Method for preparing an extruded catalyst based on catalyst fines without final calcination

Abstract

A method for preparing a catalyst from catalyst fines comprising a group VIB metal, a group VIII metal, and an oxide support, said fines having a D90 size of less than or equal to 500 micrometers, the method comprising the following steps: a) mixing said fines and an extrusion aid, and optionally an inorganic oxide binder; b) kneading the mixture obtained in step a) by adding an aqueous solution containing a carboxylic acid; c) optionally adding a neutralizing agent chosen from an inorganic base and an organic base to said mixture obtained in step b); d) shaping the mixture obtained in step b) or c) by extrusion in order to obtain a solid; e) drying the solid obtained in step d) at a temperature below 200°C, without subsequently calcining it.

Description

[0001] PROCESS FOR PREPARING AN EXTRUDED CATALYST BASED ON CATALYST FINES WITHOUT FINAL CALCINATION

[0002] Scope of the invention

[0003] The present invention relates to a process for preparing a catalyst from catalyst fines comprising at least one metal from group VIB and / or at least one metal from group VI II B, and an oxide support. These catalysts are particularly intended for use in hydrocarbon hydrotreating and / or hydrocracking units.

[0004] Previous art

[0005] Usually, a hydrotreating catalyst for hydrocarbon cuts aims to eliminate the sulfur or nitrogen compounds contained in them in order to bring, for example, a petroleum product to the required specifications (sulfur content, aromatic content, etc.) for a given application (motor fuel, gasoline or diesel, domestic fuel oil, jet fuel).

[0006] Conventional hydrotreating and / or hydrocracking catalysts typically comprise an oxide support and an active phase based on group VIB and VIII metals in their oxide forms, along with phosphorus. The preparation of these catalysts generally involves impregnating the support with the metals and phosphorus, followed by drying and calcination to obtain the active phase in its oxide forms. Before use in a hydrotreating and / or hydrocracking reaction, these catalysts are usually subjected to sulfidation to form the active species.

[0007] The addition of an organic compound to hydrotreating catalysts to improve their activity has been recommended by those skilled in the art, particularly for catalysts prepared by impregnation followed by drying without subsequent calcination. These catalysts are often called "additized dried catalysts." They are known to improve the dispersion of metals on the support surface and / or to play a beneficial role during catalyst sulfidation. Numerous documents describe the use of various ranges of organic compounds as additives, such as nitrogen-containing and / or oxygen-containing organic compounds. Several patents, for example, claim the use of carboxylic acids (EP1402948, EP0482817).In particular, in document EP0482817, citric acid, but also tartaric, butyric, hydroxyhexanoic, malic, gluconic, glyceric, glycolic, and hydroxybutyric acids were described.

[0008] During operation in hydrotreating and / or hydrocracking processes, the catalyst becomes deactivated due to the accumulation of coke and / or sulfur compounds or other heteroelements on its surface. After a certain period, its replacement is therefore necessary. One way to dispose of spent catalysts is through landfilling, but this is becoming increasingly difficult due to environmental constraints.

[0009] To combat these drawbacks, regenerating hydrotreating catalysts from middle distillates or spent residues is an economically and environmentally attractive process because it allows these catalysts to be reused in industrial units rather than being sent to landfill or recycled (metal recovery). However, regenerated catalysts are generally less active than the original catalysts.

[0010] To compensate for the reduced hydrodesulfurizing activity of the regenerated catalyst, an additional treatment known as "rejuvenation" can be applied. The rejuvenation process involves re-impregnating the regenerated catalyst with a solution containing metallic precursors and / or organic or inorganic additives.

[0011] During the various stages of fresh catalyst preparation, regeneration, and rejuvenation processes, catalyst fines and / or substandard catalysts (insufficient metal content, low mechanical strength, or catalyst dimensions smaller than required) are generally produced. Recycling these catalyst fines and / or substandard catalysts to manufacture new catalysts would be advantageous.

[0012] The preparation of catalyst from catalyst fines is known.

[0013] US6127299 and US6030915 describe a process for preparing a catalyst suitable for hydrotreating heavy hydrocarbon feedstocks, comprising regenerating a spent catalyst, grinding to obtain fines, mixing the fines with a binder, and shaping by extrusion in the presence of an inorganic acid, followed by drying and calcination. The fines incorporation rate is between 5 and 95 wt%.

[0014] US2012 / 0205290 relates to a hydrotreating catalyst comprising a support formed from a mixture of inorganic oxide powder and catalyst fines, said catalyst also containing a metallic component, a chelating agent, and a polar additive, which are subsequently impregnated. The fines incorporation rate is a maximum of 50% by weight. The support is prepared by mixing in the presence of an inorganic acid, followed by drying and calcination.

[0015] Document CN112547080 describes a process for preparing a catalyst suitable for hydrotreating a diesel feedstock, comprising grinding to obtain fines, mixing the fines with a binder, and shaping by extrusion in the presence of an inorganic or organic acid, followed by drying and calcination at temperatures between 400 and 1000°C. The fines incorporation rate is between 10 and 50% by weight.

[0016] As indicated in the documents summarized above, it is desirable to have a catalyst preparation process that uses catalyst fines. However, it should be noted that the use of catalyst fines in the preparation and as components of certain catalyst compositions may result in a final catalyst with some reduced performance characteristics compared to new catalysts prepared without the use of fines.

[0017] The present invention aims to improve the processes of preparing a catalyst from catalyst fines to provide a final catalyst that can incorporate a high percentage of fines into the catalyst.

[0018] Objects of the invention

[0019] The invention proposes a process for preparing a catalyst from catalyst fines comprising at least one metal from group VIB and / or at least one metal from group VIII, and an oxide support, said fines having a D90 size less than or equal to 500 micrometers, the process comprising at least the following steps: a) mixing said fines and an extrusion aid, and optionally an inorganic oxide binder, b) kneading the mixture obtained in step a) by adding an aqueous solution containing a carboxylic acid, c) optionally adding to said mixture obtained in step b) a neutralizing agent selected from an inorganic base and an organic base, d) shaping the mixture obtained in step b) or c) by extrusion to obtain a solid, e) drying the solid obtained in step d) at a temperature below 200°C, without subsequent calcination.The preparation process according to the invention makes it possible to obtain a catalyst that is more active than comparable catalysts prepared with a final calcination step while ensuring good mechanical resistance.

[0020] Similarly, the preparation process according to the invention allows for a high incorporation rate of fines in the catalyst. Indeed, since the active phase containing the metals is supplied by the fines in the final catalyst, it is clearly advantageous to incorporate a high incorporation rate of fines in the catalyst to obtain high activity and / or avoid the need to reintroduce metals by impregnation later. The preparation process according to the invention makes it possible, in particular, to obtain a catalyst with an incorporation rate exceeding 50% by weight of fines, the remainder being an inorganic oxide binder. It is even possible to obtain a catalyst with an incorporation rate of 100% by weight of fines, that is to say, a catalyst that does not contain any added inorganic oxide binder.

[0021] According to one variant, the D90 size of the fines is less than 300 micrometers.

[0022] According to one variant, the fines content is between 10% and 100% relative to the weight of the catalyst prepared by the process according to the invention.

[0023] According to one variant, the fines have a group VI B metal content of between 5 and 40% by weight of group VI B metal oxide and a group VIII metal content of between 1 and 50% by weight of group VIII metal oxide relative to the weight of the fines.

[0024] According to one variant, the fine oxide support is chosen from alumina, silica, silica-alumina, titanium or magnesium oxide used alone or in mixture with alumina or silica-alumina.

[0025] According to one variant, the said inorganic oxide binder is present and is chosen from the group formed by the following oxides or their hydrated forms: alumina, silica, silica-alumina, clays, titanium oxide, boron oxide and zirconia, taken alone or in mixture.

[0026] According to one variant, the content of extrusion aid agent is between 0.1 and 10% weight relative to the weight of dry fines and optional dry inorganic oxide binder introduced in step a).

[0027] In one variant, the extrusion aid is selected from methylcellulose, cellulose, carboxymethylcellulose, and carboxyethylcellulose. In another variant, the carboxylic acid is selected from formic acid, acetic acid, oxalic acid, citric acid, and γ-ketovaleric acid, alone or in mixtures.

[0028] According to one variant, the amount of carboxylic acid added is defined by a total acid rate, expressed as a percentage relative to the weight of the dry fines and the optional dry inorganic oxide binder introduced in step a) and is between 0.1 and 20 wt%.

[0029] According to one variant, the aqueous solution containing a carboxylic acid also contains at least one organic compound exhibiting complexing properties.

[0030] According to one variant, when step c) is carried out, said mixture obtained in step b) is added a neutralizing agent chosen from an inorganic base and an organic base, said inorganic base being chosen from sodium hydroxide, potassium hydroxide, and ammonia, alone or in mixture and said organic base being chosen from amines and quaternary ammonium compounds, alone or in mixture.

[0031] According to one variant, the quantity of neutralizing agent is defined by a neutralization rate expressed as a base molar percentage relative to the number of moles of protons present in step b) and is between 1 and 100%.

[0032] According to one variant, the process includes a step f) in which at least one metal from group VI B and / or at least one metal from group VIII, and optionally phosphorus and / or at least one organic compound comprising oxygen and / or nitrogen and / or sulfur, is contacted with said catalyst obtained after step e) of drying, the contacting being followed by a drying step at a temperature below 200°C, without subsequent calcination.

[0033] According to one variant, said catalyst obtained after the drying step e) or after the step f) is subjected to a sulfidation step, without an intermediate calcination step.

[0034] Definitions

[0035] 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.

[0036] 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 preferred range of temperature values.

[0037] 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.

[0038] In this description, the term "include" is synonymous with (means the same as) "include" and "contain," and is inclusive or open-ended, not excluding other elements not mentioned. It is understood that the term "include" includes the exclusive and closed term "consist."

[0039] According to the present invention, pressures are absolute pressures, also noted as abs., and are given in absolute MPa (or abs. MPa), unless otherwise indicated.

[0040] 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 (or VI 11 B) according to the CAS classification corresponds to the metals in columns 8, 9, and 10 according to the new IIIPAC classification, and group VI B to the metals in column 6.

[0041] Elemental analyses, typically by inductively coupled plasma (ICP) spectrometry, or by X-ray fluorescence spectrometry, more commonly called X-ray fluorescence (FX), allow the content of the different elements of the fines pretreated at 550°C under air to be quantified.

[0042] The catalyst obtained by the process according to the 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.

[0043] By "macropores" we mean pores with an opening greater than 50 nm.

[0044] By "mesopores" we mean pores whose opening is between 2 nm and 50 nm, inclusive.

[0045] By "micropores" we mean pores with an opening of less than 2 nm.

[0046] 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).

[0047] The volume of macropores and mesopores was measured by mercury intrusion porosimetry 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.

[0048] 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 the sample.

[0049] The macroporous volume of the catalyst 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.

[0050] The mesoporous volume of the catalyst 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 nm and 50 nm.

[0051] 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.

[0052] In the following description of the invention, the total pore volume of the catalyst is understood to be the sum of the mesoporous, macroporous (measured by intrusion in a mercury porosimeter) and microporous (measured by nitrogen porosimetry) volumes.

[0053] The mechanical strength of the material according to the invention is determined by the grain-by-grain (GBG) crush test. This is a standardized test (ASTM D4179-01) which consists of subjecting a material in the form of a millimeter-sized object, such as a ball, pellet, or extrudate, to a compressive force that causes it to break. The analysis is repeated on a number of individual solids, typically between 10 and 200. The average of the measured lateral breaking forces constitutes the average GBG, which is expressed in units of force (N) for granules and in units of force per unit length (daN / mm or decaNewton per millimeter of extrudate length) for extrudates.

[0054] The contents of the different components used in the process according to the invention (fines, binder, carboxylic acid, neutralizing agent, etc.) are expressed on the basis of the weight of the dry fines and possibly on the basis of the weight of the dry inorganic oxide binder when present.

[0055] The loss on ignition (or LOI) of a solid is the relative mass loss (expressed as a percentage) of a solid when it has been heated to 1000°C for 3 hours in a muffle furnace. LOI thus expresses the water and organic compound content. When the fines contain molybdenum, the LOI is measured at 550°C for 3 hours in a muffle furnace. This measurement allows for the determination of the dry weight of the fines and the dry binder.

[0056] Detailed description of the invention

[0057] The present invention proposes a method for preparing a catalyst from catalyst fines.

[0058] The thin ones

[0059] Catalyst fines can originate from a fresh, used, regenerated and / or rejuvenated catalyst. They can also originate from a fresh, used, regenerated and / or rejuvenated capture mass.

[0060] Preferably, the fines come from a fresh or regenerated catalyst. Preferably, the fines come from a regenerated catalyst.

[0061] According to a first embodiment, the fines can originate from a fresh catalyst. This term refers to a catalyst that has not already been used in production, but which is generally out of specification, for example because it contains an insufficient metal content or too low a mechanical resistance, or is smaller than the required size resulting from the various unit operations of manufacturing new catalysts.

[0062] According to a second embodiment, the fines can originate from a spent catalyst. A "spent" catalyst is understood to be one that is at least partially spent, meaning one that has already been used in production, particularly in hydrotreating or hydroconversion plants such as hydrocracking. A "spent" catalyst is specifically understood to include one that is at least partially spent but has not been regenerated or rejuvenated. The spent catalyst may contain coke and / or sulfur as described above. The spent catalyst may undergo a deoiling step before grinding.

[0063] The oil removal step generally involves contacting the spent catalyst with a stream of inert gas (i.e., essentially oxygen-free), for example in a nitrogen or similar atmosphere, at a temperature between 300°C and 400°C, preferably between 300°C and 350°C. The inert gas flow rate, in terms of flow rate per unit volume of catalyst, is 5 to 150 NL.IT 1 for 3 to 7 hours. Alternatively, the oil removal step can be carried out using light hydrocarbons, by steam treatment or any other similar process.

[0064] According to a third embodiment, the fines can come from a regenerated catalyst. This term refers to a used catalyst, possibly de-oiled, which has undergone a coke and sulfur removal step: a regeneration step, which removes all or part of the coke, sulfur and / or chlorine that may have been deposited on the catalyst.

[0065] The regeneration step is generally carried out in a gas stream containing oxygen, usually air. The water content in the gas is typically between 0 and 50% by weight. The gas flow rate, measured in terms of flow rate per unit volume of the at least partially spent catalyst, is preferably 20 to 2000 NL.IT 1 , preferably from 30 to 1000 NL.h-1, and particularly preferably from 40 to 500 NL.tr 1 The regeneration period is preferably 2 hours or more, more preferably 2.5 hours or more, and particularly preferably 3 hours or more. Regeneration of the spent catalyst, possibly de-oiled, is generally carried out at a temperature between 320°C and 550°C, preferably between 360°C and 500°C.

[0066] According to a fourth embodiment, the fines can originate from a rejuvenated catalyst. This term refers to a regenerated catalyst that has been re-impregnated with a solution containing metallic precursors and / or organic or inorganic additives.

[0067] Fines can be naturally produced during the various stages of catalyst manufacturing or during the loading or unloading of a catalyst from the industrial unit from which it is removed.

[0068] Fines can also be produced during regeneration. Indeed, the quantity of fines produced during regeneration is generally quite high due to the damage caused to the catalyst structure by the high temperature of the regeneration process.

[0069] Fines can also be deliberately produced, for example by grinding a fresh, oversized (or not) catalyst or a used, regenerated, and / or rejuvenated catalyst. An important feature of the invention is that the catalyst fines are in the form of reasonably small particles or in a powdery form so as to allow the catalyst fines to be mixed with other components to provide a mixture that can be shaped or agglomerated.

[0070] Therefore, fines with a D90 size that is too large, or the catalyst used to produce fines, are subjected to a preliminary grinding step if necessary. It is, of course, possible to carry out several successive grinding steps to achieve the desired particle size D90. Any method known to those skilled in the art can be implemented to perform this crushing or grinding step, such as, for example, the use of a ball mill or a blade mill.In this case, the grinding step is carried out in such a way as to obtain fines having a D90 size less than or equal to 500 micrometers, preferably less than 300 micrometers, or even less than 200 micrometers, preferably between 1 and 500 micrometers, preferably between 1 and 300 micrometers, preferably between 1 and 200 micrometers, or even between 1 and 160 micrometers or between 1 and 100 micrometers, even more preferably between 1 and 60 micrometers, and particularly preferably between 1 and 20 micrometers.

[0071] The D90 size is defined as follows: 90% of the volume population of fines has an equivalent diameter less than or equal to 500 micrometers, preferably less than 300 micrometers, or even less than 200 micrometers, and generally between 1 and 500 micrometers, preferably between 1 and 300 micrometers, preferably between 1 and 200 micrometers, or even between 1 and 160 micrometers or between 1 and 100 micrometers, even more preferably between 1 and 60 micrometers, and particularly preferably between 1 and 20 micrometers. The equivalent diameter, denoted "de", is defined according to the following relationship: de = 6V / S, where V is the volume of the particle and S is the surface area of ​​the sphere with the same volume as the particle.

[0072] The particle size distribution of fines is measured by laser diffraction particle size analysis according to ASTM D4464. This technique is based on the principle of light diffraction. Suspended particles (in a solvent such as water or in an air stream) diffract the light emitted by a laser beam contained within the instrument. The spatial distribution of this light, a function of particle size, is recorded by an array of photodiodes. Analysis of this distribution in the focal plane allows the proportion of each size class to be determined, leading to knowledge of the grain size distribution within the sample. The fines have the same composition as the catalysts from which they originate.Fines, whether originating from a fresh, spent, regenerated, and / or rejuvenated catalyst, comprise at least one oxide carrier, at least one Group VIII metal and / or at least one Group VI B metal, and optionally phosphorus and optionally an organic compound comprising oxygen and / or nitrogen and / or sulfur. They may also, but are not limited to, include coke and / or sulfur, particularly when they are fines originating from a regenerated or spent catalyst.

[0073] The oxide support is usually a porous solid selected from the group consisting of: aluminas, silica, silica-aluminas, or titanium or magnesium oxides used alone or in mixtures with alumina or silica-alumina. Preferably, the oxide support consists essentially of at least one transition alumina, that is, it comprises at least 51 wt%, preferably at least 60 wt%, most preferably at least 80 wt%, or even at least 90 wt%, of transition alumina. It is preferably composed solely of a transition alumina. Preferably, the oxide support of said catalyst is a gamma-phase alumina.

[0074] In another preferred case, the oxide present in the oxide support is a silica-alumina containing at least 50% alumina by weight relative to the total weight of the composite support. The silica content in the support is at most 50% by weight relative to the total weight of the support, most often less than or equal to 45% by weight, preferably less than or equal to 40% by weight.

[0075] According to a particularly preferred variant, the oxide support consists of alumina, silica, or silica-alumina.

[0076] The oxide carrier may also advantageously contain an additional 0.1 to 80% by weight, preferably 0.1 to 50% by weight, of zeolite relative to the total weight of the carrier. In this case, all known sources of zeolite and associated preparation methods may be incorporated. Preferably, the zeolite is selected from the FAU, BEA, ISV, IWR, IWW, MEI, and UWY groups, and even more preferably, the zeolite is selected from the FAU and BEA groups, such as Y and / or beta zeolite, and particularly preferably, such as USY and / or beta zeolite.

[0077] The oxide support advantageously has a total pore volume between 0.1 and 1.5 mL / g, preferably between 0.4 and 1.1 mL / g. The total pore volume is measured by mercury porosimetry according to ASTM D4284-92 with a wetting angle of 140°, for example, using a Micromeritics™ Autopore III™ instrument. The specific surface area of ​​the oxide support is advantageously between 5 and 400 m². 2 .g- 1 preferably between 10 and 350 m 2 .g- 1 , preferably between 40 and 350 m 2 .g- 1 The specific surface area is determined in the present invention by the BET method according to ASTM D3663.

[0078] The active phase of the fines comprises at least one metal from Group VI B and / or at least one metal from Group VIII. The Group VI B metal is preferably chosen from molybdenum and tungsten, or a mixture of these two elements. The Group VIII metal is preferably chosen from cobalt, nickel, and a mixture of these two elements. The active phase is preferably chosen from the group formed by the combination of nickel-molybdenum, cobalt-molybdenum, nickel-cobalt-molybdenum, nickel-tungsten, nickel-molybdenum-tungsten, and nickel-cobalt-tungsten.

[0079] The Group VIII metal content is between 1 and 50% by weight of Group VIII metal oxide relative to the weight of the fines, preferably between 1.5 and 9% by weight, and preferably between 2 and 8% by weight. When the metal is cobalt or nickel, the metal content is expressed as CoO and NiO, respectively.

[0080] The metal content of Group VIB is between 5 and 40 wt% of the oxide of the Group VIB metal relative to the total weight of the fines, preferably between 8 and 35 wt%, and most preferably between 10 and 30 wt%. When the metal is molybdenum or tungsten, the metal content is expressed as MoO₂ and WO₃, respectively.

[0081] The molar ratio of group VIII metal to group VIB metal in fines, when these contain both types of metals, is preferably between 0.1 and 0.8, preferably between 0.15 and 0.6 and even more preferably between 0.2 and 0.6 or between 0.3 and 0.5.

[0082] The fines may also contain phosphorus as a dopant. A dopant is an added element that, in itself, has no catalytic properties but increases the catalytic activity of the active phase.

[0083] The phosphorus content is then preferably between 0.1 and 20% by weight expressed as P2O5 relative to the total weight of fines, preferably between 0.2 and 15% by weight expressed as P2O5, and very preferably between 0.3 and 8% by weight expressed as P2O5.

[0084] The phosphorus-to-group VIB molar ratio is greater than or equal to 0.05, preferably greater than or equal to 0.07, preferably between 0.08 and 1, preferably between 0.01 and 0.9, and most preferably between 0.15 and 0.6. The fines may contain sulfur. The sulfur content is then less than 15% by weight, preferably between 1 and 15% by weight expressed as an element relative to the total weight of the fines, preferably between 2 and 12%, and most preferably between 4 and 10% by weight. The sulfur content is measured by elemental analysis according to ASTM D5373.

[0085] The fines may include coke, particularly when they originate from a spent catalyst that has not been regenerated. It should be noted that the term "coke" in this application refers to a hydrocarbon-based substance deposited on the surface of the catalyst during its use, highly cyclized and condensed, and having an appearance similar to graphite.

[0086] The coke content, expressed as a percentage by weight of carbon, is less than 20% by weight and may be between 2% and 20% by weight, preferably between 3% and 16% by weight, and in particular between 4% and 14% by weight, relative to the total weight of the fines. The coke content is determined according to ASTM D5373.

[0087] Preferably, the fines contain little or no sulfur. The sulfur content is then preferably less than 5% by weight, preferably between 0.1% and 3% by weight, preferably between 0.1% and 2% by weight, and particularly preferably between 0.1% and 0.8% by weight relative to the total weight of the fines. The fines may also be sulfur-free.

[0088] Preferably, the fines contain little or no coke. The coke content is then preferably less than 5% by weight, preferably between 0.1% and 4% by weight, preferably between 0.1% and 2% by weight, and particularly preferably between 0.1% and 1% by weight, or even between 0.1% and 0.5% by weight, relative to the total weight of the fines. The fines may also contain no coke at all.

[0089] Optionally, the fines may also have a low content of contaminants from the feed treated by the spent or regenerated catalyst from which it originates, such as nickel (contaminant), vanadium, iron, titanium, silicon, calcium, sodium, potassium, chlorine and arsenic.

[0090] Preferably, the silicon content (in addition to that possibly present by the silica of the support) is less than 2% by weight and very preferably less than 1% by weight relative to the weight of the fines.

[0091] Preferably, the arsenic content is less than 2000 ppm by weight and, most preferably, less than 1000 ppm by weight relative to the weight of the fines. Preferably, the content of each metal—nickel, vanadium, iron—is less than 1% by weight and, most preferably, less than 5000 ppm by weight relative to the weight of the fines.

[0092] Preferably, the fines are not contaminated, meaning they contain less than 100 ppm by weight of silicon (excluding any silicon present in the oxide support), less than 100 ppm by weight of sodium (excluding any sodium present in the oxide support), less than 50 ppm by weight of arsenic, less than 50 ppm by weight of iron, less than 50 ppm by weight of chlorine, less than 2000 ppm by weight of vanadium, and less than 2000 ppm by weight of nickel (contamination). This can be the case, in particular, when the fines originate from a fresh or regenerated catalyst.

[0093] The fines used in the mixing in step a) of the process according to the invention can be wet or dry. When wet, the loss on ignition of the fines is between 0.1 and 50%, preferably between 0.5 and 40%, and most preferably between 1 and 30%.

[0094] All the contents of the different components of the fines are expressed on the basis of the weight of the dry fines.

[0095] The inorganic oxide binder

[0096] According to the invention, the catalyst prepared by the process according to the invention may contain a binder. This binder may advantageously be amorphous or crystalline. Preferably, this binder is advantageously selected from the group formed by the following oxides or their hydrated forms: alumina, silica, silica-alumina, clays, titanium dioxide, boron dioxide, and zirconia, alone or in mixtures. Preferably, this binder is alumina or an aluminum hydroxide, alone or in mixtures. Preferably, this binder is alumina in all its forms known to those skilled in the art, such as, for example, alpha, gamma, eta, and delta aluminas, or hydroxides such as boehmite, bayerite, or gibbsite. These aluminas differ in their specific surface area and pore volume. Preferably, the inorganic oxide binder is alumina or boehmite.

[0097] The inorganic oxide binder used in the mixture in step a) of the process according to the invention can be wet or dry. When wet, the loss on ignition of the binder is between 5 and 80%, preferably between 6 and 70%, and preferably between 7 and 50%.

[0098] Catalyst preparation

[0099] Step a) Mixing fines and extrusion aid agent According to step a), the said fines and an extrusion aid agent are mixed, and optionally an inorganic oxide binder.

[0100] According to a preferred preparation method, the fines, the agent, and optionally the binder, can be mixed, without limitation, in the form of powder, ground powder, suspension, or a suspension that has undergone a deagglomeration treatment. Said fines, the agent, and optionally the binder, can advantageously be mixed by mechanical blending or by suspension at a concentration adjusted to the final fines content and optionally the binder content targeted in the catalyst prepared according to the present invention.

[0101] The extrusion aid facilitates subsequent extrusion. The content of the extrusion aid is between 0.1 and 10% by weight, preferably between 0.1 and 5% by weight, and even more preferably between 0.1 and 3% by weight, relative to the weight of the dry fines and the optional dry inorganic oxide binder introduced in step a).

[0102] The extrusion aid can be methylcellulose, for example Methocel™, cellulose, carboxymethylcellulose, or carboxyethylcellulose. Preferably, the extrusion aid is methylcellulose (Methocel™).

[0103] Other extrusion shaping additives may also be added. Such additives include, for example, tall oil, xanthan gums, a surfactant, a flocculant such as polyacrylamides, carbon black, starches, stearic acid, polyacrylic alcohol, polyvinyl alcohol, biopolymers, glucose and polyethylene glycols.

[0104] The fines are introduced into the mixture in step a) so that the fines content is between 10% and 100% by weight of the catalyst obtained at the end of step e), preferably between 50% and 100% by weight, and most preferably between 75% and 100% by weight. The fines content in the catalyst obtained at the end of step e) is expressed on the basis of the dry weight of the fines.

[0105] Since the active phase is provided by the fines in the catalyst obtained according to the process according to the invention, it is advantageous to integrate a high rate of fines incorporation into the catalyst in order to obtain high activity and / or to avoid having to reintroduce metals by impregnation afterwards.

[0106] The inorganic oxide binder is introduced into the mixture in step a) such that the inorganic oxide binder content is between 0% and 90% by weight of the catalyst obtained at the end of step e), preferably between 0% and 50% by weight, and most preferably between 0% and 25% by weight. The inorganic oxide binder content in the catalyst obtained at the end of step e) is expressed on a weight basis of the dry binder. The mixture in step a) may not contain any inorganic oxide binder.

[0107] Step b) Peptization / kneading

[0108] According to step b), the mixture obtained in step a) is kneaded by adding an aqueous solution containing a carboxylic acid. This produces a paste.

[0109] Carboxylic acid is a peptizing agent. The presence of a peptizing agent leads to the formation of a paste that is subsequently extruded. The peptizing agent also minimizes macroporosity in the resulting catalyst and improves its mechanical strength.

[0110] The carboxylic acid is chosen from formic acid, acetic acid, oxalic acid, citric acid, and γ-ketovaleric acid, alone or in mixtures. Preferably, the carboxylic acid is citric acid.

[0111] The quantity of carboxylic acid added can advantageously be defined by a total acid content, expressed as a percentage relative to the weight of fines and possibly binder introduced in step a). The total acid content is between 0.1 and 20 wt%, preferably between 0.1 and 10 wt%, and most preferably between 1 and 9 wt%.

[0112] Water may also be introduced during step b), so that the loss on ignition of the mixture is between 20 and 80%, preferably between 30 and 70%, and particularly preferably between 30 and 60%.

[0113] The mixing can advantageously be carried out by any conventional, commercially available tool.

[0114] The kneading time is generally between 1 minute and 1 hour, preferably between 5 and 30 minutes.

[0115] In one embodiment according to the invention, the aqueous solution containing a carboxylic acid further contains at least one organic compound having complexing (but not acidic) properties.

[0116] The organic compound (or at least one of them when there are several) exhibiting complexing properties may be chosen from at least one of the following compounds: dimethylglyoxime, methyl acetoacetate, ethyl acetoacetate, ethyl lactate, methyl glycolate, ethyl glycolate, dimethyl malate, diethyl malate, dimethyl tartrate, diethyl tartrate, ethyl 3-hydroxybutanoate, ethyl 3-ethoxypropanoate, methyl 3-methoxypropanoate, methyl 3-(methylthio)propanoate, ethyl 3-(methylthio)propanoate, ethylene glycol, diethylene glycol, triethylene glycol, a polyethylene glycol (with a molecular weight between 200 and 1500 g / mol), propylene glycol, glycerol, 2-butoxyethanol, 2-(2-butoxyethoxy)ethanol, 2-(2-methoxyethoxy)ethanol, triethylene glycol dimethyl ether, a crown ether, acetophenone, 2,4-pentanedione, pentanone, glucose, fructose, sucrose,sorbitol, xylitol, mannitol, γ-valerolactone, propylene carbonate, octylamine, N,-diethylformamide, N,N-dimethylformamide, N-methylformamide, N,N-dimethylacetamide, propanamide, 1-methyl-2-pyrrolidinone, tetramethylurea, N,N'-dimethylurea, acetonitrile, lactamide, furfurol, 2-furaldehyde, 5-hydroxymethylfurfural, ethyl 3-hydroxybutanoate, 2-hydroxyethyl acrylate, 1-vinyl-2-pyrrolidinone, N,N,N',N'-tetramethyltartramide, 3-hydroxypropionitrile and N,N'-bis(2-hydroxyethyl)ethylenediamine.

[0117] According to a preferred variant, the organic compound exhibiting complexing properties is chosen from fructose, ethylene glycol, diethylene glycol, and triethylene glycol.

[0118] The concentration of each organic compound exhibiting complexing properties of the aqueous solution containing a carboxylic acid is generally between 0.03 and 2 mol / L, preferably between 0.1 and 1.3 mol / L, and particularly preferably between 0.5 and 1 mol / L.

[0119] Step c) Neutralization (optional)

[0120] A neutralization step c) can be carried out after the peptization step b) by adding to the mixture obtained in step b) a neutralizing agent chosen from an inorganic base or an organic base.

[0121] The inorganic base is chosen from sodium hydroxide, potassium hydroxide, and ammonia, alone or in mixtures, and the organic base is chosen from amines and quaternary ammonium compounds, alone or in mixtures. Preferably, the organic base is chosen from alkylethanolamines and ethoxylated alkylamines. The organic base is preferably used in aqueous solution. Most preferably, the neutralizing agent is an inorganic base, and preferably ammonia.

[0122] The quantity of neutralizing agent can be defined by a neutralization rate expressed as a molar percentage of base relative to the number of moles of protons present in step b) and is between 1 and 100%. Preferably, the neutralization rate expressed as a molar percentage of base relative to the number of moles of protons is between 20 and 60%.

[0123] Water may also be introduced during the neutralization step, so that the loss on ignition of the mixture is between 20 and 80%, preferably between 30 and 70%, and particularly preferably between 30 and 60%.

[0124] When the neutralization step by adding the neutralizing agent is carried out, the mixing is maintained under the conditions described above.

[0125] Step d): Shaping by extrusion

[0126] According to step d), shaping is carried out by extrusion of the mixture obtained in step b) of peptisation, or of the mixture obtained in step c) of neutralisation when present, to obtain a solid.

[0127] Extrusion can advantageously be carried out using any commercially available conventional tool. The mixture from step b) or c) is advantageously extruded through a die, for example, using a piston or a single or twin screw extrusion die. This extrusion step can advantageously be carried out by any method known to those skilled in the art for obtaining a solid. The extrudates can be multilobed, for example, trilobed or quadrilobed.

[0128] Step e) Drying

[0129] According to step e) of the process, the solid obtained in step d) is dried at a temperature below 200°C, advantageously between 50°C and 180°C, preferably between 70°C and 150°C, most preferably between 80°C and 140°C, without subsequent calcination, in order to obtain a catalyst.

[0130] The drying step can be carried out by any technique known to those skilled in the art. It is advantageously carried out at atmospheric pressure or reduced pressure. Preferably, this step is carried out at atmospheric pressure. It is advantageously carried out in a flow bed using air or any other hot gas. Preferably, when drying is carried out in a fixed bed, the gas used is either air or an inert gas such as argon or nitrogen. Most preferably, drying is carried out in a flow bed in the presence of nitrogen and / or air. Preferably, the drying step has a duration of between 5 minutes and 24 hours, preferably between 30 minutes and 10 hours, and most preferably between 1 hour and 8 hours.The drying is carried out in such a way as to retain preferably at least 30% by weight of the carboxylic acid introduced during the peptization step, preferably this quantity is greater than 50% by weight and even more preferably greater than 70% by weight, calculated on the basis of the carbon remaining on the catalyst obtained.

[0131] It is important to emphasize that the catalyst obtained by the process according to the invention does not undergo calcination after drying in order to preserve at least part of the carboxylic acid in the catalyst. Calcination is defined here as heat treatment under a gas containing air or oxygen at a temperature of 200°C or higher.

[0132] Step f) Introduction of active phase (optional)

[0133] Depending on the application of the catalyst and its target metal contents of groups VI B and / or VIII, the process according to the invention may include a step f) of introducing one or more precursors of an active phase onto the catalyst obtained in step e). This may be the case in particular when the binder introduction rate is high.

[0134] Thus, according to the optional step f) of the preparation process according to the invention, at least one metal from group VIB and / or at least one metal from group VIII, and optionally phosphorus, and / or at least one organic compound comprising oxygen and / or nitrogen and / or sulfur, is brought into contact with said catalyst obtained after step e) of drying.

[0135] The group VIB metal and / or group VIII metal(s) introduced in this step (f) may be the same as or different from the group VIB metal and group VIII metal already introduced by the fines. A metal not present in the fines may be introduced.

[0136] The molar ratio of group VIII metal to group VIB metal in the final catalyst is generally between 0.1 and 0.8, preferably between 0.15 and 0.6.

[0137] The contacting of at least one metal from Group VIB and / or at least one metal from Group VIII with said catalyst may advantageously be carried out by any technique known to those skilled in the art, such as ion exchange, dry impregnation, excess impregnation, vapor deposition, etc. The contacting may take place in one step or in several successive steps. According to a preferred method, said contacting step(s) is / are carried out by the so-called "dry" impregnation method well known to those skilled in the art by contacting an impregnation solution containing a metal from Group VIII and / or a metal from Group VIB with said catalyst.

[0138] The contacting process advantageously involves a precursor of the aforementioned metals. For example, molybdenum sources include oxides and hydroxides, molybdic acids and their salts, particularly ammonium salts such as ammonium molybdate, ammonium heptamolybdate, phosphomolybdic acid (H3PM012O4O), and their salts, and possibly silicomolybdic acid (H4SiMoI2O4O) and its salts. Molybdenum sources can also include any heteropolycompound of the Keggin, lacunar Keggin, substituted Keggin, Dawson, Anderson, and Strandberg types, for example. Molybdenum trioxide and heteropolycompounds of the Keggin, lacunar Keggin, substituted Keggin, and Strandberg types are preferred.

[0139] The tungsten precursors that can be used are also well known to those skilled in the art. For example, tungsten sources include oxides and hydroxides, tungstic acids and their salts, particularly ammonium salts such as ammonium tungstate, ammonium metatungstate, phosphotungstic acid and their salts, and possibly silicotungstic acid (H4SiWi2O4O) and its salts. Tungsten sources can also be any heteropolycompound of the Keggin, lacunar Keggin, substituted Keggin, or Dawson type, for example. Ammonium oxides and salts such as ammonium metatungstate or heteropolyanions of the Keggin, lacunar Keggin, or substituted Keggin type are preferred.

[0140] Cobalt precursors that can be used are advantageously chosen from among oxides, hydroxides, hydroxycarbonates, carbonates, and nitrates, for example. Cobalt hydroxide and cobalt carbonate are preferred.

[0141] Nickel precursors that can be used are advantageously chosen from among oxides, hydroxides, hydroxycarbonates, carbonates and nitrates, for example.

[0142] Any impregnation solution described in the present invention may comprise any polar protic solvent known to those skilled in the art. Preferably, a polar protic solvent is used, for example, one chosen from the group consisting of methanol, ethanol, and water. Preferably, the solvent used in the impregnation solution is water.

[0143] According to another variant, the contacting step f) may also include contacting said catalyst obtained after the drying step e) with an impregnation solution containing phosphorus, in addition to the metal from group VI B and / or the metal from group VIII.

[0144] The total phosphorus-to-Group VIB metal molar ratio in the catalyst is greater than or equal to 0.05, preferably greater than or equal to 0.07, preferably between 0.08 and 1, preferably between 0.1 and 0.9, and most preferably between 0.15 and 0.6. The preferred phosphorus precursor is orthophosphoric acid (H3PO4), but its salts and esters, such as ammonium phosphates, are also suitable. Phosphorus may also be introduced along with the Group VIB element(s) in the form of Keggin, lacunar Keggin, substituted Keggin, or Strandberg-type heteropolyanions.

[0145] According to yet another variant, the contacting step (f) may also include contacting the catalyst obtained after the drying step with an impregnation solution containing an organic compound containing oxygen and / or nitrogen and / or sulfur, in addition to the Group VI B metal, the Group VIII metal, and possibly phosphorus. The function of the additives or organic compounds is to increase the catalytic activity compared to the unadditized catalysts. The organic compound is preferentially impregnated onto the catalyst after solubilization in aqueous or non-aqueous solution.

[0146] In this case, the total molar ratio of the organic compound to the group VI B metal in solution is between 0.01 and 5 mol / mol, preferably between 0.05 and 3 mol / mol, preferably between 0.05 and 2 mol / mol and most preferably between 0.1 and 1.5 mol / mol.

[0147] When several organic compounds are present, the different molar ratios apply to each of the organic compounds present.

[0148] Generally, the organic compound is chosen from a compound containing one or more chemical functions chosen from a carboxylic, alcohol, thiol, thioether, sulfone, sulfoxide, ether, aldehyde, ketone, ester, carbonate, amine, nitrile, imide, oxime, urea and amide function, or a compound including a furanic ring or a sugar.

[0149] Preferably, it is chosen from among γ-valerolactone, 2-acetylbutyrolactone, triethylene glycol, diethylene glycol, ethylene glycol, ethylenediaminetetraacetic acid (EDTA), formic acid, acetic acid, oxalic acid, maleic acid, malonic acid, citric acid, gluconic acid, dimethyl succinate, glucose, fructose, sucrose, sorbitol, xylitol, γ-ketovaleric acid, dimethylformamide, 1-methyl-2-pyrrolidinone, propylene carbonate, 2-methoxyethyl 3-oxobutanoate, bicine, tricine, 2-furaldehyde (also known as furfural), 5-hydroxymethylfurfural (also known as 5-(hydroxymethyl)-2-furaldehyde or 5-HMF), 2-acetylfuran, 5-methyl-2-furaldehyde, ascorbic acid, butyl lactate, ethyl 3-hydroxybutanoate, ethyl 3-ethoxypropanoate, 2-ethoxyethyl acetate, 2-butoxyethyl acetate, 2-hydroxyethyl acrylate, 1-vinyl-2-pyrrolidinone,1,3-Dimethyl-2-imidazolidinone, 1-(2-hydroxyethyl)-2-pyrrolidinone, 1-(2-hydroxyethyl)-2,5-pyrrolidinedione, 5-methyl-2(3H)-furanone, 1-methyl-2-piperidinone and 4-aminobutanoic acid.

[0150] Preferably, the organic compound is chosen from formic acid, acetic acid, oxalic acid, citric acid, γ-ketovaleric acid, fructose, ethylene glycol, diethylene glycol, and triethylene glycol.

[0151] The organic compound introduced in this way may be identical or different from the carboxylic acid introduced during step b) of peptization and / or identical or different from the organic compound having complexing properties possibly introduced during step b) and maintained during drying in step e). Preferably it is identical.

[0152] The impregnation step has several implementation methods. These are distinguished primarily by the timing of the introduction of the organic compound, if present, which can be carried out either simultaneously with the impregnation of the metals (co-impregnation), afterward (post-impregnation), or before (pre-impregnation). Furthermore, implementation methods can be combined.

[0153] Advantageously, after each impregnation step, the impregnated substrate is allowed to mature. Maturation allows the impregnation solution to disperse homogeneously within the substrate.

[0154] Each maturation step described in the present invention is advantageously carried out at atmospheric pressure, in a water-saturated atmosphere, and at a temperature between 17°C and 50°C, and preferably at ambient temperature. Generally, a maturation time of between ten minutes and forty-eight hours, and preferably between thirty minutes and six hours, is sufficient.

[0155] After the impregnation step(s) and any subsequent maturation step(s), the catalyst is generally dried at a temperature below 200°C, advantageously between 50°C and 180°C, preferably between 70°C and 150°C, and most preferably between 75°C and 130°C, without subsequent calcination, so as to obtain a dried catalyst. The drying step can be carried out by any technique known to those skilled in the art, as described above.

[0156] According to one variant, and advantageously when an organic compound is present, the drying is carried out in such a way as to retain preferably at least 30% by weight of the organic compound introduced during an impregnation step, preferably this amount is greater than 50% by weight, and even more preferably, greater than 70% by weight, calculated on the basis of the carbon remaining on the catalyst. As with drying step e), it is important to emphasize that the catalyst obtained at the end of step f) does not undergo calcination after drying in order to preserve at least part of the carboxylic acid and possibly the organic compound with complexing properties introduced during step b), and possibly the organic compound containing oxygen and / or nitrogen and / or sulfur introduced during the optional step f) into the catalyst.Here, calcination is understood as a heat treatment under a gas containing air or oxygen at a temperature greater than or equal to 200°C.

[0157] Before its use in a hydrotreating and / or hydrocracking reaction, it is advantageous to transform the catalyst obtained according to the process of the invention, optionally supplemented by impregnation with an active phase of a Group VI B metal and / or a Group VIII metal, phosphorus, and an organic compound, into a sulfide catalyst in order to form its active species. 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.

[0158] At the end of the drying step e) or after the possible introduction of the active phase of step f) of the process according to the invention, said catalyst is therefore advantageously subjected to a sulfidation step, without an intermediate calcination step.

[0159] The catalyst is advantageously sulfided ex situ or in situ. Sulfurizing agents include hydrogen sulfide (H₂S), 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 to sulfidate the catalyst. These sulfur-containing compounds are advantageously selected from alkyl disulfides, such as dimethyl disulfide (DMDS), alkyl sulfides, such as dimethyl sulfide, thiols, such as n-butylmercaptan (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.Preferably the catalyst is sulfided in situ in the presence of a hydrocarbon feed supplemented with dimethyl disulfide.

[0160] Characteristics of the catalyst obtained

[0161] The preparation process according to the present invention makes it possible to obtain a catalyst comprising at least one oxide support, at least one metal from Group VIII and / or at least one metal from Group VI B (derived from the fines and optionally introduced after the drying step e)), a carboxylic acid (introduced as a peptizing agent), and optionally phosphorus (derived from the fines or optionally introduced during step f)), and optionally another organic compound comprising oxygen and / or nitrogen and / or sulfur (derived from the fines or introduced during step f) or introduced in step b). The catalyst obtained according to the process of the invention may also include, but is not limited to, coke and / or sulfur, particularly when derived from the fines of a regenerated or spent catalyst.

[0162] The Group VIII metal content is between 0.5 and 50% by weight of Group VIII metal oxide relative to the weight of the catalyst, preferably between 1.5 and 9% by weight, and preferably between 2 and 8% by weight.

[0163] The content of group VI B metal is between 2.5 and 40% by weight of group VI B metal oxide relative to the weight of the catalyst, preferably between 8 and 35% by weight, most preferably between 10 and 30% by weight.

[0164] The molar ratio of group VIII metal to group VI B metal in the catalyst, when it contains both types of metals, is preferably between 0.1 and 0.8, preferably between 0.15 and 0.6 and even more preferably between 0.2 and 0.6 or between 0.3 and 0.5.

[0165] The phosphorus content is then preferably between 0.05 and 20% by weight expressed as P2O5 relative to the weight of the catalyst, preferably between 0.2 and 15% by weight expressed as P2O5, and most preferably between 0.3 and 8% by weight expressed as P2O5.

[0166] The molar ratio of phosphorus to the group VI B element is greater than or equal to 0.05, preferably greater than or equal to 0.07, preferably between 0.08 and 1, preferably between 0.01 and 0.9 and most preferably between 0.15 and 0.6.

[0167] The sulfur content may be between 0 and 15% by weight, expressed as an element relative to the weight of the catalyst, preferably between 1 and 12%, and most preferably between 2 and 10% by weight. Preferably, the catalyst contains little or no sulfur. In this case, the sulfur content is preferably less than 5% by weight, preferably between 0.1% and 3% by weight, preferably between 0.1% and 2% by weight, and most preferably between 0.1% and 0.8% by weight. The catalyst may also be sulfur-free.

[0168] The coke content, expressed as a percentage by weight of the carbon element, may be between 0 and 20% by weight, preferably between 1.5 and 16% by weight, and particularly between 2 and 14% by weight relative to the weight of the catalyst. Preferably, the catalyst contains little or no coke. The coke content is then preferably less than 5% by weight, preferably between 0.1% and 4% by weight, preferably between 0.1% and 2% by weight, and particularly preferably between 0.1% and 1% by weight, or even between 0.1% and 0.5% by weight. The catalyst may also be coke-free.

[0169] The preparation process according to the present invention has in particular the advantage of leading to a catalyst having a very satisfactory mechanical resistance in relation to the porous volumes which characterize it, said resistance being materialized by the value of the grain-to-grain EGG crushing, of at least 0.4 daN / mm preferably of at least 0.7 daN / mm, most preferably of at least 0.8 daN / mm.

[0170] The preparation process according to the present invention makes it possible to obtain a catalyst advantageously having a total pore volume, as measured by mercury porosimeter intrusion, of between 0.1 and 1.5 ml / g and preferably between 0.2 and 1.1 ml / g

[0171] The mesoporous volume of the catalyst prepared according to the invention, i.e. contained in the pores with a diameter between 2 and 50 nm, as measured by intrusion with a mercury porosimeter, is between 0.1 and 0.7 ml / g and preferably between 0.1 and 0.5 ml / g.

[0172] The macroporous volume of the catalyst prepared according to the invention, i.e. contained in the pores with a diameter greater than 50 nm, as measured by intrusion with a mercury porosimeter, is between 0 and 0.4 ml / g and preferably between 0 and 0.2 ml / g and most preferably between 0 and 0.1 ml / g, and particularly preferably between 0 and 0.08 ml / g.

[0173] The catalyst prepared according to the invention generally has a specific surface area of ​​between 5 and 400 m² 2 / g, preferably between 10 and 350 m 2 / g, preferably between 40 and 350 m 2 / g, preferably between 150 and 340 m 2 / g.

[0174] Hydrotreating and / or hydrocracking process

[0175] The catalyst obtained according to the process of the invention can be used in hydrotreating and / or hydrocracking processes of hydrocarbon fractions and more particularly for hydrogenation, hydrodeazotation, hydrodearomatization, hydrodesulfurization, hydrodeoxygenation, hydrodemetallation or hydroconversion reactions of hydrocarbon feedstocks.

[0176] The hydrotreating and / or hydrocracking process for hydrocarbon fractions can be carried out in one or more reactors in series, either of the fixed-bed or bubbling-bed type. The hydrocarbon feedstock targeted by hydrotreating and / or hydroconversion can be of various types. It may be of fossil origin or derived from the conversion of biomass or waste, either alone or in mixtures. The feedstocks treated, and in particular those listed below, generally contain heteroatoms such as sulfur, oxygen, and nitrogen, and, for heavy feedstocks, they most often also contain metals.

[0177] Fossil fuel feedstock typically consists of a fraction derived from coal or hydrocarbons produced from natural gas, possibly in mixtures. It can also include heavy petroleum or synthetic fractions, such as kerosene, diesel, or distillates obtained through atmospheric and vacuum distillation to produce usable kerosene, diesel, or vacuum distillate. This usable product is then either stored in a pool receiving similar products or sent to a downstream unit, such as a catalytic cracking unit, where the feedstock is cracked to produce shorter-chain hydrocarbons. Hydrotreating is often a preliminary step in the hydroconversion / hydrocracking process of treating a feedstock.

[0178] The fossil fuel feedstocks used in a hydrotreating process, in more detail, are for example gasoline, diesel, vacuum diesel, atmospheric residues, vacuum residues, atmospheric distillates, vacuum distillates, heavy fuel oils, oils, waxes and paraffins, used oils, residues or deasphalted crudes, feedstocks from thermal or catalytic conversion processes, taken alone or in mixtures.

[0179] The feedstock resulting from biomass conversion may advantageously be selected from vegetable oils, algae or seaweed oils, fish oils, used cooking oils, and fats of vegetable or animal origin; or mixtures of such feedstocks. Said vegetable oils may advantageously be crude or refined, wholly or partially, and derived from plants selected from rapeseed, sunflower, soybean, palm, olive, coconut, copra, castor, cottonseed, peanut, linseed, and crambe oils, and all oils derived, for example, from sunflower or rapeseed by genetic modification or hybridization, this list not being exhaustive. Said animal fats are advantageously selected from lard and fats composed of residues from the food industry or from the catering industry.Frying oils, various animal oils such as fish oil, tallow, and lard can also be used. The feedstock from biomass conversion can also advantageously be chosen from among methyl esters of fatty acids of vegetable and / or animal origin, or from methyl esters of fatty acids from used edible vegetable oils. Tl.

[0180] The feedstock resulting from biomass conversion can also be selected from feedstocks produced by thermal or catalytic biomass conversion processes, such as oils derived from biomass, particularly lignocellulosic biomass, using various liquefaction methods, such as hydrothermal liquefaction or pyrolysis. The term "biomass" refers to material derived from recently living organisms, including plants, animals, and their byproducts. The term "lignocellulosic biomass" refers to biomass derived from plants or their byproducts. Lignocellulosic biomass is composed of carbohydrate polymers (cellulose, hemicellulose) and an aromatic polymer (lignin).

[0181] The feedstock from biomass conversion can also advantageously be chosen from feedstocks from the paper industry.

[0182] The feedstock resulting from waste conversion can be pyrolysis oil derived from plastics, tires, or solid recovered fuels (SRF). These oils are obtained through thermal pyrolysis, catalytic pyrolysis, or hydropyrolysis (pyrolysis in the presence of a catalyst and hydrogen).

[0183] The operating conditions used in the processes implementing the hydrotreating reactions of hydrocarbon feedstocks described above are generally as follows: the temperature is advantageously between 180 and 450°C, and preferably between 250 and 440°C; the pressure is advantageously between 0.5 and 30 MPa, and preferably between 1 and 18 MPa; the hourly volumetric velocity is advantageously between 0.1 and 20 h' 1 and preferably between 0.2 and 5 hours 1and 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 to 5000 l / l and preferably 80 to 2000 l / l.

[0184] According to a first embodiment, the hydrotreating process is a hydrotreating process, and in particular a hydrodesulfurization (HDS) process, of a diesel fraction carried out in the presence of at least one catalyst obtained according to the invention. The hydrotreating process aims to eliminate sulfur compounds present in the diesel fraction in order to meet current environmental standards, namely an authorized sulfur content of up to 10 ppm. It also reduces the aromatic and nitrogen content of the diesel fraction to be hydrotreated.

[0185] The said diesel cut to be hydrotreated contains from 0.02 to 5.0% by weight of sulfur. It is advantageously obtained from direct distillation (or straight run diesel, according to Anglo-Saxon terminology), a coking unit, a visbreaking unit, a steam cracking unit, a hydrotreating and / or hydrocracking unit for heavier feedstocks, and / or a fluid catalytic cracking unit. This diesel cut preferably contains at least 90% of the compounds with a boiling point between 250°C and 400°C at atmospheric pressure.

[0186] The hydrotreating process for said diesel fraction is implemented under the following operating conditions: a temperature between 200 and 400°C, preferably between 300 and 380°C; a total pressure between 2 MPa and 10 MPa, and more preferably between 3 MPa and 8 MPa; a hydrogen volume to hydrocarbon feed volume ratio, expressed as hydrogen volume measured under standard temperature and pressure conditions, per liquid feed volume, between 100 and 600 liters per liter, and more preferably between 200 and 400 liters per liter; and an hourly volumetric rate (WH) between 1 and 10 h -1 preferably between 2 and 8 am -1The WH corresponds to the inverse of the contact time expressed in hours and is defined by the ratio of the volumetric flow rate of liquid hydrocarbon feedstock to the volume of catalyst loaded into the reaction unit implementing the hydrotreating process according to the invention. The reaction unit implementing the hydrotreating process of said diesel fraction is preferably operated as a fixed bed, a moving bed, or a bubbling bed, preferably as a fixed bed.

[0187] According to a second embodiment, the hydrotreating and / or hydrocracking process is a hydrotreating (in particular hydrodesulfurization, hydrodeazotation, aromatic hydrogenation) and / or hydrocracking process of a distillate fraction under vacuum, carried out in the presence of at least one catalyst obtained according to the invention. This hydrotreating and / or hydrocracking process, also called a hydrocracking pretreatment process or hydrocracking process, aims, as appropriate, to remove sulfur, nitrogen, or aromatic compounds present in the distillate fraction in order to perform pretreatment before conversion in catalytic cracking or hydroconversion processes, or to hydrocrack the distillate fraction that may have been pretreated beforehand, if necessary.

[0188] A wide variety of feedstocks can be treated by the vacuum hydrotreating and / or hydrocracking processes of distillates described above. These feedstocks typically contain at least 20% by volume and often at least 80% by volume of compounds boiling above 340°C at atmospheric pressure. Examples of feedstocks include vacuum distillates, feedstocks from aromatic extraction units of lubricating oil bases, feedstocks from solvent dewaxing of lubricating oil bases, and / or deasphalted oils. Alternatively, the feedstock may be deasphalted oil, paraffins from the Fischer-Tropsch process, or any mixture of the aforementioned feedstocks.In general, feedstocks have a boiling point (T5) above 340°C at atmospheric pressure, and preferably above 370°C at atmospheric pressure; that is, 95% of the compounds present in the feedstock have a boiling point above 340°C, and preferably above 370°C. The nitrogen content of the feedstocks treated in the processes according to the invention is usually greater than 200 ppm by weight, preferably between 500 and 10,000 ppm by weight. The sulfur content of the feedstocks treated in the processes according to the invention is usually between 0.01 and 5.0% by weight. The feedstock may optionally contain metals (for example, nickel and vanadium). The asphaltene content is generally less than 3,000 ppm by weight.

[0189] The catalyst obtained according to the invention is generally brought into contact, in the presence of hydrogen, with the charges described above, at a temperature above 200°C, often between 250°C and 480°C, advantageously between 320°C and 450°C, preferably between 330°C and 435°C, under a pressure above 1 MPa, often between 2 and 25 MPa, preferably between 3 and 20 MPa, the volumetric velocity being between 0.1 and 20.0 h' 1 and preferably 0.1-6.0 h' 1 , preferably, 0.2-3.0 h' 1and the quantity of hydrogen introduced is such that the volume ratio of liters of hydrogen to liters of hydrocarbon, expressed as volume of hydrogen, measured under normal temperature and pressure conditions, per volume of liquid feed, is between 80 and 5,000 l / l and most often between 100 and 2,000 l / l. These operating conditions used in the processes according to the invention generally make it possible to achieve conversions per pass, in products having boiling points below 340°C at atmospheric pressure, and preferably below 370°C at atmospheric pressure, of more than 15% and even more preferably between 20 and 95%.

[0190] The vacuum hydrotreating and / or hydrocracking processes for distillates using the catalysts obtained according to the invention cover pressure and conversion ranges from mild hydrocracking to high-pressure hydrocracking. Mild hydrocracking is defined as hydrocracking that results in moderate conversions, generally less than 40%, and operates at low pressure, typically between 2 MPa and 6 MPa.

[0191] The catalyst obtained according to the invention can be used alone, in one or more fixed-bed catalytic beds, in one or more reactors, in a so-called one-stage hydrocracking scheme, with or without liquid recycling of the unconverted fraction, or in a so-called two-stage hydrocracking scheme, possibly in association with a hydrorefining catalyst located upstream or downstream of said catalyst.

[0192] According to a third application, the hydrotreating and / or hydrocracking process is advantageously implemented as a pretreatment in a fluidized bed catalytic cracking (FCC) process. The operating conditions of the pretreatment, in terms of temperature range, pressure, hydrogen recycling rate, and hourly volumetric rate, are generally identical to those described above for vacuum hydrotreating and / or hydrocracking of distillates. The FCC process can be carried out in a conventional manner known to those skilled in the art under suitable cracking conditions to produce lower molecular weight hydrocarbon products. A summary description of catalytic cracking can be found, for example, in Ullman's Encyclopedia of Industrial Chemistry, Volume A, 18, 1991, pages 61 to 64.

[0193] According to a fourth mode of use, said hydrotreating and / or hydrocracking process according to the invention is a hydrotreating process (in particular hydrodesulfurization) of a gasoline cut in the presence of at least one catalyst obtained according to the invention.

[0194] Unlike other hydrotreating processes, the hydrotreating (especially hydrodesulfurization) of gasoline must meet a dual antagonistic constraint: ensuring deep hydrodesulfurization of gasoline and limiting the hydrogenation of unsaturated compounds present in order to limit the loss of octane rating.

[0195] The feedstock is generally a hydrocarbon fraction with a distillation range between 30 and 260°C. Preferably, this hydrocarbon fraction is a gasoline fraction. Most preferably, the gasoline fraction is an olefinic gasoline fraction obtained, for example, from a fluid catalytic cracking unit.

[0196] The hydrotreating process consists of bringing the hydrocarbon fraction into contact with the catalyst and hydrogen under the following conditions: at a temperature between 200 and 400°C, preferably between 230 and 330°C, at a total pressure between 1 and 3 MPa, preferably between 1.5 and 2.5 MPa, at a Volumetric Rate of Flow (WH), defined as the volumetric flow rate of feed relative to the volume of catalyst, between 1 and 10 h -1 preferably between 2 and 6 hours -1and at a hydrogen / gasoline charge volume ratio of between 100 and 600 Nl / L, preferably between 200 and 400 Nl / L. The gasoline hydrotreating process can be carried out in one or more reactors in series of the fixed bed or bubbling bed type. If the process is implemented using at least two reactors in series, it is possible to provide a device for removing FhS from the effluent from the first hydrodesulfurization reactor before treating said effluent in the second hydrodesulfurization reactor.

[0197] Although the present invention relates to a process for preparing a catalyst for use in hydrocarbon hydrotreating and / or hydrocracking units, it is understood that the process according to the invention applies to the preparation of any catalyst comprising at least one metal from Group VIII and / or at least one metal from Group VI B, and an oxide support, such as, for example, selective hydrogenation catalysts, hydrotreating catalysts for residues (for example, carried out in a boiling bed) or Fischer-Tropsch catalysts.

[0198] It is also possible to use fines which do not have the same function as the catalyst prepared by the process according to the invention, as long as the fines and the catalyst produced have at least one metal in common (hydrotreating catalyst, hydrocracking catalyst, Fischer-Tropsch catalyst).

[0199] Examples

[0200] We start with a spent catalyst called CoMoP, containing molybdenum, cobalt and phosphorus deposited on an alumina support used in a hydrotreating process. It has previously been regenerated under a flow of dry air at 450°C for 4 hours.

[0201] The regenerated catalyst contains molybdenum, phosphorus and cobalt. The composition of the catalyst is expressed in the form of oxides and referred to the mass of dry catalyst: 21.6% wt MoOa (14.4% wt molybdenum), 3.7% wt CoO (2.9% wt cobalt, i.e. a molar ratio Co / Mo of 0.33) and 3.2% wt P2O5 (1.4% wt phosphorus, i.e. a molar ratio P / Mo of 0.3).

[0202] Example 1: Preparation of catalyst A according to the invention

[0203] To prepare catalyst A, the regenerated C0M0 catalyst is ground to a particle size such that the D90 is equal to 30 µm. The fines are introduced with 3 wt% Methocel™ into a closed vessel of a Brabender-type cam-arm mixer. A peptizing agent, citric acid (CeHsO₄), is added to reach an acid content of 10%. Water is also gradually added to achieve a loss on ignition (LOI) of 40%, the value being adjusted according to the formulation to obtain a homogeneous and cohesive paste. The paste is mixed for 15 minutes and then extruded using a piston extruder through a 1.8 mm diameter die. The resulting extrudates are dried (16 hours at 80°C in an air-ventilated oven). The characteristics of the catalyst A obtained are given in Table 1.

[0204] Example 2: Non-compliant preparation of catalyst B

[0205] To prepare Catalyst B, the regenerated CoMo catalyst is ground to a particle size such that the D90 is equal to 30 µm. The fines are introduced with 2 wt% Methocel™ into a closed vessel of a Brabender-type cam-arm mixer. A peptizing agent, nitric acid (HNO3), is added to reach an acid content of 1%. Water is also gradually added to achieve a loss on ignition (LOI) of 40%, the value being adjusted according to the formulation to obtain a homogeneous and cohesive paste. The paste is mixed for 30 min and then extruded using a piston extruder through a 1.8 mm diameter die. The resulting extrudates are dried (16 hours at 80°C in an air-ventilated oven). The characteristics of the resulting Catalyst B are given in Table 1.

[0206] Example 3: Preparation of non-compliant catalyst C

[0207] To prepare catalyst C, the regenerated CoMo catalyst is ground to a fine particle size of 70 µm (D90). This fine particle size is mixed with 2 wt% Methocel™ into a closed vessel of a Brabender-type cam-arm mixer. Citric acid (CeHsO₄) is added to achieve an acid concentration of 6%. Water is gradually added to achieve a loss on ignition (LOI) of 40%, with the specific value adjusted according to the formulation to obtain a homogeneous and cohesive paste. The paste is mixed for 10 minutes and then extruded using a piston extruder through a 1.8 mm diameter die. The resulting extrudates are dried (16 hours at 80°C in a ventilated oven under air) and then calcined at 450°C for 4 hours under dry air. The characteristics of the resulting catalyst C are given in Table 1.

[0208] Example 4: Preparation of catalyst D according to the invention

[0209] To prepare catalyst D, the regenerated CoMo catalyst is ground to a fine particle size of 60 µm, where D90 is 60 µm. 27 g of this fine particle size is mixed with 9 g of alumina (binder) and 2 wt% Methocel™ in a closed vessel of a Brabender-type cam-arm mixer. Citric acid (CeHsO₄) is added to achieve an acid content of 5%. Water is gradually added to achieve a loss on ignition (LOI) of 47%, with the specific value adjusted according to the formulation to obtain a homogeneous and cohesive paste. The paste is mixed for 30 minutes, after which an ammonia solution is gradually introduced to neutralize 40% of the acidity and achieve a loss on ignition (LOI) of 49%. The dough is then kneaded for another 15 minutes and then extruded using a piston extruder through a 1.8 mm diameter die. The resulting extrudates are dried for 16 hours at 80°C in a ventilated oven.The characteristics of the catalyst D obtained are given in Table 1.

[0210] Example 5: Preparation of non-compliant catalyst E

[0211] To prepare catalyst E, the regenerated CoMo catalyst is ground to a particle size where the D90 is 70 µm. 29 g of fines are introduced, along with 13 g of boehmite (binder) and 3 wt% Methocel™, into a closed vessel of a Brabender-type cam-arm mixer. Nitric acid (HNO3), a peptizing agent, is added to achieve an acid content of 3%. Water is also gradually added to reach a loss on ignition (LOI) of 46%, the value being adjusted according to the formulation to obtain a homogeneous and cohesive paste. The paste is mixed for 30 min, then an ammonia solution is gradually added to neutralize 30% of the acidity and achieve a loss on ignition (LOI) of 48%. The dough is then kneaded for another 15 minutes and then extruded using a piston extruder through a 1.8 mm diameter die. The resulting extrudates are dried for 16 hours at 80°C in a ventilated oven.The characteristics of the catalyst E obtained are given in Table 1.

[0212] Example 6: Preparation of non-compliant catalyst F

[0213] To prepare catalyst F, the regenerated CoMo catalyst is ground to a particle size where the D90 is 70 µm. Sixteen grams of fines are introduced, along with 22 grams of boehmite (binder) and 3 wt% Methocel™, into a closed vessel of a Brabender-type cam-arm mixer. A peptizing agent, citric acid (CeHsO₄), is added to achieve an acid content of 4%. Water is also gradually added to reach a loss on ignition (LOI) of 52%, the value being adjusted according to the formulation to obtain a homogeneous and cohesive paste. The paste is mixed for 30 minutes, and then an ammonia solution is gradually added to neutralize 50% of the acidity and achieve a loss on ignition (LOI) of 54%. The dough is then kneaded for another 15 minutes and then extruded using a piston extruder through a die with a diameter of 1.8 mm.The resulting extrudates are dried (16 hours at 80°C in a ventilated oven under air) and then calcined at 450°C for 4 hours under dry air. The characteristics of the resulting catalyst F are given in Table 1.

[0214] Table 1 below summarizes the characteristics of the synthesized catalysts A to F. Table 1

[0215] Example 7: Non-compliant preparation of catalyst G

[0216] The catalyst A obtained after drying is calcined at 450°C for 4 hours under dry air. This yields catalyst G. Example 8: Preparation of non-compliant catalyst H

[0217] The catalyst D obtained after drying is calcined at 450°C for 4 hours under dry air. This yields catalyst H.

[0218] Example 9: Evaluation of diesel fuel hydrodesulfurization (HDS) of catalysts A and D (according to the invention) and B, C, E, F, G, and H (not according to the invention). Catalysts A and D (according to the invention) and B, C, E, F, G, and H (not according to the invention) were tested in diesel fuel hydrodesulfurization. The regenerated catalyst was also tested and serves as a reference. The characteristics of the diesel fuel used are as follows: density at 15 °C = 0.8522 g / cm³ 3 , sulfur content = 1.44% by weight.

[0219] Simulated Distillation (ASTM D2887):

[0220] PI: 155 °C

[0221] 10%: 247 °C

[0222] 50%: 315 °C

[0223] 90%: 392 °C

[0224] PF: 444 °C

[0225] The test is conducted in a pilot isothermal flow-through fixed-bed reactor, with fluids flowing from bottom to top.

[0226] The catalysts are first sulfided in situ at 350°C in the pressurized reactor using the test diesel fuel to which 2% by weight of dimethyl disulfide is added.

[0227] The hydrodesulfurization tests were conducted under the following operating conditions: a total pressure of 7 MPa, a catalyst volume of 30 cm³ 3 , a temperature of 330 to 360°C, with a hydrogen flow rate of 24 l / h and a charging flow rate of 60 cm 3 / h.

[0228] The catalytic performance of the tested catalysts is given in Table 2. It is expressed in degrees Celsius relative to the regenerated catalyst chosen as a reference: it corresponds to the temperature difference required to reach 50 ppm of sulfur in the effluent. A negative value means that the target sulfur content is reached at a lower temperature, thus resulting in increased activity.

[0229] Table 2

[0230] Catalyst A (according to the invention) exhibits improved activity compared to catalyst C prepared with a final calcination step or catalyst B prepared from an inorganic acid. Catalyst A (according to the invention) also exhibits improved activity compared to catalyst G prepared in a strictly identical manner with a final calcination step.

[0231] Catalyst D (according to the invention) exhibits improved activity compared to catalyst F prepared with a final calcination step or catalyst E prepared from an inorganic acid. Catalyst D (according to the invention) also exhibits improved activity compared to catalyst H prepared in a strictly identical manner with a final calcination step.

Claims

DEMANDS 1. A process for preparing a catalyst from catalyst fines comprising at least one metal from Group VIB and / or at least one metal from Group VIII, and an oxide support, said fines having a D90 size less than or equal to 500 micrometers, the process comprising at least the following steps: a) mixing said fines with an extrusion aid, and optionally an inorganic oxide binder, b) kneading the mixture obtained in step a) by adding an aqueous solution containing a carboxylic acid, c) optionally adding to said mixture obtained in step b) a neutralizing agent selected from an inorganic base and an organic base, d) shaping the mixture obtained in step b) or c) by extrusion to obtain a solid, e) drying the solid obtained in step d) at a temperature below 200°C, without subsequent calcination.

2. A method according to claim 1, wherein the D90 size of the fines is less than 300 micrometers.

3. A process according to any one of the preceding claims, wherein the fines content is between 10% and 100% relative to the weight of the catalyst prepared by the process according to the invention.

4. A process according to any one of the preceding claims, wherein the fines have a group VIB metal content of between 5 and 40% by weight of oxide of group VIB metal and a group VIII metal content of between 1 and 50% by weight of oxide of group VIII metal relative to the weight of the fines.

5. A process according to any one of the preceding claims, wherein the fine oxide support is selected from alumina, silica, silica-alumina, titanium oxide or magnesium oxide used alone or in mixture with alumina or silica-alumina.

6. A method according to any one of the preceding claims, wherein said inorganic oxide binder is present and is selected from the group formed by the following oxides or their hydrated forms: alumina, silica, silica-alumina, clays, titanium oxide, boron oxide and zirconia, taken alone or in mixture.

7. A process according to any one of the preceding claims, wherein the content of the extrusion aid agent is between 0.1 and 10% weight relative to the weight of the dry fines and the optional dry inorganic oxide binder introduced in step a).

8. A method according to any one of the preceding claims, wherein the extrusion aid agent is selected from methylcellulose, cellulose, carboxy-methyl-cellulose, carboxy-ethyl-cellulose.

9. A process according to any one of the preceding claims, wherein the carboxylic acid is selected from formic acid, acetic acid, oxalic acid, citric acid, γ-ketovaleric acid, alone or in mixture.

10. A process according to any one of the preceding claims, wherein the amount of carboxylic acid added is defined by a total acid content, expressed as a percentage relative to the weight of the dry fines and the optional dry inorganic oxide binder introduced in step a) and is between 0.1 and 20 wt%.

11. A process according to any one of the preceding claims, wherein the aqueous solution containing a carboxylic acid further contains at least one organic compound having complexing properties.

12. A process according to any one of the preceding claims, wherein when step c) is carried out, said mixture obtained in step b) is added a neutralizing agent selected from an inorganic base and an organic base, said inorganic base being selected from sodium hydroxide, potassium hydroxide, and ammonia, alone or in mixture and said organic base being selected from amines and quaternary ammonium compounds alone or in mixture.

13. A method according to any one of the preceding claims, wherein the quantity of neutralizing agent is defined by a neutralization rate expressed as a base molar percentage relative to the number of moles of protons present in step b) and is between 1 and 100%.

14. A process according to any one of the preceding claims, which includes a step (f), in which at least one metal from Group VI B and / or at least one metal from Group VIII, and optionally phosphorus and / or at least one organic compound comprising oxygen and / or nitrogen and / or sulfur, is contacted with said catalyst obtained after step (e) of drying, the contacting being followed by a drying step at a temperature below 200°C, without subsequent calcination.

15. A process according to any one of the preceding claims, wherein said catalyst obtained after the drying step e) or after the step f) is subjected to a sulfidation step, without an intermediate calcination step.

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