METHOD FOR PREPARING A CATALYST COMPRISING BORON-DOPED ALUMINUM WITH THE ADDITION OF BORINE BY IMPREGNATION

Abstract

The present invention relates to the preparation of a catalyst with a specific organic additive comprising a support based on a mesoporous alumina containing boron, into which the boron precursor is introduced by impregnation onto said alumina, which has previously undergone a hydrothermal treatment step. This catalyst, comprising a support based on a boron-containing alumina, can, due to its advantageous properties, be used in all refining processes as well as an adsorbent, particularly for catalytic processes treating hydrocarbon fractions such as the vacuum hydrotreating of distillates.

Description

Title of the invention: METHOD FOR PREPARING A CATALYST COMPRISING A DOPED ALUMINUM BORON WITH ADDITION OF BORON BY IMPREGNATION technical field

[0001] The present invention relates to the preparation of a catalyst comprising a support based on a mesoporous alumina containing boron in which at least one boron precursor is added in the impregnation step to form a boron-doped alumina and in which specific organic additives are added to said catalyst.

[0002] Said catalyst, comprising a boron-containing alumina-based support, due to its advantageous properties, can be used in all refining processes as well as as an adsorbent, particularly for catalytic processes treating hydrocarbon fractions such as vacuum hydrotreating of distillates. Prior art

[0003] Patent CN112717948B describes a boron-modified hydrotreating catalyst, as well as a method for preparing and using this catalyst in a hydrotreating process. The boron-modified hydrotreating catalyst prepared according to this method exhibits greatly improved hydrodeazotation and aromatic saturation performance. In the described preparation process, boron is introduced by impregnation of alumina in the form of an aminoborane selected from dimethylaminoborane, trimethylaminoborane, ethylenediamineborane complex, triethylamineborane complex, and borane-N,N-dimethylaniline complex. The resulting catalyst has a total acid content of between 0.2 and 1 mmol / g as measured by NH3-TPD.The proportion of weak acids with an NH3 desorption temperature below 300 °C is 40%–90%, preferably 60%–75%, and the proportion of moderately strong acids with an NH3 desorption temperature of 300 °C–400 °C is 5%–40%. The specific surface area of ​​the catalyst is 120–320 m² / g, and the pore volume is 0.40–0.60 ml / g. Based on the weight of the final catalyst, the Group VIB metal content is 5.0–33.0%. The Group VIII metal content, based on the metal oxide, is 1.0–15.0%, and the boron mass fraction, based on the B₂O₃ content, is 0.2%–6.0%.

[0004] Patent CN103055909 B describes a hydrodesulfurization catalyst for LCO (Light Cycle Oil, or light gas oils from a catalytic cracking unit), as well as a method of preparation. The catalyst comprises the the following components in percentage by weight: a) a composite support of 67.0 to 97.0%; and B) at least one of CoO or NiO of 1.0 to 8.0% c) 2.0 to 25.0% MoO3; wherein the composite support comprises the following components in percentage by weight: a) 82.0 to 99.8% Al2O3; b) 0.10 to 8.0% B2O3 introduced by impregnation onto the alumina of a boron source selected from boric acid, trimethyl borate and ammonium borate; c) 0.10 to 10.0% P2O5.

[0005] Patent CN1083475C describes a hydrotreating catalyst and a method for its preparation. The catalyst uses Al₂O₃ as a support, preferably a γ-Al₂O₃ support, Group VIII metal oxides (nickel and / or cobalt oxide, with a content of 2 to 10 wt%) and Group VIB metal oxides (molybdenum oxide and / or tungsten oxide, with a content of 5 to 35 wt%) as active components, and contains additives B and P. The boron content is 0.5 wt% to 10 wt% (calculated as oxide), and the phosphorus content is 0.5 wt% to 10 wt% (calculated as oxide). The patent indicates that the boron is added in co-impregnation with the metal oxides in the impregnation solution.The total pore volume measured by the nitrogen adsorption method is between 0.1 and 0.50 ml / g, the average pore volume is between 2 and 10 nm, the pore volume between 5 and 10 nm represents at least 75% of the total pore volume, and the pore volume greater than 10 nm represents at least 5% of the total pore volume. The lateral compressive strength is 18 to 30 N / mm.

[0006] Patent WO201136862 describes a method for manufacturing a hydrotreating catalyst and a hydrotreating method for a hydrocarbon oil.The catalyst is loaded with one element from group 6 (chromium, molybdenum, or tungsten) and one element from group 8 to 10 (iron, cobalt, or nickel) of the periodic table, and an organic additive selected from polyhydric alcohols, saccharides, carboxylic acids, amino acids, and chelating agents, comprising the following steps: deposition of a boron compound onto the pore surface of an inorganic porous support composed mainly of alumina; calcination to obtain a boron-loaded intermediate product; addition of at least one of the group 6 elements from the periodic table at a concentration of 10 to 40% by mass relative to the mass of the oxide catalyst; at least one of the group 8 to 10 elements from the periodic table at a concentration of 0.5 to 20% by mass relative to the mass of the oxide catalyst; and an organic additive at a concentration of 0.15 to 3 times the total moles of the group 6 element and the element from the periodic table. group 8 to 10 of the periodic table, respectively, and drying.The catalyst is additively treated with a molar ratio of between 0.3 and 3 of the total metals from groups 6 and 8.

[0007] Patent JP4938178 B describes the chaining of catalysts in a process for hydrotreating in which one of the catalysts contains boron. The catalyst uses a support containing boron and having a boron / alumina mass ratio between 0.01 and 0.08. The catalyst contains 1 to 6% by mass of nickel, 10 to 30% by mass of molybdenum and 1 to 5% by mass of phosphorus in terms of oxide added by impregnation. Summary and significance of the invention

[0008] The present invention relates to a process for preparing a catalyst comprising at least one metal from group VIB and at least one metal from group VIII of the periodic table, at least one organic additive selected from dimethyl succinnate, gamma valerolactone, succinic acid and citric acid, alone or in mixture, and optionally at least one dopant selected from boron, phosphorus and silicon and preferably phosphorus and a support comprising alumina containing boron, said process comprising at least the following steps and preferably consisting of the following steps: a. A heat treatment step of alumina at a temperature between 500 and 1000°C, and for a duration of between 1 and 12 hours in the presence of an air stream containing between 5 and 50% by mass, and preferably between 5 and 45% by mass, and preferably between 5 and 40% by volume of water, b. At least one boron impregnation step, by adding at least one boron precursor selected from boron oxide, disodium tetraborate, orthoboric acid, disodium tetraborate decahydrate, disodium tetraborate pentahydrate, sodium perborate, perboric acid, sodium peroxometaborate, perboric acid, anhydrous disodium octaborate, disodium octaborate tetrahydrate, ammonium biborate, alone or in mixture, to the alumina obtained from step a), to obtain alumina containing boron, c. Optionally, a drying step of the boron-containing alumina obtained in step b) of impregnation, carried out at a temperature between 20 and 200°C and for a duration between 1 hour and 3 weeks to obtain dried boron-containing alumina, d. A calcination step of the boron-containing alumina obtained in step b) or possibly in step c) if step c) is implemented, at a temperature between 450 and 1000°C, and for a duration between 1 and 12 hours to obtain a boron-containing alumina support, e. Optionally, a heat treatment step of the boron-containing alumina support obtained in step d) at a temperature between 500 and 1000°C, and for a duration of between 1 and 12 hours in the presence of a airflow containing between 5 and 50% by mass, and preferably between 5 and 45% by mass, and preferably between 5 and 40% by volume of water, f. one or more boron-containing alumina support impregnation steps obtained in step d) or optionally in step e) if step e) is / are carried out, with at least one metal precursor from group VIB and / or at least one metal precursor from group VIII of the periodic table of elements, at least one organic additive selected from dimethyl succinnate, gamma valerolactone, succinic acid and citric acid, alone or in mixture and optionally at least one dopant selected from boron, phosphorus and silicon and preferably phosphorus, g. a drying step of the catalyst obtained at the end of step f) carried out at a temperature between 20 and 200°C preferably between 40 and 150°C and for a period of between 1 hour and 3 weeks and preferably between 1 hour and 48 hours to obtain the dried catalyst.

[0009] The process according to the present invention allows obtaining a catalyst based on a support comprising an alumina containing boron, the boron precursor being introduced by impregnation on said alumina, having textural properties suitable for its use as a catalyst support.

[0010] Another object of the present invention is a hydrotreating process for feedstocks selected from hydrocarbon fractions having a distillation range between 250°C and 600°C, preferably vacuum distillates, and renewable feedstocks selected from vegetable oils, algal oils, cooking oils, animal fats, fresh or used, alone or in mixtures, and feedstocks from the reprocessing of biomass and / or plastics and / or tires and / or household waste, alone or in mixtures, said process employing a catalyst comprising at least one metal from Group VIII, and / or at least one metal from Group VIB of the periodic table of elements, at least one organic additive selected from dimethyl succinnate, gamma valerolactone, succinic acid and citric acid, alone or in mixtures, and optionally at least one dopant selected from boron,phosphorus and silicon, and preferably phosphorus and an alumina comprising boron, said catalyst being prepared according to the preparation process of the invention.

[0011] An advantage of the invention is that it provides a new method for preparing a catalyst based on an alumina support containing boron, the boron precursor being introduced by impregnation onto said alumina. In particular, the method according to the invention does not involve autoclaving, and each of the steps unit costs of the process are economically attractive and already proven on industrial scales.

[0012] Finally, another advantage of the preparation process according to the invention is to allow the obtaining of catalysts exhibiting unparalleled performance compared to catalysts containing or not containing boron described in the prior art.In particular, the hydrotreating activity of feeds selected from hydrocarbon fractions having a distillation range between 250°C and 600°C and renewable feeds selected from vegetable oils, algal oils, cooking oils, animal fats, fresh or used, alone or in mixtures, and feeds from the reprocessing of biomass and / or plastics and / or tires and / or household waste, alone or in mixtures, and in particular the hydrotreating of vacuum distillate fractions of said catalyst prepared according to the invention in which the boron precursor is added by impregnation of an alumina support, is significantly superior to that of catalysts containing or not containing boron, prepared according to any prior art method known to those skilled in the art.

[0013] In the following text, the groups of chemical elements are given according to the CAS classification (CRC Handbook of Chemistry and Physics, publisher CRC Press, editor-in-chief DR Lide, 81st edition, 2000-2001). For example, group VIII according to the CAS classification corresponds to the metals of columns 8, 9 and 10 according to the new IUP AC classification, and group VIB to the metals of column 6.

[0014] In the following text, the expressions "between ... and ..." and "between ... and ..." are equivalent and mean that the limit values ​​of the interval are included in the range of values ​​described. If this were not the case and the limit values ​​were not included in the range described, such clarification will be provided by the present invention.

[0015] In the present description, the expression "greater than..." is understood as strictly greater than, and symbolized by the sign ">", and the expression "less than" as strictly less than, and symbolized by the sign "<".

[0016] In the sense of the present invention, the different embodiments presented can be used alone or in combination with each other, without limitation of combination.

[0017] In the sense of the present invention, the different parameter ranges for a given step, such as pressure ranges and temperature ranges, can be used alone or in combination. For example, in the sense of the present invention, a preferred range of pressure values ​​can be combined with a more preferred range of temperature values. Definitions and measurement methods.

[0018] The alumina comprising the boron of the present invention has a specific pore distribution, where the macroporous and mesoporous volumes are measured by mercury intrusion and the microporous volume is measured by nitrogen adsorption.

[0019] By "macropores" we mean pores whose opening is greater than 50 nm.

[0020] By "mesopores", we mean pores whose opening is between 2 nm and 50 nm, inclusive.

[0021] By "micropores" we mean pores whose opening is strictly less than 2 nm.

[0022] In the following description of the invention, the pore distribution measured by mercury porosimetry is determined according to ASTM D4284-83 at a maximum pressure of 4000 bar (400 MPa), using a surface tension of 484 dyne / cm and a contact angle of 140°. The wetting angle was taken to be 140° following the recommendations of the book "Techniques de l'ingénieur, traité analyse et caractérisation, P 1050-5, written by Jean Charpin and Bernard Rasneur".

[0023] The value from which mercury fills all intergranular voids is set at 0.2 MPa, and beyond this is considered that mercury penetrates the pores of alumina.

[0024] In order to obtain better accuracy, the value of the total pore volume corresponds to the value of the total pore volume measured by mercury porosimetry on the sample less the value of the total pore volume measured by mercury porosimetry on the same sample for a pressure corresponding to 30 psi (approximately 0.2 MPa).

[0025] The macroporous volume is defined as the cumulative volume of mercury introduced at a pressure between 0.2 MPa and 30 MPa, corresponding to the volume contained in pores with an apparent diameter greater than 50 nm.

[0026] The mesoporous volume is defined as the cumulative volume of mercury introduced at a pressure between 30 MPa and 400 MPa, corresponding to the volume contained in pores with an apparent diameter between 3.6 and 50 nm.

[0027] The volume of the micropores is measured by nitrogen porosimetry. The quantitative analysis of the microporosity is carried out using the "t" method (Lippens-De Boer method, 1965) which corresponds to a transform of the initial adsorption isotherm as described in the book "Adsorption by powders and porous solids. Principles, methodology and applications" written by F. Rouquérol, J. Rouquérol and K. Sing, Academie Press, 1999.

[0028] The average diameter of the mesopores (Dp in nm) is also defined as a diameter such that all pores smaller than this diameter constitute 50% of the mesoporous volume, measured by mercury porosimetry.

[0029] The pore distribution measured by nitrogen adsorption was determined by the Barrett-Joyner-Halenda (BJH) model. The nitrogen adsorption-desorption isotherm The BJH model is described in the periodical "The Journal of American Society", 73, 373, (1951) written by E.P. Barrett, L.G. Joyner and P.P. Halenda. In the following description of the invention, the nitrogen adsorption volume is understood to be the volume measured for P / Po = 0.99, the pressure at which it is assumed that nitrogen has filled all the pores.

[0030] In the following description of the invention, specific surface area means the specific surface area BET determined by nitrogen adsorption in accordance with ASTM D 3663-78 established from the BRUNAUER-EMMETT-TELLER method described in the periodical "The Journal of American Society", 60, 309, (1938).

[0031] X-ray diffraction on boehmite gels was carried out using the classical powder method with a diffractometer.

[0032] The Scherrer formula is a formula used in X-ray diffraction on polycrystalline powders or samples that relates the full width at half maximum (FWHM) of the diffraction peaks to the size of the crystallites. It is described in detail in the reference: Appl. Cryst. (1978). 11, 102-113 Scherrer after sixty years: A survey and some new results in the determination of crystallite size, J.I. Langford and A.J.C. Wilson. Description of the invention Step a) of heat treatment of alumina

[0033] According to the invention, said process for preparing the catalyst according to the invention comprising at least one metal from group VIB and at least one metal from group VIII of the periodic table, at least one organic additive selected from dimethyl succinnate, gamma valerolactone, succinic acid and citric acid, alone or in mixture, and optionally at least one dopant selected from boron, phosphorus and silicon and preferably phosphorus and a support comprising a boron-containing alumina includes a step a) of heat treatment of an alumina at a temperature between 500 and 1000°C, and for a period of between 1 and 12 hours in the presence of an air stream containing between 5 and 50% by mass, and preferably between 5 and 45% by mass, and preferably between 5 and 40% by volume of water.

[0034] The alumina used according to the invention is preferably a shaped alumina and preferably in the form of irregular and non-spherical balls, extrudates, pellets or agglomerates whose specific shape can result from a crushing step and preferably in the form of extrudates.

[0035] Preferably, said alumina is in the form of extrudates having a diameter of between 0.8 and 3 mm, preferably between 1.2 and 2.6 mm. The geometry of the extrudates may be cylindrical, trilobular, quadrilobular or any other advantageous shape depending on the desired application.

[0036] Preferably, the alumina used according to the invention is an alumina r|, ô or y and preferably an alumina y.

[0037] Preferably, said alumina is a non-mesostructured mesoporous alumina.

[0038] Preferably, said mesoporous alumina is devoid of micropores. The absence of micropores is measured and verified by nitrogen adsorption.

[0039] Preferably, said mesoporous alumina is devoid of macropores. The absence of macropores is measured and verified by mercury porosimetry.

[0040] Said alumina may be any commercial conventional alumina prepared according to conventional preparation methods of the prior art, such as co-precipitation.

[0041] Preferably, said alumina is prepared according to a preparation process comprising and preferably consisting of:

[0042] A1) at least one or more precipitation step(s) of a boehmite gel, in an aqueous reaction medium, by the simultaneous addition of at least one basic precursor selected from sodium aluminate, potassium aluminate, ammonia, sodium hydroxide and potassium hydroxide and at least one acidic precursor selected from aluminum sulfate, aluminum chloride, aluminum nitrate, sulfuric acid, hydrochloric acid, and nitric acid, wherein at least one of the basic or acid precursors comprises aluminum, the relative flow rate of the acid and basic precursors is selected so as to obtain a pH of the reaction medium between 8.9 and 10.0 and the flow rate of the aluminum-containing acid and basic precursor(s) is adjusted so as to obtain an advancement rate of said first step between 15 and 100% and preferably between 17 and 100%,the rate of advancement being defined as the proportion of boehmite gel formed in A12O3 equivalent during said first precipitation step relative to the total quantity of boehmite gel formed in A12O3 equivalent at the end of the or each of the precipitation steps implemented, said precipitation step operating at a temperature between 20 and 80°C, and for a duration between 2 minutes and 30 minutes, ,

[0043] B1) possibly one or more heat treatment step(s) of the suspension obtained at the end of step A1) at a temperature between 70 and 100°C for a period between 30 minutes and 5 hours,

[0044] Cl) a filtration step of the suspension obtained at the end of step Al) or possibly at the end of step Bl) of heat treatment, followed by at least one washing step of the boehmite gel obtained,

[0045] Dl) ​​a drying step of the boehmite gel obtained at the end of step Cl) to obtain a powder,

[0046] El) a step of shaping the powder obtained at the end of step Dl) to obtain the raw material,

[0047] Fl) a drying step of the raw material obtained in the shaping step El) carried out at a temperature between 20 and 200°C and for a duration between 1 hour and 3 weeks to obtain the dried raw material

[0048] Gl) a heat treatment step of the dried raw material obtained at the end of step Fl) at a temperature between 500 and 1000°C, and for a duration between 1 and 12 hours in the presence of a dry air flow allowing the transition of boehmite to the final alumina, and allowing adjustment of the final porous texture of the alumina.

[0049] According to the invention, said alumina is subjected to a step a) of heat treatment at a temperature between 500 and 1000°C, for a period of between 1 and 12 h, in the presence of an airflow containing between 5 and 50% mass, and preferably between 5 and 45% mass, and preferably between 5 and 40% mass by volume of water.

[0050] Preferably, said heat treatment step a) operates at a temperature between 520 and 850°C, preferably between 520 and 800°C and even more preferably between 530 and 750°C.

[0051] Preferably, said heat treatment step a) operates for a duration between 1h and 12h, preferably between 1h30 and 10h and even more preferably between 2h and 8h.

[0052] Step a) of the process according to the invention provides mesoporous alumina with controlled mesoporosity, good thermal and chemical stability, a centered, uniform, and controlled mesopore size distribution, and a calibrated specific surface area and pore volume, particularly mesoporous volume, suitable for use as a catalyst support. Step b) boron impregnation

[0053] According to the invention, at least one boron impregnation step, by adding at least one boron precursor selected from boron oxide, disodium tetraborate, orthoboric acid, disodium tetraborate decahydrate, disodium tetraborate pentahydrate, sodium perborate, perboric acid, sodium peroxometaborate, perboric acid, anhydrous disodium octaborate, disodium octaborate tetrahydrate, ammonium biborate, alone or in mixture, is carried out on the hydrothermally treated alumina from step a).

[0054] Preferably, an impregnation step is carried out with an impregnation solution containing at least one boron precursor.

[0055] Preferably, the boron precursor is chosen from disodium tetraborate, orthoboric acid, disodium tetraborate decahydrate, disodium tetraborate pentahydrate, ammonium biborate and preferably ammonium biborate.

[0056] Preferably, the boron impregnation step is carried out by dry impregnation, excess impregnation or exchange impregnation and preferably by dry impregnation.

[0057] The quantity of boron precursor added in step b) is advantageously adjusted so that the alumina obtained at the end of step b) comprises a content of the element Bore between 0.1 and 10% by weight, preferably between 0.1 and 9% by weight and even more preferably between 0.1 and 4% by weight, relative to the total weight of said alumina in A12O3 equivalent. Optional drying step c)

[0058] The boron-containing alumina obtained after step b) of impregnation may advantageously be subjected to a drying step. This drying step is advantageously carried out at a temperature between 20 and 200°C, preferably between 40 and 150°C, and for a duration of between 1 hour and 3 weeks, and preferably between 1 hour and 48 hours, to obtain dried boron-containing alumina. Step d) of calcination

[0059] According to the invention, the boron-containing alumina obtained in step b) or possibly in step c) in the case where step c) is implemented, then undergoes a calcination step d) at a temperature between 450 and 1000°C, for a period of between 1 and 12 h, to obtain a boron-containing alumina support.

[0060] Preferably, said calcination step d) is carried out in the presence of a dry air stream not containing water.

[0061] Preferably, said calcination step d) is carried out at a temperature between 450 and 850°C, preferably between 450 and 800°C and even more preferably between 450 and 750°C.

[0062] Preferably, said calcination step d) is carried out for a period of between 1h and 12h, preferably between 1h30 and 100 and even more preferably between 2h and 8h.

[0063] Said calcination step d) allows adjustment of the final porous texture of the boron-containing alumina used as a support for the catalyst according to the invention.

[0064] The boron content expressed as oxide in the material and preferably the alumina obtained at the end of step c) is preferably between 0.1 and 10% by weight, more preferably between 0.1 and 9% by weight and even more preferably between 0.1 and 4% by weight, relative to the total weight of said alumina in A12O3 equivalent.

[0065] At the end of step d) of calcination of the preparation process according to the invention, a mesoporous alumina containing boron and exhibiting controlled mesoporosity is obtained, exhibiting good thermal and chemical stability, and having a distribution in centered, uniform and controlled mesopore size, and a specific surface area and porous volume, and in particular mesoporous calibrated and adapted for its use as a catalyst support.

[0066] Said mesoporous alumina containing boron obtained at the end of step d) is preferably free of micropores. The absence of micropores is measured and verified by nitrogen adsorption.

[0067] Said mesoporous alumina containing boron obtained at the end of step d) is preferably free of macropores. The absence of macropores is measured and verified by mercury porosimetry.

[0068] The mesoporous alumina containing boron obtained at the end of step d) advantageously has a specific surface area BET of between 50 and 450 m2 / g, preferably between 100 and 400 m2 / g, preferably between 200 and 400 m2 / g, and most preferably between 220 and 380 m2 / g, and a mesoporous volume greater than or equal to 0.5 ml / g, preferably between 0.55 and 0.85 ml / g, most preferably between 0.60 and 0.80 ml / g and even more preferably between 0.65 and 0.78 ml / g.

[0069] Preferably, the total porous volume of said boron-containing alumina measured by mercury porosimetry is between 0.6 and 0.9 ml / g.

[0070] Preferably, the percentage of the mesoporous volume of pores having a diameter between 8 and 20 nm measured by mercury porosimetry is between 60 and 100%, preferably it is between 65 and 100%.

[0071] The average diameter of the mesopores measured by mercury porosimetry of said boron-containing alumina, determined by volume, is advantageously between 7 and 13.5 nm and preferably between 8.5 and 12.5 nm, most preferably between 9.0 and 12.3 nm, even more preferably between 9.5 and 12.0 nm.

[0072] Preferably, the boron-containing alumina obtained at the end of step d) is in the form of irregular and non-spherical beads, extrudates, pellets or agglomerates whose specific shape may result from a crushing step.

[0073] The boron-containing alumina obtained at the end of step d) is used as a support for the catalyst prepared according to the invention. The form of the support comprising the boron-containing alumina is that of extrudates with a diameter of between 0.8 and 3 mm, preferably between 1.2 and 2.6 mm. The geometry of the extrudates may be cylindrical, trilobular, quadrilobular, or any other advantageous shape depending on the desired application. Optional heat treatment step e).

[0074] The boron-containing alumina support obtained in step d) can advantageously be subjected to a heat treatment step and preferably to a treatment step hydrothermal carried out at a temperature between 500 and 1000°C, and for a duration between 1 and 12 hours in the presence of an air flow containing between 5 and 50% mass, and preferably between 5 and 45% mass, and preferably between 5 and 40% mass by volume of water.

[0075] Preferably, said heat treatment step e) operates at a temperature between 520 and 850°C, preferably between 520 and 800°C and even more preferably between 530 and 750°C.

[0076] Preferably, said heat treatment step e) operates for a duration between 1h and 12h, preferably between 1h30 and 100 and even more preferably between 2h and 8h. Step f) of impregnation.

[0077] According to the invention, one or more step(s) f) of impregnating the boron-containing alumina support obtained in step d) or optionally in step e) in the case where step e) is carried out, with at least one metal from group VIII and / or at least one metal from group VIB of the periodic table of elements, at least one organic additive selected from dimethyl succinnate, gamma valerolactone, succinic acid and citric acid, alone or in mixture and optionally a doping element selected from boron, phosphorus and silicon and preferably phosphorus, is(s) carried out.

[0078] Preferably, the said steps f) of impregnation are carried out by means of the implementation of one or more aqueous impregnation solution(s) containing the precursor(s) of each of the components of the active phase of the catalyst.

[0079] The metal(s) of group VIII and / or at least one metal of group VIB and optionally a dopant element chosen from boron, phosphorus, and silicon, and preferably phosphorus, can advantageously be introduced in one or more steps, preferably by dry or excess impregnation. Preferably, the metal(s) and the dopant are introduced in the same impregnation step.

[0080] In a first preferred embodiment, at least one metal from Group VIII, at least one metal from Group VIB, and at least one phosphorus dopant are deposited on said support in a first impregnation step h). This first impregnation step is followed by a drying step and then a second impregnation step h) of at least one organic additive selected from dimethyl succinnate, gamma valerolactone, succinic acid, and citric acid, alone or in a mixture. A final drying step is also advantageously carried out after the impregnation of the organic additive.

[0081] In a second embodiment, a single impregnation solution containing at least one metal from group VIII, at least one metal from group VIB, at least one phosphorus dopant and an organic additive selected from succinnate dimethyl, gamma valerolactone, succinic acid and citric acid, alone or in mixture, is used to impregnate said support in a single impregnation step.

[0082] The group VIB metal present in the active phase of the catalyst is preferably chosen from molybdenum and tungsten. The group VIII metal present in the active phase of the catalyst is preferably chosen from cobalt, nickel, and mixtures of these two elements. The active phase of the catalyst is preferably chosen from the group formed by the combination of nickel-molybdenum, cobalt-molybdenum, nickel-tungsten, nickel-molybdenum-tungsten, and nickel-cobalt-molybdenum, and most preferably the active phase consists of nickel and molybdenum, nickel and tungsten, or a nickel-molybdenum-tungsten combination.

[0083] The content of group VIII metal in the catalyst is less than 20% by weight, preferably between 0.03 and 15% by weight, most preferably between 0.5 and 10% by weight, and even more preferably between 1 and 8% by weight expressed as group VIII metal oxide relative to the total weight of the catalyst.

[0084] The content of metal of group VIB in the catalyst is between 1 and 50% by weight, preferably between 5 and 40% by weight, and more preferably between 10 and 35% by weight and even more preferably between 15 and 30% by weight expressed as metal oxide of group VIB relative to the total weight of the catalyst.

[0085] The molar ratio of group VIII metal to group VIB metal of the catalyst is generally less than 1, preferably between 0.01 and 0.75, and most preferably between 0.10 and 0.60 and even more preferably between 0.20 and 0.50.

[0086] Optionally, the catalyst may also have a phosphorus content generally less than 15% by weight, preferably between 0.1 and 10% by weight, most preferably between 0.1 and 8% by weight, and even more preferably between 0.2 and 6% by weight of P2O5 relative to the total weight of fresh catalyst.

[0087] Furthermore, in the case where the catalyst includes phosphorus, the phosphorus / (metal of group VIB) molar ratio is generally between 0.02 and 1, preferably between 0.04 and 0.8, and most preferably between 0.1 and 0.75.

[0088] According to the invention, at least one organic additive selected from dimethyl succinnate, gamma valerolactone, succinic acid and citric acid, alone or in mixture, is introduced onto said support in step f). Preferably, the organic additive is dimethyl succinnate.

[0089] The content of organic additive(s) containing oxygen and / or nitrogen and / or sulfur on the catalyst is between 1 and 30% by weight, preferably between 1.5 and 25% by weight, and more preferably between 2 and 20% by weight relative to the total weight of the fresh catalyst. The organic compound(s) introduced during one of the catalyst preparation steps are introduced in a quantity corresponding to:

[0090] - to a compound molar ratio added by metal(s) of group VIB present(s) in the catalyst having a concentration between 0.01 and 2.0 mol / mol, preferably between 0.01 and 1.5 mol / mol, most preferably between 0.01 and 1.0 mol / mol, and most preferably between 0.02 and 0.8 mol / mol,

[0091] - and to a compound molar ratio added by group VIII metal(s) present in the catalyst between 0.02 and 6.0 mol / mol, preferably between 0.03 and 4.0 mol / mol, preferably between 0.04 and 3.0 mol / mol, and most preferably between 0.05 and 0.4 mol / mol.

[0092] When several additives are present, the different molar ratios are added together so that the sum of the additives added corresponds to the values ​​above. Step g) of drying

[0093] According to the invention, the catalyst obtained at the end of step f) is dried in a drying step g) carried out at a temperature between 20 and 200°C preferably between 40 and 150°C and for a period of between 1 hour and 3 weeks and preferably between 1 hour and 48 hours to obtain a dried catalyst.

[0094] Preferably, said catalyst obtained in step g) does not undergo a final calcination step, i.e. the impregnated catalytic precursor has not been subjected to a heat treatment step at a temperature above 200°C under an inert atmosphere or under an atmosphere containing oxygen, in the presence of water or not.

[0095] Another object of the present invention is a hydrotreating process for hydrocarbon cuts using a catalyst containing an alumina comprising boron, said alumina being prepared according to the preparation process according to the invention.

[0096] In particular, another object of the present invention is a hydrotreating process for feedstocks selected from hydrocarbon fractions having a distillation range between 250°C and 600°C, preferably vacuum distillates, and renewable feedstocks selected from vegetable oils, algal oils, cooking oils, animal fats, fresh or used, alone or in mixtures, and feedstocks from the reprocessing of biomass and / or plastics and / or tires from / out of household waste, alone or in mixtures, said process employing a catalyst comprising at least one metal from Group VIII and / or at least one metal from Group VIB of the periodic table of elements, optionally at least one dopant selected from boron, phosphorus, and silicon, and preferably phosphorus and optionally at least one organic additive selected from dimethyl succinnate, gamma valerolactone, succinic acid and citric acid, alone or in mixture and a support comprising an alumina comprising boron, said catalyst being prepared according to the preparation process according to the invention.

[0097] Before its use in a hydrotreating process for hydrocarbon fractions, the catalyst is generally subjected to sulfidation in order to obtain the metals in their sulfided or partially sulfided forms as described below. This activation or sulfidation step is carried out by methods well known to those skilled in the art, and advantageously under a sulfur-reducing atmosphere in the presence of hydrogen and hydrogen sulfide.

[0098] Said catalyst is advantageously sulfided ex situ or in situ. The sulfiding agents are H2S gas, elemental sulfur, CS2, mercaptans, sulfides and / or polysulfides, hydrocarbon fractions with a boiling point below 400°C containing sulfur compounds, or any other sulfur-containing compound used for activating hydrocarbon feedstocks for the purpose of sulfiding the catalyst. Said sulfur-containing compounds are advantageously selected from alkyl disulfides such as, for example, dimethyl disulfide (DMDS), alkyl sulfides such as, for example, dimethyl sulfide, thiols such as, for example, n-butylmercaptan (or 1-butanethiol), and polysulfide compounds of the tertiononyl polysulfide type. The catalyst can also be sulfided by the sulfur contained in the feedstock to be desulfurized. Preferably, the catalyst is sulfided in situ in the presence of a sulfurizing agent and a hydrocarbon feedstock.Preferably, the catalyst is sulfided in situ in the presence of a hydrocarbon feedstock with added dimethyl disulfide.

[0099] Preferably, the so-called heavy hydrocarbon feedstocks are chosen from those having a weighted average temperature (WAT) greater than 380°C. The WAT is defined from the temperatures at which 5%, 50%, and 70% of the feed volume distill, according to the following formula: WAT = (T 5% + 2 x T 50% + 4 x T 70%) / 7. The WAT is calculated from simulated distillation values. The WAT of the feedstock is greater than 380°C and preferably less than 600°C, and even more preferably less than 580°C.

[0100] According to the invention, the treated hydrocarbon feedstock preferably has a distillation range between 250°C and 600°C, preferably between 300 and 580°C.

[0101] Said hydrocarbon feedstock is advantageously chosen from LCOs or HCOs (Light Cycle Oil or Heavy Cycle Oil according to Anglo-Saxon terminology (light or heavy gas oils from a catalytic cracking unit), vacuum distillates, for example gas oils from the direct distillation of crude oil or from conversion units such as catalytic cracking, coking or visbreaking, feedstocks originating from aromatic extraction units, lubricating oil bases or from solvent dewaxing of lubricating oil bases, distillates from desulfurization or hydroconversion processes in fixed bed or bubbling bed of atmospheric residues and / or vacuum residues and / or deasphalted oils, or the feedstock may be a deasphalted oil.

[0102] Preferably, said hydrocarbon charge is a vacuum distillate.

[0103] Any hydrocarbon feed containing sulfur and nitrogen compounds that inhibit hydrotreating, and with a TMP similar to that of a vacuum distillate cut, can be used in the process of the present invention. The hydrocarbon feed can be of any chemical nature, that is to say, have any distribution among the different chemical families, in particular paraffins, olefins, naphthenes, and aromatics.

[0104] Said hydrocarbon feedstock comprises nitrogenous and / or sulfurous organic molecules. The nitrogenous organic molecules are either basic, such as amines, anilines, pyridines, acridines, quinolines and their derivatives, or neutral, such as pyrroles, indoles, carbazoles and their derivatives. It is primarily the basic nitrogenous molecules that inhibit hydrotreating catalysts, and in particular additive catalysts.

[0105] The nitrogen content is greater than or equal to 250 ppm, preferably between 400 and 10,000 ppm by weight, more preferably between 700 and 4,000 ppm by weight, and even more preferably between 1,000 and 4,000 ppm by weight. The basic nitrogen content comprises at least one-quarter of the total nitrogen content. The basic nitrogen content is generally greater than or equal to 60 ppm, more preferably between 175 and 1,000 ppm by weight, and even more preferably between 250 and 1,000 ppm.

[0106] The sulfur content in the feed is generally between 0.01 and 5% by weight, preferably between 0.2 and 4% by weight and even more preferably between 0.5 and 3% by weight.

[0107] Said hydrocarbon feedstock may advantageously contain metals, in particular nickel and vanadium. The cumulative nickel and vanadium content of said hydrocarbon feedstock, treated according to the hydrocracking process according to the invention, is preferably less than 1 ppm by weight.

[0108] The asphaltene content of said hydrocarbon filler is generally less than 3000 ppm, preferably less than 1000 ppm, even more preferably less than 200 ppm.

[0109] The processed feedstock generally contains resins, preferably with a resin content greater than 1 wt%, and more preferably greater than 5 wt%. The resin content is measured according to ASTM D 2007-11.

[0110] According to the invention, said feed treated in the hydrotreatment process is chosen from renewable feeds selected from vegetable oils, algal oils, cooking oils, animal fats, fresh or used, alone or in mixtures, and feeds from the reprocessing of biomass / plastics / tires / and household waste, alone or in mixtures.

[0111] Said charge treated according to the hydrotreating process of the invention may also be a mixture of said charges previously mentioned.

[0112] The catalyst prepared from the boron-containing alumina support according to the invention can then be used in one, two, or more reactors. It is generally used for implementation in a fixed bed.

[0113] The operating conditions used for the operation, preferably in a fixed bed, of the catalyst prepared from the alumina support containing boron according to the invention correspond to those generally used for a hydrotreating process and are as follows: the temperature is advantageously between 200 and 450°C, and preferably between 300 and 400°C, the pressure is advantageously between 0.5 and 30 MPa, and preferably between 5 and 20 MPa, the hourly volumetric velocity (defined as the ratio of the volumetric flow rate of charge to the volume of the catalyst per hour) is advantageously between 0.1 and 20 h 1 and preferably between 0.2 and 5 h 1 , and the hydrogen / charge ratio expressed in volume of hydrogen, measured under normal temperature and pressure conditions, per volume of liquid charge is advantageously between 50 1 / 1 and 2000 1 / 1.

[0114] The invention is illustrated by the following examples which are in no way limiting. Examples:

[0115] Example 1: according to the invention (0.5% boron in the intermediate product)

[0116] A catalyst A is prepared according to the following steps: water has been added to a pseudo-boehmite, which is a precursor of alumina, and the mixture was kneaded using a mixing machine for 30 minutes and molded by extrusion.

[0117] The resulting extrudate is calcined in dry air at 720°C for 1.5 hours, to obtain a gamma-alumina support with a specific surface area of ​​290 m2 / g, a pore volume of 0.73 ml / g and an average pore diameter of 9.5 nm.

[0118] The alumina obtained is then subjected to a step a) of hydrothermal treatment at 540°C for 2 hours in the presence of 20% volume of water to obtain a gamma-alumina support with a specific surface area of ​​210 m2 / g, a pore volume of 0.78 ml / g and an average pore diameter of 11.5 nm.

[0119] The alumina obtained is then impregnated (step b) with an aqueous solution of ammonium biborate by the pore-filling method, and the alumina impregnated is calcined (step d) in dry air at 550 °C for 1 hour to obtain an intermediate product loaded with boron with 0.5% by mass of boron relative to the total weight of said alumina in A12O3 equivalent.

[0120] In all examples, the intermediate product is understood to be the boron-containing alumina obtained after step d) of calcination.

[0121] The boron-containing alumina obtained after step d) of calcination is then impregnated in a step f) with an aqueous solution containing molybdenum trioxide, nickel hydroxide and phosphoric acid by the pore-filling method, so that the final catalyst A contains respectively 25% by mass of molybdenum trioxide, 6% by mass of nickel oxide and 6% by mass of phosphorus pentoxide on the basis of the mass of the oxide of the final catalyst.

[0122] The impregnated support is then air-dried at a temperature of 120°C for 2 hours, with the temperature of the impregnated support being maintained at 120°C. The catalyst is then additively treated by impregnation with a solution of the organic additive dimethyl succinate using the pore-filling method to obtain catalyst A, which is then dried (step g) at a temperature of 120°C for 2 hours. The physical properties and chemical composition of catalyst A are shown in Table 1.

[0123] Example 2: according to the invention (1.1% boron in the intermediate product)

[0124] A catalyst B is prepared according to the same method as in Example 1, except that the quantity of boron charged in the intermediate product is 1.1% by mass of boron relative to the total weight of said alumina in Al2O3 equivalent. The physical properties and chemical composition of catalyst B are shown in Table 1.

[0125] Example 3: according to the invention (2.6% boron in the intermediate product)

[0126] A catalyst C is prepared according to the same method as in Example 1, except that the quantity of boron charged on the intermediate product is 2.6% by mass of boron relative to the total weight of said alumina in Al2O3 equivalent. The physical properties and chemical composition of catalyst C are indicated in Table 1.

[0127] Example 4 not in accordance with the invention (1.1% boron in the intermediate product)

[0128] A non-conforming catalyst D is prepared according to the same method as in Example 2, except that catalyst D does not include impregnation with an organic additive. It is prepared according to the following steps: water was added to the pseudo-boehmite, and the mixture was kneaded using a mixing machine for 30 minutes and molded by extrusion.

[0129] The resulting extrudate is calcined in dry air at 720°C for 1.5 hours, to obtain a gamma-alumina support with a specific surface area of ​​290 m2 / g, a pore volume of 0.73 ml / g and an average pore diameter of 9.5 nm.

[0130] The alumina obtained is then subjected to a step a) of hydrothermal treatment at 540°C for 2 hours in the presence of 20% volume of water to obtain a gamma-alumina support with a specific surface area of ​​210 m2 / g, a pore volume of 0.78 ml / g and an average pore diameter of 11.5 nm.

[0131] The alumina obtained is then impregnated (step b) with an aqueous solution of ammonium biborate by the pore-filling method, and the impregnated alumina is calcined (step d) in dry air at 550°C for 1 hour to obtain an intermediate product loaded with boron with 1.1% by mass of boron relative to the total weight of said alumina in A12O3 equivalent.

[0132] The boron-containing alumina obtained after step d) of calcination is then impregnated in a step f) with an aqueous solution containing molybdenum trioxide, nickel hydroxide and phosphoric acid by the pore-filling method, so that the final catalyst A contains respectively 25% by mass of molybdenum trioxide, 6% by mass of nickel oxide and 6% by mass of phosphorus pentoxide on the basis of the mass of the oxide of the final catalyst.

[0133] The impregnated support is then air-dried at a temperature of 120°C for 2 hours, the temperature of the impregnated support being maintained at 120°C to obtain a catalyst D. The physical properties and chemical composition of catalyst D are shown in Table 1.

[0134] Example 5: not in accordance with the invention (1.1% boron on the final catalyst)

[0135] A catalyst E not conforming to the invention is prepared according to the same method as that of example 2 except that the alumina does not undergo hydrothermal treatment step a). It is prepared according to the following steps: water is added to the pseudo-boehmite, and the mixture was kneaded using a kneading machine for 30 minutes and molded by extrusion.

[0136] The resulting extrudate is calcined in dry air at 720°C for 1.5 hours, to obtain a gamma-alumina support with a specific surface area of ​​290 m2 / g, a pore volume of 0.73 ml / g and an average pore diameter of 9.5 nm.

[0137] The alumina obtained is then impregnated (step b) with an aqueous solution of ammonium biborate by the pore-filling method, and the impregnated alumina is calcined (step d) in dry air at 550°C for 1 hour to obtain an intermediate product loaded with boron with 1.1% by mass of boron relative to the total weight of said alumina in A12O3 equivalent.

[0138] The intermediate product is impregnated with an aqueous solution containing molybdenum trioxide, nickel hydroxide, and phosphoric acid by the pore-filling method, so that the finished catalyst contains 25% by mass of molybdenum trioxide, 6% by mass of oxide of nickel and 6% in niasse of phosphorus pentoxide based on the mass of the oxide of the final catalyst E.

[0139] The impregnated support is then dried at a temperature of 120°C for 2 hours, with the temperature of the impregnated support being maintained at 120°C. The catalyst is then additively treated by impregnation with a solution of the organic additive dimethyl succinate using the pore-filling method to obtain catalyst E. The physical properties and chemical composition of catalyst E are shown in Table 1.

[0140] Example 6: preparation of a catalyst F not according to the invention (1.1% boron on the final catalyst)

[0141] A non-conforming catalyst F is prepared according to the same method as in Example 2, except that the alumina does not undergo hydrothermal treatment step a) and the catalyst is not additively treated. It is prepared according to the following steps: water is added to the pseudo-boehmite, and the mixture is kneaded using a mixing machine for 30 minutes and molded by extrusion.

[0142] The resulting extrudate is calcined in dry air at 720°C for 1.5 hours, to obtain a gamma-alumina support with a specific surface area of ​​290 m2 / g, a pore volume of 0.73 ml / g and an average pore diameter of 9.5 nm.

[0143] The alumina obtained is then impregnated with an aqueous solution of ammonium biborate by the pore-filling method, and the impregnated alumina is calcined in air at 550°C for 1 hour to obtain an intermediate product loaded with boron with 1.1% by mass of boron relative to the total weight of said alumina in A12O3 equivalent.

[0144] The intermediate product is then impregnated with an aqueous solution containing molybdenum trioxide, nickel hydroxide and phosphoric acid by the pore-filling method, so that the final catalyst contains respectively 25% by mass of molybdenum trioxide, 6% by mass of nickel oxide and 6% by mass of phosphorus pentoxide on the basis of the mass of the oxide of the final catalyst.

[0145] The impregnated support is dried at a temperature of 120°C for 2 hours, the temperature of the impregnated support being maintained at 120°C to obtain a catalyst F. The physical properties and chemical composition of the catalyst F are indicated in Table 1.

[0146] Example 7: preparation of a G catalyst not according to the invention (no boron on the final catalyst)

[0147] A non-conforming G catalyst is prepared according to the following steps: water is added to the pseudo-boehmite, and the mixture is kneaded using a kneading machine for 30 minutes and molded by extrusion.

[0148] The resulting extrudate is calcined in dry air at 720°C for 1.5 hours, to obtain a gamma-alumina support with a specific surface area of ​​290 m2 / g, a pore volume of 0.73 ml / g and an average pore diameter of 9.5 nm.

[0149] The alumina obtained is then subjected to a step a) of hydrothermal treatment at 540°C for 2 hours in the presence of 20% volume of water to obtain a gamma-alumina support with a specific surface area of ​​210 m2 / g, a pore volume of 0.78 ml / g and an average pore diameter of 11.5 nm.

[0150] The gamma alumina support is impregnated with an aqueous solution containing molybdenum trioxide, nickel hydroxide and phosphoric acid by the pore-filling method, so that the final catalyst contains respectively 25% by mass of molybdenum trioxide, 6% by mass of nickel oxide and 6% by mass of phosphorus pentoxide on the basis of the mass of the oxide of the final catalyst.

[0151] The boron-containing support is dried at a temperature of 120°C for 2 hours, with the temperature of the impregnated support maintained at 120°C. The catalyst is then additively treated by impregnation with a solution of the organic additive dimethyl succinate using the pore-filling method to obtain catalyst G. The physical properties and chemical composition of catalyst G are shown in Table 1.

[0152] The catalysts thus obtained were then evaluated by hydrodeazotation of a distillate under vacuum with a TMP of 474°C (T5% = 389°C, T50% = 468°C, T70% = 498°C). The characteristics of the feed are as follows: sulfur 2.6 wt%, nitrogen 1350 ppm, basic nitrogen 392 ppm, resins 9.1 wt%.

[0153] The test is carried out in a flow-through fixed-bed isothermal pilot reactor, with the fluids flowing from bottom to top.

[0154] After in situ sulfidation at 350°C in the pressurized unit using the vacuum distillate of the test to which 2% by weight of dimethyl disulfide is added, the hydrotreating test was carried out under the following operating conditions: a total pressure of 160 bar (16 MPa), a WH of 1.5 h-1, an H2 / charge ratio of 1000 1 / h and a temperature of 370°C.

[0155] The following table shows the relative HDN percentage achieved in the reactor. The HDN percentage is calculated as follows: HDN (%) = (Nout - Nin) / Nin. The relative HDN % is normalized to a base of 100 corresponding to the reference case without boron.

[0156] [Tables 1] Catalysts A. B Compliant Compliant Non-compliant E Non-compliant Non-compliant Non-compliant 0.5 ■J 2.6 Li 1.1 1.1 0 Tailing Gui Yes Yes No No Qu; %MoO3 25 25 25 zo 25- 25 6: 6 S 6 6: o 6 Addi^f -cUl Ouf No Yes No Qu; 103 1.08 120 80 95 85 W

[0157] The above examples highlight the improved performance of a catalyst prepared according to the invention in which a small amount of boron of between 0.1 and 10% wt% preferably between 0.1 and 9% and preferably between 0.1 and 4% has been introduced by impregnation on the alumina support which has previously undergone a hydrothermal treatment step, combined with the additivation of the catalyst with specific organic additives according to the invention.

Claims

1. Demands A process for preparing a catalyst comprising at least one metal from Group VIB and at least one metal from Group VIII of the periodic table, at least one organic additive selected from dimethyl succinnate, gamma valerolactone, succinic acid, and citric acid, alone or in mixtures, and optionally at least one dopant selected from boron, phosphorus, and silicon, and preferably phosphorus, and a support comprising boron-containing alumina, said process comprising at least the following steps, and preferably consisting of the following steps: a) A heat treatment step of alumina at a temperature between 500 and 1000°C, for a duration of between 1 and 12 hours in the presence of an air stream containing between 5 and 50% by mass, and preferably between 5 and 45% by mass, and preferably between 5 and 40% by volume of water; b) At least one boron impregnation step.by adding at least one boron precursor selected from boron oxide, disodium tetraborate, orthoboric acid, disodium tetraborate decahydrate, disodium tetraborate pentahydrate, sodium perborate, perboric acid, sodium peroxometaborate, perboric acid, anhydrous disodium octaborate, disodium octaborate tetrahydrate, ammonium biborate, alone or in mixture, to the alumina obtained from step a), to obtain boron-containing alumina, c) Optionally, a drying step of the boron-containing alumina obtained in the impregnation step b), carried out at a temperature between 20 and 200°C and for a duration between 1 hour and 3 weeks to obtain dried boron-containing alumina, d) A calcination step of the boron-containing alumina obtained in the step b) or possibly in step c) if step c) is implemented, at a temperature between 450 and 1000°C,and for a period of between 1 and 12 hours to obtain an alumina support containing boron, e) Optionally a heat treatment step of the alumina support containing boron obtained in step d) at a temperature between 500 and 1000°C, and for a period of between,

2.

3.

4.

5.

6. 1 and 12 hours in the presence of an airflow containing between 5 and 50% by mass, and preferably between 5 and 45% by mass, and preferably between 5 and 40% by volume of water, f) one or more steps of impregnating the boron-containing alumina support obtained in step d) or possibly in step e) in the case where step e) is / are carried out, with at least one metal precursor from group VIB and / or at least one metal precursor from group VIII of the periodic table of elements, at least one organic additive chosen from dimethyl succinnate, gamma valerolactone, succinic acid and citric acid, alone or in mixture and possibly at least one dopant chosen from boron, phosphorus and silicon and preferably phosphorus, g) a step of drying the catalyst obtained at the end of step f) carried out at a temperature between 20 and 200°C preferably between 40 and 150°C and for a duration of between 1 hour and 3 weeks and preferably between 1 hour and 48 hours to obtain the dried catalyst. A process according to claim 1 wherein the alumina from step a) is in the form of extrudates. A process according to any one of claim 1 or 2 wherein said heat treatment step a) operates at a temperature between 520 and 850°C, preferably between 520 and 800°C and even more preferably between 530 and 750°C and for a duration between 1h and 12h, preferably between 1h30 and 100 and even more preferably between 2h and 8h. A process according to any one of claims 1 to 3 wherein the boron precursor is ammonium biborate. A method according to any one of claims 1 to 4 in which said calcination step d) is carried out in the presence of a dry air stream not containing water. A method according to any one of claims 1 to 5, wherein at least one metal from group VIII, at least one metal from group VIB, and at least one phosphorus dopant are deposited on said support in a first impregnation step h), said first impregnation step being followed by a drying step and then a second impregnation step h) of at least one organic additive selected from dimethyl succinnate, gamma valerolactone, succinic acid and citric acid, alone or in mixture, are used.

7. The process according to claim 6 wherein the organic additive is dimethyl succinnate.

8. A method according to any one of claims 1 to 5 wherein a single impregnation solution containing at least one metal from Group VIII, at least one metal from Group VIB, at least one phosphorus dopant and an organic additive selected from dimethyl succinnate, gamma valerolactone, succinic acid and citric acid, alone or in mixture, is used to impregnate said support in a single impregnation step.

9. A process according to any one of claims 1 to 8 wherein said catalyst obtained in step g) does not undergo a final calcination step.

10. A hydrotreating process for selected feedstocks from hydrocarbon cuts having a distillation range between 250°C and 600°C, preferably vacuum distillates, and renewable feedstocks selected from vegetable oils, algal oils, cooking oils, animal fats, fresh or used, alone or in mixtures, and feedstocks from the reprocessing of biomass and / or plastics and / or tires and / or household waste, alone or in mixtures, said process employing said catalyst comprising at least one metal from Group VIII and / or at least one metal from Group VIB of the periodic table of elements, at least one organic additive selected from dimethyl succinnate, gamma valerolactone, succinic acid and citric acid, alone or in mixtures and optionally at least one dopant selected from boron,phosphorus and silicon, and preferably phosphorus and a support comprising alumina containing boron, said catalyst being prepared according to the preparation process according to any one of claims 1 to 9.