Method for preparing a catalyst comprising a boron-doped alumina support, the boron being added during the shaping step

Abstract

The present invention relates to the preparation of a catalyst containing a specific organic additive, the catalyst comprising a support based on a mesoporous alumina containing boron, in which the boron source is introduced into the alumina during the step of shaping the catalyst support. As a result of its advantageous properties, the catalyst comprising a support based on an alumina containing boron can be used in all refining processes and also as an adsorbent, in particular for catalytic processes used to treat hydrocarbon fractions, such as the hydrotreatment of vacuum distillates.

Description

[0001] METHOD FOR PREPARING A CATALYST COMPRISING AN ALUMINUM SUPPORT

[0002] BORON-ENRICHED WITH ADDITION OF BORON DURING SHAPING

[0003] technical field

[0004] The present invention relates to the preparation of a catalyst comprising a support based on a mesoporous alumina containing boron into which the boron source is introduced at the step of shaping the bohemite gel, and into which specific organic additives are added on said catalyst.

[0005] The said catalyst, comprising a support based on an alumina containing boron, due to its interesting properties, can be used in all refining processes as well as as an adsorbent, in particular for catalytic processes dealing with hydrocarbon cuts such as vacuum hydrotreating of distillates.

[0006] Previous art

[0007] Patent CN112547069B describes a method for preparing a catalyst for the synthesis of methylisobutanol. The catalyst is copper-nickel based on a theta alumina support containing boric acid. Boron is introduced by impregnating the shaped theta alumina support with boric acid or directly during shaping by mixing the theta alumina with boric acid. The amount of boron present in the support is between 0.5 and 3%. No textural characteristics of the support or the resulting catalyst are given.

[0008] Patent JP5890729B describes a method for preparing a hydrodenitrogenation catalyst. The catalyst support is preferably a mixture of alumina and boron oxide with a boron oxide concentration between 4 and 8%. No information is provided on how to prepare the support. No textural characteristics of the support or the resulting catalyst are given.

[0009] Patent WO2016170188 describes a catalyst comprising a Group VIII metal, a Group VI B metal, at least one mercaptocarboxylic acid, and a support containing at least one dopant selected from boron, silicon, and phosphorus alone or in mixtures. In the case of a boron dopant, the amount of boron, expressed as boron oxide (B₂O₃), is between 0 and 13%, preferably between 2 and 8%, and preferably between 2 and 6% by weight relative to the mass of the catalyst. A method for preparing said hydrotreating catalyst is also described. The boron source can be introduced as a powder or solution by co-precipitation and / or mixing with an alumina or silica-alumina source to form an extrudable paste.The mixture is then shaped by extrusion, dried and calcined to form a support having a porous volume measured by mercury porosimetry of between 0.5 and 2 mL / g preferably between 0.75 and 1 mL / g and a BET surface of between 30 and 400 m. 2 / g. Metals, an organic additive such as mercaptocarboxylic acid, and possibly phosphorus can then be impregnated onto the formed support in one or more stages. In the examples, the support is prepared by mixing alumina hydrate with boric acid to form a paste, to which nitric acid is added as a peptizing agent before extrusion.

[0010] Patent application W02010121807 describes a catalyst comprising a Group VIII metal, a Group VI B metal, phosphorus, and a boron-containing support. The catalyst's activity is significantly enhanced by the use of relatively high amounts of boron and phosphorus. The phosphorus content is greater than 1 wt%, expressed as P₂O₅, and the boron content, expressed as boron oxide (B₂O₃), is between 1 and 13%, preferably between 2 and 8%, and more preferably between 2 and 6%, by weight relative to the catalyst mass. A method for preparing the hydrotreating catalyst is also described. Preferably, the boron-containing catalyst support is obtained by co-extrusion of the catalyst support precursor (such as bohemite or pseudo-bohemite) and a boron source.It has been discovered that co-extrusion is advantageous compared to boron impregnation on the support because it allows for the introduction of a significant amount of boron into the support. Preferably, the boron source is added at the beginning of the mixing process. The boron source is chosen from metabolic acid (HBO2), orthoboric acid (H3BO3), ammonium tetraborate tetrahydrate [(NH4)2B4O7*4H2O], sodium tetraborate, ammonium borate, and ammonium tetraborate. Boric oxide (B₂O₃), various mono-, di-, and trialkyl amine borates (e.g., triethanolamine borate), ammonium tetraphenylborate, or similar compounds are used. The shaped boron-containing support is then dried, calcined, and impregnated with a solution comprising the phosphorus source and metal precursors. The impregnation solution may also include organic additives.Patent J P07-155615 describes a hydrotreating catalyst comprising a metal from Group V1, a metal from Group VIII, and monosaccharide and / or disaccharide additives selected from glucose, fructose, maltose, lactose, and sucrose, and a boron-containing support in which the amount of boron, expressed as B2O3 oxide, is between 3 and 15% by weight relative to the mass of the support, the mean pore diameter of the support, measured by mercury porosimetry, is between 80 and 110 µm, and the pore volume, within ±10 µm of the mean diameter, represents more than 60% of the total volume of the support. The method for preparing said catalyst is also described. Boric acid, tetraboric acid, and ammonium borate are presented as sources of boron. For the preparation of the support, an alumina hydrate comprising 0.05% by weight of Na2O and 0.20% by weight of SC4 is used. 2+The mixture is combined with an aqueous boric acid solution to achieve a boron oxide content, expressed as B₂O₃, of 3 to 15% by weight. The mixture is then shaped to create a boron-containing support. A solution containing the metals, a mono- or disaccharide, and an organic acid such as citric or tartaric acid is then impregnated onto the boron-containing support. The resulting catalyst is then dried to prevent the decomposition of the mono- and disaccharides.

[0011] Patent application CN103372449A describes a method for preparing a boron-containing hydrotreating catalyst. The amount of boron, considered as B₂O₃, is between 2 and 35% by weight relative to the mass of the support. The boron-containing compound can be selected from boron oxide, boric acid, ammonium hydrogen borate, ammonium tetraborate, ammonium pentaborate, sodium borate, ammonium fluoroborate, boron trifluoride, and methyl borate. The boron is introduced by stir-extrusion with an alumina support or alumina precursor.

[0012] The applicant demonstrated that preparing a catalyst comprising an alumina-based support containing boron, with the boron source added during the shaping step of a bohemite gel, combined with the use of specific organic additives added to said catalyst, makes it possible to obtain a catalyst comprising a boron-doped alumina support exhibiting textural properties suitable for use in hydrotreating reactions of hydrocarbon feedstocks, such as the vacuum hydrotreating of distillates. In particular, the catalyst obtained by the process according to the invention provides improved performance in the vacuum hydrodeazotation of distillate feedstocks compared to that obtained with a catalyst comprising an alumina-based support not containing boron and not containing the organic additives as defined in the invention.

[0013] Summary and significance of the invention

[0014] The present invention relates to a process for preparing a catalyst comprising at least one metal from Group VI B 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 boron-containing alumina, said process comprising and preferably consisting of at least the following steps: a) at least one or more steps of precipitating 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 and aluminum chloride.aluminium nitrate, sulfuric acid, hydrochloric acid, and nitric acid, in which at least one of the basic or acid precursors comprises aluminium, the relative flow rate of the acid and basic precursors is chosen so as to obtain a pH of the reaction medium between 8.9 and 10.0 and the flow rate of the acid and basic precursor(s) containing aluminium is adjusted so as to obtain a degree of advancement of said first step between 15 and 100% and preferably between 17 and 100%, the degree of advancement being defined as the proportion of boehmite gel formed in Al2O3 equivalent during said first precipitation step relative to the total quantity of boehmite gel formed in Al2O3 equivalent at the end of the precipitation step(s) implemented, said precipitation step operating at a temperature between 20 and 80°C, and for a duration between 2 and 30 minutes,b) optionally one or more heat treatment steps of the suspension obtained at the end of step a) at a temperature between 70 and 100°C for a duration of between 30 minutes and 5 hours, c) a filtration step of the suspension obtained at the end of heat treatment step a) or optionally at the end of step b), followed by at least one washing step of the boehmite gel obtained, d) a drying step of the boehmite gel obtained at the end of step c) to obtain a powder, e) a shaping step of the powder obtained at the end of step d) by mixing it with at least one boron source to obtain the raw material, f) a drying step of the raw material obtained in shaping step e) carried out at a temperature between 20 and 200°C and for a duration of between 1 hour and 3 weeks to obtain a dried raw material,(g) a heat treatment step of the dried raw material obtained at the end of step (f) at a temperature between 500 and 1000°C, and for a duration of between 1 and 12 hours, with or without an airflow containing up to 60% by volume of water, to obtain an alumina support containing boron; (h) one or more impregnation steps of the alumina support containing boron obtained at the end of step (g) with at least one metal precursor from group VI B 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.(i) a drying step of the catalyst obtained at the end of step (g) 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 a dried catalyst.

[0015] The process according to the present invention allows the obtaining of a catalyst based on a support comprising an alumina including boron having textural properties adapted for its use in hydrocarbon conversion processes and in particular in vacuum hydrotreating processes of hydrocarbon feedstocks of distillate type.

[0016] 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 VI B, 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.

[0017] An advantage of the invention is that it provides a new process for preparing a catalyst based on an alumina support containing boron, in which the boron source is added during the shaping of the bohemian gel, combined with the use of specific organic additives. This process is inexpensive compared to conventional prior art alumina preparation processes, such as sol-gel preparation methods. In particular, the process according to the invention does not involve autoclaving, and each unit step of the process is economically attractive and has already been proven on an industrial scale.

[0018] Finally, another advantage of the preparation process according to the invention is that it allows the production of catalysts with unparalleled performance compared to catalysts containing or not containing boron described in the prior art.In particular, the activity in hydrotreating and in particular in hydrodeazotation of feeds selected from hydrocarbon cuts 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 household waste, alone or in mixtures, and in particular the hydrotreating of vacuum distillate cuts of a catalyst prepared according to the invention in which the boron precursor is introduced at the support shaping stage, is significantly superior to that of catalysts containing or not containing boron, prepared according to any prior art method known to the person skilled in the art.

[0019] In the following text, chemical element groups 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 in columns 8, 9, and 10 according to the new IUPAC classification, and group VI B to the metals in column 6.

[0020] In the following text, the expressions "between ... and ..." and "between ... and ..." are equivalent and mean that the limit values ​​of the interval are included within the described range of values. If this were not the case and the limit values ​​were not included within the described range, this clarification will be provided by the present invention.

[0021] In this description, the expression "greater than..." is understood as strictly greater, and symbolized by the sign ">", and the expression "less than" as strictly less, and symbolized by the sign "<".

[0022] 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.

[0023] In the context of the present invention, 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 context of the present invention, a preferred range of pressure values ​​can be combined with a more preferred range of temperature values.

[0024] Definitions and measurement methods.

[0025] The alumina support according to 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.

[0026] By "macropores" we mean pores with an opening greater than 50 nm.

[0027] By "mesopores" we mean pores whose opening is between 2 nm and 50 nm, inclusive.

[0028] By "micropores" we mean pores whose opening is strictly less than 2 nm.

[0029] 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".

[0030] We set at 0.2 MPa the value from which mercury fills all intergranular voids, and we consider that beyond this point mercury penetrates the pores of alumina.

[0031] To obtain better accuracy, the value of the total pore volume corresponds to the value of the total pore volume measured by mercury porosimetry measured on the sample less the value of the total pore volume measured by mercury porosimetry measured on the same sample for a pressure corresponding to 30 psi (approximately 0.2 MPa).

[0032] 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.

[0033] The volume of the micropores is measured by nitrogen porosimetry. Quantitative analysis of 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" by F. Rouquérol, J. Rouquérol and K. Sing, Academic Press, 1999.

[0034] The average diameter of 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.

[0035] The pore distribution measured by nitrogen adsorption was determined using the Barrett-Joyner-Halenda (BJH) model. The nitrogen adsorption-desorption isotherm according to the BJH model is described in the journal *The Journal of the 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 at P / Po = 0.99, the pressure at which it is assumed that nitrogen has filled all the pores.

[0036] 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).

[0037] X-ray diffraction on boehmite gels was performed using the classical powder method with a diffractometer.

[0038] 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 crystallite size. 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.

[0039] Description of the invention

[0040] According to the invention, said preparation process comprises at least one or more steps a) of precipitating 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 acidic precursors comprises aluminum, the relative flow rates of the acidic and basic precursors are chosen to obtain a pH of the reaction medium between 8.9 and 10.0, and the flow rate of the aluminum-containing acidic and basic precursor(s) is adjusted to obtain a degree of completion of the 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 Al2O3 equivalent during said step a) of precipitation or each of the precipitation steps implemented, relative to the total quantity of boehmite gel in Al2O3 equivalent formed at the end of the precipitation step(s) and more generally at the end of the boehmite gel preparation steps, said step a) operating at a temperature between 20 and 80°C, and for a duration between 2 and 40 minutes.

[0041] In general, the "progress rate" of the nth precipitation step means the percentage of boehmite gel formed in Al2O3 equivalent in said nth step, relative to the total quantity of boehmite gel formed at the end of all the precipitation steps and more generally at the end of the boehmite gel preparation steps.

[0042] The said nth precipitation step generally allows obtaining a boehmite gel suspension having an Al2O3 concentration between 20 and 100 g / l, preferably between 20 and 80 g / l, preferably between 20 and 60 g / l.

[0043] The simultaneous mixing in the aqueous reaction medium of at least one basic precursor and at least one acidic precursor requires either that at least the basic precursor or the acidic precursor includes aluminium, or that both the basic and acidic precursors include aluminium.

[0044] Basic precursors containing aluminum include sodium aluminate and potassium aluminate. Sodium aluminate is the preferred basic precursor.

[0045] The acid precursors containing aluminum are aluminum sulfate, aluminum chloride, and aluminum nitrate. The preferred acid precursor is aluminum sulfate.

[0046] Preferably, the basic and acid precursor(s) are added in said first precipitation step a) in aqueous solutions.

[0047] Preferably, the aqueous reaction medium is water.

[0048] Preferably, said step a) is carried out under agitation.

[0049] Preferably, said step a) is carried out in the absence of organic additives and preferably in the absence of gluconic acid.

[0050] Preferably, said step a) is carried out in the absence of a silica source.

[0051] Preferably, the reaction medium for step a) is water.

[0052] According to the invention, at least said basic aluminum precursor and at least said acidic aluminum precursor are added simultaneously to the reaction medium of step a) to maintain the pH constant in said step a).

[0053] The acidic and basic precursors, whether they contain aluminum or not, are mixed simultaneously, preferably in solution, in the aqueous reaction medium which may contain the soluble boron salt, in proportions such that the pH of the resulting suspension is between 8.9 and 10.0.

[0054] According to the invention, it is the relative flow rate of the acidic and basic precursors, whether they contain aluminum or not, that is chosen so as to obtain a pH of the reaction medium between 8.9 and 10.0.

[0055] Preferably, said step a) of precipitation is carried out at a pH between 8.9 and 9.8.

[0056] The acidic and basic precursors are also mixed in quantities sufficient to obtain a suspension containing the desired amount of boehmite gel, depending on the final boehmite gel concentration to be achieved. In particular, said step a), or each of the precipitation steps implemented, yields 15 to 100% by weight of boehmite gel in Al₂O₃ equivalent relative to the total amount of boehmite gel formed at the end of the precipitation step(s). According to the invention, the flow rate of the aluminum-containing acidic and basic precursor(s) is adjusted, depending on the duration of step a), so as to obtain a precipitation step a) completion rate of between 15 and 100%, and preferably between 17 and 100%.

[0057] If the degree of advancement obtained at the end of precipitation step a) is less than 100%, at least a second precipitation step is necessary to increase the amount of boehmite gel formed. When a second precipitation step is implemented, the degree of advancement is defined as the proportion of boehmite gel formed (in Al₂O₃ equivalents) during this second precipitation step relative to the total amount of boehmite gel formed (in Al₂O₃ equivalents) at the end of both precipitation steps of the preparation process according to the invention, and more generally, at the end of all the boehmite gel preparation steps.

[0058] Thus, depending on the target boehmite gel concentration at the end of the precipitation step(s), preferably between 20 and 100 g / l, the quantities of aluminium to be supplied by the acidic and / or basic precursors are calculated and the flow rate of the precursors is adjusted according to the concentration of said precursors in aluminium added, the quantity of water added to the reaction medium and the rate of advancement required for the precipitation step(s).

[0059] In cases where one or more co-precipitation steps are implemented after the first precipitation step, the relative flow rates of the acidic and basic precursors are chosen to obtain a reaction progress of the second step between 0 and 85%, and preferably between 0 and 83%, so that the cumulative reaction progress of the first and second precipitation steps is equal to 100%. The relative flow rates of the acidic and basic precursors are chosen to obtain a pH of the reaction medium for the said additional precipitation step(s) between 8.9 and 10.0, and preferably between 8.9 and 9.8.

[0060] The flow rates of the aluminum-containing acid and / or basic precursor(s) depend on the size of the reactor used and thus on the amount of water added to the reaction medium.

[0061] Preferably, said step a) and preferably each of the precipitation steps carried out is / are performed at a temperature between 20 and 80°C, preferably between 25 and 70°C, more preferably between 30 and 65°C. In the case where said preparation process according to the invention comprises two precipitation steps, precipitation step a) is advantageously carried out at a temperature lower than the temperature of the second precipitation step.

[0062] Preferably, said step a) and preferably each of the precipitation steps implemented is (are) carried out for a duration of between 2 and 40 minutes.

[0063] In the embodiment where several precipitation steps are implemented, preferably, between each precipitation step, a temperature increase can be carried out.

[0064] The said temperature increase can advantageously be carried out at a temperature between 20 and 90°C, preferably between 30 and 80°C, preferably between 30 and 70°C and most preferably between 40 and 65°C.

[0065] In this case, the said intermediate temperature rise is preferably implemented for a period of between 5 and 45 minutes and preferably between 7 and 35 minutes.

[0066] The said intermediate temperature rise is advantageously implemented according to all heating methods known to a person skilled in the art.

[0067] Step b) of heat treatment of the optional suspension

[0068] The said preparation process may optionally include one or more steps b) of heat treatment of the suspension obtained at the end of step a), the said heat treatment step(s) operating at a temperature between 70 and 100°C for a period of between 30 minutes and 5 hours.

[0069] One or more steps b) may advantageously be implemented in the case where only one precipitation step is implemented in the process according to the invention.

[0070] In the case where several precipitation steps a) are implemented, one or more heat treatment steps b) may advantageously be implemented after the last precipitation step a).

[0071] In the event that a heat treatment step of the suspension obtained at the end of step a) is implemented, at least one boron salt, preferably soluble, may optionally be added to the reaction medium during said heat treatment step b).

[0072] Preferably, said heat treatment step b) is a ripening step.

[0073] Preferably, the said heat treatment step(s) b) operate(s) at a temperature between 70 and 100°C and preferably between 70 and 90°C.

[0074] Preferably, the said heat treatment step(s) is / are carried out for a period of between 30 minutes and 5 hours.

[0075] This ripening stage is advantageously implemented using all heating methods known to those skilled in the art.

[0076] Step c) of filtration

[0077] According to the invention, the process according to the invention comprises a step c) of filtering the suspension obtained at the end of step a) or optionally at the end of step b) of heat treatment, followed by at least one step of washing the gel obtained. Said filtration step is carried out according to methods known to those skilled in the art.

[0078] The said filtration step is advantageously followed by at least one water washing step and preferably by one to three washing steps, with a quantity of water equal to the quantity of precipitate filtered.

[0079] According to the invention, the boehmite gel obtained at the end of step c) of filtration, is dried in a step d) of drying to obtain a powder.

[0080] The said 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, or by spraying.

[0081] In the case where drying step d) is carried out by spray drying, the cake obtained after the heat treatment step, possibly followed by a filtration step, is resuspended. This suspension is then sprayed as fine droplets into a vertical cylindrical chamber in contact with a stream of hot air to evaporate the water according to the principle well known to those skilled in the art. The resulting powder is carried by the heat flow to a cyclone or baghouse filter, which separates the air from the powder. Preferably, in the case where drying step d) is carried out by spray drying, the spray drying is performed according to the operating procedure described in the publication Asep Bayu Dani Nandiyanto, Kikuo Okuyama, Advanced Powder Technology, 22, 1-19, 2011.

[0082] Boehmite obtained in powder form is advantageously composed of crystallites whose size, obtained by Scherrer's formula in X-ray diffraction along the crystallographic directions (020) and (120) is respectively between 2 and 40 nm and between 2 and 50 nm.

[0083] The boehmite thus prepared makes it easier to shape the said gel according to all the methods known to the person skilled in the art and in particular by mixing extrusion, by granulation and by the technique known as "oil drop" according to Anglo-Saxon terminology.

[0084] Step e) of formatting

[0085] According to the invention, the powder obtained at the end of step d) of drying is shaped in a step e) by mixing with at least one source of boron to obtain a raw material.

[0086] Raw material is defined as material that has been shaped and has not undergone any heat treatment steps.

[0087] Preferably, said shaping step e) is carried out by extrusion mixing, pelletizing, the oil-drop coagulation method, rotary plate granulation or any other method well known to those skilled in the art.

[0088] Preferably, said shaping step e) is carried out by mixing extrusion.

[0089] According to the invention, at least one source of boron is added in the shaping step.

[0090] The said source of boron is chosen from boric acid (H3BO3), sodium tetraborate decahydrate (Na2B4O7*10H2O), sodium metaborate (NaBC>2), ammonium pentaborate tetrahydrate ((NH^BsOs F^O), ammonium tetraborate tetrahydrate (H8B4N2O7 H2O) or any other boron salt, alone or in mixture.

[0091] The boron source is preferably chosen from boric acid (H3BO3) and ammonium tetraborate tetrahydrate (H8B4N2O7 H2O), alone or in mixture. The quantity of boron source added in step e) is advantageously adjusted so that the final alumina obtained comprises a boron content of between 0.1 and 10% wt%, preferably between 0.1 and 9%, and even more preferably between 0.1 and 4%, relative to the total wt% of said alumina in Al2O3 equivalent.

[0092] In a preferred embodiment, said shaping step e) is carried out by mixing-extrusion, said step e) being carried out with a total acid content, expressed as a percentage by weight relative to the mass of dried powder introduced in step e) of between 0 and 10% and a neutralization content expressed as a percentage by weight of base relative to the amount of acid introduced in said step e) of between 0 and 200%.

[0093] Preferably, said step e) is carried out with a total acid content, expressed as a percentage relative to the mass of dried gel introduced in step e), of between 0.5 and 8%, and most preferably between 1 and 6%, and a neutralization content expressed as a percentage by weight of base relative to the amount of acid introduced in said step e) of between 0.5 and 150%, preferably between 1 and 130%, most preferably between 10 and 100%, most preferably between 1 and 80%, and most preferably between 1 and 60%.

[0094] Preferably, the acid used in step e) is chosen from nitric acid and carboxylic acids, preferably chosen from acetic acid, citric acid and butyric acid, and preferably nitric acid.

[0095] Preferably, the base used in step e) is chosen from among the inorganic bases selected from sodium hydroxide, potassium hydroxide, and ammonia, and the organic bases in solution selected from among the amines and quaternary ammonium compounds. Preferably, the organic bases in solution are chosen from among the alkylethanolamines and ethoxylated alkylamines. The organic bases are preferably used in aqueous solution.

[0096] Preferably, the said base is ammonia and preferably ammonia in aqueous solution (NH4OH+ H2O).

[0097] Preferably, the boron source can be added at any time during the shaping stage. It can advantageously be added before the mixing stage, and preferably it can be added in the mixer mixed with the bohemite powder obtained before mixing.

[0098] It can also be added during the mixing stage and preferably at the beginning of the mixing stage.

[0099] According to the invention, the raw material obtained at the end of step e) of shaping, is dried in a step f) of drying 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 raw material.

[0100] According to the invention, the dried raw material obtained at the end of step f) of drying then undergoes a step g) of heat treatment at a temperature between 500 and 1000°C, for a period of between 1 and 12 h, in the presence or not of an airflow containing up to 60% by volume of water to obtain the alumina support containing boron.

[0101] Preferably, said heat treatment step g) operates at a temperature between 520 and 850°C, preferably between 520 and 800°C and even more preferably between 530 and 750°C.

[0102] Preferably, said heat treatment step g) operates for a duration of between 1h and 12h, preferably between 1h30 and 10h and even more preferably between 2h and 8h.

[0103] Said heat treatment step g) allows the transition of boehmite to the final alumina, and allows adjustment of the final porous texture of the alumina prepared according to the invention and which contains Boron.

[0104] The boron content in the material and preferably in the alumina obtained at the end of step g) is preferably between 0.1 and 10% by weight, preferably between 0.1 and 9% and even more preferably between 0.1 and 4%, relative to the total weight of said alumina in Al2O3 equivalent.

[0105] Step (g) of the process according to the invention provides a mesoporous alumina containing boron and exhibiting 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. Preferably, said alumina comprises a boron content of between 0.1 and 10% by weight, more preferably between 0.1 and 9%, and even more preferably between 0.1 and 4%, relative to the total weight of said alumina in Al₂O₃ equivalent.

[0106] The mesoporous alumina containing boron obtained at the end of step g) of the process according to the invention is preferably free of micropores. The absence of micropores is measured and verified by nitrogen adsorption.

[0107] Preferably, said mesoporous alumina containing boron, prepared according to the process of the invention, is free of macropores. The absence of macropores is measured and verified by mercury porosimetry.

[0108] The mesoporous alumina containing boron obtained after step g) of heat treatment advantageously has a specific surface area BET of between 50 and 450 m 2 / g, preferably between 100 and 400 m 2 / g, preferably between 200 and 400 m 2 / g, and preferably between 220 and 380 m 2 / 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.

[0109] Preferably, the total porous volume of said boron-containing alumina measured by mercury porosimetry is between 0.6 and 0.9 ml / g.

[0110] Preferably, the percentage of volume contained in pores of size between 3.6 and 50 nm relative to the total pore volume of said boron-containing alumina measured by mercury porosimetry, is greater than 90% and preferably greater than 95%.

[0111] Preferably, the percentage of the mesoporous volume of pores with a diameter between 8 and 20 nm measured by mercury porosimetry is between 60 and 100%, preferably between 65 and 100%.

[0112] 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, and even more preferably between 9.5 and 12.0 nm. Preferably, the boron-containing alumina obtained at the end of step g) is non-mesostructured alumina.

[0113] Said mesoporous alumina containing boron advantageously has a sulfur content between 0.001% and 0.4% by weight and a sodium content between 0.001% and 0.04% by weight, the weight percentages being expressed in relation to the total mass of boehmite gel in its Al2O3 form.

[0114] Preferably, the boron-containing alumina obtained at the end of step g) is in the form of irregular and non-spherical beads, extrudates, pellets or agglomerates whose specific shape may result from a crushing step.

[0115] The form taken by the support comprising said boron-containing alumina is that of extrudates with a diameter between 0.8 and 3 mm, preferably between 1.2 and 2.6 mm. The geometry of the extrudates can be cylindrical, trilobular, quadrilobular or any other advantageous shape according to the desired application.

[0116] According to the invention, said boron-containing alumina obtained at the end of step g) is used as a catalyst support.

[0117] According to the invention, the process according to the invention comprises one or more step(s) h) of impregnation on said boron-containing alumina obtained at the end of step g) of at least one metal of group VIII and / or at least one metal of 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.

[0118] Preferably, the said step(s) h) 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.

[0119] 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, may 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.

[0120] In a first preferred embodiment, at least one Group VIII metal, at least one Group VI B metal, and at least one phosphorus dopant are deposited on the support in a first impregnation step. This first impregnation step is followed by a drying step and then a second impregnation step with at least one organic additive selected from dimethyl succinnate, gamma-valerolactone, succinic acid, and citric acid, alone or in mixtures. A final drying step is also advantageously carried out after the impregnation with the organic additive.

[0121] 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 dimethyl succinnate, gamma valerolactone, succinic acid and citric acid, alone or in mixture, is used to impregnate said support in a single impregnation step.

[0122] 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.

[0123] The content of group VIII metal in the catalyst is advantageously 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.

[0124] The content of Group VIB metal in the catalyst is advantageously 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 Group VIB metal oxide relative to the total weight of the catalyst. The molar ratio of Group VIII metal to Group VIB metal in the catalyst is advantageously 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.

[0125] The catalyst advantageously has a dopant content and preferably a phosphorus content of 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 P2Os relative to the total weight of fresh catalyst.

[0126] 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.

[0127] 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 h). Preferably, the organic additive is dimethyl succinnate.

[0128] The content of organic additive(s) containing oxygen and / or nitrogen and / or sulfur on the catalyst is advantageously 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.

[0129] The organic additive(s) introduced during step f) of the catalyst preparation process according to the invention are advantageously introduced in a quantity corresponding to:

[0130] - to a compound molar ratio added by metal(s) of group VIB present(s) in the regenerated catalyst of between 0.01 and 2.0 mol / mol, preferably between 0.01 and 1.5 mol / mol, preferably between 0.01 and 1.0 mol / mol, and most preferably between 0.02 and 0.8 mol / mol,

[0131] - and to a compound molar ratio added by group VIII metal(s) present in the regenerated catalyst of 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.

[0132] When several compounds are present, the different molar ratios are added together so that the sum of the added compounds corresponds to the values ​​given above. According to the invention, the catalyst obtained at the end of step h) is dried in a drying step i) carried out at a temperature between 20 and 200°C, preferably between 40 and 150°C, and for a duration between 1 hour and 3 weeks, and preferably between 1 hour and 48 hours, to obtain a dried catalyst.

[0133] Preferably, said catalyst does not undergo a 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.

[0134] Another object of the present invention is a hydrotreating process for hydrocarbon cuts using a catalyst containing an alumina comprising boron, said catalyst being prepared according to the preparation process according to the invention.

[0135] 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 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 a support comprising alumina containing boron, said catalyst being prepared according to the preparation process of the invention.

[0136] Before its use in a hydrocarbon fraction hydrotreating process, the catalyst is advantageously subjected to sulfidation to obtain the metals in their sulfided or partially sulfided forms as described below. This activation or sulfidation step is carried out using methods well known to those skilled in the art, and advantageously under a sulfur-reducing atmosphere in the presence of hydrogen and hydrogen sulfide. The catalyst is advantageously sulfided ex situ or in situ. Sulfurizing agents include 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 in order to sulfidize the catalyst.The sulfur-containing compounds are advantageously chosen from alkyl disulfides such as dimethyl disulfide (DMDS), alkyl sulfides such as dimethyl sulfide, thiols such as n-butyl mercaptan (or 1-butanethiol), and polysulfide compounds of the tertiononyl polysulfide type. The catalyst can also be sulfided with 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. Most preferably, the catalyst is sulfided in situ in the presence of a hydrocarbon feedstock supplemented with dimethyl disulfide.

[0137] Preferably, heavy hydrocarbon feedstocks are selected from those with a weighted average temperature (WAT) above 380°C. WAT is defined as the distillation temperatures of 5%, 50%, and 70% of the feed volume using the following formula: WAT = (T 5% + 2 x T 50% + 4 x T 70%) / 7. WAT is calculated from simulated distillation values. The WAT of the feed is above 380°C and preferably below 600°C, and even more preferably below 580°C.

[0138] 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.

[0139] The said hydrocarbon feedstock is advantageously chosen from LCO or HCO (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 or from conversion units such as catalytic cracking, coker or visbreaking, feedstocks from aromatic extraction units, lubricating oil bases or from solvent dewaxing of lubricating oil bases, distillates from 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.

[0140] Preferably, said hydrocarbon charge is a vacuum distillate.

[0141] 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, it can have any distribution among the different chemical families, including paraffins, olefins, naphthenes, and aromatics. Advantageously, this hydrocarbon feed 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, particularly additive catalysts.

[0142] The nitrogen content is advantageously 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 is advantageously 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 by weight.

[0143] The sulfur content in the feed is advantageously between 0.01 and 5% by weight, preferably between 0.2 and 4% by weight and even more preferably between 0.5 and 3% by weight.

[0144] The hydrocarbon feedstock may advantageously contain metals, in particular nickel and vanadium. The cumulative nickel and vanadium content of the hydrocarbon feedstock, treated according to the hydrocracking process of the invention, is preferably less than 1 ppm by weight.

[0145] The asphaltene content of said hydrocarbon feedstock is advantageously less than 3000 ppm, preferably less than 1000 ppm, even more preferably less than 200 ppm.

[0146] The treated feed advantageously 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.

[0147] According to the invention, the feedstock treated in the hydrotreating process is selected from renewable feedstocks chosen from vegetable oils, algal oils, cooking oils, animal fats, fresh or used, alone or in mixtures, and feedstocks derived from the reprocessing of biomass and / or plastics and / or tires and / or household waste, alone or in mixtures. The feedstock treated according to the hydrotreating process of the invention may also be a mixture of the aforementioned feedstocks.

[0148] The catalyst prepared according to the invention can then advantageously be used in one, two, or more reactors. It is advantageously used for implementation in a fixed bed.

[0149] The operating conditions used for the operation, preferably in a fixed bed, of the catalyst prepared according to the invention correspond to those advantageously 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 feed flow rate to the volume of the catalyst per hour) is advantageously between 0.1 and 20 h -1 and preferably between 0.2 and 5 hours 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 l / l and 2000 l / l.

[0150] The invention is illustrated by the following examples, which are in no way intended to be limiting.

[0151] Examples:

[0152] Example 1: according to the invention, synthesis of boehmite gel:

[0153] The synthesis of boehmite gel is carried out according to a preparation process conforming to the invention in a 5 L reactor in two precipitation stages. Agitation is maintained at 350 rpm throughout the synthesis.

[0154] The final concentration of boehmite gel, considered in the target form of Al2O3, is 43 g / l. The quantity of water added to the reactor before the first co-precipitation is 2700 mL water.

[0155] A first co-precipitation step in water, involving the simultaneous addition of aluminum sulfate Al₂(SO₄)₃ and sodium aluminate NaAlOO₄, is carried out at 40°C and pH 9.4 for 8 minutes. The concentrations of the aluminum precursors used are as follows: Al₂(SC₄)₃ at 102 g / L in Al₂C₄₃ and NaAlOO₄ at 155 g / L in Al₂O₃.

[0156] An aluminium sulfate solution Al2(SO4)3 is added continuously to the reactor containing water for 8 minutes at a rate of 12.5 ml / min simultaneously with a sodium aluminate solution NaAlOO at a rate of 15.6 ml / min in order to adjust the pH to a value of 9.4. The temperature of the reaction medium is maintained at 40°C.

[0157] A suspension containing a precipitate of boehmite gel is obtained.

[0158] The progress rate of the first stage of precipitation is 17.5%.

[0159] The resulting suspension is then subjected to a temperature increase from 40 to 60°C over 30 minutes.

[0160] A second co-precipitation step of the resulting suspension is then carried out by the simultaneous addition of aluminum sulfate Al₂(SC₄)₃ at a concentration of 102 g / L Al₂O₃ and sodium aluminate NaAlOO₄ at a concentration of 155 g / L Al₂O₃. An aluminum sulfate solution Ah(SO₄)₃ is therefore continuously added to the heated suspension obtained after the first precipitation step for 30 minutes at a rate of 10.3 mL / min, simultaneously with a sodium aluminate solution NaAlOO₄ at a rate of 13.5 mL / min, in order to adjust the pH to a value of 9.7. The temperature of the reaction medium in the second step is maintained at 60°C.

[0161] These flow rates of acidic and basic precursors containing aluminum allow for an advancement of 82.5% at the end of the second precipitation stage, with the cumulative advancement of the first and second precipitation stages being 100%. A suspension containing a boehmite gel precipitate is obtained.

[0162] The resulting suspension is then filtered by water displacement over a sintered Buchner type tool and the resulting alumina gel is washed 3 times with 5 L of distilled water.

[0163] The characteristics of the boehmite gel thus obtained are summarized in Table 1.

[0164] Table 1: Characteristics of the boehmite gel obtained according to example 1.

[0165] Table 1

[0166] The boehmite gel obtained according to example 1 was dried in a ventilated study at 120°C for 16 hours.

[0167] Example 2: According to the invention, preparation of an alumina containing boron (H8B4N2O7*4H2O, 0.5% B). The preparation of an alumina is carried out according to a preparation process according to the invention with the addition of a boron source at the shaping stage before the mixing stage.

[0168] 26 g of boehmite gel with a loss on ignition (LOI) of 24.4%, obtained in Example 1, is introduced simultaneously with 2.2 g of ammonium tetraborate tetrahydrate (H8B4N2O7 H2O) into an 80 mL Brabender cam-arm mixer. Acidified water with nitric acid, at a total acid content of 4% (expressed by weight relative to the mass of dried powder, considered as Al2O3), is added over 5 minutes during mixing at 20 rpm. Acid mixing is continued for 15 minutes. A neutralization step is then carried out by adding an ammonia solution to the mixer at a neutralization content of 40% (expressed by weight of ammonia relative to the amount of nitric acid introduced for the acidification step). The mixing continues for 3 minutes.

[0169] The resulting paste is then extruded through a 2 mm trilobed die. The extrudates are dried at 100°C for 16 hours and then calcined for 4 hours at 540°C under a stream of air containing no water. The alumina obtained exhibits the characteristic peaks of gamma alumina in X-ray diffraction. The textural characteristics of the boron-containing gamma alumina formed are reported in Table 2:

[0170] Table 2: Characteristics of boron-containing alumina A obtained according to example 2. Table 2

[0171] Example 3: according to the invention, preparation of an alumina containing boron (H8B4N2O7 H2O, 0.5% B).

[0172] The preparation of alumina is carried out according to a process conforming to the invention, with the addition of boron salt at the shaping stage before the mixing stage. 26 g of boehmite gel having a loss on ignition (LOI) of 24.4%, obtained in Example 1, is introduced simultaneously with 2.2 g of ammonium tetraborate tetrahydrate (H8B4N2O7 H2O) into an 80 m³ Brabender cam-arm mixer. Acidified water with nitric acid at a total acid content of 4%, expressed by weight relative to the mass of dried powder considered in the form Al2O3 introduced into the mixer, is added over 5 minutes, during mixing at 20 rpm. Acid mixing is continued for 15 minutes. A neutralization step is then carried out by adding an ammonia solution to the mixer, at a neutralization rate of 40%, expressed as weight of ammonia relative to the amount of nitric acid introduced into the mixer for the acidification step.The mixing continues for 3 minutes.

[0173] The resulting paste is then extruded through a 2 mm trilobed die. The extrudates are dried at 100°C for 16 hours and then calcined for 4 hours at 540°C under a stream of air containing 20% ​​water by volume. The alumina obtained exhibits the characteristic peaks of gamma alumina in X-ray diffraction. The textural characteristics of the boron-containing gamma alumina formed are reported in Table 3:

[0174] Table 3: Characteristics of boron-containing alumina B obtained according to example 3.

[0175] Table 3

[0176] Example 4: according to the invention, preparation of an alumina containing boron (H8B4N2O7 H2O, 1% B).

[0177] The preparation of alumina is carried out according to a preparation process according to the invention with the addition of a boron source at the shaping stage, before the mixing stage.

[0178] 26 g of boehmite gel with a loss on ignition (LOI) of 24.4%, obtained in Example 1, is introduced simultaneously with 4.4 g of ammonium tetraborate tetrahydrate (H8B4N2O7 H2O) into an 80 mL Brabender cam-arm mixer. Acidified water with nitric acid, at a total acid content of 4% (expressed by weight relative to the mass of dried powder, considered as Al2O3), is added over 5 minutes during mixing at 20 rpm. Acid mixing is continued for 15 minutes. A neutralization step is then carried out by adding an ammonia solution to the mixer at a neutralization content of 40% (expressed by weight of ammonia relative to the amount of nitric acid introduced for the acidification step). The mixing continues for 3 minutes.

[0179] The resulting paste is then extruded through a 2 mm trilobed die. The extrudates are dried at 100°C for 16 hours and then calcined for 4 hours at 540°C under a stream of water-free air. The alumina produced exhibits the characteristic peaks of gamma alumina in X-ray diffraction. The textural characteristics of the boron-containing gamma alumina formed are shown in Table 4.

[0180] Table 4: Characteristics of boron-containing alumina C obtained according to example 4. Table 4

[0181] Example 5: according to the invention, preparation of an alumina containing boron (H3BO3, 0.5% B).

[0182] The preparation of alumina is carried out according to a preparation process according to the invention with the addition of a boron source at the shaping stage during the mixing stage.

[0183] 26 g of boehmite gel with a loss on ignition (LOI) of 24.4%, obtained in Example 1, is introduced into an 80 mL Brabender cam-arm mixer. Acidified water with nitric acid at a total acid concentration of 4%, expressed by weight relative to the mass of dried powder (Al₂O₃) introduced into the mixer, containing 0.56 g of boric acid (H₃BO₃), is added over 5 minutes, during mixing at 20 rpm. Acid mixing is continued for 15 minutes. A neutralization step is then carried out by adding an ammonia solution to the mixer at a neutralization concentration of 40%, expressed by weight of ammonia relative to the amount of nitric acid introduced into the mixer for the acidification step. Mixing is continued for 3 minutes.

[0184] The resulting paste is then extruded through a 2 mm trilobed die. The extrudates are dried at 100°C for 16 hours and then calcined for 4 hours at 540°C under a stream of air containing 20% ​​water by volume. The alumina obtained exhibits the characteristic peaks of gamma alumina in X-ray diffraction. The textural characteristics of the boron-containing gamma alumina formed are reported in Table 5.

[0185] Table 5: Characteristics of boron-containing alumina D obtained according to example 5.

[0186] Table 5

[0187] Example 6: according to the invention, preparation of an alumina containing boron (H3BO3, 1% B).

[0188] The preparation of alumina is carried out according to a preparation process according to the invention with the addition of a boron source at the shaping stage during the mixing stage.

[0189] 26 g of boehmite gel with a loss on ignition (LOI) of 24.4%, obtained in Example 1, is introduced into an 80 mL Brabender cam-arm mixer. Acidified water with nitric acid at a total acid concentration of 4%, expressed by weight relative to the mass of dried powder (Al₂O₃) introduced into the mixer, containing 1.12 g of boric acid (H₃BO₃), is added over 5 minutes, during mixing at 20 rpm. Acid mixing is continued for 15 minutes. A neutralization step is then carried out by adding an ammonia solution to the mixer at a neutralization concentration of 40%, expressed by weight of ammonia relative to the amount of nitric acid introduced into the mixer for the acidification step. Mixing is continued for 3 minutes.

[0190] The resulting paste is then extruded through a 2 mm trilobed die. The extrudates are dried at 100°C for 16 hours and then calcined for 4 hours at 540°C under a stream of water-free air. The alumina produced exhibits the characteristic peaks of gamma alumina in X-ray diffraction. The textural characteristics of the boron-containing gamma alumina formed are reported in Table 6.

[0191] Table 6: Characteristics of boron-containing alumina E obtained according to example 6.

[0192] Table 6

[0193] Example 7: according to the invention, preparation of an alumina containing boron (H3BO3, 2% B).

[0194] The preparation of alumina is carried out according to a preparation process according to the invention with the addition of boron salt at the shaping stage during the mixing stage.

[0195] 26 g of boehmite gel with a loss on ignition (LOI) of 24.4%, obtained in Example 1, is introduced into an 80 mL Brabender cam-arm mixer. Acidified water with nitric acid at a total acid concentration of 4%, expressed by weight relative to the mass of dried powder (Al₂O₃) introduced into the mixer, containing 2.24 g of boric acid (H₃BO₃), is added over 5 minutes, during mixing at 20 rpm. Acid mixing is continued for 15 minutes. A neutralization step is then carried out by adding an ammonia solution to the mixer at a neutralization concentration of 40%, expressed by weight of ammonia relative to the amount of nitric acid introduced into the mixer for the acidification step. Mixing is continued for 3 minutes. The resulting paste is then extruded through a 2 mm trilobed die.The extrudates obtained are dried at 100°C for 16 hours and then calcined for 4 hours at 540°C under a flow of air containing no water. The alumina obtained exhibits the characteristic peaks of gamma alumina in X-ray diffraction. The textural characteristics of the gamma alumina formed containing boron are reported in Table 7.

[0196] Table 7: Characteristics of boron-containing alumina F obtained according to example 7.

[0197] Table 7

[0198] Example 8: Catalysts according to the invention prepared from supports A to F

[0199] The supports A to F prepared according to the invention, containing boron, were dry-impregnated with an aqueous solution of nickel and molybdenum, targeting molybdenum and nickel contents of 28 wt% and 6.55 wt% respectively, expressed in their oxide form, corresponding to a theoretical molar ratio of 0.45. After a 6-hour curing period in a closed system, the extrudates were dried at 120°C for 1 hour before being dry-impregnated again with a solution containing an organic additive, namely dimethyl succinate. A final drying of the extrudates was then applied for one hour in air at 120°C.

[0200] Catalysts 1 to 6, respectively obtained, were then evaluated by hydrodeazotation of a vacuum distillate with a melting point (TM P) of 474°C (T5% = 389°C, T50% = 468°C, T70% = 498°C). The feed characteristics are as follows: sulfur 2.6 wt%, nitrogen 1350 ppm, basic nitrogen 392 ppm, resins 9.1 wt%.

[0201] The test was conducted in a pilot-scale, fixed-bed, flow-through isothermal reactor, with fluids circulating from bottom to top. After in-situ sulfidation at 350 °C in the pressurized unit using the vacuum distillate from the test to which 2 wt% dimethyl disulfide was 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 l / h and a temperature of 370°C.

[0202] Table 8 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.

[0203] The reference case of a non-conforming catalyst not containing boron is prepared from the bohemite gel of Example 1 which is shaped and calcined under the conditions described in Example 2, with the difference that no boron source is added at the shaping step.

[0204] Example 9: Catalyst 7 not in accordance with the invention

[0205] The catalyst 7 not according to the invention is prepared from the support C containing B by dry impregnation with an aqueous solution based on nickel and molybdenum, aiming for molybdenum and nickel contents of 28% wt and 6.55% wt respectively, expressed in their oxide form, which corresponds to a theoretical molar ratio of 0.45. After a maturation step of 6h in a closed vessel, the extrudates were dried at 120°C for 1 hour before being again dry impregnated with a solution containing an organic additive not according to the invention, triethylene glycol (TEG).

[0206] Table 8 Furthermore, the examples provided highlight the interest of the textural distributions of the catalysts according to the invention, combined with the presence of Boron and a specific organic additive according to the invention, because the hydrodeazotation performance of distillate feedstocks under vacuum, of the catalysts according to the invention prepared from supports A to F, is significantly higher than the performance of the reference catalyst comprising a non-conforming support not containing Boron or the desired textural characteristics.

[0207] Similarly, the use of the specific organic additive according to the invention allows for improved catalytic performance compared to the catalyst comprising a non-compliant additive (TEG).

Claims

DEMANDS 1. A process for preparing a catalyst comprising at least one metal of Group VI B and at least one metal of 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 boron-containing alumina, said process comprising and preferably consisting of at least the following steps: a) at least one or more steps of precipitating 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, in which at least one of the basic or acid precursors comprises aluminium, the relative flow rate of the acid and basic precursors is chosen so as to obtain a pH of the reaction medium between 8.9 and 10.0 and the flow rate of the acid and basic precursor(s) containing aluminium is adjusted so as to obtain a degree of advancement of said first step between 15 and 100% and preferably between 17 and 100%, the degree of advancement being defined as the proportion of boehmite gel formed in Al2O3 equivalent during said first precipitation step relative to the total quantity of boehmite gel formed in Al2O3 equivalent at the end of the precipitation step(s) implemented, said precipitation step operating at a temperature between 20 and 80°C, and for a duration between 2 and 30 minutes,b) optionally one or more heat treatment steps of the suspension obtained at the end of step a) at a temperature between 70 and 100°C for a duration between 30 minutes and 5 hours, c) a filtration step of the suspension obtained at the end of heat treatment step a) or optionally at the end of step b), followed by at least one washing step of the boehmite gel obtained, d) a drying step of the boehmite gel obtained at the end of step c) to obtain a powder, e) a shaping step of the powder obtained at the end of step d) by mixing it with at least one boron source to obtain the raw material, f) a drying step of the raw material obtained in shaping step e) carried out at a temperature between 20 and 200°C and for a duration of between 1 hour and 3 weeks to obtain a dried raw material, g) a heat treatment step of the dried raw material obtained at the end of step f) at a temperature between 500 and 1000°C, and for a duration of between 1 and 12 hours, with or without an airflow containing up to 60% by volume water, to obtain the alumina support containing boron, h) one or more impregnation steps of the alumina support containing boron obtained at the end of step g) with at least one metal precursor from group VI B 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 acid citricalone or in mixture and possibly at least one dopant selected from boron, phosphorus and silicon, and preferably phosphorus, i) a drying step of the catalyst obtained at the end of step g) 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 a dried catalyst.

2. A method according to claim 1 in which said shaping step e) is carried out by mixing extrusion.

3. A process according to any one of claim 1 or 2 wherein said boron source is selected from boric acid (H3BO3), sodium tetraborate decahydrate (Na2B4O7*10H2O), sodium metaborate (NaBO2), ammonium pentaborate tetrahydrate ((NH4)B5O8*4H2O), ammonium tetraborate tetrahydrate (H8B4N2O7*4H2O), alone or in mixture.

4. A process according to claim 3 wherein the boron source is selected from boric acid (H3BO3) and ammonium tetraborate tetrahydrate (H8B4N2O7*4H2O), alone or in mixture.

5. A process according to any one of claims 2 to 4, wherein said step e) is carried out with a total acid content, expressed as a percentage by weight relative to the mass of dried powder introduced in step e), of between 0 and 10% and a neutralization content expressed in percentage weight of base relative to the quantity of acid introduced in said step e) between 0 and 200%.

6. A method according to any one of claims 2 to 5 wherein the boron source is added before the mixing step, and preferably in the mixer mixed with the bohemite powder obtained before mixing.

7. A method according to any one of claims 2 to 5 wherein the boron source is added during the mixing step and preferably at the beginning of the mixing step.

8. A process according to any one of claims 1 to 7 wherein at least one metal from group VIII, at least one metal from group VI B, 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 is carried out.

9. A process according to any one of claims 1 to 7 wherein the organic additive is dimethyl succinnate.

10. A hydrotreating process for feedstocks selected 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.

Images