A method for refining and hydrodesulfurization in the presence of a catalyst on a mesoporous-macroporous support.

Abstract

A method for treating partially desulfurized sulfur-containing hydrocarbon feedstock from a preliminary hydrodesulfurization step in the presence of a catalyst comprising an active phase containing a Group VIII metal and a mesoporous-macroporous alumina support having a bimodal mesoporous distribution, wherein: - the volume of mesopores with a diameter greater than or equal to 2 nm and less than 18 nm is 10 to 30% by volume of the total pore volume of the support; - the volume of mesopores with a diameter greater than or equal to 18 nm and less than 50 nm is 30 to 50% by volume of the total pore volume of the support; - the volume of macropores with a diameter greater than or equal to 50 nm and less than 8000 nm is 30 to 50% by volume of the total pore volume of the support.

Description

Technical Field

[0001] This invention relates to the field of hydrotreating gasoline fractions, particularly gasoline fractions produced by fluidized bed catalytic cracking units. More specifically, this invention relates to the use of catalysts in methods for producing low-sulfur gasoline. This invention is particularly suitable for treating gasoline fractions containing olefins and sulfur, such as gasoline produced by catalytic cracking, for which it is desirable to reduce the sulfur compound content without hydrogenating the olefins and aromatics. Existing technology

[0002] Automotive fuel regulations require a significant reduction in the sulfur content of these fuels, especially gasoline. This reduction specifically targets the limits on sulfur and nitrogen oxides in vehicle exhaust. Since 2009, the current European gasoline fuel regulations have set a maximum sulfur content of 10 ppm (parts per million by weight). Similar regulations are in effect in other countries, such as the United States and China, which have required the same maximum sulfur content since January 2017. To meet these regulations, gasoline must be treated with desulfurization methods.

[0003] The primary source of sulfur in gasoline base is "cracked" gasoline, mainly gasoline fractions obtained from the catalytic cracking of crude oil residues obtained through atmospheric or vacuum distillation. Gasoline fractions from catalytic cracking account for an average of 40% of the gasoline base, but actually account for over 90% of the sulfur in gasoline. Therefore, the production of low-sulfur gasoline requires a desulfurization step in catalytic cracking. Other potential sources of sulfur in gasoline include coking gasoline, viscosity-reducing cracked gasoline, or gasoline obtained to a lesser extent from atmospheric distillation or steam cracking.

[0004] Desulfurization of gasoline fractions involves specifically treating these sulfur-rich gasolines in the presence of hydrogen using desulfurization methods. These are subsequently known as hydrodesulfurization (HDS) methods. However, these gasoline fractions, especially those from FCCs, contain a large proportion of monoolefins (approximately 20% to 50% by weight, which contribute to a good octane number), dienes (0.5% to 5% by weight), and unsaturated compounds in the form of aromatics. These unsaturated compounds are unstable and react during hydrodesulfurization. Diolefins polymerize during hydrodesulfurization to form gums. This gum formation leads to gradual deactivation of the hydrodesulfurization catalyst or gradual blockage of the reactor. Therefore, dienes must be removed by hydrotreating before any treatment of these gasolines. Conventional treatment methods, by hydrogenating most of the monoolefins rather than selectively desulfurizing the gasoline, result in high octane number loss and high hydrogen consumption. The latest hydrodesulfurization methods can desulfurize cracked gasoline rich in monoolefins while limiting the hydrogenation of monoolefins and thus limiting octane number loss. Such methods are described, for example, in EP-A-1077247 and EP-A-1174485.

[0005] However, when very deep desulfurization of cracked gasoline is required, some olefins present in the cracked gasoline are hydrogenated on one hand and recombined with H2S on the other to form thiols. These compounds, with the chemical formula R-SH, where R is an alkyl group, are commonly referred to as recombined thiols and typically account for 20% to 80% by weight of residual sulfur in desulfurized gasoline. The reduction in the content of recombined thiols can be achieved through catalytic hydrodesulfurization, but this results in the hydrogenation of most of the monoolefins present in the gasoline, which subsequently leads to a significant decrease in the gasoline's octane number and excessive hydrogen consumption. Furthermore, it is known that the octane number loss due to the hydrogenation of monoolefins during the hydrodesulfurization step increases with the lower the target sulfur content, i.e., when attempting to completely remove sulfur compounds present in the feedstock.

[0006] Therefore, gasoline can be processed in sequence using two reactors as described in document EP1077247; the first stage, also known as the selective HDS stage, typically aims to achieve deep desulfurization of gasoline at the lowest olefin saturation (and without aromatic loss), thereby maximizing octane number retention. The catalyst used is typically a CoMo type catalyst. During this stage, the H2S generated by desulfurization recombines with olefins to form new sulfur compounds: recombinant thiols.

[0007] The second stage typically serves to minimize the amount of recombinant thiols. The temperature in the second stage is usually higher to thermodynamically promote thiols removal. In practice, a furnace is therefore placed between the two reactors so that the temperature of the second reactor can be raised above that of the first reactor.

[0008] The catalysts used in refining processes must be highly selective to avoid olefin saturation (and the loss of aromatics) that would lead to octane number loss. Therefore, it is essential to reduce the total sulfur and mercaptan content in the hydrocarbon fraction, preferably the gasoline fraction, to very low levels while minimizing the reduction in octane number. Typically, the catalysts used are nickel-based.

[0009] Furthermore, it is known from the prior art that the pore distribution of the catalyst support can have a beneficial effect on catalytic performance.

[0010] US 6,589,908 discloses a method for preparing a catalyst support that is free of macropores and has a bimodal pore structure within mesopores, separating the two pore modes by 1 to 20 nm. This support can be used in a variety of catalytic applications, particularly for hydrotreating, especially for hydrodenitrification.

[0011] US 5,266,300 discloses a method for preparing a porous alumina support, which is used as a catalyst support for hydrodesulfurization or hydrodemetallization, wherein the support comprises 0.65 to 1.30 cm³ of... 3 The porous carrier comprises two macropore groups, wherein approximately 2% to 20% of the total pore volume is a macropore form with a diameter of 10,000 to 100,000 angstroms (1,000 to 10,000 nm), approximately 5% to 30% of the total pore volume is a macropore form with a diameter of 1,000 to 10,000 angstroms (100 to 1,000 nm), and approximately 50% to 93% of the total pore volume is a mesopore form with a pore size of 30 to 1,000 angstroms (3-100 nm).

[0012] Documents CN108855197, CN104248987 and CN104248985 disclose catalysts for various catalytic applications (propane dehydrogenation, esterification), whose supports have a three-peak pore distribution, with the mesopore group concentrated on three peaks, which are 2 to 4 nm, 5 to 15 nm and 10 to 40 nm, respectively.

[0013] Document US 7,790,130 discloses alumina for halide removal comprising trimodal porosity, wherein 40 vol% to 49 vol% of the total pore volume relative to the carrier is in the form of pores with a diameter of 15 to 50 nm.

[0014] However, no existing technical literature describes the use of methods for treating partially desulfurized sulfur-containing hydrocarbon feedstocks generated from the preliminary steps of catalytic hydrodesulfurization in the presence of a catalyst comprising a support having bimodal mesoporous pore size, high-medium pore volume, and a specific macropore volume.

[0015] In this context, one of the objectives of the present invention is to provide a hydrodesulfurization method in the presence of a supported catalyst, particularly the refining stage of a two-step hydrodesulfurization method, wherein the supported catalyst performs at least as well as, and in fact even better than, methods known in the prior art in reducing the total sulfur and mercaptan content in the hydrocarbon fraction, while minimizing the reduction in octane number.

[0016] The applicant has discovered that the use of a catalyst comprising an active phase based on at least one Group VIII metal (the active phase containing no Group VIB elements) on a mesoporous and macroporous support, having bimodal mesoporous pore size and high-medium pore volume as well as a given macroporous volume, results in improved catalytic performance in terms of both catalytic activity and selectivity when used in a method for treating a partially desulfurized sulfur-containing hydrocarbon feedstock obtained from a preliminary hydrodesulfurization step. This leads to better feedstock conversion under the same operating conditions as those used in the prior art.

[0017] Specifically, unbound by any scientific theory, such a catalyst is used in methods for treating partially desulfurized sulfur-containing hydrocarbon feedstocks produced by the initial step of catalytic hydrodesulfurization. The presence of mesopores of varying sizes improves the internal diffusion of reactants and products. Furthermore, when the feedstock contains significant amounts of reactive olefins (unsaturated compounds), particularly dienes, the simultaneous presence of macropores is particularly recommended. This is the case with gasoline, where dienes can cause gum formation and thus clog the catalyst pores in the absence of macropores.

[0018] Invention Theme

[0019] This invention relates to a method for processing partially desulfurized sulfur-containing hydrocarbon feedstock produced by a preliminary step of catalytic hydrodesulfurization, wherein the method is carried out at a temperature of 200°C to 400°C, a pressure of 0.2 to 5 MPa, and a time of 0.1 h. -1 Up to 20h -1 The process is carried out at a space-time velocity in the presence of an active phase comprising at least one Group VIII metal and a catalyst on a mesoporous-macroporous alumina support having a bimodal mesoporous distribution, wherein the space-time velocity is defined as the volumetric flow rate of the feed at the inlet divided by the volume of the catalyst used, the active phase being free of any Group VIB metal, and wherein:

[0020] - The volume of mesopores with a diameter greater than or equal to 2 nm and less than 18 nm corresponds to 10% to 30% of the total pore volume of the carrier;

[0021] - The volume of mesopores with a diameter greater than or equal to 18 nm and less than 50 nm corresponds to 30% to 50% of the total pore volume of the carrier;

[0022] - The volume of macropores with a diameter greater than or equal to 50 nm and less than 8000 nm corresponds to 30% to 50% of the total pore volume of the carrier.

[0023] According to one or more embodiments, the specific surface area of ​​the carrier is 50 to 210 m². 2 / g.

[0024] According to one or more embodiments, the total pore volume of the carrier is 0.7 to 1.3 ml / g.

[0025] According to one or more embodiments, the volume of mesopores with a diameter greater than or equal to 2 nm and less than 18 nm corresponds to 15% to 25% of the total pore volume of the carrier.

[0026] According to one or more embodiments, the volume of mesopores with a diameter greater than or equal to 18 nm and less than 50 nm corresponds to 35% to 45% of the total pore volume of the carrier.

[0027] According to one or more embodiments, the volume of macropores with a diameter greater than or equal to 50 nm and less than 8000 nm corresponds to 35% to 50% of the total pore volume of the carrier.

[0028] According to one or more embodiments, the content of Group VIII metals in the catalyst, expressed as Group VIII elements, is from 5% to 65% by weight relative to the total weight of the catalyst.

[0029] According to one or more embodiments, the Group VIII metal is nickel.

[0030] According to one or more embodiments, the pore distribution of mesopores with a diameter greater than or equal to 2 nm and less than 18 nm is concentrated in the numerical range of 10.5 to 14.5 nm.

[0031] According to one or more embodiments, the pore distribution of mesopores with a diameter greater than or equal to 18 nm and less than 50 nm is concentrated in the numerical range of 22 to 28 nm.

[0032] According to one or more embodiments, the specific surface area of ​​the carrier is 70 to 180 m². 2 / g.

[0033] According to one or more embodiments, the carrier is in the form of beads with a diameter of 2 to 4 mm.

[0034] According to one or more embodiments, when the carrier is in the form of beads, the carrier is obtained according to the following steps:

[0035] s1) Dehydrate aluminum hydroxide or aluminum hydroxide at a temperature of 400°C to 1200°C, preferably 600°C to 900°C, for 0.1 seconds to 5 seconds, preferably 0.1 seconds to 4 seconds, to obtain aluminum oxide powder;

[0036] s2) The alumina powder obtained in step s1) is shaped into beads;

[0037] s3) Alumina beads obtained in step s2) are heat-treated at a temperature of 200°C or higher;

[0038] s4) Alumina beads obtained at the end of step s3) are obtained by immersion in water or an aqueous solution and then residence in an autoclave at a temperature of 100°C to 300°C.

[0039] s5) Calcine the alumina beads obtained at the end of step s4) at a temperature of 500°C to 820°C.

[0040] According to one or more embodiments, the partially desulfurized hydrocarbon feedstock contains less than 100 ppm by weight of sulfur. Invention Details

[0042] 1. Definition

[0043] In the following text, the groups of chemical elements are given according to the CAS classification (CRC Handbook of Chemistry and Physics, published by CRC Press, edited by DRLide, 81st edition, 2000-2001). For example, Group VIII according to the CAS classification corresponds to the metals in columns 8, 9, and 10 according to the new IUPAC classification.

[0044] BET specific surface area is measured by physical adsorption of nitrogen gas according to standard ASTM D3663-03, as described in the book "Adsorption by Powders & Porous Solids: Principles, Methodology and Applications" by Rouquerol F., Rouquerol J. and Singh K., Academic Press, 1999.

[0045] In this specification, according to IUPAC convention, "micropore" should be understood as a pore with a diameter less than 2 nm, i.e., 0.002 μm; "medium pore" should be understood as a pore with a diameter greater than 2 nm, i.e., 0.002 μm, and less than 50 nm, i.e., 0.05 μm; and "large pore" should be understood as a pore with a diameter greater than or equal to 50 nm, i.e., 0.05 μm.

[0046] In the following description of the invention, the “total pore volume” of alumina or catalyst should be understood as the volume measured by mercury porosimetry at a maximum pressure of 4000 bar (400 MPa), using a surface tension of 484 dynes / cm and a contact angle of 140°. Following the recommendation in the publication “Techniques de l′ingénieur, traité analyze etcaractérisation” [Techniques of the Engineer, Analysis and Characterization Treatment], pp. 1050-5, by Jean Charpin and Bernard Rasneur, the wetting angle is taken as 140°.

[0047] To obtain better accuracy, the total pore volume values ​​(in ml / g) given below correspond to the total mercury volume measured on the sample (total pore volume measured by mercury porosimetry) (in ml / g) minus the mercury volume measured on the same sample at a pressure corresponding to 30 psi (approximately 0.2 MPa) (in ml / g).

[0048] The volumes of macro- and meso-orifices were measured by mercury intrusion porosimetry under a maximum pressure of 4000 bar (400 MPa), using a surface tension of 484 dynes / cm and a contact angle of 140°, according to standard ASTM D4284-83.

[0049] When the value is equal to or higher than a certain value, mercury fills all interparticle voids. This value is set at 0.2 MPa, and it is believed that when the value is higher than this, mercury penetrates into the pores of the sample.

[0050] The macropore volume of a catalyst is defined as the cumulative volume of mercury introduced under pressures ranging from 0.2 MPa to 30 MPa, corresponding to the volume contained in pores with an apparent diameter greater than 50 nm.

[0051] The mesopore volume of a catalyst is defined as the cumulative volume of mercury introduced under pressures of 30 MPa to 400 MPa, corresponding to the volume contained in pores with apparent diameters of 2 to 50 nm.

[0052] When the incremental pore volume measured by mercury porosimetry is plotted as a function of pore diameter, the pore size modes correspond to the inflection points of the function.

[0053] The contents of Group VIII elements and phosphorus were measured by X-ray fluorescence method.

[0054] 2. Description

[0055] Refining Hydrodesulfurization Method

[0056] According to the present invention, a method for treating a partially desulfurized sulfur-containing hydrocarbon feedstock produced by a preliminary step of catalytic hydrodesulfurization is provided, wherein the feedstock to be treated is contacted with a refining catalyst. The hydrodesulfurization step (referred to as the refining hydrodesulfurization step) is primarily intended to decompose recombinant thiols at least partially into olefins and H₂S, but it also allows for the hydrodesulfurization of more difficult-to-treat sulfur compounds, while the first hydrodesulfurization step is primarily intended to convert most of the sulfur compounds into H₂S. The remaining sulfur compounds are essentially difficult-to-treat sulfur compounds and recombinant thiols produced by the addition of the formed H₂S.

[0057] The refining hydrodesulfurization process is typically carried out at a temperature of 280°C to 400°C, preferably 300°C to 380°C, and most preferably 310°C to 370°C. The temperature of this refining step is typically at least 5°C higher than that of the first hydrodesulfurization step, preferably at least 10°C, and most preferably at least 30°C.

[0058] This method typically takes 1 hour -1 Up to 10h -1 1 hour preferred -1 up to 8h -1 The process is carried out at the space velocity (defined as the volumetric flow rate of the feedstock at the inlet divided by the volume of the catalyst used).

[0059] This method is typically carried out at a hydrogen flow rate such that, at a standard m 3 / hour (Nm 3 Hydrogen flow rate expressed as / h) and under standard conditions in m 3 The ratio between the flow rates of the raw materials to be processed, expressed as / hour, is 10 Nm. 3 / m 3 Up to 4000 Nm 3 / m 3 50Nm preferred 3 / m 3 Up to 1000 Nm 3 / m 3 .

[0060] This method is typically carried out at pressures of 0.5 MPa to 5 MPa, preferably 1 MPa to 3 MPa.

[0061] The partially desulfurized sulfur-containing hydrocarbon feedstock is preferably gasoline containing olefin compounds, and more preferably a gasoline fraction obtained from catalytic cracking. The treated hydrocarbon feedstock typically has a boiling point below 350°C, preferably below 300°C, and very preferably below 250°C. Preferably, the hydrocarbon feedstock contains less than 100 ppm by weight of sulfur, particularly sulfur derived from organic compounds, preferably less than 50 ppm by weight of sulfur, especially sulfur derived from organic compounds, particularly in the form of reconstituted thiols and difficult-to-treat sulfur compounds.

[0062] Prior to the refining step, the feedstock is partially desulfurized. This preliminary treatment involves contacting the sulfur-containing hydrocarbon feedstock with hydrogen in one or more hydrodesulfurization reactors connected in series, each reactor containing one or more catalysts suitable for hydrodesulfurization. Preferably, the operating pressure of this step is typically 0.5 MPa to 5 MPa, very preferably 1 MPa to 3 MPa, and the temperature is typically 200°C to 400°C, very preferably 220°C to 380°C. Preferably, the amount of catalyst used in each reactor is such that the flow rate of the gasoline to be treated (in m³ / s under standard conditions) is... 3 (per hour) and per m 3 The ratio between catalysts is 0.5h. -1 Up to 20h -1 1 hour is the best option -1 Up to 10h -1 Preferably, the hydrogen flow rate is typically such that, in standard m 3 / hour (Nm 3 Hydrogen flow rate expressed as / h) and under standard conditions in m 3 The ratio between the flow rates of the raw materials to be processed, expressed as / hour, is 50 Nm. 3 / m 3 Up to 1000 Nm 3 / m 3 70Nm preferred 3 / m 3 Up to 800 Nm 3 / m 3 Preferably, this step is carried out for selective hydrodesulfurization, i.e., the degree of hydrogenation of the monoolefin is less than 80% by weight, preferably less than 70% by weight, and very preferably less than 60% by weight.

[0063] The degree of desulfurization achieved in this hydrodesulfurization step is typically greater than 50%, preferably greater than 70%, such that the hydrocarbon fraction used in the refining process contains less than 100 ppm by weight of sulfur, preferably less than 50 ppm by weight of sulfur.

[0064] Any hydrodesulfurization catalyst can be used in the initial hydrodesulfurization step. Preferably, a catalyst with high selectivity for hydrodesulfurization compared to olefin hydrogenation is used. Such a catalyst comprises at least one porous amorphous inorganic support, a Group VIB metal, or a Group VIII metal. The Group VIB metal is preferably molybdenum or tungsten, and the Group VIII metal is preferably nickel or cobalt. The support is typically selected from alumina, silica, silica-alumina, silicon carbide, titanium dioxide (alone or as a mixture with alumina or silica-alumina), and magnesium oxide (alone or as a mixture with alumina or silica-alumina). Preferably, the support is selected from alumina, silica, and silica-alumina. Preferably, the hydrodesulfurization catalyst used in one or more additional hydrodesulfurization steps has the following characteristics:

[0065] - The content of Group VIB elements is 1% to 20% by weight of oxides of Group VIB elements relative to the total weight of the catalyst;

[0066] - The content of Group VIII elements is 0.1% to 20% by weight of oxides of Group VIII elements relative to the total weight of the catalyst;

[0067] The molar ratio of group VIII elements to group VIB elements is 0.1 to 0.8.

[0068] A highly preferred hydrodesulfurization catalyst comprises cobalt and molybdenum and has the characteristics described above. Furthermore, the hydrodesulfurization catalyst may contain phosphorus. In this case, the phosphorus content is preferably 0.1% to 10% by weight of P2O5 relative to the total weight of the catalyst, and the molar ratio of phosphorus to Group VIB elements is greater than or equal to 0.25, preferably greater than or equal to 0.27.

[0069] At the end of the hydrodesulfurization step, the effluent can be separated into hydrogen and H2S by any method known to those skilled in the art (disengager, stabilizer, etc.).

[0070] catalyst

[0071] The active phase of the catalyst used in the method according to the invention comprises an active phase based on at least one Group VIII metal, preferably consisting of an active phase based on at least one Group VIII metal, wherein the active phase does not contain any Group VIB metal.

[0072] Preferably, the Group VIII metal is nickel.

[0073] Preferably, the active phase of at least one Group VIII metal is in sulfide form. In this application, the active phase of at least one Group VIII metal in sulfide form refers to M... x Sy Nickel sulfide compounds are of the type where M is a Group VIII metal, 0.5 ≤ x / y ≤ 2, preferably x = 1 and y = 1, or x = 3 and y = 2. When the Group VIII metal is nickel, the most common compounds are hexagonal or rhombohedral NiS, or Ni3S2. When the Group VIII metal is nickel, the nickel sulfide phase diagram exhibits a large number of sulfur-rich and nickel-rich phases at low temperatures. Therefore, various nickel sulfide phases and stoichiometry are possible, ranging from nickel-rich compounds such as Ni3S2, Ni6S5, Ni7S6, Ni9S8, and NiS to sulfur-rich compounds such as Ni3S4 and NiS2. It should be noted that NiS is also known to exist in two main phases: hexagonal α-NiS, which is stable at high temperatures, and rhombohedral β-NiS, which is stable at low temperatures. The presence of these numerous phases makes the synthesis of nickel sulfides as single-phase complexes possible, and therefore the products are often mixtures of two or more phases.

[0074] The content of Group VIII elements, expressed as Group VIII elements, is preferably 5% to 65% by weight, more preferably 8% to 55% by weight, even more preferably 12% to 40% by weight, and particularly preferably 12% to 34% by weight, relative to the total weight of the catalyst.

[0075] The specific surface area of ​​the catalyst is typically 50 to 200 m². 2 / g, preferably 60 to 170m 2 / g, preferably 70 to 130m 2 / g.

[0076] The pore volume of the catalyst is typically from 0.5 ml / g to 1.3 ml / g, preferably from 0.6 ml / g to 1.1 ml / g.

[0077] Alumina carrier

[0078] In the case of the hydrodesulfurization method according to the present invention, the alumina support for the catalyst is a macroporous-mesoporous alumina support with a bimodal mesoporous distribution, wherein:

[0079] - The volume of mesopores with a diameter greater than or equal to 2 nm and less than 18 nm corresponds to 10% to 30% of the total pore volume of the carrier;

[0080] - The volume of mesopores with a diameter greater than or equal to 18 nm and less than 50 nm corresponds to 30% to 50% of the total pore volume of the carrier;

[0081] - The volume of macropores with a diameter greater than or equal to 50 nm and less than 8000 nm corresponds to 30% to 50% of the total pore volume of the carrier.

[0082] Preferably, the volume of the mesopores in the carrier with a diameter greater than or equal to 2 nm and less than 18 nm corresponds to 15% to 25% of the total pore volume of the carrier.

[0083] Preferably, the volume of the mesopores in the carrier with a diameter greater than or equal to 18 nm and less than 50 nm corresponds to 35% to 45% of the total pore volume of the carrier.

[0084] Preferably, the volume of macropores in the carrier with a diameter greater than or equal to 50 nm and less than 8000 nm corresponds to 35% to 50% of the total pore volume of the carrier.

[0085] In one embodiment of the invention, the pore distribution of mesopores with a diameter greater than or equal to 2 nm and less than 18 nm is concentrated in the range of 10.5 to 14.5 nm, preferably 12 to 13 nm.

[0086] In one embodiment of the invention, the pore distribution of mesopores with a diameter greater than or equal to 18 nm and less than 50 nm is concentrated in the range of 22 to 28 nm, preferably 23 to 27 nm.

[0087] The specific surface area of ​​the carrier is typically 50 to 210 m². 2 / g, preferably 70 to 180m 2 / g, or even more preferably 70 to 160 mg 2 / g.

[0088] The pore volume of the carrier is typically from 0.7 ml / g to 1.3 ml / g, preferably from 0.8 ml / g to 1.2 ml / g.

[0089] Advantageously, the carrier is in the form of beads having a diameter of 0.8 to 10 mm, preferably 1 to 5 mm, more preferably 2 to 4 mm.

[0090] Methods for preparing carriers

[0091] The alumina support for the catalyst used in the treatment method according to the invention can be synthesized by any method known to those skilled in the art.

[0092] According to a preferred embodiment, the alumina support used in this invention is in bead form. According to this preferred embodiment, the preparation of the support includes the following steps:

[0093] s1) At a temperature of 400°C to 1200°C, preferably 600°C to 900°C, aluminum hydroxide or aluminum hydroxide is dehydrated for 0.1 seconds to 5 seconds, preferably 0.1 seconds to 4 seconds, to obtain aluminum oxide powder;

[0094] s2) The alumina powder obtained in step s1) is shaped into beads;

[0095] s3) Alumina beads obtained in step s2) are heat-treated at a temperature of 200°C or higher;

[0096] s4) Alumina beads are obtained by impregnation with water or an aqueous solution, preferably an acidic aqueous solution, and then by retention in an autoclave at a temperature of 100°C to 300°C, preferably 150°C to 250°C, at the end of the hydrothermal treatment step s3).

[0097] s5) Calcine the alumina beads obtained at the end of step s4) at a temperature of 500°C to 820°C.

[0098] Steps s1) to s5) are described in detail below.

[0099] Step s1)

[0100] According to step s1), aluminum hydroxide or aluminum hydroxide is dehydrated at a temperature of 400°C to 1200°C, preferably 600°C to 900°C, for 0.1 seconds to 5 seconds, preferably 0.1 seconds to 4 seconds, to obtain alumina powder. Aluminum hydroxide may be selected from hydrargillite, gibbsite, or bayerite. Aluminum hydroxide may be selected from boehmite or diaspore.

[0101] Preferably, step s1) is performed using hydrated bauxite.

[0102] Typically, step s1) is carried out in the presence of a hot airflow (e.g., dry or humid air) to allow for the rapid removal and entrainment of evaporated water.

[0103] Typically, activated alumina powder obtained by dehydrating aluminum hydroxide or aluminum hydroxide is ground to a particle size of 10 to 200 μm.

[0104] Typically, the activated alumina powder obtained after dehydrating aluminum hydroxide or aluminum hydroxide is washed with water or an acidic aqueous solution. When using an acidic aqueous solution for the washing step, any inorganic or organic acid can be used, preferably nitric acid, hydrochloric acid, perchloric acid, or sulfuric acid for inorganic acids, and carboxylic acids (formic acid, acetic acid, or malonic acid), sulfonic acids (p-toluenesulfonic acid), or sulfate esters (lauryl sulfate) for organic acids.

[0105] Step s2)

[0106] According to step s2), the alumina powder obtained at the end of step s1) is shaped.

[0107] The alumina powder is shaped into beads, a process known as granulation, typically using rotary techniques such as rotary granulators or drums. These methods allow for the production of beads with controlled diameter and pore distribution, dimensions and distributions that are usually generated during the agglomeration step.

[0108] Pores can be created in various ways, such as by selecting the particle size distribution of the alumina powder or by agglomerating several alumina powders with different particle size distributions. Another method involves mixing one or more compounds, called pore-forming compounds, with the alumina powder before or during the agglomeration step. These pore-forming compounds are dissolved by heating, thereby creating pores in the beads. Pore-forming compounds used can be mentioned as, for example, wood flour, charcoal, activated carbon, carbon black, sulfur, tar, plastics, or emulsions of plastics such as polyvinyl chloride, polyvinyl alcohol, naphthalene, etc. The amount of pore-forming compound added is determined by the desired volume to obtain a porosity of 500 to 1100 kg / m³. 3 Preferred weight is 700 to 950 kg / m³ 3 The original green filling density and the beads have a diameter of 0.8 to 10 mm, preferably 1 to 5 mm, and even more preferably 2 to 4 mm. The obtained beads can be selected by sieving according to the desired particle size.

[0109] Step s3)

[0110] According to step s3), the shaped alumina powder in bead form obtained at the end of step s2) is heat-treated at a temperature above or equal to 200°C, preferably 200°C to 1200°C, preferably 300°C to 900°C, and most preferably 400°C to 750°C, for a period typically of 1 to 24 hours, preferably 1 to 6 hours. The specific surface area of ​​the beads obtained in this intermediate step is 50 to 420 m². 2 / g, preferably 60 to 350m 2 / g, or even more preferably 80 to 300 mg 2 / g.

[0111] Step s4)

[0112] According to step s4), the alumina beads obtained at the end of step s3) are subjected to hydrothermal treatment by impregnation with water or an aqueous solution, preferably an acidic aqueous solution, and then placed in an autoclave at a temperature of 100°C to 300°C, preferably 150°C to 250°C.

[0113] Hydrothermal treatment is typically carried out at temperatures between 100°C and 300°C, preferably between 150°C and 250°C, for more than 45 minutes, preferably 1 to 24 hours, and most preferably 1.5 to 12 hours. The hydrothermal treatment is usually carried out using an acidic aqueous solution containing one or more inorganic and / or organic acids, preferably nitric acid, hydrochloric acid, perchloric acid, sulfuric acid, or a weak acid, with a pH below 4, such as acetic acid or formic acid. Typically, the acidic aqueous solution also contains one or more compounds capable of releasing anions that can bind to aluminum ions, preferably including nitrate ions (e.g., aluminum nitrate), chloride ions, sulfate ions, perchlorate ions, chloroacetic acid ions, trichloroacetic acid ions, bromoacetic acid ions, or dibromoacetic acid ions, and compounds with anions of the general formula R-COO (such as formate and acetate ions).

[0114] Step s5)

[0115] According to step s5), the alumina beads obtained at the end of step s4) are calcined at a temperature of 500°C to 820°C, preferably 550°C to 750°C, typically for 1 hour to 24 hours, preferably 1 hour to 6 hours. At the end of this step, the specific surface area of ​​the resulting alumina beads is 50 to 210 m². 2 / g, preferably 70 to 180m 2 / g, or even more preferably 70 to 160 mg 2 / g.

[0116] Methods for preparing catalysts

[0117] The catalyst used in the hydrodesulfurization method according to the present invention is obtained by a preparation method comprising at least the following steps:

[0118] a) Contact the alumina support with at least one metal salt in a solution containing at least one Group VIII metal;

[0119] b) Drying the solid obtained at the end of step a) at a temperature below 200°C to obtain a dried catalyst precursor;

[0120] c) Optionally, the dried catalyst precursor obtained at the end of step b) is calcined in an inert or oxygen-containing atmosphere at a temperature of 200°C or higher and 1100°C or lower to obtain a calcined catalyst precursor.

[0121] d) Optionally, the catalyst precursor obtained at the end of step b) or optionally at the end of step c) is reduced to obtain a reduced catalyst precursor.

[0122] e) Optionally, the catalyst precursor obtained at the end of step b) or optionally at the end of step c) or d) is sulfided.

[0123] The steps of the method for preparing the catalyst are described in detail below.

[0124] Step a)

[0125] According to step a), the porous support is contacted with a metal salt in a solution containing at least one Group VIII metal. According to step a), the porous support and the metal salt in the solution can be contacted by any method known to those skilled in the art. Preferably, step a) is carried out by dry impregnation, which involves contacting the porous support with a solution having a volume of 0.25 to 1.5 times the pore volume of the support. The solution containing at least one metal salt comprising at least one Group VIII metal can be aqueous or organic, preferably aqueous.

[0126] According to step a), at least one metal salt is provided, which comprises at least one metal belonging to Group VIII. Preferably, the metal is nickel. Preferably, the metal salt is hydrated. Preferably, the metal salt is a hydrated nitrate. Preferably, the metal salt is nickel nitrate hexahydrate (Ni(NO3)2·6H2O).

[0127] Step b)

[0128] According to step b), the solid obtained at the end of step a) is dried at a temperature below 200°C to obtain a dried catalyst precursor. Preferably, the drying is carried out at a temperature of 50°C to 180°C, more preferably 70°C to 150°C, and very preferably 75°C to 130°C. The drying step is preferably carried out for a period of time typically from 10 minutes to 24 hours. Longer periods are not excluded, but do not necessarily provide any improvement.

[0129] The drying step can be carried out by any technique known to those skilled in the art. It is advantageously carried out at atmospheric pressure or under reduced pressure. Preferably, the step is carried out at atmospheric pressure. It is advantageously carried out using hot air or any other hot gas. Preferably, the gas used is air, or an inert gas such as argon or nitrogen. Very preferably, drying is carried out in the presence of nitrogen and / or air.

[0130] Step c)(Optional)

[0131] According to step c), the solid obtained in step b) is calcined under an inert atmosphere (e.g., nitrogen) or an oxygen-containing atmosphere (e.g., air) at a temperature above or equal to 200°C and below or equal to 1100°C, preferably 250°C to 650°C, and most preferably 300°C to 500°C. The duration of this heat treatment is typically less than 16 hours, preferably less than 5 hours. After this treatment, the Group VIII elements are in oxide form, and the solid no longer contains or contains very little of the counterions and water of crystallization initially present in the metal salt. The calcination step can be carried out by any technique known to those skilled in the art. It is advantageously carried out in a traversed bed or fluidized bed using hot air or any other hot gas. The calcined catalyst precursor is obtained.

[0132] Step d)(Optional)

[0133] Prior to catalyst sulfidation, after step b), and optionally after step c), at least one reduction treatment step is performed in the presence of a reducing gas to obtain a catalyst comprising at least one Group VIII metal in at least partially metallic form. This treatment allows for the formation of metal particles, particularly Group VIII metal particles in the zero-valence state. The reducing gas is preferably hydrogen. Hydrogen can be used as pure hydrogen or as a mixture (e.g., hydrogen / nitrogen, hydrogen / argon, or hydrogen / methane mixture). When hydrogen is used as a mixture, any proportion is conceivable.

[0134] The reduction treatment is preferably carried out at a temperature of 120 to 500°C, more preferably 150 to 450°C. The duration of the reduction treatment is typically 2 to 40 hours, preferably 3 to 30 hours. The temperature is typically raised to the desired reduction temperature slowly, for example, at a rate of 0.1 to 10°C / min, preferably 0.3 to 7°C / min. A reduced catalyst precursor is obtained.

[0135] Step e)

[0136] Following step b) or, optionally, step c) or d), the obtained product (catalyst precursor, dried, calcined, or reduced catalyst precursor) is advantageously sulfided to form a Group VIII metal sulfide. This sulfidation is carried out by methods known to those skilled in the art, and advantageously in a sulfur-containing reducing atmosphere in the presence of hydrogen and hydrogen sulfide. Sulfidation is carried out by injecting a stream containing H₂S and hydrogen, or a sulfur compound capable of decomposing into H₂S in the presence of a catalyst and hydrogen, onto the catalyst. Polysulfides, such as dimethyl disulfide, are commonly used H₂S precursors for sulfiding catalysts. The temperature is adjusted to allow H₂S to react with the Group VIII metal to form the Group VIII metal sulfide. This sulfidation can be carried out in situ or ex-situ (inside or outside the reactor of the refining process). Advantageously, it is carried out ex-situ. Typically, it is carried out at temperatures from 200°C to 600°C, more preferably from 250°C to 500°C. For reactivity, the Group VIII metal should preferably be substantially sulfided. The sulfidation operating conditions, particularly the properties of the sulfiding agent, the H2S / hydrogen ratio, the sulfidation temperature, and the duration, are preferably adjusted based on the product obtained after step b) or optionally after steps c) or d) to obtain good sulfidation of Group VIII metals, i.e., most and preferably completely sulfidation of Group VIII metals.

[0137] The degree of sulfidation of the metal constituting the active phase of the catalyst is advantageously at least 60%, preferably at least 80%. The sulfur content in the sulfiding material is measured by elemental analysis according to ASTM D5373. A metal is considered sulfided when the total degree of sulfidation, defined by the molar ratio of sulfur (S) present on the catalyst to the metal, is at least 60% of the theoretical molar ratio corresponding to complete sulfidation of the considered metal(s). The total degree of sulfidation is defined by the following equation:

[0138] (S / Element) 催化剂 >= 0.6 × (S / element) 理论

[0139] in:

[0140] (S / Metal) 催化剂 It is the molar ratio of sulfur (S) to metal present on the catalyst;

[0141] (S / Metal) 理论 It corresponds to the molar ratio of sulfur to metal in the form of sulfides produced by the complete sulfidation of metal.

[0142] The theoretical molar ratio varies depending on the metal being considered:

[0143] (S / Ni) 理论 =1 / 1

[0144] The present invention is illustrated by the following embodiments. Example

[0145] Example 1: Catalyst A (according to the present invention)

[0146] The support S1 for catalyst A is made of hydrated bauxite ( Merck TM The alumina powder was obtained by dehydration. The temperature was set to 800°C, and the contact time between the dehydrated material and the dry air stream was 1 second. The obtained alumina powder was ground to a particle size of 10 to 200 μm, and then washed three times with distilled water with a volume equal to twice the volume of the powder used. The alumina powder was then processed with carbon black (N990). In the presence of carbon black, the alumina powder is shaped using a plate granulator (GRELBEX P30) equipped with a conical cylindrical pan at a 30° angle and a rotation speed of 40 rpm, thereby obtaining beads with a diameter mainly of 2 to 4 mm after sieving the solids. The amount of carbon black is adjusted to obtain 800 kg / m³. 3 The original filling density of the target material was determined. The beads were heat-treated in air at 720°C to give them a density of 200 μm. 2 The specific surface area was measured in g. Next, the surface area was determined by using a nitric acid aqueous solution (0.1N, Merck). TM The volume of the impregnated pores was determined, and the beads were subjected to hydrothermal treatment. The hydrothermal treatment was carried out in a rotating basket autoclave at 200°C for 6.5 hours. The resulting beads were then subjected to a final calcination treatment in air at 650°C for 2 hours. The carrier S1 has a diameter of 141m. 2 The specific surface area per g, the total pore volume of 0.97 ml / g, and the following pore distribution obtained by mercury porosimetry:

[0147] - The volume of mesopores with a diameter greater than or equal to 2nm and less than 18nm is 0.15ml / g, which corresponds to 15% of the total pore volume, and their pore distribution is concentrated at 13nm;

[0148] - The volume of mesopores with a diameter greater than or equal to 18 nm and less than 50 nm is 0.43 ml / g, which corresponds to 44% of the total pore volume, and their pore distribution is concentrated at 26 nm;

[0149] - The volume of macropores with a diameter greater than or equal to 50 nm and less than 8000 nm is 0.39 ml / g, corresponding to 40% of the total pore volume.

[0150] Carrier S1 exhibited a water absorption volume of 0.95 ml / g. This was achieved by using 8.24 g of nickel nitrate (Ni(NO3)2·6H2O, 99.5%), Merck... TMThe impregnation solution was prepared by diluting the solid in 37.2 ml of distilled water. After dry impregnation of 40 g of support and aging in a moisture-saturated atmosphere for 12 hours, the solid was dried at 120 °C for 12 hours to obtain the catalyst precursor. The precursor was obtained by using 22.64 g of nickel nitrate (Ni(NO3)2·6H2O, 99.5%), Merck... TM The solution prepared by diluting in 33.7 ml of distilled water was used for the second impregnation step. After the steps of dry impregnation of the catalyst precursor and aging in a moisture-saturated atmosphere for 12 hours, the solid was dried at 120 °C for 12 hours. Subsequently, the solid was calcined in air at 450 °C for 2 hours. The calcined catalyst obtained thus is denoted as A. Subsequently, the final metallic composition of the catalyst (expressed in oxide form and relative to the weight of the dried catalyst) is as follows: NiO = 17.0 ± 0.2 wt% (i.e., the Ni element content is 13.4 wt%) relative to the total weight of the catalyst. Catalyst A has a total pore volume of 0.88 ml / g and a pore size of 118 m 2 Specific surface area per g.

[0151] Example 2: Catalyst B (a catalyst with macropores and mesopores with a unimodal distribution) not according to the present invention

[0152] The support S2 for catalyst B is made by passing hydrated alumina ( The activated alumina powder was prepared by dehydration using Merck (a type of granulator). The temperature was set at 800°C, and the contact time between the dehydrated material and the dry air stream was 1 second. The obtained activated alumina powder was ground to a particle size of 10 to 200 μm and then washed three times with distilled water at a volume equal to twice the volume of the powder used. The powder was then granulated using a disc granulator (GRELBEX) equipped with a conical cylindrical disc. TM P30) shaped the activated alumina powder at a 30° angle and a rotation speed of 40 rpm to obtain a diameter mainly of 2 to 4 mm (after sieving the solids) and an initial packing density of 780 kg / m³ for the target material. 3 The beads were heat-treated in air at 700°C to give them a 250µm diameter. 2 The specific surface area was measured in g. Next, the surface area was determined by using a nitric acid aqueous solution (0.1N, Merck). TM The volume of the impregnated pores was determined, and the beads were subjected to hydrothermal treatment. The hydrothermal treatment was carried out in a rotary basket autoclave at 200°C for 6.5 hours. The resulting beads were then subjected to a final calcination treatment in air at 950°C for 2 hours. The carrier S2 has a diameter of 71m. 2 The specific surface area per g, the total pore volume of 0.56 ml / g, and the following pore distribution obtained by mercury porosimetry:

[0153] - The volume of mesopores with a diameter greater than or equal to 10 nm and less than 50 nm is 0.35 ml / g, corresponding to 63% of the total pore volume, and their pore distribution is concentrated at 20 nm;

[0154] - The volume of macropores with a diameter greater than or equal to 50 nm and less than 8000 nm is 0.21 ml / g, corresponding to 38% of the total pore volume.

[0155] The carrier S2 exhibited a water absorption volume of 0.54 ml / g. This was achieved by using 8.24 g of nickel nitrate hexahydrate (Sigma-Aldrich). TM An impregnation solution was prepared by diluting 40 g of the support (purity ≥98.5%) in 21.1 ml of distilled water. After dry impregnation of 40 g of support and aging in a moisture-saturated atmosphere for 12 hours, the solid was dried at 120 °C for 12 hours. The catalyst precursor was obtained by using 22.64 g of nickel nitrate (Ni(NO3)2·6H2O, 99.5%, Merck) to form the catalyst precursor. TM A solution diluted in 18.1 ml of distilled water was used to perform a second impregnation step on the catalyst precursor. The solid was then calcined in air at 450 °C for 2 hours. The resulting calcined catalyst is denoted as B. The final metallic composition of the catalyst (expressed as oxides relative to the weight of the dried catalyst) is as follows: NiO = 17.0 ± 0.2 wt% (i.e., Ni content is 13.4 wt%). Catalyst B has a total pore volume of 0.46 ml / g and a pore size of 56 m... 2 Specific surface area per g.

[0156] Example 3: Catalyst C (macroporous catalyst) not based on the present invention

[0157] Commercially available carriers S3 (SA52124, UniSpheres Nor) are available in bead form with diameters of 2 to 4 mm. TM The carrier S3 has an 8m 2 The specific surface area per g, the total pore volume of 0.33 ml / g, and the following pore distribution obtained by mercury intrusion porosimetry:

[0158] - The volume of macropores with a diameter greater than or equal to 50 nm and less than 8000 nm is 0.33 ml / g, corresponding to 100% of the total pore volume.

[0159] The carrier S3 exhibited a water absorption volume of 0.47 ml / g. This was achieved by using 8.24 g of nickel nitrate hexahydrate (Sigma-Aldrich). TMAn impregnation solution was prepared by diluting 40 g of the support (purity ≥ 98.5%) in 18.4 ml of distilled water. After dry impregnation of 40 g of support and aging in a moisture-saturated atmosphere for 12 hours, the solid was dried at 120 °C for 12 hours. The catalyst precursor was obtained by using 22.64 g of nickel nitrate (Ni(NO3)2·6H2O, 99.5%, Merck) to obtain the catalyst precursor. TM The solution prepared by diluting in 15.8 ml of distilled water was used for the second impregnation step. After the steps of dry impregnation of the catalyst precursor and aging in a moisture-saturated atmosphere for 12 hours, the solid was dried at 120 °C for 12 hours. Subsequently, the solid was calcined in air at 450 °C for 2 hours. The calcined catalyst obtained thus is denoted as C. Subsequently, the final metallic composition of the catalyst (expressed as oxides and relative to the weight of the dried catalyst) is as follows: NiO = 17.0 ± 0.2 wt% (i.e., the Ni element content is 13.4 wt%). Catalyst C has a total pore volume of 0.28 ml / g and a pore size of 7 m 2 Specific surface area per g.

[0160] Example 4: Catalyst D (single-peak mesoporous catalyst) not according to the present invention

[0161] Commercially available carrier S4 (SA 6578, NorPro) is available in 5mm diameter extrusion form. TM The carrier S4 has a diameter of 175m. 2 The specific surface area per g, the total pore volume of 0.82 ml / g, and the following pore distribution obtained by mercury intrusion porosimetry:

[0162] - The volume of mesopores with a diameter greater than or equal to 2 nm and less than or equal to 20 nm is 0.82 ml / g, which corresponds to 100% of the total pore volume, and the pore distribution is concentrated at 13 nm.

[0163] The carrier S4 exhibited a water absorption volume of 0.81 ml / g. This was achieved by using 8.24 g of nickel nitrate hexahydrate (Sigma-Aldrich). TM An impregnation solution was prepared by diluting 40 g of the support (purity ≥ 98.5%) in 31.7 ml of distilled water. After dry impregnation of 40 g of support and aging in a moisture-saturated atmosphere for 12 hours, the solid was dried at 120 °C for 12 hours. The catalyst precursor was obtained by using 22.64 g of nickel nitrate (Ni(NO3)2·6H2O, 99.5%, Merck) to obtain the catalyst precursor. TMThe solution prepared by diluting in 27.2 ml of distilled water was used for the second impregnation step. After the steps of dry impregnation of the catalyst precursor and aging in a moisture-saturated atmosphere for 12 hours, the solid was dried at 120 °C for 12 hours. Subsequently, the solid was calcined in air at 450 °C for 2 hours. The calcined catalyst obtained thus is denoted as D. Subsequently, the final metallic composition of the catalyst (expressed as oxides and relative to the weight of the dried catalyst) is as follows: NiO = 17.0 ± 0.2 wt% (i.e., the Ni element content is 13.4 wt%). Catalyst D has a total pore volume of 0.67 ml / g and a pore size of 142 m. 2 Specific surface area per g.

[0164] Example 5: Catalyst E (a catalyst with macropores and small-to-mesopores with a unimodal distribution) not according to the present invention

[0165] Commercially available carrier S5 (SA 6176, NorPro) is available in 1.6mm diameter extruded form. TM The carrier S5 has a capacity of 250m. 2 The specific surface area per g, the total pore volume of 1.05 ml / g, and the following pore distribution obtained by mercury intrusion porosimetry:

[0166] - The volume of mesopores with a diameter greater than or equal to 2 nm and less than or equal to 20 nm is 0.68 ml / g, corresponding to 65% of the total pore volume, and their pore distribution is concentrated at 7 nm.

[0167] - The volume of macropores with a diameter greater than or equal to 50 nm and less than 8000 nm is 0.37 ml / g, corresponding to 35% of the total pore volume.

[0168] The carrier S5 exhibited a water absorption volume of 1.02 ml / g. This was achieved by using 8.24 g of nickel nitrate hexahydrate (Sigma-Aldrich). TM An impregnation solution was prepared by diluting 40 g of the support (purity ≥ 98.5%) in 39.9 ml of distilled water. After dry impregnation of 40 g of support and aging in a moisture-saturated atmosphere for 12 hours, the solid was dried at 120 °C for 12 hours. The catalyst precursor was obtained by using 22.64 g of nickel nitrate (Ni(NO3)2·6H2O, 99.5%, Merck) to obtain the catalyst precursor. TMThe solution prepared by diluting in 34.2 ml of distilled water was used for the second impregnation step. After the steps of dry impregnation of the catalyst precursor and aging in a moisture-saturated atmosphere for 12 hours, the solid was dried at 120 °C for 12 hours. Subsequently, the solid was calcined in air at 450 °C for 2 hours. The calcined catalyst obtained thus is denoted as E. Subsequently, the final metallic composition of the catalyst (expressed as oxides and relative to the weight of the dried catalyst) is as follows: NiO = 17.0 ± 0.2 wt% (i.e., the Ni element content is 13.4 wt%). Catalyst E has a total pore volume of 0.87 ml / g and a pore size of 205 m. 2 Specific surface area per g.

[0169] Example 6: Performance evaluation of catalysts in a refining reactor for desulfurization processes

[0170] The catalytic performance of solid A (according to the invention) and solids B through E (not according to the invention) was evaluated using model feedstocks representing partially desulfurized catalytic cracking gasoline, which was produced by a preliminary step of catalytic hydrodesulfurization and contained 10 wt% 2,3-dimethylbut-2-ene and 70 ppm S (including 42 ppm S from 1-hexamethylenetetramine and 28 ppm S from 3-methylthiophene). The solvent used was heptane.

[0171] In a fixed crossflow reactor, at a total pressure of 1.5 MPa, 270 °C, and HSV = 6 h... -1 The purification reaction was carried out in the presence of 4 ml of catalyst at an H2 / feed volume ratio of 300 Nl / l (HSV = feed volume flow rate / catalyst volume) and 300 Nl / l H2 / feed volume ratio. Prior to the purification reaction, the catalyst was in-situ sulfided at atmospheric pressure in a hydrogen stream containing 15 mol% H2S at 350 °C for 2 hours. Samples were taken at different time intervals and analyzed by gas chromatography to observe the disappearance of reactants and the formation of products.

[0172] The catalytic performance of the catalyst was evaluated by the conversion rates of 3-methylthiophene and 1-hexanethiol.

[0173]

[0174] The conversion of 3-methylthiophene observed using catalyst A was higher than that observed using comparative catalysts B and C. Furthermore, the conversions of 1-hexanethiol and 2,3-dimethylbut-2-ene were essentially equal.

[0175] Compared to catalysts D and E, catalyst A showed equal conversions of 3-methylthiophene and 1-hexanethiol. However, the conversion of 2,3-dimethylbut-2-ene was significantly lower with catalyst A. Therefore, catalyst A is more selective than the comparative catalysts D and E.

[0176] This behavior of the catalyst according to the invention is particularly advantageous when implemented in a hydrodesulfurization process for olefin-containing gasoline, in which the aim is to ensure deep desulfurization and to limit octane number loss due to olefin hydrogenation as much as possible.

Claims

1. A method for treating partially desulfurized sulfur-containing hydrocarbon feedstock produced by a preliminary step of catalytic hydrodesulfurization, said method being carried out at a temperature of 200°C to 400°C, a pressure of 0.2 to 5 MPa, and a time of 0.1 h. -1 Up to 20 h -1 The process is carried out at a space-time velocity in the presence of a catalyst comprising an active phase containing at least one Group VIII metal and a mesoporous-macroporous alumina support with a bimodal mesoporous distribution, wherein the space-time velocity is defined as the volumetric flow rate of the feed at the inlet divided by the volume of the catalyst used, the active phase being free of any Group VIB metal, and wherein: - The volume of mesopores with a diameter greater than or equal to 2 nm and less than 18 nm corresponds to 10% to 30% of the total pore volume of the carrier. - The volume of mesopores with a diameter greater than or equal to 18 nm and less than 50 nm corresponds to 30% to 50% of the total pore volume of the carrier. - The volume of macropores with a diameter greater than or equal to 50 nm and less than 8000 nm corresponds to 30% to 50% of the total pore volume of the carrier.

2. The method of claim 1, wherein the specific surface area of ​​the carrier is 50 to 210 m² / g.

3. The method of any one of claims 1 and 2, wherein the total pore volume of the carrier is 0.7 to 1.3 ml / g.

4. The method of any one of claims 1 and 2, wherein the volume of the mesopores with a diameter greater than or equal to 2 nm and less than 18 nm corresponds to 15% to 25% of the total pore volume of the carrier.

5. The method of any one of claims 1 and 2, wherein the volume of the mesopores with a diameter greater than or equal to 18 nm and less than 50 nm corresponds to 35% to 45% of the total pore volume of the carrier.

6. The method of any one of claims 1 and 2, wherein the volume of macropores with a diameter greater than or equal to 50 nm and less than 8000 nm corresponds to 35% to 50% of the total pore volume of the carrier.

7. The method of any one of claims 1 and 2, wherein the content of group VIII metals in the catalyst, expressed in the form of group VIII elements, is from 5% to 65% by weight relative to the total weight of the catalyst.

8. The method of any one of claims 1 and 2, wherein the group VIII metal is nickel.

9. The method of any one of claims 1 and 2, wherein the pore distribution of mesopores with a diameter greater than or equal to 2 nm and less than 18 nm is concentrated in the numerical range of 10.5 to 14.5 nm.

10. The method of any one of claims 1 and 2, wherein the pore distribution of mesopores with a diameter greater than or equal to 18 nm and less than 50 nm is concentrated in the numerical range of 22 to 28 nm.

11. The method of any one of claims 1 and 2, wherein the specific surface area of ​​the carrier is 70 to 180 m² / g.

12. The method of any one of claims 1 and 2, wherein the carrier is in the form of beads having a diameter of 2 to 4 mm.

13. The method of claim 12, wherein the carrier is obtained according to the following steps: s1) At a temperature of 400°C to 1200°C, aluminum hydroxide or aluminum hydroxide is dehydrated for 0.1 seconds to 5 seconds to obtain aluminum oxide powder; s2) The alumina powder obtained in step s1) is shaped into beads; s3) Alumina beads obtained in step s2) are heat-treated at a temperature of 200°C or higher; s4) Alumina beads obtained at the end of hydrothermal treatment step s3) by impregnation with water or aqueous solution and then retention in an autoclave at a temperature of 100°C to 300°C; s5) Calcine the alumina beads obtained at the end of step s4) at a temperature of 500°C to 820°C.

14. The method of claim 13, wherein in step s1), aluminum hydroxide or aluminum hydroxide is dehydrated for 0.1 seconds to 4 seconds at a temperature of 600°C to 900°C.

15. The method of any one of claims 1 and 2, wherein the partially desulfurized sulfur-containing hydrocarbon feedstock contains less than 100 ppm by weight of sulfur.

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