阅读说明：本技术 使来自汽油加氢脱硫方法的未再生的失效的催化剂恢复活性的方法 (Process for reactivating non-regenerated spent catalyst from gasoline hydrodesulfurization process ) 是由 E·德韦尔 E·吉拉尔 P·勒弗莱夫 于 2019-12-10 设计创作，主要内容包括：本发明涉及使由加氢处理方法产生的至少部分失效的催化剂恢复活性的方法,所述至少部分失效的催化剂产生自新鲜催化剂,所述新鲜催化剂包含第VIIl族金属,第VIb族金属,氧化物载体和任选的磷,所述至少部分失效的催化剂还包含相对于该至少部分失效的催化剂的总重量的2重量％至20重量％的含量的碳和相对于该至少部分失效的催化剂的总重量的1重量％至8重量％的含量的硫,所述方法包括以下步骤：a)使所述失效的催化剂与包括含第VIb族金属的化合物的浸渍溶液接触,b)在低于200℃的温度下进行干燥步骤。(The invention relates to a method for reactivating an at least partially spent catalyst produced by a hydrotreating process, said at least partially spent catalyst being produced from a fresh catalyst comprising a group vil metal, a group VIb metal, an oxidic support and optionally phosphorus, said at least partially spent catalyst further comprising a content of carbon of from 2 to 20 wt% relative to the total weight of the at least partially spent catalyst and a content of sulphur of from 1 to 8 wt% relative to the total weight of the at least partially spent catalyst, said method comprising the steps of: a) contacting the spent catalyst with an impregnation solution comprising a group VIb metal containing compound, b) performing a drying step at a temperature below 200 ℃.)

1. A method of rejuvenating an at least partially spent catalyst produced by a hydrotreating process, the at least partially spent catalyst being produced from a fresh catalyst comprising at least one group vil metal, at least one group VIb metal, an oxidic support and optionally phosphorus, the at least partially spent catalyst further comprising carbon in an amount of from 2 wt% to 20 wt% relative to the total weight of the at least partially spent catalyst and sulphur in an amount of from 1 wt% to 8 wt% relative to the total weight of the at least partially spent catalyst, the method comprising the steps of:

a) contacting the at least partially spent catalyst with a impregnation solution comprising a group VIb metal containing compound,

b) the drying step is carried out at a temperature below 200 ℃ to obtain a catalyst with restored activity.

2. The process according to the preceding claim, wherein in step a) the molar ratio of the added group VIb metal relative to the group VIb metal already present in the at least partially spent catalyst is from 0.15 to 2.5 mol/mol.

3. The process according to any one of the preceding claims, wherein in step a) the impregnation solution further comprises a group VIII metal containing compound, the molar ratio of the added group VIII metal to the group VIII metal already present in the at least partially spent catalyst being in the range of from 0.1 to 2.5 mol/mol.

4. The method according to any one of the preceding claims, wherein in step a), the impregnation solution further comprises phosphorus; the molar ratio of phosphorus added to the group VIb metal already present in the at least partially spent catalyst is in the range of from 0.1 to 2.5 mol/mol.

5. The method according to any one of the preceding claims, wherein in step a) the impregnation solution further comprises an organic compound comprising oxygen and/or nitrogen and/or sulphur; the molar ratio of the added organic compound to the group VIb metal already present in the at least partially spent catalyst is in the range of from 0.01 to 5 mol/mol.

6. The process according to the preceding claim, wherein the organic compound containing oxygen and/or nitrogen and/or sulphur is selected from compounds containing one or more chemical functional groups selected from carboxylic acid, alcohol, thiol, thioether, sulfone, sulfoxide, ether, aldehyde, ketone, ester, carbonate, amine, nitrile, imide, oxime, urea or amide functional groups or compounds containing a furan ring or also sugars.

7. Process according to the preceding claim, in which the organic compound comprising oxygen and/or nitrogen and/or sulphur is chosen from gamma valerolactone, 2-acetylbutyrolactone, triethylene glycol, diethylene glycol,ethylene glycol, ethylene diamine tetraacetic acid, maleic acid, malonic acid, citric acid, gluconic acid, succinic acid di (C)₁-C₄Alkyl) esters, glucose, fructose, sucrose, sorbitol, xylitol, gamma-ketovaleric acid, dimethylformamide, 1-methyl-2-pyrrolidone, propylene carbonate, 2-methoxyethyl 3-oxobutyrate, N, N-dihydroxyethylglycine, tris (hydroxymethyl) methylglycine, 2-furfural, 5-hydroxymethylfurfural, 2-acetylfuran, 5-methyl-2-furfural, ascorbic acid, butyl lactate, ethyl 3-hydroxybutyrate, ethyl 3-ethoxypropionate, 2-ethoxyethyl acetate, 2-butoxyethyl acetate, 2-hydroxyethyl acrylate, 1-vinyl-2-pyrrolidone, 1, 3-dimethyl-2-imidazolidinone, 1- (2-hydroxyethyl) -2-pyrrolidone, 1- (2-hydroxyethyl) -2, 5-pyrrolidinedione, 5-methyl-2 (3H) -furanone, 1-methyl-2-piperidone, and 4-aminobutyric acid.

8. The method according to any one of the preceding claims, wherein in step a) the impregnation solution comprises a water-ethanol or water-methanol mixture.

9. The process according to any of the preceding claims, wherein the activity-restoring step a) is preceded by a de-oiling step comprising contacting the at least partially spent catalyst with a flow of inert gas at a temperature of from 300 ℃ to 400 ℃.

10. The process according to any of the preceding claims, wherein the fresh catalyst has a group VIb metal content of from 1 to 40 wt% of the group VIb metal oxide, relative to the total weight of the catalyst.

11. A process according to any one of the preceding claims, wherein the fresh catalyst has a content of group VIII metal of from 0.1 to 10% by weight of said group VIII metal oxide, relative to the total weight of the catalyst.

12. The method of any one of the preceding claims, which isIn a fresh catalyst having a content of P of 0.3 to 10% by weight relative to the total weight of the catalyst₂O₅Expressed as phosphorus content and a phosphorus/(group VIb metal) molar ratio in the catalyst of 0.1 to 0.7.

13. A process according to any one of the preceding claims, wherein the oxide support of the fresh catalyst is selected from alumina, silica-alumina, or alternatively, titanium or magnesium oxide, used alone or as a mixture with alumina or silica-alumina.

14. The process according to any one of the preceding claims, wherein the at least partially spent catalyst results from a process for the selective hydrodesulfurization of a gasoline fraction containing sulphur olefins.

15. A process for hydrodesulphurization of a gasoline fraction containing sulphur olefins, wherein the gasoline fraction, hydrogen and a catalyst for recovering the activity of the process according to any one of claims 1 to 14 are contacted, the hydrodesulphurization process being carried out at a temperature of from 200 ℃ to 400 ℃ and at a total pressure of from 1 to 3MPa for a period of from 1 to 10h^-1The hourly space velocity of (1) and a hydrogen/gasoline feed volume ratio of 100-.

16. Process according to the preceding claim, in which the reactivated catalyst is subjected to a sulfurization step before or during the hydrodesulphurization process.

17. Process according to any one of claims 15 and 16, carried out in a catalytic bed of a fixed bed type reactor comprising a plurality of catalytic beds; at least one other catalytic bed upstream or downstream of the catalytic bed containing the catalyst with restored activity, in the direction of circulation of the feed, contains at least partially fresh catalyst and/or regenerated catalyst.

18. The process according to any one of claims 15 to 17, carried out in at least two reactors of fixed bed type or ebullating bed type connected in series; at least one of the reactors contains a reactivated catalyst and the other reactor contains fresh catalyst or regenerated catalyst, or a mixture of reactivated catalyst and fresh and/or regenerated catalyst, in any order, with or without removal of at least a portion of the H from the effluent produced by the first reactor before it is treated in the second reactor₂S。

Technical Field

The present invention relates to a process for reactivating a catalyst used in a hydrotreating process and to the use of this reactivated catalyst in a process for the hydrodesulphurization of gasoline fractions.

Background

Sulfur is an element naturally present in crude oil and, therefore, is present in gasoline and gas oil if it is not removed during refining. However, sulfur in gasoline can interfere with the efficiency of the emission reduction system (catalytic converter) and cause air pollution. In order to combat environmental pollution, therefore, all countries are increasingly adopting strict sulfur regulations, such as 10ppm (by weight) of sulfur in gasoline sold in europe, china, the united states and japan. The problem of reducing the sulfur content focuses mainly on the gasoline obtained by cracking, whether catalytic (FCC, fluid catalytic cracking) or non-catalytic (coking, visbreaking, steam cracking), which is the main precursor of sulfur in the gasoline pool.

A solution for reducing the sulfur content, well known to the person skilled in the art, consists in hydrotreating (or hydrodesulphurizing) a hydrocarbon fraction, in particular a catalytically cracked gasoline, in the presence of hydrogen and a heterogeneous catalyst. However, this process shows the major drawback of causing a very significant reduction in octane number if the catalyst used is not sufficiently selective. This reduction in octane number is particularly associated with the hydrogenation of the olefins present in this type of gasoline, which is associated with hydrodesulfurization.

Unlike other hydrotreating processes, in particular those for gas-oil type feeds, the hydrodesulfurization of gasoline must therefore allow to cope with double conflicting constraints: ensuring deep hydrodesulphurisation of the gasoline and limiting the hydrogenation of the unsaturated compounds present.

The most widely used approach to solve the above dual problems consists in adopting the following methods: the sequence of unit steps thereof allows to maximize the hydrodesulfurization while limiting the hydrogenation of the olefins. Thus, the latest processes, such as the Prime G + (trademark) process, allow to desulfurize pyrolysis gasolines rich in olefins, while limiting the hydrogenation of the mono-olefins and therefore the loss of octane and the high hydrogen consumption resulting therefrom. Such a process is described, for example, in patent applications EP1077247 and EP 1174485.

Thus, the selectivity of the reaction (the ratio of hydrodesulfurization to olefin hydrogenation) required can be achieved in part due to the choice of process, but in all cases, the use of an inherently selective catalytic system is often a critical factor. Typically, the catalysts used for such applications are sulfide type catalysts containing group VIb elements (Cr, Mo, W) and group VIII elements (Fe, Ru, Os, Co, Rh, Ir, Pd, Ni, Pt).Thus, in patent US5985136 it is claimed that the surface concentration is 0.5 x 10^-4To 3X 10^-4g MoO₃/m²The catalyst of (a) allows to achieve a high hydrodesulphurisation selectivity (93% Hydrodesulphurisation (HDS) versus 33% olefin Hydrogenation (HOO)). Furthermore, according to patents US4140626 and US4774220, it may be advantageous to add dopants (alkali metals, alkaline earth metals) to the conventional sulphide phase (CoMoS) to limit hydrogenation of olefins. Also known in the prior art are documents US8637423 and EP1892039, which describe selective hydrodesulfurization catalysts.

During its use in the hydrotreatment of petroleum fractions, the hydrotreating catalyst undergoes a reduction in activity due to the deposition of coke and/or compounds based on sulphur or containing other hetero elements. Therefore, after a certain time, it needs to be replaced. In particular, increases in sulfur specifications for fuels result in increased frequency of catalyst replacement, which results in increased costs associated with the catalyst and an increase in the amount of spent catalyst.

To overcome these drawbacks, the regeneration (mild calcination) of the catalysts used for the hydrodesulphurization of middle distillates (gas oils) or waste residues is an economically and ecologically advantageous process, since it allows to reuse these catalysts in industrial plants, instead of landfilling or recovering them (recovering metals). However, the regenerated catalyst is generally less active than the starting solid.

In order to overcome the deficiency of the hydrodesulphurisation activity of the regenerated catalyst, an additional "rejuvenation" treatment may be carried out. The method of restoring activity consists in re-impregnating the regenerated catalyst with a solution containing a metal precursor in the presence of an organic or inorganic additive. These "rejuvenation" methods are well known to those skilled in the art in the field of middle distillates. Many patents, for example US7906447, US8722558, US7956000, US7820579 or CN102463127, thus provide different methods for restoring the activity of catalysts for carrying out the hydrotreatment of middle distillates. Document US2017/036202 describes an increase in activity in a gas oil hydrotreating process when a group VIb metal and phosphorus are added to the regenerated catalyst. Catalysts for the hydrodesulfurization of middle distillates, which have a high metal content compared with catalysts for the selective hydrodesulfurization of gasoline, undergo significant sintering during use and regeneration. Therefore, the reactivation treatment is focused on the dissolution and redistribution of the metallic phase in order to recover a dispersion close to the fresh catalyst and thus obtain an activity close to the fresh catalyst. Current methods for restoring activity of hydrotreating catalysts have been developed only for restoring the hydrodesulfurization activity of catalysts used for the hydrodesulfurization of middle distillates and generally use a regeneration step before "restoring activity" in the strict sense.

Catalysts for selective hydrodesulfurization of gasoline have different problems of recovery activity than catalysts for hydrotreating of gas oils, in particular due to the need to maintain the selectivity of the catalyst in terms of olefin hydrodesulfurization and hydrogenation reactions. This is because the improvement of selectivity is more desirable than the increase or maintenance of activity in the gasoline field. Therefore, there is a great benefit to develop a specific method of restoring activity to catalysts for the selective hydrodesulfurization of gasoline.

In order to provide a simple process for desulphurizing olefinic gasolines while using spent hydroprocessing catalysts, US5423975 proposes the use of spent catalysts for residue hydroprocessing, which may be contaminated with metals such as nickel and vanadium. Such catalysts are neither regenerated nor reactivated. However, although this solution appears economically attractive, it may suffer from the problem of heterogeneity of the spent catalyst for residue hydrotreatment, whose coke or contaminant (metal or other contaminant) content may vary greatly, which may lead to strong variations in the performance of the catalyst for gasoline selective hydrodesulfurization.

Document EP1447436 describes a partially coked fresh catalyst which can be used in a process for the hydrodesulphurization of catalytically cracked gasolines.

This method of restoring activity is described in patent CN105642312 for spent catalysts used for the selective hydrodesulfurization of FCC gasoline. In addition to the organic reagent, this complex process uses one or more metal additives comprising at least one of the elements selected from the group consisting of Na, K, Mg, Ca, Cu and Zn; and heat treated under an atmosphere having a controlled oxygen content.

Therefore, today, there is a strong interest in the manufacturers and regeneration enterprises of catalysts and refineries for the recovery of the activity of hydrotreating catalysts, in particular catalysts for the hydrotreatment of gasoline cuts, which have catalytic performance qualities that remain unchanged in terms of hydrodesulfurization catalytic activity and/or selectivity and therefore allow the production of gasolines with low sulfur content without seriously reducing the octane number once they are used.

The present invention therefore relates to a "rejuvenation" process suitable for hydrotreating catalysts, with the aim of maintaining or minimizing the loss of hydrodesulphurisation activity and improving selectivity with respect to fresh catalyst.

Subject matter of the invention

The invention relates to a method for reactivating an at least partially spent catalyst produced by a hydrotreating process, said at least partially spent catalyst being produced from a fresh catalyst comprising at least one group vil metal, at least one group VIb metal, an oxidic support and optionally phosphorus, said at least partially spent catalyst further comprising carbon in a content ranging from 2% to 20% by weight relative to the total weight of the at least partially spent catalyst and sulphur in a content ranging from 1% to 8% by weight relative to the total weight of the at least partially spent catalyst, said method comprising the steps of:

a) contacting the at least partially spent catalyst with a impregnation solution comprising a group VIb metal containing compound,

b) the drying step is carried out at a temperature below 200 ℃ to obtain a catalyst with restored activity.

This is because it has been found that the method of restoring activity according to the invention allows to obtain a catalyst of restored activity that exhibits an acceptable catalytic activity, compared to the use of the same fresh catalyst, and surprisingly results in an improvement of the selectivity in a process for selective hydrodesulphurization of gasoline. Without being bound by any theory, it appears that the change in the active phase caused by restoring the activity of the at least partially spent catalyst leads to a better selectivity of the hydrodesulfurization reaction towards the active sites.

Unlike the known methods of restoring activity, the method according to the invention does not require a regeneration step before step a). The regeneration step is understood to mean a thermal treatment carried out in a gas stream comprising oxygen, generally air, at a temperature of between 350 ℃ and 550 ℃, preferably between 360 ℃ and 500 ℃. Thus, an at least partially spent catalyst is a catalyst that has not undergone a regeneration step after its use in a hydroprocessing process. Thus, the reactivation step a) is carried out on at least partially used, not regenerated catalyst.

According to an alternative form, the molar ratio of the added group VIb metal relative to the group VIb metal already present in the at least partially spent catalyst is between 0.15 and 2.5 mol/mol.

According to an alternative form, in step a), the impregnation solution also comprises a compound containing a group VIII metal, the molar ratio of the added group VIII metal to the group VIII metal already present in the at least partially spent catalyst being between 0.1 and 2.5 mol/mol.

According to an alternative form, in step a), the impregnation solution also comprises phosphorus; the molar ratio of added phosphorus to group VIb metal already present in the at least partially spent catalyst is from 0.1 to 2.5 mol/mol.

According to an alternative form, in step a), the impregnation solution also comprises an organic compound comprising oxygen and/or nitrogen and/or sulphur; the molar ratio of the added organic compound to the group VIb metal already present in the at least partially spent catalyst is in the range of from 0.01 to 5 mol/mol.

According to an alternative form, the organic compound containing oxygen and/or nitrogen and/or sulphur is chosen from compounds comprising one or more chemical functions chosen from carboxylic acid functions, alcohols, thiols, thioethers, sulfones, sulfoxides, ethers, aldehydes, ketones, esters, carbonates, amines, nitriles, imides, oximes, ureas or amide functions, or compounds or sugars comprising a furan ring.

According to an alternative form, the organic compound comprising oxygen and/or nitrogen and/or sulphur is selected from gamma-valerolactone, 2-acetylbutyrolactone, triethylene glycol, diethylene glycol, ethylene glycol, ethylenediamine tetraacetic acid, maleic acid, malonic acid, citric acid, gluconic acid, di (C1-C4 alkyl) succinate, glucose, fructose, sucrose, sorbitol, xylitol, gamma-ketovaleric acid, dimethylformamide, 1-methyl-2-pyrrolidone, propylene carbonate, 2-methoxyethyl 3-oxobutyrate, N, N-dihydroxyethylglycine, tris (hydroxymethyl) methylglycine, 2-furfural, 5-hydroxymethylfurfural, 2-acetylfuran, 5-methyl-2-furfural, ascorbic acid, butyl lactate, ethyl 3-hydroxybutyrate, ethyl 3-ethoxypropionate, 2-ethoxyethyl acetate, 2-butoxyethyl acetate, 2-hydroxyethyl acrylate, 1-vinyl-2-pyrrolidone, 1, 3-dimethyl-2-imidazolidinone, 1- (2-hydroxyethyl) -2-pyrrolidone, 1- (2-hydroxyethyl) -2, 5-pyrrolidinedione, 5-methyl-2 (3H) -furanone, 1-methyl-2-piperidone and 4-aminobutyric acid.

According to an alternative form, in step a), the impregnation solution comprises a water-ethanol or water-methanol mixture.

According to an alternative form, the step of recovering activity a) is preceded by a step of deoiling which comprises contacting the at least partially spent catalyst with a flow of inert gas at a temperature of between 300 ℃ and 400 ℃.

According to an alternative form, the content of group VIb metal of the fresh catalyst is from 1% to 40% by weight of oxide of group VIb metal, relative to the total weight of the catalyst.

According to an alternative form, the fresh catalyst has a content of group VIII metal ranging from 0.1% to 10% by weight of oxide of said group VIII metal, relative to the total weight of the catalyst.

According to an alternative form, the phosphorus content of the fresh catalyst, expressed as P2O5, is between 0.3% and 10% by weight relative to the total weight of the catalyst, and the phosphorus/(group VIb metal) molar ratio in the catalyst is between 0.1 and 0.7.

According to one alternative, the oxide support of the fresh catalyst is chosen from alumina, silica-alumina, or titanium or magnesium oxide, used alone or as a mixture with alumina or silica-alumina.

According to an alternative form, the at least partially spent catalyst results from a process for the selective hydrodesulfurization of a sulfur-containing olefinic gasoline fraction.

The invention also relates to a process for the hydrodesulphurization of a gasoline fraction containing sulphur olefins, in which the gasoline fraction, hydrogen and a catalyst whose activity is restored according to the process of the invention are brought into contact, the hydrodesulphurization process being carried out at a temperature of from 200 ℃ to 400 ℃ and at a total pressure of from 1 to 3MPa and at an hourly space velocity (defined as the feed volume flow rate with respect to the volume of the catalyst) of from 1 to 10h^-1And the volume ratio of hydrogen/gasoline feed was 100-1200 Sl/l.

According to one alternative, the reactivated catalyst is subjected to a sulfurization step before or during the hydrodesulphurization process.

According to an alternative form, the hydrodesulfurization process is carried out in a catalytic bed of a reactor of the fixed-bed type comprising a plurality of catalytic beds; at least one other catalytic bed upstream or downstream of the catalytic bed containing the catalyst with restored activity, in the feed circulation direction, contains at least partially fresh catalyst and/or regenerated catalyst.

According to an alternative form, the hydrodesulfurization process is carried out in at least two reactors of the fixed bed type or of the ebullating bed type, connected in series; at least one of the reactors contains a reactivated catalyst and the other reactor contains fresh catalyst or regenerated catalyst, or a mixture of reactivated catalyst and fresh and/or regenerated catalyst, in any order, with or without removal of at least a portion of the H from the effluent produced from the first reactor prior to treatment of the effluent in the second reactor₂S。

Subsequently, the family of chemical elements is given according to the CAS classification (CRC Handbook of Chemistry and Physics, CRC Press, ed. R.Lide, 81 th edition, 2000-. For example, group VIII according to the CAS classification corresponds to the metals in columns 8, 9 and 10 according to the new IUPAC classification.

Description of the invention

The reactivated catalyst obtained by the process according to the invention is produced from an at least partially spent catalyst, which is itself produced from a fresh catalyst that has been used for a certain time in the hydroprocessing process and that shows a significantly lower activity than the fresh catalyst, which needs to be replaced.

The at least partially spent catalyst may be produced from the hydrotreating of any petroleum fraction such as naphtha, kerosene, gas oil, vacuum distillate or residue fractions. Hydrotreating is understood to mean reactions which include, in particular, Hydrodesulfurization (HDS), Hydrodenitrogenation (HDN) and hydrogenation of aromatic compounds (HOA). It may also result from the hydroprocessing of biomass or bio-oil.

Preferably, the at least partially spent catalyst results from a process for the hydrodesulfurization of sulfur-containing olefinic gasoline fractions which is carried out under conditions as described below.

Fresh catalyst used in the hydroprocessing process is known to those skilled in the art. It comprises at least one group VIIl metal, at least one group VIb metal, an oxide support and optionally phosphorus and/or an organic compound. According to another alternative form, the fresh catalyst does not comprise phosphorus.

The preparation of fresh catalyst is known and generally comprises: the step of impregnating the metals of groups VIII and VIb, and optionally phosphorus and/or organic compounds, on an oxide support, followed by a drying operation, and then by an optional calcination makes it possible to obtain the active phase in its oxide form. Before the fresh catalyst is used in a process for the hydrodesulphurization of olefinic gasoline cuts containing sulphur, it is generally sulphided to form an active mass as described below.

According to an alternative form of the invention, the fresh catalyst has not been calcined during its preparation, that is to say the impregnated catalyst precursor has not been subjected to a heat treatment step at a temperature higher than 200 ℃, in an inert atmosphere or in an oxygen-containing atmosphere, in the presence or absence of water.

According to another alternative form of the invention, the fresh catalyst is subjected to a calcination step during its preparation, that is to say the impregnated catalyst precursor has been subjected to a heat treatment step at a temperature of from 200 ℃ to 1000 ℃, preferably from 250 ℃ to 750 ℃, typically during a period of from 15 minutes to 10 hours, in an inert atmosphere or an oxygen-containing atmosphere, in the presence or absence of water.

The group VIb metal present in the active phase of the fresh catalyst is preferably selected from molybdenum and tungsten. The group VIII metal present in the active phase of the fresh catalyst is preferably selected from cobalt, nickel and mixtures of these two elements. The active phase of the fresh catalyst is preferably selected from the elemental combinations nickel-molybdenum, cobalt-molybdenum and nickel-cobalt-molybdenum, very preferably the active phase consists of cobalt and molybdenum.

The content of group VIII metal is from 0.1 to 10% by weight, preferably from 0.6 to 8% by weight, preferably from 2 to 7% by weight, very preferably from 2 to 6% by weight, more preferably from 2.5 to 6% by weight, of oxide of group VIII metal, relative to the total weight of the fresh catalyst.

The content of group VIb metal is from 1 to 40% by weight, preferably from 1 to 25% by weight, very preferably from 2 to 18% by weight, of oxide of group VIb metal, relative to the total weight of the fresh catalyst.

The molar ratio of group VIII metal to group VIb metal of the at least partially spent catalyst is generally from 0.1 to 0.8, preferably from 0.2 to 0.6.

In addition, the fresh catalyst has a density of group VIb metal (expressed as the number of atoms of the metal per unit area of the catalyst) of from 0.5 to 30 group VIb metal atoms/nm²Preferably 2 to 25, more preferably 3 to 15 catalysts. Density of group VIb metal, which is expressed as the number of atoms of group VIb metal per unit area of catalyst (number of atoms of group VIb metal/nm)²Catalyst), for example, according to the following relationship:

wherein:

x = weight% of group VIb metal;

• N_A= avocado constant, equal to 6.022 × 10²³；

S = specific surface area of catalyst (m/g), measured according to standard ASTM D3663;

• M_M= group VIb metal molar mass (e.g. 95.94g/mol for molybdenum).

For example, if the catalyst comprises 20% by weight of molybdenum oxide MoO₃(i.e., 13.33 wt% Mo) and having a specific surface area of 100 m/g, then density d (Mo) is equal to:

。

optionally, the fresh catalyst may additionally have a phosphorus content of typically 0.3 to 10% by weight of P, relative to the total weight of the fresh catalyst₂O₅Preferably from 0.5 to 5% by weight, very preferably from 1 to 3% by weight, of P₂O₅. For example, the phosphorus present in the fresh catalyst is bound in the form of a heteropolyanion to the group VIb metal and optionally also to the group VIII metal.

Further, when phosphorus is present, the molar ratio of phosphorus/(group VIb metal) is usually 0.1 to 0.7.

Preferably, the fresh catalyst is characterized by 5 to 400m²A/g, preferably from 10 to 250m²A/g, preferably from 20 to 200m²G, very preferably from 30 to 180m²Specific surface area in g. In the present invention, the specific surface area is determined by the BET method according to ASTM D3663, as described in Rouquerol F., Rouquerol J. and Singh KAdsorption by Powders & Porous Solids: Principle, Methodology and ApplicationsAcademic Press, 1999, e.g., by Micromeritics^TMBrand Autopore III^TMThe assay was performed in a model apparatus.

The pore volume of the fresh catalyst is generally 0.4cm³G to 1.3cm³In g, preferably 0.6cm³G to 1.1cm³(ii) in terms of/g. As described in that same work, the total pore volume is measured by mercury porosimetry according to the ASTM D4284 standard, with a wetting angle of 140 °.

The Tapped Bulk Density (TBD) of the fresh catalyst is generally in the range from 0.4 to 0.7g/ml, preferably from 0.45 to 0.69 g/ml. The measurement of the TBD consists in introducing the catalyst into a graduated cylinder, the volume of which has been predetermined, and then knocking it by vibration until a constant volume is obtained. The bulk density of the knocked product is calculated by comparing the mass introduced with the volume occupied by the knocked product.

The fresh catalyst may be in the form of a cylindrical or multilobal (trilobal, quadralobal, etc.) extrudate or a sphere having a small diameter.

The oxidic support of the fresh catalyst is typically a porous solid selected from: alumina, silica-alumina and titania and magnesia, used alone or as a mixture with alumina or silica-alumina. It is preferably selected from the group consisting of silica, transition alumina and silica-alumina species; very preferably, the oxide support consists essentially of at least one transition alumina, that is to say it comprises at least 51% by weight, preferably at least 60% by weight, very preferably at least 80% by weight, even at least 90% by weight of transition alumina. It preferably consists only of transition alumina. Preferably, the oxidic support of the fresh catalyst is a "high temperature" transition alumina, that is to say, it comprises theta-, delta-, kappa-or alpha-phase alumina, alone or in a mixture, and gamma-, chi-or eta-phase alumina in an amount of less than 20%.

The fresh catalyst may additionally comprise at least one organic compound containing oxygen and/or nitrogen and/or sulphur before the sulphidation. Such additives are described later.

During the hydrotreating process, coke and sulfur, as well as other contaminants produced from the feed, such as silicon, arsenic or chlorine, form and/or deposit on the catalyst and convert fresh catalyst into at least partially spent catalyst.

Thus, an at least partially spent catalyst is composed of the oxidic support and the active phase (formed from at least one group VIb metal and at least one group VIII metal) resulting from the fresh catalyst, and optionally phosphorus, as well as carbon, sulfur and optionally other contaminants (such as silicon, arsenic and chlorine) resulting from the feed.

In fresh, at least partially spent or reactivated catalysts, the content of group VIb metals, group VIII metals and phosphorus was expressed as oxides after correcting for the loss on ignition of the catalyst sample (550 ℃ for 2 hours in a muffle furnace). Loss on ignition results from the loss of moisture, carbon, sulfur and/or other contaminants. It was determined according to ASTM D7348.

In an at least partially spent catalyst, the content of group VIb metal, group VIII metal and optionally phosphorus is essentially the same as the content of the fresh catalyst from which it was produced.

An at least partially spent catalyst is understood to mean a catalyst discharged from a hydrotreating process and preferably from a process for the hydrodesulphurization of sulphur-containing olefinic gasoline cuts carried out under conditions in which the catalyst has not undergone regeneration, i.e. thermal treatment at a temperature greater than 200 ℃ under a gas comprising air or oxygen. It may have undergone de-oiling.

It should be noted that the term "coke" or "carbon" in the present patent application denotes a hydrocarbon-based substance which is deposited on the catalyst surface during use of the catalyst, which is highly cyclized and concentrated and has an appearance similar to graphite.

The at least partially spent catalyst comprises in particular carbon in a content generally greater than or equal to 2% by weight, preferably ranging from 2% to 25% by weight and more preferably ranging from 5% to 16% by weight, with respect to the total weight of the at least partially spent catalyst. The carbon content was measured by elemental analysis according to ASTM D5373.

The at least partially spent catalyst comprises sulphur (prior to optional sulphiding) in an amount of from 1 to 8 wt%, preferably from 1 to 6 wt%, particularly preferably from 2 to 5 wt%, relative to the total weight of the at least partially spent catalyst. The residual sulfur content in the regenerated hydrotreating catalyst was measured by elemental analysis according to ASTM D5373.

Optionally, the at least partially spent catalyst may additionally exhibit a low content of contaminants, such as silicon, arsenic or chlorine, resulting from the feed treated by the fresh catalyst from which the at least partially spent catalyst was produced.

Preferably, the content of silicon (apart from silicon possibly present on fresh catalyst) is less than 2% by weight, very preferably less than 1% by weight, relative to the total weight of the at least partially spent catalyst.

The arsenic content is preferably less than 2000ppm by weight, very preferably less than 500ppm by weight, relative to the total weight of the at least partially spent catalyst.

The chlorine content is preferably less than 2000ppm by weight, very preferably less than 500ppm by weight, relative to the total weight of the at least partially spent catalyst.

Deoiling (optional step)

Preferably there is a de-oiling step prior to the reactivation step a). The de-oiling step typically comprises contacting the at least partially spent catalyst with a stream of inert gas (i.e. substantially free of oxygen), for example in a nitrogen atmosphere or the like, at a temperature of from 300 ℃ to 400 ℃, preferably from 300 ℃ to 350 ℃. Inert gas flow rate (in terms of flow rate per unit volume of catalyst) of 5 to 150S 1.1^{- 1}.h^-1For 3 to 7 hours.

In an alternative form, the deoiling step may be carried out by light hydrocarbons, by steam treatment or any other similar method.

The de-oiling step allows the removal of soluble hydrocarbons and thus releases the porosity of the at least partially spent catalyst required for restoring activity.

Restoration of Activity (step a)

After the optional deoiling step, the method for restoring activity according to the present invention comprises a restoring activity step a) according to which the at least partially spent catalyst is contacted with a impregnation solution comprising a compound comprising a group VIb metal.

Preferably, the molar ratio of the group VIb metal added to the group VIb metal already present in the at least partially spent catalyst is from 0.15 to 2.5mol/mol, preferably from 0.2 to 2.0mol/mol, still more preferably from 0.3 to 1.0 mol/mol.

This is because, during use of the catalyst in a hydroprocessing process, the pores of the catalyst become blocked with the passage of time and the active phase containing the metal becomes increasingly difficult to access. Thus, a decrease in catalytic activity is observed. In order to overcome the deficiency in hydrodesulphurisation activity of at least partially spent catalysts, the catalyst may be re-impregnated with a solution comprising a group VIb metal containing compound and optionally also a group VIII metal containing compound and/or phosphorus, in order to limit the activity drop and surprisingly increase the selectivity.

According to a first alternative, the reactivating step a) may also comprise contacting the at least partially spent catalyst with a impregnation solution containing, in addition to the compound of the metal of group VIb, a compound of a metal of group VIII.

In this case, the molar ratio of the group VIII metal already present in the at least partially spent catalyst relative to the group VIII metal is from 0.1 to 2.5mol/mol, preferably from 0.1 to 2.0mol/mol, and more preferably from 0.1 to 1.0 mol/mol.

According to a preferred alternative of this first alternative, the impregnation solution comprises, in addition to the solvent, only a compound containing a metal of group VIb and a compound containing a metal of group VIII.

The group VIb metal introduced is preferably selected from molybdenum and tungsten. The group VIII metal introduced is preferably selected from cobalt, nickel and mixtures of these two elements. Preferably, the elements nickel-molybdenum, cobalt-molybdenum and nickel-cobalt-molybdenum are selected in combination, and very preferably, the cobalt-molybdenum combination is selected.

For example, in a molybdenum source, an oxide and hydrogen may be usedOxides, molybdic acid and salts thereof, especially ammonium salts, e.g. ammonium molybdate, ammonium heptamolybdate, phosphomolybdic acid (H)₃PMo₁₂O₄₀) And their salts, and optionally silicomolybdic acid (H)₄SiMo₁₂O₄₀) And salts thereof. The molybdenum source may also be any heteropoly compound such as Keggin, absent Keggin, substituted Keggin, Dawson, Anderson or Strandberg types. Molybdenum trioxide and Keggin, absent Keggin (lacunary Keggin), substituted Keggin and Strandberg-type heteropoly compounds are preferably used.

Tungsten precursors that can be used are also well known to those skilled in the art. For example, in tungsten sources, oxides and hydroxides, tungstic acid and salts thereof, in particular ammonium salts, such as ammonium tungstate, ammonium metatungstate, phosphotungstic acid and salts thereof, and optionally silicotungstic acid (H)₄SiW₁₂O₄₀) And salts thereof. The tungsten source may also be any heteropoly compound such as Keggin, absent Keggin, substituted Keggin or Dawson type. Preferably, oxides and ammonium salts are used, such as ammonium metatungstate or Keggin, and hetero-polyanions of the Keggin-deficient or substituted Keggin type.

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

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

Any of the impregnation solutions described in the present invention may comprise any polar protic solvent known to those skilled in the art. Preferably, a polar protic solvent is used, for example selected from: methanol, ethanol and water. Preferably, the impregnation solution comprises a water-ethanol or water-methanol mixture as solvent to facilitate impregnation of the group VIb metal containing compound (and optionally the group VIII metal containing compound and/or the phosphorus containing compound and/or the organic compound) onto the at least partially spent catalyst containing coke (and thus partially hydrophobic). Preferably, the solvent used in the impregnation solution consists of a water-ethanol or water-methanol mixture.

According to a second alternative, the reactivation step a) may also comprise contacting the at least partially spent catalyst with an impregnation solution also containing phosphorus (in addition to the compound comprising the group VIb metal and optionally the compound comprising the group VIII metal).

In this case, the molar ratio of phosphorus added to the group VIb metal already present in the at least partially spent catalyst is in the range of from 0.1 to 2.5mol/mol, preferably in the range of from 0.1 to 2.0mol/mol, more preferably in the range of from 0.1 to 1.0 mol/mol.

According to a preferred alternative of this second alternative, the impregnation solution, apart from the solvent, comprises only the compound containing the metal of group VIb and the compound containing the metal of group VIII and phosphorus, preferably in the form of phosphoric acid.

The preferred phosphorus precursor is orthophosphoric acid H₃PO₄However, salts and esters thereof, such as ammonium phosphate, are also suitable. Phosphorus may also be introduced simultaneously with the group VIb element, which is Keggin, vacancy Keggin, substituted Keggin or Strandberg-type heteropolyanion forms.

The step a) of contacting the at least partially spent and optionally deoiled catalyst with a impregnation solution comprising a group VIb metal containing compound and optionally a group VIII metal containing compound and/or phosphorus may be performed by slurry impregnation, or by excess impregnation, or by dry impregnation, or by any other means known to the person skilled in the art.

Equilibrium (or excess) impregnation consists in immersing the support or catalyst in a volume of solution greater (usually significantly greater) than the pore volume of the support or catalyst, while keeping the system stirred, to improve the exchange between the solution and the support or catalyst. After the diffusion of the different substances into the pores of the support or catalyst, an equilibrium is finally reached. The amount of deposited element is controlled by pre-measuring the sorption isotherm that relates the concentration of the element to be deposited contained in the solution to the amount of element deposited on the solid at equilibrium of the solution.

Dry impregnation consists, in so far as it is concerned, in introducing an impregnation solution whose volume is equal to the pore volume of the support or catalyst. Dry impregnation allows all the metals and additives contained in the impregnation solution to be deposited on a given support or catalyst.

Step a) can advantageously be carried out using the impregnation solution by one or more excess solution impregnations or preferably by one or more dry impregnations and very preferably by a single dry impregnation of the at least partially spent catalyst.

According to a third alternative, the reactivation step a) may also comprise contacting the at least partially spent catalyst with an impregnation solution further comprising an organic compound containing oxygen and/or nitrogen and/or sulphur, in addition to the compound containing the group VIb metal and optionally the compound containing the group VIII metal and/or phosphorus. The function of the additive or organic compound is to increase the catalytic activity compared to a catalyst without the additive. The organic compound is preferably impregnated on the catalyst after being dissolved in an aqueous solution or a non-aqueous solution.

In this case, the molar ratio of the organic compound added to the group VIb metal already present in the at least partially spent catalyst is from 0.01 to 5mol/mol, preferably from 0.05 to 3mol/mol, preferably from 0.05 to 2mol/mol and very preferably from 0.1 to 1.5 mol/mol.

When multiple organic compounds are present, different molar ratios apply to each organic compound present.

According to a preferred alternative of this third alternative, the impregnation solution comprises, in addition to the solvent, only the compound containing the metal of group VIb, the compound containing the metal of group VIII, phosphorus, preferably in the form of phosphoric acid, and an organic compound.

Typically, the organic compound is selected from compounds comprising one or more chemical functional groups selected from: carboxylic acid, alcohol, thiol, thioether, sulfone, sulfoxide, ether, aldehyde, ketone, ester, carbonate, amine, nitrile, imide, oxime, urea and amide functionalities.

The oxygen-containing organic compound may be selected from compounds comprising one or more chemical functional groups selected fromOne or more of: carboxylic acid, alcohol, ether, aldehyde, ketone, ester or carbonate functions, or alternatively a compound comprising a furan ring, or alternatively a sugar. For example, the oxygen-containing organic compound may be one or more selected from the following compounds: ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol (molecular weight 200 to 1500g/mol), propylene glycol, 2-butoxyethanol, 2- (2-butoxyethoxy) ethanol, 2- (2-methoxyethoxy) ethanol, triglyme, glycerol, acetophenone, 2, 4-pentanedione, pentanone, acetic acid, maleic acid, malic acid, malonic acid, oxalic acid, gluconic acid, tartaric acid, citric acid, gamma-ketovaleric acid, succinic acid bis (C)₁-C₄Alkyl) esters, more particularly dimethyl succinate, methyl acetoacetate, ethyl acetoacetate, 2-methoxyethyl 3-oxobutyrate, 2-methacryloyloxyethyl 3-oxobutyrate, dibenzofuran, crown ethers, phthalic acid, glucose, fructose, sucrose, sorbitol, xylitol, γ -valerolactone, 2-acetylbutyrolactone, propylene carbonate, 2-furfural (also known as furfural), 5-hydroxymethylfurfural (also known as 5- (hydroxymethyl) -2-furfural or 5-HMF), 2-acetylfuran, 5-methyl-2-furfural, methyl 2-furoate, furfuryl alcohol (also known as furfuryl alcohol), furfuryl acetate, ascorbic acid, butyl lactate, butyl butyryl lactate, ethyl 3-hydroxybutyrate, ethyl 3-ethoxypropionate, methyl 3-methoxypropionate, 2-ethoxyethyl acetate, 2-butoxyethyl acetate, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate and 5-methyl-2 (3H) -furanone.

The nitrogen-containing organic compound may be one or more selected from compounds comprising one or more chemical functional groups selected from amine or nitrile functional groups. For example, the nitrogen-containing organic compound may be one or more selected from the group consisting of ethylenediamine, diethylenetriamine, hexamethylenediamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, acetonitrile, octylamine, guanidine, and carbazole.

The oxygen-and nitrogen-containing organic compound may be one or more selected from compounds comprising one or more chemical functional groups selected from carboxylic acid, alcohol, ether, aldehyde, ketone, ester, carbonate, amine, nitrile, imide, amide, urea or oxime functional groups. For example, the oxygen and nitrogen containing organic compound may be one or more selected from the group consisting of: 1, 2-cyclohexanediaminetetraacetic acid, Monoethanolamine (MEA), 1-methyl-2-pyrrolidone, dimethylformamide, ethylenediaminetetraacetic acid (EDTA), alanine, glycine, nitrilotriacetic acid (NTA), N- (2-hydroxyethyl) ethylenediamine-N, N ', N' -triacetic acid (HEDTA), diethylenetriaminepentaacetic acid (DTPA), tetramethylurea, glutamic acid, dimethylglyoxime, N, N-dihydroxyethylglycine, tris (hydroxymethyl) methylglycine, 2-methoxyethyl cyanoacetate, 1-ethyl-2-pyrrolidone, 1-vinyl-2-pyrrolidone, 1, 3-dimethyl-2-imidazolidinone, 1- (2-hydroxyethyl) -2-pyrrolidone, 1- (2-hydroxyethyl)) -2, 5-pyrrolidinedione, 1-methyl-2-piperidone, 1-acetyl-2-azepin, 1-vinyl-2-azepin, and 4-aminobutyric acid.

The sulfur-containing organic compound may be one or more selected from compounds comprising one or more chemical functional groups selected from thiol, thioether, sulfone or sulfoxide functional groups. For example, the sulfur-containing organic compound may be one or more selected from thioglycolic acid, 2,2' -thiodiethanol, 2-hydroxy-4-methylthiobutanoic acid, a sulfone derivative of benzothiophene or a sulfoxide derivative of benzothiophene, methyl 3- (methylthio) propionate and ethyl 3- (methylthio) propionate.

Preferably, the organic compound comprises oxygen; preferably, it is selected from gamma-valerolactone, 2-acetylbutyrolactone, triethylene glycol, diethylene glycol, ethylene glycol, ethylenediamine tetraacetic acid (EDTA), maleic acid, malonic acid, citric acid, gluconic acid, dimethyl succinate, glucose, fructose, sucrose, sorbitol, xylitol, gamma-ketovaleric acid, dimethylformamide, 1-methyl-2-pyrrolidone, propylene carbonate, 2-methoxyethyl 3-oxobutyrate, N-dihydroxyethylglycine, tris (hydroxymethyl) methylglycine, 2-furfural (also known as furfural), 5-hydroxymethylfurfural (also known as (5- (hydroxymethyl) -2-furfural or 5-HMF), 2-acetylfuran, 5-methyl-2-furfural, ascorbic acid, butyl lactate, ethyl 3-hydroxybutyrate, ethyl 3-ethoxypropionate, 2-ethoxyethyl acetate, 2-butoxyethyl acetate, 2-hydroxyethyl acrylate, 1-vinyl-2-pyrrolidone, 1, 3-dimethyl-2-imidazolidinone, 1- (2-hydroxyethyl) -2-pyrrolidone, 1- (2-hydroxyethyl) -2, 5-pyrrolidinone, 5-methyl-2 (3H) -furanone, 1-methyl-2-piperidone and 4-aminobutyric acid.

The contacting step a) includes various embodiments. They differ in particular in the time when the organic compound is introduced when present and it can be carried out simultaneously with (co-impregnation) or after (post-impregnation) impregnation of the compound containing the metal of group VIb or before (pre-impregnation) it. In addition, the embodiments may be combined.

Advantageously, after each impregnation step, the impregnated support is matured. The maturation enables the impregnation solution to be uniformly dispersed within the carrier.

Any of the curing steps described in the present invention are advantageously carried out at atmospheric pressure, in a water-saturated atmosphere and at a temperature of 17 ℃ to 50 ℃, preferably at ambient temperature. In general, a maturation time of ten minutes to forty-eight hours, preferably thirty minutes to six hours, is sufficient.

Drying (step b)

According to the drying step b) of the method of restoring activity of the invention, the catalyst of restored activity obtained in step a) is subjected to a drying step at a temperature of less than 200 ℃, advantageously between 50 ℃ and 180 ℃, preferably between 70 ℃ and 150 ℃, very preferably between 75 ℃ and 130 ℃, without subsequent calcination.

The drying step is preferably carried out under an inert atmosphere or an oxygen-containing atmosphere.

The drying step may be carried out by any technique known to those skilled in the art. Advantageously, it is carried out at atmospheric pressure or under reduced pressure. Preferably, this step is carried out at atmospheric pressure. Advantageously, it is carried out in a transverse bed (diverted bed) using hot air or any other hot gas. Preferably, when the drying is carried out in a fixed bed, the gas used is air or an inert gas, such as argon or nitrogen. Very preferably, the drying is carried out in the presence of nitrogen and/or air in a transverse bed. Preferably, the duration of the drying step is from 5 minutes to 15 hours, preferably from 30 minutes to 12 hours.

According to a first alternative form, and advantageously, when an organic compound is present, drying is carried out so as to preferably maintain at least 30% by weight of the organic compound introduced during the impregnation step; preferably, the amount is greater than 50 wt%, more preferably greater than 70 wt%, calculated on the residual carbon on the reactivated catalyst.

The catalyst obtained from step b) is not subsequently calcined. Calcination is understood to mean a heat treatment at a temperature above 200 ℃ in a gas containing air or oxygen.

At the end of the drying step b), a catalyst is then obtained which regains activity and which is subjected to an optional activation (sulfidation) step in order to be subsequently used in the process for hydrodesulphurization of gasolines.

Vulcanization (optional step)

The reactivated catalyst of the process according to the invention is generally subjected to a sulfurization step before being brought into contact with the feed to be treated in the process for the hydrodesulphurization of gasolines. Sulfidation is preferably in a sulfur reducing medium, i.e. in H₂S and hydrogen to convert metal oxides to sulfides, such as, for example, MoS₂And Co₉S₈. Sulfidation is carried out by reacting a catalyst containing H in the presence of hydrogen₂S and hydrogen or can be decomposed to produce H₂A stream of sulfur compounds of S is injected onto the catalyst. Polysulfides, such as dimethyl disulfide (DMDS), are H commonly used in sulfide catalysts₂An S precursor. Sulfur may also be derived from the feed. Adjusting the temperature to make H₂S reacts with the metal oxide to form a metal sulfide. This sulfurization may be carried out in situ or ex situ (inside or outside the reactor) of the reactor of the process according to the invention at a temperature of from 200 ℃ to 600 ℃, more preferably from 300 ℃ to 500 ℃.

Hydrodesulfurization process

The invention also relates to a process for the hydrodesulphurization of gasoline fractions containing sulphur olefins, in which the gasoline fraction, hydrogen and the process according to the invention are recoveredActive catalyst contact, said hydrodesulfurization process being carried out at a temperature of from 200 ℃ to 400 ℃, preferably from 230 ℃ to 330 ℃, at a total pressure of from 1 to 3MPa, preferably from 1.5 to 2.5MPa, Hourly Space Velocity (HSV), defined as the feed volume flow rate relative to the catalyst volume, of from 1 to 10h^-1Preferably 2 to 6h^-1The hydrogen/gasoline feed volume ratio is between 100 and 1200 Sl/l, preferably between 150 and 400 Sl/l.

The hydrodesulphurization process according to the invention allows the conversion of organic sulphur compounds of the gasoline fraction into hydrogen sulphide (H)₂S) while limiting as much as possible the hydrogenation of the olefins present in said fraction.

Feed to be treated

The process according to the invention allows the treatment of any type of sulphur-containing olefinic gasoline fraction, such as, for example, fractions produced by coking, visbreaking, steam cracking or catalytic cracking (FCC, fluid catalytic cracking) units. Such gasoline may optionally consist of a significant portion of gasoline from other production processes or conversion processes (coker or steam cracked gasoline), such as atmospheric distillation (direct distillation produced gasoline (or straight run gasoline)). The feed preferably consists of a gasoline fraction produced by a catalytic cracking unit.

The feed is a sulphur-containing olefinic gasoline fraction, typically boiling in the range of from the boiling point of a (C2 or C3) hydrocarbon having 2 or 3 carbon atoms up to 260℃, preferably from the boiling point of a (C2 or C3) hydrocarbon having 2 or 3 carbon atoms up to 220℃, more preferably from the boiling point of a hydrocarbon having 5 carbon atoms up to 220℃. The process according to the invention can also treat feeds having lower endpoints than those mentioned above, such as, for example, C5-180 ℃ fractions.

The sulfur content of gasoline fractions produced by catalytic cracking (FCC) depends on the sulfur content of the feed treated by FCC, whether the FCC feed has been pretreated and the end point of the fractions. Generally, the sulfur content of the entire gasoline fraction, particularly those derived from FCC, is greater than 100ppm by weight, and in most times greater than 500ppm by weight. For gasoline with endpoints greater than 200 ℃, the sulfur content is typically greater than 1000ppm by weight; in some cases they may even reach values on the order of 4000 to 5000ppm by weight.

In addition, gasoline obtained from a catalytic cracking (FCC) unit contains on average 0.5 to 5 wt% dienes, 20 to 50 wt% olefins and 10 to 0.5 wt% sulfur, typically less than 300ppm mercaptans. Mercaptans are generally concentrated in the light fraction of gasoline, more specifically in the fraction with a boiling point of less than 120 ℃.

It should be noted that the sulfur compounds present in gasoline may also comprise heterocyclic sulfur compounds, such as, for example, thiophenes, alkylthiophenes or benzothiophenes. These heterocyclic compounds, unlike thiols, cannot be removed by extraction methods. These sulfur compounds are thus hydrotreated (resulting in their conversion to hydrocarbons and H)₂S) is removed.

Preferably, the gasoline treated by the process according to the invention is a heavy gasoline (or HCN, for "heavy cracked naphtha") resulting from a distillation step, the purpose of which is to separate a wide cut of gasoline (or FRCN, for "full range cracked naphtha") resulting from the cracking process into light gasoline (LCN, light cracked naphtha) and heavy gasoline HCN. The cut points for light and heavy gasolines are determined to limit the sulfur content of the light gasoline and to make it available for use in the gasoline pool, preferably without additional post-treatment. Advantageously, the wide FRCN fraction is subjected to a selective hydrogenation step as described below prior to the distillation step.

The hydrodesulfurization process can be carried out in one or more reactors of the fixed bed type or of the ebullating bed type, connected in series. If the process is carried out by means of at least two reactors connected in series, it is possible to provide a process for removing H from the effluent resulting from the first hydrodesulfurization reactor (before the treatment of said effluent in the second hydrodesulfurization reactor)₂And S.

The hydrodesulphurisation process according to the invention is carried out in the presence of a catalyst which restores activity. It can also be carried out in the presence of a mixture of reactivated catalyst and fresh or regenerated catalyst.

When present, the fresh or regenerated catalyst comprises at least one group VIIl metal, at least one group VIb metal and an oxide support, and optionally phosphorus and/or an organic compound as described above.

The active phase and support of the fresh or regenerated catalyst may be the same or different from the active phase and support of the reactivated catalyst.

The active phase and support of the fresh catalyst may be the same or different from the active phase and support of the reactivated catalyst.

When the hydrodesulphurization process is carried out in the presence of a catalyst with restored activity and of a fresh or regenerated catalyst, it can be carried out in a reactor of the fixed bed type comprising a plurality of catalytic beds.

In this case, and according to a first alternative, the catalytic bed containing fresh or regenerated catalyst may precede the catalytic bed containing the catalyst of restored activity, in the direction of circulation of the feed.

In this case, and according to a second alternative, the catalytic bed containing the catalyst with restored activity may precede the catalytic bed containing the fresh or regenerated catalyst, in the direction of circulation of the feed.

In this case, and according to a third alternative, the catalytic bed may comprise a mixture of reactivated catalyst and fresh catalyst and/or regenerated catalyst.

In these cases, the operating conditions are those described above. They are generally identical in the different catalytic beds except for the temperature, which generally increases in the catalytic beds as the hydrodesulfurization reaction exotherms.

When the hydrodesulfurization process is carried out in the presence of a reactivated catalyst and a fresh or reactivated catalyst in a plurality of reactors of the fixed bed type or of the ebullated bed type connected in series, one reactor may contain the reactivated catalyst and the other reactor may contain the fresh or regenerated catalyst, or a mixture of the reactivated catalyst and the fresh and/or reactivated catalyst, and in any order. Can provide a reaction product in the effluent from the first hydrodesulfurization reactorRemoving H prior to treating the effluent in the second hydrodesulfurization reactor₂And S. In these cases, the operating conditions are as described above and may be the same or different in different reactors.

Selective hydrogenation (optional step)

According to an alternative form, the gasoline fraction is subjected to a selective hydrogenation step before the hydrodesulphurization process according to the invention.

Preferably, the gasoline treated by the hydrodesulfurization process according to the invention is a heavy gasoline resulting from a distillation step aimed at separating the wide gasoline fraction resulting from the cracking process (or FRCN, for a full range cracked naphtha) into a light gasoline and a heavy gasoline.

Advantageously, the wide FRCN fraction is subjected to a selective hydrogenation step as described below prior to the distillation step.

The FRCN fraction is pretreated in the presence of hydrogen and a selective hydrogenation catalyst to at least partially hydrogenate the diolefins and to carry out a reaction for increasing the molecular weight of a portion of the mercaptan (RSH) compounds present in the feed (to form thioethers by reaction with olefins).

To this end, the broad FRCN fraction is fed to a selective hydrogenation catalytic reactor containing at least one fixed or moving catalyst bed for the selective hydrogenation of dienes and for increasing the molecular weight of mercaptans. The reactions for the selective hydrogenation of diolefins and for increasing the molecular weight of mercaptans are preferably carried out over a sulfided catalyst comprising at least one group VIII element and optionally at least one group VIb element and an oxidic support. The group VIII element is preferably selected from nickel and cobalt, especially nickel. When present, the group VIb element is preferably selected from molybdenum and tungsten, with molybdenum being highly preferred.

The oxide support of the catalyst is preferably selected from alumina, nickel aluminate, silica, silicon carbide or mixtures of these oxides. Preferably, alumina is used, and more preferably, high purity alumina is used. According to a preferred embodiment, the selective hydrogenation catalyst is charged with 1% to 12% oxygenThe nickel oxide (NiO form) comprises nickel and from 6% to 18% by weight of molybdenum oxide (MoO)₃Form) a weight content comprising molybdenum and a nickel/molybdenum molar ratio of between 0.3 and 2.5, wherein the metal is deposited on a support consisting of alumina and wherein the degree of sulphidation of the metal constituting the catalyst is greater than 50%.

During the optional selective hydrogenation step, the gasoline is contacted with the catalyst at a temperature of from 50 ℃ to 250 ℃, preferably from 80 ℃ to 220 ℃ and more preferably from 90 ℃ to 200 ℃, with a liquid air velocity (LHSV) of 0.5h^-1-20h^-1The liquid air velocity is given in units of liters of feed per liter of catalyst per hour (l/l.h). The pressure is from 0.4MPa to 5MPa, preferably from 0.6 to 4MPa, and still more preferably from 1 to 2 MPa. The optional selective hydrogenation step is typically used in the range of 2 to 100Sm³Hydrogen/m³Feed, preferably 3 to 30Sm³Hydrogen/m³H of feed₂The/gasoline feed ratio was carried out.

Examples

Example 1-preparation of freshly calcined CoMo catalyst A1 (comparative)

The support for catalyst A1 was a catalyst having a particle size of 140m²Specific surface area per gram, 1.0cm³Transition alumina in pore volume/g. Catalyst a1 was prepared by dry impregnation of the support with an aqueous solution of ammonium heptamolybdate and cobalt nitrate, the volume of the solution containing the metal precursor being strictly equal to the pore volume of the alumina support body. The concentration of the metal precursor in the aqueous solution is adjusted to obtain the desired weight percent of molybdenum and cobalt on the final catalyst. After dry impregnation on the support, the catalyst was aged in a chamber saturated with water for 1 hour 30 minutes, dried in an oven at 90 ℃ under air for 12 hours, and then calcined in air at 450 ℃ for 2 hours.

The fresh catalyst A1 obtained after calcination had a content of molybdenum (MoO) of 9.2% by weight₃Equivalent) and 2.5 wt% cobalt (CoO equivalent). The Co/Mo atomic ratio of the catalyst is 0.52, and the specific surface area is 124 m/g.

Example 2-preparation of catalyst A2 for restoration of Activity by addition of Co and Mo (according to the invention)

Fresh catalyst A1 was used to desulfurize catalytically cracked (FCC) gasoline, which was characterized as listed in Table 1. The reaction was carried out in a transverse bed type reactor at 270 ℃ for 900 hours under the following conditions: p =2MPa, HSV =4h^-1，H₂/HC =300 liters per liter of hydrocarbon feed. The catalyst was pretreated at 350 ℃ with a feed containing 4% by weight of sulfur in the form of DMDS (dimethyldisulfide) to sulfide the oxide phase. The reaction was carried out in an isothermal pilot reactor in an upward stream.

TABLE 1

S ppm	392
		Aromatic hydrocarbons wt.%	41.3
Paraffin wax wt%	27.2
		Cycloalkane wt%	11.0
Olefin wt%	20.5
		T5℃	62
T95℃	225

After completion of the hydrodesulfurization of the above-mentioned catalytically cracked (FCC) gasoline, the spent catalyst a1 was removed from the reactor. The spent catalyst a1 was subsequently washed with toluene in a Soxhlet extractor (Soxhlet) at 250 ℃ for 7 hours (deoiling). The residual carbon and sulfur contents were 2.6 wt% and 4.3 wt%, respectively.

Catalyst a2 was prepared by dry impregnation of spent catalyst a1 with an aqueous solution of ammonium heptamolybdate and cobalt nitrate, the volume of the solution containing the metal precursor being strictly equal to the pore volume of the bulk of the spent catalyst a 1. The concentration of the metal precursor in the aqueous solution is adjusted to obtain the desired weight percent of molybdenum and cobalt on the final catalyst. After dry impregnation on spent catalyst a1, catalyst a2 was aged for 1 hour 30 minutes in a chamber saturated with water and then dried in an oven at 90 ℃ for 12 hours in air.

The molybdenum content of the catalyst A2 obtained after drying was 13.8% by weight (MoO)₃Equivalent), a cobalt content of 3.6% by weight (CoO equivalent), a Co/Mo atomic ratio of 0.50, a specific surface area of 113m²(ii) in terms of/g. The molar ratio of the added group VIb metal relative to the group VIb metal already present in the spent catalyst A1 was 0.5 mol/mol.

Example 3-preparation of catalyst A3 for restoring Activity by addition of Co, Mo and P (according to the invention)

Fresh catalyst a1 was used to desulfurize catalytically cracked (FCC) gasoline and was characterized as set forth in table 1. The reaction was carried out in a transverse bed reactor at 270 ℃ for 1400 hours under the following conditions: p =2MPa, HSV =4h^-1，H²/HC =300 liters per liter of hydrocarbon feed. The catalyst was pretreated at 350 ℃ with a feed containing 4% by weight of sulfur in the form of DMDS (dimethyldisulfide) to sulfide the oxide phase. The reaction takes place in an isothermal pilot reactor in an upward stream.

After the catalytic cracked (FCC) gasoline described in table 1 above was hydrodesulfurized, the spent catalyst a1 was removed from the reactor. The spent catalyst A1 was subsequently washed with toluene in a Soxhlet extractor (Soxhlet) at 250 ℃ for 7 hours. The residual carbon and sulfur contents were 3.0 wt.% and 4.2 wt.%, respectively. Its specific surface area is 120 m/g.

Catalyst A3 was prepared by dry impregnation of the spent catalyst a1 with an aqueous solution of molybdenum oxide, cobalt hydroxide and orthophosphoric acid, the volume of the solution containing the metal precursor being strictly equal to the pore volume of the spent catalyst a 1. The concentration of the metal precursor in the aqueous solution is adjusted to obtain the desired weight percentages of molybdenum, cobalt and phosphorus on the final catalyst. After dry impregnation on spent catalyst a1, catalyst A3 was aged for 1 hour 30 minutes in a chamber saturated with water and dried in an oven at 120 ℃ for 12 hours under air.

The catalyst A3 obtained after drying contained a content of 13.8% by weight of molybdenum (MoO)₃Equivalent), 3.6% by weight of cobalt (CoO equivalent) and 1.3% by weight of phosphorus (P)₂O₅Equivalent), the atomic ratio of Co/Mo was 0.50, the atomic ratio of P/Mo was 0.19, and the specific surface area was 110 m/g. The molar ratio of the added group VIb metal relative to the group VIb metal already present in the spent catalyst A1 was 0.5 mol/mol.

Example 4-preparation of catalyst for restoration of Activity by addition of Co, Mo, P and citric acid A4 (according to the invention)

Fresh catalyst a1 was used to desulfurize catalytically cracked (FCC) gasoline, the gasoline characteristics of which are listed in table 1. The reaction was carried out in a transverse bed reactor at 270 ℃ for 1600 hours under the following conditions: p =2MPa, HSV =4h^-1，H₂/HC =360 litres per litre of hydrocarbon feed. The catalyst was pretreated at 350 ℃ with a feed containing 4% by weight of sulfur in the form of DMDS (dimethyldisulfide) to sulfide the oxide phase. The reaction takes place in an isothermal pilot reactor in an upward stream.

After the catalytic cracked (FCC) gasoline described in table 1 above was hydrodesulfurized, the spent catalyst a1 was removed from the reactor. The spent catalyst A1 was subsequently washed with toluene in a Soxhlet extractor at 250 ℃ for 7 hours. The residual carbon and sulfur contents were 2.4 wt% and 4.2 wt%, respectively.

Catalyst a4 was prepared by dry impregnation of the spent catalyst a1 with an aqueous solution of molybdenum oxide, cobalt hydroxide, orthophosphoric acid and citric acid, the volume of the solution containing the metal precursor being strictly equal to the pore volume of the bulk of the spent catalyst a 1. The concentration of the metal precursor in the aqueous solution is adjusted to obtain the desired weight percentages of molybdenum, cobalt and phosphorus on the final catalyst. The molar ratio of citric acid to molybdenum on the final catalyst was 0.4. After dry impregnation on spent catalyst a1, catalyst a4 was aged for 1 hour 30 minutes in a chamber saturated with water and dried in an oven at 120 ℃ in air for 12 hours under air.

The catalyst A4 obtained after drying had a content of molybdenum (MoO3 eq.) of 18.5% by weight, cobalt (CoO eq.) of 4.5% by weight and phosphorus (P) of 1.3% by weight₂O₅Equivalent), the atomic ratio of Co/Mo was 0.47, the atomic ratio of P/Mo was 0.14, and the specific surface area was 103 m/g. The molar ratio of the added group VIb metal to the group VIb metal already present in the spent catalyst A1 was 1.0 mol/mol.

Example 5-preparation of freshly calcined CoMoP catalyst A5 (comparative)

The support of catalyst A5 was a transition alumina having a specific surface area of 140m²Per g, pore volume 1.0cm³(ii) in terms of/g. Catalyst a5 was prepared by dry impregnation of the support with an aqueous solution of molybdenum oxide, cobalt hydroxide and orthophosphoric acid, the volume of the solution containing the metal precursor being strictly equal to the pore volume of the alumina support body. The concentration of the metal precursor in the aqueous solution is adjusted to obtain the desired weight percentages of molybdenum, cobalt and phosphorus on the final catalyst. After dry impregnation on the support, the catalyst was aged in a chamber saturated with water for 1 hour 30 minutes, dried in an oven at 90 ℃ under air for 12 hours, and then calcined in air at 450 ℃ for 2 hours.

The fresh catalyst A5 obtained after calcination had a molybdenum (MoO) content of 10.3% by weight₃Equivalent), 2.0% by weight of cobalt (CoO equivalent) and 1.2% by weight of phosphorus (P)₂O₅Equivalent weight). The catalyst had an atomic ratio of Co/Mo of 0.37, an atomic ratio of P/Mo of 0.24 and a specific surface area of 121m²/g。

Example 6-preparation of catalyst A6 for restoration of Activity by addition of Co and Mo (according to the invention)

Fresh catalyst A5 for removing catalytically cracked (FCC) gasolineSulfur, the gasoline characteristics are listed in table 1. The reaction was carried out in a transverse bed reactor at 290 ℃ for 1500 hours under the following conditions: p =2MPa, HSV =4h^-1，H₂/HC =300 liters per liter of hydrocarbon feed. The catalyst was pretreated at 350 ℃ with a feed containing 4% by weight of sulfur in the form of DMDS (dimethyldisulfide) to sulfide the oxide phase. The reaction takes place in an isothermal pilot reactor in an upward stream.

After completion of the hydrodesulfurization of the above-mentioned catalytically cracked (FCC) gasoline, the spent catalyst a5 was removed from the reactor. The spent catalyst a5 was subsequently washed with toluene in a Soxhlet extractor (Soxhlet) at 250 ℃ for 7 hours. The residual carbon and sulfur contents were 5.7 wt% and 4.5 wt%, respectively.

Catalyst a6 was prepared by dry impregnation of the spent catalyst a5 with an aqueous solution of ammonium heptamolybdate and cobalt nitrate, the volume of the solution containing the metal precursor being strictly equal to the pore volume of the mass of the spent catalyst. The concentration of the metal precursor in the aqueous solution is adjusted to obtain the desired weight percent of molybdenum and cobalt on the final catalyst. After dry impregnation of the spent catalyst a5, catalyst a6 was aged for 1 hour 30 minutes in a chamber saturated with water and then dried in an oven at 90 ℃ for 12 hours under air.

The catalyst A6 obtained after drying had a molybdenum (MoO) content of 18.5% by weight₃Equivalent), 4.5% by weight of cobalt (CoO equivalent) and 1.2% by weight of phosphorus (P)₂O₅Equivalent), the atomic ratio Co/Mo is 0.47, the atomic ratio P/Mo is 0.13, and the specific surface area is 101 m/g. The molar ratio of the added group VIb metal to the group VIb metal already present in the spent catalyst A1 was 0.8 mol/mol.

Example 7-preparation of catalyst A7 for restoring Activity by addition of Co, Mo and P (according to the invention)

Fresh catalyst A5 was used to desulfurize catalytically cracked (FCC) gasoline, the characteristics of which are set forth in Table 1. The reaction was carried out in a transverse bed reactor at 270 ℃ for 1400 hours under the following conditions: p =2MPa, HSV =4h^-1，H₂/HC =300 liters per liter of hydrocarbon feed. The catalyst is heated to 350 DEG CThe oxide phase was sulfided by pretreatment with a feed containing 4 wt% of sulfur in the form of DMDS (dimethyldisulfide). The reaction takes place in an isothermal pilot reactor in an upward stream.

After the catalytic cracked (FCC) gasoline described in table 1 above was hydrodesulfurized, the spent catalyst a5 was removed from the reactor. The spent catalyst A5 was subsequently washed with toluene in a Soxhlet extractor at 250 ℃ for 7 hours. The residual carbon and sulfur contents were 3.0 wt.% and 4.2 wt.%, respectively. Its specific surface area is 120 m/g.

Catalyst a7 was prepared by dry impregnation of the spent catalyst a5 with an aqueous solution of molybdenum oxide, cobalt hydroxide and orthophosphoric acid, the volume of the solution containing the metal precursor being strictly equal to the pore volume of the bulk of the spent catalyst a 5. The concentration of the metal precursor in the aqueous solution is adjusted to obtain the desired weight percentages of molybdenum, cobalt and phosphorus on the final catalyst. After dry impregnation of the spent catalyst a5, catalyst a7 was aged for 1 hour 30 minutes in a chamber saturated with water and dried in an oven at 120 ℃ for 12 hours under air.

The catalyst A7 obtained after drying had a molybdenum (MoO) content of 15.3% by weight₃Equivalent), cobalt (CoO equivalent) in an amount of 3.4 wt% and phosphorus (P) in an amount of 2.5 wt%₂O₅Equivalent), the atomic ratio Co/Mo is 0.43, the atomic ratio P/Mo is 0.33, and the specific surface area is 104 m/g. The molar ratio of the added group VIb metal to the group VIb metal already present in the spent catalyst A5 was 0.5 mol/mol.

Example 8-preparation of Activity-restoring catalyst A8 by addition of Co, Mo, P and citric acid (according to the invention)

Fresh catalyst A5 was used to desulfurize catalytically cracked (FCC) gasoline, the characteristics of which are set forth in Table 1. The reaction was carried out in a transverse bed reactor at 250 ℃ for 800 hours under the following conditions: p2 MPa, HSV 4h^-1，H₂HC 400 liters per liter of hydrocarbon feed. The catalyst was pretreated at 350 ℃ with a feed containing 4% by weight of sulfur in the form of DMDS (dimethyldisulfide) to sulfide the oxide phase. The reaction is isothermalThe reaction in the pilot reactor takes place in an upward stream.

After the catalytic cracked (FCC) gasoline described in table 1 above was hydrodesulfurized, the spent catalyst a5 was removed from the reactor. The spent catalyst A5 was subsequently washed with toluene in a Soxhlet extractor at 250 ℃ for 7 hours. The residual carbon and sulfur contents were 1.5 wt.% and 4.5 wt.%, respectively.

Catalyst A8 was prepared by dry impregnation of the spent catalyst a5 with an aqueous solution of molybdenum oxide, cobalt hydroxide, orthophosphoric acid and citric acid, the volume of the solution containing the metal precursor being strictly equal to the pore volume of the bulk of the spent catalyst a 5. The concentration of the metal precursor in the aqueous solution is adjusted to obtain the desired weight percentages of molybdenum, cobalt and phosphorus on the final catalyst. The molar ratio of citric acid to molybdenum on the final catalyst was 0.4. After dry impregnation of the spent catalyst a5, catalyst A8 was aged for 1 hour 30 minutes in a chamber saturated with water and dried in an oven at 120 ℃ for 12 hours under air.

The catalyst A8 obtained after drying had a molybdenum (MoO) content of 18.5% by weight₃Equivalent), 4.5% by weight of cobalt (CoO equivalent) and 1.3% by weight of phosphorus (P)₂O₅Equivalent), the atomic ratio Co/Mo is 0.43, the atomic ratio P/Mo is 0.33, and the specific surface area is 103 m/g. The molar ratio of the added group VIb metal to the group VIb metal already present in the spent catalyst A5 was 0.8 mol/mol.

Example 9 evaluation of catalyst A1 (fresh), A2, A3 and A4

A representative model Feed of Catalytic Cracking (FCC) gasoline, containing 10 wt% 2, 3-dimethylbut-2-ene and 0.33 wt% 3-methylthiophene (i.e., 1000ppm by weight sulfur in the feed), was used to evaluate the catalytic performance of various catalysts. The solvent used was heptane.

The Hydrodesulfurization (HDS) reaction was carried out in a fixed transverse bed reactor at a total pressure of 1.5MPa, 210 ℃ and HSV =6h^-1(HSV = feed volumetric flow rate/catalyst volume) was carried out in the presence of 4 ml of catalyst. Before HDS reaction, under atmospheric pressure, in the presence of 15 mol% H₂H of S₂The catalyst was sulfided in situ at 350 ℃ for 2 hours.

Each catalyst was placed in the reactor in turn. Samples were taken at different time intervals and analyzed by gas chromatography to observe the disappearance of the reactants and the formation of the product.

The quality of the catalytic performance of the catalyst was evaluated from the catalytic activity and selectivity. HDS activity is represented by the HDS reaction rate constant (kHDS) of 3-methylthiophene, normalized to the volume of catalyst introduced (assuming first order kinetics with respect to the kinetics of the sulfur compounds). The HydO activity is expressed by the rate constant of the olefin hydrogenation (HydO), i.e.in this case, for the hydrogenation of 2, 3-dimethylbut-2-ene, normalized with respect to the volume of catalyst introduced (assuming first order kinetics with respect to the olefin). The selectivity of the catalyst is expressed as the normalized ratio of rate constants kHDS/kHydO. The higher the selectivity of the catalyst, the higher the kHDS/kHydO ratio, which indicates that the hydrogenation of 2, 3-dimethylbut-2-ene is limited. Therefore, an increase in the kHDS/kHydO ratio is advantageous for the quality of the gasoline obtained at the end of the hydrodesulphurization reaction, since the loss of octane number of the gasoline obtained is significantly minimized, since the hydrogenation of the olefins is limited.

The table below gives the HDS activity and selectivity of the catalyst. The values were normalized by taking fresh catalyst a1 as reference, that is to say the HDS activity and selectivity of catalysts a2, A3 and a4 were compared with the HDS activity and selectivity of fresh catalyst a1, whose HDS activity and selectivity were set at 100. It was observed that the catalyst according to the invention showed an increase in selectivity while maintaining the activity.

TABLE 2

Catalyst and process for preparing same	A1 (comparison)	A2	A3	A4
					Relative HDS Activity	100	102	108	111
Relative selectivity	100	118	126	127

Example 10 evaluation of catalysts A5, A6, A7 and A8

Catalysts a5 (fresh), a6, a7 and A8 were tested under the conditions of example 9. The HDS activity and selectivity of the catalyst are given in the table below. The values were normalized by taking fresh catalyst a5 as a reference, that is, the HDS activity and selectivity of catalysts a6, a7 and A8 were compared with the HDS activity and selectivity of fresh catalyst a5 (which HDS activity and selectivity were set to 100). It was observed that the catalyst according to the invention showed an increase in selectivity while maintaining activity.

TABLE 3

Catalyst and process for preparing same	A5 (comparison)	A6	A7	A8
					Relative activity of HDS	100	100	105	109
Relative selectivity	100	107	111	115