Process for the regeneration of a zeolite-based hydrocracking catalyst and its use in a hydrocracking process.

Abstract

The present invention relates to a method for regenerating a catalyst that is at least partially spent from a hydrocracking process. The catalyst is derived from a fresh catalyst comprising at least one metal from Group VII, at least one metal from Group VIB, and a support comprising at least one zeolite. The method comprises at least one regeneration step in which the catalyst is subjected to thermal and / or hydrothermal treatment in the presence of an oxygen-containing gas at a temperature between 350°C and 460°C to obtain a regenerated catalyst. The method does not comprise any subsequent rejuvenation step involving contacting the regenerated catalyst with at least one organic or inorganic, acidic or basic compound. Figure to be published: Figure 1

Description

Title of the invention: Process for regenerating a zeolite-based hydrocracking catalyst and its use in a hydrocracking process. technical field

[0001] The invention relates to a method for regenerating a hydrocracking catalyst without a chemical modification step and to the use of the regenerated catalyst in the field of hydrocracking. The present invention also relates to the regenerated catalyst obtained by the regeneration method according to the invention. Previous technique

[0002] Hydrocracking of heavy petroleum fractions is a key refining process that allows the production, from excess and low-value heavy feedstocks, of lighter fractions such as gasoline, jet fuel, and light diesel fuels that refiners seek to adapt their production to demand. Some hydrocracking processes also yield a highly purified residue that can serve as excellent base oils or as a feedstock that can be easily utilized in a catalytic cracking unit, for example. One of the effluents particularly targeted by the hydrocracking process is the middle distillate (the fraction containing the diesel and kerosene fractions), but the gasoline produced can also be utilized, particularly to feed petrochemical intermediate production lines, depending on whether a catalytic reforming or steam cracking plant is integrated into the complex.Another advantage of hydrocracking is that the use of strong hydrogenation functions allows for the production of effluents with highly attractive qualities as fuel base. Notably, the cetane numbers of the resulting diesel fuels are among the best on the market, particularly due to the specific production conditions under which the process is implemented, resulting in a very high degree of aromatic hydrogenation. The viscosity index of the unconverted oil is also of particular interest to engine manufacturers.

[0003] Hydrocracking catalysts are generally classified on the basis of the nature of their acid function, in particular catalysts comprising an amorphous acid function of the silica-alumina type and catalysts comprising a zeolitic cracking function such as Y zeolite or beta zeolite, or even a mixture of several zeolites.

[0004] Hydrocracking catalysts are also classified according to the major product obtained when used in a hydrocracking process, the two The main products are the middle distillates and naphtha. The term "naphtha cut" or "naphtha" refers to the petroleum fraction with a lower boiling point than the middle distillates cut. The middle distillates cut typically has cutting points between 150°C and 370°C to maximize kerosene and diesel production. However, in processes specifically designed for naphtha production, for example, the lower cutting point of the middle distillates cut can be increased to boost naphtha yields. For this purpose, the naphtha cut can have boiling points ranging from that of hydrocarbon compounds with six carbon atoms per molecule (or 68°C boiling point) up to 216°C and includes the gasoline cut.Similarly, the cutting points of the middle distillates are likely to vary to increase yields as long as the product remains within the applicable specifications, which are themselves dependent on the geographical area of ​​use.

[0005] It is known to use FAU-type zeolite-based catalysts to produce the aforementioned lighter fractions, essences, or middle distillates, which are more valuable. These acidic solids are most often used in a form embedded in an aluminum matrix that acts as a binder. The catalyst, of the bifunctional type, is then obtained after impregnation and activation of a metallic phase on the previously formed support. It is generally accepted that these catalysts consist of a metal from group VIB chosen from molybdenum or tungsten and a metal from group VIII chosen from cobalt or nickel.

[0006] This type of catalyst is generally not recycled in a short loop by the refiner, and the catalyst is then sent to a landfill for separate recycling of its various components, with metals in particular being recovered by metallurgical channels. However, in certain cases, it may be advantageous to carry out one or more reprocessing steps of the catalyst in order to incorporate it into a new catalytic cycle of a hydrocracking unit. The prior art for doing so includes the following examples.

[0007] US patent 9266099 (Cosmo Oil) describes a process for regenerating hydrocracking catalysts. The hydrocracking catalyst consists of a zeolite providing the acid function and a metallic phase selected from groups VIB and VIII, which carries the hydrogenating function. The spent catalysts from the aforementioned process generally contain between 0.05 and 1 wt% carbon and are preferably composed of platinum and USY zeolite, used in the hydrocracking of Fischer-Tropsch waxes. The regeneration process is based on a preliminary step of washing the carbonaceous filler residues present in the porosity before combustion under an oxidizing atmosphere of coke at an intermediate temperature between 250 and 400°C, followed by a holding time at a second, higher temperature between 350 and 550°C. The examples in this patent show us that it would be It is preferable to regenerate at a higher temperature, i.e. 450°C (example according to the invention), rather than 430°C (comparative example) if the objective is to preserve high activity and high selectivity in hydrocracking.

[0008] French patent FR2771950 (IFPEN) describes a process for regenerating an acidic solid comprising at least one refractory oxide and / or at least one molecular sieve, which has been used for the treatment of hydrocarbon feedstocks. To this end, the spent solid is treated at a temperature between 320 and 550°C in the presence of a nitrogen oxide precursor selected from nitrate or nitrite anions, nitryl, nitrosyl or NH4+ cations, or organic compounds containing a nitro, nitroso, amino or ammonium functional group.

[0009] French patent FR2498477 (IFPEN) describes a process for regenerating an acidic solid also consisting of at least one metal chosen from groups IB, IIB or VIII. To do this, the worn solid is treated at a temperature between 300 and 600°C before being treated at a lower temperature in the presence of 0.5% to 100% water vapor, at less than 200°C.

[0010] In general, the above regeneration processes do not allow the performance of the catalyst to be recovered in the case of so-called bifunctional hydrocracking solids and therefore remain little used by manufacturers who prefer fresh catalysts.

[0011] In the case of hydrotreating catalysts, solutions have been found to circumvent this problem. The addition of an organic compound to hydrotreating catalysts—that is, without an acid function, such as zeolite or silica-alumina—is well illustrated in the literature. Their introduction improves their activity, for catalysts that have been prepared by impregnation followed by drying without subsequent calcination. These catalysts are often called "additized dried catalysts." To compensate for the hydrodesulfurizing activity deficit of the regenerated catalyst, those skilled in the art can use an additional treatment called "rejuvenation." The rejuvenation process consists of re-impregnating the regenerated catalyst with a solution containing metallic precursors, with or without organic or inorganic additives.These so-called rejuvenation processes are well known to those skilled in the art in the field of middle distillates. Numerous patents, such as US 7,906,447, US 8,722,558, US 7,956,000, US 7,820,579, FR 2,972,648, US2017 / 036202, and CN102463127, propose various methods for rejuvenating middle distillate hydrotreating catalysts.

[0012] US patent 7,956,000, in particular, describes a rejuvenation process involving contact between a catalyst comprising a metal oxide of group VIB and a metal oxide of group VIII with an acid and an organic additive having a boiling point between 80 and 500°C and a water solubility of at least 5 grams per liter (20°C, atmospheric pressure), possibly followed by drying under conditions such that at least 50% of the additive is retained in the catalyst. The hydrotreating catalyst may be a fresh hydrotreating catalyst or a used hydrotreating catalyst that has been regenerated.

[0013] US patent 2014076780 describes a method for obtaining a catalyst comprising an amorphous alumina-based support, a Cl-C4 dialkyl succinate, citric acid and optionally acetic acid, phosphorus, and a hydro-dehydrogenating function comprising at least one element from Group VIII and at least one element from Group VIB. The process for preparing said catalyst includes impregnating a catalytic precursor, which may be in a dried, calcined, or regenerated state, with an impregnation solution comprising at least one C1-C4 dialkyl succinate and citric acid. The patent indicates that this rejuvenation treatment makes it possible, in particular, to eliminate the crystalline phases refractory to sulfidation that are generated during high-temperature heat treatments.

[0014] Far fewer documents describe rejuvenation processes such as those proposed for the hydrotreating catalysts mentioned above, undoubtedly due to the complexity of implementation on bifunctional catalysts for which both the hydrogenating and acid functions must be restored simultaneously. A few documents are nevertheless included below.

[0015] US patent 5206194 (Union Oil Company) describes a process for rejuvenating hydrocracking catalysts consisting of an acidic function selected from a wide list of zeolites, including USY CBV720, CBV712, or LZ-210, and a hydrogenating function provided by a Group VIII metal selected from platinum or palladium. The spent catalyst consists of 2 to 20% carbon and is regenerated before being reactivated. The catalyst, regenerated between 510°C and 680°C, contains less than 1% by weight of carbon and is rejuvenated with a solution of ammonium salts, preferably ammonium nitrate, carbonate, or bicarbonate. The resulting hydrocracking catalyst is used under conditions such that the equivalent nitrogen content is less than 200 ppm.The examples in the document clearly demonstrate that a relatively high optimal regeneration temperature, between 540 and 590°C (1000 and 1100°F respectively), is necessary to maximize conversion activity, whether implemented in the first or second hydrocracking stage. However, in neither case does this temperature achieve activity comparable to that of a fresh catalyst. The rejuvenation stage improves performance, but as with regeneration alone, the findings suggest targeting a high regeneration temperature.

[0016] US patent application 20130137913 (SHELL) describes a process for rejuvenating a zeolite catalyst preferably used for the transformation of oxygenated compounds into olefins of at least four carbon atoms. The acid function of the catalysts is provided by a 10MR zeolite. The rejuvenation treatment consists of treating the catalyst with an acidic solution consisting of acetic, oxalic, or tartaric acid, or alternatively with an acidified ammonia solution consisting of various inorganic or organic acids selected from HCl, HBr, HI, nitric acid, sulfuric acid, or para-toluene sulfonic acid. Moreover, the spent catalyst can be pre-heat treated in an oxidizing environment with, at choice, O2, O3, SO3, N2O, NO, NO2, N2O5 at a temperature between 550 and 750°C, but the treatment can also take place before the rejuvenation step with the organic acid.The examples in this document teach us that a single regeneration leads to a very sharp drop in activity and that rejuvenation improves performance, but does not allow conversions to be achieved equivalent to those of a fresh catalyst.

[0017] US patent application 2018318822 (EXXON MOBIL) describes a process for regenerating and rejuvenating a spent catalyst. The spent catalyst is bifunctional, consisting of a zeolite or a mixture of several zeolites and a metallic phase composed of a metal from Group VIB and a metal from Group VIII. This patent application targets use in catalytic dewaxing. The spent catalyst is first regenerated under air at a temperature between 370 and 710°C to remove the coke and obtain a calcined catalyst, which is then contacted with a solution containing a complexing agent, with a molar ratio of complexing agent to metals of 1.25 to 10. Finally, the rejuvenated catalyst is simply dried at low temperature. Citric acid is preferred, and glycol can also be used as the complexing agent; optionally, both can be used in a mixture.Once again, regardless of the catalyst functions illustrated in the examples – HDS, HDN, cloud point improvement – ​​which are linked to the isomerizing activity of the catalyst, the performance of the regenerated catalyst at 540°C is lower than that of the fresh catalyst, and regeneration leads to an improvement, but one that remains insufficient to return to the performance of the fresh catalyst.

[0018] It then appears that no sufficiently attractive technical solution exists for the regeneration or rejuvenation of a bifunctional hydrocracking catalyst consisting of a metallic phase based on Group VIB and Group VIII metals and an acidic phase consisting of at least one zeolite. Examples in the literature generally report insufficient catalytic activity or yield. Furthermore, no information is provided on performance in hydrogenation of regenerated catalysts which would be obtained, but on the basis of the lessons learned in the field of hydrotreating catalysts, it seems evident that a strong degradation of product qualities such as the cetane number of diesel fuel should be suffered if the hydrocracking catalyst is not rejuvenated after a regeneration step alone.

[0019] The objective of the present invention is therefore to provide a regeneration process that at least maintains, or even improves, the conversion activities and / or hydrogenating properties of Group VIII and Group VIB metal-based hydrocracking catalysts, as well as those of a zeolite, compared to the corresponding fresh catalyst. These catalysts have been previously deactivated during an operating cycle in hydrocracking reactions. In particular, the invention relates to the treatment of spent catalysts in hydrocracking processes of hydrocarbon feedstocks of any origin (fossil and / or vegetable and / or animal and / or plastic-derived) containing at least 2% coke by weight and whose activity loss is at least 7°C compared to the fresh catalyst, to a target conversion level defined beforehand by the refiner (and typically between 60% and 90% conversion of the hydrocarbon feedstock to be treated).

[0020] The applicant has indeed found that, surprisingly, contrary to the recurring teachings of the prior art, the implementation of a regeneration process of a spent hydrocracking catalyst comprising at least one metal from group VIII, at least one metal from group VIB and at least one acid function, at a sufficiently low temperature, i.e. below 460°C, makes it possible to obtain a hydrocracking catalyst with improved catalytic performance compared to catalysts regenerated at higher temperatures and this without having to resort to a rejuvenation treatment. Summary of the invention

[0021] The invention relates to a process for regenerating a catalyst that is at least partially spent from a hydrocracking process, said catalyst that is at least partially spent being from a fresh catalyst comprising at least one metal from group VIII, at least one metal from group VIB, and a support comprising at least one zeolite, said process includes at least one regeneration step in which the catalyst that is at least partially spent is subjected to a thermal and / or hydrothermal treatment in the presence of a gas containing oxygen at a temperature between 350°C and 460°C so as to obtain a regenerated catalyst, said process not including a subsequent rejuvenation step of contacting said regenerated catalyst with at least one organic or inorganic, acidic or basic compound.

[0022] An advantage of the invention is to provide a regeneration process operating at low temperature allowing to obtain a regenerated hydrocracking catalyst with improved catalytic performance compared to prior art catalysts, regenerated at higher temperatures, and this without having to resort to a rejuvenation treatment.

[0023] Another advantage of the invention is to provide a process for regenerating a hydrocracking catalyst which at least maintains, with respect to the corresponding fresh catalyst, the converting activities and / or hydrogenating properties of said catalyst.

[0024] Here, "maintaining activity" refers to a temperature differential applied to achieve a target conversion of a hydrocarbon feedstock, typically a vacuum distillate, that is minimal or even zero compared to the fresh catalyst and maximal compared to the spent catalyst. "Maintaining HDN, HDA, and indirectly cetane number performance" also refers to having a regenerated catalyst that exhibits performance as close as possible to that of the fresh catalyst, and therefore the best possible performance compared to the spent catalyst.

[0025] Without being linked to any theory, it appears that unlike hydrotreating catalysts composed solely of amorphous oxides without a zeolitic acid function in their support, hydrocracking catalysts form relatively little crystalline phase refractory to sulfidation such as NiMoO4 at low regeneration temperatures, which makes it possible to avoid having to resort to an additional rejuvenation treatment step with a chemical compound of any nature and thus simplifies the reprocessing of the spent catalyst.

[0026] Another advantage of the present invention is therefore to provide an economically attractive and environmentally sustainable regeneration process for industrial users. This result appears to be specific to hydrocracking catalysts prepared from non-noble metals such as nickel, cobalt, molybdenum, or tungsten.

[0027] The present invention also relates to the use of the regenerated catalyst prepared according to the process of the invention in a process of hydrocracking hydrocarbon cuts.

[0028] The present invention also relates to the regenerated catalyst obtained by the regeneration process according to the invention.

[0029] Characterization techniques

[0030] In the following, the groups of chemical elements are given according to the CAS classification (CRC Handbook of Chemistry and Physics, publisher CRC press, editor-in-chief DR Lide, 81st edition, 2000-2001). For example, group VIII according to the CAS classification corresponds to the metals of columns 8, 9 and 10 according to the new IUP AC classification.

[0031] The different atomic contents in the zeolites, alumina precursors, supports or catalysts are measured by X-ray fluorescence, by atomic absorption spectrometry, by inductively coupled plasma spectrometry (ICP) or by combustion, using the method most suitable for the value measured.

[0032] The contents of Group VIB metals, Group VIII metals, and possibly phosphorus in the fresh catalyst, in the at least partially spent catalyst, or in the regenerated catalyst are expressed as oxides after correction for the loss on ignition of the catalyst sample. This correction allows for comparison of the metal contents of fresh, at least partially spent, and regenerated catalysts. The loss on ignition of the catalyst corresponds to the sum of its water, carbon, sulfur, nitrogen, and / or any other contaminant contents that are removed by the heat treatment applied to measure this loss on ignition. This is measured after heat treatment in a muffle furnace at 550°C for 1.5 hours.

[0033] Unlike metal contents, carbon or sulfur contents in the at least partially worn catalyst or in the regenerated catalyst are expressed in relation to the total weight of the catalyst in question, without correction for loss on ignition.

[0034] The crystal parameter aO of the unit cell of the zeolite, or lattice parameter, is measured by X-ray diffraction (XRD) according to ASTM 03942-80. X-ray diffraction is performed with a PANalytical X'Pert Pro diffractometer operating in reflection and equipped with a back monochromator using CuKalpha radiation (XKai = 1.5406 Å, XKa2 = 1.5444 Å).

[0035] According to the ICDD database, PDF datasheet 00-012-0348, the NiMoO4 crystalline phase exhibits several diffraction lines, the most intense line being located at d = 3.35 Å. The interplanar spacing d and the angular position q are related by the Bragg equation (with n the diffraction order = 1 and λ the X-ray wavelength (1.5406 Å)): 2d sin(q) = n 1

[0036] In this description, the "specific surface area" or "BET surface area" of zeolites, supports, or catalysts refers to the BET specific surface area determined by nitrogen adsorption in accordance with ASTM D 3663-78, established from the BRUNAUER-EMMETT-TELLER method described in "The Journal of the American Society", 60, 309, (1938). Four pressure points are used, P / P0 = 0.050, 0.075, 0.100, and 0.125. Prior to measuring the nitrogen adsorption-desorption isotherm, the sample is pretreated at 450°C for 4 hours under secondary vacuum (10⁴ Pa).

[0037] The pore distribution measured by nitrogen adsorption was determined by the Barrett-Joyner-Halenda (BJH) model. The nitrogen adsorption-desorption isotherm according to the BJH model is described in the periodical "The Journal of the American Society", 73, 373 (1951) written by EPBarrett, LGJoyner and PPHalenda. The "total pore volume" of zeolites, supports or catalysts is understood to be the volume measured by nitrogen adsorption for P / PO = 0.99, the pressure at which it is assumed that nitrogen has filled all the pores.

[0038] The "mesoporous volume" of zeolites is understood to be the difference between the total pore volume described above and the micropore volume. The micropore volume is also determined from the nitrogen adsorption-desorption isotherm, using the "t" method (Lippens-De Boer method, 1965), which corresponds to a transform of the nitrogen adsorption isotherm as described in "Adsorption by powders and porous solids. Principles, methodology and applications" by F. Rouquérol, J. Rouquérol and K. Sing, Academie Press, 1999. Eight pressure points are used: P / PO = 0.075, 0.100, 0.125, 0.150, 0.175, 0.200, 0.250 and 0.300.

[0039] In the following text, the expressions "between ... and ..." and "between ... and ..." are equivalent and mean that the limit values ​​of the interval are included in the range of values ​​described. If this were not the case and the limit values ​​were not included in the range described, such clarification will be provided by the present invention.

[0040] In the sense of the present invention, the different parameter ranges for a given step, such as pressure ranges and temperature ranges, can be used alone or in combination. For example, in the sense of the present invention, a preferred range of pressure values ​​can be combined with a more preferred range of temperature values.

[0041] The term “hydrotreating” means reactions including hydrodesulfurization (HDS), hydrodeazotation (HDN) and hydrogenation of aromatics (HDA).

[0042] Hydrocracking, on the other hand, consists of all reactions that involve a reduction in the boiling point of the compounds present in the feedstock. In other words, it involves converting compounds with a boiling point above a target temperature into products with a boiling point below that same temperature. The choice of temperature depends on the process and the feedstocks. For a process aimed at maximizing gasoline yield, conversion is most often defined as occurring at a temperature close to 150 to 200°C, whereas for a process aimed at maximizing middle distillates (diesel and kerosene), conversion is defined as occurring at a temperature between approximately 350 and 385°C.

[0043] The term "fraction X+" refers to all compounds having a boiling point above temperature X. The term "net conversion of fraction X+" refers to the difference between the yield of the section (or fraction) with a boiling point below temperature X and the yield of the section with a boiling point below the temperature X present in the test load referred to the yield in the boiling point section higher than the temperature X in the load, all the above yields being mass-based. Description of the invention

[0044] According to the invention, the invention relates to a process for regenerating a catalyst that is at least partially spent from a hydrocracking process, said catalyst that is at least partially spent being from a fresh catalyst comprising at least one metal from group VIII, at least one metal from group VIB, and a support comprising at least one zeolite, said process includes at least one regeneration step in which the catalyst that is at least partially spent is subjected to a thermal and / or hydrothermal treatment in the presence of a gas containing oxygen at a temperature between 350°C and 460°C so as to obtain a regenerated catalyst, said process not including an additional rejuvenation step of contacting said regenerated catalyst with at least one organic or inorganic, acidic or basic compound.

[0045] The regenerated catalyst obtained by the process according to the invention is derived from a catalyst that is at least partially used, itself derived from a fresh catalyst, used in a hydrocracking process of hydrocarbon cuts for a certain period of time and which has an activity significantly lower than the fresh catalyst, thus requiring its replacement.

[0046] A "at least partially spent catalyst" is defined as a catalyst discharged from a hydrocracking process carried out under the conditions described below and which has not undergone heat treatment under a gas containing air or oxygen at a temperature above 250°C (often also called a regeneration step). It may have undergone oil removal or a washing step.

[0047] Preferably, "at least partially spent catalyst" means a catalyst used in a vacuum hydrocracking process of distillates having at least 2% by weight of coke and whose loss of activity is at least 7°C, preferably between 7°C and 60°C, and even more preferably between 10°C and 40°C, compared to the fresh catalyst, to a target conversion level defined beforehand by the refiner (and typically between 60% and 90% conversion of the hydrocarbon feed to be treated).

[0048] Target performance

[0049] The performance of the regenerated hydrocracking catalyst obtained according to the invention can be compared based on the conversion activity relative to a defined cutting point. For example, at a given temperature and operating conditions, the fraction of the hydrocarbon feedstock with a boiling point above a given temperature, 370°C for so-called maxi-distillate processes, can be evaluated. averages, or 175°C for so-called maxi-naphtha processes, which is converted. Another way to evaluate the catalyst is to look at the yield of hydrocarbon fractions of interest under given conditions or for a given conversion, the latter being defined as above. The fractions for which the yield is to be maximized can be heavy gasoline, kerosene, or diesel, depending on the cut points desired by the refiner. Finally, a last criterion for evaluating the catalyst regenerated according to the process of the invention is its ability to perform hydrodeazotation of the hydrocarbon fraction, i.e., a percentage of organic nitrogen removal, or its ability to hydrogenate aromatic compounds, or its ability to obtain gasoline, kerosene, diesel, or unconverted oil fractions with desirable qualities, these being any that the refiner seeks to maximize in its operation.Examples include the cetane number of diesel fuel and the viscosity index of unconverted oil, but other product properties can also be recovered by applying the process that is the subject of the invention.

[0050] Fresh catalyst

[0051] The fresh catalyst used in a hydrocarbon fraction hydrocracking process is known to those skilled in the art. It comprises at least one metal from group VIII, at least one metal from group VIB, and a support comprising at least one zeolite as described below.

[0052] The group VIB metal present in the active phase of the fresh catalyst is preferably chosen from molybdenum and tungsten. The group VIII metal present in the active phase of the fresh catalyst is preferably chosen from cobalt, nickel, and mixtures of these two elements. The active phase of the fresh catalyst is preferably chosen from the group formed by the combination of nickel-molybdenum, cobalt-molybdenum, nickel-tungsten, nickel-molybdenum-tungsten, and nickel-cobalt-molybdenum, and most preferably the active phase consists of nickel and molybdenum, nickel and tungsten, or a nickel-molybdenum-tungsten combination.

[0053] The content of group VIII metal in the fresh catalyst is less than 20% by weight, preferably between 0.03 and 15% by weight, most preferably between 0.5 and 10% by weight, and even more preferably between 1 and 8% by weight expressed as group VIII metal oxide relative to the total weight of the fresh catalyst.

[0054] The content of metal of group VIB in the fresh catalyst is between 1 and 50% by weight, preferably between 5 and 40% by weight, and more preferably between 10 and 35% by weight expressed as metal oxide of group VIB relative to the total weight of the fresh catalyst.

[0055] The molar ratio of group VIII metal to group VIB metal of the fresh catalyst is generally less than 1, preferably between 0.01 and 0.75, and most preferably between 0.10 and 0.60.

[0056] Optionally, the fresh catalyst may also have a phosphorus content generally less than 15% by weight, preferably between 0.1 and 10% by weight, most preferably between 0.1 and 8% by weight, and even more preferably between 0.2 and 6% by weight of P2O5 relative to the total weight of fresh catalyst.

[0057] Furthermore, in the case where the fresh catalyst includes phosphorus, the phosphorus / (metal of group VIB) molar ratio is generally between 0.02 and 1, preferably between 0.04 and 0.8, and most preferably between 0.1 and 0.75.

[0058] According to the invention, the support comprises at least one zeolite. Said zeolite is preferably chosen from among the zeolites belonging to the FAU group (including zeolites X, Y, USY and any other designation of Y zeolites which have undergone a desalumination treatment), BEA, ISV, IWR, IWW, MEI, UWY, MEL, MTW, MTT, MRE, FER or MFI and preferably, the zeolite is chosen from 10MR or 12MR zeolites or even more preferably from the zeolites of the FAU or BEA groups. Some examples of zeolites from the preceding families, without restricting the list of possible choices, are cited below: ZSM-5 (MFI), ZSM-11 (MEL), ZSM-12 (MTW), ZSM-23 (MTT), ZSM-35 (FER), ZSM-48 (MRE), CP841E, CP814C, CP811C-300, HSZB25, HSZB30, HSZB150, HSZ931, HSZ940, HSZ980 (BEA), or Y82, Y84, CP300-56, CBV712, CBV720, CBV760, CBV780, CBV500, HSZ320, HSZ330, HSZ331, HSZ385, HSZ350, HSZ360, HSZ390, HSZ341, or HSZ371 (FAU, or USY).

[0059] Preferably, the support comprises USY zeolite and / or Beta zeolite, alone or in mixture, and preferably comprises and is made up of USY zeolite. All methods of zeolite preparation can be applied to obtaining the zeolites used in the preparation of the fresh catalyst.

[0060] The weight content of zeolite in said support is between 1 and 80% by weight, preferably between 2 and 70% by weight and most preferably between 3 and 60% by weight in relation to the total weight of said support.

[0061] When the support comprises a mixture of USY zeolite and Beta zeolite, the weight ratio of USY to Beta is between 1 and 20, preferably between 1.5 and 18 and even more preferably between 2 and 15.

[0062] Preferably, when the support comprises a USY zeolite, the latter has a lattice parameter between 24.10 and 24.70 Å, preferably between 24.15 and 24.60 Â, more preferably between 24.20 and 24.56 Â, a Si / Al molar ratio between 2 and 300, more preferably between 2.5 and 150, more preferably between 2.5 and 100, a BET surface area greater than 500 m2 / g, more preferably between 600 and 1100 m2 / g, more preferably between 750 and 1000 m2 / g, a mesoporous volume between 0.05 and 0.9 mL / g, more preferably between 0.08 and 0.7 mL / g and more preferably between 0.1 and 0.6 mL / g.

[0063] Preferably, when the support contains a Beta zeolite, the latter has a Si / Al molar ratio of between 5 and 300, preferably between 6 and 200, even more preferably between 6 and 100, a BET surface area greater than 500 m2 / g, preferably between 550 and 900 m2 / g, even more preferably between 550 and 800 m2 / g, a mesoporous volume of between 0.05 and 0.9 mL / g, preferably between 0.1 and 0.9 mL / g and even more preferably between 0.15 and 0.85 mL / g.

[0064] The support may also advantageously comprise at least one oxide binder and preferably a porous solid selected from the group consisting of aluminas, silicas, silica-aluminas, or oxides of titanium, boron, zirconia, or magnesium used alone or in mixture with alumina or silica-alumina. Preferably, the binder is based on alumina, silica, or silica-alumina.

[0065] When the oxide binder is alumina-based, it contains more than 50% alumina by weight relative to the total weight of the support and, generally, it contains only alumina or silica-alumina as defined below.

[0066] Preferably, the oxide binder comprises alumina. The alumina may advantageously be in any form known to those skilled in the art. Preferably, the alumina is selected from the group consisting of alpha, rho, chi, kappa, eta, and gamma aluminas. Most preferably, the alumina is gamma alumina.

[0067] In another embodiment, the oxide binder is a silica-alumina containing at least 50% by weight of alumina relative to the total weight of said oxide binder. The silica content in the binder is less than 50% by weight relative to the total weight of the support, most often less than 45% by weight, preferably less than 40% by weight.

[0068] When the binder of said catalyst is silica-based, it contains more than 50% silica by weight relative to the total weight of the binder and, generally, it contains only silica.

[0069] Preferably, the support comprising at least one zeolite advantageously has a total pore volume between 0.15 and 1.2 cm3.g*, preferably between 0.18 and 1.1 cm3.g', and most preferably between 0.2 and 1.0 cm3.g*.

[0070] The BET surface area of ​​the support comprising at least one zeolite is advantageously greater than 150 m².g*, preferably between 150 and 900 m².g*, in a very preferred between 180 and 850 m2.g ', and even more preferred between 200 and 800 m2^1.

[0071] The support is advantageously in the form of irregular and non-spherical beads, extrudates, pellets or agglomerates whose specific shape may result from a crushing step.

[0072] The fresh catalyst may also further comprise at least one organic compound containing oxygen and / or nitrogen and / or sulfur before sulfidation. Such additives are known to those skilled in the art. Generally, the organic compound is chosen from among compounds having one or more chemical functions selected from among a carboxyl group, alcohol, thiol, thioether, sulfone, sulfoxide, ether, aldehyde, ketone, ester, carbonate, amine, nitrile, imide, oxime, urea and amide, or compounds including a furan ring, or sugars.

[0073] The content of organic compound(s) containing oxygen and / or nitrogen and / or sulfur on the fresh catalyst is between 1 and 30% by weight, preferably between 1.5 and 25% by weight, and more preferably between 2 and 20% by weight relative to the total weight of the fresh catalyst.

[0074] The preparation of the fresh catalyst is known to those skilled in the art and generally comprises an impregnation step of Group VIII and Group VIB metals, and optionally phosphorus and / or the organic compound, onto the support comprising at least one zeolite, followed by drying, and then optional calcination to obtain the metals in their oxide forms. Before its use in a hydrocarbon fraction hydrocracking process, the fresh catalyst is generally subjected to sulfidation to obtain the metals in their sulfided or partially sulfided forms as described below.

[0075] According to a variant of the invention, when an organic compound is present, the fresh catalyst has not undergone calcination during its preparation, i.e. the impregnated catalytic precursor has not been subjected to a heat treatment step at a temperature above 200°C under an inert atmosphere or under an atmosphere containing oxygen, in the presence of water or not.

[0076] According to another embodiment of the invention, the fresh catalyst underwent a calcination step during its preparation, i.e. the impregnated catalytic precursor was subjected to a heat treatment step at a temperature between 200 and 1000°C and preferably between 250 and 750°C, for a period typically between 15 minutes and 10 hours, under an inert atmosphere or under an atmosphere containing oxygen, in the presence of water or not.

[0077] Worn catalyst

[0078] During the process of hydrocracking hydrocarbon cuts, coke, sulfur and nitrogen as well as possibly other contaminants from the feed such as silicon, arsenic and metals form and / or are deposited on the catalyst and transform the fresh catalyst into a catalyst that is at least partially used.

[0079] A “at least partially spent catalyst” is defined as a catalyst discharged from a hydrocracking process carried out under the conditions described below and which has not undergone heat treatment under a gas containing air or oxygen at a temperature above 250°C (often also called a regeneration step). It may have undergone a deoiling or washing step.

[0080] Preferably, "at least partially spent catalyst" means a catalyst used in a vacuum hydrocracking process of distillates having at least 2% by weight of coke and whose loss of activity is at least 7°C, preferably between 7°C and 60°C, even more preferably between 10°C and 40°C, compared to the fresh catalyst, to a target conversion level defined beforehand by the refiner (and typically between 60% and 90% conversion of the hydrocarbon feed to be treated).

[0081] The at least partially worn catalyst is composed of a support comprising at least one zeolite and a hydrogenating phase formed of at least one metal from group VIB, at least one metal from group VIII, as well as carbon, sulfur, nitrogen and optionally other contaminants from the feed such as arsenic and metals.

[0082] The contents of metals of group VIB and group VIII and optionally of phosphorus in the at least partially spent catalyst are substantially identical to the contents in the fresh catalyst from which it is derived.

[0083] By "substantially identical" means that each of the metallic elements mentioned is present in the same proportions as in the initial fresh catalyst to within 5% relative.

[0084] It should be noted that the term "coke" or "carbon" in this application refers to a hydrocarbon-based substance deposited on the surface of the catalyst at least partially worn during its use, this substance having a highly cyclized and condensed structure.

[0085] The at least partially worn catalyst contains in particular carbon at a content generally greater than 2% by weight, preferably between 2.5% and 40% by weight, most preferably between 3% and 30% by weight, and even more preferably between 3.5% and 25% by weight in relation to the total weight of the at least partially worn catalyst.

[0086] Regeneration

[0087] The regeneration process according to the invention for the at least partially spent catalyst includes a step of removing, at least partially, the coke, sulfur, and nitrogen at a relatively low temperature. According to the invention, the at least partially spent catalyst is subjected to thermal and / or hydrothermal treatment in the presence of an oxygen-containing gas at a temperature between 350°C and 460°C so as to obtain a regenerated catalyst.

[0088] Although possible, regeneration is preferably not carried out by keeping the loaded catalyst in the hydrocracking reactor (in-situ regeneration). Preferably, the at least partially spent catalyst is therefore extracted from the reactor and processed in a regeneration facility in order to carry out regeneration in said facility (ex-situ regeneration).

[0089] The regeneration step is preferably preceded by a de-oiling step. The de-oiling step preferably comprises contacting the at least partially spent catalyst with a stream of inert gas (i.e., essentially oxygen-free), preferably in a nitrogen or similar atmosphere, at a temperature between 200°C and 400°C, preferably between 250°C and 350°C. The inert gas flow rate, expressed as a flow rate per unit volume of the catalyst, is between 5 and 150 L / h. The de-oiling step preferably lasts between 3 and 7 hours. It can advantageously be carried out in the hydrocracking unit, but can also be carried out ex-situ, like the regeneration step itself.

[0090] In one embodiment, the oil removal step can be carried out by light hydrocarbons, by steam treatment or any other similar process.

[0091] In a preferred mode, the oil removal step is replaced by a washing step with a lighter hydrocarbon feedstock than that used in the hydrocracking process, for example, diesel fuel or a liquid solvent at room temperature, preferably an aromatic compound such as toluene or xylene. The washing is carried out at a temperature below 250°C and can be performed continuously in a flow-through bed or reflux configuration.

[0092] The oil removal step makes it possible to eliminate soluble hydrocarbons which could prove dangerous in the regeneration step, because they present risks of flammability under an oxidizing atmosphere.

[0093] According to the invention, the regeneration step consists of a thermal and / or hydrothermal treatment in the presence of an oxygen-containing gas, according to any technique known to those skilled in the art. This treatment can be carried out, for example, in a flow bed, a lick bed, or in a static atmosphere. For example, the furnace used can be a rotary kiln, a vertical radial flow bed kiln, or a belt kiln.

[0094] According to the invention, the regeneration of the at least partially worn catalyst is carried out at a temperature between 350°C and 460°C, preferably between 360 and 450°C, more preferably between 370 and 430°C, and even more preferably between 380 and 420°C. The regeneration time is preferably greater than 1 hour, more preferably between 1 and 100 hours, more preferably between 1.5 and 25 hours, and particularly preferably between 2 and 10 hours. The oxygen content of said gas is less than that of air (20% v / v), preferably between 2 and 20% v / v, more preferably between 5 and 20% v / v, and even more preferably the gas used is air alone.

[0095] The water content of said gas is advantageously between 0 and 1000 g of water per kg of dry air, preferably between 0 and 500 g of water per kg of dry air, preferably between 0 and 250 g of water per kg of dry air, and even more preferably between 0 and 100 g of water per kg of dry air.

[0096] Preferably, the regeneration step is carried out in a gas stream containing oxygen. The gas flow rate in terms of flow rate per unit volume of the at least partially spent catalyst is preferably between 20 and 2000 NL.L '.h ', more preferably between 30 and 1000 NL.L '.h1, and particularly preferably between 40 and 500 NL.L '.h1.

[0097] In a variant of the regeneration process, one or more temperature steps are carried out at temperatures lower than the maximum temperatures of the regeneration step.

[0098] In a preferred embodiment, the oxygen content of said gas is progressively increased from a content between 2 and 10% v / v to a maximum content less than or equal to 20% v / v during at least one of the regeneration stages carried out in a single step or by including stages with intermediate oxygen proportions, preferably the oxygen content is progressively increased during the last regeneration stage carried out between 350 and 460°C.

[0099] In the case where the at least partially worn catalyst is subjected to hydrothermal treatment, this can be carried out instead of or in combination with a steam-free heat treatment.

[0100] According to the invention, said process does not include a subsequent rejuvenation step of contacting said regenerated catalyst with at least one organic or inorganic, acidic or basic compound, said organic compound preferably being chosen from complexing and / or chelating and / or polar organic compounds.

[0101] The regenerated catalyst comprises a metallic phase formed of at least one metal from group VIB and at least one metal from group VIII and a support comprising at less a zeolite. Following regeneration, the hydrogenating function comprising the metals of group VIB and group VIII of the regenerated catalyst is in a partially oxidized form. Advantageously, it contains less NiMoO4 (based on the area of ​​the diffraction line located at the interplanar spacing d = 3.35 Å) than if the catalyst had been regenerated at a higher temperature, i.e., at a temperature strictly above 460°C. Preferably, the catalyst contains no, or only traces of, crystalline phases such as NiMoO4.

[0102] The contents of Group VIB and Group VIII metals, and optionally phosphorus, in the regenerated catalyst are substantially identical to the contents of the at least partially spent catalyst and the contents of the fresh catalyst from which it is derived. To this end, the contents are expressed relative to the weight of the catalyst after correction for loss on ignition (as described in the section "Characterization Techniques"). Again, "substantially identical" means that each of the aforementioned metallic elements is present in the same proportions, within 5% relative, as in the at least partially spent catalyst or the fresh catalyst from which it is derived.

[0103] The regenerated catalyst is characterized by a BET surface area greater than 80%, preferably greater than 85% and most preferably greater than 90% of that of the corresponding fresh catalyst.

[0104] The total pore volume of the regenerated catalyst is generally greater than 80%, preferably greater than 85% and most preferably greater than 90% of that of the corresponding fresh catalyst.

[0105] The regenerated catalyst obtained in the regeneration step contains residual carbon at a level of less than 2% by weight, preferably less than 1.5% by weight, most preferably less than 1% by weight, and most preferably between 0.01 and 0.8% by weight relative to the total weight of the regenerated catalyst. The regenerated catalyst may also contain no residual carbon.

[0106] The regenerated catalyst may contain residual sulfur at a level of less than 3% by weight, preferably less than 2% by weight, preferably between 0.01% and 1.5% by weight, and even more preferably between 0.1% and 1.2% by weight relative to the total weight of the regenerated catalyst. The regenerated catalyst may also contain no residual sulfur.

[0107] Optionally, the regenerated catalyst may also have a low content of contaminants from the feed treated by the fresh catalyst from which it is derived, such as arsenic, mercury, and metals such as nickel, vanadium, iron, calcium, sodium.

[0108] Preferably, the arsenic or mercury content is less than 2000 ppm by weight and most preferably less than 1000 ppm by weight relative to the total weight of the regenerated catalyst.

[0109] Preferably, the content for each metal that would not be present in the initial formulation of the fresh catalyst is less than 1% by weight and most preferably less than 5000 ppm by weight relative to the total weight of the regenerated catalyst.

[0110] Another object of the invention relates to the catalyst obtained by the regeneration process according to the invention. [YES] Sulfurization (optional step)

[0112] Before its use in a hydrocracking process, it is advantageous to transform the regenerated catalyst obtained according to the process of the invention into a sulfide catalyst in order to obtain the metals in their sulfide or partially sulfide forms. This activation or sulfidation step is carried out by methods well known to those skilled in the art, and advantageously under a sulfur-reducing atmosphere in the presence of hydrogen and hydrogen sulfide.

[0113] Said regenerated catalyst is advantageously sulfided ex situ or in situ. The sulfiding agents are H2S gas, elemental sulfur, CS2, mercaptans, sulfides and / or polysulfides, hydrocarbon cuts with a boiling point below 400°C containing sulfur compounds, or any other sulfur-containing compound used for activating hydrocarbon feedstocks for the purpose of sulfiding the catalyst. Said sulfur-containing compounds are advantageously selected from alkyl disulfides such as, for example, dimethyl disulfide (DMDS), alkyl sulfides such as, for example, dimethyl sulfide, thiols such as, for example, n-butylmercaptan (or 1-butanethiol), and polysulfide compounds of the tertiononyl polysulfide type. The catalyst can also be sulfided with the sulfur contained in the feedstock to be desulfurized. Preferably, the catalyst is sulfided in situ in the presence of a sulfurizing agent and a hydrocarbon feedstock.Preferably, the catalyst is sulfided in situ in the presence of a hydrocarbon feedstock with added dimethyl disulfide.

[0114] Hydrocracking process

[0115] Finally, another object of the invention is the use of the regenerated catalyst according to the process of the invention in hydrocracking processes of hydrocarbon fractions.

[0116] The hydrocracking process for hydrocarbon fractions can be carried out in one or more fixed-bed reactors in series with recycling in the various hydrotreating or hydrocracking sections that compose it. These schemes are well known to refiners and can be modified according to the requirements for selectivity, activity, and yields. Examples include two-stage processes with recycling in the second reactor, one-stage processes without recycling, and processes in A step involving recycling to the hydrotreating reactor or even recycling to the hydrocracking reactor. All variants known to those skilled in the art can be applied to the use of the catalyst according to the invention. In other words, if the refiner incorporates other steps such as, for example, hydrotreating upstream or downstream of hydrocracking, this remains within the scope of application envisaged by the invention.

[0117] The hydrocarbon fraction hydrocracking process is carried out in the presence of a regenerated catalyst according to the process of the invention in at least one of the reactors comprising it. It can also be carried out in the presence of a mixture of a regenerated catalyst and a fresh catalyst or of any other origin.

[0118] The metallic phase, the acid phase, and the support of the fresh catalyst may or may not be identical to those present in the regenerated catalyst. In particular, if the performance of the regenerated catalyst is not entirely identical to that of the corresponding fresh catalyst, the refiner may decide to chain one or more other fresh catalysts exhibiting different catalytic performances so that the chain meets the process requirements. The catalytic performances thus adjusted may be the activity, yield, or selectivity in the hydrocarbon products of interest, or even HDN, aromatic hydrogenation, or finer product properties such as the cetane number of diesel fuel or the viscosity index of unconverted oil, without these target properties alone constituting a limitation to the scope of the present invention.

[0119] In these hydrocracking processes, the operating conditions are those described below. They may vary in the case where several hydrocracking reactors make up the process according to the implementation rules well known to those skilled in the art.

[0120] Advantageously, the catalyst according to the invention is used in the hydrocracking process according to the invention after a so-called pretreatment section containing one or more hydrotreating catalyst(s), which may be any catalyst known to those skilled in the art, and which reduces the content of certain contaminants in the feedstock, such as nitrogen, sulfur, or metals. The operating conditions (hourly volumetric rate, temperature, pressure, hydrogen flow rate, hydrocarbon flow rate, reaction configuration, etc.) of this so-called pretreatment section may be diverse and varied, in accordance with the knowledge of those skilled in the art.

[0121] Charges

[0122] A wide variety of feedstocks can be processed by the hydrocracking processes according to the invention. The feedstock used in the hydrocracking process according to the invention is preferably a hydrocarbon feedstock of which at least 5% by weight of the compounds have an initial boiling point above 300 °C and a final boiling point below 650 °C, preferably of which at least 30% by weight, preferably of which at least 50% by weight and more preferably of which at least 75% by weight of the compounds, have an initial boiling point above 300 °C and a final boiling point below 650 °C.

[0123] The feedstock is advantageously selected from LCOs (Light Cycle Oil, light gas oils from a catalytic cracking unit), atmospheric distillates, vacuum distillates such as, for example, gas oils from direct distillation of crude oil or from conversion units such as fluidized bed catalytic cracking (or FCC for Fluid Catalytic Cracking according to Anglo-Saxon terminology), coker or visbreaking, feedstocks from units for extracting aromatics from lubricating oil bases or from solvent dewaxing of lubricating oil bases, distillates from desulfurization or hydroconversion processes in fixed or bubbling bed of RATs (atmospheric residues) and / or RSVs (vacuum residues) and / or deasphalted oils, and deasphalted oils, paraffins from the Fischer-Tropsch process, taken alone or in blend.Examples include feedstocks of renewable origin (such as vegetable oils, animal fats, hydrothermal conversion oil, or pyrolysis oil from lignocellulosic biomass) as well as plastic pyrolysis oils. The above list is not exhaustive. These feedstocks preferably have a boiling point (T5) above 300 °C, and more preferably above 340 °C; that is, 95% of the compounds present in the feedstock have a boiling point above 300 °C, and more preferably above 340 °C.

[0124] The nitrogen content of the feedstocks treated in the processes according to the invention is advantageously greater than or equal to 500 ppm by weight, preferably between 500 and 10,000 ppm by weight, more preferably between 700 and 4,000 ppm by weight, and even more preferably between 1,000 and 4,000 ppm by weight. The sulfur content of the feedstocks treated in the processes according to the invention is advantageously between 0.01 and 5% by weight, preferably between 0.2 and 4% by weight, and even more preferably between 0.5 and 3% by weight.

[0125] The feedstock may optionally contain metals. The cumulative nickel and vanadium content of the feedstocks treated in the processes according to the invention is preferably less than 1 ppm by weight.

[0126] The feedstock may optionally contain asphaltenes. The asphaltene content is generally less than 3000 ppm by weight, preferably less than 1000 ppm by weight, and even more preferably less than 200 ppm by weight.

[0127] Advantageously, when the catalyst obtained according to the process according to the invention is implemented after a hydrotreating section as described above, the nitrogen, sulfur, metal or asphaltene contents of the injected liquid In the process according to the invention, which utilizes the catalyst obtained according to the process of the invention, the organic nitrogen content of the feedstock treated in the hydrocracking process according to the invention is reduced. Preferably, the organic nitrogen content of the feedstock treated in the hydrocracking process according to the invention is then, after hydrotreatment, between 0 and 200 ppm, preferably between 0 and 50 ppm, and even more preferably between 0 and 30 ppm. The sulfur content is preferably less than 1000 ppm and the asphaltene content is preferably less than 200 ppm, while the metal (Ni or V) content is less than 1 ppm.

[0128] The hydrocracking process according to the invention may include a fractionation step between the feed pretreatment and the hydrocracking reactor(s) implementing the catalyst according to the invention. In the preferred case where the hydrocracking process is operated without fractionation (gas and liquid) between the pretreatment and the hydrocracking reactor(s) implementing the catalyst obtained according to the process according to the invention, the nitrogen and sulfur removed from the liquid after the pretreatment are injected in the form of NH3 and H2S into the reactor(s) containing the catalyst according to the invention.

[0129] Operating conditions of the hydrocracking process

[0130] Preferably, the hydrocracking process of said hydrocarbon feedstock is carried out at a temperature between 200 °C and 480 °C, at a total pressure between 1 MPa and 25 MPa, with a hydrogen volume to hydrocarbon feedstock volume ratio between 80 and 5000 L / L and at a Volumetric Hourly (WH) defined by the ratio of the volumetric flow rate of hydrocarbon feedstock to the volume of catalyst loaded into the reactor between 0.1 and 50 h'.

[0131] Preferably, the hydrocracking process operates in the presence of hydrogen, at a temperature between 250 and 480 °C, preferably between 320 and 450 °C, most preferably between 330 and 435 °C, under a pressure between 2 and 25 MPa, preferably between 3 and 20 MPa, at a space speed between 0.1 and 20 h', preferably between 0.1 and 6 h', preferably between 0.2 and 3 h', and the quantity of hydrogen introduced is such that the ratio of volume of hydrogen to volume of hydrocarbon feedstock is between 100 and 2000 L / L.

[0132] These operating conditions used in the hydrocracking processes according to the invention generally allow conversions per pass, into products having boiling points below 340 °C, and preferably below 370 °C, greater than 15 wt% and more preferably between 20 and 100 wt%.

[0133] The following examples illustrate the present invention without however limiting its scope. [List of figures]

[0134] Fig. 1 presents the XRD diffractograms of the Ul, RI and R2 catalysts over the range of interplanar distances between 3.1 and 3.5 Å.

[0135] Figure 2 shows the XRD diffractograms of catalysts U2, R3 and R4 over the same range of interplanar spacings. For better readability, the diffractograms are offset from each other along the ordinate axis.

[0136] The diffraction line located at the interplanar spacing d = 3.35 Å is the most intense diffraction line of the NiMoO4 crystalline phase. It is not present on the Ul and R2 catalysts ([Fig. 1]) nor on the U2 and R4 catalysts ([Fig. 2]). However, it is clearly visible on the RI and R3 catalysts.

[0137] The other diffraction lines correspond to the USY zeolite (d = 3.24 Å) and to the internal standard (certified silicon) added to the samples (d = 3.14 Å). Examples

[0138] Example 1: Obtaining the spent catalyst Ul

[0139] A hydrocracking catalyst A was used for 2 years on a pilot hydrocracking unit operated as an industrial vacuum gas oil (VGO) unit. Catalyst A contains 16 wt% MoO3, 3.5 wt% NiO, and 3.0 wt% P2O5, deposited on a support consisting of 80 wt% gamma alumina and 20 wt% USY zeolite having a lattice parameter of 24.28 Å. Catalyst A has a BET surface area of ​​385 m² / g and a pore volume of 0.60 mL / g.

[0140] The hydrocracking unit in which catalyst A was operated has a two-reactor design: a first reactor for hydrotreating the feedstock and a second reactor for the actual hydrocracking. A NiMo / alumina hydrotreating catalyst was loaded into the hydrotreating reactor. Catalyst A was loaded into the second reactor for hydrocracking. The feedstock used was of the VGO type with an average T50 (analyzed by DS) of approximately 430°C and a nitrogen content of 1400 ppm.

[0141] Prior to the injection of the feedstock, the two catalysts were sulfided using straight-run diesel fuel, i.e., diesel fuel obtained from the direct distillation of petroleum, with 4 wt% dimethyl disulfide (DMDS) and 2 wt% aniline added. The sulfidation was carried out at a WH of 2 h⁻¹ (WH = Volumetric Velocity Hourly), a H₂ / feedstock volume ratio of 1000 NL / L, a total pressure of 14 MPa, and a temperature of 350°C for 6 hours.

[0142] After sulfidation, the temperature of the 1st reactor was adjusted to target a nitrogen content at the outlet of this reactor of between 5 and 15 ppm throughout the cycle, and the temperature of the 2nd reactor was adjusted to target a conversion The net conversion of the 370°C+ fraction was approximately 70%; in practice, this temperature varied from 376°C to 400°C. When the 400°C temperature was no longer sufficient to maintain the 70% conversion, the cycle was interrupted. On average, the catalyst therefore underwent a deactivation of 1°C / month.

[0143] After unloading the hydrocracking reactor and after an ex-situ deoiling step (toluene washing at 250°C under reflux), the catalyst was dried under primary vacuum and then analyzed. The resulting spent catalyst U1 contains 6 wt% carbon.

[0144] Example 2: Obtaining the regenerated RI catalyst (comparative)

[0145] A portion of the spent catalyst U1 undergoes regeneration under an oxidizing atmosphere at 480°C for 2 hours with a water-free air flow of 450 NL / L / h. The resulting regenerated catalyst RI contains 0.25 wt% sulfur and is carbon-free. Its metal composition is unchanged compared to the new catalyst A. XRD analysis reveals the presence of a NiMoO4 phase, which was not present on the spent catalyst U1, as illustrated in [Fig. 1]. The catalyst RI has a BET surface area of ​​343 m² / g, representing 89% of the BET surface area of ​​the new catalyst A. It also has a pore volume of 0.57 mL / g, representing 95% of the pore volume of the new catalyst A.

[0146] Example 3: Obtaining the regenerated catalyst R2 (according to the invention)

[0147] Another portion of the spent catalyst Ul undergoes regeneration under an oxidizing atmosphere at 400°C for 2 hours under a water-free air flow of 450 NL / L / h. The resulting regenerated catalyst R2 contains 0.32 wt% carbon and 1.1 wt% sulfur. Its metal composition is unchanged compared to the new catalyst A. No NiMoO4 phase is detectable by XRD analysis, as illustrated in [Fig. 1].

[0148] The catalyst R2 has a BET surface area of ​​362 m2 / g and a pore volume of 0.57 mL / g, which represents respectively 94% of the BET surface area and 95% of the pore volume of the new catalyst A.

[0149] Example 4: Obtaining the spent catalyst U2

[0150] The catalyst A described in Example 1 was also used in the same unit The hydrocracking process was similar to that used in Example 1, but under temperature conditions that allowed for a net conversion of 85% of the 370°C+ fraction to be achieved and maintained throughout the test. The initial temperature was set at 383°C and was gradually increased over time to maintain the specified conversion level. After 2.5 years, and with the target temperature at 418°C, the unit was shut down and the hydrocracking catalyst was discharged. The catalyst therefore underwent an average deactivation rate of approximately 1.2°C / month.

[0151] After a deoiling step, as described in Example 1, the spent catalyst U2 was obtained; it contains 12 wt% of carbon.

[0152] Example 5: Obtaining the regenerated catalyst R3 (comparative)

[0153] A portion of the spent catalyst U2 undergoes regeneration under an oxidizing atmosphere at 480°C for 2 hours under a water-free air flow of 450 NL / L / h. The resulting regenerated catalyst R3 contains 0.14 wt% sulfur and is carbon-free. Its metal composition is unchanged compared to the new catalyst A. XRD analysis reveals the presence of a NiMoO4 phase, which was not present on the spent catalyst U2, as illustrated in [Fig. 2].

[0154] The R3 catalyst has a BET surface area of ​​347 m2 / g, which represents 90% of the BET surface area of ​​the new catalyst A. It also has a pore volume of 0.58 mL / g, which represents 96% of the pore volume of the new catalyst A.

[0155] Example 6: Obtaining the regenerated catalyst R4 (according to the invention)

[0156] Another portion of the spent catalyst U2 undergoes regeneration under an oxidizing atmosphere at 400°C for 2 hours under a water-free air flow of 450 NL / L / h. The resulting regenerated catalyst R4 contains 0.56 wt% carbon and 0.39 wt% sulfur. Its metal composition is unchanged compared to the new catalyst A. No NiMoO4 phase is detectable by XRD analysis, as illustrated in [Fig. 2].

[0157] The R4 catalyst has a BET surface area of ​​370 m2 / g and a pore volume of 0.58 mL / g, which represents respectively 96% of the BET surface area and 96% of the pore volume of the new catalyst A.

[0158] Example 7: Catalytic performance of catalysts A, Ul, RI, R2, U2, R3 and R4

[0159] The performance of the catalysts described above is evaluated in one-step hydrocracking of a feed comprising a distillate fraction under vacuum using an isothermal pilot test unit in downflow configuration.

[0160] This test load has been previously hydrotreated. After this hydrotreatment step, the test load exhibits the properties shown in Table 1 below. In order to simulate the partial pressures of hydrogen sulfide and ammonia generated by the hydrotreatment step of the process, the test load is additively treated with DMDS and aniline, respectively, to obtain 15,300 ppm wt of sulfur and 1,400 ppm wt of nitrogen in the final additively treated load.

[0161] Characteristics of the hydrotreated charge

[0162] [Tables 1] Characteristics Unit Value Density at 15°C g / mL 0.8889 Nitrogen ppm by weight 46 Sulfur ppm by weight 143 Aromatic Carbon % by weight 9.4 Starting Point Simulated Distillation (ASTM 6352) °C 174 T°C 10% Simulated Distillation °C 343 T°C 20% Simulated Distillation °C 381 T°C 30% Simulated Distillation °C 404 T°C 40% Simulated Distillation °C 422 T°C 50% Simulated Distillation °C 439 T°C 60% Simulated Distillation °C 455 T°C 70% Simulated Distillation °C 473 T°C 80% Simulated Distillation °C 494 T°C 90% Simulated Distillation °C 523 Ending Point Simulated Distillation °C 599

[0163] Each catalyst is evaluated separately and is sulfided prior to the hydrocracking test using straight-run diesel fuel with 4 wt% dimethyl disulfide (DMDS) and 2 wt% aniline. The sulfidation is carried out at a WH of 2 h1, a H2 / feed volume ratio of 1000 NL / L, a total pressure of 14 MPa, and a temperature of 350°C for 6 hours.

[0164] After sulfidation, the operating conditions are adjusted to those used for the hydrocracking test: WH of 1.5 h', H2 / feed volume ratio of 1000 NL / L, total pressure of 14 MPa. The reactor temperature is adjusted to target a net conversion of the 375°C+ fraction of 80% after 150 hours under load.

[0165] The performance of the catalysts is compared to that of catalyst A, taken as a reference, and reported in Table 2. The relative activity in degrees Celsius (°C) is obtained by the difference in temperatures required to achieve the same net conversion of 80% between catalyst A and the catalyst being evaluated. A positive value means that the catalyst being evaluated has a higher activity than catalyst A. The HDN is measured as the rate of transformation of the nitrogen present in the load (at the same applied test temperature) without taking aniline into account, according to the following calculation:

[0166] %HDN = (ppmN_charge - ppmN_effluent) / (ppmN_charge)

[0167] The relative volume activity (RVA) is then calculated as follows (assuming that HDN is a first-order reaction):

[0168] RVA_HDN = ln(l / (l-%HDN_catalyst)) / ln(l / (l-%HDN_catalyst_A)) xlOO

[0169] Comparison of the performance of catalysts A (fresh), U1 and U2 (worn catalysts), RI, R2, R3 and R4 (regenerated catalysts). The regeneration temperatures, carbon contents and the possible presence of a NiMoO4 phase, as described in Examples 1 to 6, are shown in this table.

[0170] [Tables2] Regeneration temperature C (% wt. s) Presence of NiMoO4 HCK - Relative activity (°C) HDN-RVA Fresh catalyst A (example 1) ___ ___ No Base 100 Used catalyst U1 (example 1) ___ 6 No -24 60 Regenerated catalyst RI (comparative example 2) 480°C - 2h 0 Yes -5 70 Regenerated catalyst R2 (example 3 according to the invention) 400°C - 2h 0.32 No -1 94 Used catalyst U2 (example 4) ___ 12 No -35 49 Regenerated catalyst R3 (comparative example 5) 480°C - 2h 0 Yes -12 65 Regenerated catalyst R4 (example 6 according to the invention) 400°C - 2h 0.56 No -7 90

[0171] The catalytic performances observed above demonstrate the advantage of regenerating catalysts at a lower temperature (here 400°C) than the temperatures usually applied according to the principles of prior art (480°C for the counterexamples provided). Indeed, the target converting activity, at iso-VVH, pressure and incoming load, is obtained for temperatures 4 and 5°C lower respectively than the temperatures of the comparative examples.

[0172] Furthermore, at iso-temperature test, it is also shown that the efficiency of the catalysts regenerated according to the invention (at 400°C) is increased with 90-94% of the HDN activity of the fresh catalyst, whereas the catalysts regenerated at higher temperatures (480°C) do not allow better than 65-70% of the HDN activity of the fresh catalyst.

[0173] The regeneration process according to the invention is therefore attractive to refiners, who have the possibility of regenerating catalysts with less energy expenditure (lower regeneration temperature) while obtaining higher-performing catalysts, even if the regenerated catalyst may contain residual coke (here 0.32 or 0.56 wt% for the examples according to the invention). Without linking these results to any specific theory, the advantage of the invention could be related to obtaining satisfactory specific surface areas and pore volumes without generating excessive quantities of crystalline phases refractory to sulfidation, such as NiMoO4.

Claims

Demands

1. A process for regenerating a catalyst that is at least partially spent from a hydrocracking process, said catalyst that is at least partially spent being derived from a fresh catalyst comprising at least one metal from Group VIII, at least one metal from Group VIB, and a support comprising at least one USY zeolite, said USY zeolite having a lattice parameter of between 24.10 and 24.70 Å, more preferably between 24.15 and 24.60 Å, even more preferably between 24.20 and 24.56 Å, a Si / Al molar ratio of between 2 and 300, more preferably between 2.5 and 150, even more preferably between 2.5 and 100, a BET surface area greater than 500 m² / g, more preferably between 600 and 1100 m² / g, even more preferably between 750 and 1000 m2 / g, a mesoporous volume between 0.05 and 0.9 mL / g, more preferably between 0.08 and 0.7 mL / g and even more preferably between 0.1 and 0.6 mL / g,said process includes at least one regeneration step in which the at least partially spent catalyst is subjected to thermal and / or hydrothermal treatment in the presence of an oxygen-containing gas at a temperature between 350°C and 460°C so as to obtain a regenerated catalyst, said process not including any subsequent rejuvenation step involving contacting said regenerated catalyst with at least one organic or inorganic, acidic or basic compound.

2. A process according to the preceding claim, wherein the Group VIII metal content in the fresh catalyst is less than 20% by weight, preferably between 0.03 and 15% by weight, most preferably between 0.5 and 10% by weight, and even more preferably between 1 and 8% by weight expressed as Group VIII metal oxide relative to the total weight of the fresh catalyst, and the Group VIB metal content in the fresh catalyst is between 1 and 50% by weight, preferably between 5 and 40% by weight, and most preferably between 10 and 35% by weight expressed as Group VIB metal oxide relative to the total weight of the fresh catalyst.

3. A method according to any one of the preceding claims, wherein the fresh catalyst support comprises said USY zeolite and a Beta zeolite.

4. A process according to any one of the preceding claims, wherein the oxygen content in the gas used in the regeneration step is between 2 and 20% v / v, more preferably between 5 and 20% v / v, and even more preferably the gas used is air alone, the water content in the gas used in the regeneration step is between 0 and 1000 g of water per kg of dry air, preferably between 0 and 500 g of water per kg of dry air, preferably between 0 and 250 g of water per kg of dry air and even more preferably between 0 and 100 g of water per kg of dry air, and the duration of the regeneration step is greater than 1 hour, more preferably between 1 and 100 hours, preferably between 1.5 and 25 hours and particularly preferably between 2 and 10 hours.

5. A method according to any one of the preceding claims, wherein the regeneration step of the at least partially worn catalyst is carried out at a temperature between 360 and 450°C, preferably between 370 and 430°C, and even more preferably between 380 and 420°C.

6. A process according to any one of the preceding claims, wherein the regenerated catalyst contains residual carbon at a content of less than 2% by weight relative to the total weight of the regenerated catalyst, preferably less than 1.5% by weight, most preferably less than 1% by weight and most preferably between 0.01 and 0.8% by weight.

7. A process according to any one of claims 1 to 5, wherein the regenerated catalyst does not contain residual carbon.

8. A process according to any one of the preceding claims, wherein the regenerated catalyst contains residual sulfur at a content of less than 3 wt% relative to the total weight of the regenerated catalyst, preferably less than 2 wt%, preferably between 0.01 wt% and 1.5 wt%, and even more preferably between 0.1 wt% and 1.2 wt%.

9. Use of the catalyst obtained according to the process according to any one of claims 1 to 8 in a process for hydrocracking hydrocarbon fractions.

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