FR2775202A1 - Zeolite based catalyst for hydrocracking of hydrocarbonaceous feeds - Google Patents

Abstract

The catalyst comprises a zeolite-based matrix selected from NU-85, NU-86 or NU-87, at least a metal from group VIB and group VIII, at least an element from boron, silicon, phosphorous, optionally an element from group VIIA and optionally an element from group VIIB.

Description

The present invention relates to a charge hydrocracking catalyst

  hydrocarbons, said catalyst comprising at least one metal chosen from the group formed by the metals of group VIB and group VIII (group 6 and / or groups 8, 9 and 10 according to the new notation of the periodic classification of elements: Handbook of Chemistry and Physics, 76th edition, 1995-1996), associated with a support comprising an amorphous or poorly crystallized matrix of the type

  oxide and a zeolite chosen from the group formed by the zeolites NU86 and NU-

  87. The catalyst matrix contains, as promoter, at least one element chosen from boron and silicon, and optionally phosphorus, and optionally at least one element from group VIIA (group 17 of halogens) and in particular the

  fluorine, and optionally at least one element from group VIIB.

  Hydrocracking of heavy petroleum fractions is a very important refining process which makes it possible to produce, from excess heavy and little recoverable charges, the lighter fractions such as gasolines, jet fuels and light gas oils that the refiner seeks to adapt its production to the structure of demand. Certain hydrocracking processes also make it possible to obtain a highly purified residue which can constitute excellent bases for oils. Compared with catalytic cracking, the advantage of catalytic hydrocracking is to provide middle distillates, jet fuels and diesel oils, of very good quality. The gasoline produced has a much lower octane number than that from

catalytic cracking.

  The catalysts used in hydrocracking are generally of the bifunctional type combining an acid function with a hydrogenating function. The acid function is provided by supports of large surfaces (150 to 800 m2.g-1 generally) having a surface acidity, such as halogenated aluminas (chlorinated or

  fluorinated in particular), amorphous silica-aluminas and zeolites.

  The hydrogenating function is provided either by one or more metals from group VIII of the periodic table of elements, such as iron, cobalt, nickel, ruthenium, rhodium, palladium, osmium, iridium and platinum, preferably cobalt, nickel and iron, or by a combination of at least one metal from group VI of the periodic table such as molybdenum, tungsten, chromium and at least one metal from group

VIII.

  The balance between the two acid and hydrogenating functions is the fundamental parameter which governs the activity and the selectivity of the catalyst. A weak acid function and a strong hydrogenating function give catalysts that are not very active, working at a generally high temperature (greater than or equal to 390 ° C.), and at low spatial feed speed (the VVH expressed in volume of charge to be treated per unit volume of catalyst and per hour is generally less than or equal to 2) but with very good selectivity for middle distillates. Conversely, a strong acid function and a weak hydrogenating function give active catalysts but having poorer selectivities for middle distillates. The search for a suitable catalyst will therefore focus on a judicious choice of

  each of the functions to adjust the activity / selectivity couple of the catalyst.

  Thus, it is one of the great advantages of hydrocracking to present great flexibility at various levels: flexibility at the level of the catalysts used, which brings flexibility of the feeds to be treated and at the level of the products obtained. A parameter

  easy to control is the acidity of the catalyst support.

  The conventional catalysts for catalytic hydrocracking are, for the most part, made up of weakly acidic supports, such as amorphous silica-aluminas for example. These systems are more particularly used to produce very good quality middle distillates, and again, when their acidity is very low,

oil bases.

  In weakly acidic supports, we find the family of amorphous silica-aluminas.

  Many catalysts in the hydrocracking market are based on silica-

  alumina associated either with a group VIII metal or, preferably when the heteroatomic content of the charge to be treated exceeds 0.5% by weight, with a combination of sulfides of the metals of groups VIB and VIII. These systems have very good selectivity for middle distillates, and the products formed are of good quality. These catalysts, for the least acidic of them, can also produce lubricating bases. The disadvantage of all these catalytic systems

  amorphous support base is, as has been said, their low activity.

  Catalysts comprising, for example, zeolite Y of structural type FAU, or catalysts comprising, for example, a zeolite of beta type, exhibit a catalytic activity greater than that of amorphous silica-aluminas, but

  have higher selectivities for light products.

  The research carried out by the applicant on numerous zeolites and microporous crystalline solids led him to discover that, surprisingly, a catalyst containing a zeolite chosen from the group formed by the zeolites NU-86 and NU-87, at least one metal chosen from the group formed by the metals of group VIB and group VIII of the periodic table, at least one element chosen from boron and silicon, optionally phosphorus, optionally at least one element from group VIIA, optionally at minus one element of the VIIB group, enables activities to be obtained, that is to say a higher level of conversion,

  than the catalysts known in the prior art.

  The hydrogenating function is chosen from metals from group VIII such as iron, cobalt, nickel, ruthenium, rhodium, palladium, osmium, iridium and platinum and from metals from group VIB such as molybdenum, tungsten and chromium. The possible element of group VIIA is chosen from fluorine, chlorine, bromine and iodine, preferably fluorine and chlorine. The element of group VIIB is chosen from the

manganese and rhenium.

  More specifically, the subject of the invention is a composition comprising at least one matrix and one zeolite chosen from the group formed by zeolites

NU-86 and NU-87.

  The NU-86 zeolite, in hydrogen form or partially in hydrogen form, designated by H-NU-86 and obtained by calcination and / or ion exchange of the crude synthetic NU-86 zeolite, used in the process according to the invention thus

  that the mode of synthesis of said crude synthesis, are described in patent EP-

0463768 A2.

  The structural type of this zeolite has not yet been officially assigned by the synthesis committee of the IZA (International Zeolite Association). However, following the work published at the 9th International Congress on Zeolites by JL Casci, PA Box and MD Shannon ("Proceedings of the 9th International Zeolite Conference, Montreal 1992, Eds R. Von Balimoos et al., 1993 by Butterworth) it appears that: - the NU-86 zeolite has a three-dimensional microporous system; - this three-dimensional microporous system consists of straight channels whose pore opening is bounded by 11 T atoms (tetrahedral atoms: Si, AI, Ga, Fe ..) , straight channels alternately delimited by openings with 10 and 12 T atoms and sinusoidal channels also delimited alternately by openings with 10 and 12 T atoms. The term pore opening means 10, 11 or 12 tetrahedral atoms. (T)

  pores consisting of 10, 11 or 12 sides.

  The NU-86 zeolite used in the composition according to the invention is at least in part, preferably practically totally, in acid form, that is to say in hydrogen form (H +). The Na / T atomic ratio is generally less than 90% and

  preferably less than 50% and even more preferably less than 10%.

  As regards the NU-87 zeolite of the NES structural type also used in the present invention, it is described in patent EP-A1-377291 as well as in the document "Atlas of Zeolite Structure Types", by WM Meier, DH Oison and

  Ch. Baerlocher, Fourth revised edition 1996, Elsevier.

  The zeolites NU-86 and NU-87 will preferably be used at least partly in acid form (and preferably entirely in H form) or partially exchanged

  with metal cations, for example cations of alkaline earth metals.

  The NU-86 and NU-87 zeolites which form part of the composition according to the invention are

  used with the silicon and aluminum contents obtained in the synthesis.

  The catalyst of the present invention therefore also contains at least one porous amorphous or poorly crystallized oxide-type mineral matrix. Mention may be made, by way of nonlimiting example, of aluminas, silicas, silica-aluminas. We can also choose aluminates. It is preferred to use matrices containing alumina, in all of these forms known to those skilled in the art, and so

  even more preferred aluminas, for example gamma alumina.

  The catalyst is also characterized in that it contains at least one element chosen from boron and silicon and optionally phosphorus, optionally at least one element from group VIIA, preferably fluorine, and also optionally at least one element from VIIB group. The catalyst also contains a hydrogenating function. The hydrogenating function as defined above, that is to say at least one metal chosen from the group formed by the metals of the group

VIB and group VIII.

  The catalyst of the present invention generally contains in% by weight relative to the total mass of the catalyst at least one metal chosen from the following groups and with the following contents: - 0.1 to 60%, preferably from 0.1 to 50 % and even more preferably from 0.1 to% of at least one metal chosen from the group formed by the metals of group VIB and of group VIII, - the catalyst also contains at least one porous mineral matrix which is amorphous or poorly crystallized oxide type, whose weight content relative to the whole of the catalyst varies from 0.1 to 99%, preferably from 1 to 99%, - the catalyst additionally contains from 0.1 to 90%, preferably from 0.1 to 80% and even more preferably from 0.1 to 70% of a zeolite chosen from the group formed by the NU-86 and NU-87 zeolites, the said catalyst being characterized in that it contains from - 0.1 to 20%, preferably from 0.1 to 15% and even more preferably from 0.1 to 10% of at least one promoter element chosen from boron and silicon, and optionally, - 0 to 20%, preferably from 0 to 15% and even more preferably from 0.1 to% of phosphorus, and optionally still, 0 to 20%, preferably from 0.1 to 15% and even more preferably from 0.1 to

  10% of at least one element chosen from group VIIA, preferably fluorine.

  and optionally still, - 0 to 20%, preferably from 0.1 to 15% and even more preferably from 0.1 to

  % of at least one element chosen from the VIIB group.

  The metals of group VIB, group VIII and group VIIB of the catalyst of the present invention may be present in whole or in part in the form

  metallic and / or oxide and / or sulfide.

  The catalysts according to the invention can be prepared by any suitable method. Preferably, at least one element chosen from silicon and boron is introduced onto a support already containing a zeolite chosen from the group

  formed by zeolites NU-86 and NU-87, at least one matrix, as defined above

  before, and the metal or metals of groups VIB and / or at least one element of group VIII and optionally phosphorus. Preferably, the support is impregnated with at

  at least one aqueous solution of at least one element chosen from boron and silicon.

  When the catalyst contains it, the silicon introduced onto the support according to the invention is mainly located on the matrix of the support and can be characterized by techniques such as the Castaing microprobe (distribution profile of the various elements), electron microscopy by transmission coupled with an X-analysis of the components of the catalysts, or even by the establishment of a mapping of

  distribution of the elements present in the catalyst by electronic microprobe.

  These local analyzes will provide the location of the various elements, in particular the location of the amorphous silica on the support matrix due to the introduction of the silicon according to the invention. The location of the silicon of the framework of the zeolite contained in the support is also revealed. In addition, a quantitative estimate

  local contents of silicon and other elements may be carried out.

  On the other hand, the NMR of the solid of 29Si rotating at the magic angle is a technique which makes it possible to detect the presence of amorphous silica introduced into the catalyst.

  according to the procedure described in the present invention.

  More particularly, the process for the preparation of the catalyst of the present invention comprises the following steps: a) drying and weighing a solid hereinafter called the precursor, containing at least the following compounds: at least one matrix, one zeolite chosen from the group formed by zeolites NU-86 and NU-87, at least one element chosen from the group formed by the metals of group VIB and group VIII, the whole being preferably shaped, b) the impregnated solid precursor defined in step a), with at least one aqueous solution containing at least one element chosen from boron and silicon, optionally phosphorus and optionally at least one element from group VIIA, preferably fluorine (F), and optionally at least one element from group VIIB, c) the wet solid is allowed to stand under a humid atmosphere at a temperature between 10 and 80 ° C., d) the wet solid obtained in step b) is dried at e temperature between 60 and 150 C, e) the solid obtained in step c) is calcined at a temperature between 150 and

800 C.

  Step b) above can be carried out according to the conventional methods of a person skilled in the art. In an embodiment of the invention in which the catalyst contains boron, a preferred method consists in preparing an aqueous solution of at least one boron salt such as ammonium biborate or ammonium pentaborate in an alkaline medium and in the presence of hydrogen peroxide and to carry out a so-called dry impregnation, in which the pore volume of the precursor is filled with the solution containing boron. If we deposit If we will use a solution of a compound of

silicon type silicon.

  In another embodiment of the invention in which the catalyst contains boron and silicon, the deposition of boron and silicon can be carried out simultaneously using a solution containing a boron salt and a type silicon compound silicone. Thus, for example in the case where for example the precursor is a nickel-molybdenum type catalyst supported on alumina, it is possible to impregnate this precursor with aqueous solution of ammonium biborate and of silicone Rhodorsil El P from the Rhône Poulenc company to carry out a drying for example at 80 ° C., then to impregnate with an ammonium fluoride solution, to carry out a drying for example at 80 ° C., and to carry out a calcination for example and preferably under air in a crossed bed, for example at

500 C for 4 hours.

  The element chosen from boron and silicon, optionally phosphorus, optionally at least one element chosen from group VIIA of halide ions, preferably F, optionally at least one element chosen from group VIIB can be introduced into the catalyst to various levels of the preparation and in various ways, for example by one or more impregnation operations with excess solution on the calcined precursor. The impregnation of the matrix is preferably carried out by the so-called "dry" impregnation method. known to those skilled in the art. Impregnation can be carried out in a single step with a solution containing all of the

  constituent elements of the final catalyst.

  Thus, for example, it is possible to impregnate the precursor with an aqueous solution of ammonium biborate or of silicone Rhodorsil El P from the company Rhône Poulenc to carry out a drying for example at 80 ° C., then to impregnate with a ammonium fluoride solution, to carry out a drying for example at 80 ° C., and to carry out a calcination for example and preferably in air in a crossed bed, by

example at 500 C for 4 hours.

  Other impregnation sequences can be used to obtain the

  catalyst of the present invention.

  It is for example possible to impregnate the precursor with a solution containing phosphorus, to dry, to calcine and then to impregnate the solid obtained with the solution containing boron, to dry, to calcine. It is also possible to impregnate the precursor with a solution containing phosphorus, to dry, to calcine and then to impregnate the solid obtained with the solution containing silicon, to dry, and to

  proceed to a final calcination.

  The possible impregnation of at least one element of group VIIB, for example molybdenum, can be facilitated by adding phosphoric acid to the ammonium paramolybdate solutions, which also makes it possible to introduce phosphorus so as to promote l catalytic activity. Other phosphorus compounds can be

  used as is well known to those skilled in the art.

  In the case where the metals are introduced in several impregnations of the corresponding precursor salts, an intermediate drying step of the catalyst is generally carried out at a temperature generally between 60 and

250 C.

  In the case where the elements are introduced in several impregnations of the corresponding precursor salts, an intermediate calcination step of the catalyst

  should be carried out at a temperature between 250 and 600 C.

  The precursor defined in step a) above which forms part of the composition of the catalyst according to the invention contains at least the following compounds, at least one matrix, a zeolite chosen from the group formed by zeolites NU-86 and NU-87, at least one element from group VIB, and optionally at least one element from group VIII, optionally boron or silicon, optionally phosphorus, the whole being preferably formed This precursor can be prepared by any method well known to those skilled in the art. Advantageously, it is obtained by mixing the matrix and the zeolites and then shaping. The hydrogenating element is introduced during mixing, or even after shaping (preferred). The shaping is followed by a calcination, the hydrogenating element is introduced before or after this calcination. The preparation is

  in all cases ends with calcination at a temperature of 250 to 600 C.

  One of the preferred methods in the present invention consists in kneading at least one zeolite chosen from the group formed by the zeolites NU86 and NU-87, in a wet alumina gel for a few tens of minutes, then in passing the paste thus obtained. through a die to form extrudates of included diameter

between 0.4 and 4 mm.

  The hydrogenating function can be introduced in part only (case, for example, of associations of metal oxides of groups VIB and VIII) or in whole at the time of the kneading of the zeolite, that is to say at least one zeolite chosen from the whole formed by the NU-86 and NU-87 zeolites, with the oxide gel chosen as matrix. It can be introduced by one or more ion exchange operations on the calcined support consisting of at least one zeolite chosen from the group formed by the zeolites NU-86 and NU-87, dispersed in the chosen matrix, at the using solutions containing the precursor salts of the metals chosen when these belong to group VIII. It can be introduced by one or more operations of impregnating the shaped and calcined support, with a solution of the precursors of the oxides of the metals of groups VIII (in particular cobalt and nickel) when the precursors of the oxides of the metals of group VIB (especially molybdenum or

  tungsten) were previously introduced at the time of mixing the support.

  Finally, it can be introduced by one or more operations for impregnating the calcined support constituted by at least one zeolite chosen from the group formed by the zeolites NU-86 and NU-87 and the matrix, by solutions containing the precursors of the metal oxides of groups VI and / or VIII, the precursors of group VIII metal oxides being preferably introduced after those of group

  VI or at the same time as these.

  The sources of elements of group VIB which can be used are well known to those skilled in the art. For example, among the sources of molybdenum and tungsten, it is possible to use oxides and hydroxides, molybdic and tungstic acids and their salts, in particular ammonium salts such as ammonium molybdate, ammonium heptamolybdate, ammonium tungstate, 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.

  The catalyst of the present invention may contain a group VIII element such as

  as iron, cobalt, nickel, ruthenium, rhodium, palladium, osmium, iridium or platinum.

  Among the metals of group VIII, the non-noble metals iron, cobalt and nickel are preferred. Advantageously, the following combinations of metals are used: nickel-molybdenum, cobalt-molybdenum, iron-molybdenum, iron-tungsten,

  nickel-tungsten, cobalt-tungsten, the preferred combinations are: nickel-

  molybdenum, cobalt-molybdenum. It is also possible to use associations of

  three metals, for example nickel-cobalt-molybdenum.

  The sources of group VIII elements which can be used are well known to those skilled in the art. For example, for non-noble metals, the nitrates, the sulfates, the phosphates, the halides, for example chlorides, bromides and fluorides, the carboxylates, for example acetates and carbonates, will be used. For noble metals, halides will be used, for example the chlorides, the nitrates, the acids such as chloroplatinic acid, the oxychlorides such as the ammoniacal ruthenium oxychloride. Many sources of silicon can be used. Thus, it is possible to 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 impregnating ethyl silicate in solution in a water / alcohol mixture. The silicon can be added for example by impregnation of a silicon compound of the type

  silicone suspended in water.

  The boron source 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 of the pyridine and quinoline family and compounds of the pyrrole family. Boron can be introduced for example by a boric acid solution

in a water / alcohol mixture.

  The preferred phosphorus source is orthophosphoric acid H3PO4, but its salts and esters such as ammonium phosphates are also suitable. The 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 family of pyridine and quinolines and family compounds

pyrrole.

  The sources of elements of the VIIA group which can be used are well known to those skilled in the art. For example, the 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 hydrofluoric acid. It is also possible to use hydrolysable compounds which can release fluoride anions in water, such as ammonium fluorosilicate (NH4) 2SiF6, silicon tetrafluoride SiF4 or sodium Na2SiF6. Fluorine can be introduced for example by impregnating an aqueous acid solution

  hydrofluoric acid or ammonium fluoride.

  The sources of elements of the VIIB group which can be used are well known to those skilled in the art. Ammonium salts, nitrates and

chlorides.

  The catalysts thus obtained, in oxide form, can optionally be

  brought at least in part in metallic or sulphide form.

  The catalysts obtained by the present invention are shaped in the form of grains of different shape and dimensions. They are generally used in the form of cylindrical or multi-lobed extrudates such as two-lobed, three-lobed, multi-lobed in straight or twisted shape, but can optionally be manufactured and used in the form of crushed powder, tablets, rings, balls , wheels. They have a specific surface area measured by nitrogen adsorption according to the BET method (Brunauer, Emmett, Teller, J. Am. Chem. Soc., Vol. 60, 309-316 (1938)) of between 50 and 600 m2 / g , a pore volume measured by mercury porosimetry of between 0.2 and 1.5 cm3 / g and a pore size distribution that can

  be monomodal, bimodal or polymodal.

  The catalysts obtained by the present invention are used for hydrocracking hydrocarbon feedstocks such as petroleum fractions. The fillers used in the process are gasolines, kerosene, gas oils, vacuum gas oils, atmospheric residues, vacuum residues, atmospheric distillates, vacuum distillates, heavy fuels, oils, waxes and paraffins, used oils, deasphalted residues or crudes, fillers from thermal or catalytic conversion processes and their mixtures. They contain heteroatoms such as sulfur, oxygen and nitrogen and

possibly metals.

  The catalysts thus obtained are advantageously used for hydrocracking in particular heavy hydrocarbon cuts of the distillate type under vacuum, deasphalted or hydrotreated residues or the like. Heavy cuts are preferably made up of at least 80% by volume of compounds whose boiling points are at least 350 C and preferably between 350 and 580 C (i.e.

  corresponding to compounds containing at least 15 to 20 carbon atoms).

  They generally contain heteroatoms such as sulfur and nitrogen. The nitrogen content is usually between 1 and 5000 ppm by weight and the sulfur content

between 0.01 and 5% by weight.

  The hydrocracking conditions such as temperature, pressure, hydrogen recycling rate, hourly volume speed, may be very variable depending on the nature of the feed, the quality of the desired products and the facilities available to the refiner. The temperature is generally greater than 200 C and often between 250 C and 480 C. The pressure is greater than 0.1 MPa and often greater than 1 MPa. The hydrogen recycling rate is at least 50 and often between 80 and 5000 normal liters of hydrogen per liter of charge. The hourly space velocity is generally between 0.1 and 20

  volume of charge per volume of catalyst and per hour.

  The catalysts of the present invention are preferably subjected to a sulphurization treatment making it possible to transform, at least in part, the metallic species into sulphide before they are brought into contact with the charge to be treated. This activation treatment by sulfurization is well known to those skilled in the art and can

  be performed by any method already described in the literature.

  A conventional sulfurization method well known to a person skilled in the art consists in heating in the presence of hydrogen sulphide at a temperature of between 150 and 800 ° C., preferably between 250 and 600 ° C., generally in an area

reaction with crossed bed.

  The catalyst of the present invention can be advantageously used for the hydrocracking of sections of the distillate type under vacuum highly charged with sulfur and nitrogen. In a first embodiment or partial hydrocracking also called mild hydrocracking, the conversion level is less than 55%. The catalyst according to the invention is then used at a temperature generally greater than or equal to 230 C and preferably at 300 C, generally at most 480 C, and often between 350 C and 450 C. The pressure is generally greater than 2MPa and preferably 3Mpa and at most 12 Mpa, preferably at most 10MPa. The quantity of hydrogen is at least 100 normal liters of hydrogen per liter of charge and often between 200 and 3000 normal liters of hydrogen per liter of charge. The hourly space velocity is generally between 0.1 and 10h-1. Under these conditions, the catalysts of the present invention exhibit better activity in conversion, in hydrodesulfurization and in hydrodenitrogenation than the catalysts of

prior art.

  In a second embodiment, the catalyst of the present invention can be used for partial hydrocracking, advantageously under conditions of moderate hydrogen pressure, of sections, for example of the vacuum distillate type highly charged with sulfur and nitrogen which have been previously hydrotreated. In this hydrocracking mode the conversion level is less than 55%. In this case the petroleum cut conversion process takes place in two stages, the

  catalysts according to the invention being used in the second step.

  The catalyst of the first stage can be any hydrotreating catalyst contained in the state of the art. This hydrotreatment catalyst advantageously comprises a matrix preferably based on alumina and at least one metal having a hydrogenating function. The hydrotreatment function is provided by at least one metal or metal compound, alone or in combination, chosen from metals from group VIII and group VIB, such as nickel, cobalt, molybdenum and tungsten in particular. In addition, this catalyst may optionally contain

  phosphorus and possibly boron.

  The first stage generally takes place at a temperature of 350-460 C, preferably 360-4500C, a total pressure of at least 2MPa, and preferably 3 MPa, an hourly volume speed of 0.1-5h-1 and preferably 0.2-2h-1 and with a quantity of hydrogen of at least 100NI / NI of charge, and preferably 260-3000NI / NI

dump.

  For the conversion step with the catalyst according to the invention (or second step), the temperatures are generally greater than or equal to 230 C and often between 300 C and 480 C and preferably between 330 and 450 C. The pressure is generally at least 2 MPa and preferably 3Mpa at most 12 Mpa, preferably at most 10 MPa. The quantity of hydrogen is at least 1001 / I of charge and often between 200 and 30001/1 of hydrogen per liter of charge. The hourly space velocity is generally between 0.15 and 10h-1. Under these conditions, the catalysts of the present invention exhibit better activity in conversion, in hydrodesulfurization, in hydrodenitrogenation and better selectivity in middle distillates than the catalysts of the prior art. The service life of

  catalysts is also improved in the moderate pressure range.

  In another embodiment, the catalyst of the present invention can be used for hydrocracking under conditions of high hydrogen pressure of at least 5 MPa. The treated sections are, for example, of the vacuum distillates type highly charged with sulfur and nitrogen which have been hydrotreated beforehand. In this hydrocracking mode the conversion level is greater than 55%. In this case, the petroleum cut conversion process takes place in two stages, the

  catalyst according to the invention being used in the second step.

  The catalyst of the first stage can be any hydrotreating catalyst contained in the state of the art. This hydrotreatment catalyst advantageously comprises a matrix preferably based on alumina and at least one metal having a hydrogenating function. The hydrotreatment function is provided by at least one metal or metal compound, alone or in combination, chosen from metals from group VIII and group VIB, such as nickel, cobalt, molybdenum and tungsten in particular. In addition, this catalyst may optionally contain

  phosphorus and possibly boron.

  The first step generally takes place at a temperature of 350-460 C, preferably 360-450 C, a pressure greater than 3MPa, an hourly volume speed of 0.1-5h-1 and preferably 0.2-2h-1 and with a quantity hydrogen from

  minus 1 OONI / NI charge, and preferably 260-3000NI / NI charge.

  For the conversion step with the catalyst according to the invention (or second step), the temperatures are generally greater than or equal to 230 C and often between 300 C and 480 C and preferably between 300 and 440 C. The pressure is generally greater than 5 MPa and preferably greater than 7 MPa. The quantity of hydrogen is at least 1001 / I of charge and often between 200 and 30001 / I of hydrogen per liter of charge. The hourly space velocity is included in

generally between 0.15 and 10h-1.

  Under these conditions, the catalysts of the present invention exhibit better conversion activity and better selectivity for middle distillates than the catalysts of the prior art, even for zeolite contents.

  considerably lower than those of the catalysts of the prior art.

  The following examples illustrate the present invention without, however, limiting its

scope.

  EXAMPLE 1 Preparation of a Support Containing an NU-86 Zeolite A hydrocracking catalyst support containing a NU-86 zeolite was manufactured in large quantities so as to be able to prepare different catalysts based on the same support. The raw material used is a NU-86 zeolite, which is prepared according to example 2 of patent EP 0 463 768 A2 and has an Si / AI ratio.

  global atomic equal to 10.2 and an Na / AI atomic ratio equal to 0.25.

  This crude NU-86 zeolite is first subjected to a so-called dry calcination at 550 ° C. under a flow of dry air for 9 hours. Then the solid obtained is subjected to four ionic exchanges in a NH4NO3 10ON solution, at approximately 100 ° C. for 4 hours for each exchange. The solid thus obtained is referenced NH4-NU-86/1 and has an Si / Al ratio = 10.4 and an Na / Al ratio = 0.013. His others

  physicochemical characteristics are grouped in table 1.

Table 1

  Sample X-ray diffraction Adsorption SBET V crystallinity (P / Po = 0.19) (%) (m2 / g) ml N2 liquid / g

NH4-NU-86/1 100 423 0.162

  The crystallites of the NU-86 zeolite are in the form of crystals ranging in size from 0.4 μm to 2 μm. Then, 19.5 g of the NH4-NU-86/2 zeolite are mixed with 80.5 g of a matrix composed of ultrafine tabular boehmite or alumina gel sold under the name SB3 by the company Condéa Chemie Gmbh. This powder mixture was then mixed with an aqueous solution containing 66% by weight nitric acid (7% by weight of acid per gram of dry gel) and then kneaded for 15 minutes. The kneaded dough is then extruded through a 1.2 mm diameter die. The extrudates are

  then calcined at 500 C for 2 hours in air.

  Example 5 Preparation of Hydrocracking Catalysts Containing an NU-86 Zeolite The support extrudates containing an NU-86 zeolite of Example 1 are dry impregnated with an aqueous solution of ammonium heptamolybdate, dried overnight. at 120 C in air and finally calcined in air at 550 C. Weight contents

  in NU86Mo catalyst oxides obtained are shown in Table 2.

  The NU86Mo catalyst was then impregnated with an aqueous solution containing ammonium biborate to obtain a deposit of 2% by mass of B203. After maturation at ambient temperature in an atmosphere saturated with water, the impregnated extrudates are dried overnight at 120 ° C. and then calcined at 550 ° C. for 2 hours in dry air. A catalyst named NU86MoB is obtained. In the same way, a NU86MoSi catalyst was then prepared by impregnating the NU86Mo catalyst with an emulsion of Rhodorsil EP1 silicone (Rhone-Poulenc) so as to deposit 1.6% of SiO2. The impregnated extrudates are then dried

  overnight at 120 C and then calcined at 550 C for 2 hours in dry air.

  Finally, a NU86MoBSi catalyst was obtained impregnating the NU86Mo catalyst with an aqueous solution containing ammonium biborate and the Rhodorsil EP1 silicone emulsion (Rhone-Poulenc). The impregnated extrudates are then dried

  overnight at 120 C and then calcined at 550 C for 2 hours in dry air.

  The support extrudates of Example 1 are impregnated to dryness with an aqueous solution of a mixture of ammonium heptamolybdate and nickel nitrate, dried overnight at 120 ° C. in air and finally calcined in air at 550 ° C. Weight contents

  in NU86NiMo catalyst oxides obtained are indicated in Table 2.

  The support extrudates are impregnated to dryness with an aqueous solution of orthophosphoric acid, dried overnight at 120 ° C. in air and finally calcined in air at 550 ° C. The contents by weight of oxides of the NU86NiMoP catalyst obtained are shown in Table 2. We then impregnated the NU86NiMoP catalyst sample with an aqueous solution containing ammonium biborate. After maturation at room temperature in an atmosphere saturated with water, the impregnated extrudates are dried overnight at 120 ° C. and then calcined at 550 ° C. for 2 hours in dry air. A catalyst called NU86NiMoPB is obtained. A NU86NiMoPSi catalyst was obtained by the same procedure as the NU86NiMoPB catalyst above but by replacing in the impregnation solution the

  boron precursor by Rhodorsil EP1 silicone emulsion.

  Finally, a NU86NiMoPBSi catalyst was obtained by the same procedure as the above catalysts, but using an aqueous solution containing ammonium biborate and the Rhodorsil EP1 silicone emulsion. Fluorine is then added to this catalyst by impregnation with a dilute hydrofluoric acid solution so as to deposit approximately 1% by weight of fluorine. After drying overnight at 120 ° C. and calcination at 550 ° C. for 2 hours in dry air, the catalyst NU86NiMoPBSiF is obtained. The final oxide contents of the NU86NiMoP catalysts are

shown in Table 2.

  Table 2: Characteristics of NU86Mo and NU86NiMo catalysts NU86Mo catalyst NU86Mo NU86Mo NU86Mo __ _ __ _ _ _B Si BSi MoO3 (% wt) 14.6 14.3 14.3 14.1

_ I

  B203 (% wt) 0 1.8 0 1.6 SiO2 (% wt) 15.2 14.9 16.6 16.1 100% supplement 70.2 68.9 69.1 67.9 consists mainly of AI90 , (% wt) Catalyst NU86 NU86 NU86 NU86 NU86NiMo NU86NiMo NiMo NiM NiMo NiMo PBSi PBSiF P PB PSi MoO3 (% wt) 14.1 13.4 13.2 13.2 12.9 12.8 NiO (% wt) 3 , 2 3.1 3.0 3.0 2.9 2.9 P205 (% wt) 0 4.1 4.1 4.1 4.0 4.0 B203 (% wt) 0 0 2.0 0 1 , 9 1.9: i SiO2 (% wt) overall 14.7 14.1 13.8 15, 5 15.2 14.9 F (% wt) 0 0 0 0 0 1.1 Complement to 100% 68, 0 65.3 63.9 64.2 63.1 62.4 (mainly composed of AlIOI3 (% wt) i I The catalyst NU86NiMoP was then impregnated with an aqueous solution containing manganese nitrate. After maturation at room temperature in an atmosphere saturated with water, the impregnated extrudates are dried overnight at 1200C and then calcined at 550C for 2 hours in dry air. A catalyst called NU86NiMoPMn is obtained. This catalyst is then impregnated with an aqueous solution containing ammonium biborate m and the Rhodorsil EP1 silicone emulsion (Rhone-Poulenc). The impregnated extrudates are then dried overnight at 120 ° C. and then calcined at 550 ° C. for 2 hours in dry air and the catalyst NU86NiMoPMnBSi is obtained. Fluorine is then added to this catalyst by impregnation with a dilute hydrofluoric acid solution so as to deposit approximately 1% by weight of fluorine. After drying overnight at 120 ° C. and calcination at 550 ° C. for 2 hours in dry air, the catalyst NU86NiMoPMnBSiF is obtained. The weight contents of these catalysts are indicated

in Table 2bis.

  Catalyst NU86NiMo NU86NiMo NU86NiMo PMn PMnBSi PMnBSiF MoO3 (% wt) 13.2 12.7 12.6 NiO (% wt) 3.0 2.9 2.9 MnO2 (% wt) 2.1 2.0 2.0 P2s05 (% wt) 4.1 3.95 3.9 B203 (% wt) 0 1.9 1.9 SiO2 (% wt) overall 13.8 14.8 14.7 F (% wt) 0 0 1.1 Complement at 100% 63.8 61.75 60.9 (mainly composed of Al2OR (% wt) Table 2bis: Characteristics of NU86NiMo catalysts containing manganese Analysis, by electron microprobe, of catalysts NU86NiMoPSi, NU86NiMoPBSi, NU86NiMoPBSiF (Table 2 ) and catalysts NU86NiMoPMnBSi, NU86NiMoPMnBSiF (Table 2a) shows that the silicon added to the catalyst according to the invention is mainly located on the matrix and is in the form of silica

amorphous.

  Example 3 Preparation of a Support Containing a Nu-86 Zeolite and a Silica

  alumina We produced a silica-alumina powder by coprecipitation with a composition of 2% SiO2 and 98% A1203. A hydrocracking catalyst support containing this silica-alumina and the Nu-86 zeolite of Example 1 was then manufactured. For this, 19.7% by weight of the Nu-86 zeolite of Example 1 is used, which is mixed with 80.3% by weight of a matrix composed of the silica alumina prepared above. This powder mixture was then mixed with an aqueous solution containing 66% nitric acid (7% weight of acid per gram of dry gel) and then kneaded for 15 minutes. At the end of this kneading, the dough obtained is passed through a die having cylindrical orifices with a diameter equal to 1.4 mm. The extrudates are then dried overnight at 120 ° C. and then calcined at 550 ° C.

for 2 hours in air.

  Example 4 Preparation of Hydrocracking Catalysts Containing a NU- Zeolite

  86 and a silica-alumina The support extrudates containing a silica alumina and a Nu-86 zeolite of Example 3 are dry impregnated with an aqueous solution of a mixture of ammonium heptamolybdate, nickel nitrate and orthophosphoric acid, dried overnight at 120 ° C. in air and finally calcined in air at 550 ° C. The contents by weight of oxides of the catalyst NU86SiAI-NiMoP obtained are indicated in

table 3.

  We impregnated the NU86-SiAI-NiMoP catalyst sample with an aqueous solution containing ammonium biborate so as to impregnate 2% by mass of B203. After maturation at room temperature in an atmosphere saturated with water, the impregnated extrudates are dried overnight at 120 ° C. and then calcined at

  550 C for 2 hours in dry air. We obtain a catalyst named NU86SiAI-

  NiMoPB which therefore contains silicon in the silica-alumina matrix.

  The characteristics of the NU86-SiAI-NiMo catalysts are summarized in Table 3. Table 3: Characteristics of the NU86-SiAI-NiMo catalysts

Catalyst NU86- NU86-

SiAI- SiAI-

NiMo NiMo

P PB

  MoO3 (% wt) 13.4 13.3 NiO (% wt) 3.0 2.8 P205 (% wt) 4.2 4.1 B203 (% wt) 0 2.0 SiO2 (% wt) 15.5 15.2 Complement at 100% 639 626 composed mainly of A1203 (% wt) Example 5: Preparation of a hydrocracking catalyst support containing a NU-87 zeolite The raw material used is a NU-87 zeolite, which has a overall Si / AI atomic ratio equal to 17.2, a sodium content by weight corresponding to an Na / AI atomic ratio equal to 0.144. This NU-87 zeolite was synthesized from the

  European patent application EP-A-0.377.291.

  This NU-87 zeolite first undergoes so-called dry calcination at 550 ° C. under dry air flow for 6 hours. Then the solid obtained is subjected to four ionic exchanges in a NH4NO3 10ON solution, at approximately 100 ° C. for 4 hours for each exchange. The solid thus obtained is referenced NH4-NU-87 and has a

  Si / AI ratio = 17.4 and an Na / AI ratio = 0.002. Its other physical and

  chemicals are grouped in Table 4.

Table 4

  X-ray diffraction sample: Adsorption parameters a b c B V Crist. (SBET V (3) S E. I V2 / q (A) _ (A) (A) () (A3) (%) (m2 /) 1

  NH4-NU-87 14.35 22.34 25.14 151.53 3,840 100,466 10.19

  (1) Crystallinity, (2) V at P / Po = 0.19 in ml liquid N2 / g A hydrocracking catalyst support containing a NU-87 zeolite is produced as follows: 20% by weight of a NU-87 zeolite which is mixed with% by weight of alumina of type SB3 supplied by the company Condéa. The kneaded dough is then extruded through a die with a diameter of 1.4 mm. The extrudates are

  then dried overnight at 120 C in air and then calcined at 550 C in air.

  Example 6 Preparation of Hydrocracking Catalysts Containing an NU-87 Zeolite The support extrudates containing an NU-87 zeolite from Example 5 are dry impregnated with an aqueous solution of ammonium heptamolybdate, dried overnight at 120 ° C. C in air and finally calcined in air at 550 C. Weight contents

  in oxides of the catalyst NU87Mo obtained are indicated in table 5.

  The NU87Mo catalyst was then impregnated with an aqueous solution containing ammonium biborate to obtain a deposit of 1.8% by mass of B203. After maturation at ambient temperature in an atmosphere saturated with water, the impregnated extrudates are dried overnight at 120 ° C. and then calcined at 550 ° C. for 2 hours in dry air. A catalyst named NU87MoB is obtained. In the same way, a NU87MoSi catalyst was then prepared by impregnating the NU87Mo catalyst with an emulsion of Rhodorsil EP1 silicone (Rhone-Poulenc) so as to deposit 1.5% of SiO2. The impregnated extrudates are then dried

  overnight at 120 C and then calcined at 550 C for 2 hours in dry air.

  Finally, a NU87MoBSi catalyst was obtained impregnation of the NU87No catalyst with an aqueous solution containing ammonium biborate and the silicone emulsion Rhodorsil EP1 (Rhone-Poulenc). The impregnated extrudates are then dried

  overnight at 120 C and then calcined at 550 C for 2 hours in dry air.

  The extrudates of Example 5 above are impregnated to dryness with an aqueous solution of a mixture of ammonium heptamolybdate and nickel nitrate, dried overnight at 120 ° C. in air and finally calcined in air at 550 ° C. The oxide contents by weight of the catalyst NU87NiMo obtained are given in Table 5. The extrudates are impregnated to dryness with an aqueous solution of a mixture of ammonium heptamolybdate, nickel nitrate and orthophosphoric acid, dried one night at 120 ° C. in air and finally calcined in air at 550 ° C. The contents by weight of oxides of the NU87NiMoP catalyst obtained are indicated in the

table 5.

  We then impregnated the NU87NiMoP catalyst sample with an aqueous solution containing ammonium biborate. After maturation at room temperature in an atmosphere saturated with water, the impregnated extrudates are dried overnight at 120 ° C. and then calcined at 550 ° C. for 2 hours under

  dry air. A catalyst named NU87NiMoPB is obtained.

  A NU87NiMoPSi catalyst was obtained by the same procedure as the NU87NiMoPB catalyst above but by replacing the impregnation solution with the

  boron precursor by Rhodorsil EP1 silicone emulsion.

  Finally, a NU87NiMoPBSi catalyst was obtained by the same procedure as the above catalysts but using an aqueous solution containing ammonium biborate and the Rhodorsil EP1 silicone emulsion. Fluorine is then added to this catalyst by impregnation with a dilute hydrofluoric acid solution so as to deposit approximately 1% by weight of fluorine. After drying overnight at C and calcination at 550 C for 2 hours in dry air, the catalyst NU87NiMoPBSiF is obtained. The final oxide contents of the NU87NiMo catalysts are

shown in Table 5.

  Table 5: Characteristics of the NU87Mo and NU87NiMo catalysts Catalyst NU87Mo NU87Mo NU87Mo NU87Mo B Si BSi MoO3 (% wt) 14.3 14.0 14.0 13.8 B203 (% wt) 0 1.9 0 1.8 SiO2 (% wt) 15.4 15.1 16.6 16.3 Supplement a. 10oo% Complement to 100% 70.3 69.0 69.3 68.1 mainly composed of Al90, (% wt) Catalyst NU87 NU87N NU87 NU87 NU87Ni NU87Ni NiMo iMo NiMo NiMo Mo Mo P PB PSi PBSi PBSiF MoO3 (% wt) 13.4 13.4 13.1 13.1 12.9 12.8 NiO (% wt) 3.1 3.1 3.1 3.1 3.0 3.0 P205 (% wt) 0 4.35 4.3 4.2 4.2 4.2 B203 (% wt) 0 0 1.8 0 1.7 1.7 SiO2 (% wt) overall 14.8 14.3 14.0 15.5 15.3 15.1 F (% wt) 0 0 0 0 0 0.9 Complement a to 100% 68.7 64.85 63.7 64.1 62.9 62.3 (mainly composed of AlIO2 (% wt) The catalyst NU87NiMoP was then impregnated with an aqueous solution containing manganese nitrate After maturation at ambient temperature in an atmosphere saturated with water, the impregnated extrudates are dried overnight at 120 ° C. and then calcined at 550 ° C. for 2 hours in dry air. A catalyst named NU87NiMoPMn is obtained. This catalyst is then impregnated with an aqueous solution containing ammonium biborate and the silicone emulsion Rhodorsil EP1 (Rhone-Poulenc). The impregnated extrudates are then dried overnight at 120 ° C. and then calcined at 550 ° C. for 2 hours in dry air and the catalyst NU87NiMoPMnBSi is obtained. Fluorine is then added to this catalyst by impregnation with a dilute hydrofluoric acid solution so as to deposit approximately 1% by weight of fluorine. After drying overnight at 120 ° C. and calcination at 550 ° C. for 2 hours in dry air, the catalyst NU87NiMoPMnBSiF is obtained. The weight contents of these catalysts are indicated

in Table 5bis.

  Catalyst NU87Ni NU87Ni NU87Ni Mo Mo Mo PMn PMnBSi PMnBSi F MoO3 (% wt) 13.1 12.7 12.6 NiO (% wt) 3.1 3.0 2.9 MnO2 (% wt) 1.9 1.8 1.8 P205 (% wt) 4.3 4.1 4.1 B203 (% wt) 0 1.9 SiO2 (% wt) overall 13.9 14.8 14.7 F (% wt) 0 0 0, 9 Complement at 100% 63.7 61.7 61.1 (mainly composed of Al203 (% wt) Table 5bis: Characteristics of NU87NiMo catalysts containing 1 0 manganese Analysis, by electron microprobe, of catalysts NU87NiMoPSi, NU86NiMoPBSi, NU86NiMoPBSiF (Table 5) and catalysts NU87NiMoPMnBSi, NU87NiMoPMnBSiF (Table 5 bis) shows that the silicon added to the catalyst according to the invention is mainly located on the matrix and is in the form of amorphous silica.

  Example 7 Preparation of a Support Containing a Nu-87 Zeolite and a Silica

  alumina We produced a silica-alumina powder by co-precipitation with a composition of 4% SiO2 and 96% A1203. A hydrocracking catalyst support containing this silica-alumina and the Nu-87 zeolite of Example 5 was then manufactured. For this, 20.1% by weight of the Nu-87 zeolite of Example 5 is used, which is mixed with 79.9% by weight of a matrix composed of the silica alumina prepared above. This powder mixture was then mixed with an aqueous solution containing 66% nitric acid (7% weight of acid per gram of dry gel) and then kneaded for 15 minutes. At the end of this kneading, the dough obtained is passed through a die having cylindrical orifices with a diameter equal to 1.4 mm. The extrudates are then dried overnight at 120 ° C. and then calcined at 550 ° C.

for 2 hours in air.

  Example 8 Preparation of Hydrocracking Catalysts Containing a NU- Zeolite

  87 and a silica-alumina The support extrudates containing a silicon alumina and a Nu-87 zeolite of Example 7 are. dry impregnated with an aqueous solution of a mixture of ammonium heptamolybdate, nickel nitrate and orthophosphoric acid, dried overnight at 120 ° C. in air and finally calcined in air at 550 ° C. Weight contents of oxides of the NU87-SiAI-NiMoP catalyst obtained are indicated in

table 6.

  We impregnated the NU87-SiAI-NiMoP catalyst sample with an aqueous solution containing ammonium biborate so as to impregnate 2% by mass of B203. After maturation at room temperature in an atmosphere saturated with water, the impregnated extrudates are dried overnight at 120 ° C. and then calcined at

  550 C for 2 hours in dry air. We obtain a catalyst named NU87SiAI-

  NiMo PB which therefore contains silicon in the silica-alumina matrix.

  The characteristics of the NU87-SiAI-NiMo catalysts are summarized in Table 6. Table 6: Characteristics of the NU87-SiAI-NiMo catalysts

Catalyst NU87-SiAI- NU87-SiAI-

NiMo NiMo

P PB

  MoO3 (% wt) 13.4 13.1 NiO (% wt) 3.0 2.9 P205 (% wt) 4.2 4.1 B203 (% wt) 0 2.0 SiO2 (% wt) 16.4 16.1 Complement at 100% 631 61.9 mainly composed of A1203 (% wt) Example 9: Comparison of hydrocracked catalysts of a gas oil under vacuum at

partial conversion.

  The catalysts, the preparations of which are described in the preceding examples, are used under the conditions of hydrocracking at moderate pressure on an oil charge, the main characteristics of which are as follows: Density (20/4) 0.921 Sulfur (% by weight) 2.46 Nitrogen (ppm weight) 1130 Simulated distillation initial point 365 C point 10% 430 C point 50% 472 C point 90% 504 C end point 539 C pour point + 39 C The catalytic test unit includes two reactors in fixed bed , with upward flow of the charge ("up-flow"). In the first reactor, that in which the charge passes first, the catalyst for the first hydrotreatment stage HTH548 is sold, sold by the company Procatalyse comprising an element from group VI. and an element from group VIII deposited on alumina. In the second reactor, the one in which the charge passes last, a hydrocracking catalyst described above is introduced. rs, 40 ml of catalyst are introduced. The two reactors operate at the same temperature and at the same pressure. The operating conditions of the test unit are as follows: Total pressure 5 MPa Hydrotreating catalyst 40 cm3 Hydrocracking catalyst 40 cm3 Temperature 400 C Hydrogen flow rate 20 I / h Charging flow rate 40 cm3 / h

  The two catalysts undergo an in-situ sulfurization step before reaction.

  Note that any in-situ or ex-situ sulfurization method is suitable. Once

  the sulfurization carried out, the charge described above can be transformed.

  The catalytic performances are expressed by the gross conversion at 400 ° C. (CB), by the gross selectivity for middle distillates (SB) and by the conversions to hydrodesulfurization (HDS) and in hydrodenitrogenation (HDN). These catalytic performances are measured on the catalyst after a stabilization period,

  generally at least 48 hours, has been respected.

* The gross conversion CB is taken equal to minus CB =% wt of 380 C of the effluent The gross selectivity SB to middle distillates is taken equal to: minus SB = 100 * weight of the fraction (150 C-380 C) / weight of the 380 C fraction of the effluent The conversion to HDS hydrodesulfurization is taken equal to HDS = (Sinitial - Seffluent) / Sinitial * 100 = (24600 Seffluent) / 24600 * 100 The conversion to HDN hydrodenitrogenation is taken equal to: HDN = (Ninitial - Neffluent) / Ninitial * 100 = (1130 Neffluent) / 1130 * 100 In the following table, we have reported the gross conversion CB to 400 C, the gross selectivity SB, the conversion to hydrodesulfurization HDS and the conversion to

  HDN hydrodenitrogenation for catalysts.

  Table 7 Catalytic activities of catalysts in partial drocrack at 400 C

CB SB HDS (%) HDN (%)

  (% wt) NiMo / NU-86-AI 49.6 59.7 98.7 95.7 NiMoP / NU- 86-AI 49.6 60.2 99.3 96.2 NiMoPB / NU-86-AI 49 , 9 61.3 99.4 97.1 NiMoP / Nu86-SiAI 49.7 59.5 98.3 95.5 NiMoPB / Nu86-SiAI 46.2 59.9 98.1 97.7 NiMoPSi / NU-86 -AI 50.2 59.9 1 99.6 97.9 NiMoPBSi / NU-86- AI 50.5 60.4 99.7 98.1 NiMo / NU-87-AI] 47.7 68.1 98, 6 95.0 NiMoP / NU-87-AI 47.8 68.2 99.1 95.3 NiMoPB / NU-87-AI 48.4 68.4 99.3 96.4 NiMoP / Nu87- SiAI 46.7 69.5 98.3 95.5 NiMoPB / Nu87-SiAI 46.2 68.3 98.1 96.3 NiMoPSi / NU-87-AI 48.6 68.9 99.4 98.1 NiMoPBSi / NU-87 -AI 49.1 68.1 | 99.6 | 98.3 J The results in Table 7 show that the addition of B and / or Si to the NiMo / NU-86 or NiMo / NU-87 and NiMoP / catalysts NU-86 or NiMoP / NU-87 provides an improvement in the performance of the catalyst in conversion whatever the zeolite of the NU-86 and NU-87 groups. Indeed, the catalysts according to the invention (NU87NiMoB, NU87NiMoSi, NU87NiMoPBSi, NU87NiMoB, NU87NiMoSi and NU87NiMoPBSi) have a higher activity, that is to say higher conversions for the same temperature reaction of 400 C, than the catalysts non-compliant (NU87NiMo, NU87NiMoP and NU87NiMo e NU87NiMoP). The catalysts of the invention containing boron and / or silicon are therefore particularly advantageous for the partial hydrocracking of feedstocks of the vacuum distillate type.

  containing nitrogen at moderate hydrogen pressure.

  In addition, the results in Table 7 show that it is advantageous to introduce silicon onto the already prepared catalyst (NU87NiMo and NU87NiMo series) rather than in the form of a support containing silicon obtained from a silica-alumina. (NU87-SiAI-NiMo and NU86-SiAINiMo series). It is therefore particularly advantageous to introduce silicon onto a precursor already containing the elements of group VIB and / or VIII and optionally at least one of the elements P, B and F. Example 10: Comparison of the catalysts in hydrocracking of a high conversion vacuum diesel fuel The catalysts whose preparations are described in the previous examples are used under the conditions of high conversion hydrocracking (60-100%). The petroleum charge is a hydrotreated vacuum distillate, the main characteristics of which are as follows Density (20/4) 0.869 Sulfur (ppm weight) 502 Nitrogen (ppm weight) 10 Simulated distillation initial point 298 C point 10% 369 C point 50% 427 C point 90% 481 C end point 538 C This charge was obtained by hydrotreating a distillate under vacuum on an HR360 catalyst sold by the company Procatalyse comprising an element of

  group VIB and an element of group VIII deposited on alumina.

  0.6% by weight of aniline and 2% by weight of dimethyldisulphide are added to the charge in order to simulate the partial pressures of H2S and NH3 present in the second hydrocracking step. The charge thus prepared is injected into the hydrocracking test unit which comprises a fixed bed reactor, with upward circulation of the charge ("up-flow"), into which 80 ml of catalyst is introduced. The catalyst is sulfurized by an n-hexane / DMDS + aniline mixture up to 320 C. It should be noted that any in-situ or ex-situ sulfurization method is suitable. Once the sulfurization has been carried out, the charge described above can be transformed. The operating conditions of the test unit are as follows Total pressure 9 Mpa Catalyst 80 cm3 Temperature 360-420 C Hydrogen flow 80 I / h Charging flow 80 cm3 / h The catalytic performance is expressed by the temperature which allows '' reach a gross conversion level of 70% and by gross selectivity to distillates 150-380 C. These catalytic performances are measured on the catalyst after a stabilization period, generally at least 48 hours,

has been respected.

  The gross conversion CB is taken equal to: less CB =% wt of 380 C minus the effluent minus 380 C represents the fraction distilled at a temperature less than or equal to

380 C.

  The gross selectivity SB in middle distillate is taken equal to: less SB = 100 * weight of the fraction (150 C-380 C) / weight of the fraction 380 C of the effluent The reaction temperature is fixed so as to reach a gross conversion CB equal to 70% by weight. In Table 8 below, we have reported the reaction temperature and the raw selectivity for the catalysts described in Tables 3 and 3a,

4 and 4 bis.

Table 8

  Catalytic activities of high conversion hydrocracking catalysts (70%)

T (C) SB

  NiMo / NU-86 373 36.0 NiMoP / NU-86 371 36.2 NiMoPB / NU-86 370 36.3 NiMoPSi / NU-86 369 37.4 NiMoPBSi / NU-86 367 36.3 NiMoPBSiF / NU-86 365 37.1 NiMoPMn / NU-86 371 37.3 NiMoPMnBSi / NU-86 368 37.1 NiMoPMnBSiF / NU-86 365 37.4 NiMo / NU-87 384 30.6 NiMoP / NU-87 383 32.5 NiMoPB / NU-87 380 32.9 NiMoPSi / NU-87 379 32.7 NiMoPBSi / NU-87 378 32.3 NiMoPBSiF / NU-87 376 _34.4 NiMoPMn / NU-87 380 32.9 NiMoPMnBSi / NU-87 378 33.4 NiMoPMnBSiF / NU-87 375 34.1 MB / NU- 86 373 34.1 MBB / NU-86 373 33.9 MoSi / NU- 86 372 33.0 MoBSi / NU-86 371 33, MB / NU -87 385 30.6 MoB / NU-87 384 30.3 MoSi / NU-87 I 383 29.6 MoBSi / NU-87 383 29.1 The addition of boron and / or silicon to catalysts containing a zeolite of group NU-86 and NU-87 makes it possible to improve the activity in conversion, which results in a reduction in the reaction temperature necessary to reach 70% of conversion. In addition, if manganese and / or fluorine are added, there is also an improvement in the converting activity with a marked improvement in the raw selectivity for middle distillates. This effect is attributed to a hydrogenating function exalted by the dopants Mn and / or F. The catalysts containing zeolite NU-86 or Nu-87 of the invention containing boron and silicon are therefore particularly advantageous for hydrocracking at high distillate charge conversion under vacuum at moderate hydrogen pressure.

Claims (13)

  1. Catalyst containing a support containing at least one matrix, at least one zeolite chosen from zeolite NU-86 and zeolite NU-87, said catalyst additionally containing at least one metal chosen from the group formed by the metals of groups VIB and the metals of group VIII of the periodic table, said catalyst being characterized in that it contains, as promoter, at least one element chosen from the group formed by silicon and boron. 2. Catalyst according to claim 1 characterized in that it also contains phosphorus.   3. Catalyst according to one of claims 1 to 2 characterized in that it contains in   in addition to at least one element chosen from group VIIA of the periodic table   4. Catalyst according to one of claims 1 to 3 characterized in that it contains in   in addition to at least one element chosen from group VIIB of the classification of the elements.   5. Catalyst according to one of claims 1 to 4 characterized in that the silicon is introduced in amorphous form.   6. Catalyst according to one of claims 1 to 5 in which the zeolite is under hydrogen form.   7. Catalyst according to one of claims 1 to 6 containing by weight relative to the   catalyst * 0.1 to 60% of at least one metal chosen from the group formed by the metals of group VIB and of group VIII * 0.1 to '0% of at least one zeolite chosen from zeolite NU-86 and the zeolite NU-87 * 0.1 to 99% of at least one amorphous or poorly crystallized mineral matrix * 0.1 to 20% of at least one promoter element chosen from the group formed by boron and silicon * 0 to 20% of phosphorus * 0 to 20% of at least one element chosen from group VIIA * 0 to 20% of at least one element chosen from group VIIB   8. Method for preparing a catalyst according to one of claims 1 to 7 in   which a) drying and weighing a solid hereinafter called a precursor, containing at least the following compounds: at least one matrix, at least one zeolite chosen from zeolite NU-86 and zeolite NU-87, at least one element of the group formed by the elements of group VIB and of group VIII, the whole being preferably shaped b) the solid precursor defined in step a) is impregnated with at most one aqueous solution containing at least one element chosen from boron and silicon c) the wet solid obtained in step b) is allowed to stand under a humid atmosphere at a temperature between 10 and 80 ° C., d) the solid obtained in step c) is dried at a temperature between 60 and 150 C   e) the solid obtained in step d) is calcined at a temperature of between 150 and 800 ° C. 9. A process for the preparation of a catalyst according to claim 8, which is also introduced in step b) at least an element chosen from phosphorus, the elements   of the VIIA group and the elements of the VIIB group.   1O. Process for preparing a catalyst according to one of claims 8 to 9 in   which is calcined and dried between each impregnation of an element.   11. Use of a catalyst according to one of claims 1 to 7 or preparation according to   one of claims 7 to 9 in a hydrocracking process for charges   hydrocarbons. 12. Use according to claim 11 such that the load consists of at least   80% by volume of compounds whose boiling points are at least 350 C.   13. Use according to one of claims 11 to 12 such that the temperature is   greater than 200 C, under a pressure greater than 0.1 Mpa, with a hydrogen recycling rate greater than 50 normal liters of hydrogen per liter of   load and with a wvvh between 0.1 and 20 h-1.   14.Use according to one of claims 11 to 13 in a method   partial hydrocracking, with a conversion level of less than 55%.   15. Use according to claim 14 such that the temperature is greater than or equal to 230 C, under a pressure greater than 2 Mpa, with an amount of hydrogen greater than 100 normal liters of hydrogen per liter of charge, with a volume speed hourly between 0.1 and 1 Oh-1   16. Use according to one of claims 11 to 13 in a process   hydrocracking with a conversion level greater than 55% 17. Use according to claim 16 such that the temperature is greater than or equal to 230 C, under a pressure greater than 5 Mpa, with an amount of hydrogen greater than 100 normal liters of hydrogen per liter of charge, with   an hourly volume speed between 0.15 and 1 Oh-1.   18. Use according to one of claims 11 to 17 in which a   prior hydrotreatment step at a temperature between 350 and 460 ° C., under pressure greater than 3 Mpa, with a quantity of hydrogen greater than 100 normal liters of hydrogen per liter of charge, with a volume speed   schedule between 0.1 and 5h-1 in the presence of a hydrotreating catalyst.