FR2780309A1 - Hydrocracking catalyst for production of light petroleum fractions from heavy residues - Google Patents

Abstract

The catalyst may include mixed sulfide phases containing sulfides of groups VB and VIB elements to increase the acidity of the matrix and improve selectivity in middle distillates. The catalyst comprises an amorphous matrix of oxide-type, a group VB element, a beta zeolite, a promoter element (boron, phosphorus or silicon) and a group VIB or VIII element. In addition a catalyst is claimed comprising a beta zeolite, a mineral matrix, a mixed sulfide phase containing sulfur and metals of groups VB and VIB and optionally a group VIII metal, silicon, boron or phosphorus and a group VIIA element. An Independent claim is also included for the preparation of the catalyst by: (a) drying and weighing of a precursor solid containing a matrix, a beta zeolite, and optionally the promoter element, group VIB or VIII elements and group VIIa element, the whole being formed; (b) calcining the dry solid at a minimum of 150 deg C; (c) impregnating the calcined solid with a solution containing a group VB element, preferably niobium; (d) leaving the moist solid in a moist atmosphere at 10-120 deg C; (e) drying the moist solid at 60-150 deg C; and (f) calcining the dried solid at a minimum of 150 deg C, preferably 250 deg C. The catalysts is sulfurized in a mixture of H2 / H2S or pure H2S at 150 - 800 deg C.

Description

The present invention relates to a charge hydrocracking catalyst

  hydrocarbon, said catalyst comprising at least one amorphous or poorly crystallized oxide-type matrix, at least one element (metal) of group VB (group 5 according to the new notation of the periodic classification of elements: Handbook of Chemistry and Physics, 76th edition, 19951996, inside front cover) preferably niobium, at least one beta zeolite, at least one promoter element chosen from the group consisting of boron, phosphorus and silicon, possibly at least one element (metal) chosen from group VIB and / or group VIII (group 6 and groups 8, 9 and 10 according to the new notation of the periodic table of the elements), preferably molybdenum and tungsten, cobalt, nickel and iron. The catalyst also optionally contains at least one element of group VIIA (halogen group, group 17 according to the new notation of the periodic classification of elements), such as for example

fluorine.

  The present invention also relates to the processes for preparing said catalyst, as well as its use for hydrocracking hydrocarbon feedstocks such as petroleum cuts, cuts derived from coal containing aromatic, and / or olefinic, and / or naphthenic compounds, and / or paraffinics, the said fillers possibly containing metals, and / or

  nitrogen, and / or oxygen and / or sulfur.

  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 all 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), combinations of boron and aluminum oxides , amorphous silica-aluminas and clays. 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, or by a combination of at least one metal from group VI of the periodic table such as molybdenum and tungsten 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 which are not very active, working at a generally high temperature (greater than or equal to 390 ° C.), and at a low space supply speed (the VVH expressed in volume of charge to be treated per unit catalyst volume 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.

  On the other hand, simple sulfides of elements from group VB have been described as constituents of hydrorefining catalysts for hydrocarbon feedstocks, such as, for example, niobium trisulfide in US Pat. No. 5,294,333. Mixtures of simple sulphides comprising at least one element from group VB and one element from group VIB have also been tested as constituents of hydrorefining catalysts for hydrocarbon feedstocks, as for example in the patent

  US-A-4,910,181 or US-A-5,275,994.

  The research carried out by the applicant on zeolites and on the hydrogenating active phases, led him to discover that, surprisingly, a catalyst for hydrocracking hydrocarbon feedstocks comprising at least one generally porous amorphous or poorly crystallized matrix such that alumina, at least one element from group VB of the periodic table of elements, such as tantalum, niobium and vanadium, preferably niobium, at least one beta zeolite, at least one promoter element chosen from the group constituted by the

boron, phosphorus and silicon.

  The catalyst according to the invention contains at least one beta zeolite, preferably at least partially in hydrogen form. By beta zeolite is meant BEA structural type zeolites as described in the work "<Atlas of Zeolite Structure Types", W.M. Meier, D.H. Olson and Ch. Baerlocher, 4th revised edition,

1996, Elsevier.

  The catalyst also optionally comprises at least one element from group VIB of the said classification, such as chromium, molybdenum and tungsten, preferably molybdenum or tungsten, even more preferably molybdenum, optionally an element from group VIII, that is to say an element chosen from the group consisting of: Fe, Ru, Os, Co, Rh, Ir, Ni, Pd, Pt, preferably iron, cobalt, nickel or ruthenium, optionally a element of group VIIA, preferably fluorine. Said catalyst has a greater hydrocracking activity than those of catalytic formulas based on element of group VIB

known from the prior art.

  The catalyst of the present invention generally contains in% by weight relative to the total mass of the catalyst: - 0.1 to 99.8%, preferably from 0.1 to 90%, even more preferably from 0.1 to 80%, and very preferably 0.1 to 70% of at least one beta zeolite, - 0.1 to 60%, preferably 0.1 to 50%, and even more preferably 0.1 at 40%, of at least one element chosen from the group VB, - 0.1 to 99%, preferably from 1 to 99% of at least one porous amorphous or poorly crystallized mineral matrix of oxide type - 0.1 at 20%, preferably from 0.1 to 15% and even more preferably from 0.1 to 10% of at least one promoter element chosen from the group consisting of boron, phosphorus, and silicon, not including the silicon optionally contained in the zeolite, the catalyst possibly also containing: - from 0 to 60%, preferably from 0.1 to 50% and even more preferably from 0.1 to 40% of at least oneelement chosen from elements of group VIB and group VIII, and - from 0 to 20%, preferably from 0.1 to 15% and even more preferably from 0.1

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

  When present, the silicon promoter element is in amorphous form and located mainly on the matrix. The elements of group VB, VIB and group VIII of the catalyst of the present invention may be present in whole or in part

  in metallic and / or oxide and / or sulfide form.

  The catalysts according to the invention can be prepared by any method

known to those skilled in the art.

  A preferred process for the preparation of the catalyst according to the present invention comprises the following steps: a) a solid called the precursor is dried and weighed, containing at least the following compounds: at least one matrix, at least one beta zeolite, optionally at least a promoter element chosen from the group consisting of boron, phosphorus, and silicon, optionally at least one element chosen from elements of group VIB and group VIII, optionally at least one element of group VIIA, the whole preferably being shaped, b) the dry solid obtained in step a) is calcined at a temperature of at least 150 C,

preferably at least 450 C.

  c) the solid precursor defined in step b) is impregnated with a solution containing at least one element of group VB, preferably niobium, d) the wet solid is allowed to stand under a humid atmosphere at a temperature between 10 and 120 C, e) the wet solid obtained in step d) is dried at a temperature between and 150 C, f) the dried solid is calcined in step e) in dry air at a temperature of at least

   C, preferably at least about 250 C.

  The solid obtained at the end of any of steps a) to e) may be impregnated with at least one solution containing all or part of at least one element chosen by the elements of group VIB and of group VIII, optionally at least one promoter element chosen from the group consisting of boron, phosphorus and silicon and

  optionally at least one element of the VIIA group.

  The preparation of the precursor of step a) above can be carried out according to all the conventional methods of a person skilled in the art. According to a preferred preparation process, the precursor is obtained by mixing at least one matrix and at least one beta zeolite, then shaped, dried and calcined. The promoter element (s) chosen from the group consisting of boron, phosphorus, and silicon, that or those chosen from elements from groups VIB, VIII, and / or from elements from group VIIA, are then introduced by any method known to those skilled in the art, in any of steps a) to e), before or after shaping and

  before or after the calcination of said mixture.

  The shaping can be carried out for example by extrusion, by pelletizing, by the oil drop method, by granulation on a turntable or by any other method well known to those skilled in the art. At least one calcination can be carried out after any one of the stages of the preparation, it is usually carried out in air at a temperature of at least 150 C, preferably at least 300 C. Thus, the product obtained at the end from step a) and / or from step e) and / or optionally after introduction of the element or elements chosen from elements of groups VIB, VIII, and / or from promoter elements of the group consisting of boron, phosphorus, and silicon, and / or among the elements of group VIIA, is then optionally calcined in air, usually at a temperature of at least 150 ° C., preferably at least 250 ° C., more preferably between approximately

350 and 1000 C.

  The hydrogenating element can be introduced at any stage of the preparation, preferably during mixing, or very preferably after shaping. The shaping is followed by a calcination, the hydrogenating element is introduced before or after this calcination. The preparation ends in all cases with a 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 in a wet alumina gel for a few tens of minutes, then in pass the dough thus obtained

  through a die to form extrudates with a diameter between 0.4 and 4 mm.

  The hydrogenating function can then 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 beta zeolite, with at least one 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 dispersed in at least one matrix, 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 (in particular molybdenum or tungsten) were previously introduced during the mixing of the support. Finally, it can be introduced by one or more operations for impregnating the calcined support consisting 215 of at least one beta zeolite and at least one matrix, with solutions containing the precursors of the metal oxides of groups VIB and / or VIII , the precursors of group VIII metal oxides being preferably introduced after those of

  VIB group or at the same time as these.

  Another preferred preparation method consists in introducing into a mixture of at least one matrix with at least one beta zeolite, before or after shaping and before or after the calcination of said mixture, at least one element of group VB, and

  at least one element chosen from elements from group VIII and group VIB.

  Preferably, the support is impregnated with an aqueous solution.

  The impregnation of the support is preferably carried out by the so-called "dry" impregnation method well known to those skilled in the art. The impregnation can be carried out in a single step by a solution containing all the constituent elements of the

final catalyst.

  Boron and / or phosphorus and / or silicon and optionally the element chosen from group VIIA of halide ions, preferably fluorine, can be introduced into the catalyst at various levels of the preparation according to any known technique of

the skilled person.

  A preferred method according to the invention consists in depositing, for example by

  impregnation, the promoter element (s) chosen, for example the boron-

  silicon on the precursor, calcined or not, preferably calcined. For this, an aqueous solution of at least one boron salt such as ammonium biborate or ammonium pentaborate is prepared in an alkaline medium and in the presence of hydrogen peroxide and a so-called dry impregnation is carried out, in which filling the pore volume of the precursor with the boron-containing solution. In the case where, for example, silicon is deposited, a solution of a silicon compound will be used, for example.

silicone type.

  The deposition of boron and silicon can also be carried out simultaneously using, for example, a solution containing a boron salt and a silicon compound of the silicone type. Thus, for example in the case where the precursor is a nickel-molybdenum type catalyst supported on alumina and zeolite chosen from the group consisting of beta zeolites, it is possible to impregnate this precursor with aqueous biborate solution. ammonium and silicone Rhodorsil El P from the company Rhône Poulenc, to carry out a drying for example at 80 C, then to impregnate with a solution of ammonium fluoride, to carry out a drying for example at 80 C, and carry out a calcination for example and preferably in air in a crossed bed, for example at 500 ° C. for 4 hours. We then deposit

  the element of the VB group according to any method known to those skilled in the art.

  The promoter element chosen from the group formed by boron, phosphorus and silicon, and the element chosen from halogens from group VIIA, can also be introduced by one or more impregnation operations, for example with

  excess solution, on the calcined precursor.

  Thus, for example, it is possible to impregnate the precursor with an aqueous solution of ammonium biborate and / or of silicone Rhodorsil E1 P from the company Rhône Poulenc to carry out a drying for example at 80 ° C., then to impregnate with a solution of ammonium fluoride, to carry out a drying for example at C, and to carry out a calcination for example and preferably in air in a crossed bed, for example at 500 C for 4 hours. Then the element of the

  VB group according to any method known to those skilled in the art.

  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 one of the promoter elements (B, P, Si), to dry, to calcine and then to impregnate the solid obtained with the solution containing another promoter element, to dry, to calcine. It is also possible to impregnate the precursor with a solution containing two of the promoter elements, to dry, to calcine and then to impregnate the solid obtained with the solution containing another promoter element, to dry, and to carry out a final calcination. The element of the group VB is then deposited according to

  any method known to those skilled in the art.

  The catalyst of the present invention may contain a group VIII element (metal) such as iron, cobalt, nickel, ruthenium, rhodium, palladium, osmium, iridium or platinum. Among the elements of group VIII, an element chosen from the group formed by iron, cobalt, nickel and ruthenium is preferably used. Of a

  advantageously, the following combinations of elements are used: nickel-

  niobium-molybdenum, cobalt-niobium-molybdenum, iron-niobium-molybdenum, nickel-

  niobium-tungsten, cobalt-niobium-tungsten, iron-niobium-tungsten, the preferred combinations being: nickel-niobium-molybdenum, cobaltniobium-molybdenum. It is also possible to use associations of four elements, for example nickel-cobalt-niobium-molybdenum. One can also use combinations containing a noble metal such as ruthenium-niobium-molybdenum, or ruthenium-nickel-niobiummolybdenum. In the case where the elements are introduced in several impregnations of the corresponding precursor salts, an intermediate calcination step of the catalyst

  will generally have to be carried out at a temperature between 250 and 600 C.

  The impregnation of 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 catalytic activity. Other compounds of

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

  The impregnation of niobium can be facilitated by adding oxalic acid and

  optionally ammonium oxalate in the solutions of niobium oxalate.

  Other compounds can be used to improve solubility and facilitate

  the impregnation of niobium as it is well known to those skilled in the art.

  The sulfurization can be done by any method known to those skilled in the art. The preferred method according to the invention consists in heating the non-calcined catalyst under

  flow of a hydrogen-hydrogen sulfide mixture or under flow of a nitrogen-mixture

  hydrogen sulphide or alternatively under pure hydrogen sulphide at a temperature between 150 and 800 C, preferably between 250 and 600 C, generally in

  a reaction zone with crossed bed.

  The porous mineral matrix, usually amorphous or poorly crystallized, generally consists of at least one refractory oxide in amorphous or poorly crystallized form. Said matrix is usually chosen from the group formed by alumina, silica, silica-alumina, or a mixture of at least two of the oxides mentioned above. We can also choose aluminates. It is preferred to use matrices containing alumina, in all these forms known to those skilled in the art.

  loom, for example gamma alumina.

  The sources of element of the VB group which can be used are well known to those skilled in the art. For example, among the sources of niobium, there can be used oxides, such as diniobium pentaoxide Nb2Os5, niobic acid Nb2Os.H20, niobium hydroxides and polyoxoniobates, niobium alkoxides of formula Nb (OR1) 3 o R1 is an alkyl radical, niobium oxalate NbO (HC204) 5, ammonium niobate. Preferably niobium oxalate or ammonium niobate is used. Among the beta zeolites, it is usually preferred to use beta zeolites whose overall atomic ratio, silicon / aluminum (Si / AI) is greater than approximately 10 and more preferably beta zeolites whose Si / AI ratio is between 10 and, and even more preferably between 10 and 150. These beta zeolites can

  be obtained by synthesis or by using any post-dealumination technique

  synthesis known to those skilled in the art.

  Advantageously, beta zeolites are used, either entirely under hydrogen form, or optionally partially exchanged with metal cations, for example cations of alkali or alkaline earth metals and / or rare earth cations with atomic number 57 to 71 inclusive (Zeolite Molecular Sieves Structure, Chemistry and Uses, DW Breck, J. Willey and sons, 1973). The cation / Al atomic ratio is generally less than 0.8, preferably less than 0.5 and even more preferably less than 0.1. The beta zeolites according to the invention preferably have a specific surface determined by the B.E.T. more than about 400 m2 / g, and more preferably

between 450 and 850 m2 / g.

  The sulfur source can be elemental sulfur, carbon sulfide, hydrogen sulfide, sulfur hydrocarbons such as dimethyl sulfide, dimethyl disulfide, mercaptans, thiophene compounds, thiols, polysulfides such as for example ditertiononylpolysulfide or TPS-37 from the company ATOCHEM, petroleum cuts rich in sulfur such as petrol, kerosene, diesel, alone or in mixtures with one of the sulfur compounds cited above. The

  preferred sulfur source is carbon sulfide or hydrogen sulfide.

  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.

  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. Silicon can also be added for example by impregnation of a silicon compound

  silicone type suspended in water.

  The source of boron can be boric acid, preferably orthoqric 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 means of an acid solution

  boric in a water / alcohol mixture.

  I! 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 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 sources of group VIII elements which can be used are well known to those skilled in the art. For example, for non-noble metals, nitrates, sulfates, phosphates, halides, for example chlorides, bromides and fluorides, carboxylates, for example acetates and carbonates, will be used. For noble metals, halides will be used, for example chlorides, nitrates, acids such as chloroplatinic acid, oxychlorides such as oxychloride

ruthenium ammonia.

  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 approximately 50 and approximately 600 m2 / g, a pore volume measured by mercury porosimetry of between approximately 0.2 and approximately 1.5 cm3 / g and a

  pore size distribution 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 C and preferably between 250 C and 480 C. The pressure is greater than 0.1 MPa and preferably greater than 1 MPa. The quantity of hydrogen is at least 50 and often between 80 and 5000 normal liters of hydrogen per liter of charge. The hourly space velocity is included in

  generally between 0.1 and 20 volume of feed 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 carried out by any method already described in the literature, either in situ, that is to say

  in the hydrocracking reactor, ie ex-situ.

  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 advantageously be used for the hydrocracking of sections of the distillate type under vacuum highly charged with sulfur and nitrogen, more particularly for example, sections with a sulfur content greater than

  0.1% by weight and with a nitrogen content greater than 10 ppm.

  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, preferably between 300 C and 480 C, and more preferably between 350 C and 450 C. The pressure preferably greater than 2 MPa , more preferably 3MPa, and preferably less than 12MPa, more preferably less than 10MPa. The amount of hydrogen is at least 100 normal liters of hydrogen per liter of charge, and preferably between 200 and 3000 normal liters of hydrogen per liter of charge. The hourly volume speed is preferably between 0.15 and 10 volume of feed per volume of catalyst and per hour. Under these conditions, the catalysts of the present invention exhibit better activity in conversion, in

  hydrodesulfurization and hydrodenitrogenation than commercial catalysts.

  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 stage. The catalyst of the first stage has a hydrotreatment function and comprises a matrix preferably based on alumina, and preferably not containing a zeolite, and at least one metal having a hydrogenating function. Said matrix is an porous amorphous or poorly crystallized oxide-type mineral matrix. Mention may be made, by way of nonlimiting example, of aluminas, silicas, silica-alumina. We can also choose aluminates. It is preferred to use matrices containing alumina, in all of these forms known to a person skilled in the art, and even more preferably alumina, for example gamma alumina. The hydrotreatment function is provided by at least one metal or group VIII metal compound such as nickel and cobalt in particular. It is possible to use a combination of at least one metal or compound of group VIB metal (for example molybdenum or tungsten) and of at least one metal or compound of group VIII metal (for example cobalt or nickel) of the Periodic Table of the Elements. The total concentration of metal oxides of groups VIB and VIII is preferably between 5 and 40% by weight and more preferably between 7 and 30% by weight and the weight ratio expressed as metal oxide (of metals) of group VIB on metal oxide (of metals) of group VIII is preferably between 1.25 and 20, and more preferably between 2 and 10. In addition, this catalyst may contain phosphorus. The phosphorus content, expressed as a concentration of diphosphorus pentoxide P205, will preferably be at most 15%, more preferably between 0.1 and 15% by weight and very preferably between 0.15 and 10% by weight. weight. It can also contain boron in a B / P ratio preferably between 1.05 and 2 (atomic), the sum of the contents of boron (B) and phosphorus

  (P) expressed as oxides being preferably between 5 and 15% by weight.

  The first step generally takes place at a temperature between 350 and 460 C, preferably between 360 and 450 C, a total pressure of at least 2 MPa, preferably at least 3 MPa, an hourly volume speed of between 0.1 and 5 volume of charge per volume of catalyst and per hour, preferably between 0.2 and 2 volume of charge per volume of catalyst and per hour and with a quantity of hydrogen of at least 100 normal liters per liter of charge, and preferably

  between 260 and 3000 normal liters per liter of 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 450 C. The pressure is generally at least 2MPa and preferably at least 3MPa. The amount of hydrogen is at least 100 normal liters of hydrogen per liter of charge and preferably between 200 and 3000 liters of hydrogen per liter of charge. The hourly volume speed is preferably between 0.15 and volume of charge per volume of catalyst and per hour. 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 commercial catalysts. The service life of the catalysts is

  also improved in the moderate pressure range.

  In another embodiment, the catalyst of the present invention can be used for hydrocracking under high hydrogen pressure conditions, generally 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 stage.

  The catalyst of the first stage has a hydrotreatment function and comprises a matrix preferably based on alumina, and preferably not containing a zeolite, and at least one metal having a hydrogenating function. Said matrix can also consist of, or contain, silica, silica-alumina, boron oxide, magnesia, zirconia, titanium oxide or a combination of these oxides. The hydro-dehydrogenating function is provided by at least one metal or compound of group VIII metal such as nickel and cobalt in particular. It is possible to use a combination of at least one metal or compound of group VIB metal (for example molybdenum or tungsten) and of at least one metal or compound of group VIII metal (for example cobalt or nickel) of the Periodic Table of the Elements. The total concentration of metal oxides of groups VIB and VIII is preferably between 5 and 40% by weight and more preferably between 7 and 30% by weight and the weight ratio expressed as metal oxide to metal (or metals) of the group VIB on group VIII metal (or metals) is preferably between 1.25 and 20 and more preferably between 2 and 10. In addition, this catalyst may optionally contain phosphorus. The phosphorus content, expressed as a concentration of diphosphorus pentoxide P205, will preferably be at most 15%, more preferably between 0.1 and 15% by weight and very preferably between 0.15 and 10% by weight. . It can also contain boron in a B / P ratio preferably between 1.02 and 2 (atomic), the sum of the contents of boron (B) and phosphorus (P) expressed in oxides being preferably between

5 and 15% weight.

  The first step generally takes place at a temperature between 350 and 460 C, preferably between 360 and 450 C, a pressure of at least 2MPa, preferably at least 3MPa, an hourly volume speed between 0.1 and 5 volume of feed per volume of catalyst per hour, preferably between 0.2 and 2 volume of feed per volume of catalyst per hour and with a quantity of hydrogen of at least 100 normal liters of hydrogen per liter of charge, and preferably between 260 and 3000 normal liters of hydrogen per liter of charge. For the stage of conversion with the catalyst according to the invention (or second stage), the temperatures are generally greater than or equal to 230 ° C., often between 300 ° C. and 480 ° C., and preferably between 330 ° C. and 4400 ° C. The pressure is generally greater than 5MPa and preferably greater than 7MPa. The quantity of hydrogen is at least 100 normal liters of hydrogen per liter of charge and

  preferably between 200 and 3000 liters of hydrogen per liter of charge.

  The hourly volume speed is preferably between 0.15 and 10 volume

  load per volume of catalyst and per hour.

  Under these conditions, the catalysts of the present invention exhibit a

  better conversion activity than commercial catalysts.

  The following examples illustrate the present invention without, however, limiting its scope. EXAMPLE 1 Preparation of a Support Containing a Beta Zeolite A hydrocracking catalyst support containing a beta zeolite was manufactured in large quantities so as to be able to prepare different catalysts based on the same support. For this, use is made of 18.9% by weight of a beta zeolite having an overall Si / AI ratio (measured by X-ray fluorescence) of 23.1, an atomic ratio measured by atomic adsorption of Na / AI = 0.003, a BET surface of 720 m2 / g and a pore volume of 0.298 ml of liquid nitrogen / g (at the temperature of liquid nitrogen) at P / Po = 0.14, which is mixed with 81.1% by weight of a matrix composed of ultrafine tabular boehmite or alumina gel marketed under the name SB3 by the company Condéa Chemie Gmbh. 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 humid air containing 7.5% volume of water.

  One thus obtains cylindrical extrudates of 1.2 mm in diameter, having a specific surface of 286 m2 / g, a pore volume of 0.39 cm3 / g and a size distribution of monomodal pore centered on 11 nm. Analysis of the matrix by X-ray diffraction reveals that it is composed of cubic gamma alumina of low crystallinity and beta zeolite. Example 2 Preparation of hydrocracking catalysts containing a beta zeolite (not in accordance with the invention) The support extrudates containing a beta zeolite of Example 1 are dry impregnated with an aqueous solution of a mixture of heptamolybdate. ammonium 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 NiMo4 catalyst obtained are indicated

in table 1.

  We impregnated the NiMo4 catalyst sample with an aqueous solution containing Rhodorsil EP1 silicone emulsion so as to deposit approximately 1.6% by mass of SiO2. After maturation at room temperature in an atmosphere saturated with water, the impregnated extrudates are dried overnight at C and then calcined at 550 C for 2 hours in dry air. We get a

catalyst named NiMo4Si.

  The support extrudates containing a beta zeolite from Example 1 are impregnated to dryness 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 NiMo4P catalyst is thus obtained.

  We impregnated the NiMo4P catalyst sample with an aqueous solution containing ammonium biborate and Rhodorsil EP1 silicone emulsion so as to deposit approximately 1.7% by mass of B203 and 1.5% by mass of SiO2. 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 named NiMo4PBSi is obtained.

  The final oxide contents of the NiMo4 catalysts are indicated in the

table 1.

  Table 1: Characteristics of the NiMo4 catalysts NiMo4 catalyst NiMo4 NiMo4 Si PBSi MoO3 (% wt) 14.2 13.9 13.2 NiO (% wt) 3.5 3.4 3.3 P205 (% wt) 0 0 4, 1 B203 (% wt) 0 0 1.7 SiO2 (% wt) 15.0 16.3 15.2 Supplement to 67.3 66.4 62.5% mainly composed of A1203 (% wt) Zeolite beta (% wt ) 15.5 15.3 l 14.4 Example 3: Preparation of hydrocracking catalysts containing a beta zeolite and niobium (according to the invention) The support extrudates containing a beta zeolite of Example 1 are impregnated with an aqueous solution of niobium oxalate Nb (HC204) 5, oxalic acid and ammonium oxalate. The aqueous solution containing niobium is prepared from 1330 ml of water in which 33 g of oxalic acid, 37.2 g of ammonium oxalate and 92.3 g of niobium oxalate are dissolved. To prepare the solution, the oxalic acid and ammonium oxalate mixture is first dissolved and when the solution is clear, said solution is heated to 55 ° C. and the niobium oxalate is added. It is then made up with water to obtain 1330 ml of solution. The support of example 1 above is impregnated by the so-called excess method.

  solution. The 1330 ml of solution are brought into contact with 380 g of catalyst.

  This makes it possible to deposit approximately 5% by weight of Nb on the catalyst. After two hours, the extrudates are recovered. These are then dried overnight at 120 ° C.

  a stream of dry air, and finally calcined in dry air at 550 C.

  The dried extrudates 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 contents by weight of oxides of the

  NbNiMo4 catalyst obtained are shown in Table 2.

  We impregnated the NbNiMo4 catalyst sample with an aqueous solution containing Rhodorsil EP1 silicone emulsion so as to deposit approximately 1.6% by mass of SiO2. After maturation at room temperature in an atmosphere saturated with water, the impregnated extrudates are dried overnight at C and then calcined at 550 C for 2 hours in dry air. We get a

catalyst named NbNiMo4Si.

  The support extrudates containing a beta zeolite and niobium prepared above

  above 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 catalyst

NbNiMo4P is thus obtained.

  We impregnated the NbNiMo4P catalyst sample with an aqueous solution containing ammonium biborate and Rhodorsil silicone emulsion

  EP1 so as to deposit approximately 1.7% by mass of B203 and 1.5% by mass of SiO2.

  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 named NbNiMo4PBSi is obtained.

  The final oxide contents of the NbNiMo4 catalysts are indicated in the

table 2.

  Table 2: Characteristics of the NbNiMo4 catalysts NbNiMo4 catalyst NbNiMo4 NbNiMo4 Si PBSi Nb2O5 (wt%) 4.85 4.8 4.7 MoO3 (wt%) 13.5 13.3 12.6 NiO (wt%) 3.3 3 , 2 3.1 P205 (% wt) 0 0 3.9 B203 (% wt) 0 0 1.6 SiO2 (% wt) 14.2 15.5 14.5 Complement to 64.1 63.1 59.5 % mainly composed of A1203 (% wt) Zeolite beta (% wt) 14.8 14.6 13.6 Example 4: Comparison of the hydrocracking catalysts of a partially converted vacuum diesel fuel. 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 a fixed bed, upward flow of the charge ("up-flow"). In the first reactor, 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 a group VIII element deposited on alumina. In the second reactor, the one in which the charge passes last, a hydrocracking catalyst described above is introduced. s, 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 Both catalysts undergo an in-situ sulfurization step before reaction. A

  once the sulfurization has been 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 in middle distillates (SB) and by the conversions in 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: CB =% wt of 380 minus the effluent The fraction 380 minus the effluent signifying the part of the effluent boiling at

below 380 C.

  The gross selectivity SB in middle distillates is taken equal to: SB = 100 * weight of the fraction (150 C-3800C) / weight of the fraction 380 minus the effluent The conversion to hydrodesulfurization HDS 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 Table 3 below, 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 the four catalysts.

  Table 3 Catalytic activities of the NiMo4 and NbNiMo4 catalysts in partial hydrocracking at 400 C

CB SB HDS HDN

  (% / wt) (%) (%) (%) NiMo4 50.0 65.0 98, 95 96.1 NbNiMo4Si 51.0 64.8 99.0 96.4 NiMo4PBSi 50.9 64.1 99.52 98.9 NbNiMo4PBSi 51.9 64.2 99.6 99.1 The results in Table 3 show that the presence of niobium and promoter (P, B, Si) in the catalyst containing beta zeolite brings an improvement in performance in conversion, without significant reduction in gross selectivity in

middle distillates.

  The beta zeolite catalysts of the invention containing an element of the VB group and / or phosphorus and / or boron and / or silicon making it possible to improve the performance of hydrocracking catalysts, are therefore particularly advantageous for the '' partial hydrocracking of vacuum distillate fillers

  containing nitrogen and in particular under moderate hydrogen pressure.

  EXAMPLE 5 Comparison of Hydrocracking Catalysts of High-Conversion Vacuum Diesel Fuel The catalysts whose preparations are described in the preceding examples are used under the conditions of hydrocracking with high conversion (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 final 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 VI and an element of group VIII deposited on alumina.

  0.6% by weight of aniline and 2% by weight of dimethyl- are then added to this charge.

  disulfide in order to simulate the partial pressures of HS2 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 sulphurized by an n-hexane / DMDS + aniline mixture up to 320 C. Once the sulphurization 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 rate 80 I / h Charging flow rate 80 cm3 / h Catalytic performance is expressed by the temperature which allows to reach a gross conversion level of 70% and by the gross selectivity to distillates at 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: CB =% wt of 380 m less than the effluent The gross selectivity SB in middle distillate is taken equal to SB = 100 * weight of the fraction (150 C-380 C) / weight of the fraction 380 minus the effluent The reaction temperature is fixed so as to reach a gross conversion CB equal to 70% by weight. In the following table 4, we have reported the reaction temperature and the raw selectivity for the catalysts described.

previously.

  Table 4: Catalytic activities of high-conversion hydrocracking catalysts (70%) T (c) SB (%) NiMo4 369 51.2 NbNiMo4Si 366 53.9 NiMo4PBSi 366 53, 5 NbNiMo4PBSi 364 54.1 The presence of niobium and promoter (P, B, Si) in the catalysts containing the beta zeolite makes it possible to improve the activity in conversion, which results in a reduction in the reaction temperature necessary to reach 70% of

  conversion and provides better raw selectivity for middle distillates.

  The catalysts according to the invention are therefore particularly advantageous for hydrocracking with a high charge conversion of distillate type under vacuum,

  especially at moderate hydrogen pressure.

Claims (15)

Claims   1. Catalyst comprising at least one amorphous or poorly crystallized matrix of oxide type, at least one element from the group VB, at least one zeolite beta, and at least one promoter element chosen from the group consisting of boron, phosphorus, and silicon.   2. Catalyst according to claim 1 in which the beta zeolite whose ratio   global atomic silicon / aluminum is between 10 and 200.   3. Catalyst according to one of claims 1 or 2 in which the group element VB is niobium.   4. Catalyst according to one of claims 1 to 3 further comprising at least one   element chosen from elements of group VIB and group VIII.   5. Catalyst according to claim 4, in which the element from group VIB is molybdenum or tungsten and the element from group VIII is iron, cobalt or nickel. 6. Catalyst according to one of claims 1 to 5 further comprising at least one   element chosen from the VIIA group.   7. Catalyst according to one of claims 1 to 6 containing in% by weight relative to the total mass of the catalyst:   - 0.1 to 99.8% of at least one beta zeolite.   - 0.1 to 60% of at least one element chosen from the group VB, - 0.1 to 99% of at least one porous amorphous or poorly crystallized oxide mineral matrix - from 0.1 to 20% d '' at least one promoter element chosen from the group consisting of boron, phosphorus, and silicon, not including the silicon possibly contained in the zeolite, the catalyst being able to contain in addition - from 0 to 60% of at least one element chosen from elements of group VIB and group VIII, and - from 0 to 20% of at least one element chosen from group VIIA, preferably fluorine.   8. Method for preparing a catalyst according to one of claims 1 to 7 in   which: a) a solid called the precursor is dried and weighed, containing at least the following compounds: at least one matrix, at least one beta zeolite, optionally at least one promoter element chosen from the group consisting of boron, phosphorus , and silicon, possibly at least one element chosen from elements of group VIB and group VIII, optionally at least one element of group VIIA, the whole being preferably shaped,   b) the dry solid obtained in step a) is calcined at a temperature of at least 150 C.   c) the solid precursor defined in step b) is impregnated with a solution containing at least one element of group VB, preferably niobium, d) the wet solid is allowed to stand under a humid atmosphere at a temperature between 10 and 120 C, e) the wet solid obtained in step d) is dried at a temperature between 60 and 150 C, f) the dried solid is dried in step e) in dry air at a temperature of at least less    C, preferably at least about 250 C.   9. Process for the preparation of a catalyst according to claim 8, in which at least one calcination is carried out at the end of any of the steps of the   preparation, at a temperature of at least 150 C.   10. Preparation process according to one of claims 8 or 9 wherein   proceeds to the sulfurization of the catalyst under a flow of a hydrogen / hydrogen sulfide mixture or alternatively under pure hydrogen sulfide, at a   temperature between 150 and 800 C.   11. Use of the catalyst according to one of claims 1 to 7 or prepared according to   one of claims 8 to 10 in a hydrocracking process for charges   hydrocarbons. 12. Use according to claim 11 in which the temperature is greater than C, the pressure greater than 0.1 MPa, the minimum quantity of hydrogen of liters of hydrogen per liter of charge, and the hourly volumetric speed   between 0.1 and 20 volume of feed per volume of catalyst and per hour.   13. Use according to claim 11 in a mild hydrocracking process in which the conversion level is less than 55%, the temperature is greater than 230 C, the pressure greater than 2 MPa and less than 12MPa, the amount of hydrogen at least 100 liters of hydrogen per liter of charge, and the hourly volumetric speed of between 0.15 and 10 charge volumes per volume of catalyst per hour.   14. Use according to claim 11 in a hydrocracking process, in which the conversion is greater than 55%, the temperature is greater than 230 C, the pressure greater than 5 MPa, the quantity of hydrogen at least liters of hydrogen per liter of charge, and the hourly volumetric speed between 0.15 and 10 volume of charge per volume of catalyst and per hour.   15. Use according to one of claims 11 to 14 in which a step   hydrotreating is carried out, at a temperature between 350 C and 460 C, a pressure of at least 2 MPa, with a quantity of hydrogen of at least liters of hydrogen per liter of charge, an hourly volumetric speed between 0.1 and 5 volume of feed per volume of catalyst and per hour,   and prior to the hydrocracking step.