine and quinoline family and compounds from the pyrrole family. Boron can be introduced for example by a solution of boric acid in a water-alcohol mixture.

Many sources of silicon can be used. Thus, one can use ethyl orthosilicate Si(OEt)4, siloxanes, polysiloxanes, silicones, silicone emulsions, halide silicates such as ammonium fluorosilicate (NH4)2SiF6 or fluorosilicate of sodium Na2SiF6. Silicomolybdic acid and its salts, silicotungstic acid and its salts can also be advantageously used. Silicon can be added, for example, by impregnation of ethyl silicate dissolved in a water-alcohol mixture. Silicon can be added for example by impregnation of a silicon compound of the silicone type or silicic acid suspended in water.

The sources of group VB elements which can be used are well known to those skilled in the art. For example, among the sources of niobium, oxides can be used, such as diniobium pentaoxide Nb2O5, niobic acid Nb2O5.H2O, niobium hydroxides and polyoxoniobates, niobium alkoxides of formula Nb(OR1)3 where R1 is an alkyl radical, niobium oxalate NbO(HC2O4)5, ammonium niobate. Niobium oxalate or ammonium niobate are preferably used.

The sources of group VIIA elements which can be used are well known to those skilled in the art. For example, fluoride anions can be introduced in the form of hydrofluoric acid or its salts. These salts are formed with alkali metals, ammonium or an organic compound. In the latter case, the salt is advantageously formed in the reaction mixture by reaction between the organic compound and the hydrofluoric acid. It is also possible to use hydrolyzable compounds that can release fluoride anions into water, such as ammonium fluorosilicate (NH4)2SiF6, silicon SiF4 or sodium tetrafluoride Na2SiF6. Fluorine can be introduced, for example, by impregnation with an aqueous solution of hydrofluoric acid or ammonium fluoride.

Hydrocracking process

The catalyst according to the invention is then advantageously used in a hydrocracking process, in particular for the production of naphtha. The catalyst used in a hydrocracking process, such as the process according to the invention, can advantageously be in sulfurized form. The non-noble group VIB and/or group VIII metals of said catalyst are therefore present in sulfide form.

The catalysts used in the processes according to the present invention are then advantageously subjected beforehand to a sulfurization treatment making it possible to transform, at least in part, the metal species into sulfurized form before they are brought into contact with the load to be treated. This activation treatment by sulfurization is well known to those skilled in the art and can be carried out by any method already described in the literature either in-situ, that is to say in the reactor, or ex-situ.

A classic sulfidation method well known to those skilled in the art consists of heating the catalyst in the presence of hydrogen sulfide (pure or for example under a flow of a mixture of hydrogen-hydrogen sulfide) to a temperature between 150 and 800 °C, preferably between 250 and 600 °C, generally in a cross-bed reaction zone.

Another subject of the present invention also relates to a process for hydrocracking at least one hydrocarbon feedstock, preferably in liquid form, of which at least 50% by weight of the compounds have an initial boiling point greater than 300°C. and a final boiling point below 650°C, at a temperature between 200°C and 480°C, at a total pressure between 1 MPa and 25 MPa, with a ratio of volume of hydrogen per volume of hydrocarbon feedstock between 80 and 5000 liters per liter and at an Hourly Volume Velocity (VVH) defined by the ratio of the volume flow of hydrocarbon feed, preferably liquid, to the volume of catalyst loaded into the reactor of between 0.1 and 50 h- 1, in the presence of the catalyst according to the invention.

Advantageously, the catalyst according to the invention is used in the hydrocracking process according to the invention after a so-called pretreatment section containing one or more hydrotreatment catalyst(s) which may be any catalyst known to those skilled in the art. and which makes it possible to reduce the content of certain contaminants in the load (see below) such as nitrogen, sulfur or metals. The operating conditions (VVH, temperature, pressure, hydrogen flow, liquid, reaction configuration, etc.) of this so-called pretreatment section can be diverse and varied in accordance with the knowledge of those skilled in the art.

Charges

A wide variety of feeds can be treated by the hydrocracking processes according to the invention. The feed used in the hydrocracking process according to the invention is a hydrocarbon feed of which at least 50% by weight of the compounds have an initial boiling point greater than 300 °C and a final boiling point less than 650 °C. C, preferably of which at least 60% by weight, preferably of which at least 75% by weight and more preferably of which at least 80% by weight of the compounds, have an initial boiling point greater than 300 ° C and a point of final boiling point below 650°C.

The feed is advantageously chosen from LCO (Light Cycle Oil, light gas oils from a catalytic cracking unit), atmospheric distillates, vacuum distillates such as for example gas oils from direct distillation of crude or from units of conversion such as FCC, coker or visbreaking, feeds from units for extracting aromatics from lubricating oil bases or from solvent dewaxing of lubricating oil bases, distillates from desulfurization processes or fixed bed or bubbling bed hydroconversion of RAT (atmospheric residues) and/or RSV (vacuum residues) and/or deasphalted oils, and deasphalted oils, paraffins from the Fischer-Tropsch process, taken alone or in mixture. We can cite fillers from renewable origins (such as vegetable oils, animal fats, hydrothermal conversion oil or lignocellulosic biomass pyrolysis oil) as well as plastic pyrolysis oils. The list above is not exhaustive. Said fillers preferably have a boiling point T5 greater than 300°C, preferably greater than 340°C, that is to say that 95% of the compounds present in the filler have a boiling point greater than 300°C , and preferably greater than 340°C.

The nitrogen content of the feeds treated in the processes according to the invention is advantageously greater than 500 ppm by weight, preferably between 500 and 10000 ppm by weight, more preferably between 700 and 4000 ppm by weight and even more preferably between 1000 and 4000 ppm weight. The sulfur content of the charges treated in the processes according to the invention is advantageously between 0.01 and 5% by weight, preferably between 0.2 and 4% by weight and even more preferably between 0.5 and 3% by weight. % weight.

The filler may possibly contain metals. The cumulative nickel and vanadium content of the charges treated in the processes according to the invention is preferably less than 1 ppm by weight.

The filler may possibly contain asphaltenes. The asphaltene content is generally less than 3000 ppm by weight, preferably less than 1000 ppm by weight, even more preferably less than 200 ppm by weight.

Advantageously, when the catalyst according to the invention is used after a hydrotreatment section as described above, the content of nitrogen, sulfur, metals or asphaltenes of the liquid injected into the process according to the invention implementing the catalyst according to the invention is reduced. Preferably, the organic nitrogen content of the feed treated in the hydrocracking process according to the invention is then comprised, after hydrotreatment, between 0 and 200 ppm, preferably between 0 and 50 ppm, and even more preferably between 0 and 30 ppm. The sulfur content is preferably less than 1000 ppm and that of asphaltene is preferably less than 200 ppm while the metal content (Ni or V) is less than 1 ppm.

The hydrocracking process according to the invention may comprise a fractionation step between the pretreatment of the feed and the hydrocracking reactor(s) using the catalyst according to the invention. In the preferred case where the hydrocracking process is operated without fractionation (gas and liquid) between the pretreatment and the hydrocracking reactor(s) using the catalyst according to the invention, the nitrogen and the sulfur eliminated liquid after the pretreatment is injected in the form of NH3 and H2S into the reactor(s) containing the catalyst according to the invention.

In accordance with the invention, the hydrocracking process of said hydrocarbon feedstock according to the invention is carried out at a temperature of between 200°C and 480°C, at a total pressure of between 1 MPa and 25 MPa, with a ratio volume of hydrogen per volume of hydrocarbon feed of between 80 and 5000 liters per liter and at an Hourly Volume Velocity (VVH) defined by the ratio of the volume flow of hydrocarbon feed to the volume of catalyst loaded into the reactor of between 0, 1 and 50 h-1.

Preferably, the hydrocracking process according to the invention operates in the presence of hydrogen, at a temperature between 250 and 480°C, preferably between 320 and 450°C, very preferably between 330 and 435°C. , under a pressure of between 2 and 25 MPa, preferably between 3 and 20 MPa, at a space speed of between 0.1 and 20 h-1, preferably 0.1 and 6 h-1, preferably between 0.2 and 3 h-1, and the quantity of hydrogen introduced is such that the volume ratio liter of hydrogen/liter of hydrocarbon is between 100 and 2000 L/L.

The process can be carried out in one step or two steps depending on the conversion level of the targeted feedstock, with or without recycling of the unconverted fraction. The catalyst according to the invention can be used in a non-limiting manner in one or both stages of the hydrocracking process, alone or in combination with another hydrocracking catalyst.

These operating conditions used in the processes according to the invention generally make it possible to achieve conversions per pass, in products having boiling points lower than 340°C, and better still lower than 370°C, greater than 15% by weight and even more preferably between 20 and 100% by weight.

The examples illustrate the invention without limiting its scope.

EXAMPLES

Example 1 – Preparation of a catalyst A according to the invention

The support of catalyst A is prepared by shaping by kneading-extrusion of 70% by weight of USY2 zeolite having a mesh parameter 24.37 Å, a molar SiO2/Al2O3 ratio of 11, a specific surface area measured by nitrogen physisorption according to the B.E.T method. of 864 m2/g, a microporous volume determined by nitrogen adsorption of 0.29 ml/g and a Brønsted acidity of 339 µmol/g in the presence of commercial Pural SB3 boehmite.

The extrudates obtained are dried at 80°C then calcined at 600°C in humid air (5% by weight of water per kg of dry air). The calcined support comprises, on a dry basis, 70% by weight of USY zeolite, and 30% by weight of alumina. After dry impregnation, the catalyst is dried at 120°C in air.

Catalyst A is prepared by dry impregnation of the support thus obtained using an aqueous solution containing the elements Ni, Mo. This solution is obtained by dissolving the following precursors in water: nickel nitrate, and heptamolybdate d 'ammonium. The quantity of precursors in solution is adjusted according to the concentrations targeted on the final catalyst.

The mass percentages in the catalyst are respectively: 10% by weight of molybdenum (in MoO3 form), 2.0% by weight of nickel (in NiO form) on a dry basis.

Example 2 – Preparation of a comparative catalyst B

The support for catalyst B is prepared by shaping by kneading-extrusion of 70% by weight of USY1 zeolite having a lattice parameter of 24.54 Å, a SiO2/Al2O3 molar ratio of 5.4, a specific surface area measured by physisorption of nitrogen according to the B.E.T. method. of 811 m2/g, a microporous volume determined by nitrogen adsorption of 0.28 ml/g and a Brønsted acidity of 600 µmol/g, in the presence of commercial boehmite (Pural SB3, Sasol). The extrudates obtained are dried at 80°C then calcined at 600°C in humid air (5% weight of water per kg of dry air). The calcined support comprises, on a dry basis, 70% by weight of USY zeolite, and 30% by weight of alumina.

Catalyst B is prepared by dry impregnation of the support thus obtained using an aqueous solution containing the elements Ni, Mo. This solution is obtained by dissolving the following precursors in water: nickel nitrate, and heptamolybdate d 'ammonium. The quantity of precursors in solution is adjusted according to the concentrations targeted on the final catalyst. After dry impregnation, the catalyst is dried at 120°C in air.

The mass percentages in the catalyst are respectively: 15.1% by weight of molybdenum (in MoO3 form), 3.3% by weight of nickel (in NiO form) on a dry basis.

Example 3 – Preparation of a catalyst C according to the invention

The support for catalyst C is prepared by shaping by kneading-extrusion of 35% by weight of USY zeolite (USY2) having a mesh parameter 24.37 Å, a SiO2/Al2O3 molar ratio of 11, a specific surface area measured by nitrogen physisorption according to the B.E.T. method. of 864 m2/g, a microporous volume determined by nitrogen adsorption of 0.29 ml/g and a Brønsted acidity of 339 µmol/g and 35% by weight of USY zeolite (USY1) having a lattice parameter of 24.54 Å, a molar SiO2/Al2O3 ratio of 5.4, a specific surface area measured by nitrogen physisorption according to the B.E.T. method. of 811 m2/g, a microporous volume determined by nitrogen adsorption of 0.28 ml/g and a Brønsted acidity of 600 µmol/g, in the presence of commercial boehmite (Pural SB3, Sasol).

The extrudates obtained are dried at 80°C then calcined at 600°C in humid air (5% weight of water per kg of dry air). The calcined support comprises, on a dry basis, 35% by weight of the first USY zeolite, and 35% by weight of the second USY zeolite and 30% by weight of alumina, i.e. a USY1/USY2 weight ratio of 1.

Catalyst C is prepared by dry impregnation of the support thus obtained using an aqueous solution containing the elements Ni, Mo. This solution is obtained by dissolving the following precursors in water: nickel nitrate, and heptamolybdate d 'ammonium. The quantity of precursors in solution is adjusted according to the concentrations targeted on the final catalyst. After dry impregnation, the catalyst is dried at 120°C in air.

The mass percentages in the catalyst are respectively: 15.1% by weight of molybdenum (in MoO3 form), 3.3% by weight of nickel (in NiO form) on a dry basis.

Example 4 – Preparation of a catalyst D according to the invention

The support for catalyst D is prepared by shaping by kneading-extrusion of 30% by weight of USY zeolite (USY2) having a mesh parameter 24.37 Å, a SiO2/Al2O3 molar ratio of 11, a specific surface area measured by nitrogen physisorption according to the B.E.T. method. of 864 m2/g, a microporous volume determined by nitrogen adsorption of 0.29 ml/g and a Brønsted acidity of 339 µmol/g and 30% by weight of USY zeolite (USY1) having a lattice parameter of 24.54 Å, a molar SiO2/Al2O3 ratio of 5.4, a specific surface area measured by nitrogen physisorption according to the B.E.T. method. of 811 m2/g, a microporous volume determined by nitrogen adsorption of 0.28 ml/g and a Brønsted acidity of 600 µmol/g, and 10% by weight of commercial Beta zeolite (CP814e, Zeolyst) having a ratio SiO2/Al2O3 molar of 25, a specific surface area measured by nitrogen physisorption according to the B.E.T. method. of 670 m2/g, in the presence of commercial boehmite PuralSB3.

The extrudates obtained are dried at 80°C then calcined at 600°C in humid air (5% weight of water per kg of dry air). The calcined support comprises, on a dry basis, 30% by weight of USY2, 30% by weight of USY1, 10% by weight of Beta zeolite and 30% by weight of alumina, i.e. a USY1/USY2 weight ratio of 1.

Catalyst C is prepared by dry impregnation of the support thus obtained using an aqueous solution containing the elements Ni, Mo. This solution is obtained by dissolving the following precursors in water: nickel nitrate, and heptamolybdate d 'ammonium. The quantity of precursors in solution is adjusted according to the concentrations targeted on the final catalyst. After dry impregnation, the catalyst is dried at 120°C in air.

The mass percentages in the catalyst are respectively: 15.1% by weight of molybdenum (in MoO3 form), 3.3% by weight of nickel (in NiO form) on a dry basis.

Example 5

The performances of the catalysts described above are evaluated by hydrocracking a feed comprising a vacuum distillate and gas oil fraction in one step using a pilot isothermal test unit in downflow configuration.

This test load undergoes hydrotreatment (HDT). After this hydrotreatment step, the test load has a density at 15°C of 0.8755 g/mL, a residual nitrogen content of 23 ppm wt and a residual sulfur content of 16 ppm wt. The initial point of the simulated distillation for this test load after hydrotreatment is 163.3°C and the end point is 578.7°C. The 50% wt point of the simulated distillation is at 391.7°C. In order to simulate the partial pressure of hydrogen sulfide and ammonia generated by the HDT stage of the process, the test charge is added respectively with DMDS and aniline so as to obtain 8820 ppm wt of sulfur and 1900 ppm weight of nitrogen in the final additive charge.

Each catalyst is evaluated separately and is sulphurized prior to the hydrocracking test under SRGO load or straight run gas oil, i.e. gas oil from the direct distillation of petroleum with an additive of 4% by weight of dimethyl sulphide (DMDS) and 2% by weight aniline. Sulfurization is carried out at VVH of 2 h-1 (VVH = Hourly Volume Velocity), an H2/charge volume ratio of 1000 NL/L, a total pressure of 140 bar (i.e. 14.0 MPa) and a bearing temperature of 350°C for 6 hours.

After sulfurization, the operating conditions are adjusted to those used for the hydrocracking test: VVH of 1.5 h-1, an H2/feed volume ratio of 1000 NL/L, a total pressure of 140 bar (i.e. 14.0 MPa). The temperature of the reactors is adjusted so as to target a net conversion of the 216 °C+ fraction of 65% by weight after 150 hours under load.

Net conversion is defined as the cut yield (or fraction) of boiling point below 216°C minus the cut yield of boiling point below 216°C present in the test charge.

The characteristics of the USY1 and USY2 zeolites are summarized in Table 1.

The performances of the catalysts are compared to that of catalyst B taken as a reference and reported in Table 2. The relative activity in degrees Celsius (°C) is obtained by difference in temperatures between the catalyst to be evaluated and that obtained for catalyst B benchmark to achieve a net conversion of 65%. Likewise, the relative yield in the 68-216°C cut is taken as the difference between the yields obtained at 65% net conversion weight of the 216°C+ cut. A positive value induces greater activity or output. A negative value induces a reduction in activity or output.

USY zeolite SiO ₂ /Al ₂ O ₃ (molar) Mesh parameter (Å) S _BET
(m²/g) V _micro (ml/g) Acidity of the
(µmole/g) USY2 11 24.37 864 0.29 339 USY1 5.4 24.54 811 0.28 600

Table 1: Characteristics of USY1 and USY2 zeolites

Catalysts USY zeolite USY/Beta mass ratio USY1 (% weight relative to the support) USY2 (% weight relative to the support) Beta (%wt relative to support) Relative activity (°C) Relative yield (%wt) A (comparative) USY2 - 70 0 0 -1.5 4.5 B (comparative) USY1 - 0 70 0 0 0 C (according to the invention) USY1, USY2 - 35 35 0 -0.5 4.5 D (according to the invention) USY1, USY2, Beta 6 30 30 10 3.5 4.5

Table 2. Characteristics and performance positioning of catalysts A to D.

The results reported in Table 2 show that catalyst A using specific USY2 zeolite makes it possible to increase the naphtha cutting yield compared to reference catalyst B (increase in relative yield of 4.5% by weight), but this is at least to the detriment of less converting activity (reduction in relative activity of 1.5°C).

On the other hand, the combination of zeolites USY1 and USY2 for catalyst C according to the invention allows an increase in the converter activity compared to catalyst A, reaching that of catalyst B, while maintaining a high yield in naphtha cut, equivalent to that obtained with catalyst A. Thus catalyst C has a relative converting activity of -0.5°C and a relative yield of +4.5% by weight compared to the reference catalyst B.

We also note that the addition of the Beta zeolite to the USY1 and USY2 zeolites according to the invention for catalyst D makes it possible to further increase the relative converting activity at +3.5 °C while maintaining a high relative cutting efficiency. naphtha of +4.5% by weight compared to catalyst B.

Claims (11)

Hydrocracking catalyst comprising at least one hydro-dehydrogenating element chosen from the group formed by the elements of group VIB and non-noble group VIII taken alone or as a mixture of the periodic table, and a support comprising at least one porous mineral matrix, a first zeolite Y having an initial crystal parameter a0 of the unit cell greater than 24.42 Å and a second zeolite Y having an initial crystal parameter a0 of the unit cell strictly less than 24.40 Å, a BET specific surface area of between 700 and 1000 m2/g, a microporous volume determined by nitrogen adsorption greater than 0.28 ml/g and a Brønsted acidity greater than 300 micromole/g. Catalyst according to claim 1 in which the group VIII elements are chosen from iron, cobalt, nickel, taken alone or in a mixture and preferably from nickel and cobalt, the group VIII element content being between 0.5 and 8% by weight of oxide, preferably between 0.5 and 6% by weight of oxide and very preferably between 1.0 and 4% by weight of oxide, relative to the total weight of said catalyst. Catalyst according to one of claims 1 or 2 in which the elements of group VIB are chosen from tungsten and molybdenum, taken alone or as a mixture, the element content of group VIB being between 1 and 30% by weight of oxide, preferably between 2 and 25% by weight of oxide, very preferably between 5 and 20% by weight of oxide, and even more preferably between 5 and 16% by weight of oxide, relative to to the total weight of said catalyst. Catalyst according to one of claims 1 to 3 in which the mesh parameter of said first zeolite is between 24.42 Å and 24.70 Å, preferably greater than 24.45 Å and less than 24.70 Å, of preferably greater than 24.50 Å and less than 24.70 Å, preferably between 24.52 Å and 24.70 Å and preferably between 24.52 Å and 24.65 Å, preferably between 24, 52 Å and 24.60 Å and very preferably between 24.52 Å and 24.58 Å. Catalyst according to one of claims 1 to 4 in which said second zeolite Y has a Brønsted acidity of between 320 and 500 micromole/g and preferably between 325 and 425 micromole/g. Catalyst according to one of claims 1 to 5 in which the initial crystal parameter a0 of the unit cell of the second zeolite Y is between 24.30 Å and 24.39 Å, preferably between 24.32 Å and 24, 39 Å, preferably between 24.32 Å and 24.38 Å, and very preferably between 24.34 Å and 24.38 Å. Catalyst according to one of claims 1 to 6 in which the support also comprises a Beta zeolite, the weight ratio of said Y zeolite to said Beta zeolite in the catalyst is between 1 and 40. Catalyst according to one of claims 1 to 7 in which the catalyst has a total weight content of zeolite Y of between 7 and 78% by weight relative to the total weight of said catalyst. Catalyst according to one of claims 1 to 8 in which in the case where a Beta zeolite is present in the formulation of the catalyst, said catalyst has a Beta zeolite content of between 2 and 39% by weight relative to the total weight of said catalyst. Catalyst according to one of claims 1 to 9 in which said catalyst has a content of at least one porous mineral matrix of between 4 and 81% by weight relative to the total weight of said catalyst. Process for hydrocracking at least one hydrocarbon feedstock of which at least 50% by weight of the compounds have an initial boiling point greater than 300 °C and a final boiling point less than 650 °C, at a temperature between 200 °C and 480 °C, at a total pressure between 1 MPa and 25 MPa, with a ratio of volume of hydrogen per volume of hydrocarbon feed of between 80 and 5000 liters per liter and at an Hourly Volume Velocity (VVH) defined by the ratio of the volume flow of hydrocarbon feed to the volume of catalyst loaded into the reactor of between 0.1 and 50 h-1, in the presence of the catalyst according to one of claims 1 to 10.