Hydrotreatment process using catalyst sequence with catalyst based on nickel and tungsten on silica-alumina support

Abstract

The subject of the invention is a process for hydrotreating a hydrocarbon feedstock in which at least 50% by weight of the compounds have an initial boiling point greater than 300 DEG C and a final boiling point less than 650 DEG C, to obtain a hydrotreated effluent, comprising the following stages: a) contacting the hydrocarbon feedstock with at least one first catalyst in the presence of hydrogen, the invention relates to a method for producing an effluent from a first catalyst comprising an alumina support and an active phase consisting of nickel and molybdenum, b) contacting the effluent obtained in stage a) in the presence of hydrogen with at least one second catalyst comprising a silica-alumina support and an active phase consisting of nickel and tungsten, phosphorus and organic compounds.

Description

Technical Field

[0001] The present invention relates to a process for the hydrotreatment of hydrocarbon feedstocks using a sequence of at least two specific catalysts. The purpose of the process is to produce hydrodesulfurized, hydrodenitrogenated and / or hydrodearomatized feedstocks.

[0002] Conventional hydroprocessing catalysts usually comprise an oxide support and an active phase based on Group VIb and VIII metals (in oxide form) and phosphorus. The preparation of these catalysts usually comprises a stage in which the metals and phosphorus are impregnated on the support, followed by drying and calcining, so that the active phase in oxide form can be obtained. Before being used in hydroprocessing and / or hydrocracking reactions, these catalysts are usually sulfided to form active entities.

[0003] Those skilled in the art have suggested adding organic compounds to hydroprocessing catalysts to improve their activity, particularly for catalysts prepared by impregnation followed by drying without subsequent calcination. These catalysts are often referred to as "additive impregnated dried catalysts".

[0004] Typically, the purpose of hydrocarbon fraction hydrotreating catalysts is to remove sulfur-based, nitrogen-based or aromatic compounds contained in the hydrocarbon fraction, for example, in order to produce a petroleum product meeting the required specifications (sulfur content, aromatics content, etc.) for a given application (motor vehicle fuel, gasoline or gas oil, household heating oil, jet fuel).

[0005] Due to increasingly stringent legislation on air quality in many countries, efforts are ongoing to develop more efficient catalysts and processes for producing ultra-low sulfur fuels. Although much progress has been made in developing efficient catalysts for these processes, significant challenges remain, such as their modest activity for aromatic saturation or hydrodenitrogenation.

[0006] Therefore, in the field of pretreatment of hydrocracking processes or fluidized catalytic cracking processes (or FCC (fluid catalytic cracking) processes), there is a need to reduce the sulfur, nitrogen and aromatics content in order to improve the performance quality of the subsequent hydrocracking or FCC stage. These processes usually process feedstocks rich in sulfur, nitrogen and aromatics.

[0007] However, a hydroprocessing catalyst optimized for hydrodesulfurization (HDS) is not automatically optimized for aromatic saturation (or hydrodearomatization HDA) or hydrodenitrogenation (HDN), and vice versa. Therefore, it is often necessary to resort to catalyst sequences, where each catalyst is optimized for one hydroprocessing type.

[0008] Such supported catalyst sequences are described, for example, in documents US 2011 / 0079542, US Pat. No. 5,068,025, CN 1176290, FR 3013720 or FR 3013721.

[0009] There are also non-supported catalyst sequences, also called "bulk" catalysts, known, for example, from documents US Pat. No. 7,816,299 or CN 102,851,070. However, supported catalyst sequences have the advantage of using regenerable catalysts that are not only less expensive (because they contain less metal) but are also active at lower metal contents.

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

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

[0012] Regardless of the catalyst sequence chosen, the modifications made are not always sufficient to improve the performance qualities of the catalytic system to meet the specifications regarding the sulfur, nitrogen and / or aromatics content of the fuel. It is therefore of vital importance for refiners to find new hydroprocessing processes with improved performance qualities in terms of activity and stability.

[0013] The Applicant Company has developed a process for the hydrotreatment of hydrocarbon feedstocks consisting in contacting said feedstocks with a specific sequence of catalysts making it possible to increase the overall activity and the overall stability of the process.

[0014] Overview

[0015] The present invention relates to a method for hydrotreating a hydrocarbon feedstock to obtain a hydrotreating effluent, wherein at least 50% by weight of the compounds in the hydrocarbon feedstock have an initial boiling point greater than 300°C and a final boiling point less than 650°C, the temperature of the method is 180°C to 450°C, the pressure is 0.5 to 30 MPa, and the hourly space velocity is 0.1 to 20 h -1 , the hydrogen / feedstock ratio (expressed as the volume of hydrogen / liquid feedstock measured under standard temperature and pressure conditions) is 50 Sl / l to 5000 Sl / l, the method comprising the following stages:

[0016] a) a first hydrotreatment stage, 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,

[0017] b) a second hydrotreatment stage, 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 stage a), said second catalyst comprising a silica-alumina support, an active phase composed of nickel and tungsten, phosphorus and an organic compound containing oxygen and / or nitrogen and / or sulphur.

[0018] The Applicant Company surprisingly found that the sequence of a first hydrotreatment reaction stage comprising a first catalyst based on an active phase consisting of nickel and molybdenum on an alumina support and a second hydrotreatment reaction stage comprising 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, exhibits a synergistic effect in terms of activity and stability in hydrotreatment, in particular in the hydrogenation of aromatics (HDA), but also in hydrodenitrogenation (HDN) and / or hydrodesulfurization (HDS).

[0019] This is because, by choosing for each catalyst the correct active phase, a suitable support, the presence of phosphorus and / or organic compounds, a symbiosis can be observed with a first catalyst, followed by a second catalyst, making it possible to modify the structure of the most recalcitrant aromatics (through isomerization and / or cracking reactions), making these molecules more reactive and thus promoting the HDA required to increase the HDN, in particular through tungsten, which contributes to an increase in the hydrogenation activity, wherein the first catalyst is based on an active phase composed of nickel and molybdenum on a non-acidic or low-acidic support (alumina), in particular carrying out HDS and partial HDN, and the second catalyst is based on an active phase composed of nickel and tungsten on a more acidic support (silica-alumina) in the presence of phosphorus and organic compounds.

[0020] On the one hand, the second catalyst exhibits extremely high activity, especially in HDA and HDN, which makes it possible to supplement the hydroprocessing reactions of the first catalyst, especially HDS and HDN, which are necessary to achieve the specifications. Likewise, stability is improved because the cycle time is extended by reducing the temperature required to carry out the HDS, HDN and HDA reactions.

[0021] On the other hand, the second catalyst has a slower deactivation rate, which makes it more possible to increase the cycle time for standard feedstocks, or to process feedstocks rich in sulfur, nitrogen and / or aromatics.

[0022] The hydrotreatment process according to the invention is particularly suitable for use with vacuum distillate feedstocks.The hydrotreatment process according to the invention is also particularly suitable for use with hydrotreatment of feedstocks containing high contents of nitrogen and aromatics, such as feedstocks resulting from catalytic cracking, coking or visbreaking.

[0023] The process according to the invention makes it possible to produce a hydrotreated hydrocarbon fraction, i.e. a fraction that is simultaneously free of nitrogen-based compounds, sulfur-based compounds and most aromatic compounds. Preferably, according to the process according to the invention, the hydrodesulfurization (HDS) conversion is greater than 95%, preferably greater than 98%. Preferably, according to the process according to the invention, the hydrodenitrogenation (HDN) conversion is greater than 90%, preferably greater than 95%. Preferably, according to the process according to the invention, the aromatics hydrogenation (HDA) conversion is greater than 35%, preferably greater than 40%.

[0024] According to an alternative form, said first hydroprocessing reaction section comprising a first catalyst occupies a volume V1 and said second hydroprocessing reaction section comprising a second catalyst occupies a volume V2, with a volume distribution V1 / V2 ranging from 50% / 50% to 90% / 10%.

[0025] The volume distribution of the two catalysts, especially the second reaction section containing the second catalyst occupying a smaller volume than the first reaction section containing the first catalyst, can optimize the HDS, HDN and HDA reactions carried out in the first or second reaction section to obtain hydrocarbon fractions that meet the specifications, while improving the activity and stability of the catalytic system compared to a system containing only one catalyst.

[0026] According to an alternative form, the volume distribution V1 / V2 of the first and second hydrotreatment reaction stages is between 70% by volume / 30% by volume and 80% by volume / 20% by volume.

[0027] According to an alternative form, the second catalyst is characterized by:

[0028] - a nickel content expressed as NiO of 1.2% to 4.5% by weight relative to the total weight of the catalyst,

[0029] - a tungsten content expressed as WO3 of 16% to 33% by weight relative to the total weight of the catalyst,

[0030] - the phosphorus content, expressed as P2O5, is between 1% and 4% by weight, relative to the total weight of the catalyst.

[0031] According to an alternative form, the second catalyst is characterized by:

[0032] - a nickel content expressed as NiO of 1.3% to 4.3% by weight relative to the total weight of the catalyst,

[0033] - a tungsten content expressed as WO3 of 17 to 31% by weight relative to the total weight of the catalyst,

[0034] - the phosphorus content, expressed as P2O5, is between 1.3% and 3.4% by weight, relative to the total weight of the catalyst.

[0035] According to this alternative form, the second catalyst also has the following characteristics:

[0036] -Ni / W molar ratio is 0.18 to 0.45 mol / mol,

[0037] - The P / W molar ratio is 0.18 to 0.45 mol / mol.

[0038] According to an alternative form, 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.

[0039] According to an alternative form, the first catalyst has a molybdenum content (expressed as MoO3) ranging from 5% to 40% by weight relative to the total weight of the catalyst, and a nickel content (expressed as NiO) ranging from 1% to 10% by weight relative to the total weight of the catalyst.

[0040] According to an alternative form, the first catalyst also comprises phosphorus (expressed as P2O5) in a content ranging from 0.1% to 20% by weight relative to the total weight of the catalyst.

[0041] According to an alternative form, the first catalyst also contains oxygen-containing and / or nitrogen-containing and / or sulphur-containing organic compounds.

[0042] According to an alternative form, the organic compound is chosen from compounds containing one or more chemical functional groups selected from carboxyl, alcohol, thiol, thioether, sulfone, sulfoxide, ether, aldehyde, ketone, ester, carbonate, amine, nitrile, imide, oxime, urea or amide functional groups, or compounds containing a furan ring or a sugar, and 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, oxalic acid, gluconic acid, glucose, fructose, sucrose, sorbitol, xylitol, γ-ketovaleric acid, di(C1-C4 alkyl) succinate, and more specifically dimethyl succinate, dimethylformamide, 1-methyl-2-pyrrolidone, propylene carbonate, 2-methoxyethyl 3-oxobutyrate, N-bis(hydroxyethyl)glycine (bicine), tris(hydroxymethyl)methylglycine (tri cine), 2-furfural (also known as furfural), 5-hydroxymethylfurfural, 2-acetylfuran, 5-methyl-2-furfural, ascorbic acid, butyl lactate, ethyl lactate, butyl butyrolactate, ethyl 3-hydroxybutyrate, ethyl 3-ethoxypropionate, 2-ethoxyethyl acetate, 2-butoxyethyl acetate, 2-hydroxyethyl acrylate, 1-vinyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, 1, 5-pentanediol, 1-(2-hydroxyethyl)-2-pyrrolidone, 1-(2-hydroxyethyl)-2,5-pyrrolidinedione, 5-methyl-2(3H)-furanone, 1-methyl-2-piperidone, 4-aminobutyric acid, butyl glycolate, ethyl 2-mercaptopropionate, ethyl 4-oxopentanoate, diethyl maleate, dimethyl maleate, dimethyl fumarate, diethyl fumarate, dimethyl adipate and dimethyl 3-oxoglutarate.

[0043] According to an alternative form, the content of organic compound is between 1% and 30% by weight relative to the total weight of the catalyst.

[0044] According to an alternative form, the first catalyst and / or the second catalyst are at least partially sulphurized.

[0045] According to an alternative form, the hydrotreatment process is carried out as pretreatment in a fluid catalytic cracking process.

[0046] According to an alternative form, the hydrotreatment process is carried out as pretreatment in a hydrocracking process. DETAILED DESCRIPTION OF THE INVENTION

[0048] definition

[0049] According to the invention, the expressions "between ... and ..." and "... to ..." are equivalent and mean that the limits of the interval are included in the stated value range. If this is not the case and the limits are not included in the stated range, the invention discloses this fact.

[0050] Within the meaning of the present invention, various parameter ranges for a given stage, such as pressure ranges and temperature ranges, can be used alone or in combination. For example, within the meaning of the present invention, a range of preferred pressure values ​​can be combined with a range of more preferred temperature values.

[0051] Subsequently, specific and / or preferred embodiments of the present invention may be described. These embodiments may be used alone or in combination with each other, and the combination is not limited as long as it is technically feasible.

[0052] According to the present invention, unless otherwise stated, pressure is absolute pressure, also indicated as abs, and is given in units of MPa absolute (or MPa abs).

[0053] Subsequently, the families of chemical elements are given according to the CAS classification (CRC Handbook of Chemistry and Physics, published by CRC Press, edited by DRLide, 81st edition, 2000-2001). For example, family VIII according to the CAS classification corresponds to the metals of columns 8, 9 and 10 according to the new IUPAC classification.

[0054] The term "specific surface area" is understood to mean the BET specific surface area (S) determined by nitrogen adsorption according to standard ASTM D 3663-78 established by the Brunauer-Emmett-Teller method described in the journal "The Journal of the American Chemical Society", 1938, 60, 309. BET , unit is m 2 / g).

[0055] The total pore volume of the catalyst or of the support used to prepare the catalyst is understood to be the volume measured by mercury intrusion porosimetry according to standard ASTM D4284-83, at a maximum pressure of 4000 bar (400 MPa), using a surface tension of 484 dynes / cm and a contact angle of 140°. According to the recommendation of the publication “Techniques de l'ingénieur, traité analyse et caractérisation” [Techniques of the Engineer, Analysis and Characterization Treatise], pages 1050-1055, the wetting angle is taken to be 140°. In order to obtain greater precision, the value of the total pore volume corresponds to the value of the total pore volume measured on a sample by mercury intrusion porosimetry minus the value of the total pore volume measured on the same sample by mercury intrusion porosimetry at a pressure corresponding to 30 psi (about 0.2 MPa).

[0056] The content of Group VIII and Group VIb metals was measured using X-ray fluorescence.

[0057] The contents of Group VIb metals, Group VIII metals and phosphorus are expressed as oxides corrected for the loss on ignition of a catalyst sample kept in a muffle furnace at 550°C for 2 hours. The loss on ignition is due to the loss of volatile compounds. It is determined according to ASTM D7348.

[0058] Hydroprocessing refers to reactions including, inter alia, hydrodesulfurization (HDS), hydrodenitrogenation (HDN) and hydrogenation of aromatics (HDA).

[0059] raw material

[0060] The feedstock used in the hydrocracking method according to the present invention is a hydrocarbon feedstock, wherein at least 50% by weight of the compounds have an initial boiling point greater than 300° C. and a final boiling point less than 650° C., preferably at least 60% by weight, preferably at least 75% by weight, more preferably at least 80% by weight of the compounds have an initial boiling point greater than 300° C. and a final boiling point less than 650° C. The boiling point T5 of the feedstock is preferably greater than 300° C., preferably greater than 340° C., that is, 95% of the compounds present in the feedstock have a boiling point greater than 300° C., preferably greater than 340° C.

[0061] The hydrocracking process according to the present invention can process a wide variety of raw materials. The hydrocarbon raw material is advantageously selected from HCO (heavy cycle oil (heavy gas oil produced by a catalytic cracking unit)), vacuum distillate oils, such as gas oils produced by direct distillation of crude oil or by a conversion unit (such as catalytic cracking, coking or visbreaking), raw materials derived from aromatic extraction units, lubricating oil base oils or from solvent dewaxing of lubricating oil base oils, distillates derived from fixed bed or ebullient bed desulfurization or hydroconversion processes of atmospheric residue and / or vacuum residue and / or deasphalted oil, or the raw material can be deasphalted oil or conversion of raw materials containing vegetable oil or derived from biomass. It can also be paraffins produced by a Fischer-Tropsch process. The hydrocarbon raw material processed according to the hydrocracking process of the present invention can also be a mixture of the above raw materials, preferably, the raw material is a vacuum distillate oil.

[0062] The feedstocks processed, in particular the above-mentioned ones, generally contain heteroatoms such as sulphur, oxygen and nitrogen and, in the case of heavy feedstocks, they generally also contain metals.

[0063] The nitrogen content of the feedstock treated according to the process of the invention is generally greater than 500 ppm by weight, preferably from 500 to 10000 ppm by weight, more preferably from 700 to 4000 ppm by weight, and even more preferably from 1000 to 4000 ppm by weight.

[0064] The sulfur content of the feedstock treated according to the process of the present invention is generally from 0.01 to 5% by weight, preferably from 0.2 to 4% by weight, more preferably from 0.5 to 3% by weight.

[0065] The hydrocarbon feedstock may optionally contain metals, in particular nickel and vanadium. The total nickel and vanadium content of the hydrocarbon feedstock is preferably less than 50 ppm by weight, preferably less than 25 ppm, more preferably less than 10 ppm.

[0066] The hydrocarbon feedstock may optionally contain asphaltenes. The asphaltenes content of the hydrocarbon feedstock is generally less than 3000 ppm, preferably less than 1000 ppm, and more preferably less than 200 ppm.

[0067] The hydrocarbon feedstock may optionally contain resin. The resin content may be greater than 1% by weight, in particular greater than 5% by weight. The resin content is measured according to standard ASTM D2007-11. The hydrocarbon feedstock may also contain very small amounts of resin (less than 1% by weight).

[0068] The hydrocarbon feedstock may be of any chemical nature, that is to say, in addition to the aromatic content described below, may have any distribution of different chemical families selected from paraffins, olefins and cycloparaffins.

[0069] The aromatic content in the feedstock is greater than or equal to 20% by weight, preferably 25% to 90% by weight, more preferably 30% to 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 (published in 1955).

[0070] Implementation of the method and operating conditions

[0071] The process according to the invention can be carried out in one, two or more reactors. It is usually carried out in a fixed bed.

[0072] When the process according to the invention is carried out in two reactors, stage a) can be carried out in a first reactor comprising a first reaction stage through which the feedstock passes, and then stage b) can be carried out in a second reactor located downstream of the first reactor comprising a second reaction stage. Optionally, the effluent of stage a) emanating from the first reactor can be subjected to a separation stage, making it possible to separate the light fractions (comprising in particular the H2S and NH3 formed during the hydrotreatment in stage a)) from the heavy fraction comprising the partially hydrotreated hydrocarbons. The heavy fraction obtained after the separation stage is subsequently introduced into the second reactor, making it possible to carry out stage b) of the process according to the invention. The separation stage can be carried out by distillation, flash separation or any other method known to those skilled in the art.

[0073] When the process is carried out in a single reactor, stage a) is carried out in a first zone comprising a first reaction stage, and stage b) is carried out in a second zone comprising a second reaction stage, located downstream of the first zone.

[0074] The first hydroprocessing reaction section containing the first catalyst occupies a volume V1, and the second hydroprocessing reaction section containing the second catalyst occupies a volume V2, and the volume distribution V1 / V2 of the first and second hydroprocessing reaction sections is generally 50 vol% / 50 vol% to 90 vol% / 10 vol%, preferably 60 vol% / 40 vol% to 85 vol% / 15 vol%, and particularly preferably 70 vol% / 30 vol% to 80 vol% / 20 vol%.

[0075] The volume distribution of the two catalysts, especially 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 performed in the first or second reaction section. This is because the volume of the second catalyst is too large to quantitatively decompose the nitrogen-based compound, resulting in the inhibition of the HDA reaction. On the contrary, the volume of the second catalyst is too small to maximize the HDA reaction.

[0076] The operating conditions used in stage a) or b) of the hydrotreatment process according to the invention are generally as follows: the temperature is advantageously between 180° C. and 450° C., preferably between 250° C. and 440° C., the pressure is advantageously between 0.5 and 30 MPa, preferably between 1 and 18 MPa, and the hourly space velocity is advantageously between 0.1 and 20 h -1 , preferably 0.2 to 5h -1 The hourly space velocity (HSV) is defined here as the ratio of the hourly volume flow of the hydrocarbon feed to the volume of the catalyst or catalysts. The hydrogen / feed ratio, expressed as the volume of hydrogen / liquid feed measured under standard temperature and pressure conditions, is advantageously between 50 l / l and 5000 l / l, preferably between 80 and 2000 l / l.

[0077] The operating conditions in stages a) and b) may be the same or different. Preferably they are the same.

[0078] Composition of the catalyst used in the present invention

[0079] According to the present invention, the hydroprocessing method adopts the following sequence: a first catalyst comprising an alumina support and an active phase composed 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 composed of nickel and tungsten, phosphorus and an organic compound.

[0080] First Catalyst

[0081] The first catalyst comprises an alumina support and an active phase consisting of nickel and molybdenum. It may also contain phosphorus, an organic compound and optionally boron and / or fluorine.

[0082] The hydrogenation function of the first catalyst, also known as the active phase, is provided by nickel and molybdenum.

[0083] Preferably, the total content of nickel and molybdenum is advantageously greater than 6% by weight (expressed as oxides) relative to the total weight of the catalyst.

[0084] Preferably, the molybdenum content, expressed as MoO3, is between 5% and 40% by weight, preferably between 8% and 39% by weight, more preferably between 10% and 38% by weight, relative to the total weight of the catalyst.

[0085] Preferably, the nickel content, expressed as NiO, is from 1 to 10% by weight, preferably from 1.5 to 9% by weight, more preferably from 2 to 8% by weight, relative to the total weight of the catalyst.

[0086] Preferably, the molar ratio of nickel to molybdenum in the first catalyst is preferably from 0.1 to 0.8, preferably from 0.15 to 0.6, more preferably from 0.2 to 0.5.

[0087] The first catalyst may also contain phosphorus as a dopant. A dopant is an added element which does not exhibit any catalytic properties itself but increases the catalytic activity of the active phase.

[0088] The phosphorus content of the catalyst (expressed as P2O5) is from 0.1% to 20% by weight, preferably from 0.2% to 15% by weight, very preferably from 0.3% to 11% by weight, expressed as P2O5, relative to the total weight of the catalyst.

[0089] The molar ratio of phosphorus to molybdenum in the first catalyst is greater than or equal to 0.05, preferably greater than or equal to 0.07, preferably from 0.08 to 1, preferably from 0.1 to 0.9, very preferably from 0.15 to 0.8.

[0090] The first catalyst may also advantageously contain at least one dopant selected from boron, fluorine and mixtures of boron and fluorine.

[0091] When the catalyst contains boron or fluorine or a mixture of boron and fluorine, the content of boron or fluorine or the mixture of the two, expressed as elemental boron oxide and / or fluorine, is preferably from 0.1 to 10% by weight, preferably from 0.2 to 7% by weight, very preferably from 0.2 to 5% by weight, relative to the total weight of the catalyst.

[0092] The pore volume of the catalyst is usually 0.1 cm 3 / g to 1.5cm 3 / g, preferably 0.15cm 3 / g to 1.1cm 3 / g. The total pore volume is determined by mercury intrusion according to standard ASTM D4284, with a wetting angle of 140°, as described in the book Adsorption by Powders & Porous Solids: Principle, Methodology and Applications, Academic Press, 1999 by Rouquerol F., Rouquerol J. and Singh K., for example by Micromeritics TM Brand AutoporeIII TM Model Machine Measurement.

[0093] The first catalyst is characterized by a specific surface area of ​​5 to 400 m 2 / g, preferably 10 to 350m 2 / g, preferably 40 to 350m 2 / g, very preferably 50 to 300m 2 In the present invention, the specific surface area is measured by the BET method according to standard ASTM D3663, which is described in the same work mentioned above.

[0094] The support comprises alumina, preferably extruded alumina.The support preferably consists of alumina, preferably gamma alumina.

[0095] The alumina support advantageously has a diameter of 0.1 to 1.5 cm 3 .g -1 , preferably 0.4 to 1.1 cm 3 .g -1The total pore volume is determined by mercury intrusion according to standard ASTM D4284, with a wetting angle of 140°, as described in the book Adsorption by Powders & Porous Solids: Principle, Methodology and Applications, Academic Press, 1999 by Rouquerol F., Rouquerol J. and Singh K., for example by Micromeritics TM Brand AutoporeIII TM Model Machine Measurement.

[0096] The specific surface area of ​​the alumina support is advantageously between 5 and 400 m 2 .g -1 , preferably 10 to 350 m 2 .g -1 , more preferably 40 to 350 m 2 .g -1 In the present invention, the specific surface area is determined by the BET method according to standard ASTM D3663, which is described in the same work mentioned above.

[0097] The support is advantageously provided in the form of beads, extrudates, granules or irregular and non-spherical agglomerates, the specific shape of which may be produced by a crushing stage.

[0098] The first catalyst may also include an organic compound or a group of organic compounds known to have an additive effect. The effect of the additive is to improve the catalytic activity compared to a catalyst without the addition of an additive. More specifically, the catalyst may also include 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 also include one or more oxygen-containing organic compounds and / or one or more nitrogen-containing organic compounds. Preferably, the organic compound contains at least two carbon atoms and at least one oxygen and / or nitrogen atom, and does not contain other heteroatoms.

[0099] Typically, the organic compound is chosen from compounds comprising one or more chemical functional groups selected from carboxyl, alcohol, thiol, thioether, sulfone, sulfoxide, ether, aldehyde, ketone, ester, carbonate, amine, nitrile, imide, oxime, urea or amide functional groups, or compounds comprising a furan ring or a sugar.

[0100] The oxygen-containing organic compound can be one or more compounds selected from the group consisting of compounds containing one or more chemical functional groups selected from carboxyl, alcohol, ether, aldehyde, ketone, ester or carbonate functional groups, or compounds containing furan rings or sugar compounds. The oxygen-containing organic compound is understood here to be a compound that does not contain other heteroatoms. For example, the oxygen-containing organic compound can be one or more compounds selected from the group consisting of ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol (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, gluconic acid, tartaric acid, citric acid, γ-ketone Valeric acid, di(C1-C4 alkyl) succinate, more specifically dimethyl succinate, methyl acetoacetate, ethyl acetoacetate, 2-methoxyethyl 3-oxobutyrate, 2-methacryloyloxyethyl 3-oxobutyrate, dibenzofuran, crown ethers, phthalic acid, glucose, fructose, sucrose, sorbitol, xylitol, γ-valerolactone, 2-acetylbutyrolactone, propylene carbonate, 2-furfural (also known as furfural), 5-hydroxymethylfurfural (also known as 5-(hydroxymethyl)-2-furfural or 5-HMF), 2-acetylfuran, 5-methyl-2-furfural, methyl 2-furoate, furanmethanol (also known as furfuryl alcohol), furfuryl acetate, ascorbic acid, butyl lactate, ethyl lactate, butyl butyrolactate, ethyl 3-hydroxybutyrate, ethyl 3-ethoxypropionate, methyl 3-methoxypropionate, 2-ethoxyethyl acetate, 2-butoxyethyl acetate, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,5-hexanediol alcohol, 3-ethyl-1,5-pentanediol, 2,4-diethyl-1,5-pentanediol, 5-methyl-2(3H)-furanone, butyl glycolate, ethyl 4-oxopentanoate, 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.

[0101] The nitrogen-containing organic compound can be one or more compounds selected from the group consisting of one or more chemical functional groups selected from amine or nitrile functional groups. The nitrogen-containing organic compound is understood to be a compound that does not contain other heteroatoms. For example, the nitrogen-containing organic compound can be one or more compounds selected from ethylenediamine, diethylenetriamine, hexamethylenediamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, acetonitrile, octylamine, guanidine and carbazole.

[0102] The oxygen- and nitrogen-containing organic compound may be one or more compounds selected from the group consisting of compounds containing one or more chemical functional groups selected from carboxylic acid, alcohol, ether, aldehyde, ketone, ester, carbonate, amine, nitrile, imide, amide, urea or oxime functional groups. The oxygen- and nitrogen-containing organic compound is understood here to be a compound that does not contain other heteroatoms. For example, the oxygen- and nitrogen-containing organic compound may be one or more compounds selected from the group consisting of 1,2-cyclohexanediaminetetraacetic acid, monoethanolamine (MEA), 1-methyl-2-pyrrolidone, 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, N- Di(hydroxyethyl)glycine, tri(hydroxymethyl)methylglycine, 2-methoxyethyl cyanoacetate, 1-ethyl-2-pyrrolidone, 1-vinyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, 1-(2-hydroxyethyl)-2-pyrrolidone, 1-(2-hydroxyethyl)-2,5-pyrrolidinedione, 1-methyl-2-piperidone, 1-acetyl-2-azepanone, 1-vinyl-2-azepanone and 4-aminobutyric acid.

[0103] The sulfur-containing organic compound can be one or more compounds selected from compounds containing one or more chemical functional groups selected from thiol, thioether, sulfone or sulfoxide functional groups. For example, the sulfur-containing organic compound can be one or more compounds selected from thioglycolic acid, 2,2′-thiodiethanol, 2-hydroxy-4-methylthiobutyric acid, sulfone derivatives of benzothiophene or sulfoxide derivatives of benzothiophene, ethyl 2-mercaptopropionate, methyl 3-(methylthio)propionate and ethyl 3-(methylthio)propionate.

[0104] Preferably, the organic compound contains oxygen; preferably, it 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, di(C1-C4 alkyl) succinate, and more specifically dimethyl succinate, dimethylformamide, 1-methyl-2-pyrrolidone, propylene carbonate, 2-methoxyethyl 3-oxobutyrate, N-bis(hydroxyethyl)glycine, tris(hydroxymethyl)methylglycine, 2-furancarboxaldehyde (also known as furfural), 5-hydroxymethylfurfural (also known as 5-(hydroxymethyl)-2-furfural or 5-HMF), 2-acetylfuran , 5-methyl-2-furfural, ascorbic acid, butyl lactate, ethyl lactate, butyl butyrolactate, ethyl 3-hydroxybutyrate, ethyl 3-ethoxypropionate, 2-ethoxyethyl acetate, 2-butoxyethyl acetate, 2-hydroxyethyl acrylate, 1-vinyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, 1,5-pentanediol, 1-(2-hydroxyethyl)-2-pyrrolidone, 1-(2-hydroxyethyl)-2,5-pyrrolidinedione, 5-methyl-2(3H)-furanone, 1-methyl-2-piperidone, 4-aminobutyric acid, butyl glycolate, ethyl 2-mercaptopropionate, ethyl 4-oxopentanoate, diethyl maleate, dimethyl maleate, dimethyl fumarate, diethyl fumarate, dimethyl adipate and dimethyl 3-oxoglutarate.

[0105] When present, the total content of one or more organic compounds containing oxygen and / or nitrogen and / or sulfur in the catalyst is generally from 1% to 30% by weight, preferably from 1.5% to 25% by weight, more preferably from 2% to 20% by weight, relative to the total weight of the catalyst.

[0106] In catalyst preparation processes requiring a drying stage, the drying stage or stages after the introduction of the organic compound or compounds are carried out at a temperature below 200° C., so as to retain preferably at least 30%, preferably at least 50% and very preferably at least 70% of the amount of 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.

[0107] Second catalyst

[0108] 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 also comprise boron and / or fluorine.

[0109] The hydrogenation function of the second catalyst, also known as the active phase, is composed of nickel and tungsten.

[0110] The second catalyst is characterized by:

[0111] - a nickel content expressed as NiO of 1.2% to 4.5% by weight relative to the total weight of the catalyst,

[0112] - a tungsten content expressed as WO3 of 16% to 33% by weight relative to the total weight of the catalyst,

[0113] - the phosphorus content, expressed as P2O5, is between 1% and 4% by weight, relative to the total weight of the catalyst.

[0114] Preferably, the second catalyst is characterized by:

[0115] - a nickel content expressed as NiO of 1.3% to 4.3% by weight, preferably 1.4% to 3.8% by weight, more preferably 1.5% to 3.4% by weight, relative to the total weight of the catalyst,

[0116] - a tungsten content expressed as WO3 of 17 to 31% by weight, preferably 18 to 30% by weight, preferably 19 to 29% by weight, more preferably 20 to 26% by weight, relative to the total weight of the catalyst,

[0117] The phosphorus content, expressed as P2O5, is preferably from 1.3% to 3.4% by weight, preferably from 1.4% to 3.1% by weight, very preferably from 1.5% to 2.8% by weight, relative to the total weight of the catalyst.

[0118] Preferably, the Ni / W molar ratio is 0.18 to 0.45 mol / mol, preferably 0.20 to 0.43 mol / mol, more preferably 0.22 to 0.42 mol / mol.

[0119] Preferably, the P / W molar ratio is from 0.18 to 0.45 mol / mol, preferably from 0.20 to 0.43 mol / mol, more preferably from 0.22 to 0.42 mol / mol.

[0120] The catalyst is based on an active phase consisting of nickel and tungsten deposited on a silica-alumina support in the presence of phosphorus and an organic compound, and the different metals and / or phosphorus are present in a specific ratio as described above. Through a synergistic effect, the catalyst exhibits excellent hydroprocessing activity and stability, especially in hydrodenitrogenation (HDN) and aromatics hydrogenation (HDA) as well as hydrodesulfurization (HDS).

[0121] Without wishing to be bound by any one theory, the silica-alumina support of the second catalyst may modify the structure of the most recalcitrant aromatics (via isomerization and / or cracking reactions) making these molecules more reactive. Thus, optimizing the content of each metal (particularly tungsten, which is beneficial for hydrogenation) and phosphorus using specific ratios, combined with the silica-alumina support, may increase the HDA required in advance to increase the HDN, thereby improving the overall quality of catalytic performance.

[0122] Therefore, in a sequence having the first catalyst upstream, the second catalyst having the above-mentioned specific ratio is particularly preferred.

[0123] The second catalyst may also advantageously contain at least one dopant selected from boron, fluorine and a mixture of boron and fluorine. When such a dopant is present, its content is as described for the first catalyst.

[0124] The pore volume of the second catalyst is usually 0.1 cm 3 / g to 1.5cm 3 / g, preferably 0.15cm 3 / g to 1.1cm 3 / g. The total pore volume is determined by mercury intrusion according to standard ASTM D4284, with a wetting angle of 140°, as described in the book Adsorption by Powders & Porous Solids: Principle, Methodology and Applications, Academic Press, 1999 by Rouquerol F., Rouquerol J. and Singh K., for example by Micromeritics TM Brand AutoporeIII TM Model Machine Measurement.

[0125] The second catalyst is characterized by a specific surface area of ​​5 to 400 m 2 / g, preferably 10 to 350m 2 / g, preferably 40 to 350m 2 / g, very preferably 50 to 300m 2 In the present invention, the specific surface area is measured by the BET method according to standard ASTM D3663, which is described in the same work mentioned above.

[0126] The support of the second catalyst preferably consists of silica-alumina.

[0127] The total pore volume of the silica-alumina support is advantageously between 0.1 and 1.5 cm 3 .g -1 , preferably 0.2 to 0.8 cm 3.g -1 , particularly preferably 0.3 to 0.6 cm 3 .g -1 The total pore volume is determined by mercury intrusion according to standard ASTM D4284 with a wetting angle of 140°, as described in the work Adsorption by Powders & Porous Solids: Principle, Methodology and Applications, Academic Press, 1999 by Rouquerol F., Rouquerol J. and Singh K., for example by Micromeritics TM Brand Autopore III TM Model Machine Measurement.

[0128] The specific surface area of ​​the silica-alumina support is advantageously between 5 and 400 m 2 .g -1 , preferably 100 to 350 m 2 .g -1 , more preferably 200 to 300 m 2 .g -1 In the present invention, the specific surface area is determined by the BET method according to standard ASTM D3663, which is described in the same work mentioned above.

[0129] The silicon dioxide content in the support is at most 50% by weight, generally less than or equal to 45% by weight, preferably less than or equal to 40% by weight, relative to the total weight of the support. Preferably, the silicon dioxide content in the support is from 10% to 50% by weight, preferably from 15% to 40% by weight, particularly preferably from 20% to 35% by weight, relative to the total weight of the support.

[0130] Silicon sources are well known to the person skilled in the art. For example, silicic acid, silicon dioxide in powder form or in colloidal form (silica sol), or tetraethyl orthosilicate Si(OEt)4 may be mentioned.

[0131] The silica-alumina carrier may also advantageously contain zeolites in addition. In this case, any zeolite source and any related preparation method known to those skilled in the art may be incorporated. Preferably, the zeolite is selected from FAU, BEA, ISV, IWR, IWW, MEI, UWY, and preferably, the zeolite is selected from FAU and BEA, such as zeolite Y and / or beta zeolite, and particularly preferably such as USY and / or beta zeolite. When zeolite is present, its content is 0.1% to 50% by weight relative to the total weight of the carrier, preferably 0.1% to 10% by weight.

[0132] The support is advantageously provided in the form of beads, extrudates, granules or irregular and non-spherical agglomerates, the specific shape of which may be produced by a crushing stage.

[0133] The second catalyst according to the invention further comprises an organic compound or a group of organic compounds, the nature and amounts of which are described in the first catalyst section. When both catalysts comprise one or more organic compounds, the organic compounds may be the same or different.

[0134] Preferably, the organic compound of the second catalyst contains oxygen; preferably, it 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, di(C1-C4 alkyl) succinate, and more specifically dimethyl succinate, dimethylformamide, 1-methyl-2-pyrrolidone, propylene carbonate, 2-methoxyethyl 3-oxobutyrate, N-bis(hydroxyethyl)glycine, tris(hydroxymethyl)methylglycine, 2-furancarboxaldehyde (also known as furfural), 5-hydroxymethylfurfural (also known as 5-(hydroxymethyl)-2-furfural or 5-HMF), 2-acetylfuran 1-(2-hydroxyethyl)-2-pyrrolidone, 1-(2-hydroxyethyl)-2,5-pyrrolidinedione, 5-methyl-2(3H)-furanone, 1-methyl-2-piperidone, 4-aminobutyric acid, butyl glycolate, ethyl 2-mercaptopropionate, ethyl 4-oxopentanoate, diethyl maleate, dimethyl maleate, dimethyl fumarate, diethyl fumarate, dimethyl adipate and dimethyl 3-oxoglutarate.

[0135] According to a preferred embodiment, the hydroprocessing process adopts the following sequence: a first hydroprocessing reaction stage comprising a first catalyst based on nickel and molybdenum on an alumina support in the presence of phosphorus and an organic compound; and a second hydroprocessing reaction stage comprising a second catalyst based on nickel and tungsten on a silica-alumina support in the presence of phosphorus and an organic compound, said second catalyst being characterized by:

[0136] - a nickel content expressed as NiO of 1.3% to 4.3% by weight, preferably 1.4% to 3.8% by weight, more preferably 1.5% to 3.4% by weight, relative to the total weight of the catalyst,

[0137] - a tungsten content expressed as WO3 of 17 to 31% by weight, preferably 18 to 30% by weight, preferably 19 to 29% by weight, more preferably 20 to 26% by weight, relative to the total weight of the catalyst,

[0138] - the phosphorus content, expressed as P2O5, is preferably from 1.3 to 3.4% by weight, preferably from 1.4 to 3.1% by weight, very preferably from 1.5 to 2.8% by weight, relative to the total weight of the catalyst,

[0139] - Ni / W molar ratio is 0.18 to 0.45 mol / mol, preferably 0.20 to 0.43 mol / mol, more preferably 0.22 to 0.42 mol / mol,

[0140] - The P / W molar ratio is 0.18 to 0.45 mol / mol, preferably 0.20 to 0.43 mol / mol, more preferably 0.22 to 0.42 mol / mol.

[0141] According to this preferred embodiment, the first hydroprocessing reaction section comprising the first catalyst occupies a volume V1, and the second hydroprocessing reaction section comprising the second catalyst occupies a volume V2, and the volume distribution V1 / V2 of the first and second hydroprocessing reaction sections is 50 vol% / 50 vol% to 90 vol% / 10 vol%, preferably 60 vol% / 40 vol% to 85 vol% / 15 vol%, and particularly preferably 70 vol% / 30 vol% to 80 vol% / 20 vol%.

[0142] According to this embodiment, the organic compound is preferably selected from the group consisting of 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, di(C1-C4 alkyl) succinates, and more specifically dimethyl succinate, dimethylformamide, 1-methyl-2-pyrrolidone, propylene carbonate, 2-methoxyethyl 3-oxobutyrate, N-bis(hydroxyethyl)glycine, tris(hydroxymethyl)methylglycine, 2-furancarboxaldehyde (also known as furfural), 5-hydroxymethylfurfural (also known as 5-(hydroxymethyl)-2-furfural or 5-HMF), 2-acetylfuran, 5-methyl The compounds described herein are butyl lactate, ethyl lactate, butyl butyrolactate, ethyl 3-hydroxybutyrate, ethyl 3-ethoxypropionate, 2-ethoxyethyl acetate, 2-butoxyethyl acetate, 2-hydroxyethyl acrylate, 1-vinyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, 1,5-pentanediol, 1-(2-hydroxyethyl)-2-pyrrolidone, 1-(2-hydroxyethyl)-2,5-pyrrolidinedione, 5-methyl-2(3H)-furanone, 1-methyl-2-piperidone, 4-aminobutyric acid, butyl glycolate, ethyl 2-mercaptopropionate, ethyl 4-oxopentanoate, diethyl maleate, dimethyl maleate, dimethyl fumarate, diethyl fumarate, dimethyl adipate and dimethyl 3-oxoglutarate.

[0143] Preparation method

[0144] The first and second catalysts may be prepared according to any method for preparing supported catalysts known to those skilled in the art.

[0145] The first and second catalysts can be prepared according to a preparation method comprising the following stages:

[0146] i) contacting a nickel precursor, a molybdenum precursor or a tungsten precursor, phosphorus (when present) and an organic compound (when present) with an alumina or silica-alumina based support to obtain a catalyst precursor,

[0147] ii) drying the catalyst precursor obtained from stage i) at a temperature below 200° C.,

[0148] iii) optionally, calcining the catalyst precursor obtained in stage ii) at a temperature of 200° C. to 550° C.,

[0149] iv) Optionally, sulphurizing the catalyst obtained in stage ii) or stage iii).

[0150] During the contacting operation of stage i), the first and second catalysts can be prepared by impregnating the metals and phosphorus onto the selected support. The impregnation can be carried out, for example, according to the dry impregnation method known to those skilled in the art, in which the desired elements in the form of soluble salts are introduced in appropriate amounts into the selected solvent (for example demineralized water) in order to fill the pores of the support as accurately as possible.

[0151] The precursors of the active phase can be introduced simultaneously or successively. The impregnation of each precursor can advantageously be carried out at least twice. Thus, different precursors can advantageously be impregnated successively with different impregnation and aging times. One precursor can also be impregnated multiple times.

[0152] Preferably, the precursors of the active phase are introduced simultaneously.

[0153] The nickel precursor that can be used is advantageously selected from the group consisting of nickel oxides, hydroxides, basic carbonates, carbonates and nitrates; for example, basic nickel carbonate, nickel carbonate or nickel hydroxide is preferably used.

[0154] The molybdenum precursors which can be used are well known to those skilled in the art. For example, among the molybdenum sources, oxides and hydroxides, molybdic acid and its salts, in particular ammonium salts, such as ammonium molybdate or ammonium heptamolybdate, phosphomolybdic acid (HPMo), 12 O 40 ) and its salts, and optionally silicomolybdic acid (H4SiMO 12 O 40 ) and their salts. The molybdenum source may also be, for example, a heteropoly compound of the Keggin, vacant Keggin, substituted Keggin, Dawson, Anderson or Strandberg type. Molybdenum trioxide and heteropoly anions of the Strandberg, Keggin, vacant Keggin or substituted Keggin type are preferably used.

[0155] The tungsten precursors that can be used are also well known to those skilled in the art. For example, among the tungsten sources, oxides and hydroxides, tungstic acid and its salts, in particular ammonium salts, such as ammonium tungstate or ammonium metatungstate, phosphotungstic acid and its salts, and optionally silicotungstic acid (H4SiW 12 O 40 ) and their salts. The tungsten source may also be, for example, a heteropoly compound of the Keggin, vacant Keggin, substituted Keggin or Dawson type. Preferably, oxides and ammonium salts, such as ammonium metatungstate, or heteropoly anions of the Keggin, vacant Keggin or substituted Keggin type are used.

[0156] The phosphorus can be introduced in whole or in part by impregnation. It is preferably introduced by impregnation, preferably dry impregnation, using a solution containing nickel, molybdenum or tungsten precursors.

[0157] The phosphorus can advantageously be introduced alone or as a mixture with the active phase, and this can be done during any stage of the impregnation of the hydrogenation functional (if the hydrogenation functional is introduced several times). The phosphorus can also be introduced in whole or in part during the impregnation of the oxygen- and / or nitrogen- and / or sulfur-containing organic compound (if the organic compound is introduced separately from the hydrogenation functional (post-impregnation and pre-impregnation cases, described later)). It can also be introduced by the synthesis of the support at any stage of the support synthesis. Thus, it can be introduced before, during or after the kneading of the selected alumina gel matrix (for example and preferably, aluminum oxyhydroxide (boehmite), which is an alumina precursor).

[0158] The preferred phosphorus precursor is orthophosphoric acid H3PO4, but its salts and esters, such as ammonium phosphate, are also suitable. Phosphorus can also be introduced simultaneously with one or more Group VIb elements in the form of Keggin, occlusive Keggin, substituted Keggin or Strandberg type heteropolyanions.

[0159] Any impregnation solution described in the present invention may contain any polar solvent known to those skilled in the art. The polar solvent used is advantageously selected from methanol, ethanol, water, phenol and cyclohexanol, used alone or as a mixture. Preferably, a polar protic solvent is used. A list of common polar solvents and their dielectric constants can be found in the book "Solvents andSolvent Effects in Organic Chemistry", C. Reichardt, Wiley-VCH, 3rd edition, 2003, pages 472-474. Very preferably, the solvent used is water or ethanol, particularly preferably, the solvent is water. In a possible embodiment, the solvent may not be present in the impregnation solution.

[0160] When the first or second catalyst additionally comprises a dopant selected from boron, fluorine or a mixture of boron and fluorine, the introduction of this(these) dopant(s) may be carried out in various ways at various stages of the preparation in the same manner as the above-mentioned introduction of phosphorus.

[0161] The boron precursor can be boric acid, orthoboric acid H3BO3, ammonium diborate or ammonium pentaborate, boron oxide or boric ester. Boron can be introduced by, for example, a solution of boric acid in a water / alcohol mixture or a water / ethanolamine mixture. If boron is introduced, the boron precursor is preferably orthoboric acid.

[0162] Fluorine precursors that can be used are well known to those skilled in the art. For example, fluoride anions can be introduced in the form of hydrofluoric acid or its salts. These salts are formed from alkali metals, ammonium or organic compounds. In the latter case, advantageously, the salt is formed in the reaction mixture by the reaction of the organic compound with hydrofluoric acid. For example, fluorine can be introduced by impregnation with an aqueous solution of hydrofluoric acid or ammonium fluoride or ammonium difluoride.

[0163] The oxygen- and / or nitrogen- and / or sulfur-containing organic compound of the second catalyst or, when present, the oxygen- and / or nitrogen- and / or sulfur-containing organic compound of the first catalyst is introduced before the drying stage ii). The organic compound is generally introduced by impregnation in the presence or absence of an active phase and phosphorus and in the presence or absence of a solvent.

[0164] The introduction of the organic compound comprises several embodiments which differ in particular in the moment of introduction of the organic compound relative to the introduction of the metal. It can be carried out simultaneously with the metal impregnation (co-impregnation), or after the metal impregnation (post-impregnation), or finally before the metal impregnation (pre-impregnation), in particular during the preparation of the support, and preferably during shaping or on a preformed support. Each embodiment, alone or in combination, can be carried out in one or more stages.

[0165] Furthermore, the contacting stage may combine at least two embodiments, such as co-impregnation and post-impregnation. According to an alternative embodiment, the contacting operation according to stage i) combines at least two contacting embodiments, such as co-impregnation of the active phase and phosphorus with an organic compound, followed by drying at a temperature below 200° C. and then post-impregnation with an organic compound, which may be the same or different from the organic compound used for the co-impregnation. Each embodiment, alone or in combination, may be carried out in one or more stages.

[0166] The organic compound of the second catalyst and the organic compound of the first catalyst (when present) are preferably introduced in a post-impregnation. In this case, the metal and phosphorus are introduced first, dried at a temperature below 200° C., the organic compound is introduced and then dried at a temperature below 200° C., without subsequent calcination.

[0167] Advantageously, one or more organic compounds are introduced into the impregnation solution, which may be the same solution or a different solution from the solution containing the precursors of the active phase and of the phosphorus, according to the manufacturing embodiment, in amounts corresponding to:

[0168] the molar ratio of the organic compound to the sum of the one or more elements of Group VIb of the catalyst precursor (Mo in the first catalyst or W in the second catalyst), calculated on the basis of the components introduced into the one or more impregnation solutions, is from 0.01 to 5 mol / mol, preferably from 0.05 to 3 mol / mol, preferably from 0.05 to 1.5 mol / mol, very preferably from 0.1 to 1.2 mol / mol, and

[0169] The molar ratio of organic compound to nickel, calculated on the basis of the components introduced into the impregnation solution or solutions, is from 0.02 to 17 mol / mol, preferably from 0.1 to 10 mol / mol, preferably from 0.15 to 8 mol / mol, very preferably from 0.6 to 5 mol / mol.

[0170] When several organic compounds are present, a different molar ratio applies for each organic compound present.

[0171] Advantageously, after each impregnation stage, the impregnated support is ripened. Ripening enables the impregnation solution to be evenly dispersed within the support.

[0172] Any aging stage described in the present invention is advantageously carried out at atmospheric pressure, in a water-saturated atmosphere and at a temperature of 17° C. to 50° C., and preferably at ambient temperature. Typically, an aging time of 10 minutes to 48 hours, preferably 30 minutes to 5 hours, is sufficient. Longer times are not excluded, but do not necessarily bring any improvement.

[0173] According to stage ii) of the preparation process according to the invention, the optionally aged catalyst precursor obtained in stage i) is subjected to a drying stage at a temperature below 200° C., preferably at 50° C. to 180° C., preferably at 70° C. to 150° C., very preferably at 75° C. to 130° C.

[0174] The drying stage is advantageously carried out by any technique known to the person 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 traversed bed using hot air or any other hot gas. Preferably, when the drying is carried out in a fixed bed, the gas used is air or an inert gas, such as argon or nitrogen. Very preferably, the drying is carried out in the presence of nitrogen and / or air in a traversed bed. Preferably, the drying stage has a short duration of 5 minutes to 4 hours, preferably 30 minutes to 4 hours, very preferably 1 hour to 3 hours. When an organic compound is present, drying is then carried out to preferably retain at least 30% of the organic compound introduced; preferably, this amount is greater than 50%, more preferably greater than 70%, calculated on the basis of the carbon remaining on the catalyst. At the end of the drying stage b), a dried catalyst is obtained.

[0175] Optionally, the drying stage ii) may be followed by a calcination stage iii).

[0176] According to this alternative form, at the end of the drying stage ii), a calcination stage c) is carried out at a temperature ranging from 200° C. to 600° C., preferably from 250° C. to 550° C., under an inert atmosphere (for example nitrogen) or an oxygen-containing atmosphere (for example air). 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 present in the form of an oxide; the heteropolyanions are thus converted into oxides. Likewise, when an organic compound is introduced, the catalyst no longer contains or contains very little organic compound. However, the introduction of an organic compound during its preparation can increase the dispersibility of the active phase, thus producing a more active catalyst.

[0177] When organic compounds are present, the catalyst is preferably not calcined. The term "calcined" is understood here to mean a heat treatment at a temperature greater than or equal to 200° C. under a gas containing air or oxygen.

[0178] However, the catalyst precursor may undergo a calcination stage before the introduction of the organic compound, in particular after the impregnation of the active phase and of the phosphorus.

[0179] The first or second catalyst may be a fresh catalyst, that is to say a catalyst which has not been used previously as a catalyst in a catalytic unit, in particular in a hydroprocessing.

[0180] The first or second catalyst according to the invention may also be a regenerated and / or restored catalyst. A regenerated and / or restored catalyst is understood to mean a catalyst which has been used as a catalyst in a catalytic unit, in particular in a hydrotreatment and / or hydrocracking, and has undergone at least one stage of partial or complete removal of coke, for example by calcination (regeneration). Regeneration may be carried out by any method known to those skilled in the art. Regeneration is generally carried out by calcining at a temperature of 350°C to 550°C, and generally at 400°C to 520°C, or at 420°C to 520°C, or at a temperature of 450°C to 520°C, temperatures below 500°C being generally advantageous.

[0181] When the regenerated catalyst no longer contains enough active phase or phosphorus, or when it exhibits one or more ratios outside the above-mentioned preferred ratios, the regenerated catalyst can be restored 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 metal and phosphorus or separately. When the catalyst contains such an organic compound, the organic compound introduced may be the same or different from the organic compound of the fresh catalyst. Of course, the above-mentioned operating conditions for slaking, drying and optionally calcining and optionally sulfiding apply to this last embodiment.

[0182] Before being used in the hydroprocessing reaction, the first catalyst and / or the second catalyst are advantageously converted into a sulfided catalyst to form its active entity. This activation or sulfidation stage is carried out by methods well known to those skilled in the art and is advantageously carried out in the presence of hydrogen and hydrogen sulfide under a sulfur reducing atmosphere.

[0183] According to an alternative form, the first or second catalyst advantageously undergoes a sulphurization stage after the drying stage ii) or the optional calcination stage iii).

[0184] The catalyst is advantageously non-original or original position sulfurized. The sulfurizing agent is H2S gas, elemental sulfur, CS2, mercaptan, sulfide and / or polysulfide, hydrocarbon fractions of sulfur-containing compounds with a boiling point lower than 400 ℃ or any other sulfur-containing compounds for activating hydrocarbon feedstock with sulfurized catalyst. The sulfur-containing compound is advantageously selected from alkyl disulfides, such as dimethyl disulfide (DMDS), alkyl sulfides, such as dimethyl sulfide, mercaptan, such as polysulfide compounds of n-butyl mercaptan (or 1-butyl mercaptan) and tertiary nonyl polysulfide types. The catalyst can also be sulfurized by sulfur contained in the desulfurized feedstock. 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 to which dimethyl disulfide has been added.

[0185] Application of the method of the present invention in a hydrocracking method

[0186] According to a first alternative form, the hydrotreatment process of the invention is advantageously carried out as a pretreatment in a hydrocracking process, more particularly a "single-stage" hydrocracking process or a "two-stage" hydrocracking process. The hydrocracking process can convert petroleum fractions, in particular vacuum distillates (VD), into lighter and more easily upgraded products (gasoline, middle distillates). The hydrotreatment process of the invention aims to remove the sulphur-based, nitrogen-based or aromatic compounds present in the vacuum distillates.

[0187] The "single-stage" hydrocracking process generally first comprises a thorough hydrotreatment, the purpose of which is to perform a thorough HDN, a thorough HDS and a thorough HDA on the feedstock before it is sent to one or more hydrocracking catalysts. The single-stage hydrocracking process is particularly advantageous when the one or more hydrocracking catalysts comprise a support containing zeolite crystals. This thorough hydrotreatment of the feedstock only results in a limited conversion of the feedstock into lighter fractions, which is still insufficient and must therefore be completed on one or more hydrocracking catalysts with higher activity. However, it should be noted that no separation of the effluents occurs between the different catalytic beds: all effluents at the outlet of the hydrotreatment catalytic bed are injected into one or more catalytic beds containing the one or more hydrocracking catalysts, and the products formed are then separated. This hydrocracking has an alternative form, namely, the unconverted portion is recycled to at least one hydrocracking catalytic bed in order to more thoroughly convert the feedstock. Advantageously, the hydrotreatment process according to the invention comprises being carried out upstream of the hydrocracking catalyst in the single-stage hydrocracking process according to a specific sequence according to the invention. Furthermore, it makes it possible to limit the nitrogen content at the end of the pretreatment stage in order to protect the zeolite-based hydrocracking catalysts which are very sensitive to nitrogen.

[0188] The "two-stage" hydrocracking process comprises a first stage, the purpose of which is the same as that of the "single-stage" process, to hydrotreat the feedstock while achieving a conversion of the feedstock of generally about 40% to 60%. The effluent produced in the first stage is subsequently separated, generally by distillation, generally called intermediate separation, the purpose of which is to separate the conversion products from the unconverted part. In the second stage of the two-stage hydrocracking process according to the invention, only the part of the feedstock that was not converted during the first stage is treated. This separation makes the two-stage hydrocracking process according to the invention more selective for middle distillates (kerosene + diesel) than the single-stage process according to the invention. This is because the intermediate separation of the conversion products prevents them from being "over-cracked" by one or more hydrocracking catalysts in the second stage to produce naphtha and gas. In addition, it should be noted that the unconverted part of the feedstock treated in the second stage generally contains very low contents of NH3 and organic nitrogen-based compounds, generally less than 20 weight ppm, in fact even less than 10 weight ppm.

[0189] The first stage is carried out in the presence of a catalyst of a specific sequence according to the invention and a hydrocracking catalyst for hydrotreatment and the conversion is generally between about 40% and 60%. The catalytic bed of the catalyst of a specific sequence according to the invention is advantageously located upstream of the hydrocracking catalyst. The second stage is generally carried out in the presence of a hydrocracking catalyst of a different composition than that used to implement the first stage.

[0190] The hydrocracking process is generally carried out at a temperature of 250°C to 480°C, advantageously 320°C to 450°C, preferably 330°C to 435°C, at a pressure of 2 to 25 MPa, preferably 3 to 20 MPa, the hourly space velocity (HSV) of the feed relative to the volume of each catalyst advantageously being 0.1 to 40 h -1 , preferably 0.2 to 12h -1 , very preferably 0.4 to 6h -1 , and the hydrogen / feedstock ratio (in standard cubic meters (Sm 3 ) Hydrogen / cubic meter (m 3 ) hydrocarbon feedstock represents) advantageously 80Sl / l to 5000Sl / l, preferably 100 to 2000Sl / l. The pressure and conversion range covered by the hydrocracking process of vacuum distillate extends from mild hydrocracking to high pressure hydrocracking. Mild hydrocracking refers to hydrocracking that produces a moderate conversion (usually less than 40%), and the operating pressure is low (preferably 2MPa to 6MPa).

[0191] Hydrocracking catalysts are of the bifunctional type: they combine an acid function with a hydrogenation / dehydrogenation function. The acid function is provided by a porous support, the surface area of ​​which is typically 150 to 800 m 2 .g -1 , and have surface acidity, such as halogenated (especially chlorinated or fluorinated) alumina, combinations of boron and alumina, amorphous or crystalline mesoporous aluminosilicates and zeolites dispersed in oxide binders. The hydrogenation / dehydrogenation function is provided by an active phase based on at least one metal of Group VIb and optionally at least one metal of Group VIII in the periodic table. The most common formulations are nickel-molybdenum (NiMo) and nickel-tungsten (NiW) types, while cobalt-molybdenum (CoMo) types are less common. After preparation, the hydrogenation / dehydrogenation function is usually present in the form of an oxide. A common method for forming the hydrogenation / dehydrogenation phase of a hydrocracking catalyst comprises depositing one or more molecular precursors of at least one Group VIb metal and optionally at least one Group VIII metal on an acidic oxide support by a "dry impregnation" technique, followed by a ripening, drying and calcination stage to form an oxidized form of one or more of the metals used. Since the active and stable form of the hydrocracking process is the sulfided form, these catalysts must undergo a sulfiding stage. The sulphurization stage can be carried out in the plant of the process in question (known as in-situ sulphurization) or before the catalyst is loaded into the plant (known as ex-situ sulphurization).

[0192] Application of the method of the present invention in FCC method

[0193] According to a second alternative form, the hydroprocessing process of the present invention is advantageously carried out as a pretreatment in a fluidized catalytic cracking (or fluidized catalytic cracking, FCC) process. The FCC process can be carried out in a conventional manner known to those skilled in the art under suitable cracking conditions to produce lower molecular weight hydrocarbon products. For example, a brief description of catalytic cracking (its first industrial application can be traced back to 1936 (Houdry process) or 1942, using fluidized bed catalysts) can be found in Ullmann's Encyclopedia of Industrial Chemistry, Volume A18, 1991, pages 61 to 64.

[0194] Conventional catalysts comprising a matrix, optional additives and at least one zeolite are generally used in the FCC method. The amount of zeolite is variable, but is generally 3% to 60% by weight relative to the weight of the catalyst, often 6% to 50% by weight, and generally 10% to 45% by weight. Zeolite is generally dispersed in the matrix. The amount of the additive is generally 0% to 30% by weight relative to the weight of the catalyst, and often 0% to 20% by weight. The amount of the matrix is ​​to supplement to 100% by weight. The additive is generally selected from the oxide of the metal of Group IIa of the Periodic Table of Elements, such as magnesium oxide or calcium oxide, rare earth metal oxides and the titanate of Group IIa metals. The matrix is ​​generally two or more mixtures of silicon dioxide, aluminum oxide, silicon dioxide-aluminum oxide, silicon dioxide-magnesium oxide, clay or these products. The most commonly used zeolite is Y zeolite.

[0195] The cracking is carried out in a substantially vertical reactor, either in the upward mode (riser) or in the downward mode (downcomer). The choice of catalyst and operating conditions depends on the desired product, which varies according to the feedstock treated, as described, for example, in the paper by M. Marcilly, pp. 990-991, published in the revue de l'institut du pétrole [Review of the French Institute of Petroleum], November-December 1975, pp. 969-1006. Operation is usually carried out at temperatures of 450°C to 600°C, with residence times in the reactor of less than 1 minute, usually 0.1 to 50 seconds.

[0196] Pretreatment also makes it possible to limit the nitrogen content at the end of the pretreatment stage in order to protect the zeolite-based catalytic cracking catalysts which are very sensitive to nitrogen. Example

[0197] The following examples demonstrate that the use of specific sequences of the present invention can significantly increase HDA and HDN activities.

[0198] Examples 1 to 3 describe the preparation of catalysts C1 to C3. The final composition of the metals and phosphorus (expressed in the form of oxides, relative to the weight of the catalyst) and the Ni / W and P / W ratios of each catalyst are listed in Table 1 below.

[0199] Examples 4 to 8 describe the evaluation of different catalysts and / or sequences of catalysts C1, C2 and C3 in the hydrodenitrogenation (HDN) and hydrogenation of aromatics (HDA) of vacuum distillates.

[0200] Example 1: Preparation of NiMoP Catalyst C1 on Alumina

[0201] Nickel, molybdenum and phosphorus were added to 100 g of an alumina support A1 having a loss on ignition of 4.1 wt % and a BET specific surface area of ​​263 m 2 / g, a pore volume of 0.66 ml / g as measured by mercury intrusion, an average pore size of 9.7 nm (defined as the volume median diameter as measured by mercury intrusion), and was provided in the form of "extrudates". The water absorption volume of support A1 was 0.72 ml / g. The impregnation solution was prepared by the following steps: 32.9 g of molybdenum oxide (Merck TM , purity> 99.5 wt%), 10.5 g basic nickel carbonate (Merck TM , purity 99.9 wt%) and 12.78 g of orthophosphoric acid solution (Merck TM , 85 wt. % in water) was dissolved in 53.7 ml of distilled water. After dry impregnation, the extrudates were aged for 24 hours at ambient temperature in a water-saturated atmosphere and then dried at 90° C. for 16 hours. Subsequently, the dry impregnated support of catalyst C1 was doped by dry impregnation with a solution containing a mixture of dimethyl succinate (DMSU) and acetic acid (purity 75%). The molar ratios were as follows: DMSU / Mo=0.85 mol / mol, DMSU / acetic acid=0.5 mol / mol. The catalyst was again subjected to a 3-hour maturation phase in air at 20° C. and then dried in a horizontal hearth furnace at 120° C. for 3 hours. The dry catalyst thus obtained is denoted C1. The final composition of catalyst C1 (expressed in oxide form) was as follows: MoO3=22+ / -0.2 (wt. %), NiO=4.5+ / -0.1 (wt. %) and P2O5=5.3+ / -0.1 (wt. %).

[0202] Example 2: Preparation of NiWP catalyst C2 on silica-alumina

[0203] Nickel, tungsten and phosphorus were added to 100 g of an amorphous silica-alumina support ASA1 having a loss on ignition of 1.5 wt. % and a BET surface area of ​​240 m 2 / g, a pore volume of 0.46 ml / g as measured by mercury intrusion, an average pore size of 7.42 nm (defined as the volume median diameter as measured by mercury intrusion), and was provided in the form of "extrudates". The water absorption volume of the support ASA1 was 0.56 ml / g. The impregnation solution was prepared by the following steps: 43.93 g of phosphotungstic acid hydrate (Merck TM , purity> 99.5 wt%), 2.97 g phosphoric acid (Merck TM , 85 wt. % in water), 7.26 g basic nickel carbonate (Merck TM , purity 99.9 wt %) was dissolved in 48.1 ml of distilled water. After dry impregnation, the extrudates were aged in a water-saturated atmosphere at ambient temperature for 24 hours and then dried at 120° C. for 5 hours.

[0204] Subsequently, the dry impregnated support of catalyst C2 was doped by dry impregnation with a solution containing an aqueous solution of γ-ketovaleric acid. The molar ratio was as follows: γ-ketovaleric acid / W = 0.8 mol / mol. The catalyst was again subjected to a 3-hour aging phase at 20°C in air and then dried in a horizontal hearth furnace at 120°C for 3 hours. The dried catalyst thus obtained is denoted C2.

[0205] The final composition of catalyst C2 (expressed in oxide form) is as follows: WO3=25+ / -0.2 (wt%), NiO=3.22+ / -0.1 (wt%) and P2O5=1.91+ / -0.1 (wt%).

[0206] Example 3: Preparation of NiWP catalyst C3 on alumina

[0207] Nickel, tungsten and phosphorus were added to the same carrier A1 as in Example 1. The impregnation solution was prepared by the following steps: 48.18 g of phosphotungstic acid hydrate (Merck TM , purity> 99.5 wt%), 3.32 g phosphoric acid (Merck TM , 85 wt. % in water), 8.12 g basic nickel carbonate (Merck TM , purity 99.9 wt %) was dissolved in 69.4 ml of distilled water. After dry impregnation of 100 g of carrier A1, the extrudate was aged in a water-saturated atmosphere at ambient temperature for 24 hours and then dried at 120° C. for 5 hours.

[0208] Subsequently, the dry impregnated support of catalyst C3 was doped by dry impregnation with a solution containing an aqueous solution of γ-ketovaleric acid. The molar ratio was as follows: γ-ketovaleric acid / W = 0.8 mol / mol. The catalyst was again subjected to a 3-hour aging phase at 20°C in air and then dried in a horizontal hearth furnace at 120°C for 3 hours. The dried catalyst thus obtained is denoted C3.

[0209] The final composition of catalyst C3 (expressed in oxide form) is as follows: WO3=27+ / -0.2 (wt%), NiO=3.48+ / -0.1 (wt%) and P2O5=2.07+ / -0.1 (wt%).

[0210]

[0211]

[0212] Table 1: Composition of catalysts C1, C2 and C3

[0213] Example 4-7: Evaluation of the catalyst or a sequence of catalysts C1, C2 and C3 in the hydrodenitrogenation (HDN) and aromatics hydrogenation (HDA) of vacuum distillates

[0214] Catalysts and / or catalyst sequences taken from catalysts C1, C2 and C3 were tested in the hydrodenitrogenation (HDN) and hydrogenation of aromatics (HDA) of vacuum distillates.

[0215] The raw materials are based on H-Oil TM Methods Vacuum distillate oil (light vacuum gas oil) is obtained by deep hydrogenation of vacuum residue oil. The properties of the test raw materials used are as follows: Density at 15°C = 0.92 g / cm 3 (NF EN ISO 12185), refractive index at 20° C. = 1.5122 (ASTM D1218-12), sulfur content = 0.59 wt. %, nitrogen content = 2720 wt. ppm.

[0216] Simulated distillation (ASTM D2887):

[0217] -IP: 240.7℃;

[0218] -10%: 331.5℃;

[0219] -50%: 424.9℃;

[0220] -90%: 539.4℃;

[0221] -FP: 600.9℃.

[0222] The tests were carried out in an isothermal pilot reactor with a transverse fixed bed, with the fluid circulating from the bottom upwards. The reactor consisted of two catalytic zones, allowing the evaluation of different sequences of catalysts C1, C2 and C3. The feedstock first passed through the first zone, which was filled with the first catalyst, and then through the second zone, which was filled with the second catalyst.

[0223] According to Example 4 (according to the invention), the first zone is filled with catalyst C1 (70% by volume) and the second zone is then filled with catalyst C2 (30% by volume).

[0224] According to example 5 (according to the invention), the first zone is filled with catalyst C1 (50% by volume) and the second zone is then filled with catalyst C2 (50% by volume).

[0225] According to Example 6 (not according to the invention), both zones were filled with catalyst C1 (100% by volume).

[0226] According to Example 7 (not according to the invention), both zones were filled with catalyst C2 (100% by volume).

[0227] According to Example 8 (not according to the invention), the first zone was filled with catalyst C1 (70% by volume) and the second zone was then filled with catalyst C3 (30% by volume).

[0228] The catalyst was previously prepared in a reactor at 350°C under pressure by atmospheric (straight run) distillation of a gas oil feedstock (density at 15°C = 0.8491 g / cm 3 (NF EN ISO 12185) and initial sulfur content = 0.42 wt%), and 2 wt% of dimethyl disulfide was added thereto for in-situ sulfurization.

[0229] The catalytic tests were carried out under the following operating conditions: total pressure of 14 MPa and total volume of the two catalytic zones of 9 cm 3 , temperature is 390℃ to 415℃, hydrogen flow rate is 15.8l / h, raw material flow rate is 14.4cm 3 / h.

[0230] The characteristics of the effluent were 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 content was calculated by the ndM method (ASTM D3238). The degree of aromatic hydrogenation was calculated as the ratio of the aromatic carbon content in the feed minus the aromatic carbon content in the effluent to the aromatic carbon content in the test feed. The degree of hydrodenitrogenation was calculated as the nitrogen content in the feed minus the ratio of the nitrogen content in the effluent to the nitrogen content in the test feed.

[0231] The catalytic performance qualities of the tested catalyst sequence are given in Table 2. They are expressed as relative volume activity (RVA) relative to 100 vol. % of catalyst C1 (Example 6) chosen as reference, assuming an order of 1.2 for the HDA reaction and an order of 1 for the HDN reaction.

[0232] Table 2 clearly shows that the specific sequence according to the present invention contributes to the increased catalytic effect. This is because the catalyst sequence according to the present invention can significantly increase the volumetric activity in the hydrodearomatization (HDA) and hydrodenitrogenation (HDN) reactions of vacuum distillate oil.

[0233]

[0234] Table 2: Relative HDA and HDN activities of specific sequences according to the invention (Examples 4 and 5) and not according to the invention (Examples 6 to 8).

Claims

1. A method for hydrotreating a hydrocarbon feedstock to obtain a hydrotreated effluent, wherein at least 50% by weight of the compounds in the hydrocarbon feedstock have an initial boiling point greater than 300°C and a final boiling point less than 650°C, the temperature of the method being 180°C to 450°C, the pressure being 0.5 to 30 MPa, and the hourly space velocity being 0.1 to 20 h -1 , a hydrogen / feedstock ratio expressed as volume of hydrogen / volume of liquid feedstock measured under standard temperature and pressure conditions of 50 l / l to 5000 l / l, the process comprising the following stages: a) a first hydrotreatment stage, 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 stage, 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 stage a), said second catalyst comprising a silica-alumina support, an active phase composed of nickel and tungsten, phosphorus and an organic compound containing oxygen and / or nitrogen and / or sulphur.

2. The hydroprocessing method according to claim 1, wherein the first hydroprocessing reaction section containing the first catalyst occupies a volume V1, and the second hydroprocessing reaction section containing the second catalyst occupies a volume V2, and the volume distribution V1 / V2 of the first and second hydroprocessing reaction sections is 50 volume% / 50 volume% to 90 volume% / 10 volume%.

3. The hydroprocessing method according to claim 2, wherein the volume distribution V1 / V2 of the first and second hydroprocessing reaction zones is 70 vol% / 30 vol% to 80 vol% / 20 vol%.

4. The hydroprocessing process according to any one of the preceding claims, wherein the second catalyst is characterized by: - a nickel content expressed as NiO of 1.2% to 4.5% by weight relative to the total weight of the catalyst, - a tungsten content expressed as WO3 of 16% to 33% by weight relative to the total weight of the catalyst, - the phosphorus content, expressed as P2O5, is between 1% and 4% by weight, relative to the total weight of the catalyst.

5. The hydroprocessing process according to claim 4, wherein the second catalyst is characterized by: - a nickel content expressed as NiO of 1.3% to 4.3% by weight relative to the total weight of the catalyst, - a tungsten content expressed as WO3 of 17 to 31% by weight relative to the total weight of the catalyst, The phosphorus content, expressed as P2O5, is preferably between 1.3% and 3.4% by weight, relative to the total weight of the catalyst.

6. The hydroprocessing method according to claim 5, wherein the second catalyst further has the following characteristics: -Ni / W molar ratio is 0.18 to 0.45 mol / mol, - The P / W molar ratio is 0.18 to 0.45 mol / mol.

7. The hydroprocessing process according to any one of the preceding claims, wherein the silica content in the support of the second catalyst is from 10% to 50% by weight relative to the total weight of the support.

8. The hydrotreatment process according to claim 1 , wherein the first catalyst has a molybdenum content, expressed as MoO 3 , ranging from 5% to 40% by weight, relative to the total weight of the catalyst, and a nickel content, expressed as NiO, ranging from 1% to 10% by weight, relative to the total weight of the catalyst.

9. The hydrotreatment process according to claim 1, wherein the first catalyst also comprises phosphorus in an amount ranging from 0.1% to 20% by weight relative to the total weight of the catalyst, expressed as P2O5.

10. The hydrotreatment process according to any of the preceding claims, wherein the first catalyst also contains oxygen-containing and / or nitrogen-containing and / or sulfur-containing organic compounds.

11. The hydrotreatment process according to claim 1 , wherein the organic compound is selected from compounds comprising one or more chemical functional groups selected from carboxyl, alcohol, thiol, thioether, sulfone, sulfoxide, ether, aldehyde, ketone, ester, carbonate, amine, nitrile, imide, oxime, urea or amide functional groups, or a furan ring-containing compound or a sugar.

12. The hydroprocessing method according to claim 11, wherein the organic compound is selected from the group consisting of 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, di(C1-C4 alkyl) succinate, and more specifically dimethyl succinate, dimethylformamide, 1-methyl-2-pyrrolidone, propylene carbonate, 2-methoxyethyl 3-oxobutyrate, N-bis(hydroxyethyl)glycine, tris(hydroxymethyl)methylglycine, 2-furancarboxaldehyde (also known as furfural), 5-hydroxymethylfurfural, 2-acetylfuran, 5-methyl-2 -furfural, ascorbic acid, butyl lactate, ethyl lactate, butyl butyrolactate, ethyl 3-hydroxybutyrate, ethyl 3-ethoxypropionate, 2-ethoxyethyl acetate, 2-butoxyethyl acetate, 2-hydroxyethyl acrylate, 1-vinyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, 1,5-pentanediol, 1-(2-hydroxyethyl)-2-pyrrolidone, 1-(2-hydroxyethyl)-2,5-pyrrolidinedione, 5-methyl-2(3H)-furanone, 1-methyl-2-piperidone, 4-aminobutyric acid, butyl glycolate, ethyl 2-mercaptopropionate, ethyl 4-oxopentanoate, diethyl maleate, dimethyl maleate, dimethyl fumarate, diethyl fumarate, dimethyl adipate and dimethyl 3-oxoglutarate.

13. The hydroprocessing method according to any one of claims 10 to 12, wherein the content of the organic compound is 1 wt% to 30 wt% relative to the total weight of the catalyst.

14. The hydrotreatment process according to any of the preceding claims, wherein the first catalyst and / or the second catalyst is at least partly based on sulfur.

15. The hydrotreatment process according to claim 1, which is carried out as a pretreatment in a fluidized catalytic cracking process.

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

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