HYDROTREATMENT PROCESS IMPLEMENTING A CHAIN ​​OF CATALYST ENGINEERS WITH A NICKEL AND TUNGSTEN-BASED CATALYST ON A SILICA-ALUMINUM SUPPORT

Abstract

The invention relates to a hydrotreating process for a hydrocarbon feedstock in which at least 50% by weight of the compounds have an initial boiling point above 300°C and a final boiling point below 650°C, so as to obtain a hydrotreated effluent, said process comprising the following steps: a) contacting said hydrocarbon feedstock in the presence of hydrogen with at least a first catalyst comprising an alumina support and an active phase consisting of nickel and molybdenum, b) contacting the effluent obtained in step a) in the presence of hydrogen with at least a second catalyst comprising a silica-alumina support and an active phase consisting of nickel and tungsten, phosphorus and an organic compound.

Description

Title of the invention: HYDROTREATMENT PROCESS IMPLEMENTING A SEQUENCE OF CA TALYSERS WITH A NICKEL AND TUNGSTEN BASED CATALYST ON A SILICA-ALUMINA SUPPORT Technical field

[0001] The invention relates to a process for hydrotreating a hydrocarbon feedstock using a sequence of at least two specific catalysts. The objective of the process is the production of hydrodesulfurized, hydrodenitrogenated and hydrodearomatized hydrocarbon feedstocks.

[0002] Conventional hydrotreatment catalysts generally comprise an oxide support and an active phase based on metals from groups VIB and VIII in their oxide forms as well as phosphorus. The preparation of these catalysts generally comprises a step of impregnation of the metals and phosphorus onto the support, followed by drying and calcination to obtain the active phase in their oxide forms. Before their use in a hydrotreatment and / or hydrocracking reaction, these catalysts are generally subjected to sulfurization in order to form the active species.

[0003] The addition of an organic compound to hydrotreatment catalysts to improve their activity has been recommended by those skilled in the art, particularly for catalysts that have been prepared by impregnation followed by drying without subsequent calcination. These catalysts are often referred to as “additive dried catalysts”.

[0004] Usually, a catalyst for hydrotreating hydrocarbon cuts aims to eliminate the sulfur, nitrogen or aromatic compounds contained in them in order to bring, for example, a petroleum product to the required specifications (sulfur content, aromatic content, etc.) for a given application (automobile fuel, gasoline or diesel, domestic fuel oil, jet fuel).

[0005] Due to the tightening of air quality legislation in many countries, continuous efforts are being made to develop more efficient catalysts and processes for the production of ultra-low sulfur fuels. Although great progress has been made in the development of efficient catalysts for these processes, major challenges remain, for example, their modest saturation activity with aromatic hydrocarbons or hydrodenitrogenation.

[0006] The reduction of the sulfur, nitrogen and aromatic content is thus sought in the field of pretreatment for a hydrocracking process or for a fluidized bed catalytic cracking process (or FCC process for Fluid Catalytic Cracking according to (English terminology) to improve performance in subsequent hydrocracking or FCC stages. These processes generally process feedstocks with high sulfur, nitrogen, and aromatic content.

[0007] However, a hydrotreatment catalyst optimized for hydrodesulfurization (HDS) is not automatically optimized for aromatic saturation (or hydrodearomatization HDA) or for hydrodenitrogenation (HDN) and vice versa. Thus, catalyst sequences are often used in which each catalyst is optimized for one type of hydrotreatment.

[0008] Such sequences of supported catalysts are for example described in documents US2011 / 0079542, US5068025, CN1176290, FR3013720 or FR3013721.

[0009] There are also sequences of unsupported catalysts, also called "bulk" catalysts according to English terminology and known for example from documents US7816299 or CN102851070. The sequence of supported catalysts, however, has the advantage of using regenerable catalysts which are also less expensive (because they are less loaded with metals) and which are also active with a lower metal content.

[0010] Document US2003 / 0116473 discloses a hydrotreatment process using a sequence of a molybdenum-based supported catalyst followed by a tungsten-based supported catalyst. This document does not disclose a volume distribution of the two catalytic zones.

[0011] Document CN105435824 discloses a hydrotreatment process using a sequence of a supported CoMoP catalyst with citric acid additive followed by a supported NiMoWP catalyst. The volume of the first catalyst is between 5 and 95% and the volume of the second catalyst is between 95 and 5%. An increase in HDS and HDN is observed.

[0012] Regardless of the catalyst sequence chosen, the modifications induced do not always allow the performance of the catalytic system to be increased sufficiently to meet the specifications concerning the sulfur, nitrogen and / or aromatic contents of the fuels. Consequently, it appears essential for refiners to find new hydrotreatment processes with improved performance in terms of activity and stability.

[0013] The applicant has developed a process for hydrotreating a hydrocarbon feedstock comprising bringing said feedstock into contact with a specific sequence of catalysts making it possible to increase the overall activity and overall stability of the process. Summary

[0014] The invention relates to a process for hydrotreating a hydrocarbon feedstock of which at least 50% by weight of the compounds have an initial boiling point higher than 300°C and a final boiling point below 650°C, at a temperature between 180°C and 450°C, a pressure between 0.5 and 30 MPa, an hourly volumetric flow rate between 0.1 and 20 h 1 and a hydrogen / feed ratio expressed in volume of hydrogen, measured under normal temperature and pressure conditions, per volume of liquid feed between 50 NL / L and 5000 NL / L, so as to obtain a hydrotreated effluent, said process comprising the following steps

[0015] a) a first hydrotreatment step implemented in a first hydrotreatment reaction section, implementing at least one catalytic bed comprising at least one first hydrotreatment catalyst, said hydrotreatment reaction section being fed with at least said hydrocarbon feedstock and a gas stream comprising hydrogen, said first catalyst comprising an alumina support, an active phase consisting of nickel and molybdenum, and optionally phosphorus and / or optionally an organic compound containing oxygen and / or nitrogen and / or sulfur,

[0016] b) a second hydrotreatment step carried out in a second hydrotreatment reaction section, using at least one catalytic bed comprising at least one second hydrotreatment catalyst, said hydrotreatment reaction section being fed with at least a portion of the effluent obtained in step a), said second catalyst comprising a silica-alumina support, an active phase consisting of nickel and tungsten, phosphorus, and an organic compound containing oxygen and / or nitrogen and / or sulfur.

[0017] The applicant has surprisingly discovered that a sequence of a first hydrotreatment reaction section containing a first catalyst based on an active phase consisting of nickel and molybdenum on an alumina support and a second hydrotreatment reaction section containing a second catalyst based on an active phase consisting of nickel and tungsten on a more acidic support in the presence of phosphorus and an organic compound has a synergistic effect in terms of activity and stability in hydrotreatment, in particular in hydrogenation of aromatics (HDA) but also in hydrodenitrogenation (HDN) and / or in hydrodesulfurization (HDS).

[0018] Indeed, the choice of the right active phase, of a suitable support, of the presence of phosphorus and / or of an organic compound for each catalyst makes it possible to observe a symbiosis of the first catalyst based on an active phase consisting of nickel and molybdenum on a non-acidic or slightly acidic support (alumina), carrying out in particular the HDS and part of the HDN, followed by the second catalyst based on an active phase consisting of nickel and tungsten in the presence of phosphorus and of an organic compound on a more acidic support (silica-alumina), allowing the modification of the structure of the most refractory aromatic compounds (by isomerization and / or cracking reactions), making these molecules more reactive, thus promoting HDA, a prerequisite for increasing HDN, in particular thanks to tungsten which provides a gain in hydrogenating activity.

[0019] On the one hand, the second catalyst is very active, particularly in HDA and HDN, which makes it possible to complete the hydrotreatment reactions, particularly HDS and HDN, of the first catalyst necessary to achieve the specifications. Similarly, stability is increased, because the cycle time is extended thanks to the reduction in temperature necessary to carry out the HDS, HDN and HDA reactions.

[0020] On the other hand, the second catalyst deactivates less quickly, which makes it possible to increase the cycle time on a standard load or to allow the treatment of loads heavily loaded with sulfur, nitrogen and / or aromatics.

[0021] The hydrotreatment process according to the invention is particularly suitable for a vacuum distillate feedstock. The hydrotreatment process according to the invention is also particularly suitable for the hydrotreatment of feedstocks comprising high nitrogen and aromatic contents, such as feedstocks from catalytic cracking, coker or visbreaking.

[0022] The process according to the present invention makes it possible to produce a hydrotreated hydrocarbon cut, that is to say one freed from nitrogen compounds, sulfur compounds and most aromatic compounds. Preferably, according to the process according to the invention, the conversion in hydrodesulfurization (HDS) is greater than 95%, preferably greater than 98%. Preferably, according to the process according to the invention, the conversion in hydrodenitrogenation (HDN) is greater than 90%, preferably greater than 95%. Preferably, according to the process according to the invention, the conversion in hydrogenation of aromatics (HDA) is greater than 35%, preferably greater than 40%.

[0023] According to a variant, said first hydrotreatment reaction section containing the first catalyst occupies a volume VI, and said second hydrotreatment reaction section containing the second catalyst occupies a volume V2, the distribution of the volumes V1 / V2 being between 50% vol / 50% vol and 90% vol / 10% vol respectively.

[0024] The volume distribution of the two catalysts, in particular the fact that the second reaction section containing the second catalyst occupies a smaller volume than the first reaction section containing the first catalyst, makes it possible to optimize the HDS, HDN and HDA reactions carried out in the first or second reaction section in order to obtain hydrocarbon cuts to the specifications while increasing the activity and stability of the catalytic system compared to to a system containing only one of the catalysts.

[0025] According to a variant, the distribution of volumes V1 / V2 is between 70% vol / 30% vol and 80% vol / 20% vol respectively of said first and second hydrotreatment reaction section.

[0026] According to a variant, the second catalyst is characterized in that:

[0027] - the nickel content, expressed in the form of NiO, is between 1.2 and 4.5% by weight relative to the total weight of the catalyst,

[0028] - the tungsten content, expressed in the form WO3, is between 16 and 33% weight relative to the total weight of the catalyst,

[0029] - the phosphorus content, expressed in the form of P2O5, is between 1 and 4% weight relative to the total weight of the catalyst.

[0030] According to a variant, the second catalyst is characterized in that:

[0031] - the nickel content, expressed in the form of NiO, is between 1.3 and 4.3% by weight relative to the total weight of the catalyst,

[0032] - the tungsten content, expressed in the form WO3, is between 17 and 31% weight relative to the total weight of the catalyst,

[0033] - the phosphorus content, expressed in the form P2O5, is preferably between 1.3 and 3.4% by weight relative to the total weight of the catalyst.

[0034] According to this variant, the second catalyst is further characterized in that:

[0035] - the molar ratio Ni / W is between 0.18 and 0.45 mol / mol,

[0036] - the P / W molar ratio is between 0.18 and 0.45 mol / mol.

[0037] According to one variant, the silica content in the support of the second catalyst is between 10 and 50% by weight relative to the total weight of the support.

[0038] According to a variant, the first catalyst has a molybdenum content of between 5 and 40% by weight, expressed as MoO3, relative to the total weight of the catalyst and a nickel content of between 1 and 10% by weight, expressed as NiO, relative to the total weight of the catalyst.

[0039] According to a variant, the first catalyst further comprises phosphorus at a content of between 0.1 and 20% by weight expressed as P2O5 relative to the total weight of the catalyst.

[0040] According to one variant, the first catalyst further contains an organic compound containing oxygen and / or nitrogen and / or sulfur.

[0041] According to a variant, the organic compound is chosen from a compound comprising one or more chemical functions chosen from a carboxylic function, alcohol, thiol, thioether, sulfone, sulfoxide, ether, aldehyde, ketone, ester, carbonate, amine, nitrile, imide, oxime, urea, amide or even compounds including a furan cycle or even a sugar, and preferably it is chosen from γ-valerolactone, 2-acetylbutyrolactone, triethylene glycol, diethylene glycol, ethylene glycol, ethylenediaminetetraacetic acid (EDTA), maleic acid, malonic acid, citric acid, acetic acid, oxalic acid, gluconic acid, glucose, fructose, sucrose, sorbitol, xylitol, y-ketovaleric acid, a C1-C4 dialkyl succinate and more particularly dimethyl succinate, dimethylformamide, l-methyl-2-pyrrolidinone, propylene carbonate, 2-methoxyethyl 3-oxobutanoate, bicine, tricine, 2-furaldehyde (also known as furfural), 5-hydroxymethylfurfural, 2-acetylfuran, 5-methyl-2-furaldehyde, ascorbic acid, butyl lactate, ethyl lactate, butyl butyryllactate, ethyl 3-hydroxybutanoate, ethyl 3-ethoxypropanoate, 2-ethoxyethyl acetate, 2-butoxyethyl acetate, 2-hydroxyethyl acrylate, l-vinyl-2-pyrrolidinone, l,3-dimethyl-2-imidazolidinone, 1,5-pentanediol, l-(2-hydroxyethyl)-2-pyrrolidinone, l-(2-hydroxyethyl)-2,5-pyrrolidinedione, 5-methyl-2(3H)-furanone, l-methyl-2-piperidinone, 4-aminobutanoic acid, butyl glycolate, ethyl 2-mercaptopropanoate, ethyl 4-oxopentanoate, diethyl maleate, dimethyl maleate, dimethyl fumarate, diethyl fumarate, dimethyl adipate and dimethyl 3-oxoglutarate. ,

[0042] According to one variant, the organic compound content is between 1 and 30% by weight relative to the total weight of the catalyst.

[0043] According to one variant, the first and / or the second catalyst is at least partially sulfurized.

[0044] According to one variant, the hydrotreatment process is implemented as pretreatment in a fluidized bed catalytic cracking process.

[0045] According to one variant, the hydrotreatment process is implemented as pretreatment in a hydrocracking process. Detailed description of the invention Definitions

[0046] According to the present invention, the expressions "between ... and..." and "between .... and..." are equivalent and mean that the limit values ​​of the interval are included in the range of values ​​described. If this were not the case and the limit values ​​were not included in the range described, such precision will be provided by the present invention.

[0047] 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 range of preferred pressure values ​​can be combined with a range of more preferred temperature values.

[0048] In the following, particular and / or preferred embodiments of the invention may be described. They may be implemented separately or combined with each other, without limitation of combination when technically feasible.

[0049] According to the present invention, the pressures are absolute pressures, also noted abs., and are given in absolute MPa (or MPa abs.), unless otherwise indicated.

[0050] 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.

[0051] Specific surface area means the BET specific surface area (SBet in m2 / g) determined by nitrogen adsorption in accordance with ASTM D 3663-78 established from the BRUNAUER-EMMETT-TELLER method described in the periodical "The Journal of American Society", 1938, 60, 309.

[0052] The total pore volume of the catalyst or support used for the preparation of the catalyst is understood to be the volume measured by intrusion with a mercury porosimeter according to ASTM D4284-83 at a maximum pressure of 4000 bar (400 MPa), using a surface tension of 484 dyne / cm and a contact angle of 140°. The wetting angle was taken as 140° following the recommendations of the work “Techniques de l'ingénieur, traité analyse et caractérisation”, pages 1050-1055, written by Jean Charpin and Bernard Rasneur. In order to obtain better precision, the value of the total pore volume corresponds to the value of the total pore volume measured by intrusion with a mercury porosimeter measured on the sample minus the value of the total pore volume measured by intrusion with a mercury porosimeter measured on the same sample for a pressure corresponding to 30 psi (approximately 0.2 MPa).

[0053] The contents of group VIII and group VIB metals are measured by X-ray fluorescence.

[0054] The contents of group VIB metal, group VIII metal and phosphorus in the catalyst are expressed as oxides after correction for the loss on ignition of the catalyst sample at 550°C for two hours in a muffle furnace. The loss on ignition is due to the loss of volatile compounds. It is determined according to ASTM D7348.

[0055] Hydrotreatment is understood to mean reactions including in particular hydrodesulfurization (HDS), hydrodenitrogenation (HDN) and hydrogenation of aromatics (HD A). The charge

[0056] The feedstock used in the hydrocracking process according to the invention is a hydrocarbon feedstock of which at least 50% 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 60% by weight, preferably of which at least 75% by weight and more preferably of which at least 80% by weight of the compounds have an initial boiling point above 300°C and a final boiling point below 650°C. Said charges preferably have a boiling point T5 above 300°C, preferably above 340°C, i.e. 95% of the compounds present in the charge have a boiling point above 300°C, and preferably above 340°C.

[0057] A wide variety of feedstocks can be treated by the hydrocracking processes according to the invention. The hydrocarbon feedstock is advantageously chosen from HCO (Heavy Cycle Oil according to the English terminology (heavy gas oils from a catalytic cracking unit)), vacuum distillates, for example gas oils from the direct distillation of crude or from conversion units such as catalytic cracking, coker or visbreaking, feedstocks from aromatic extraction units, lubricating oil bases or from solvent dewaxing of lubricating oil bases, distillates from fixed bed or ebullated bed desulfurization or hydroconversion processes of atmospheric residues and / or vacuum residues and / or deasphalted oils, or the feedstock may be a deasphalted oil or comprise vegetable oils or even come from the conversion of feedstocks from biomass.It can also be paraffins from the Fischer-Tropsch process. Said hydrocarbon feedstock treated according to the hydrocracking process of the invention can also be a mixture of said feedstocks mentioned above. Preferably, the feedstock is a vacuum distillate.

[0058] The fillers which are treated, and in particular those mentioned above, generally contain heteroatoms such as sulfur, oxygen and nitrogen and, for heavy fillers, they most often also contain metals.

[0059] The nitrogen content of the feedstocks treated in the processes according to the invention is generally greater than 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.

[0060] The sulfur content of the feedstocks treated in the processes according to the invention is generally 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.

[0061] Said hydrocarbon feedstock may optionally contain metals, in particular nickel and vanadium. The cumulative nickel and vanadium content of said hydrocarbon feedstock is preferably less than 50 ppm by weight, preferably less than 25 ppm, even more preferably less than 10 ppm.

[0062] Said hydrocarbon feedstock may optionally contain asphaltenes. The asphaltene content of said hydrocarbon feedstock is generally less than 3000 ppm, preferably less than 1000 ppm, even more preferably less at 200 ppm.

[0063] Said hydrocarbon feedstock may optionally contain resins. The resin content may be greater than 1% by weight, in particular greater than 5% by weight. The resin content is measured according to ASTM D 2007-11. The hydrocarbon feedstock may also contain very little resin (less than 1% by weight).

[0064] The hydrocarbon feedstock may be of any chemical nature, that is to say, it may have, apart from the aromatic content described below, any distribution between the different chemical families chosen from paraffins, olefins and naphthenes.

[0065] The aromatic content in the feedstock is greater than or equal to 20% by weight, preferably it is between 25 and 90% by weight, more preferably between 30 and 80% by weight. The aromatic content is determined according to the method described in the publication Burdett RA, Taylor LW and Jones LC, Journal of Molecular Spectroscopy, Rept. Conf., Inst. Petroleum, London 1954, 30-41 (Pub. 1955).

[0066] Implementation of the process and operating conditions

[0067] The process according to the invention can be carried out in one, two or more reactors. It is generally carried out in a fixed bed.

[0068] When the process according to the invention is carried out in two reactors, step a) can be carried out in the first reactor containing the first reaction section crossed by the feedstock, then step b) can be carried out in the second reactor containing the second reaction section, placed downstream of the first reactor. Optionally, the effluent from step a) leaving the first reactor can be subjected to a separation step making it possible to separate a light fraction containing in particular the H2S and the NH3 formed during the hydrotreatment in step a) from a heavy fraction containing the partially hydrotreated hydrocarbons. The heavy fraction obtained after the separation step is then introduced into the second reactor making it possible to carry out step b) of the process according to the invention. The separation step can be carried out by distillation, flash separation or any other method known to those skilled in the art.

[0069] When the process is carried out in a single reactor, step a) is carried out in a first zone containing the first reaction section, and step b) is carried out in a second zone containing the second reaction section downstream of the first zone.

[0070] Said first hydrotreatment reaction section containing the first catalyst occupies a volume VI, and said second hydrotreatment reaction section containing the second catalyst occupies a volume V2, the distribution of volumes V1 / V2 generally being between 50%vol / 50%vol and 90%vol / 10%vol, preferably between 60%vol / 40%vol and 85%vol / 15%vol and particularly preferably between 70% vol / 30% vol and 80% vol / 20% vol, respectively of said first and second hydrotreatment reaction sections.

[0071] The volume distribution of the two catalysts, in particular the fact that the second reaction section containing the second catalyst occupies a smaller volume than the first reaction section containing the first catalyst, makes it possible to optimize the HDS, HDN and HDA reactions carried out in the first or second reaction section. Indeed, a volume of the second catalyst that is too large does not allow the quantitative reduction of the nitrogen compounds, thus resulting in an inhibition of the HDA reaction. Conversely, a volume of the second catalyst that is too small does not allow the HDA reaction to be maximized.

[0072] The operating conditions used in steps a) or b) of the hydrotreatment process according to the invention are generally the following: the temperature is advantageously between 180 and 450°C, and preferably between 250 and 440°C, the pressure is advantageously between 0.5 and 30 MPa, and preferably between 1 and 18 MPa, the hourly volumetric flow rate is advantageously between 0.1 and 20 h 1 and preferably between 0.2 and 5 h1. The hourly volumetric flow rate (HV) is defined here as the ratio between the hourly volumetric flow rate of the hydrocarbon feedstock and the volume of catalyst(s). The hydrogen / feedstock ratio expressed as the volume of hydrogen, measured under normal temperature and pressure conditions, per volume of liquid feedstock is advantageously between 50 L / L and 5000 L / L and preferably 80 to 2000 L / L.

[0073] The operating conditions may be identical or different in steps a) and b). Preferably, they are identical.

[0074] Composition of the catalysts used in the invention

[0075] According to the invention, the hydrotreatment process implements a sequence of a first catalyst comprising an alumina support and an active phase consisting of nickel and molybdenum, and optionally phosphorus and / or an organic compound, and a second catalyst comprising a silica-alumina-based support and an active phase consisting of nickel and tungsten, phosphorus and an organic compound.

[0076] First catalyst

[0077] The first catalyst comprises an alumina support and an active phase consisting of nickel and molybdenum. It may further comprise phosphorus, an organic compound, and optionally boron and / or fluorine.

[0078] The hydrogenating function of said first catalyst, also called active phase, is provided by nickel and molybdenum.

[0079] Preferably, the total content of nickel and molybdenum is advantageously su- greater than 6% by weight expressed as oxide relative to the total weight of the catalyst.

[0080] Preferably, the molybdenum content, expressed in the form of MoO3, is between 5 and 40% by weight, preferably between 8 and 39% by weight, and more preferably between 10 and 38% by weight relative to the total weight of the catalyst.

[0081] Preferably, the nickel content, expressed in the form of NiO, is between 1 and 10% by weight, preferably between 1.5 and 9% by weight, and more preferably between 2 and 8% by weight relative to the total weight of the catalyst.

[0082] Preferably, the nickel to molybdenum molar ratio in the first catalyst is preferably between 0.1 and 0.8, preferably between 0.15 and 0.6 and even more preferably between 0.2 and 0.5.

[0083] The first catalyst may also comprise phosphorus as a dopant. The dopant is an added element which in itself has no catalytic character but which increases the catalytic activity of the active phase.

[0084] The phosphorus content in said catalyst, expressed in the form of P2O5, is between 0.1 and 20% by weight relative to the total weight of the catalyst, preferably between 0.2 and 15% by weight, and very preferably between 0.3 and 11% by weight expressed as P2O5.

[0085] The phosphorus to molybdenum molar ratio in the first catalyst is greater than or equal to 0.05, preferably greater than or equal to 0.07, preferably between 0.08 and 1, preferably between 0.1 and 0.9 and very preferably between 0.15 and 0.8.

[0086] The first catalyst may advantageously also contain at least one dopant chosen from boron, fluorine and a mixture of boron and fluorine.

[0087] When the catalyst contains boron or fluorine or a mixture of boron and fluorine, the content of boron or fluorine or a mixture of the two is preferably between 0.1 and 10% by weight expressed as boron oxide and / or fluorine element relative to the total weight of the catalyst, preferably between 0.2 and 7% by weight, and very preferably between 0.2 and 5% by weight.

[0088] The pore volume of said catalyst is generally between 0.1 cmVg and 1.5 cmVg, preferably between 0.15 cmVg and 1.1 cmVg. The total pore volume is measured by mercury porosimetry according to the ASTM D4284 standard with a wetting angle of 140°, as described in the work Rouquerol F.; Rouquerol J.; Singh K. “Adsorption by Powders & Porous Solids: Principle, methodology and applications”, Academie Press, 1999, for example using an Autopore III™ model device from the Micromeritics™ brand.

[0089] The first catalyst is characterized by a specific surface area of ​​between 5 and 400 m2 / g, preferably between 10 and 350 m2 / g, preferably between 40 and 350 m2 / g, very preferably between 50 and 300 m2 / g. The surface area specific is determined in the present invention by the BET method according to ASTM D3663, method described in the same work cited above.

[0090] The support comprises alumina, and preferably extruded alumina. Preferably, the support is made of alumina, preferably gamma alumina.

[0091] The alumina support advantageously has a total pore volume of between 0.1 and 1.5 cm3.g *, preferably between 0.4 and 1.1 cm3.g *. The total pore volume is measured by mercury porosimetry according to the ASTM D4284 standard with a wetting angle of 140°, as described in the work Rouquerol F.; Rouquerol J.; Singh K. “Adsorption by Powders & Porous Solids: Principle, methodology and applications”, Academie Press, 1999, for example using an Autopore III™ model device from the Micromeritics™ brand.

[0092] The specific surface area of ​​the alumina support is advantageously between 5 and 400 m2.g *, preferably between 10 and 350 m2.g *, more preferably between 40 and 350 m2.g 1. The specific surface area is determined in the present invention by the BET method according to standard ASTM D3663, a method described in the same work cited above.

[0093] The support is advantageously in the form of balls, extrudates, pellets or irregular and non-spherical agglomerates whose specific shape can result from a crushing step.

[0094] The first catalyst may further comprise an organic compound or a group of organic compounds known for their role as additives. The function of the additives is to increase the catalytic activity compared to non-additive catalysts. More particularly, the catalyst may further comprise one or more oxygen-containing organic compounds and / or one or more nitrogen-containing organic compounds and / or one or more sulfur-containing organic compounds. Preferably, the catalyst may further comprise one or more oxygen-containing organic compounds and / or one or more nitrogen-containing organic compounds. Preferably, the organic compound contains at least 2 carbon atoms and at least one oxygen and / or nitrogen atom, without containing other heteroatoms.

[0095] Generally, the organic compound is chosen from a compound comprising one or more chemical functions chosen from a carboxylic function, alcohol, thiol, thioether, sulfone, sulfoxide, ether, aldehyde, ketone, ester, carbonate, amine, nitrile, imide, oxime, urea and amide or even compounds including a furanic cycle or even a sugar.

[0096] The organic compound containing oxygen may be one or more chosen from compounds comprising one or more chemical functions chosen from a carboxylic, alcohol, ether, aldehyde, ketone, ester or carbonate function or also compounds including a furan ring or sugars. Here, an organic compound containing oxygen is understood to mean a compound containing no other heteroatom. For example, the oxygen-containing organic compound may be one or more selected from the group consisting of ethylene glycol, diethylene glycol, triethylene glycol, a polyethylene glycol (with a molecular weight of 200 to 1500 g / mol), propylene glycol, 2-butoxyethanol, 2-(2-butoxyethoxy)ethanol, 2-(2-methoxyethoxy)ethanol, triethylene glycol dimethyl ether, glycerol, acetophenone, 2,4-pentanedione, pentanone, acetic acid, oxalic acid, maleic acid, malic acid, malonic acid, oxalic acid, gluconic acid, tartaric acid, citric acid, γ-ketovaleric acid, a C1-C4 dialkyl succinate and more. particularly dimethyl succinate, methyl acetoacetate, ethyl acetoacetate,2-methoxyethyl 3-oxobutanoate, 2-methacryloyloxyethyl 3-oxobutanoate, dibenzofuran, crown ether, orthophthalic acid, glucose, fructose, sucrose, sorbitol, xylitol, y-valerolactone, 2-acetylbutyrolactone, propylene carbonate, 2-furaldehyde (also known as furfural), 5-hydroxymethylfurfural (also known as 5-(hydroxymethyl)-2-furaldehyde or 5-HMF), 2-acetylfuran, 5-methyl-2-furaldehyde, methyl 2-furoate, furfuryl alcohol (also known as furfuranol), furfuryl acetate, ascorbic acid, butyl lactate, ethyl lactate, butyl butyryllactate, ethyl 3-hydroxybutanoate, ethyl 3-ethoxypropanoate, methyl 3-methoxypropanoate, 2-ethoxyethyl acetate, 2-butoxyethyl acetate, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,5-hexanediol, 3-ethyl-1,5-pentanediol,2,4-diethyl-1,5-pentanediol, 5-methyl-2(3H)-furanone, butyl glycolate, ethyl 4-oxo-pentanoate, diethyl maleate, dimethyl maleate, dimethyl fumarate, diethyl fumarate, dimethyl adipate, dimethyl 3-oxoglutarate, dimethyl tartrate, diethyl tartrate, diisopropyl tartrate, di-tert-butyl tartrate, dimethyl malate, diethyl malate, diisopropyl malate and dibutyl malate.

[0097] The nitrogen-containing organic compound may be one or more selected from compounds comprising one or more chemical functions selected from an amine or nitrile function. Here, a nitrogen-containing organic compound is understood to mean a compound not comprising any other heteroatom. For example, the nitrogen-containing organic compound may be one or more selected from the group consisting of ethylenediamine, diethylenetriamine, hexamethylenediamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, acetonitrile, octylamine, guanidine or a carbazole.

[0098] The organic compound containing oxygen and nitrogen may be one or more chosen from compounds comprising one or more chemical functions chosen from a carboxylic acid, alcohol, ether, aldehyde, ketone, ester, carbonate, amine, nitrile, imide, amide, urea or oxime function. Here, an organic compound containing oxygen and nitrogen is understood to mean a compound not comprising any other heteroatom.For example, the organic compound containing oxygen and nitrogen may be one or more selected from the group consisting of 1,2-cyclohexanediaminetetraacetic acid, monoethanolamine (MEA), l-methyl-2-pyrrolidinone, dimethylformamide, ethylenediaminetetraacetic acid (EDTA), alanine, glycine, nitrilotriacetic acid (NTA), N-(2-hydroxyethyl)ethylenediamine-N,N',N'-triacetic acid (HEDTA), diethylenetriaminepentaacetic acid (DTPA), tetramethylurea, glutamic acid, dimethylglyoxime, bicine, tricine, 2-methoxyethyl cyanoacetate, l-ethyl-2-pyrrolidinone, l-vinyl-2-pyrrolidinone, l,3-dimethyl-2-imidazolidinone, l-(2-hydroxyethyl)-2-pyrrolidinone, l-(2-hydroxyethyl)-2,5-pyrrolidinedione, l-methyl-2-piperidinone, l-acetyl-2-azepanone, l-vinyl-2-azepanone and 4-aminobutanoic acid.

[0099] The sulfur-containing organic compound may be one or more selected from compounds comprising one or more chemical functions selected from a thiol, thioether, sulfone or sulfoxide function. For example, the sulfur-containing organic compound may be one or more selected from the group consisting of thioglycolic acid, 2,2'-thiodiethanol, 2-hydroxy-4-methylthiobutanoic acid, a sulfonated derivative of a benzothiophene or a sulfoxidized derivative of a benzothiophene, ethyl 2-mercaptopropanoate, methyl 3-(methylthio)propanoate and ethyl 3-(methylthio)propanoate.

[0100] Preferably, the organic compound contains oxygen, preferably it is chosen from γ-valerolactone, 2-acetylbutyrolactone, triethylene glycol, diethylene glycol, ethylene glycol, ethylenediaminetetraacetic acid (EDTA), maleic acid, malonic acid, citric acid, acetic acid, oxalic acid, gluconic acid, glucose, fructose, sucrose, sorbitol, xylitol, γ-ketovaleric acid, a C1-C4 dialkyl succinate and more particularly dimethyl succinate, dimethylformamide, 1-methyl-2-pyrrolidinone, propylene carbonate, 2-methoxyethyl 3-oxobutanoate, bicine, tricine, 2-furaldehyde (also known as furfural), 5-hydroxymethylfurfural (also known as 5-(hydroxymethyl)-2-furaldehyde or 5-HMF), 2-acetylfuran, 5-methyl-2-furaldehyde, ascorbic acid, butyl lactate, ethyl lactate, butyl butyryllactate, ethyl 3-hydroxybutanoate,ethyl 3-ethoxypropanoate, 2-ethoxyethyl acetate, 2-butoxyethyl acetate, acrylate, 2-hydroxy ethyl, l-vinyl-2-pyrrolidinone, l,3-dimethyl-2-imidazolidinone, 1,5-pentanediol, l-(2-hydroxyethyl)-2-pyrrolidinone, l-(2-hydroxyethyl)-2,5-pyrrolidinedione, 5-methyl-2(3H)-furanone, l-methyl-2-piperidinone, 4-aminobutanoic acid, butyl glycolate, ethyl 2-mercaptopropanoate, ethyl 4-oxopentanoate, diethyl maleate, dimethyl maleate, dimethyl fumarate, diethyl fumarate, dimethyl adipate and dimethyl 3-oxoglutarate.

[0101] When it is / are present, the total content of organic compound(s) containing oxygen and / or nitrogen and / or sulfur present in the catalyst is generally 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 catalyst.

[0102] When preparing the catalyst requiring a drying step, the drying step(s) following the introduction of the organic compound is (are) carried out at a temperature below 200°C so as to preferably retain at least 30%, preferably at least 50%, and very preferably at least 70% of the quantity of the organic compound introduced calculated on the basis of the carbon remaining on the catalyst. The remaining carbon is measured by elemental analysis according to ASTM D5373.

[0103] Second catalyst

[0104] According to the invention, the second catalyst comprises a silica-alumina support and an active phase consisting of nickel and tungsten. The second catalyst according to the invention also comprises phosphorus as a dopant and an organic compound. It may further comprise boron and / or fluorine.

[0105] The hydrogenating function of said second catalyst, also called active phase, consists of nickel and tungsten.

[0106] The second catalyst is characterized in that:

[0107] - the nickel content, expressed in the form of NiO, is between 1.2 and 4.5% by weight relative to the total weight of the catalyst,

[0108] - the tungsten content, expressed in the form WO3, is between 16 and 33% weight relative to the total weight of the catalyst,

[0109] - the phosphorus content, expressed in the form of P2O5, is between 1 and 4% weight relative to the total weight of the catalyst.

[0110] Preferably, the second catalyst is characterized in that:

[0111] - the nickel content, expressed in the form of NiO, is between 1.3 and 4.3% by weight relative to the total weight of the catalyst, preferably between 1.4 and 3.8% by weight, and more preferably between 1.5 and 3.4% by weight,

[0112] - the tungsten content, expressed in the form WO3, is between 17 and 31% weight relative to the total weight of the catalyst, preferably between 18 and 30% by weight, preferably between 19 and 29% by weight, and more preferably between 20 and 26% by weight,

[0113] - the phosphorus content, expressed in the form P2O5, is preferably between 1.3 and 3.4% by weight relative to the total weight of the catalyst, preferably between 1.4 and 3.1% by weight, and very preferably between 1.5 and 2.8% by weight.

[0114] Preferably, the Ni / W molar ratio is between 0.18 and 0.45 mol / mol, preferably between 0.20 and 0.43 mol / mol and even more preferably between 0.22 and 0.42 mol / mol.

[0115] Preferably, the P / W molar ratio is between 0.18 and 0.45 mol / mol, preferably between 0.20 and 0.43 mol / mol and even more preferably between 0.22 and 0.42 mol / mol.

[0116] The catalyst based on an active phase consisting of nickel and tungsten in the presence of phosphorus and an organic compound, deposited on a silica-alumina support, and having the specific ratios between the different metals and / or phosphorus described above, has, by synergistic effect, excellent activity and stability in hydrotreatment, and in particular in hydrodenitrogenation (HDN) and in hydrogenation of aromatics (HDA) but also in hydrodesulfurization (HDS).

[0117] Without wishing to be bound by any theory, the silica-alumina support of the second catalyst would make it possible to modify the structure of the most refractory aromatic compounds (by isomerization and / or cracking reactions), making these molecules more reactive. Consequently, an optimization of the content of each metal (in particular tungsten which provides a benefit in terms of hydrogenation) and phosphorus using specific ratios, combined with the silica-alumina support, makes it possible to increase the HDA prerequisite for increasing the HDN, inducing an overall improvement in catalytic performance.

[0118] The second catalyst having the specific ratios mentioned below is therefore particularly preferred when chained with said first catalyst upstream.

[0119] The second catalyst may advantageously further contain at least one dopant chosen from boron, fluorine and a mixture of boron and fluorine. When this dopant is present, its content is as described for the first catalyst.

[0120] The pore volume of the second catalyst is generally between 0.1 cmVg and 1.5 cmVg, preferably between 0.15 cmVg and 1.1 cmVg. The total pore volume is measured by mercury porosimetry according to ASTM D4284 with a wetting angle of 140°, as described in the work Rouquerol F.; Rouquerol J.; Singh K. “Adsorption by Powders & Porous Solids: Principle, methodology and applications”, Academie Press, 1999, for example using an Autopore III™ model device from Micromeritics™.

[0121] The second catalyst is characterized by a specific surface area of ​​between 5 and 400 m2 / g, preferably of between 10 and 350 m2 / g, preferably of between 40 and 350 m2 / g, very preferably between 50 and 300 m2 / g. The specific surface area is determined in the present invention by the BET method according to standard ASTM D3663, a method described in the same work cited above.

[0122] The support of the second catalyst is preferably made of a silica-alumina.

[0123] The silica-alumina support advantageously has a total pore volume of between 0.1 and 1.5 cm3.g ', preferably between 0.2 and 0.8 cm3.g 1 and particularly preferably between 0.3 and 0.6 cm3.g '. The total pore volume is measured by mercury porosimetry according to the ASTM D4284 standard with a wetting angle of 140°, as described in the work Rouquerol F.; Rouquerol J.; Singh K. "Adsorption by Powders & Porous Solids: Principle, methodology and applications", Academie Press, 1999, for example using an Autopore III™ model device from the Micromeritics™ brand.

[0124] The specific surface area of ​​the silica-alumina support is advantageously between 5 and 400 m2.g *, preferably between 100 and 350 m2.g *, more preferably between 200 and 300 m2.g 1. The specific surface area is determined in the present invention by the BET method according to standard ASTM D3663, a method described in the same work cited above.

[0125] The silica content in the support is at most 50% by weight relative to the total weight of the support, most often less than or equal to 45% by weight, preferably less than or equal to 40%. Preferably, the silica content in the support is between 10 and 50% by weight, preferably between 15 and 40% by weight and particularly preferably between 20 and 35% by weight relative to the total weight of the support.

[0126] Sources of silicon are well known to those skilled in the art. Examples that may be mentioned are silicic acid, silica in powder form or in colloidal form (silica sol), tetraethylorthosilicate Si(OEt)4.

[0127] The silica-alumina support may also advantageously further contain a zeolite. In this case, all sources of zeolites and all associated preparation methods known to those skilled in the art may be incorporated. Preferably, the zeolite is chosen from the FAU, BEA, ISV, IWR, IWW, MEI, UWY group and preferably, the zeolite is chosen from the FAU and BEA group, such as zeolite Y and / or beta, and particularly preferably such as zeolite USY and / or beta. When the zeolite is present, its content is from 0.1 to 50% by weight relative to the total weight of the support, preferably between 0.1 and 10% by weight.

[0128] The support is advantageously in the form of balls, extrudates, pellets or irregular and non-spherical agglomerates whose specific shape can result from a crushing step.

[0129] The second catalyst according to the invention further comprises an organic compound or a group of organic compounds whose nature and quantities used are described in the part for the first catalyst. When the two catalysts comprise one or more organic compounds, these may be identical or different.

[0130] Preferably, the organic compound of the second catalyst contains oxygen, preferably it is chosen from γ-valerolactone, 2-acetylbutyrolactone, triethylene glycol, diethylene glycol, ethylene glycol, ethylenediaminetetraacetic acid (EDTA), maleic acid, malonic acid, citric acid, acetic acid, oxalic acid, gluconic acid, glucose, fructose, sucrose, sorbitol, xylitol, γ-ketovaleric acid, a C1-C4 dialkyl succinate and more particularly dimethyl succinate, dimethylformamide, 1-methyl-2-pyrrolidinone, propylene carbonate, 2-methoxyethyl 3-oxobutanoate, bicine, tricine, 2-furaldehyde (also known as name furfural), 5-hydroxymethylfurfural (also known as 5-(hydroxymethyl)-2-furaldehyde or 5-HMF), 2-acetylfuran, 5-methyl-2-furaldehyde, ascorbic acid, butyl lactate, ethyl lactate, butyl butyryllactate,ethyl 3-hydroxybutanoate, ethyl 3-ethoxypropanoate, 2-ethoxyethyl acetate, 2-butoxyethyl acetate, 2-hydroxyethyl acrylate, l-vinyl-2-pyrrolidinone, l,3-dimethyl-2-imidazolidinone, 1,5-pentanediol, l-(2-hydroxyethyl)-2-pyrrolidinone, l-(2-hydroxyethyl)-2,5-pyrrolidinedione, 5-methyl-2(3H)-furanone, l-methyl-2-piperidinone, 4-aminobutanoic acid, butyl glycolate, ethyl 2-mercaptopropanoate, ethyl 4-oxopentanoate, diethyl maleate, dimethyl maleate, fumarate dimethyl, diethyl fumarate, dimethyl adipate and dimethyl 3-oxoglutarate.

[0131] According to a preferred embodiment, the hydrotreatment process implements a sequence of a first hydrotreatment reaction section containing the first catalyst based on nickel and molybdenum in the presence of phosphorus and an organic compound on an alumina support and a second hydrotreatment reaction section containing the second catalyst based on nickel and tungsten in the presence of phosphorus and an organic compound on a silica-alumina support, said second catalyst being characterized by:

[0132] - the nickel content, expressed in the form of NiO, is between 1.3 and 4.3% by weight relative to the total weight of the catalyst, preferably between 1.4 and 3.8% by weight, and more preferably between 1.5 and 3.4% by weight,

[0133] - the tungsten content, expressed in the form WO3, is between 17 and 31% weight relative to the total weight of the catalyst, preferably between 18 and 30% by weight, preferably between 19 and 29% by weight, and more preferably between 20 and 26% by weight,

[0134] the phosphorus content, expressed in the form P2O5, is preferably between 1.3 and 3.4% by weight relative to the total weight of the catalyst, preferably between 1.4 and 3.1% by weight, and very preferably between 1.5 and 2.8% by weight.

[0135] - a Ni / W molar ratio of between 0.18 and 0.45 mol / mol, preferably between between 0.20 and 0.43 mol / mol and even more preferably between 0.22 and 0.42 mol / mol.

[0136] - a P / W molar ratio of between 0.18 and 0.45 mol / mol, preferably between between 0.20 and 0.43 mol / mol and even more preferably between 0.22 and 0.42 mol / mol.

[0137] According to this preferred embodiment, said first hydrotreatment reaction section containing the first catalyst occupies a volume VI, and said second hydrotreatment reaction section containing the second catalyst occupies a volume V2, the distribution of the volumes V1 / V2 being between 50% vol / 50% vol and 90% vol / 10% vol, preferably between 60% vol / 40% vol and 85% vol / 15% vol and particularly preferably between 70% vol / 30% vol and 80% vol / 20% vol, respectively of said first and second hydrotreatment reaction sections.

[0138] According to this embodiment, the organic compound is preferably chosen from γ-valerolactone, 2-acetylbutyrolactone, triethylene glycol, diethylene glycol, ethylene glycol, ethylenediaminetetraacetic acid (EDTA), maleic acid, malonic acid, citric acid, acetic acid, gluconic acid, glucose, fructose, sucrose, sorbitol, xylitol, γ-ketovaleric acid, a C1-C4 dialkyl succinate and more particularly dimethyl succinate, dimethylformamide, 1-methyl-2-pyrrolidinone, propylene carbonate, 2-methoxyethyl 3-oxobutanoate, bicine, tricine, 2-furaldehyde (also known as furfural), 5-hydroxymethylfurfural (also known under the name 5-(hydroxymethyl)-2-furaldehyde or 5-HMF), 2-acetylfuran, 5-methyl-2-furaldehyde, ascorbic acid, butyl lactate, ethyl lactate, butyl butyryllactate, ethyl 3-hydroxybutanoate, ethyl 3-ethoxypropanoate,2-ethoxyethyl acetate, 2-butoxyethyl acetate, 2-hydroxyethyl acrylate, l-vinyl-2-pyrrolidinone, l,3-dimethyl-2-imidazolidinone, 1,5-pentanediol, l-(2-hydroxyethyl)-2-pyrrolidinone, l-(2-hydroxyethyl)-2,5-pyrrolidinedione, 5-methyl-2(3H)-furanone, l-methyl-2-piperidinone, 4-aminobutanoic acid, butyl glycolate, ethyl 2-mercaptopropanoate, ethyl 4-oxopentanoate, diethyl maleate, dimethyl maleate, dimethyl fumarate, diethyl fumarate, dimethyl adipate and Dimethyl 3-oxoglutarate. , Preparation process

[0139] The first and second catalysts can be prepared according to any method of preparing a supported catalyst known to those skilled in the art.

[0140] The first and second catalysts can be prepared according to a preparation method comprising the following steps:

[0141] i) a nickel precursor, a molybdenum precursor or a tungsten precursor, phosphorus when present, and an organic compound when present are brought into contact with an alumina or silica-alumina-based support, so as to obtain a catalyst precursor,

[0142] ii) said catalyst precursor from step i) is dried at a temperature below 200°C,

[0143] iii) optionally, the catalyst precursor obtained in step ii) is calcined at a temperature between 200°C and 550°C,

[0144] iv) optionally, the catalyst obtained in step ii) or in step iii) is sulphurized.

[0145] During the contacting of step i), the first and second catalysts can be prepared by impregnation of the metals and phosphorus onto the selected support. The impregnation can for example be carried out according to the method known to those skilled in the art under the terminology of dry impregnation, in which just the quantity of desired elements is introduced in the form of salts soluble in the chosen solvent, for example demineralized water, so as to fill the porosity of the support as exactly as possible.

[0146] The precursors of the active phase can be introduced simultaneously or successively. The impregnation of each precursor can advantageously be carried out in at least two stages. The different precursors can thus advantageously be impregnated successively with a differentiated impregnation and maturation time. One of the precursors can also be impregnated in several stages.

[0147] Preferably, the precursors of the active phase are introduced simultaneously.

[0148] The nickel precursors which can be used are advantageously chosen from nickel oxides, hydroxides, hydroxycarbonates, carbonates and nitrates, for example, nickel hydroxycarbonate, carbonate or hydroxide are preferably used.

[0149] The molybdenum precursors that can be used are well known to those skilled in the art. For example, among the sources of molybdenum, it is possible to use oxides and hydroxides, molybdic acids and their salts, in particular ammonium salts such as ammonium molybdate, ammonium heptamolybdate, phosphomolybdic acid (H3PMoi2O40) and their salts, and possibly silicomolybdic acid (H4 SiMoi204o) and its salts. The sources of molybdenum can also be heteropoly compounds of the Keggin, lacunar Keggin, substituted Keggin, Dawson, Anderson, Strandberg type, for example. Molybdenum trioxide and hetero- Strandberg, Keggin, lacunar Keggin or substituted Keggin type polyanions.

[0150] The tungsten precursors that can be used are also well known to those skilled in the art. For example, among the sources of tungsten, it is possible to use oxides and hydroxides, tungstic acids and their salts, in particular ammonium salts such as ammonium tungstate, ammonium metatungstate, phosphotungstic acid and their salts, and possibly silicotungstic acid (H4SiWi204o) and its salts. The sources of tungsten can also be heteropolycompounds of the Keggin, vacated Keggin, substituted Keggin, Dawson type, for example. Preferably, ammonium oxides and salts such as ammonium metatungstate or heteropolyanions of the Keggin, vacated Keggin or substituted Keggin type are used.

[0151] The phosphorus may be introduced in whole or in part by impregnation. Preferably, it is introduced by impregnation, preferably dry, using a solution containing the precursors of nickel, molybdenum or tungsten.

[0152] Said phosphorus can advantageously be introduced alone or in a mixture with the active phase, and this during any of the steps of impregnation of the hydrogenating function if the latter is introduced in several times. Said phosphorus can also be introduced, all or part, during the impregnation of an organic compound containing oxygen and / or nitrogen and / or sulfur if the latter is introduced separately from the hydrogenating function (case of post- and pre-impregnation described later). It can also be introduced from the synthesis of the support, at any stage of the synthesis thereof. It can thus be introduced before, during or after the mixing of the chosen alumina gel matrix, such as for example and preferably aluminum oxyhydroxide (boehmite) precursor of alumina.

[0153] The preferred phosphorus precursor is orthophosphoric acid H3PO4, but its salts and esters such as ammonium phosphates are also suitable. Phosphorus may also be introduced together with the group VIB element(s) in the form of Keggin, vacated Keggin, substituted Keggin or Strandberg type heteropolyanions.

[0154] Any impregnation solution described in the present invention may comprise any polar solvent known to those skilled in the art. Said polar solvent used is advantageously chosen from the group formed by methanol, ethanol, water, phenol, cyclohexanol, taken alone or as a mixture. Preferably, a polar protic solvent is used. A list of common polar solvents as well as their dielectric constant can be found in the book “Solvents and Solvent Effects in Organic Chemistry”, C. Reichardt, Wiley-VCH, 3rd edition, 2003, pages 472-474. Very preferably, the solvent used is water or ethanol, and particularly preferably, the solvent is water. In one possible embodiment, the solvent may be absent in the impregnation solution.

[0155] When the first or second catalyst further comprises a dopant chosen from boron, fluorine or a mixture of boron and fluorine, the introduction of this (these) dopant(s) can be done in the same way as the introduction of phosphorus described above at various stages of the preparation and in various ways.

[0156] The boron precursors may be boric acid, orthoboric acid H3BO3, ammonium biborate or pentaborate, boron oxide, boric esters. Boron may be introduced for example by a boric acid solution in a water / alcohol mixture or in a water / ethanolamine mixture. Preferably the boron precursor, if boron is introduced, is orthoboric acid.

[0157] The fluorine precursors that 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 the hydrofluoric acid. The fluorine can be introduced, for example, by impregnation of an aqueous solution of hydrofluoric acid, or ammonium fluoride or ammonium bifluoride.

[0158] The organic compound containing oxygen and / or nitrogen and / or sulfur of the second catalyst, or of the first catalyst when present, is introduced before the drying step ii). The organic compound is generally introduced by impregnation, in the presence or absence of the active phase and phosphorus and in the presence or absence of a solvent.

[0159] The introduction of the organic compound comprises several methods of implementation which are distinguished in particular by the time of introduction of the organic compound in relation to the introduction of the metals. It can be carried out either at the same time as the impregnation of the metals (co-impregnation), or after the impregnation of the metals (post-impregnation), or finally before the impregnation of the metals (pre-impregnation) in particular during the preparation of the support, and preferably during the shaping or by impregnation on an already formed support. Each method, taken alone or in combination, can take place in one or more stages.

[0160] In addition, the contacting step may combine at least two implementation modes, for example co-impregnation and post-impregnation. According to an alternative embodiment, the contacting according to step i) combines at least two contacting modes, for example co-impregnation of the active phase and phosphorus with an organic compound, followed by drying at a temperature below 200°C, then post-impregnation of an organic compound which may be identical or different from that used for the co-impregnation. Each mode, taken alone or in com- combination, can take place in one or more stages.

[0161] The organic compound of the second catalyst and of the first catalyst when present is preferably introduced in post-impregnation. In this case, the metals and phosphorus are first introduced, dried at a temperature below 200°C, the organic compound is introduced, then dried at a temperature below 200°C without subsequent calcination.

[0162] The organic compound(s) is (are) advantageously introduced into an impregnation solution which, depending on the method of preparation, may be the same solution or a different solution from that containing the precursors of the active phase and the phosphorus, in a corresponding quantity:

[0163] - at a molar ratio of the organic compound to the sum of the element(s) of the group VIB of the catalyst precursors (Mo for the first catalyst or W for the second catalyst) between 0.01 and 5 mol / mol, preferably between 0.05 and 3 mol / mol, more preferably between 0.05 and 1.5 mol / mol and very preferably between 0.1 and 1.2 mol / mol, calculated on the basis of the components introduced into the impregnation solution(s), and

[0164] - at a molar ratio of the organic compound to nickel of between 0.02 and 17 mol / mol, preferably between 0.1 and 10 mol / mol, more preferably between 0.15 and 8 mol / mol and very preferably between 0.6 and 5 mol / mol, calculated on the basis of the components introduced into the impregnation solution(s).

[0165] When several organic compounds are present, the different molar ratios apply for each of the organic compounds present.

[0166] Advantageously, after each impregnation step, the impregnated support is allowed to mature. Maturation allows the impregnation solution to disperse homogeneously within the support.

[0167] Any maturation step described in the present invention is advantageously carried out at atmospheric pressure, in a water-saturated atmosphere and at a temperature between 17°C and 50°C, and preferably at room temperature. Generally, a maturation time of between ten minutes and forty-eight hours, and preferably between thirty minutes and five hours, is sufficient. Longer times are not excluded, but do not necessarily provide an improvement.

[0168] In accordance with step ii) of the preparation process according to the invention, the catalyst precursor obtained in step i) optionally matured is subjected to a drying step at a temperature below 200°C, preferably between 50 and 180°C, preferably between 70 and 150°C and very preferably between 75 and 130°C.

[0169] The drying step is advantageously carried out by any technique known to those skilled in the art. It is advantageously carried out at atmospheric pressure or at reduced pressure, and preferably at atmospheric pressure. It is advantageously carried out in a flow-through bed using air or any other hot gas. Preferably, when the drying is carried out in a fixed bed, the gas used is either air or an inert gas such as argon or nitrogen. Very preferably, the drying is carried out in a flow-through bed in the presence of nitrogen and / or air. Preferably, the drying step has a short duration of between 5 minutes and 4 hours, preferably between 30 minutes and 4 hours and very preferably between 1 hour and 3 hours. When an organic compound is present, the drying is then carried out so as to preferably retain at least 30% of the organic compound introduced, preferably this quantity is greater than 50% and even more preferably, greater than 70%, calculated on the basis of the carbon remaining on the catalyst. At the end of drying step b), a dried catalyst is obtained.

[0170] Optionally, the drying step ii) may be followed by a calcination step iii).

[0171] According to this variant, at the end of drying step ii), a calcination step c) is carried out at a temperature between 200°C and 600°C, preferably between 250°C and 550°C, under an inert atmosphere (nitrogen for example) or under an atmosphere containing oxygen (air for example). The duration of this heat treatment is generally between 0.5 hours and 16 hours, preferably between 1 hour and 5 hours. After this treatment, the active phase is thus in oxide form, the heteropolyanions are thus transformed into oxides. Similarly, the catalyst no longer contains or contains very little organic compound when it was introduced. However, the introduction of the organic compound during its preparation made it possible to increase the dispersion of the active phase, thus leading to a more active catalyst.

[0172] When an organic compound is present, the catalyst is preferably not subjected to calcination. Calcination is understood here to mean a heat treatment under a gas containing air or oxygen at a temperature greater than or equal to 200°C.

[0173] However, the catalyst precursor may undergo a calcination step before the introduction of the organic compound, in particular after the impregnation of the active phase, and of the phosphorus.

[0174] The first or second catalyst may be a fresh catalyst, i.e. a catalyst which has not been used as a catalyst previously in a catalytic unit and in particular in hydrotreatment.

[0175] The first or second catalyst according to the invention may also be a regenerated and / or rejuvenated catalyst. A regenerated and / or rejuvenated catalyst is understood to mean a catalyst which has been used as a catalyst in a catalytic unit and in particular in hydrotreatment and / or hydrocracking and which has been subjected to at least one step partial or total removal of coke, for example by calcination (regeneration). Regeneration can be carried out by any means known to those skilled in the art. Regeneration is generally carried out by calcination at temperatures between 350 and 550°C, and most often between 400 and 520°C, or between 420 and 520°C, or between 450 and 520°C, temperatures below 500°C often being advantageous.

[0176] When the regenerated catalyst no longer comprises enough active phase, phosphorus or when it has a ratio or ratios outside the preferred ratios described above, the regenerated catalyst can be rejuvenated by introducing one or more precursors of the active phase and / or phosphorus into the regenerated catalyst. It is also possible to introduce at least one organic compound simultaneously with the metals and phosphorus or separately.The organic compound introduced may or may not be identical to the organic compound of the fresh catalyst when this catalyst contained such an organic compound. The operating conditions described above concerning maturation, drying and optional calcination and optional sulfurization are of course applicable within the framework of this latter embodiment.

[0177] Before its use for the hydrotreatment reaction, it is advantageous to transform the first and / or the second catalysts into a sulfurized catalyst in order to form its active species. This activation or sulfurization step is carried out by methods well known to those skilled in the art, and advantageously under a sulfide-reducing atmosphere in the presence of hydrogen and hydrogen sulfide.

[0178] According to a variant, the first or second catalyst is advantageously subjected to a sulfurization step after ii) drying or step iii) optional calcination.

[0179] Said catalyst is advantageously sulfurized ex situ or in situ. The sulfurizing agents are H2S gas, elemental sulfur, CS2, mercaptans, sulfides and / or polysulfides, hydrocarbon fractions with a boiling point below 400°C containing sulfur compounds or any other compound containing sulfur used for the activation of hydrocarbon feedstocks in order to sulfurize the catalyst. Said sulfur-containing compounds are advantageously chosen from alkyl disulfides such as, for example, dimethyl disulfide (DMDS), alkyl sulfides, such as, for example, dimethyl sulfide, thiols such as, for example, n-butyl mercaptan (or 1-butanethiol) and polysulfide compounds of the tert-onylpolysulfide type. The catalyst can also be sulfurized by the sulfur contained in the feedstock to be desulfurized. Preferably, the catalyst is sulfurized in situ in the presence of a sulfurizing agent and a hydrocarbon feedstock.Very preferably, the catalyst is sulfurized in situ in the presence of a hydrocarbon feedstock with added dimethyl disulfide.

[0180] Application of the process according to the invention in a hydrocracking process

[0181] According to a first variant, the hydrotreatment process according to the invention is advantageously tageously implemented as pretreatment in a hydrocracking process, and more particularly in a so-called "one-step" hydrocracking process or in a so-called "two-step" hydrocracking process. The hydrocracking process makes it possible to convert petroleum fractions, in particular vacuum distillates (VDS) into lighter and more valuable products (gasoline, middle distillates). The hydrotreatment process according to the invention aims to eliminate the sulfur, nitrogen or aromatic compounds present in said vacuum distillate cut.

[0182] A so-called "one-step" hydrocracking process generally comprises, firstly and generally, an advanced hydrotreatment which aims to carry out an advanced HDN, HDS and HDA of the feedstock before it is sent to the hydrocracking catalyst(s). Said one-step hydrocracking process is particularly advantageous when said hydrocracking catalyst(s) comprise(s) a support comprising zeolite crystals. This advanced hydrotreatment of the feedstock only results in a limited conversion of the feedstock into lighter fractions, which remains insufficient and must therefore be completed on the more active hydrocracking catalyst(s).However, it should be noted that no separation of the effluents occurs between the different catalytic beds: the entire effluent leaving the hydrotreatment catalytic bed is injected onto the catalytic bed(s) containing said hydrocracking catalyst(s) and then a separation of the products formed is carried out. This version of hydrocracking has a variant which presents a recycling of the unconverted fraction to at least one of the hydrocracking catalytic beds for a more advanced conversion of the feedstock. Advantageously, the hydrotreatment process according to the invention comprising the specific sequence according to the invention is implemented upstream of a hydrocracking catalyst in a one-stage hydrocracking process. It also makes it possible to limit the nitrogen content at the end of the pretreatment step in order to protect the zeolite-based hydrocracking catalyst which is very sensitive to nitrogen.

[0183] A so-called "two-stage" hydrocracking process comprises a first stage which has the objective, as in the "one-stage" process, of carrying out the hydrotreatment of the feedstock, but also of achieving a conversion of the latter of the order of generally 40 to 60%. The effluent from the first stage then undergoes a separation, generally by distillation, most often called intermediate separation, which has the objective of separating the conversion products from the unconverted fraction. In the second stage of the two-stage hydrocracking process according to the invention, only the fraction of the feedstock not converted during the first stage is treated. This separation allows the two-stage hydrocracking process according to the invention to be more selective in middle distillate (kerosene + diesel) than the one-stage process according to the invention. Indeed, the intermediate separation of the conversion products prevents their ''over-cracking'' into naphtha and gas in the second stage on the hydrocracking catalyst(s). Furthermore, it should be noted that the unconverted fraction of the feedstock treated in the second stage generally contains very low levels of NH3 as well as organic nitrogen compounds, generally less than 20 ppm by weight or even less than 10 ppm by weight.

[0184] Said first step is carried out in the presence of the specific sequence of catalysts according to the invention, and of a hydrocracking catalyst in order to carry out a hydrotreatment and a conversion of the order generally of 40 to 60%. The catalytic beds of the specific sequence of catalysts according to the invention are advantageously located upstream of the hydrocracking catalyst. Said second step is generally carried out in the presence of a hydrocracking catalyst of composition different from that present for the implementation of said first step.

[0185] The hydrocracking processes are generally carried out at a temperature of between 250 and 480°C, advantageously between 320 and 450°C, preferably between 330 and 435°C, under a pressure of between 2 and 25 MPa, preferably between 3 and 20 MPa, the hourly volumetric flow rate of the feedstock relative to the volume of each catalyst (WH) is advantageously between 0.1 and 40 h1, preferably between 0.2 and 12 h1, very preferably between 0.4 and 6 h 1 and the hydrogen / feedstock ratio expressed in normal cubic meters (Nm3) of hydrogen per cubic meter (m3) of hydrocarbon feedstock is advantageously between 80 NL / L to 5000 NL / L, preferably between 100 and 2000 NL / L. Vacuum distillate hydrocracking processes cover pressure and conversion ranges from mild to high pressure hydrocracking.Mild hydrocracking is defined as hydrocracking leading to moderate conversions, generally less than 40%, and operating at low pressure, generally between 2 MPa and 6 MPa.

[0186] Hydrocracking catalysts are of the bifunctional type: they combine an acid function with a hydro-dehydrogenating function. The acid function is provided by porous supports whose surface areas generally vary from 150 to 800 m2.g 1 and having a surface acidity, such as halogenated aluminas (chlorinated or fluorinated in particular), combinations of boron and aluminum oxides, amorphous or crystalline mesoporous alumino-silicates and zeolites dispersed in an oxide binder. The hydro-dehydrogenating function is provided by the presence of an active phase based on at least one metal from group VIB and possibly at least one metal from group VIII of the periodic table of elements. The most common formulations are of the nickel-molybdenum (NiMo) and nickel-tungsten (NiW) type and more rarely of the cobalt-molybdenum (CoMo) type. After preparation, the hydro-dehydrogenating function often appears in the form of oxide.The usual methods leading to the . formation of the hydro-dehydrogenating phase of hydrocracking catalysts consists of a deposition of molecular precursor(s) of at least one metal from group VIB and possibly at least one metal from group VIII on an acid oxide support by the technique called "dry impregnation" followed by maturation, drying and calcination steps leading to the formation of the oxidized form of said metal(s) used. The active and stable form for hydrocracking processes being the sulfurized form, these catalysts must undergo a sulfurization step. This can be carried out in the associated process unit (this is called in-situ sulfurization) or prior to loading the catalyst into the unit (this is called ex-situ sulfurization).

[0187] Application of the method according to the invention in an FCC method

[0188] According to a second variant, the hydrotreatment process according to the invention is advantageously implemented as pretreatment in a fluidized bed catalytic cracking process (or FCC process for Fluid Catalytic Cracking according to the English terminology). The FCC process can be carried out in a conventional manner known to those skilled in the art under suitable cracking conditions in order to produce hydrocarbon products of lower molecular weight. For example, a summary description of catalytic cracking (the first industrial implementation of which dates back to 1936 (HOUDRY process) or to 1942 for the use of a fluidized bed catalyst) can be found in ULLMANS ENCYCLOPEDIA OF INDUSTRIAL CHEMISTRY VOLUME A 18, 1991, pages 61 to 64.

[0189] A conventional catalyst comprising a matrix, optionally an additive and at least one zeolite is usually used in the FCC process. The amount of zeolite is variable but usually from 3 to 60% by weight, often from 6 to 50% by weight and most often from 10 to 45% by weight relative to the weight of the catalyst. The zeolite is usually dispersed in the matrix. The amount of additive is usually from 0 to 30% by weight and often from 0 to 20% by weight relative to the weight of the catalyst. The amount of matrix represents the balance to 100% by weight. The additive is generally chosen from the group formed by the oxides of the metals of group IIA of the periodic table of elements such as for example magnesium oxide or calcium oxide, the oxides of the rare earths and the titanates of the metals of group IIA.The matrix is ​​most often silica, alumina, silica-alumina, silica-magnesia, clay or a mixture of two or more of these products. The most commonly used zeolite is zeolite Y.

[0190] Cracking is carried out in a substantially vertical reactor either in ascending mode (riser) or descending mode (dropper). The choice of catalyst and operating conditions depend on the desired products depending on the feedstock treated, as described, for example, in the article by M. MARCILLY pages 990-991 published in the journal of the French Petroleum Institute Nov.-Dec. 1975 pages 969-1006. The operation is usually carried out at a temperature of 450 to 600°C and residence times in the reactor are less than 1 minute, often from 0.1 to 50 seconds.

[0191] The pretreatment also makes it possible to limit the nitrogen content at the end of the pretreatment step in order to protect the zeolite-based catalytic cracking catalyst which is very sensitive to nitrogen. EXAMPLES

[0192] The following examples demonstrate the significant gain in activity in HDA and HDN using the specific sequence according to the invention.

[0193] Examples 1 to 3 describe the preparation of catalysts C1 to C3. The final composition of each catalyst in metals and phosphorus, expressed in the form of oxides and relative to the weight of the catalyst, as well as the Ni / W and P / W ratios are shown in Table 1 below.

[0194] Examples 4 to 8 describe the evaluation in hydrodenitrogenation (HDN) and in hydrogenation of aromatics (HDA) of vacuum distillate of the different catalysts and / or catalyst chains C1, C2 and C3.

[0195] Example 1: Preparation of the NiMoP catalyst on Cl alumina

[0196] On 100 grams of an alumina Al support having a loss on ignition of 4.1% by weight, a BET surface area of ​​263 m2 / g, a pore volume measured by mercury porosimetry of 0.66 ml / g and an average pore diameter of 9.7 nm defined as the median diameter by volume by mercury porosimetry and which is in the “extruded” form, nickel, molybdenum, and phosphorus are added. The Al support has a water uptake volume of 0.72 mL / g. The impregnation solution is prepared by dissolving at 90°C 32.9 grams of molybdenum oxide (Merck™, purity > 99.5% wt.), 10.5 grams of nickel hydroxycarbonate (Merck™, purity 99.9% wt.) and 12.78 grams of orthophosphoric acid solution (Merck™, 85% wt. in water) in 53.7 mL of distilled water. After dry impregnation, the extrudates are left to mature in a water-saturated atmosphere for 24 h at room temperature, then they are dried at 90°C for 16 h.The dried impregnated support of the Cl catalyst is then added by dry impregnation of a solution containing a mixture of dimethyl succinate (DMSU) and acetic acid (75% purity). The molar ratios are as follows: DMSU / Mo = 0.85 mol / mol, DMSU / acetic acid = 0.5 mol / mol. The catalyst undergoes a further maturation step of 3 h at 20°C in air and then drying in a traversed bed type oven at 120°C for 3 h. The dried catalyst thus obtained is denoted CL. The final composition of the Cl catalyst expressed in the form of oxides is then as follows: MoO3 = 22 + / - 0.2 (% by weight), NiO = 4.5 + / - 0.1 (% by weight) and P2O5 = 5.3 +- 0.1 (% by weight).

[0197] Example 2: Preparation of the NiWP catalyst on silica-alumina C2

[0198] On 100 grams of an amorphous silica-alumina support ASA1 having a loss on ignition of 1.5% by weight, a BET surface area of ​​240 m2 / g, a pore volume measured by mercury porosimetry of 0.46 ml / g and an average pore diameter of 7.42 nm defined as the median diameter by volume by mercury porosimetry and which is in the “extruded” form, nickel, tungsten and phosphorus are added. The ASA1 support has a water uptake volume of 0.56 mL / g. The impregnation solution is prepared by dissolving at 80°C 43.93 g of phospho-tungstic acid hydrate (Merck™, purity >99.5% wt), 2.97 g of phosphoric acid (Merck™, 85% wt in water), 7.26 g of nickel hydroxycarbonate (Merck™, purity 99.9% wt) in 48.1 mL of distilled water. After dry impregnation, the extrudates are left to mature in a water-saturated atmosphere for 24 h at room temperature, then they are dried at 120°C for 5 hours.

[0199] The dried impregnated support of catalyst C2 is then added by dry impregnation of a solution containing an aqueous solution of γ-ketovaleric acid. The molar ratio is as follows: γ-ketovaleric acid AV = 0.8 mol / mol. The catalyst further undergoes a maturation step of 3 h at 20°C in air then drying in a traversed bed type oven at 120°C for 3 h. The dried catalyst thus obtained is denoted C2.

[0200] The final composition of catalyst C2 expressed in the form of oxides is then as follows: WO3 = 25 + / - 0.2 (% by weight), NiO = 3.22 + / - 0.1 (% by weight) and P2O5 = 1.91 + / - 0.1 (% by weight).

[0201] Example 3: Preparation of NiWP catalyst on C3 alumina

[0202] On the same Al support as presented in Example 1, nickel, tungsten and phosphorus are added. The impregnation solution is prepared by dissolving at 80°C 48.18 g of hydrated phosphotungstic acid (Merck™, purity >99.5% by weight), 3.32 g of phosphoric acid (Merck™, 85% by weight in water), 8.12 g of nickel hydroxycarbonate (Merck™, purity 99.9% by weight) in 69.4 mL of distilled water. After dry impregnation of 100 g of the Al support, the extrudates are left to mature in a water-saturated atmosphere for 24 h at room temperature, then they are dried at 120°C for 5 hours.

[0203] The dried impregnated support of catalyst C3 is then added by dry impregnation of a solution containing an aqueous solution of γ-ketovaleric acid. The molar ratio is as follows: γ-ketovaleric acid AV = 0.8 mol / mol. The catalyst further undergoes a maturation step of 3 h at 20°C in air then drying in a traversed bed type oven at 120°C for 3 h. The dried catalyst thus obtained is denoted C3.

[0204] The final composition of catalyst C3 expressed in the form of oxides is then as follows: WO3 = 27 + / - 0.2 (% by weight), NiO = 3.48 + / - 0.1 (% by weight) and P2O5 = 2.07 +- 0.1 (% by weight).

[0205] [Tables 1] Catalyst % wt NiO % wt MoO3 % wt WO3 % wt p2o5 Ni / W (mol / mol) P / W (mol / mol) Cl 4.5 22 - 5.3 0.38 0.46 C2 3.22 25 1.91 0.4 0.25 C3 3.48 27 2.07 0.4 0.25

[0206] Table 1: Composition of catalysts C1, C2 and C3.

[0207] Examples 4 to 7: Evaluation in hydrodenitrogenation (HDN) and hydrogenation of aromatics (HDA) of vacuum distillates of catalysts or chains of catalysts Cl, C2 and C3

[0208] The catalysts and / or catalyst chains taken from among the catalysts C1, C2, C3 were tested in hydrodenitrogenation (HDN) and hydrogenation of aromatics (HDA) of vacuum distillates.

[0209] The feedstock is a vacuum distillate (light vacuum gas oil in English terminology) from deep hydroconversion of vacuum residues using the H-Oil™ process. The characteristics of the test feedstock used are as follows: density at 15°C = 0.92 g / cm3 (NF EN ISO 12185), refractive index at 20°C = 1.5122 (ASTM D1218-12), sulfur content = 0.59% by weight, nitrogen content = 2720 ppm by weight.

[0210] • Simulated Distillation (ASTM D2887):

[0211] - PI: 240.7 °C;

[0212] - 10%: 331.5 °C;

[0213] - 50%: 424.9 °C;

[0214] - 90%: 539.4 °C;

[0215] -PF: 600.9 °C.

[0216] The test is carried out in an isothermal fixed-bed pilot reactor, with fluids circulating from bottom to top. The reactor comprises two catalytic zones allowing different sequences of catalysts C1, C2 and C3 to be evaluated. The feed first passes through the first zone loaded with the first catalyst, then the second zone loaded with the second catalyst.

[0217] According to example 4 (in accordance with the invention), the first zone is loaded with catalyst C1 (70% of the volume), then the second with catalyst C2 (30% of the volume).

[0218] According to example 5 (in accordance with the invention), the first zone is loaded with catalyst C1 (50% of the volume), then the second with catalyst C2 (50% of the volume).

[0219] According to example 6 (not in accordance with the invention), the two zones are loaded with catalyst Cl (100% of the volume)

[0220] According to example 7 (not in accordance with the invention), the two zones are loaded with catalyst C2 (100% of the volume).

[0221] According to example 8 (not in accordance with the invention), the first zone is loaded with catalyst C1 (70% of the volume), then the second with catalyst C3 (30% of the volume).

[0222] The catalysts are previously sulfurized in situ at 350°C in the pressurized reactor using an atmospheric distillation gas oil feedstock (straight run according to English terminology) (density at 15°C = 0.8491 g / cm3 (NF EN ISO 12185) and initial sulfur content = 0.42% by weight), to which 2% by weight of dimethyl disulfide is added.

[0223] The catalytic tests were conducted under the following operating conditions: a total pressure of 14 MPa, a total volume of the two catalytic zones of 9 cm3, a temperature between 390°C and 415°C, with a hydrogen flow rate of 15.8 L / h and with a charge flow rate of 14.4 cm3 / h.

[0224] The characteristics of the effluents are analyzed: density at 15 °C (NF EN ISO 12185), refractive index at 20 °C (ASTM D1218-12), simulated distillation (ASTM D2887), sulfur content and nitrogen content. The residual aromatic carbon contents are calculated by the ndM method (ASTM D3238). The hydrogenation rate of the aromatics is calculated as the ratio of the aromatic carbon content in the feedstock to which that of the effluents is subtracted, to that of the test feedstock. The hydrodenitrogenation rate is calculated as the ratio of the nitrogen content of the effluents to which that of the effluents is subtracted, to that of the test feedstock.

[0225] The catalytic performances of the catalyst chains tested are given in Table 2. They are expressed in relative volume activity (RVA) relative to 100% vol catalyst Cl chosen as reference (example 6), assuming an order of 1.2 for the HDA reaction and an order of 1 for the HDN reaction.

[0226] Table 2 clearly shows the gain in catalytic effect provided by the specific sequences according to the invention. Indeed, the catalyst sequences according to the invention make it possible to significantly increase the volume activities in the hydrodearomatization (HDA) and hydrodenitrogenation (HDN) reactions of vacuum distillates.

[0227] [Tables2] Example Catalyst loading in the reactor (first zone / second zone) RVA HDN RVA HDA 4 (according to the invention) 70% vol catalyst Cl + 30% vol catalyst C2 104 105 5 (according to the invention) 50% vol catalyst Cl + 50% vol catalyst C2 104 107 6 (non-compliant) 100% vol catalyst Cl 100 100 7 (non-compliant) 100% vol catalyst C2 72 95 8 (non-compliant) 70% vol catalyst Cl + 30% vol catalyst C3 90 101

[0228] Table 2: Relative HDA and HDN activities for the specific sequences according to the invention (examples 4 and 5) and non-compliant (examples 6 to 8).

Claims

Claims

1. A process for hydrotreating a hydrocarbon feedstock of which at least 50% by weight of the compounds have an initial boiling point above 300°C and a final boiling point below 650°C, at a temperature between 180°C and 450°C, a pressure between 0.5 and 30 MPa, an hourly volumetric flow rate between 0.1 and 20 h 1 and a hydrogen / feedstock ratio expressed in volume of hydrogen, measured under standard temperature and pressure conditions, per volume of liquid feedstock of between 50 L / L and 5000 L / L, so as to obtain a hydrotreated effluent, said process comprising the following steps: a) a first hydrotreatment step carried out in a first hydrotreatment reaction section, using at least one catalytic bed comprising at least one first hydrotreatment catalyst, said hydrotreatment reaction section being fed with at least said hydrocarbon feedstock and a gas stream comprising hydrogen, said first catalyst comprising an alumina support, an active phase consisting of nickel and molybdenum, and optionally phosphorus and / or optionally an organic compound containing oxygen and / or nitrogen and / or sulfur, b) a second hydrotreatment step carried out in a second hydrotreatment reaction section, using at least one catalytic bed comprising at least one second hydrotreatment catalyst, said hydrotreatment reaction section being fed with at least part of the effluent obtained in step a), said second catalyst comprising a silica-alumina support, an active phase consisting of nickel and tungsten, phosphorus, and an organic compound containing oxygen and / or nitrogen and / or sulfur.

2. A hydrotreatment process according to claim 1, wherein said first hydrotreatment reaction section containing the first catalyst occupies a volume VI, and said second hydrotreatment reaction section containing the second catalyst occupies a volume V2, the distribution of volumes V1 / V2 being between 50%vol / 50%vol and 90%vol / 10%vol respectively of said first and second hydrotreatment reaction sections.

3. Hydrotreatment process according to claim 2, wherein the volume distribution V1 / V2 is between 70%vol / 30%vol and 80%vol / 20%vol respectively of said first and second hydrotreatment reaction section.

4. Hydrotreatment process according to one of the preceding claims, in which the second catalyst is characterized in that: - the nickel content, expressed in the form of NiO, is between 1.2 and 4.5% by weight relative to the total weight of the catalyst, - the tungsten content, expressed in the form of WO3, is between 16 and 33% by weight relative to the total weight of the catalyst, - the phosphorus content, expressed in the form of P2O5, is between 1 and 4% by weight relative to the total weight of the catalyst.

5. Hydrotreatment process according to the preceding claim, in which the second catalyst is characterized in that: - the nickel content, expressed in the form of NiO, is between 1.3 and 4.3% by weight relative to the total weight of the catalyst, - the tungsten content, expressed in the form of WO3, is between 17 and 31% by weight relative to the total weight of the catalyst, - the phosphorus content, expressed in the form of P2O5, is preferably between 1.3 and 3.4% by weight relative to the total weight of the catalyst.

6. Hydrotreatment process according to claim 5, wherein the second catalyst is further characterized in that: - the Ni / W molar ratio is between 0.18 and 0.45 mol / mol, - the P / W molar ratio is between 0.18 and 0.45 mol / mol.

7. Hydrotreatment process according to one of the preceding claims, in which the silica content in the support of the second catalyst is between 10 and 50% by weight relative to the total weight of the support.

8. Hydrotreatment process according to one of the preceding claims, in which the first catalyst has a molybdenum content of between 5 and 40% by weight, expressed as MoO3, relative to the total weight of the catalyst and a nickel content of between 1 and 10% by weight, expressed as NiO, relative to the total weight of the catalyst.

9. Hydrotreatment process according to one of the preceding claims, in which the first catalyst further comprises phosphorus at a content of between 0.1 and 20% by weight expressed as P2O5 relative to the total weight of the catalyst.

10. Hydrotreatment process according to one of the preceding claims, wherein the first catalyst further contains an organic compound containing oxygen and / or nitrogen and / or sulfur.

11. Hydrotreatment process according to one of the preceding claims, in which the organic compound is chosen from a compound comprising one or more chemical functions chosen from a carboxylic function, alcohol, thiol, thioether, sulfone, sulfoxide, ether, aldehyde, ketone, ester, carbonate, amine, nitrile, imide, oxime, urea, amide or even compounds including a furan cycle or even a sugar.

12. A hydrotreatment process according to claim 11, wherein the organic compound is selected from γ-valerolactone, 2-acetylbutyrolactone, triethylene glycol, diethylene glycol, ethylene glycol, ethylenediaminetetraacetic acid (EDTA), maleic acid, malonic acid, citric acid, acetic acid, oxalic acid, gluconic acid, glucose, fructose, sucrose, sorbitol, xylitol, γ-ketovaleric acid, a C1-C4 dialkyl succinate and more particularly dimethyl succinate, dimethylformamide, 1-methyl-2-pyrrolidinone, propylene carbonate, 2-methoxyethyl 3-oxobutanoate, bicine, tricine, 2-furaldehyde (also known as the name furfural), 5-hydroxymethylfurfural, 2-acetylfuran, 5-methyl-2-furaldehyde, ascorbic acid, butyl lactate, ethyl lactate, butyl buty-ryllactate, ethyl 3-hydroxybutanoate, ethyl 3-ethoxypropanoate,2-ethoxyethyl acetate, 2-butoxyethyl acetate, 2-hydroxyethyl acrylate, l-vinyl-2-pyrrolidinone, l,3-dimethyl-2-imidazolidinone, 1,5-pentanediol, l-(2-hydroxyethyl)-2-pyrrolidinone, l-(2-hydroxyethyl)-2,5-pyrrolidinedione, 5-methyl-2(3H)-furanone, l-methyl-2-piperidinone, 4-aminobutanoic acid, butyl glycolate, ethyl 2-mercaptopropanoate, ethyl 4-oxopentanoate, diethyl maleate, dimethyl maleate, dimethyl fumarate, diethyl fumarate, dimethyl adipate and Dimethyl 3-oxoglutarate.,

13. Hydrotreatment process according to one of claims 10 to 12, in which the content of organic compound is between 1 and 30% by weight relative to the total weight of the catalyst.

14. Hydrotreatment process according to one of the preceding claims, in which the first and / or the second catalyst is at least par- partially sulfurized.

15. Hydrotreatment process according to one of the preceding claims, which is carried out as pretreatment in a fluidized bed catalytic cracking process.

16. Hydrotreatment process according to one of the preceding claims, which is carried out as pretreatment in a hydrocracking process.