Process for sulfidizing hydrocarbon treatment catalyst

Abstract

The object of the present invention is a process for the sulfidation treatment of a hydrocarbon treatment catalyst comprising: (i) at least one step of contacting the catalyst with an emulsion comprising: (ia) an aqueous phase comprising at least one acid; and (ib) an organic phase; and then (ii) at least one step of contacting the catalyst with a sulfur-containing gas mixture comprising hydrogen and sulfides. The invention also relates to a process for treating a used catalyst, such a sulfidation treatment being carried out after a regeneration step.

Description

Technical Field

[0001] The present invention relates to a process for sulfiding a catalyst, which is used for treating hydrocarbons in the refining and petrochemical fields in particular, using an emulsion containing an acidic aqueous phase and an organic phase. Background Art

[0002] The hydrocarbon treatment processes carried out in refineries and / or petrochemical plants include a certain number of treatment processes carried out in the presence of hydrogen, which are used to change the structure of hydrocarbon molecules and / or remove hydrocarbon fractions from unwanted compounds, such as (in particular) sulfides, nitrides, oxides, aromatic compounds, metal compounds. As non-limiting examples, hydrocracking or hydroconversion, reforming, isomerization, alkylation, hydrogenation, dehydrogenation processes and so-called hydrotreating processes, such as hydrodesulfurization, hydrodenitrogenation, dearomatization, demetallization, hydrodeoxygenation processes, can be cited.

[0003] These processes require specific catalysts, which are in the form of small particles (or catalyst particles) and include a porous support based on one or more refractory inorganic oxides, on which one or more catalytically active metals are deposited. These metals more commonly include one or more Group VIII metals of the periodic table, and / or one or more Group VIB metals.

[0004] At the end of the production of the catalyst, or at the end of the regeneration of the used catalyst, the metal is in the form of a metal oxide, that is, inactive.

[0005] In order to activate the catalyst in the various processes for treating hydrocarbons, the catalyst needs to be sulfided, that is, treated with a sulfide, aiming to convert the metal oxide into the mixed sulfides constituting the active phase of the catalyst.

[0006] This sulfiding step is particularly important because it regulates the activity of the catalyst in its subsequent use.

[0007] The prior art has described many sulfiding processes, such as gas-phase sulfiding processes, in which the catalyst is treated with a sulfur-containing gas mixture (usually in the form of hydrogen sulfide).

[0008] Thus, patent application EP 1634939 describes a sulfiding process carried out in the gas phase with a gas containing hydrogen sulfide (H2S) and hydrogen (H2), with an H2S / H2 molar ratio greater than 4 and a partial pressure of H2S of at least 1 kPa.

[0009] Many methods have been described to improve the performance of these sulfiding processes.

[0010] Thus, patent application EP 0993868 describes a process for in-situ ex-sulfiding a catalyst for hydroconverting hydrocarbons in the presence of hydrogen and at least one sulfide. The process is characterized in that, prior to the sulfiding treatment, the catalyst is preferably contacted with at least one liquid hydrocarbon.

[0011] Patent application EP 1077085 describes a sulfiding treatment process, which is characterized in that the catalyst is pre-carbonated in order to deposit most of the non-leachable carbonic compounds in its pores.

[0012] Furthermore, patent application EP 1272 272 describes a sulfiding treatment process for a catalyst comprising at least one Group VI and / or VIII hydro-metals and an organic additive, wherein the catalyst is contacted with an organic liquid in a first stage and then with hydrogen and a sulfur-containing gas compound in a second stage, provided that at least 40% of the sulfur in the sulfided catalyst is provided by the organic liquid.

[0013] Furthermore, it is known to use a sulfiding treatment aid (such as an organic acid), which is deposited on the surface of the catalyst prior to the sulfiding step.

[0014] Thus, application EP 2295 521 describes a process for sulfiding a hydrocarbon treatment catalyst, comprising a first step of depositing an unsaturated dicarboxylic acid of a specific chemical formula on the surface of the catalyst, and then a second step of gas-phase sulfiding. The catalyst is impregnated with an aqueous solution containing the acid to deposit the acid thereon, and then a drying step is carried out to remove the moisture.

[0015] Application EP 2295 522 describes a similar process, wherein a thio-carboxylic acid is deposited during the first step.

[0016] Continuing the research on sulfiding hydrotreating catalysts, the applicant has now found that the catalyst can be treated with a specific emulsion prior to the sulfiding treatment step to improve the gas-phase sulfiding process. The present invention is based on this discovery. Summary of the Invention

[0017] Thus, the object of the present invention is a process for sulfiding a hydrocarbon treatment catalyst, comprising: (i) at least one step of contacting the catalyst with an emulsion, said emulsion comprising: (ia) an aqueous phase containing at least one acid; and (ib) an organic phase; and then (ii) at least one step of contacting the catalyst with a sulfur-containing gas mixture comprising hydrogen and a sulfide.

[0018] Compared with the prior art processes, the process according to the present invention can increase the degree of sulfidation of the catalyst.

[0019] It can also significantly increase the activity of the catalyst.

[0020] Furthermore, compared with a hypothetical process (not described in the prior art) which would include a step of depositing an acidic sulfurization promoter in aqueous solution and a step of impregnating a liquid hydrocarbon, the process according to the present invention has proven to significantly reduce the phenomenon of unwanted catalyst consumption.

[0021] In a manner known per se, the consumption of catalyst particles is related to the mechanical abrasion of said particles, especially during the transportation, handling and use of the catalyst, due to vibrations and / or crushing, the friction between the particles with each other or with the walls of the container that houses them, which causes mechanical abrasion. This phenomenon leads to damage to the particles and an unwanted decrease in their size, and also leads to the formation of fines (i.e., unwanted dust particles).

[0022] The process according to the present invention is suitable for sulfiding both new hydrotreating catalysts and used hydrotreating catalysts that have been previously regenerated. It is particularly suitable for sulfiding used catalysts that have been previously regenerated.

[0023] Therefore, another object of the present invention is a process for treating a used hydrotreating catalyst, implementing the specific sulfiding process described in the present application after the regeneration step. So, this treatment method includes a step of regenerating the catalyst by heat treatment at a temperature of 350 °C to 550 °C in the presence of oxygen, and then performing the sulfiding process according to the present invention.

[0024] Other objects, features, aspects and advantages of the present invention will become clearer after reading the following description.

[0025] Hereinafter, unless otherwise specified, the boundaries of numerical ranges are included within the range, especially the expressions "including... and... between" and "the range from... to...".

[0026] Moreover, the expressions "at least one" and "at least" used in this specification are respectively equivalent to the expressions "one or more" and "greater than or equal to".

[0027] Finally, in a manner known per se, C N A compound or group represents a compound or group containing N carbon atoms in its chemical structure.

[0028] aqueous phase (ia) of the emulsion The emulsion used in step (i) of the process according to the present invention includes an aqueous phase (ia).

[0029] The aqueous phase comprises water and one or more acids, which may be selected from inorganic acids and organic acids. It is generally presented in the form of an acid solution in water.

[0030] The acid may be in the form of a free acid or a salified form, for example, in the form of alkali metal salts such as sodium and potassium salts, and alkaline earth metal salts such as magnesium salts and ammonium salts.

[0031] Any water-soluble acid can be used at the temperature at which step (i) is carried out.

[0032] Among the available inorganic acids, phosphoric acid (H3PO4), metaphosphoric acid (HPO3) and pyrophosphoric acid (H4P2O7) can be particularly cited.

[0033] According to a preferred embodiment, the aqueous phase comprises one or more organic acids, preferably selected from carboxylic acids.

[0034] The carboxylic acids that can be used in the present invention generally contain 1 to 10 carbon atoms. In addition to carbon atoms, the carboxylic acids may include hydrogen and oxygen atoms, and heteroatoms such as sulfur and nitrogen.

[0035] These carboxylic acids can be advantageously selected from monocarboxylic acids, dicarboxylic acids, tricarboxylic acids, amino polycarboxylic acids and mixtures thereof.

[0036] Among the monocarboxylic acids, monocarboxylic acids having the chemical formula R-COOH can be particularly cited, where R represents a saturated or unsaturated hydrocarbon group containing 1 to 9 carbon atoms and optionally one or more heteroatoms such as sulfur, oxygen and nitrogen. By way of example of these acids, formic acid (methanoic acid), acetic acid (ethanoic acid), lactic acid, glycolic acid, crotonic acid, acrylic acid, thioacids (such as 2-hydroxy-4-(methylthio)butyric acid), mercaptoacetic acid, amino acids (such as 2-aminoacetic acid (glycine)) can be cited.

[0037] Among the dicarboxylic acids, malic acid, maleic acid, malonic acid, itaconic acid, oxalic acid, mesoxalic acid, fumaric acid, succinic acid, tartaric acid, glutaric acid, ketoglutaric acid, iminodiacetic acid, galactaric acid (mucic acid), adipic acid, diglycolic acid, valeric acid and mixtures thereof can be particularly cited.

[0038] Among the tricarboxylic acids, citric acid, isocitric acid, aconitic acid, oxalosuccinic acid can be particularly cited.

[0039] Among the amino polycarboxylic acids, ethylenediaminetetraacetic acid (EDTA), nitrilotriacetic acid (NTA), diethylenetriaminepentaacetic acid (DTPA) can be particularly used.

[0040] The carboxylic acids are preferably selected from glycolic acid, mercaptoacetic acid, maleic acid, citric acid and mixtures thereof.

[0041] According to a particularly preferred embodiment, the aqueous phase comprises citric acid.

[0042] Preferably, relative to the weight of the aqueous phase, the aqueous phase comprises an acid in a weight content of 5% to 50%, more preferably 15% to 30%.

[0043] This content is expressed in the form of non-salified, free acid.

[0044] Moreover, the acid advantageously accounts for 3 wt%-30 wt% of the total weight of the emulsion, preferably 5 wt%-20 wt%.

[0045] This content is expressed in the form of non-salified, free acid.

[0046] Advantageously, the pH of the aqueous phase is in the range of 1 to 7, preferably in the range of 1.5 to 3.

[0047] By volume, the aqueous phase preferably accounts for 40%-70% of the total volume of the emulsion, more preferably 50%-60%.

[0048] organic phase (ib) of the emulsion The emulsion used in step (i) of the process according to the invention comprises an organic phase (ib).

[0049] "Organic phase" means any non-aqueous phase that is less than 1 wt%, preferably less than 0.5 wt% water-soluble at ambient temperature (25 °C) and atmospheric pressure (760 mm Hg).

[0050] Preferably, the organic phase is liquid at ambient temperature and atmospheric pressure.

[0051] Advantageously, the organic phase comprises one or more oils, preferably selected from compounds and compound mixtures comprising at least one chain having at least 8 carbon atoms. The oil can in particular be selected from vegetable oils, animal oils, mineral oils, synthetic oils and mixtures thereof.

[0052] As vegetable oils, for example, castor oil, sunflower oil, peanut oil, soybean oil, rapeseed oil, copra oil, corn oil, palm oil, linseed oil and safflower oil can be cited.

[0053] Used edible oils can also be cited, which can comprise vegetable oils and / or animal oils.

[0054] Suitable mineral oils are especially selected from: liquid hydrocarbons and hydrocarbon mixtures derived from distillates of oils, such as (especially and in a non-limiting manner) fuels and / or combustible fractions, such as gasoline, jet oil, naphtha, diesel oil, fuel oil fractions; lubricating oil fractions, for example oils sold under the name "150 Neutral"; solvent fractions, such as those fractions named "white spirits".

[0055] Preferred mineral oils are selected from diesel fractions (especially including atmospheric distillation diesel and vacuum distillation diesel) and solvent fractions (selected from C8 to C 14 paraffins, C8 to C 14 naphthenes, aromatic hydrocarbons, and mixtures thereof).

[0056] These hydrocarbon mixtures can be (if applicable) subjected to one or more hydrotreating processes, such as hydrodesulfurization, isomerization, etc.

[0057] As synthetic oils, polyalpha-olefins (such as polydecenes and polyisobutenes), hydrocarbons and hydrocarbon mixtures obtained by synthesis (such as by the Fischer-Tropsch synthesis process or hydrotreating of vegetable oils), and transesterified vegetable oils can be cited.

[0058] According to a preferred embodiment, the organic phase comprises one or more of the above-mentioned mineral oils and / or one or more vegetable oils.

[0059] The organic phase may also comprise one or more solid fats at ambient temperature, such as waxes.

[0060] As examples of waxes that can be used in the present invention, waxes of animal origin (such as beeswax), plant waxes (such as sunflower wax), mineral waxes (such as paraffin wax, petrolatum), synthetic waxes (such as polyethylene wax, waxes derived from the Fischer-Tropsch synthesis), and mixtures thereof can be cited.

[0061] By volume, the organic phase preferably accounts for 30% - 60% of the total volume of the emulsion, more preferably 40% - 50%.

[0062] sulfide (optional) According to a preferred embodiment, the emulsion further comprises one or more sulfides, which can be selected from organic sulfides and inorganic sulfides.

[0063] When the emulsion contains one or more inorganic sulfides, these sulfides are advantageously present in the aqueous phase of the emulsion. Thus, according to a preferred embodiment of the present invention, the aqueous phase contains one or more sulfides, preferably selected from inorganic sulfides.

[0064] The inorganic sulfides can be especially selected from thiosulfates (such as sodium thiosulfate, potassium thiosulfate, ammonium thiosulfate), metabisulfites (such as sodium metabisulfite, potassium metabisulfite, ammonium metabisulfite), and elemental sulfur (the latter is advantageously suspended in the aqueous phase).

[0065] When the emulsion contains one or more organic sulfides, these sulfides are advantageously present in the organic phase of the emulsion. Thus, according to a preferred embodiment of the present invention, the organic phase (ib) contains one or more sulfides, preferably selected from organic sulfides.

[0066] The organic sulfides can be especially selected from polysulfides, mercaptans (thiols), thiophene, and sulfoxides.

[0067] The polysulfides are especially selected from compounds of the formula R-S n -R’, where: -n is an integer ranging from 3 to 20, preferably 3 to 8, more preferably 3 to 7, and -R and R’ are the same or different and represent organic groups containing 1 to 150 carbon atoms, preferably 10 to 60 carbon atoms, more preferably 15 to 30 carbon atoms; R’ can also represent hydrogen. These groups can be saturated or unsaturated, straight-chain, branched-chain or cyclic, and can be selected from the group consisting of alkyl, alkenyl, aryl, alkylaryl radicals, and arylalkyl radicals, and these groups can include at least one heteroatom.

[0068] As an example of a polysulfide, the di-tert-butyl polysulfide of the formula (CH3)3C-S4-C(CH3)3 can be cited.

[0069] The mercaptans are especially selected from compounds of the formula R-SH, where R represents an organic group containing 1 to 150 carbon atoms, preferably 10 to 60 carbon atoms, more preferably 8 to 30 carbon atoms. This group can be saturated or unsaturated, straight-chain, branched-chain or cyclic, and can be selected from the group consisting of alkyl, alkenyl, aryl, alkylaryl, and arylalkyl, and these groups can include at least one heteroatom.

[0070] As an example of a mercaptan, the nonyl mercaptan of the formula CH3(CH2)7CH2-SH can be cited.

[0071] The sulfoxides are especially selected from compounds of the formula R-SO-R', where R and R' are the same or different and represent organic groups containing from 1 to 150 carbon atoms, preferably 10 to 60 carbon atoms, more preferably 15 to 30 carbon atoms; R' can also represent hydrogen. These groups can be saturated or unsaturated, straight-chain, branched or cyclic, and can be selected from the group consisting of alkyl, alkenyl, aryl, alkaryl and aralkyl groups, and these groups can include at least one heteroatom.

[0072] As an example of a sulfoxide, mention may be made of dodecyl methyl sulfoxide of the formula CH3(CH2) 10 CH2-SO-CH3.

[0073] Of course, mixtures of the organic sulfides described above can be used.

[0074] Generally speaking, the sulfide is advantageously present in an amount of 4 wt% - 12 wt%, preferably 6 wt% - 10 wt% of the total weight of the emulsion.

[0075] According to a preferred embodiment, the organic phase of the emulsion comprises one or more of the organic sulfides described above, more preferably selected from polysulfides, thiols, sulfoxides, and mixtures of these compounds, still more preferably selected from polysulfides.

[0076] In this embodiment, the organic sulfide advantageously accounts for 10 wt% - 40 wt%, preferably 15 wt% - 25 wt% of the total weight of the organic phase.

[0077] emulsion The emulsion used in step (i) of the process according to the invention can be a direct emulsion (i.e., of the water-in-oil type, with the organic phase dispersed in the aqueous phase) or an indirect emulsion (i.e., of the oil-in-water type, with the aqueous phase dispersed in the organic phase).

[0078] Preferably, the emulsion is a direct emulsion, i.e., the organic phase is dispersed in the aqueous phase.

[0079] According to a preferred embodiment, the emulsion further comprises one or more surfactants.

[0080] The surfactant can advantageously be selected from anionic surfactants, non-ionic surfactants, amphoteric surfactants and mixtures thereof, more preferably from non-ionic surfactants.

[0081] As examples of suitable non-ionic surfactants, the following may be mentioned: - alkoxylated alkyl (C8 - C 24 ) phenols; - saturated or unsaturated, straight-chain or branched, alkoxylated or glycerolated C8 to C30 Alcohols, and containing one or two fatty chains; - Saturated or unsaturated, straight-chain or branched C8 to C 30 Acid esters, as well as polyhydric alcohol or polyethylene glycol esters; - Saturated or unsaturated, straight-chain or branched C8 to C 30 Esters of acids and esters of sorbitol, preferably oxyethylated; - Fatty acid and sucrose esters; - Alkyl (C8-C 30 ), glycopyranosides and alkenyl (C8-C 30 ), glycopyranosides, possibly alkoxylated (0 to 10 oxyalkylene units) and containing 1 to 15 glucose units; alkyl (C8-C 30 ), glycopyranoside esters; - Saturated or unsaturated, oxyethylated vegetable oils; - Ethylene oxide and / or propylene oxide condensates; - And mixtures thereof; The alkoxylated units are especially oxyethylated, oxypropylated units, or combinations thereof, preferably oxyethylated.

[0082] The molar number of ethylene oxide and / or propylene oxide is preferably 1 to 250, more preferably 2 to 100; more preferably 2 to 50; the molar number of glycerol is especially 1 to 50, more preferably 1 to 10.

[0083] The non-ionic surfactant is more preferably selected from C8 to C containing 1 to 40 moles of ethylene oxide 24 Oxyethylated alcohols, preferably 2 to 20 moles of ethylene oxide.

[0084] The total content of the surfactant preferably accounts for 0.1 wt% to 5 wt% of the total weight of the emulsion, more preferably 0.2 wt% to 2.5 wt%, even more preferably 0.5 wt% to 1.5 wt%.

[0085] step (i) Step (i) consists of bringing the catalyst particles into contact with the above-mentioned emulsion.

[0086] Preferably, the volume of the emulsion used in this step is greater than or equal to at least 80% of the total pore volume of the catalyst. More preferably, the volume of the emulsion used is 100% to 140% of the total pore volume of the catalyst, even more preferably 100% to 120% of the total pore volume of the catalyst. The pore volume of the catalyst is determined by nitrogen adsorption in a manner known per se. The pore volume measured by nitrogen adsorption is determined by the BJH (Barrett-Joyner-Halenda) model. The nitrogen adsorption-desorption isotherm according to the BJH model is described in the published text "The Journal of American Society" 73, 373, (1951) written by E.P. Barrett, L.G. Joyner and P.P. Halenda.

[0087] Generally, step (i) is carried out by impregnating the catalyst with an emulsion so that the emulsion penetrates into the pores of the catalyst. For this purpose, any known means can be used to make the liquid penetrate into the porous particles.

[0088] For example, it can be carried out by impregnating and stirring the catalyst in the emulsion.

[0089] Preferably, this step is carried out by agitating the catalyst particles and spraying the emulsion thereon.

[0090] This step can be carried out continuously or discontinuously, preferably continuously.

[0091] Within the process scope of the continuous mode, step (i) can be carried out, for example, in one of the following ways: - Spraying the emulsion on the catalyst in a mixing compartment located upstream of the vulcanization treatment device; - Spraying the emulsion on the catalyst in the feeding system of the vulcanization treatment device. For example, when the catalyst enters the vibrating feeder or the screw conveyor, mixing the emulsion with the catalyst and feeding it to the vulcanization treatment device are carried out jointly.

[0092] The duration of step (i) is variable, generally from several minutes to several hours. Preferably, the contact lasts for about 1 hour.

[0093] Step (i) can be carried out at a pressure from atmospheric pressure to 5 bar, preferably at atmospheric pressure, and the preferred temperature is from ambient temperature to 100 °C.

[0094] According to a preferred embodiment, step (i) is carried out in the temperature range of 25 °C to 100 °C, preferably 40 °C to 90 °C, more preferably 50 °C to 80 °C.

[0095] sulfiding treatment step (ii) The process according to the present invention further comprises at least one step (ii), during which the catalyst having the emulsion deposited thereon derived from step (i) is contacted with a sulfur-containing gas mixture comprising hydrogen and sulfide.

[0096] Advantageously, the sulfide is hydrogen sulfide (H2S), or a sulfide that may release hydrogen sulfide by hydrocracking under the operating conditions of this step. Such sulfides may be selected, for example, from elemental sulfur, CS2, organic sulfides (such as mercaptans, sulfides, disulfides, polysulfides, thiols, thiophenes, sulfoxides).

[0097] Preferably, the sulfide is hydrogen sulfide.

[0098] For example, it can be carried out in the manner described in patent application EP 1634939.

[0099] Therefore, according to a preferred embodiment of step (ii), the catalyst is contacted with a sulfur-containing gas mixture comprising hydrogen and hydrogen sulfide.

[0100] Advantageously, by volume, hydrogen sulfide accounts for 5% to 70% of the hydrogen sulfide + hydrogen mixture, preferably 10% to 60%.

[0101] In addition to hydrogen and sulfide, the sulfur-containing gas mixture may further comprise one or more other gases, such as an inert diluent gas (such as nitrogen). Such additional gas may, for example, account for 5% to 80% of the volume of the gas mixture.

[0102] Advantageously, step (ii) is carried out in a temperature range of 150 °C to 500 °C, preferably 200 °C to 350 °C.

[0103] Preferably, during the entire step (ii), the temperature is variable. Therefore, it can be carried out in at least two steps, a first step of gradually increasing the temperature, and then a second step of maintaining the temperature at 200 °C to 350 °C.

[0104] Preferably, step (ii) is carried out in a continuous mode in a sulfiding device comprising one or more reactors, and the catalyst is cyclically contacted with the sulfur-containing gas mixture in the reactor.

[0105] Step (ii) can be carried out in a fixed bed or a moving bed, for example, in a fluidized bed or a boiling bed, or in a rotary kiln. When using a moving bed, the sulfur-containing gas mixture can be circulated to the catalyst bed in a co-current or counter-current manner, preferably counter-current.

[0106] The amount of sulfur incorporated into the catalyst in this step depends on the amount of active metal present on the catalyst surface. Preferably, the amount of sulfur incorporated is 50% to 200% of the stoichiometric amount of sulfur required for all the active metal to be in the form of metal sulfide, preferably 80% to 120%, more preferably 90% to 110%.

[0107] For example, when the active metals of the catalyst are cobalt and molybdenum, the sulfide forms corresponding to 100% stoichiometric ratio can be assimilated into CoS and MoS2 respectively.

[0108] process According to the process of the present invention, step (ii) is carried out after step (i). Step (ii) can be carried out directly after step (i), or step (ii) can be separated by one or more intermediate steps (s).

[0109] Therefore, the process according to the present invention may further include a step of drying the catalyst between step (i) and step (ii), and this step can be carried out in a temperature range of 80 °C to 350 °C, preferably 100 °C to 200 °C, in the open air or in the presence of an inert gas such as a gaseous air stream, nitrogen, or any other suitable gas.

[0110] According to a preferred embodiment, the process does not include intermediate steps, especially does not include a drying step. In other words, step (ii) is carried out directly after step (i), and the catalyst on which the emulsion is deposited is directly sulfided.

[0111] The sulfiding treatment process according to the present invention may further include one or more additional steps that can be carried out before and / or after the above-mentioned step (i) and step (ii).

[0112] Therefore, a cooling step can be advantageously carried out after step (ii), during which the catalyst is cooled to the ambient temperature or a temperature close to the ambient temperature. This cooling, which is usually carried out step by step, can be carried out in the presence of a sulfur-containing gas mixture, or in the presence of any other suitable gas (such as hydrogen, an inert gas (such as nitrogen), oxygen, or a mixture of these gases), or in the presence of various gas mixtures used subsequently.

[0113] Therefore, a first stage of cooling the catalyst in a sulfur-containing gas mixture can be carried out, and then a second stage of cooling in an inert gas (such as nitrogen) can be carried out.

[0114] According to a preferred embodiment of the present invention, the process further includes a step of passivating the catalyst after step (ii), preferably oxidative passivation.

[0115] This oxidative passivation consists in bringing the catalyst into contact with oxygen or a sulfur-containing gas mixture. Preferably, a gas mixture containing less than 30% oxygen is used. This gas mixture can especially be air. The contact of the catalyst with the oxygen-containing gas can be carried out in multiple stages, and the oxygen content is gradually increased over time.

[0116] Preferably, this passivation treatment step is carried out at a temperature below or equal to 150 °C, and the duration is usually less than 24 hours. In particular, it can be carried out simultaneously with the step of cooling the catalyst at the end of step (ii).

[0117] When the sulfidation treatment process is carried out ex-situ, the advantage of the passivation treatment is especially to reduce the spontaneous combustion tendency of the sulfide phase present on the catalyst surface, so that it can be easily transferred or stored, for example, in metal drums or other types of containers.

[0118] The process according to the present invention can be carried out in-situ, that is to say, directly in the device using the catalyst.

[0119] According to a preferred embodiment, it is carried out ex-situ, that is to say, after the catalyst is removed from the device.

[0120] hydrotreating catalyst The process according to the present invention can sulfide any catalyst used for treating hydrocarbons in the refining and petrochemical fields.

[0121] These catalysts are in the form of porous solid particles, including at least one active metal, for example, especially a hydrogenation metal deposited on a support based on one or more refractory inorganic oxides.

[0122] The hydrogenation metal refers to the metals of Groups VIII and VIB of the periodic table.

[0123] Preferably, the catalyst treated by the process according to the present invention is a catalyst containing at least one Group VIII metal of the periodic table (such as cobalt, nickel, iron) and at least one Group VIB metal (such as molybdenum, tungsten, chromium). The weight content of the Group VIII metal generally accounts for 0.1% to 10% of the total weight of the catalyst, and the weight content of the Group VIB metal generally accounts for 1% to 20% of the total weight of the catalyst.

[0124] The hydrogenation metal is deposited on a support based on one or more refractory inorganic oxides, such as alumina, silica, silica-alumina, zeolite, zircon, oxides of titanium and boron, and mixtures of these oxides.

[0125] The process according to the present invention is more particularly suitable for sulfiding a hydrogenation catalyst containing an active metal deposited on a non-zeolite support, and the support is selected from alumina, silica, silica-alumina. More preferably, the non-zeolite support contains at least 30 wt% of alumina, and more preferably at least 50 wt%.

[0126] The process according to the present invention is particularly suitable for sulfiding a catalyst containing a metal association (CoMo, NiMo, NiW, NiCoMo) deposited on an alumina-based support.

[0127] In addition to the hydrogenated metal, the catalyst treated by the process according to the invention may include all suitable additional components. Thus, these catalysts may contain, for example (in a non-limiting manner), one or more halogens, boron, phosphides, one or more elements selected from groups IIIB, IVB, VB of the periodic table.

[0128] The process according to the invention is particularly suitable for sulfiding catalysts that do not contain any organic additives. Thus, it is particularly suitable for the sulfiding of catalysts in which the difference between the loss on ignition at 500 °C and the loss on ignition at 150 °C is less than or equal to 2 wt% relative to the weight of the initial catalyst.

[0129] In a manner well known to those skilled in the art, the expression "loss on ignition (LOI)" refers to the mass loss that occurs when the material is burned due to the departure of volatile materials.

[0130] Due to the decomposition of organic materials, the loss on ignition at 500 °C of catalysts containing these organic materials (such as organic additives) is particularly evident. Moreover, due to their high specific surface area and high hygroscopic properties, catalysts can adsorb a non-negligible amount of water from air humidity, and their loss on ignition at 150 °C may be between 5 wt% and 10 wt%. Therefore, in order to determine whether a catalyst contains organic additives, the difference between the loss on ignition at 500 °C and the loss on ignition at 150 °C should be considered.

[0131] Hydrocarbon treatment catalysts are usually in the form of small solid particles, such as beads, somewhat cylindrical particles, extrudates. The specific surface area measured by the BET method is usually between 100 m² / g and 300 m² / g, the pore volume determined by nitrogen adsorption is between 0.25 ml / g and 1 ml / g, and the average pore diameter determined by nitrogen adsorption is between 7 nm and 20 nm.

[0132] Once treated by the process according to the invention, the catalyst is ready for use and can advantageously be directly used in its intended hydrocarbon treatment process.

[0133] A second sulfiding treatment can also be carried out on the catalyst, especially in situ, immediately before using the catalyst. It may particularly involve sulfiding by passing a sulfur-containing liquid phase through the catalyst in the presence of hydrogen, and the sulfur-containing liquid phase is usually a sulfur-containing hydrocarbon fraction and / or rich in sulfur-containing hydrocarbons, such as a distillate to which dimethyl disulfide may be added.

[0134] Therefore, in order to precondition the catalyst and reduce the intensity and duration of the final sulfiding treatment carried out in situ, the process according to the invention can be used as a presulfiding treatment process, thereby saving time and increasing the efficiency of the hydrocarbon treatment process.

[0135] The catalyst obtained by the process according to the invention can be used in any industrial process using a sulfur-containing catalyst. These catalysts are particularly used in processes for treating hydrocarbons such as oil fractions, hydrocarbons from natural gas, and oxygen-containing or non-vegetable-based hydrocarbons.

[0136] Hydrocracking or hydroconversion, reforming, isomerization, alkylation, hydrogenation, dehydrogenation processes and so-called hydrotreating processes such as hydrodesulfurization, hydrodenitrogenation, hydrodearomatization, hydrodemetallization, hydrodeoxygenation processes, etc. can be cited.

[0137] The process according to the invention is particularly suitable for sulfiding catalysts used in oil fraction hydrotreating processes and hydrodesulfurization processes.

[0138] The process according to the invention is suitable for sulfiding both new catalysts and used catalysts that have been previously regenerated.

[0139] According to a preferred embodiment, the catalyst is a used catalyst that has been previously regenerated.

[0140] The used catalyst is a catalyst that has been used in a hydrotreating reactor and has become deactivated, especially due to the deposition of coke on its surface, that is, a mixture of heavy hydrocarbons, carbon residues, and metal impurities.

[0141] Regenerating a used catalyst is a well-known process that involves heating the catalyst to a high temperature in the presence of an oxygen-containing gas to burn off the coke.

[0142] process for treating used catalyst Therefore, another object of the present invention is a process for treating a used catalyst, comprising: - a step of heat-treating the catalyst in the presence of oxygen in a temperature range of 350 °C to 550 °C; and then - sulfiding the catalyst by the process as described above.

[0143] The heat-treatment step comprises heating the used catalyst to a temperature range of 350 °C to 550 °C in the presence of oxygen. The aim is to eliminate the coke on the surface of the catalyst by burning it.

[0144] Controlling the temperature inside the catalyst is particularly important during this step. The temperature must be high enough to burn the coke as completely as possible. However, it cannot exceed 550 °C (even locally), because effects that damage the catalyst will occur (such as by reducing the porosity of the catalyst).

[0145] Preferably, this heat treatment step is carried out at a temperature below or equal to 530 °C, preferably below or equal to 520 °C.

[0146] According to a preferred embodiment, the heat treatment step is carried out in whole or in part in the temperature range of 450 °C to 550 °C.

[0147] The temperature inside the catalyst can be controlled in a manner known per se, for example by appropriately placing thermocouples in the catalyst bed.

[0148] The first step is carried out in the presence of oxygen, for example by means of an oxygen-containing gas stream. For example, this gas may include air that is pure or mixed with additional oxygen or mixed with an inert gas in order to increase or decrease the oxygen content of the air. This gas may also include a mixture of oxygen and an inert gas (nitrogen), or other gas mixtures containing oxygen.

[0149] Preferably, the oxygen content of the gas is controlled in order to better control the combustion temperature. The oxygen content can be fixed or vary over time. The gas flow rate is also controlled in order to control the combustion.

[0150] This heat treatment step may include multiple stages carried out in the presence of different temperatures and / or varying amounts of oxygen.

[0151] Generally speaking, the total duration of this step depends on the amount of catalyst to be treated, the composition of the catalyst, the amount of coke on the catalyst surface, and the operating conditions (temperature, oxygen content). When the temperature is high, the duration is even shorter. It is usually between 0.1 and 20 hours, preferably between 0.2 and 10 hours.

[0152] The following examples are given purely for the purpose of illustrating the present invention. Detailed description

[0153] Examples The following examples are carried out on the following catalyst, which is derived from a hydrodeoxygenation unit and is a conventional used hydrotreating catalyst of the NiMo type on alumina. The catalyst is regenerated by heat treatment in the presence of an oxygen-containing gas in a rotary shutter device. This regenerated catalyst (referred to as catalyst C) contains 4% wt% of NiO and 18 wt% of MoO3 supported on γ-alumina. Its pore volume is 0.52 ml / g.

[0154] Comparative Example 1: A sample of 100 g of catalyst C is treated in the following manner: - Separate step (ii): Contact the catalyst with a gas mixture containing an H2S / H2 / N2 mixture having an H2S partial pressure of 0.3, an H2 partial pressure of 0.25, and an N2 partial pressure of 0.45. Conduct this step in a vertical reactor at ambient pressure, allowing the descending gas stream to pass through the catalyst bed at a gas hourly space velocity (GHSV) of 300 h -1 . Increase the temperature at a rate of 5 °C / min to 250 °C and then maintain it at this temperature for 2 hours.

[0155] Obtain the sulfided catalyst sample S1 in this way.

[0156] Comparative Example 2: Treat a 100 g sample of catalyst C in the following manner: - First step (i): Contact the catalyst with an organic solution by impregnating the catalyst in the organic solution at a temperature of 60 °C for 1 hour. The organic solution contains 14.3 g of rapeseed oil (corresponding to 30% of the catalyst pore volume), and then - Second step (ii): Consistent with Example 1 above.

[0157] Obtain the sulfided catalyst sample S2 in this way.

[0158] Comparative Example 3: Treat a 100 g sample of catalyst C in the following manner: - First step (i): Contact the catalyst with the solution by impregnating the catalyst in 30 ml of an aqueous citric acid solution at a temperature of 60 °C for 1 hour. The aqueous citric acid solution has an acid concentration of 27 wt% (corresponding to 60% of the catalyst pore volume), and then - Second step (ii): Consistent with Example 1 above.

[0159] Obtain the sulfided catalyst sample S3 in this way.

[0160] Comparative Example 4: Treat a 100 g sample of catalyst C in the following manner: - First step (i): Contact the catalyst with the solution by impregnating the catalyst in 30 ml of an aqueous citric acid solution at a temperature of 60 °C for 1 hour. The aqueous citric acid solution has an acid concentration of 27 wt% (corresponding to 60% of the catalyst pore volume), and then - Step (i): The catalyst is brought into contact with an organic solution by impregnating the catalyst in the organic solution at a temperature of 60 °C for 1 hour. The organic solution contains 14.3 g of rapeseed oil, 4.7 g of di-tert-butyl polysulfide, and 0.19 g of a surfactant comprising polyethylene glycol trimethylnonyl ether (trade name: Tergitol TMX 100X®) (corresponding to 40% of the catalyst pore volume), and then - Step (ii): Consistent with Example 1 above.

[0161] Thereby, a sulfided catalyst sample S4 is obtained.

[0162] Example 5 according to the present invention: A 100 g sample of catalyst C is treated as follows: - Step (i): The catalyst is brought into contact with an emulsion by impregnating the catalyst in the emulsion at a temperature of 60 °C for 1 hour. The emulsion includes an aqueous phase and an organic phase. The aqueous phase contains 30 ml of an aqueous citric acid solution with an acid concentration of 27 wt% (corresponding to 60% of the catalyst pore volume), and the organic phase contains 19 g of rapeseed oil and 0.19 g of a non-ionic surfactant comprising polyethylene glycol trimethylnonyl ether (trade name: Tergitol TMX 100X®) (corresponding to 40% of the catalyst pore volume), and then - Step (ii): Consistent with Example 1 above.

[0163] Thereby, a sulfided catalyst sample S5 is obtained.

[0164] Example 6 according to the present invention: A 100 g sample of catalyst C is treated as follows: - Step (i): The catalyst is brought into contact with an emulsion by impregnating the catalyst in the emulsion at a temperature of 60 °C for 1 hour. The emulsion includes an aqueous phase and an organic phase. The aqueous phase contains 30 ml of an aqueous citric acid solution with an acid concentration of 27 wt% (corresponding to 60% of the catalyst pore volume), and the organic phase contains 14.3 g of rapeseed oil, 4.7 g of di-tert-butyl polysulfide, and 0.19 g of a non-ionic surfactant comprising polyethylene glycol trimethylnonyl ether (trade name: Tergitol TMX 100X®) (corresponding to 40% of the catalyst pore volume), and then - Step (ii): Consistent with Example 1 above.

[0165] Thereby, a sulfided catalyst sample S6 is obtained.

[0166] Example 7 according to the present invention: A sample of 100 g of catalyst C was treated as follows: - Step (i): The catalyst was contacted with an emulsion by impregnating the catalyst in the emulsion at a temperature of 60 °C for 1 hour. The emulsion included an aqueous phase and an organic phase. The aqueous phase contained 30 ml of maleic acid aqueous solution with an acid concentration of 44 wt% (corresponding to 60% of the catalyst pore volume), and the organic phase contained 14.3 g of rapeseed oil, 4.7 g of di-tert-butyl polysulfide, and 0.19 g of a non-ionic surfactant containing polyethylene glycol trimethyl nonyl ether (trade name: Tergitol TMX 100X®) (corresponding to 40% of the catalyst pore volume). Then - Step (ii): It was the same as Example 1 above.

[0167] Thereby, a sulfided catalyst S7 sample was obtained.

[0168] Example 8 according to the present invention: A sample of 100 g of catalyst C was treated as follows: - Step (i): The catalyst was contacted with an emulsion by quickly impregnating the catalyst in the emulsion at a temperature of 60 °C (contact time less than 5 minutes). The emulsion included an aqueous phase and an organic phase. The aqueous phase contained 30 ml of citric acid aqueous solution with an acid concentration of 27 wt% (corresponding to 60% of the catalyst pore volume), and the organic phase contained 14.6 g of rapeseed oil and 4.7 g of di-tert-butyl polysulfide (corresponding to 40% of the catalyst pore volume). Then - Step (ii): It was the same as Example 1 above.

[0169] Thereby, a sulfided catalyst S8 sample was obtained.

[0170] Example 9 according to the present invention: A sample of 100 g of catalyst C was treated as follows: - Step (i): The catalyst was contacted with an emulsion by impregnating the catalyst in the emulsion at a temperature of 60 °C for 1 hour. The emulsion included an aqueous phase and an organic phase. The aqueous phase contained 30 ml of phosphoric acid aqueous solution with an acid concentration of 15 wt% (corresponding to 60% of the catalyst pore volume), and the organic phase contained 14.3 g of rapeseed oil, 4.7 g of di-tert-butyl polysulfide, and 0.19 g of a non-ionic surfactant containing polyethylene glycol trimethyl nonyl ether (trade name: Tergitol TMX 100X®) (corresponding to 40% of the catalyst pore volume). Then - Step (ii): It was the same as Example 1 above.

[0171] The sulfided catalyst sample S9 was thus obtained.

[0172] Example 10 : Performance evaluation of sulfided catalysts S1 to S9 For catalysts S1 to S9, the following properties were evaluated: - determine the sulfidation rate of the catalyst : The sulfur content was measured by an organic elemental analyzer capable of determining the contents of C, H, N, O, and S. The sulfidation rate (ST1) was defined as the ratio of the sulfur content of the catalyst measured on the dry matrix after correcting for the loss on ignition at 500 °C to the theoretical sulfur content (ST0) of the catalyst, where the theoretical sulfur content (ST0) of the catalyst corresponded to the stoichiometric amount of sulfided metal (i.e., in the form of sulfides MoS2 and NiS). The sulfidation rate was determined by the following equation:

[0173] - determine the loss of the catalyst : This parameter in a 50 g catalyst sample was determined according to the rules disclosed in standard ASTM D - 4058, where the catalyst sample was placed in a cylindrical barrel with a lifter (a metal plate welded to the inner wall of the barrel) on its bushing, and then after closing the barrel with a lid, the assembly was rotated for 30 minutes, and then the weight loss of the catalyst sample was measured by sieving on a No. 20 sieve (0.85 mm) to eliminate the fines generated. Then the weight percentage of the fines generated was calculated.

[0174] This test can simulate the continuous falling of catalyst particles (which causes breakage and fines).

[0175] - determine the hydrodesulphurisation (HDS) activity : This test was carried out in a guiding device by subjecting a feedstock containing diesel obtained by direct distillation of crude oil (referred to as "straight-run product") to hydrodesulfurization treatment, where the sulfur content of the feedstock was 1.514 wt%. The operating conditions were as follows: pressure 5 MPa (50 bar), the ratio of H2 / feedstock was 300, and the gas hourly space velocity (GHSV) was 1.5 h -1 , and the temperature was 360 °C.

[0176] The sulfur content of the feedstock leaving the device was measured by a UV fluorescence analyzer.

[0177] The apparent constant of the desulfurization reaction was calculated according to the following equation E1:

[0178] where, K v = apparent reaction constant α = reaction order (assumed to be 1.2) S0 = sulfur content of the feed HSV = hourly space velocity of the liquid feed.

[0179] The performance of each sample was evaluated relative to a reference catalyst. For this purpose, the Relative Volume Activity (RVA) was calculated according to Equation E2 below:

[0180] For reference, the K v value assigned to the corresponding new catalyst was 100, and this catalyst was activated in situ (in the unit) by a mixture of diesel and dimethyl disulfide.

[0181] - determine the hydrodeoxygenation (HDO) activity : This test was carried out in a pilot plant by hydrodeoxygenating a feed containing rapeseed oil. The operating conditions were as follows: pressure 2 MPa (20 bar), H2 / feed ratio of 16000, gas hourly space velocity (GHSV) of 0.5 h -1 , and temperature of 295 °C.

[0182] The oxygen content of the feed entering and leaving the unit was measured.

[0183] The apparent constant of the deoxygenation reaction was calculated according to Equation E1' below:

[0184] where K v = apparent reaction constant α = reaction order (assumed to be 1.4) O = oxygen content of the effluent O0 = oxygen content of the feed HSV = hourly space velocity of the liquid feed.

[0185] The performance of each sample was evaluated relative to a reference catalyst. For this purpose, the Relative Volume Activity (RVA) was calculated according to Equation E2' below:

[0186] For reference, the K v value assigned to the corresponding new catalyst was 100, and this catalyst was activated in situ (in the unit) by a mixture of hydrotreated vegetable oil and dimethyl disulfide.

[0187] Details of the results obtained are given in Table 1 below.

[0188] [Table 1]

[0189] These results show that the properties of catalyst samples S5, S6, S7, S8, and S9 vulcanized according to the process of the present invention are superior to those of samples S1, S2, S3, and S4 not vulcanized according to the process of the present invention.

[0190] These results indicate that the process according to the present invention enables the catalyst to have superior properties in terms of vulcanization rate, loss reduction, and activity in various hydrotreating reactions.

Claims

1. A process for sulfiding a hydrocarbon processing catalyst, comprising: (i) at least one step of contacting the catalyst with an emulsion comprising: (ia) an aqueous phase comprising at least one acid; and (ib) an organic phase; then (ii) at least one step of contacting the catalyst with a sulphur-containing gas mixture comprising hydrogen and sulphide.

2. The process according to claim 1, characterized in that The aqueous phase (ia) comprises one or more acids in free acid form or in salified form, the acid being selected from inorganic acids and organic acids, preferably from carboxylic organic acids, more preferably from monocarboxylic acids, dicarboxylic acids, tricarboxylic acids, aminopolycarboxylic acids and mixtures thereof.

3. A process according to any one of the preceding claims, characterised in that The carboxylic acid is selected from maleic acid, glycolic acid, thioglycolic acid, citric acid and mixtures thereof, more preferably the aqueous phase contains citric acid.

4. A process according to any one of the preceding claims, characterised in that The acid accounts for 3 wt % to 30 wt %, preferably 5 wt % to 20 wt % of the total weight of the emulsion, and the content is expressed based on the free acid form.

5. A process according to any one of the preceding claims, characterised in that By volume, the aqueous phase (ia) accounts for 40%-70%, preferably 50%-60% of the total volume of the emulsion.

6. A process according to any one of the preceding claims, characterised in that The organic phase (ib) comprises one or more oils, preferably chosen from compounds or mixtures of compounds comprising at least one chain having at least 8 carbon atoms, more preferably chosen from vegetable oils, animal oils, mineral oils, synthetic oils and mixtures thereof.

7. A process according to any one of the preceding claims, characterised in that The organic phase (ib) comprises one or more mineral oils, preferably selected from fuels such as gasoline, jet oil, naphtha, diesel and / or combustible fractions, fuel oil fractions, lubricating oil fractions, solvent fractions.

8. The process according to claim 6 or 7, characterized in that The organic phase (ib) comprises one or more vegetable oils, preferably selected from castor oil, sunflower oil, peanut oil, soybean oil, rapeseed oil, coconut oil, corn oil, palm oil, linseed oil and safflower oil.

9. A process according to any one of the preceding claims, characterised in that The organic phase (ib) further comprises one or more sulfides, preferably selected from organic sulfides, more preferably selected from polysulfides, thiols, sulfoxides and mixtures of these compounds, and more preferably selected from: - Polysulfide is selected from the group consisting of: n -R', wherein: n is an integer ranging from 3 to 20, preferably from 3 to 8, more preferably from 3 to 7, and R and R' are identical or different and represent an organic group containing 1 to 150 carbon atoms, preferably 10 to 60 carbon atoms, more preferably 15 to 30 carbon atoms; R' may also represent hydrogen; these groups may be saturated or unsaturated, linear or branched or cyclic, and may be selected from the group consisting of alkyl, alkenyl, aryl, alkaryl and aralkyl groups, which groups may include at least one heteroatom; - thiols are chosen from compounds of formula R-SH, in which R represents an organic group containing from 1 to 150 carbon atoms, preferably from 10 to 60 carbon atoms, more preferably from 8 to 30 carbon atoms; this group may be saturated or unsaturated, linear or branched or cyclic, and may be chosen from the group consisting of alkyl, alkenyl, aryl, alkaryl and aralkyl groups, which groups may include at least one heteroatom; - sulfoxide is chosen from compounds of formula R-SO-R', wherein R and R' are identical or different and represent an organic group containing 1 to 150 carbon atoms, preferably 10 to 60 carbon atoms, more preferably 15 to 30 carbon atoms; R' may also represent hydrogen; these groups may be saturated or unsaturated, linear or branched or cyclic and may be chosen from the group consisting of alkyl, alkenyl, aryl, alkaryl and aralkyl groups, which groups may include at least one heteroatom; - and mixtures of these compounds.

10. A process according to any one of the preceding claims, characterised in that The aqueous phase (ia) further comprises one or more sulfides, preferably selected from inorganic sulfides, more preferably selected from thiosulfates such as sodium thiosulfate, potassium thiosulfate, ammonium thiosulfate, metabisulfites such as sodium metabisulfite, potassium metabisulfite, ammonium metabisulfite, and elemental sulfur.

11. A process according to any one of the preceding claims, characterised in that The emulsion further comprises one or more surfactants, preferably selected from anionic surfactants, nonionic surfactants, amphoteric surfactants and mixtures thereof, more preferably selected from nonionic surfactants.

12. A process according to any one of the preceding claims, characterised in that The emulsion includes one or more nonionic surfactants selected from: -Alkoxylated alkyl (C8-C 24 ) phenols; - saturated or unsaturated, linear or branched, alkoxylated or glycerolated C8 to C 40 Alcohols, and contain one or two fatty chains; - saturated or unsaturated, linear or branched C8 to C 30 Acid esters, and polyol or polyethylene glycol esters; - saturated or unsaturated, linear or branched C8 to C 30 Esters of acids and esters of sorbitol, preferably oxyethylated; - Fatty acid and sucrose esters; -alkyl (C8-C 30 ) polyglycosides and alkenyl (C8-C 30 ) polyglycosides, possibly alkoxylated (0 to 10 oxyalkylene units) and containing 1 to 15 glucose units; alkyl (C8-C 30 ) Polyglycoside esters; - saturated or unsaturated, oxyethylated vegetable oils; - ethylene oxide and / or propylene oxide condensate; - and mixtures thereof; and preferably selected from C8 to C6 containing 1 to 40 mol of ethylene oxide 24 Oxyethylated alcohols, preferably 2 to 20 moles of ethylene oxide.

13. The process according to claim 11 or 12, characterized in that ,, the total content of the surfactant accounts for 0.1wt%-5wt% of the total weight of the emulsion, preferably 0.2wt%-2.5wt%, more preferably 0.5wt% to 1.5wt%.

14. A process according to any one of the preceding claims, characterised in that The volume of the emulsion used in step (i) is greater than or equal to at least 80% of the total pore volume of the catalyst, preferably from 100% to 140% of the total pore volume of the catalyst, more preferably from 100% to 120% of the total pore volume of the catalyst.

15. A process according to any one of the preceding claims, characterised in that Step (i) is carried out at a temperature ranging from 25°C to 100°C, preferably from 40°C to 90°C, more preferably from 50°C to 80°C.

16. A process according to any one of the preceding claims, characterised in that Step (ii) is performed by contacting the catalyst with a sulphur-containing gas mixture comprising hydrogen and hydrogen sulphide.

17. A process for treating a used catalyst, characterized in that: include: - a step of thermally treating the catalyst in the presence of oxygen at a temperature ranging from 350° C. to 550° C.; Then - Sulphiding the catalyst by a process as claimed in any one of the preceding claims.

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