FR3121368A1 - Process for sulfurizing a hydrotreating and/or hydrocracking catalyst containing an organic compound by hydrothermal synthesis - Google Patents

Abstract

Process for the sulfurization of a catalyst comprising a porous support, a group VIB element and/or a group VIII element, and at least one organic compound, said process comprising the following steps:a) a presulfurization step comprising:a1) a dry impregnation step at a temperature below 50°C by bringing said catalyst into contact with an impregnation solution comprising a sulfurizing agent, a2) a drying step to form a presulfided catalyst, b) then a step of sulfurization comprising: b1) a step of impregnating in excess at a temperature between 50 and less than 200°C said presulfided catalyst by bringing said catalyst into contact with an acid impregnation solution comprising a sulfurizing agent,b2) a step of drying of the catalyst obtained in step b1).

Description

Process for sulfurizing a hydrotreating and/or hydrocracking catalyst containing an organic compound by hydrothermal synthesis

Field of invention

The invention relates to a method for sulfurizing hydrotreating and/or hydrocracking catalysts containing an organic compound.

The invention also relates to catalysts sulfurized by said sulfurization process.

The invention also relates to the use of the catalyst obtained by said sulfurization process for hydrotreating and/or hydrocracking.

State of the art

Usually, a catalyst for the hydrotreatment of hydrocarbon cuts is intended to eliminate the sulphur, nitrogen or aromatic compounds contained therein or in order, for example, to bring a petroleum product to the required specifications (sulphur content, aromatic content, etc. ..) for a given application (automotive fuel, petrol or diesel, heating oil, jet fuel).

Conventional hydrotreating catalysts generally comprise an oxide support and an active phase based on metals from groups VIB and VIII in their oxide forms as well as phosphorus.

The preparation of these catalysts generally comprises a stage of impregnation of the support using an impregnation solution containing metals and phosphorus on the support, followed by drying and possibly calcination making it possible to obtain the active phase in their oxide forms.

The addition of an organic compound to the hydrotreating catalysts to improve their activity has been recommended by those skilled in the art, in particular for catalysts which have been prepared by impregnation followed by drying without subsequent calcination. These catalysts are often referred to as "additive dried catalysts". The introduction of the organic compound makes it possible to increase the dispersion of the active phase, thus leading to a more active catalyst.

The metals of these catalysts, with or without additives, are only active for hydrotreating and/or hydrocracking reactions in the sulphide form. It is therefore necessary to operate a sulfurization of the catalyst prior to its implementation.

Conventional sulfurization processes are carried out in the hydrotreating unit itself (we then speak of in situ sulfurization) or prior to loading the catalyst into the unit (we then speak of ex situ sulfurization).

In-situ sulfurization with addition of sulfurizing agent is widely practiced in industry today. In-situ sulfurization is carried out on the catalyst loaded into the reactor by injecting a sulfur compound in sufficient quantity to allow the transformation of the metal oxides of the catalyst into sulphides in a reducing medium. This sulfur agent is generally of the mercaptan, sulphide, disulphide or polysulphide type, in certain cases it is directly hydrogen sulphide (H ₂ S). Most often DMDS (dimethyl disulphide), DMS (dimethyl sulphide), or TBPS (tert-butyl polysulphide), are used, added to a hydrocarbon feedstock. The quantity of sulfur injected is generally greater than the stoichiometry necessary to transform the oxides into sulphides.

All conventional industrial sulfurization processes, whether in situ or ex situ, have the disadvantage of having to be carried out at a high temperature, generally above 250°C and often around 300 to 350°C.

Moreover, even by injecting a quantity of sulfur greater than stoichiometry, the metals are not always completely sulphurized during conventional sulphidation processes. A problem posed to those skilled in the art is thus to obtain very well sulfurized catalysts in order to maximize their catalytic performance in terms of activity. The sulfur character is evaluated by the sulfurization rate defined as the ratio between the experimental S/(metals) and theoretical S/(metals) molar ratios, multiplied by 100; the theoretical ratio corresponding to the total transformation of metal oxides into sulphides. A catalyst is considered to be well sulfurized when its degree of sulfurization is greater than or equal to 90%, preferably greater than 95% and even more preferably greater than 97%. Conventional sulfurization processes generally achieve a sulfurization rate of around 70-80%.

A completely different route to sulfurization is the so-called hydrothermal sulfurization process, which makes it possible to prepare sulfurized catalysts at a much lower temperature and to obtain an improved rate of sulfurization compared to conventional sulfurization processes. This sulfurization process is particularly well described in the publications "A Study on the origin of the active sites of HDN catalysts using alumina-supported MoS ₃ nanoparticles as a precursor", Wei Han, Hong Nie, Xiangyun Long, Mingfeng Li, Qinghe Yang , Dadong Li, Catal.Sci.Technol., 2016, 6, 3497-3509 and “Preparation of hydrodesulfuratization catalysts using MoS ₃ nanoparticles as a precursor”, Yang Gao, Wei Han, Xiangyun Long, Hong Nie, Dadong Li, Applied Catalysis B: Environmental 224 (2018) 330-340.

The catalysts described in these publications are prepared by deposit-precipitation of an acidic aqueous solution containing molybdenum in the form of Na ₂ MoO ₄ x 2 H ₂ O and thioacetamide on a support at a temperature of 84°C followed by a drying. Thioacetamide, a sulfur compound with the formula CH ₃ C(S)NH ₂ , hydrolyses in the acid solution and forms H ₂ S in situ. This step makes it possible to form a catalyst precursor comprising MoS ₃ nanoparticles deposited on the support. The active form MoS ₂ is then formed from the catalyst precursor by activation (heat treatment) at 360° C. or 500° C. respectively in the presence of nitrogen or hydrogen, in the presence or absence of H ₂ S. Nickel can be added by conventional impregnation in a separate step just before or after the heat activation step. The authors observe an increase in the catalytic activity in hydrotreating compared to a catalyst prepared conventionally via the oxide form.

Although this method makes it possible to prepare sulphide catalysts showing an increase in catalytic activity in hydrotreating, a loss of active phase is observed during the preparation. Indeed, a significant part of the molybdenum present in the acid solution is lost because it is not introduced on the support. This method also has the disadvantage of requiring an additional step for the introduction of a group VIII element which must be carried out after the hydrothermal sulphidation.

Objects of the invention

In this context, one of the objectives of the present invention is to improve the so-called hydrothermal sulphidation process making it possible to improve the catalytic activity in hydrotreating and/or hydrocracking.

This goal is achieved through presulphurization (step a) carried out by dry impregnation of a sulphurizing agent and at low temperature (preferably at room temperature) followed by drying. The presulphurization stage is carried out before the sulphurisation stage (stage b), the latter being carried out by impregnation in excess of a sulphurizing agent in an acid medium and “hot”, that is to say at a temperature higher than the impregnation temperature of step a) of presulphurization and in particular at a temperature of between 50 and less than 200° C., followed by drying.

More particularly, the present invention relates to a process for sulfurizing a catalyst comprising a porous support, at least one element from group VIB and/or at least one element from group VIII, and at least one organic compound, said process comprising the steps following:

a) a presulphurization stage comprising:

a1) a dry impregnation step at a temperature below 50°C of said catalyst, in which said catalyst is brought into contact with an impregnation solution comprising a sulfurizing agent,

a2) a drying step at a temperature below 200°C of the catalyst obtained in step a1) to form a presulphurized catalyst,

b) then a sulfurization step comprising:

b1) an excess impregnation step at a temperature of between 50 and less than 200°C of said presulfided catalyst, in which said catalyst is brought into contact with an acid impregnation solution comprising a sulfurizing agent,

b2) a step of drying at a temperature below 200° C. the catalyst obtained in step b1) to form a sulfur catalyst.

The introduction of a presulphurization step (step a) makes it possible to observe several advantages compared to the hydrothermal sulphidation process without a presulphurization step.

The applicant has in fact observed, surprisingly, that the introduction of a presulphurization stage before a so-called hydrothermal sulphurisation stage makes it possible to observe a synergistic effect at the level of the activity in hydrotreating and hydrocracking.

Without wishing to be bound by any theory, the combination of a presulphurization step carried out by dry impregnation at low temperature with a sulphurization step by excess impregnation in an acidic and hot medium, makes it possible to improve the sulphurization of metals and to favor the promotion of the sulphide sheets of the metal of group VIB by the metal of group VIII, which is favorable to the hydrotreating reactions.

In addition, another important advantage is the fact that, thanks to the presulphurization step, no or very little loss of group VIII and/or VIB metals conventionally observed during step b), and in particular during of the step of impregnation in acid solution (step b1). This allows on the one hand to keep the active phase (and to avoid any loss of metal during the preparation) and on the other hand to be able to introduce a group VIII metal before steps a) and b) without adding d specific step of introducing a Group VIII metal.

Alternatively, the amount of sulfurizing agent added to the impregnation solution of step a1) is such that the molar ratio S/(group VIB and/or group VIII elements) is between 0.1 and 10.

According to a variant, step a1) is carried out at ambient temperature.

According to a variant, the solvent of the impregnation solution of step a1) is chosen from water or ethanol or a mixture of ethanol and water.

According to a variant, the sulfurizing agent of steps a1) and b1) is chosen from thioacetamide, thioacetic acid and thiourea.

According to a variant, the total quantity of sulfurizing agent added to the impregnation solution b1) is such that the ratio S/(group VIB and/or group VIII elements) is between 1 and 200.

According to a variant, the acid of the acid impregnation solution of step b1) is chosen from hydrochloric acid, sulfuric acid, sulfamic acid, formic acid, lactic acid and γ-ketovaleric acid.

According to a variant, the solvent of the impregnation solution of step b1) is chosen from chosen from 2-(2-methoxyethoxy)ethanol, 2-(2-ethoxyethoxy)ethanol, 2-(2-butoxyethoxy )ethanol, 2-(2-hexyloxyethoxy)ethanol, triethylene glycol methyl ether, triethylene glycol ethyl ether, dipropylene glycol n-butyl ether, tripropylene glycol methyl ether, tripropylene glycol n-butyl ether and water, taken alone or in blend.

According to a variant, the method according to the invention further comprises an activation step c) in which said sulfur catalyst obtained in step b) is brought into contact with an inert gas stream at a temperature between 200 and 450° C or with a reducing gas flow at a temperature between 50 and 450°C.

According to this variant, the activation step c) is carried out without addition of sulfurizing agent.

Alternatively, the group VIB element content is between 5 and 40% by weight expressed as group VIB metal oxide relative to the total weight of the catalyst and the group VIII element content is between 1 and 10% by weight. expressed as group VIII metal oxide relative to the total weight of the catalyst.

According to a variant, the element from group VIB is chosen from molybdenum and tungsten, and the element from group VIII is chosen from cobalt and nickel.

According to a variant, the organic compound is chosen from an organic compound containing oxygen and/or nitrogen and/or sulfur.

According to a variant, the organic compound is chosen from a compound comprising one or more chemical functions chosen from a carboxylic, alcohol, thiol, thioether, sulphone, sulphoxide, ether, aldehyde, ketone, ester, carbonate, amine, nitrile, imide, oxime, urea, amide, or a compound including a furan ring or even a sugar.

According to a variant, the organic compound is chosen from γ-valerolactone, 2-acetylbutyrolactone, triethylene glycol, diethylene glycol, ethylene glycol, ethylenediaminetetraacetic acid (EDTA), maleic acid, malonic acid, citric acid, acetic acid, oxalic acid, malic acid, gluconic acid, glucose, fructose, sucrose, sorbitol, xylitol, γ-ketovaleric acid, a succinate of dialkyl C1-C4 and more particularly dimethyl succinate, dimethylformamide, 1-methyl-2-pyrrolidinone, propylene carbonate, 2-methoxyethyl 3-oxobutanoate, bicine, tricine, 2-furaldehyde (also known as furfural), 5-hydroxymethylfurfural, 2-acetylfuran, 5-methyl-2-furaldehyde, ascorbic acid, butyl lactate, ethyl lactate, butyl butyryllactate, 3- ethyl hydroxybutanoate, ethyl 3-ethoxypropanoate, 2-ethoxyethyl acetate, 2-butoxyethyl acetate, acryla te of 2-hydroxyethyl, 1-vinyl-2-pyrrolidinone, 1,3-dimethyl-2-imidazolidinone, 1,5-pentanediol, 1-(2-hydroxyethyl)-2-pyrrolidinone, 1-(2 -hydroxyethyl)-2,5-pyrrolidinedione, 5-methyl-2(3H)-furanone, 1-methyl-2-piperidinone, 4-aminobutanoic acid, butyl glycolate, ethyl 2-mercaptopropanoate , ethyl 4-oxopentanoate, diethyl maleate, dimethyl maleate, dimethyl fumarate, diethyl fumarate, dimethyl adipate and dimethyl 3-oxoglutarate, diethyl tartrate and dimethyl malate diethyl.

According to one variant, the catalyst also comprises phosphorus, the phosphorus content being between 0.1 and 20% by weight, expressed as P ₂ O ₅ relative to the total weight of the catalyst.

According to a variant, the porous support is a support based on alumina or silica or silica-alumina.

The invention also relates to catalysts sulfurized by said sulfurization process.

The invention also relates to the use of the catalyst obtained by said sulfurization process in a process for the hydrotreating and/or hydrocracking of hydrocarbon cuts.

In the following, the groups of chemical elements are given according to the CAS classification (CRC Handbook of Chemistry and Physics, publisher CRC press, editor-in-chief DR Lide, ^81st edition, 2000-2001). For example, group VIII according to the CAS classification corresponds to the metals of columns 8, 9 and 10 according to the new IUPAC classification.

By hydrotreating we mean reactions including in particular hydrodesulphurization (HDS), hydrodenitrogenation (HDN) and the hydrogenation of aromatics (HDA).

Description of the invention

Sulphidation process

The invention relates to a method for sulfurizing a catalyst comprising a porous support, at least one element from group VIB and/or at least one element from group VIII, and at least one organic compound, said method comprising the following steps:

a) a presulphurization stage comprising:

a1) a dry impregnation step at a temperature below 50°C of said catalyst, in which said catalyst is brought into contact with an impregnation solution comprising a sulfurizing agent,

a2) a drying step at a temperature below 200°C of the catalyst obtained in step a1) to form a presulphurized catalyst,

b) then a sulfurization step comprising:

b1) an excess impregnation step at a temperature of between 50 and less than 200°C of said presulfided catalyst, in which said catalyst is brought into contact with an acid impregnation solution comprising a sulfurizing agent,

b2) a step of drying at a temperature below 200° C. the catalyst obtained in step b1) to form a sulfur catalyst.

The different steps of the sulfurization process according to the invention are described in detail below.

Step a) presulphurization

Step a1) of dry impregnation at a temperature below 50°C

According to step a1) of the sulfurization process according to the invention, a dry impregnation step is carried out at a temperature below 50° C. of a catalyst comprising a porous support, at least one element from group VIB and/ or at least one element from group VIII, at least one organic compound, and optionally phosphorus, in which said catalyst is brought into contact with an impregnation solution comprising a sulfurizing agent.

Said catalyst can be a fresh or rejuvenated catalyst requiring activation or re-activation by sulfurization. This catalyst can be obtained by any method known to those skilled in the art.

The impregnation step a1) is carried out by one or more dry impregnations, and, preferably, by a single dry impregnation of said catalyst.

Dry impregnation consists of introducing a volume of impregnation solution less than or equal to the pore volume of the catalyst. Dry impregnation allows all of the sulfurizing agent contained in the impregnation solution to be deposited on a given catalyst.

The impregnation step a1) is carried out at a temperature below 50°C, preferably at a temperature between 5 and 45°C, preferably between 10 and 30°C. Particularly preferably, the impregnation step a1) is carried out at room temperature. The temperature is chosen low enough to avoid the decomposition of the sulfurizing agent.

The impregnation solution includes a sulfurizing agent. The sulfurizing agent is a compound containing at least one sulfur atom. The sulfurizing agent comprises in particular a C=S function which decomposes during the following drying step a2) in the absence of hydrogen. The sulfurizing agent can preferably be chosen from thioacetamide, thioacetic acid, thiourea, 1,3-dimethylthiourea, 1,3-diethylthiourea, 1,1,3,3-tetramethylthiourea, 2-thiouracil , rhodanine, bis(dimethylthiocarbamyl) disulfide, O,O'-diisopropyldithiobis(thioformate) and thiosemicarbazide. Preferably, the sulfurizing agent is thioacetamide, thioacetic acid or thiourea. Even more preferably, the sulfurizing agent is thioacetamide.

The amount of sulfurizing agent added to the impregnation solution is preferably such that the molar ratio S/(group VIB and/or group VIII elements) is greater than or equal to 0.1, preferably between 0, 1 and 10 and more preferably between 0.25 and 5.

The impregnation solution may comprise any polar solvent known to those skilled in the art. Indeed, a polar solvent makes it possible to dissolve the sulfurizing agent in a minimum volume (dry impregnation). A list of the usual polar solvents as well as their dielectric constant can be found in the book “Solvents and Solvent Effects in Organic Chemistry”, C. Reichardt, Wiley-VCH, 3rd edition, 2003, pages 472-474. Said polar solvent used is advantageously chosen from a compound comprising one or more chemical functions chosen from an alcohol, sulphone, sulphoxide, ether, aldehyde, ketone, ester, carbonate, nitrile, amide function and water, taken alone or as a mixture. Said polar solvent can also advantageously be chosen from the group formed by methanol, ethanol, isopropanol, butanol-1, pentanol-1, 1,5-pentanediol, 1,6-hexanediol, water, phenol, cyclohexanol, a glycol, ethylene glycol, diethylene glycol, triethylene glycol, a polyethylene glycol (with a molecular weight between 200 and 1500 g/mol), propylene glycol, a glycol ether, 1-methoxy -2-propanol, 1-butoxy-2-propanol, 2-butoxyethanol, 2-(2-butoxyethoxy)ethanol, 2-(2-methoxyethoxy)ethanol, 2-(2-ethoxyethoxy)ethanol, 2-(2-butoxyethoxy)ethanol, 2-(2-hexyloxyethoxy)ethanol, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, triethylene glycol dimethyl ether, triethylene glycol methyl ether, triethylene glycol ethyl ether, triethylene glycol butyl ether, dipropylene glycol methyl ether, dipropylene glycol ethyl ether, dipropylene glycol n-propyl ether, dipropylene glycol n-butyl ether , tripropylene glycol methyl ether, tripropylene glycol n-butyl ether, a glycol acetate, glycerol, dioxane, propylene carbonate, ethyl acetate, DMSO (dimethyl sulfoxide), N-methylpyrrolidone (NMP) and sulfolane, taken alone or as a mixture. The solvent may contain water. Very preferably, the solvent used is water or ethanol or a mixture of ethanol and water. In a variant, the sulfurizing agent is introduced without solvent if it is liquid in the impregnation condition.

According to a variant of the invention, the impregnation solution can also comprise an acid. The nature and quantity of the acid are those described in step b1). The acid can be the same as or different from the acid in step b1).

Advantageously, after each impregnation step, the impregnated support is allowed to mature. The maturation allows the impregnation solution to diffuse homogeneously within the porosity of the catalyst.

Any maturation step described in the present invention is advantageously carried out at atmospheric pressure, in an atmosphere saturated with solvent and at a temperature between 17° C. and 50° C., and preferably at room temperature. Generally, a maturation period of between ten minutes and forty-eight hours, and preferably between thirty minutes and five hours, is sufficient. Longer durations are not excluded, but do not necessarily bring improvement.

When several impregnation steps are carried out, each impregnation step is preferably followed by an intermediate drying step such as the drying step a2) described below.

Stage a2 ): Drying

According to step a2) of the sulfurization process according to the invention, a step of drying the catalyst obtained in step a1) is carried out to form a presulfided catalyst.

The drying step makes it possible to remove the solvent resulting from the impregnation solution in the catalyst and causes the sulfurizing agent to decompose to form hydrogen sulphide (H ₂ S). The hydrogen sulphide (H ₂ S) thus formed makes it possible to form a presulphurized catalyst.

The drying step a2) is carried out at a temperature less than or equal to 200°C, advantageously between 15 and 150°C, preferably between 40°C and 130°C.

The drying step can be carried out by any technique known to those skilled in the art. The drying step is preferably carried out under an inert atmosphere or under an atmosphere containing oxygen. It is advantageously carried out at atmospheric pressure or at reduced pressure.

The drying step is advantageously carried out in a traversed bed using air or any other hot gas. Preferably, when the drying is carried out in a fixed bed, the gas used is either air or an inert gas such as argon or nitrogen. Very preferably, the drying is carried out in a traversed bed in the presence of nitrogen and/or air.

Preferably, the drying step lasts between 5 minutes and 4 hours, preferably between 10 minutes and 4 hours and very preferably between 30 minutes and 3 hours.

At the end of step a2) a presulphurized catalyst is obtained. The elements of group VIB and/or of group VIII are partially sulfurized in such a way that the molar ratio S/(elements of group VIB and/or of group VIII) is between 0.1 and 10, preferably between 0.25 and 5.

Stage b ) sulfurization

Step b1) of excess impregnation in hot acid solution

According to step b1) of the sulfurization process according to the invention, an excess impregnation step is carried out at a temperature between 50° C. and less than 200° C. of said presulphurized catalyst, in which said catalyst is brought into contact with an acid impregnation solution comprising a sulfurizing agent.

This impregnation step b1) differs from the first impregnation step a1) in that it is carried out in excess, in the presence of an acid and at a higher temperature. The acid promotes hydrolysis of the sulfurizing agent to form the hydrogen sulfide necessary for sulfurization in the impregnating solution. The hydrogen sulphide (H ₂ S) thus formed during stage b1) makes it possible to transform the presulphide catalyst into a sulphide catalyst.

The impregnation step b1) is carried out by one or more impregnations in excess of acid solution of said presulphurized catalyst, and preferably, by a single excess impregnation of said presulphurized catalyst. Excess impregnation consists of immersing the catalyst in a volume of solution (often greatly) greater than the pore volume of the catalyst, preferably keeping the system under stirring to improve the exchanges between the solution and the catalyst.

The impregnation step b1) is carried out at a temperature between 50°C and less than 200°C, preferably between 55°C and 160°C, and preferably between 60 and 100°C. The impregnation step b1) is carried out "hot", that is to say at a higher temperature than the temperature of the dry impregnation of step a1) in order to form the hydrogen sulphide necessary for sulfurization in the impregnation solution.

The impregnation solution must be acidic. The acid added to the impregnation solution can be chosen from an acid having a pKa of less than 7 and preferably less than 5. The acid can be a mineral acid, that is to say free of carbon atoms. , or an organic acid, that is to say one containing at least one carbon atom. For example, the acid can be a mineral acid chosen from hydrochloric acid, sulfuric acid, sulfurous acid, phosphoric acid, pyrophosphoric acid, phosphorous acid, nitric acid, nitrous acid, disulfuric acid, sulfamic acid, hydriodic acid, hydrobromic acid, perchloric acid and tetrafluoroboric acid. The acid can also be an organic acid chosen from methanesulfonic acid, 2,2'-dithiodiglycolic acid, 2,2'-thiodiacetic acid, 3,3'-dithiodipropionic acid, 3 ,3'-thiodipropionic acid, formic acid, acetic acid, oxalic acid, pyruvic acid, propanoic acid, lactic acid, thiolactic acid, glycolic acid, thioglycolic acid , diglycolic acid, 3-hydroxypropanoic acid, 3-hydroxybutanoic acid, 2-furoic acid, malonic acid, malic acid, thiomalic acid, tartaric acid, acid succinic acid, oxosuccinic acid, glutaric acid, α-ketoglutaric acid, acrylic acid, citric acid, maleic acid, fumaric acid, γ-ketovaleric acid and ascorbic acid .

Preferably, the acid is chosen from hydrochloric acid, sulfuric acid, sulfamic acid, formic acid, lactic acid and γ-ketovaleric acid.

The amount of acid added is preferably such that the acid introduced/sulphurizing agent molar ratio is greater than 5.10 ^-8 , preferably greater than 5.10 ^-6 , more preferably greater than 5.10 ^-5 and particularly preferably greater than 5.10 ^-3 .

The impregnation solution includes a sulfurizing agent. The sulfurizing agent is a compound comprising at least one sulfur atom. The sulfurizing agent comprises in particular a C=S function. The sulfurizing agent hydrolyzes in acidic solution and on heating to form hydrogen sulfide. The sulfurizing agent can be chosen from thioacetamide, thioacetic acid, thiourea, 1,3-dimethylthiourea, 1,3-diethylthiourea, 1,1,3,3-tetramethylthiourea, 2-thiouracil, rhodanine, Bis(dimethylthiocarbamyl) disulfide, O,O'-Diisopropyldithiobis(thioformate) and thiosemicarbazide. Preferably, the sulfurizing agent is thioacetamide, thioacetic acid or thiourea. Even more preferably, the sulfurizing agent is thioacetamide. Thioacetamide hydrolyses, in the presence of acid, into acetic acid, ammonia and hydrogen sulphide (H ₂ S).

The sulfurizing agent of step b1) may or may not be identical to the sulfurizing agent of step a1).

According to a variant of the invention, the sulfurizing agent can be added to the acid solution in several fractions over time.

The total quantity of sulfurizing agent added to the impregnation solution b1) is preferably such that the molar ratio S/(group VIB and/or group VIII elements) is between 1 and 200, preferably between 2 and 100 and preferably between 3 and 80.

The impregnation solution may comprise any polar solvent known to those skilled in the art. A list of the usual polar solvents as well as their dielectric constant can be found in the book “Solvents and Solvent Effects in Organic Chemistry”, C. Reichardt, Wiley-VCH, 3rd edition, 2003, pages 472-474. Said polar solvent used is advantageously chosen from a compound comprising one or more chemical functions chosen from an alcohol, sulphone, sulphoxide, ether, aldehyde, ketone, ester, carbonate, nitrile, amide function and water, taken alone or as a mixture. Said polar solvent can also advantageously be chosen from the group formed by methanol, ethanol, isopropanol, butanol-1, pentanol-1, 1,5-pentanediol, 1,6-hexanediol, water, phenol, cyclohexanol, a glycol, ethylene glycol, diethylene glycol, triethylene glycol, a polyethylene glycol (with a molecular weight between 200 and 1500 g/mol), propylene glycol, a glycol ether, 1-methoxy -2-propanol, 1-butoxy-2-propanol, 2-butoxyethanol, 2-(2-butoxyethoxy)ethanol, 2-(2-methoxyethoxy)ethanol, 2-(2-ethoxyethoxy)ethanol, 2-(2-butoxyethoxy)ethanol, 2-(2-hexyloxyethoxy)ethanol, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, triethylene glycol dimethyl ether, triethylene glycol methyl ether, triethylene glycol ethyl ether, triethylene glycol butyl ether, dipropylene glycol methyl ether, dipropylene glycol ethyl ether, dipropylene glycol n-propyl ether, dipropylene glycol n-butyl ether , tripropylene glycol methyl ether, tripropylene glycol n-butyl ether, a glycol acetate, glycerol, dioxane, propylene carbonate, ethyl acetate, DMSO (dimethyl sulfoxide), N-methylpyrrolidone (NMP) and sulfolane, taken alone or as a mixture.

Very preferably, the solvent used is chosen from 2-(2-methoxyethoxy)ethanol, 2-(2-ethoxyethoxy)ethanol, 2-(2-butoxyethoxy)ethanol, 2-(2-hexyloxyethoxy)ethanol , triethylene glycol methyl ether, triethylene glycol ethyl ether, dipropylene glycol n-butyl ether, tripropylene glycol methyl ether, tripropylene glycol n-butyl ether and water, taken alone or as a mixture. The solvent may contain water. Since step b1) is carried out by excess impregnation, there are no constraints on the volume. The solvent used during step b1) can therefore be less polar than that of step a1).

The impregnation solution of step b1) thus generally comprises a polar solvent, an acid and the sulfurizing agent. Preferably, the impregnation solution consists of a polar solvent, an acid and a sulfurizing agent, and in a particularly preferred manner, it consists of a polar solvent, acid and thioacetamide.

Preferably, the impregnation step b1) generally lasts between 10 minutes and 12 hours and preferably between 30 minutes and 4 hours.

The impregnation step can be carried out under pressure, for example at less than 10 MPa (100 bar), preferably at less than 5 MPa (50 bar) and preferably at a pressure less than or equal to the autogenous pressure. According to a variant of the invention, it is carried out under reflux at atmospheric pressure.

Advantageously, the elements of group VIB and/or of group VIII are sulfurized in such a way that the molar ratio S/(elements of group VIB and/or of group VIII) is greater than 1, preferably between 1.3 and 10 , preferably between 1.4 and 6 and even more preferably between 1.8 and 4.

Advantageously, after each impregnation step, the impregnated catalyst is allowed to mature. The maturation allows the impregnation solution to diffuse homogeneously within the porosity of the catalyst.

Any maturation step described in the present invention is advantageously carried out at atmospheric pressure, in an atmosphere saturated with solvent and at a temperature between 17° C. and 50° C., and preferably at room temperature. Generally, a maturation period of between ten minutes and forty-eight hours, and preferably between thirty minutes and five hours, is sufficient. Longer durations are not excluded, but do not necessarily bring improvement.

When several impregnation steps are carried out, each impregnation step is preferably followed by an intermediate drying step such as the drying step b2) described below.

Stage b2 ) Drying

According to step b2) of the sulfurization process according to the invention, a step of drying the catalyst obtained in step b1) is carried out to form a sulfurized catalyst.

The drying step removes the solvent from the impregnation solution in the catalyst. Step b2) of drying can be carried out in the same way and at the same temperature as step a2) of drying.

The drying step b2) is carried out at a temperature less than or equal to 200°C, advantageously between 15 and 150°C, preferably between 40°C and 130°C.

The drying step can be carried out by any technique known to those skilled in the art. The drying step is preferably carried out under an inert atmosphere or under an atmosphere containing oxygen. It is advantageously carried out at atmospheric pressure or at reduced pressure.

The drying step is advantageously carried out in a traversed bed using air or any other hot gas. Preferably, when the drying is carried out in a fixed bed, the gas used is either air or an inert gas such as argon or nitrogen. Very preferably, the drying is carried out in a traversed bed in the presence of nitrogen and/or air.

Preferably, the drying step lasts between 5 minutes and 4 hours, preferably between 10 minutes and 4 hours and very preferably between 30 minutes and 3 hours.

Stage activation vs ) (option nally )

The process according to the invention can also comprise an activation step c) carried out after the sulfurization step b).

Activation step c) is a heat treatment step in which said sulfur catalyst is brought into contact with an inert or reducing gas stream. In the case of an inert flux, the activation step c) is generally carried out at a temperature between 200 and 450°C, preferably between 250 and 400°C.

In the case of a reducing flow, the activation step c) is generally carried out at a temperature between 50 and 450°C, preferably between 100 and 350°C.

The activation step makes it possible to transform the sulfur catalyst (for example in the form of Ni—MoS ₃ when the active phase is based on nickel and molybdenum) into an active sulfur catalyst (for example in Ni—MoS ₂ ).

The activation step can be carried out according to any method known to those skilled in the art.

According to a first embodiment, it can be carried out without addition of sulfurizing agent. Indeed, the catalyst being already sulfurized, such an addition is not necessary.

The inert stream can be a stream comprising nitrogen. Preferably, the inert stream consists of nitrogen.

The reducing stream can be a stream comprising hydrogen, preferably a stream consisting of hydrogen.

The activation step is generally carried out at an absolute pressure of between 0.1 and 0.5 MPa, preferably between 0.1 and 0.2 MPa.

The activation step is carried out with an inert or reducing gas flow with an hourly volume velocity expressed in h ^-1 of between 100 and 2000, preferably between 250 and 1000.

According to a second embodiment, hydrogen sulphide H ₂ S may be present in the inert or reducing gas stream. When it is present, the content by volume of H ₂ S in the inert or reducing gas stream can be comprised, without limitation, between 5 and 25%, preferably between 10 and 20%.

According to a third embodiment, the activation step c) can be carried out in the presence of a hydrocarbon charge with or without the addition of a sulfur compound. According to this embodiment, the activation step is carried out in a conventional manner by methods well known to those skilled in the art, and advantageously under a (sulfo)-reducing atmosphere in the presence of hydrogen and optionally of hydrogen sulfide formed by the decomposition of a sulfurizing agent (spiking agent according to Anglo-Saxon terminology) or resulting from the charge. Sulfurizing agents are elemental sulfur, CS₂, mercaptans, sulphides and/or polysulphides, hydrocarbon cuts with a boiling point below 400°C containing sulfur compounds or any other compound containing sulfur used for the activation of hydrocarbon feedstocks with a view to sulphurizing the catalyst. Said compounds containing sulfur are advantageously chosen from alkyl disulphides such as for example dimethyl disulphide (DMDS), alkyl sulphides, such as for example dimethyl sulphide, thiols such as for example n- butyl mercaptan (or 1-butanethiol) and polysulphide compounds of the tertiononylpolysulphide type.

According to this third embodiment, the activation step is carried out at an absolute pressure of between 0.5 and 20 MPa, preferably between 1 and 16 MPa.

According to this third embodiment, the activation step is carried out with a feed stream with an hourly volume velocity expressed in h ^-1 of between 0.5 and 10, preferably between 1 and 4.

According to this third embodiment, the hydrogen to charge ratio expressed in volume of hydrogen, measured under normal temperature and pressure conditions, per volume of liquid charge is between 100 and 1500 NL/L, preferably between 300 and 1200 NL/L.

Very preferably, the activation step is carried out in the presence of hydrogen and a hydrocarbon charge without addition of sulfurizing agent.

The catalyst obtained by the sulfurization process according to the invention has a high degree of sulfurization. The sulfurization rate of the metals constituting the catalysts is at least equal to 90%, preferably at least equal to 95%. The sulfur content in the sulfurized catalyst is measured by elemental analysis according to ASTM D5373. The sulfurization rate is defined as the ratio between the experimental S/(metals) and theoretical S/(metals) molar ratios, multiplied by 100; the theoretical ratio corresponding to the total transformation of metal oxides into sulphides.

in which :

(S/metal) _catalyst is the molar ratio between the sulfur (S) and the metal present on the catalyst

(S/metal) _theoretical is the molar ratio between the sulfur and the metal corresponding to the total sulphidation of the metal in sulphide.

This theoretical molar ratio varies according to the metal considered:
- (S/Co) _theoretical = 8/9
- (S/Ni) _theoretical = 2/3
- (S/Mo) _theoretical =2/1
- (S/W) _theoretical =2/1

When the catalyst comprises several metals, the molar ratio between the sulfur present on the catalyst and all the metals must also be at least equal to 90% of the theoretical molar ratio corresponding to the total sulphidation of each metal to sulphide, the calculation being carried out in proportion to the relative molar fractions of each metal.

For example, for a catalyst comprising molybdenum and nickel with a respective molar fraction of 0.7 and 0.3, the minimum molar ratio (S/ Mo + Ni) is given by the relationship:

Catalyst that can be subjected to the sulfurization process

The catalyst subjected to the sulfurization process according to the invention comprises a porous support, at least one element from group VIB and/or at least one element from group VIII and at least one organic compound. It may additionally contain phosphorus, other dopants such as boron and/or fluorine.

The hydrogenating function of said sulfurizing catalyst, also called active phase, is ensured by at least one element from group VIB and/or by at least one element from group VIII.

Preferred Group VIB elements are molybdenum and tungsten. Preferred group VIII elements are non-noble elements and in particular cobalt and nickel. Advantageously, the hydrogenating function is chosen from the group formed by combinations of the elements cobalt-molybdenum, nickel-molybdenum, nickel-tungsten or nickel-cobalt-molybdenum, or nickel-molybdenum-tungsten.

In the case where a significant activity in hydrodesulphurization, or in hydrodenitrogenation and in hydrogenation of aromatics is desired, the hydrogenating function is advantageously provided by the combination of nickel and molybdenum; a combination of nickel and tungsten in the presence of molybdenum can also be advantageous. In the case of charges of the vacuum distillate or heavier type, combinations of the cobalt-nickel-molybdenum type can be advantageously used.

The content of group VIB element is between 5 and 40% by weight, preferably between 8 and 35% by weight, and more preferably between 10 and 30% by weight expressed as group VIB metal oxide relative to the total weight of the catalyst. When the metal is molybdenum or tungsten, the metal content is expressed as MoO ₃ or WO ₃ respectively.

The content of group VIII element is between 1 and 10% by weight, preferably between 1.5 and 9% by weight, and more preferably between 2 and 8% by weight expressed as group VIII metal oxide relative to the weight total catalyst. When the metal is cobalt or nickel, the metal content is expressed as CoO or NiO respectively.

The total content of group VIB and group VIII elements is advantageously greater than 6% by weight, expressed as oxide relative to the total weight of the catalyst.

The molar ratio of group VIII element to group VIB element in the catalyst is preferably between 0.1 and 0.8, preferably between 0.15 and 0.6 and even more preferably between 0.2 and 0.5.

The catalyst to be sulfurized comprises at least one organic compound. The organic compound is an organic compound containing oxygen and/or nitrogen and/or sulfur. Generally, the organic compound is chosen from a compound comprising one or more chemical functions chosen from a carboxylic function, alcohol, thiol, thioether, sulphone, sulphoxide, ether, aldehyde, ketone, ester, carbonate, amine, nitrile, imide, oxime, urea and amide, or a compound including a furan ring or even a sugar.

The organic compound containing oxygen can be one or more chosen from compounds comprising one or more chemical functions chosen from a carboxylic, alcohol, ether, aldehyde, ketone, ester or carbonate function or else compounds including a furan cycle. or sugars. Here, an organic compound containing oxygen is understood to mean a compound containing no other heteroatom. By way of example, the organic compound containing oxygen can be one or more chosen from the group consisting of ethylene glycol, diethylene glycol, triethylene glycol, a polyethylene glycol (with a molecular weight of between 200 and 1500 g /mol), propylene glycol, 2-butoxyethanol, 2-(2-butoxyethoxy)ethanol, 2-(2-methoxyethoxy)ethanol, triethyleneglycoldimethylether, glycerol, acetophenone, 2,4-pentanedione, pentanone, acetic acid, oxalic acid, maleic acid, malic acid, malonic acid, oxalic acid, gluconic acid, tartaric acid, citric acid, γ- acid ketovaleric, a dialkyl C1-C4 succinate and more particularly dimethyl succinate, methyl acetoacetate, ethyl acetoacetate, 2-methoxyethyl 3-oxobutanoate, 2-methacryloyloxyethyl 3-oxobutanoate, dibenzofuran , a crown ether, orthophthalic acid, glucose, fructose, sucrose, sorbitol, xylitol, γ-valerolactone, 2-acetylbutyrolactone, propylene carbonate, 2-furaldehyde (also known as furfural), 5-hydroxymethylfurfural (also known as 5-(hydroxymethyl)-2-furaldehyde or 5- HMF), 2-acetylfuran, 5-methyl-2-furaldehyde, methyl 2-furoate, furfuryl alcohol (also known as furfuranol), furfuryl acetate, ascorbic acid, lactate ethyl lactate, butyl butyryllactate, ethyl 3-hydroxybutanoate, ethyl 3-ethoxypropanoate, methyl 3-methoxypropanoate, 2-ethoxyethyl acetate, 2- butoxyethyl, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,5-hexanediol, 3-ethyl-1,5 -pentanediol, 2,4-diethyl-1,5-pentanediol, 5-methyl-2(3H)-furanone, butyl glycolate, ethyl 4-oxo-pentanoate, diethyl maleate, maleate dimethyl, dimethyl fumarate, diethyl fumarate , dimethyl adipate, dimethyl 3-oxoglutarate, dimethyl tartrate, diethyl tartrate, diisopropyl tartrate, di-tert-butyl tartrate, dimethyl malate, diethyl malate, malate diisopropyl and dibutyl malate.

The organic compound containing nitrogen can be one or more chosen from compounds comprising one or more chemical functions chosen from an amine or nitrile function. Here, an organic compound containing nitrogen is understood to mean a compound containing no other heteroatom. By way of example, the organic compound containing nitrogen can be one or more selected from the group consisting of ethylenediamine, diethylenetriamine, hexamethylenediamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, acetonitrile , octylamine, guanidine or a carbazole.

The organic compound containing oxygen and nitrogen can be one or more chosen from compounds comprising one or more chemical functions chosen from a carboxylic acid, alcohol, ether, aldehyde, ketone, ester, carbonate, amine function. , nitrile, imide, amide, urea or oxime. Here, an organic compound containing oxygen and nitrogen is understood to mean a compound containing no other heteroatom. By way of example, the organic compound containing oxygen and nitrogen can be one or more chosen from the group consisting of 1,2-cyclohexanediaminetetraacetic acid, monoethanolamine (MEA), 1- methyl-2-pyrrolidinone, dimethylformamide, ethylenediaminetetraacetic acid (EDTA), alanine, glycine, nitrilotriacetic acid (NTA), N-(2-hydroxyethyl)ethylenediamine-N,N′,N acid ′-triacetic acid (HEDTA), diethylene-triaminepentaacetic acid (DTPA), tetramethylurea, glutamic acid, dimethylglyoxime, bicine, tricine, 2-methoxyethyl cyanoacetate, 1-ethyl-2-pyrrolidinone, 1-vinyl-2-pyrrolidinone, 1,3-dimethyl-2-imidazolidinone, 1-(2-hydroxyethyl)-2-pyrrolidinone, 1-(2-hydroxyethyl)-2,5-pyrrolidinedione, 1 -methyl-2-piperidinone, 1-acetyl-2-azepanone, 1-vinyl-2-azepanone and 4-aminobutanoic acid.

The organic compound containing sulfur can be one or more chosen from compounds comprising one or more chemical functions chosen from a thiol, thioether, sulphone or sulphoxide function. The organic compound containing sulfur is an organic compound allowing to increase the dispersion of the active phase thus leading to a more active catalyst. It is understood that the organic compound containing sulfur is not the sulphurizing agent allowing the sulphidation to be carried out. The organic compound in particular does not contain a C=S function. By way of example, the organic compound containing sulfur can be one or more selected from the group consisting of thioglycolic acid, 2,2'-thiodiethanol, 2-hydroxy-4-methylthiobutanoic acid, a sulfonated derivative of a benzothiophene or a sulfoxide derivative of a benzothiophene, ethyl 2-mercaptopropanoate, methyl 3-(methylthio)propanoate and ethyl 3-(methylthio)propanoate.

Preferably, the organic compound is chosen from γ-valerolactone, 2-acetylbutyrolactone, triethylene glycol, diethylene glycol, ethylene glycol, ethylenediaminetetraacetic acid (EDTA), maleic acid, malonic acid, citric acid, acetic acid, oxalic acid, gluconic acid, glucose, fructose, sucrose, sorbitol, xylitol, γ-ketovaleric acid, a C1-C4 dialkyl succinate and more especially dimethyl succinate, 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 lactate, butyl butyryllactate, ethyl 3-hydroxybutanoate, ethyl 3-ethoxypropanoate, 2-ethoxy acetate ethyl acetate, 2-butoxyethyl acetate, 2-hydroxyethyl acrylate, 1-vinyl-2-pyrrolidinone, 1,3-dimethyl-2-imidazolidinone, 1,5-pentanediol, 1-(2- hydroxyethyl)-2-pyrrolidinone, 1-(2-hydroxyethyl)-2,5-pyrrolidinedione, 5-methyl-2(3H)-furanone, 1-methyl-2-piperidinone, 4-aminobutanoic acid, Butyl Glycolate, Ethyl 2-Mercaptopropanoate, Ethyl 4-Oxopentanoate, Diethyl Maleate, Dimethyl Maleate, Dimethyl Fumarate, Diethyl Fumarate, Dimethyl Adipate, 3-Oxoglutarate dimethyl, diethyl tartrate and diethyl malate.

The total content of organic compound(s) containing oxygen and/or nitrogen and/or sulfur present in the sulfur catalyst is generally between 1 and 30% by weight relative to the weight total catalyst.

The catalyst to be sulfurized comprises a porous support. Preferably, the support is a support based on alumina or silica or silica-alumina.

When the support of said catalyst is based on alumina, it contains more than 50% by weight of alumina relative to the total weight of the support and, in general, it contains only alumina or silica-alumina such as defined below.

Preferably, the support comprises alumina, and preferably extruded alumina. Preferably, the alumina is gamma alumina.

The alumina support advantageously has a total pore volume of between 0.1 and 1.5 cm ³ .g ^-1 , preferably between 0.4 and 1.1 cm ³ .g ^-1 . The total porous volume is measured by mercury porosimetry according to the ASTM D4284 standard with a wetting angle of 140°, as described in the work Rouquerol F.; Rouquerol J.; Singh K. “Adsorption by Powders & Porous Solids: Principle, methodology and applications”, Academic Press, 1999, for example by means of an Autopore III™ model apparatus from the Micromeritics™ brand.

The specific surface of the alumina support is advantageously between 5 and 400 m ² .g ^-1 , preferably between 10 and 350 m ² .g ^-1 , more preferably between 40 and 350 m ² .g ^{-1 .} . The specific surface is determined in the present invention by the BET method according to standard ASTM D3663, method described in the same work cited above.

In another preferred case, the support of said catalyst is a silica-alumina containing at least 50% by weight of alumina relative to the total weight of the support. The silica content in the support is at most 50% by weight relative to the total weight of the support, usually less than or equal to 45% by weight, preferably less than or equal to 40%.

Silicon sources are well known to those skilled in the art. Mention may be made, by way of example, of silicic acid, silica in powder form or in colloidal form (silica sol), tetraethylorthosilicate Si(OEt) ₄ .

When the support of said catalyst is based on silica, it contains more than 50% by weight of silica relative to the total weight of the support and, in general, it contains only silica.

According to a particularly preferred variant, the porous support consists of alumina, silica or silica-alumina.

The support may also advantageously also contain from 0.1 to 70% by weight of zeolite relative to the total weight of the support. In this case, all the sources of zeolite and all the methods of associated preparations known to those skilled in the art can be incorporated. Preferably, the zeolite is chosen from the group FAU, BEA, ISV, IWR, IWW, MEI, UWY and preferably, the zeolite is chosen from the group FAU and BEA, such as Y and/or beta zeolite, and particularly preferably such as USY and/or beta zeolite.

The catalyst is advantageously in the form of balls, extrudates (for example trilobes or quadrilobes), pellets or irregular and non-spherical agglomerates, the specific shape of which may result from a crushing step.

The catalyst to be sulfurized advantageously also comprises phosphorus as dopant. The dopant is an added element which in itself has no catalytic character but which increases the catalytic activity of the active phase.

The phosphorus content in said catalyst is preferably between 0.1 and 20% by weight, expressed as P ₂ O ₅ relative to the total weight of the catalyst, preferably between 0.2 and 15% by weight, and very preferably between 0.3 and 11% by weight.

The phosphorus molar ratio to the group VIB element 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 very preferably between 0.15 and 0.8.

The contents of group VIII and group VIB metals are measured by X-ray fluorescence.

The group VIB element, group VIII element and phosphorus contents in the catalyst are expressed in oxides after correction of the loss on ignition of the catalyst sample at 550°C for two hours in a muffle furnace. Loss on ignition is due to moisture loss. It is determined according to ASTM D7348.

The catalyst to be sulfurized, with or without phosphorus, can advantageously also contain at least one dopant chosen from boron, fluorine and a mixture of boron and fluorine.

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

Said catalyst to be sulfurized according to the sulfurization process according to the invention can be a fresh or rejuvenated catalyst requiring activation or re-activation by sulfurization. This catalyst can be obtained by any method known to those skilled in the art.

According to a first variant, the catalyst to be sulfurized according to the sulfurization process according to the invention can be a fresh catalyst, that is to say a catalyst which has not been used as a catalyst before in a catalytic unit and in particular in hydrotreating and/or hydrocracking.

The preparation of the fresh catalyst is known and generally comprises a step of impregnating the elements of group VIII and/or group VIB, and optionally phosphorus and/or an organic compound on the porous support, followed by drying and optionally calcination.

The impregnation step can be carried out either by slurry impregnation, or by excess impregnation, or by dry impregnation, or by any other means known to those skilled in the art. The impregnation step is carried out by one or more impregnations in excess of solution on the support, or preferably by one or more dry impregnations, and, preferably, by a single dry impregnation of said catalyst. When several impregnation steps are carried out, each impregnation step is preferably followed by an intermediate drying step such as the drying step described below.

By way of example, among the sources of molybdenum, use may be made of oxides and hydroxides, molybdic acids and their salts, in particular ammonium salts such as ammonium molybdate, ammonium heptamolybdate, phosphomolybdic acid (H ₃ PMo ₁₂ O ₄₀ ), and their salts, and optionally silicomolybdic acid (H ₄ SiMo ₁₂ O ₄₀ ) and its salts. The sources of molybdenum can also be any heteropolycompound of Keggin, lacunary Keggin, substituted Keggin, Dawson, Anderson, Strandberg type, for example. Preferably, molybdenum trioxide and the heteropolycompounds of Keggin, lacunary Keggin, substituted Keggin and Strandberg type are used.

The tungsten precursors which can be used are also well known to those skilled in the art. For example, among the sources of tungsten, it is possible to use oxides and hydroxides, tungstic acids and their salts, in particular ammonium salts such as ammonium tungstate, ammonium metatungstate, phosphotungstic acid and their salts, and optionally silicotungstic acid (H ₄ SiW ₁₂ O ₄₀ ) and its salts. The tungsten sources can also be any heteropolycompound of Keggin, lacunary Keggin, substituted Keggin, Dawson type, for example. Preferably, ammonium oxides and salts are used, such as ammonium metatungstate or heteropolyanions of Keggin, lacunary Keggin or substituted Keggin type.

The cobalt precursors which can be used are advantageously chosen from oxides, hydroxides, hydroxycarbonates, carbonates and nitrates, for example. Cobalt hydroxide and cobalt carbonate are preferably used.

The nickel precursors which can be used are advantageously chosen from oxides, hydroxides, hydroxycarbonates, carbonates and nitrates, for example. Nickel hydroxide and nickel hydroxycarbonate are preferably used.

The preferred phosphorus precursor is orthophosphoric acid H ₃ PO ₄ , but its salts and esters such as ammonium phosphates are also suitable. The phosphorus can also be introduced at the same time as the element(s) of group VIB in the form of heteropolyanions of Keggin, lacunary Keggin, substituted Keggin or of the Strandberg type.

When the catalyst also comprises a dopant chosen from boron, fluorine or a mixture of boron and fluorine, the introduction of this (these) dopant(s) can be done in the same way as the introduction of phosphorus.

The organic compound can be introduced into the catalyst by an impregnation step. The introduction of the organic compound can be carried out either at the same time as the impregnation of the metals (co-impregnation), or after (post-impregnation), or before (pre-impregnation). In addition, the modes of implementation can be combined.

The molar ratio of the added organic compound per group VIB metal 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 very preferably between 0.1 and 1.5 mol/mol.

The molar ratio of the added organic compound per group VIII metal is between 0.02 and 17 mol/mol, preferably between 0.1 and 10 mol/mol, preferably between 0.15 and 5 mol/mol. and very preferably between 0.6 and 3.5 mol/mol.

When more than one organic compound is present, the different molar ratios apply for each of the organic compounds present.

The impregnation solution can comprise any polar solvent known to those skilled in the art and in particular those described in step a1) or b1). The solvent may contain water. Preferably, a polar protic solvent is used. Very preferably, the solvent used is water or ethanol or a mixture of ethanol and water. In a variant, the organic compound is introduced without solvent if it is liquid under the conditions of its implementation.

Advantageously, after each impregnation step, the impregnated catalyst is allowed to mature under the conditions described in steps a1) or b1).

The catalyst thus impregnated can then be subjected to a drying step at a temperature below 200° C., advantageously between 50° C. and 180° C., preferably between 70° C. and 150° C., very preferably between 75° C. °C and 130°C. The drying step is carried out according to the conditions described for steps a2) or b2).

When performing several impregnation steps, each impregnation step is preferably followed by an intermediate drying step.

According to a preferred variant, the preparation of the fresh catalyst does not include a calcination step after the introduction of the organic compound in order to at least partially preserve the organic compound. Here, calcination means a heat treatment under a gas containing air or oxygen at a temperature greater than or equal to 200°C. The drying is then carried out so as to preferably retain at least 30% of the organic compound introduced during an impregnation step, preferably this quantity is greater than 50% and even more preferably, greater than 70%, calculated on the carbon base remaining on the catalyst.

According to another variant, the preparation of the fresh catalyst can include a calcination step. The calcination step is generally carried out at a temperature between 200°C and 600°C, preferably between 250°C and 550°C, under an inert atmosphere (nitrogen for example) or under an atmosphere containing oxygen (air for example). The duration of this heat treatment is generally between 0.5 hours and 16 hours, preferably between 1 hour and 5 hours. It is important to emphasize that the preparation of the fresh catalyst does not include a calcination step after the introduction of the organic compound in order to at least partially preserve the organic compound in the catalyst. However, the catalyst precursor may undergo a calcination step before the introduction of the organic compound, in particular after the impregnation of the elements of group VIB and VIII (post-impregnation) optionally in the presence of phosphorus and/or another dopant .

The organic compound can also be introduced into the catalyst by a gas phase contacting step as described in applications FR3065887 and FR3065888. According to these variants, the method for preparing said catalyst does not involve a conventional step of impregnating said organic compound. Consequently, it is not necessary to carry out a drying step after introduction of the organic compound. According to these variants, the organic compound can be introduced before or after the introduction of the metals and optionally of the phosphorus, said introduction of the metals and optionally of the phosphorus being carried out by impregnation.

According to the first of the three variants, the introduction of the organic compound into the support or the catalyst is carried out by implementing a step in which the said support or catalyst and the organic compound are brought together simultaneously in the liquid state and without contact. between the support or catalyst and the organic compound in the liquid state, at a temperature below the boiling point of the organic compound and under conditions of pressure and duration such that a fraction of said organic compound is transferred to the gaseous state to the support or catalyst. This variant is characterized in that the addition of the organic compound to the support or catalyst is carried out without physical contact with the organic compound in the liquid state, that is to say without impregnation of the support or catalyst by the liquid. . The process is based on the principle of the existence of a vapor pressure of the organic compound which is generated by its liquid phase at a given temperature and pressure. Thus a part of the molecules of organic compound in the liquid state changes to the gaseous state (vaporization) and is then transferred (via a gaseous route) to the support or catalyst. This bringing together step is carried out for a sufficient time to reach the targeted content of organic compound on the catalyst.

Generally, this step is carried out at an absolute pressure of between 0 and 1 MPa.

Preferably, the temperature for carrying out this step is below 200°C, preferably between 10°C and 150°C, more preferably between 25°C and 120°C.

According to the second of the three gas phase variants, the introduction of the organic compound into the support or the catalyst is carried out by implementing a step in which the support or catalyst is brought into contact, in a closed or open chamber, with a solid containing at least one organic compound, this step being carried out under conditions of temperature, pressure and time such that a fraction of said organic compound is transferred by gas from the porous solid to the support or catalyst. According to this second variant, the addition of the organic compound consists in bringing together, in an open or closed enclosure, a first batch of porous solid rich in an organic compound which has been previously deposited on said solid in the liquid state with a support or catalyst (second batch of porous solid poor in said organic compound). The objective is to allow gaseous transfer of part of the organic compound contained in the first batch of porous solid into the support or catalyst. The term “poor in organic compound” covers in particular the case where the second batch of porous solid (support or catalyst) is free of said organic compound. This second variant is also based on the principle of the existence of a vapor pressure of the organic compound at a given temperature and pressure. Thus a part of the molecules of organic compound of the batch of porous solid rich in organic compound passes in gaseous form (vaporization) and is then transferred (via a gaseous route) to the support or catalyst (solid poor in organic compound). According to the invention, the porous solid rich in organic compound acts as a source of organic compound to enrich the support or catalyst with organic compound (porous solid poor in organic compound).

The porous solid rich in organic compound is advantageously a porous support, preferably a support based on alumina or silica or silica-alumina which may contain at least one element from group VIB, at least one element from group VIII, and optionally phosphorus.

The mass ratio (first batch of solid rich in organic compound) / (support or catalyst or second batch of solid poor in organic compound) depends on the porous distribution of the solids and the objective in terms of targeted quantity of organic compound on the solids. This mass ratio is generally less than or equal to 10, preferably less than 2 and even more preferably between 0.05 and 1, limits included.

This step of introducing the organic compound is preferably carried out under controlled temperature and pressure conditions and so that the temperature is lower than the boiling point of said organic compound to be transferred by gaseous route. Preferably, the processing temperature is below 150° C. and the absolute pressure is generally between 0 and 1 MPa, preferably between 0 and 0.5 MPa and more preferably between 0 and 0.2 MPa . It will thus be possible to carry out the contacting step in an open or closed enclosure, possibly with a control of the composition of the gas present in the enclosure.

When the introduction of the organic compound is done in an open enclosure, it will be ensured that the entrainment of the organic compound outside the enclosure is limited as much as possible. Preferably, the introduction of the organic compound can be carried out in a closed enclosure.

The term “contact” designates the fact that the solids are present at the same time in the enclosure without there necessarily being physical contact between the two batches of solids.

The term "rich in organic compound" reflects the fact that the solid contains more than 50% of the total amount of said organic compound used in the step of impregnating the organic compound, preferably at least 60%, preferably at least least 80%, preferably at least 90% and preferably 100%. According to one embodiment, at the start of the step of impregnating the organic compound, the porous solid rich in organic compound contains 100% of the total quantity involved in the step of impregnating the organic compound and the support or catalyst (second batch of solid poor in organic compound) therefore contains 0% of the total amount of said organic compound.

According to the third of the three gas phase variants, the step of impregnating the organic compound is carried out by depositing at least one organic compound on the support or catalyst by supplying an initial batch of support or catalyst, by heterogeneously impregnating the initial batch of support or catalyst with the organic compound in the liquid state so as to provide a first batch of support or catalyst rich in organic compound and a second batch of support or catalyst poor in organic compound, and leaving said batches of support in the presence or catalyst under conditions of temperature, pressure and time such that a fraction of said organic compound is transferred by gas from the first batch of support or catalyst to the second batch of support or catalyst.

This step of impregnating the organic compound is preferably carried out under controlled temperature and pressure conditions and so that the temperature is lower than the boiling point of said organic compound to be transferred by gas. Preferably, the processing temperature is below 150° C. and the absolute pressure is generally between 0 and 1 MPa, preferably between 0 and 0.5 MPa and more preferably between 0 and 0.2 MPa . The organic compound impregnation step can thus be carried out in an open or closed enclosure, possibly with control of the composition of the gas present in the enclosure.

When the organic compound impregnation step is done in an open enclosure, it will be ensured that the entrainment of the organic compound outside the enclosure is limited as much as possible. Preferably, the organic compound impregnation step is carried out in a closed enclosure, for example in a solid storage or transport container impervious to gas exchange with the external environment.

The additive catalyst obtained by the introduction of the organic compound by gas phase as described above can also be treated by one or more subsequent stages in order to incorporate one or more other additional organic compounds different from that employed in stage d. impregnation of the organic compound. The incorporation of one or more other different additional organic compounds can be carried out by means of gas phase addition processes or according to any other method known to those skilled in the art, such as for example by impregnation of a solution containing the compound additional organic.

According to a second variant, the catalyst to be sulfurized according to the sulfurization process according to the invention can also be a rejuvenated catalyst. The rejuvenated catalyst is a catalyst which has been used as a catalyst in a catalytic unit and in particular in hydrotreating and/or hydrocracking and which has been subjected to at least one regeneration stage then to at least one rejuvenation stage followed by a drying step and optionally a calcining step.

The regeneration step can be carried out by any means known to those skilled in the art. Regeneration is generally carried out by calcination at temperatures between 350 and 550°C, and most often between 400 and 520°C, or between 420 and 520°C, or even between 450 and 520°C, lower temperatures at 500° C. being often advantageous. Following regeneration, the hydrogenating function comprising the elements of group VIB and/or of group VIII of the regenerated catalyst is in an oxide form.

The rejuvenation step consists of reimpregnating the regenerated catalyst with a solution containing at least one organic compound (additive) and/or metal precursors and possibly phosphorus. Just as in the case of the preparation of a fresh catalyst, the organic compound can be introduced into the catalyst by an impregnation step either at the same time as the impregnation of the metals (co-impregnation), or after (post-impregnation). impregnation), either before (pre-impregnation), or even without the metals. The organic compound can also be introduced into the catalyst by a gas phase contacting step as described above.

The catalyst impregnated with the organic compound is then subjected to a drying step under the conditions as described above. The different modes of introduction of the organic compound, the quantities used in the impregnation solution, as well as the presence or not and the nature of the solvent, are as described for the preparation of the fresh catalyst. The rejuvenated catalyst can undergo a calcination step under the conditions as described above.

Hydrotreating and/or hydrocracking process

Finally, another object of the invention is the use of the catalyst prepared by the sulfurization process according to the invention in processes for the hydrotreating and/or hydrocracking of hydrocarbon cuts.

The process for hydrotreating and/or hydrocracking hydrocarbon cuts can be carried out in one or more reactors in series of the fixed bed type or of the bubbling bed type.

The process for hydrotreating and/or hydrocracking hydrocarbon cuts is carried out in the presence of the catalyst prepared by the sulfurization process according to the invention. It can also be carried out in the presence of a mixture of the catalyst prepared by the sulfurization process according to the invention and a catalyst prepared by another sulfurization process, and this whether it is a fresh catalyst, regenerated or at least partially worn.

The catalyst prepared according to the sulfurization process according to the invention is advantageously used for hydrotreating and/or hydrocracking reactions of hydrocarbon feedstocks such as petroleum cuts, cuts from coal or hydrocarbons produced from natural gas. , optionally in mixtures or also from a hydrocarbon fraction derived from biomass and more particularly for hydrogenation, hydrodenitrogenation, hydrodearomatization, hydrodesulfurization, hydrodeoxygenation, hydrodemetallization or hydroconversion reactions hydrocarbon fillers.

This catalyst can also advantageously be used during the pretreatment of catalytic cracking or hydrocracking feeds, or the hydrodesulfurization of residues or the extensive hydrodesulfurization of gas oils (ULSD Ultra Low Sulfur Diesel according to the Anglo-Saxon terminology).

The feedstocks used in the hydrotreating process are, for example, gasolines, gas oils, vacuum gas oils, atmospheric residues, vacuum residues, atmospheric distillates, vacuum distillates, heavy fuel oils, oils, waxes and paraffins, waste oils, residues or deasphalted crudes, fillers from thermal or catalytic conversion processes, lignocellulosic fillers or more generally fillers from biomass such as vegetable oils, taken alone or in a mixture. The fillers which are treated, and in particular those cited above, generally contain heteroatoms such as sulphur, oxygen and nitrogen and, for heavy fillers, they most often also contain metals.

The operating conditions used in the processes implementing the hydrocarbon feedstock hydrotreating reactions 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 volume velocity is advantageously between 0.1 and 20 h ^-1 and preferably between 0.2 and 5 h ^-1 , and the hydrogen/feed ratio expressed as volume of hydrogen, measured under normal temperature and pressure conditions, per volume of liquid feed is advantageously between 50 to 5000 L/L and preferably 80 to 2000 L/L.

According to a first mode of use, said hydrotreating process is a hydrotreating process, and in particular hydrodesulfurization (HDS) of a gas oil cut carried out in the presence of at least one catalyst prepared according to the invention. Said hydrotreatment process aims to eliminate the sulfur compounds present in said gas oil cut so as to achieve the environmental standards in force, namely an authorized sulfur content of up to 10 ppm. It also makes it possible to reduce the aromatic and nitrogen contents of the gas oil cut to be hydrotreated.

Said gas oil cut to be hydrotreated contains from 0.02 to 5.0% by weight of sulphur. It is advantageously derived from direct distillation (or straight run gas oil according to Anglo-Saxon terminology), from a coking unit (coking according to Anglo-Saxon terminology), from a visbreaking unit (visbreaking according to Anglo-Saxon terminology). Saxon), a steam cracking unit (steam cracking according to the Anglo-Saxon terminology), a hydrotreating and/or hydrocracking unit for heavier loads and/or a catalytic cracking unit (Fluid Catalytic Cracking according to Anglo-Saxon terminology). Said diesel fraction preferably has at least 90% of the compounds whose boiling point is between 250° C. and 400° C. at atmospheric pressure.

The method for hydrotreating said diesel fraction according to the invention is implemented under the following operating conditions: a temperature between 200°C and 400°C, preferably between 300°C and 380°C, a total pressure between 2 MPa and 10 MPa and more preferably between 3 MPa and 8 MPa with a ratio of volume of hydrogen per volume of hydrocarbon charge, expressed in volume of hydrogen, measured under normal temperature and pressure conditions, per volume of liquid charge, between 100 and 600 L/L and more preferentially between 200 and 400 L/L and an hourly volumetric velocity (VVH) of between 0.5 and 10 h ^-1 , preferentially between 0.7 and
8:00 ^a.m. The VVH corresponds to the inverse of the contact time expressed in hours and is defined by the ratio of the volume flow rate of liquid hydrocarbon feedstock to the volume of catalyst loaded into the reaction unit implementing the hydrotreatment process according to the invention. . The reaction unit implementing the process for hydrotreating said diesel fraction according to the invention is preferably operated in a fixed bed, in a moving bed or in an ebullated bed, preferably in a fixed bed.

According to a second mode of use, said hydrotreating and/or hydrocracking process is a hydrotreating process (in particular hydrodesulphurization, hydrodenitrogenation, hydrogenation of aromatics) and/or hydrocracking of a vacuum distillate cut produced in the presence of at least one catalyst prepared according to the sulfurization process according to the invention. Said hydrotreating and/or hydrocracking process, otherwise called hydrocracking or hydrocracking pretreatment process, aims, depending on the case, at eliminating the sulfur, nitrogen or aromatic compounds present in said distillate cut so as to carry out a pretreatment before conversion in catalytic cracking or hydroconversion processes, or in hydrocracking the distillate cut which may have been pretreated beforehand if necessary.

A wide variety of feedstocks can be processed by the vacuum distillate hydrotreating and/or hydrocracking processes described above. Generally they contain at least 20% volume and often at least 80% volume of compounds boiling above 340° C. at atmospheric pressure. The feedstock can be, for example, vacuum distillates as well as feedstocks from aromatics extraction units from lubricating oil bases or from solvent dewaxing of lubricating oil bases, and/or deasphalted oils. , or else the filler can be a deasphalted oil or paraffins resulting from the Fischer-Tropsch process or even any mixture of the aforementioned fillers. In general, the fillers have a boiling point T5 greater than 340°C at atmospheric pressure, and better still greater than 370°C at atmospheric pressure, that is to say that 95% of the compounds present in the filler have a point boiling point higher than 340°C, and better still higher than 370°C. The nitrogen content of the feeds 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 feeds treated in the processes according to the invention is usually between 0.01 and 5.0% by weight. The filler may optionally contain metals (for example nickel and vanadium). The asphaltene content is generally less than 3000 ppm by weight.

The catalyst prepared according to the sulfurization process according to the invention is generally brought into contact, in the presence of hydrogen, with the fillers 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 greater than 1 MPa, often between 2 and 25 MPa, preferably between 3 and 20 MPa, the volumetric speed being between 0.1 and 20.0 h ^-1 and preferably 0.1-6.0 h ^-1 , preferably 0.2-3.0 h ^-1 , and the quantity of hydrogen introduced is such that the volume ratio liter of hydrogen/liter of hydrocarbon, expressed in volume of hydrogen, measured under normal conditions of temperature and pressure, per volume of liquid charge, is between 80 and 5,000 L/L and the 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, into products having boiling points below 340° C. at atmospheric pressure, and better still below 370° C. at atmospheric pressure, above to 15% and even more preferably between 20 and 95%.

The vacuum distillate hydrotreating and/or hydrocracking processes using the catalysts prepared according to the sulfurization process according to the invention cover the pressure and conversion ranges ranging from mild hydrocracking to high pressure hydrocracking. . By mild hydrocracking is meant hydrocracking leading to moderate conversions, generally less than 40%, and operating at low pressure, generally between 2 MPa and 6 MPa.

The catalyst prepared according to the sulfurization process according to the invention can be used alone, in a single or several fixed bed catalytic beds, in one or several reactors, in a so-called one-step hydrocracking scheme, with or without liquid recycling. of the unconverted fraction, or alternatively in a so-called two-stage hydrocracking scheme, optionally in combination with a hydrorefining catalyst located upstream of the catalyst prepared according to the sulfurization process according to the invention.

According to a third mode of use, said hydrotreating and/or hydrocracking process is advantageously implemented as pretreatment in a fluidized bed catalytic cracking process (or FCC process for Fluid Catalytic Cracking according to the English terminology) . The pretreatment operating conditions in terms of temperature range, pressure, hydrogen recycling rate, hourly volume rate are generally identical to those described above for the hydrotreatment and/or hydrocracking processes of vacuum distillates. The FCC process can be carried out in a conventional manner known to those skilled in the art under the appropriate cracking conditions in order to produce lower molecular weight hydrocarbon products. For example, a summary description of catalytic cracking can be found in ULLMANS ENCYCLOPEDIA OF INDUSTRIAL CHEMISTRY VOLUME A 18, 1991, pages 61 to 64.

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

Unlike other hydrotreating processes, the hydrotreating (in particular hydrodesulfurization) of gasolines must make it possible to respond to a double antagonistic constraint: ensuring deep hydrodesulfurization of gasolines and limiting the hydrogenation of the unsaturated compounds present in order to limit the loss of octane number.

The feed is generally a hydrocarbon cut having a distillation range of between 30 and 260°C. Preferably, this hydrocarbon cut is a cut of the gasoline type. Very preferably, the gasoline cut is an olefinic gasoline cut resulting for example from a catalytic cracking unit (Fluid Catalytic Cracking according to the Anglo-Saxon terminology).

The hydrotreating process consists in bringing the hydrocarbon cut into contact with the catalyst prepared according to the sulfurization process according to the invention and hydrogen under the following conditions: at a temperature between 200 and 400° C., from preferably between 230 and 330°C, at a total pressure between 1 and 3 MPa, preferably between 1.5 and 2.5 MPa, at an Hourly Volume Velocity (VVH), defined as being the load volume flow rate related 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 process for the hydrotreatment of gasolines can be carried out in one or more reactors in series of the fixed bed type or of the bubbling bed type. If the method is implemented by means of at least two reactors in series, it is possible to provide a device for removing H ₂ S from the effluent from the first hydrodesulphurization reactor before treating said effluent in the second hydrodesulfurization reactor.

The following examples demonstrate that the catalyst obtained according to the sulphurization process including a presulphurization step (step a) before the hydrothermal sulphurization step (step b) according to the invention makes it possible to observe catalytic activity in hydrotreatment and / or improved hydrocracking compared to a process with conventional sulfurization.

Examples

Example 1: Preparation of the NiMoP catalyst on C1 alumina containing an additive without steps a) and b) (not in accordance with the invention).

On an alumina support having a BET surface of 230 m ² /g, a pore volume obtained by mercury porosimetry of 0.78 ml/g and an average pore diameter of 11.5 nm defined as the median volume diameter by mercury porosimetry and which is in the "extruded" form, nickel, molybdenum and phosphorus are added. The impregnation solution is prepared by dissolving at 90°C molybdenum oxide (24.34 g) and nickel hydroxide (5.88 g) in 7.47 g of a phosphoric acid solution 85% in water and dilution in water to reach the desired metal content by dry impregnation. After dry impregnation, the extrudates are left to mature in an atmosphere saturated with water for 12 hours at ambient temperature, then they are dried at 90° C. for 16 hours.

Additive introduction step

In a closed chamber is placed a batch of 20 g of extrudates. 2 g of butyl lactate in liquid form are dispersed on the surface of the batch of extrudates at ambient temperature and pressure. The amount of butyl lactate is such that the molar ratio (butyl lactate)/Mo is 1 mol/mol. The closed enclosure is placed in an oven at 120° C. for 6 hours. 22 g of catalyst C1 impregnated with the organic compound are thus obtained. The final metal composition of catalyst C1, determined by X-ray fluorescence after calcination on a sample of catalyst C1 calcined at 550°C for analysis, is expressed as a weight percentage of metal oxides: MoO3 = 9.7 ± 0.1% by weight, NiO=1.9±0.1% by weight and P ₂ O ₅ =1.7±0.1% by weight. Catalyst C1 also has a (butyl lactate)/Mo molar ratio of 1 mol/mol.

Example 2: Preparation of the NiMoP catalyst on C2 alumina containing an additive with steps a) and b) according to the invention (in accordance with the invention).

Step a):

10 g of catalyst precursor C1 described above in Example 1 and which is in the "extruded" form are impregnated to dryness at room temperature with an aqueous solution containing 1.1 g of thioacetamide and whose volume is equal to the volume catalyst precursor C1. The amounts involved are such that the amount of thioacetamide is 2 moles per mole of molybdenum. The extrudates are dried at 50° C. under vacuum (P=20 mmHg or 0.003 MPa) for 30 minutes.

Step b) :

2.5 g of extrudates from step a) are immersed in 80 ml of an aqueous solution containing 1.1 ml of hydrochloric acid and having a pH of 1 which is heated to 85° C. under reflux. 7.6 g of thioacetamide are then added in four identical portions with a time interval of 15 minutes. The mixture is then maintained at 85° C. under reflux and with stirring for 2 hours. After cooling to ambient temperature, the extrudates are filtered, washed with water and then with ethanol before being dried at 50° C. under vacuum (P=20 mmHg or 0.003 MPa) for 30 minutes. The final metal composition of catalyst C2, determined by X-ray fluorescence after calcination on a sample of catalyst C2 calcined at 550°C for analysis, is expressed as a weight percentage of metal oxides: MoO3 = 9.7 ± 0.1% by weight , NiO=1.9±0.1% by weight and P ₂ O ₅ =1.7±0.1% by weight.

Example 3 : Evaluation in hydrogenation of toluene of catalysts C1 (not in accordance with the invention) and C2 (in accordance with the invention).

The hydrogenating activity (HYD) of the sulfur catalysts is evaluated in the presence of H ₂ S and under hydrogen pressure.

The same feed is used for the catalyst activation step for the evaluation of the catalytic activity:
- Toluene 20% by weight,
- Cyclohexane 74.12% by weight,
- DMDS (DiMethylDiSulphide) 5.88% by weight (3.8% by weight in S),

DMDS decomposes from 180° C. to form H ₂ S and thus allow sulfurization of C1 (not in accordance with the invention). DMDS is not necessary for catalyst C2 (in accordance with the invention). However, the DMDS is maintained in all cases because the catalytic test conditions must be the same for all the catalysts to allow their comparison.

The activation conditions are as follows:

The catalytic bed is crossed by the charge at VVH 4 h ^-1 under a flow of hydrogen such that the ratio of the volume flow rates H ₂ /charge is 450 NL/L at 6 MPa (60 bar) at a temperature following a ramp of 2°C/min up to 350°C, the temperature being maintained at 350°C for 5 hours.

The operating conditions for evaluating the catalytic activity in the hydrogenation of toluene are as follows:

The catalytic bed is traversed by the charge at VVH 2 h ^-1 under a flow of hydrogen such that the ratio of the volume flow rates H ₂ /charge is 450 NL/L at 6 MPa (60 bar) at 350°C.

The relative activity concentrations reported are calculated on the basis of an overall order of 1 for all the catalysts.

The percentage of toluene conversion (% HYD _toluene ) is calculated from the dosage of residual toluene determined by on-line analysis by gas phase chromatography and the hydrogenating activity (AH) corresponds to the considered kinetic constant of order 1 expressed in h ^-1 :

The catalytic performances of the catalysts tested are compared with catalyst C1 (not in accordance with the invention) in table 1 using the following formula:

Table 1 clearly shows the gain in the catalytic effect provided by the combination of steps a) and b) according to the invention since catalyst C2 has a gain in toluene hydrogenation activity compared to catalyst C1 having no not undergone steps a) and b). Since the organic compound and the quantity introduced are the same for catalysts C1 and C2, the gain in activity indeed comes from carrying out steps a) and b) according to the invention.

Catalyst
( comparative or according to the invention ) Catalyst preparation steps hydrogenating activity C1 (comp) Introduction of an organic compound without steps a) and b) 100 C2 (rev) Stage of introduction of an organic compound then stages a) and b) 121

Table 1: Activity relative to iso-volume in hydrogenation of catalysts C1 (not in accordance with the invention) and C2 (in accordance with the invention)

Claims (19)

Process for sulfurizing a catalyst comprising a porous support, at least one element from group VIB and/or at least one element from group VIII, and at least one organic compound, said process comprising the following steps:
a) a presulphurization stage comprising:
a1) a dry impregnation step at a temperature below 50°C of said catalyst, in which said catalyst is brought into contact with an impregnation solution comprising a sulfurizing agent,
a2) a step of drying at a temperature below 200° C. the catalyst obtained in step a1) to form a presulphurized catalyst,
b) then a sulfurization step comprising:
b1) an excess impregnation step at a temperature of between 50 and less than 200°C of said presulphurized catalyst, in which said catalyst is brought into contact with an acid impregnation solution comprising a sulphurizing agent,
b2) a step of drying at a temperature below 200° C. the catalyst obtained in step b1) to form a sulphide catalyst, Sulphidation process according to claim 1, in which the amount of sulphurizing agent added to the impregnating solution of step a1) is such that the molar ratio S/(group VIB and/or group VIII elements) is between 0.1 and 10. Sulfurization process according to one of the preceding claims, in which step a1) is carried out at ambient temperature. Sulfurization process according to one of the preceding claims, in which the solvent of the impregnation solution of step a1) is chosen from water or ethanol or a mixture of ethanol and water. Sulfurization process according to one of the preceding claims, in which the sulphurizing agent of stages a1) and b1) is chosen from thioacetamide, thioacetic acid and thiourea. Sulfurization process according to one of the preceding claims, in which the total quantity of sulphurizing agent added to the impregnation solution b1) is such that the ratio S/(elements of group VIB and/or of group VIII) is comprised between 1 and 200. Sulfurization process according to one of the preceding claims, in which the acid of the acid impregnation solution of step b1) is chosen from hydrochloric acid, sulfuric acid, sulfamic acid, formic, lactic acid and γ-ketovaleric acid. Sulphidation process according to one of the preceding claims, in which the solvent of the impregnation solution of step b1) is chosen from chosen from 2-(2-methoxyethoxy)ethanol, 2-(2-ethoxyethoxy) ethanol, 2-(2-butoxyethoxy)ethanol, 2-(2-hexyloxyethoxy)ethanol, triethylene glycol methyl ether, triethylene glycol ethyl ether, dipropylene glycol n-butyl ether, tripropylene glycol methyl ether, tripropylene glycol n-butyl ether and water, taken alone or in a mixture. Sulphidation process according to one of the preceding claims, which further comprises an activation step c) in which said sulfurized catalyst obtained in step b) is brought into contact with an inert gas stream at a temperature between 200 and 450°C or with a reducing gas flow at a temperature between 50 and 450°C. Sulfurization process according to the preceding claims, in which the activation step c) is carried out without addition of sulfurizing agent. Sulfurization process according to one of the preceding claims, in which the content of group VIB element is between 5 and 40% by weight, expressed as group VIB metal oxide relative to the total weight of the catalyst and the content of group VIB element VIII is between 1 and 10% by weight expressed as group VIII metal oxide relative to the total weight of the catalyst. Sulphidation process according to one of the preceding claims, in which the element from group VIB is chosen from molybdenum and tungsten, and the element from group VIII is chosen from cobalt and nickel. Sulfurization process according to one of the preceding claims, in which the organic compound is chosen from an organic compound containing oxygen and/or nitrogen and/or sulphur. Sulphidation process according to the preceding claim, in which the organic compound is chosen from a compound comprising one or more chemical functions chosen from a carboxylic, alcohol, thiol, thioether, sulphone, sulphoxide, ether, aldehyde, ketone, ester, carbonate, amine, nitrile, imide, oxime, urea, amide, or a compound including a furan ring or even a sugar. Sulfurization process according to the preceding claim, in which the organic compound is chosen from γ-valerolactone, 2-acetylbutyrolactone, triethylene glycol, diethylene glycol, ethylene glycol, ethylenediaminetetra-acetic acid (EDTA), maleic acid , malonic acid, citric acid, acetic acid, oxalic acid, malic acid, gluconic acid, glucose, fructose, sucrose, sorbitol, xylitol, γ acid -ketovaleric, a dialkyl C1-C4 succinate and more particularly dimethyl succinate, dimethylformamide, 1-methyl-2-pyrrolidinone, propylene carbonate, 2-methoxyethyl 3-oxobutanoate, bicine, tricine, 2-furaldehyde (also known as furfural), 5-hydroxymethylfurfural, 2-acetylfuran, 5-methyl-2-furaldehyde, ascorbic acid, butyl lactate, ethyl lactate, butyryllactate ethyl 3-hydroxybutanoate, ethyl 3-ethoxypropanoate, 2-ethyl acetate thoxyethyl, 2-butoxyethyl acetate, 2-hydroxyethyl acrylate, 1-vinyl-2-pyrrolidinone, 1,3-dimethyl-2-imidazolidinone, 1,5-pentanediol, 1-(2- hydroxyethyl)-2-pyrrolidinone, 1-(2-hydroxyethyl)-2,5-pyrrolidinedione, 5-methyl-2(3H)-furanone, 1-methyl-2-piperidinone, 4-aminobutanoic acid, butyl glycolate, ethyl 2-mercaptopropanoate, ethyl 4-oxopentanoate, diethyl maleate, dimethyl maleate, dimethyl fumarate, diethyl fumarate, dimethyl adipate and 3- dimethyl oxoglutarate, diethyl tartrate and diethyl malate. Sulphidation process according to one of the preceding claims, in which the catalyst also comprises phosphorus, the phosphorus content being between 0.1 and 20% by weight, expressed as P ₂ O ₅ relative to the total weight of the catalyst. Sulphidation process according to one of the preceding claims, in which the porous support is a support based on alumina or silica or silica-alumina. Catalyst obtained according to the sulfurization process according to one of Claims 1 to 17. Use of the catalyst prepared according to one of Claims 1 to 17 in a process for the hydrotreating and/or hydrocracking of hydrocarbon cuts.