A method for selective hydrogenation of gasoline in the presence of a catalyst on a mesoporous-macroporous matrix.

Abstract

A method for selectively hydrogenating gasoline containing polyunsaturated compounds and light sulfur compounds is disclosed, wherein gasoline and hydrogen are contacted together with a catalyst comprising a Group VIB metal, a Group VIII metal, and a mesoporous-macroporous alumina matrix having a bimodal mesoporous pore distribution, wherein: - the volume of mesopores having a diameter greater than or equal to 2 nm and less than 18 nm is equivalent to 10-30% by volume of the total pore volume of the matrix; - the volume of mesopores having a diameter greater than or equal to 18 nm and less than 50 nm is equivalent to 30-50% by volume of the total pore volume of the matrix; - the volume of macropores having a diameter greater than or equal to 50 nm and less than 8000 nm is equivalent to 30-50% by volume of the total pore volume of the matrix.

Description

Technical Field

[0001] This invention relates to the field of hydrotreating gasoline fractions, particularly gasoline fractions produced in self-fluidized bed catalytic cracking units. More specifically, this invention relates to the use of catalysts in methods for selectively hydrogenating gasoline and increasing the molecular weight of light thiols, and to methods for selectively hydrogenating polyunsaturated compounds contained in gasoline to monounsaturated compounds, and for increasing the molecular weight of light sulfur-containing compounds by reacting with unsaturated compounds. Existing technology

[0002] Producing gasoline that meets the new environmental standards requires significantly reducing its sulfur content to a value that typically does not exceed 50 ppm, and preferably is below 10 ppm.

[0003] Furthermore, it is known that converted gasoline, and more particularly those produced by autocatalytic cracking (which can account for 30%-50% of the gasoline pool), has high levels of olefins and sulfur.

[0004] For this reason, nearly 90% of the sulfur present in gasoline is attributed to gasoline produced by catalytic cracking, referred to hereinafter as FCC (fluid catalytic cracking) gasoline. Therefore, FCC gasoline constitutes a preferred feedstock for the method of the present invention. More generally, the method according to the invention is applicable to any gasoline fraction containing a certain proportion of dienes, and said gasoline fraction may also contain some lighter compounds belonging to the C3 and C4 fractions.

[0005] Gasoline from cracking units is typically rich in olefins and sulfur, but also in dienes, with diene content reaching up to 5% by weight for gasoline from catalytic cracking. Dienes are unstable compounds that readily polymerize and must generally be removed before these gasolines undergo any treatment (e.g., hydrodesulfurization designed to meet sulfur content specifications). However, this hydrotreating must be selective for dienes, and the hydrogenation of olefins must be limited to restrict hydrogen consumption and octane number loss in the gasoline. Furthermore, as described in patent application EP01077247A1, it is advantageous to convert mercaptans by increasing their molecular weight before the desulfurization step, as this can produce a desulfurized gasoline fraction consisting primarily of olefins with five carbon atoms without loss of octane number through simple distillation. After selective hydrogenation and increasing the molecular weight of the light sulfur-containing compounds, the amount of sulfur present in the feedstock remains unchanged; only the properties of sulfur are altered by the increase in the molecular weight of the light sulfur-containing compounds.

[0006] Furthermore, the diene compounds present in the feedstock are unstable and tend to polymerize to form gums. This gum formation leads to gradual deactivation of the downstream catalyst or gradual blockage of the hydrodesulfurization reactor. Therefore, for industrial applications, it is important to use catalysts that limit polymer formation, i.e., catalysts with low acidity or whose porosity is optimized to promote the continuous extraction of polymer or gum precursors from hydrocarbons in the feedstock, thus ensuring maximum catalyst cycle time.

[0007] Existing technologies show that the pore distribution of a catalyst support can have a beneficial effect on catalytic performance.

[0008] US 6,589,908 discloses a method for preparing a catalyst support that is free of macropores and has a bimodal pore structure within its mesopores, such that the bimodal pores are spaced 1-20 nm apart. This support can be used in numerous catalytic applications, particularly for hydrogenation processes, especially hydrodenitrification.

[0009] US 5,266,300 discloses a method for preparing porous alumina supports for use as catalyst supports in hydrodesulfurization or hydrodemetallization, wherein the supports comprise 0.65-1.30 cm³ of porous alumina. 3 The porous carrier comprises two macropore groups, wherein approximately 2% to 20% of the total pore volume is in the form of macropores with a diameter of 10,000 angstroms to 100,000 angstroms (1,000 to 10,000 nm), approximately 5% to 30% of the total pore volume is in the form of macropores with a diameter of 1,000 angstroms to 10,000 angstroms (100 to 1,000 nm), and approximately 50% to 93% of the total pore volume is in the form of mesopores with a pore size of 30 angstroms to 1,000 angstroms (3 to 100 nm).

[0010] 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 at 2-4 nm, 5-15 nm and 10-40 nm, respectively.

[0011] Document US 7,790,130 discloses alumina for halide removal, which comprises a three-peaked pore structure in which 40-49% of the total pore volume of the support is in the form of pores with a diameter of 15-50 nm.

[0012] Finally, FR 2,895,414 and FR 2,895,415 disclose methods for the selective hydrogenation of polyunsaturated compounds using catalysts with macropores, the volume of which is 10%-40% of the total pore volume.

[0013] However, none of the existing technical documents describe the use of a method for selective hydrogenation of gasoline containing polyunsaturated compounds and light sulfur compounds in the presence of a catalyst comprising a support having bimodal mesoporous pores and a combination of high-medium pore volume and specific macropore volume.

[0014] In this context, one object of the present invention is to provide a method for selectively hydrogenating polyunsaturated compounds, more particularly dienes, in the presence of a supported catalyst, and for increasing the molecular weight of light sulfur-containing compounds, more particularly thiols, with performance in terms of activity and selectivity that is at least as good as, or even better than, methods known in the prior art.

[0015] The applicant has discovered that catalysts based on at least one Group VIB metal and at least one Group VIII metal supported on a mesoporous-macroporous support (the support having bimodal mesoporous pores and a combination of high-medium pore volume and a given macroporous volume) exhibit better activity and selectivity than prior art catalysts in the hydrogenation of dienes, and at least as good as or even better than prior art catalysts, while achieving better conversion of light sulfur-containing compounds than prior art catalysts.

[0016] Specifically, without being constrained by any scientific theory, the use of such a catalyst in the selective hydrogenation of gasoline improves the internal diffusion of reactants and products through the presence of mesopore groups of different sizes. Furthermore, this is particularly relevant when the feedstock contains a large amount of reactive olefins (unsaturated compounds), especially dienes, as is the case with gasoline, which can lead to gum formation. Therefore, the presence of a combination of macropores is especially recommended, as it avoids clogging the catalyst pores.

[0017] Invention Theme

[0018] One subject of the present invention is a method for selectively hydrogenating gasoline containing polyunsaturated compounds and light sulfur compounds, wherein the hydrogenation is carried out at a temperature of 80°C-220°C for 1 hour. -1 -10h -1 A liquid hourly space velocity and a pressure of 0.5-5 MPa allow gasoline and hydrogen to contact the catalyst, and the molar ratio between hydrogen and the diene to be hydrogenated is greater than 1 and less than 100 mol / mol. The catalyst comprises at least one Group VIB metal, at least one Group VIII metal, and a mesoporous-macroporous alumina support with a bimodal mesoporous distribution, wherein:

[0019] - The volume of the mesopores with a diameter greater than or equal to 2 nm and less than 18 nm is equivalent to 10%-30% of the total pore volume of the carrier;

[0020] - The volume of the mesopores with a diameter greater than or equal to 18 nm and less than 50 nm is equivalent to 30%-50% of the total pore volume of the carrier;

[0021] - The volume of macropores with a diameter greater than or equal to 50 nm and less than 8000 nm is equivalent to 30%-50% of the total pore volume of the carrier.

[0022] According to one or more embodiments, the carrier has a size of 50-210m. 2 Specific surface area per g.

[0023] According to one or more embodiments, the carrier has a total pore volume of 0.7-1.3 ml / g.

[0024] According to one or more embodiments, the volume of the mesopore having a diameter greater than or equal to 2 nm and less than 18 nm is equivalent to 15%-25% of the total pore volume of the carrier.

[0025] According to one or more embodiments, the volume of the mesopores having a diameter greater than or equal to 18 nm and less than 50 nm is equivalent to 35%-45% of the total pore volume of the carrier.

[0026] 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 is equivalent to 35%-50% of the total pore volume of the carrier.

[0027] According to one or more embodiments, the content of Group VIB metals in the catalyst, expressed in oxide form, is 1% to 30% by weight relative to the total weight of the catalyst.

[0028] According to one or more embodiments, the content of Group VIII metals in the catalyst, expressed in oxide form, is 1% to 20% by weight relative to the total weight of the catalyst.

[0029] According to one or more embodiments, the molar ratio of the Group VIII metal to the Group VIB metal is 0.3-3 mol / mol.

[0030] According to one or more embodiments, the Group VIII metal is nickel.

[0031] According to one or more embodiments, the Group VIB metal is molybdenum.

[0032] 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 10.5-14.5 nm.

[0033] 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 22-28 nm.

[0034] According to one or more embodiments, the gasoline is catalytic cracking gasoline.

[0035] According to one or more embodiments, the carrier is in the form of beads with a diameter of 2-4 mm.

[0036] According to one or more embodiments, when the carrier is in bead form, the carrier is obtained according to the following steps:

[0037] s1) Aluminum hydroxide or aluminum oxyhydroxide is dehydrated at a temperature of 400℃-1200℃, preferably 600℃-900℃, for 0.1 seconds to 5 seconds, preferably 0.1 seconds to 4 seconds, to obtain aluminum oxide powder;

[0038] s2) The alumina powder obtained in step s1) is formed into beads;

[0039] s3) Heat-treat the alumina beads obtained in step s2) at a temperature of 200°C or higher;

[0040] s4) The alumina beads obtained at the end of step s3) are subjected to hydrothermal treatment by immersion in water or aqueous solution and then staying in an autoclave at a temperature of 100℃-300℃.

[0041] s5) Calcine the alumina beads obtained at the end of step s4) at a temperature of 500℃-820℃.

[0042] According to one or more embodiments, the catalyst does not contain phosphorus. Invention Details

[0044] 1. Definition

[0045] 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.

[0046] BET surface area was measured by nitrogen physical adsorption according to standard ASTM D3663-03 (the method described in "Adsorption by Powders & Porous Solids: Principles, Methodology and Applications" by Rouquerol F., Rouquerol J. and Singh K., Academic Press, 1999).

[0047] In this specification, in accordance with IUPAC convention, "micropore" should be understood as a pore with a diameter of less than 2 nm, i.e., 0.002 μm; "mesopore" should be understood as a pore with a diameter of greater than 2 nm, i.e., 0.002 μm and less than 50 nm, i.e., 0.05 μm; and "macropore" should be understood as a pore with a diameter of greater than or equal to 50 nm, i.e., 0.05 μm.

[0048] In the following description of the invention, the “total pore volume” of alumina or catalyst should be understood as the volume measured by mercury intrusion porosimetry under a maximum pressure of 4000 bar (400 MPa), a surface tension of 484 dynes / cm, and a contact angle of 140°, according to standard ASTM D4284-83. Following the recommendation on pages 1050-1055 of the publication “Techniques del′ingénieur, traité analyze et caractérisation” [Techniques of the Engineer, Analysis and Characterization Treatise] by Jean Charpin and Bernard Rasneur, the wetting angle is taken as 140°.

[0049] For better accuracy, the total pore volume values ​​given below in ml / g are equivalent to the total mercury volume in ml / g measured on the sample (total pore volume measured by mercury porosimetry) minus the mercury volume in ml / g measured on the same sample at a pressure equivalent to 30 psi (approximately 0.2 MPa).

[0050] According to standard ASTM D4284-83, the volume of macropores and mesopores is 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°.

[0051] 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 considered that above this value, mercury penetrates into the pores of the sample.

[0052] The macropore volume of the catalyst is defined as the cumulative volume of mercury introduced under pressure of 0.2 MPa-30 MPa, which is equivalent to the volume contained in pores with an apparent diameter greater than 50 nm.

[0053] The mesopore volume of the catalyst is defined as the cumulative volume of mercury introduced under a pressure of 30 MPa-400 MPa, equivalent to the volume contained in a pore with an apparent diameter of 2-50 nm.

[0054] 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.

[0055] The contents of Group VIII and Group VIB metals were measured by X-ray fluorescence method.

[0056] 2. Description

[0057] catalyst

[0058] In the context of the selective hydrogenation method according to the invention, the catalyst used comprises an active phase formed of at least one Group VIB metal and at least one Group VIII metal.

[0059] The Group VIB metals present in the active phase of the catalyst are preferably selected from molybdenum and tungsten, more preferably from molybdenum. The Group VIII metals present in the active phase of the catalyst are preferably selected from cobalt, nickel, and mixtures of these two elements, more preferably from nickel.

[0060] Preferably, the active phase is composed of molybdenum and nickel.

[0061] The total content of the Group VIII metal relative to the total weight of the catalyst is typically 1%-20% by weight (expressed as oxides of the Group VIII metal), preferably 2%-15% by weight, and more preferably 3%-13% by weight relative to the total weight of the catalyst. When the metal is cobalt or nickel, the metal content is expressed as CoO or NiO, respectively.

[0062] The content of the Group VIB metal relative to the total weight of the catalyst is typically 1% to 30% by weight (expressed as an oxide of the Group VIB metal), preferably 5% to 20% by weight, and even more preferably 8% to 15% by weight relative to the total weight of the catalyst. When the metal is molybdenum or tungsten, the metal content is expressed as MoO3 or WO3, respectively.

[0063] The molar ratio between the Group VIII metal and the Group VIB metal is advantageously 0.3-3 mol / mol, preferably 0.4-2.5 mol / mol, and most preferably 0.5-2 mol / mol.

[0064] The Group VIII metal is preferably nickel.

[0065] The preferred Group VIB metal is molybdenum.

[0066] Preferably, the catalyst is phosphorus-free.

[0067] The catalyst typically has a concentration of 50-200 mg / m³. 2 / g, preferably 60-170m 2 / g, preferably 70-130m 2 Specific surface area per g.

[0068] The pore volume of the catalyst is typically 0.5 ml / g-1.3 ml / g, preferably 0.6 ml / g-1.1 ml / g.

[0069] Alumina carrier

[0070] In the context of the selective hydrogenation method according to the invention, the alumina support for the catalyst is a macroporous-mesoporous alumina support comprising a bimodal mesoporous distribution, wherein:

[0071] - The volume of the mesopores with a diameter greater than or equal to 2 nm and less than 18 nm is equivalent to 10%-30% of the total pore volume of the carrier;

[0072] - The volume of the mesopores with a diameter greater than or equal to 18 nm and less than 50 nm is equivalent to 30%-50% of the total pore volume of the carrier;

[0073] - The volume of macropores with a diameter greater than or equal to 50 nm and less than 8000 nm is equivalent to 30%-50% of the total pore volume of the carrier.

[0074] Preferably, the volume of the mesopores in the carrier having a diameter greater than or equal to 2 nm and less than 18 nm is equivalent to 15%-25% of the total pore volume of the carrier.

[0075] Preferably, the volume of the mesopores in the carrier having a diameter greater than or equal to 18 nm and less than 50 nm is equivalent to 35%-45% of the total pore volume of the carrier.

[0076] Preferably, the volume of the macropores in the carrier having a diameter greater than or equal to 50 nm and less than 8000 nm is equivalent to 35%-50% of the total pore volume of the carrier.

[0077] In one embodiment of the invention, the pore distribution of the mesopores having a diameter greater than or equal to 2 nm and less than 18 nm is concentrated in the numerical range of 10.5-14.5 nm, preferably 12-13 nm.

[0078] In one embodiment of the invention, the pore distribution of the mesopores having a diameter greater than or equal to 18 nm and less than 50 nm is concentrated in the numerical range of 22-28 nm, preferably 23-27 nm.

[0079] The carrier typically has a diameter of 50-210m. 2 / g, preferably 70-180m 2 / g, preferably 70-160m 2 Specific surface area per g.

[0080] The pore volume of the carrier is typically 0.7 ml / g-1.3 ml / g, preferably 0.8 ml / g-1.2 ml / g.

[0081] Advantageously, the carrier is in the form of beads having a diameter of 0.8-10 mm, preferably 1-5 mm, more preferably 2-4 mm.

[0082] Preferably, the catalyst consists of an active phase composed of molybdenum and nickel and a mesoporous-macroporous alumina support with a bimodal mesoporous distribution, wherein:

[0083] - The volume of the mesopores with a diameter greater than or equal to 2 nm and less than 18 nm is equivalent to 10%-30% of the total pore volume of the carrier;

[0084] - The volume of the mesopores with a diameter greater than or equal to 18 nm and less than 50 nm is equivalent to 30%-50% of the total pore volume of the carrier;

[0085] - The volume of macropores with a diameter greater than or equal to 50 nm and less than 8000 nm is equivalent to 30%-50% of the total pore volume of the carrier.

[0086] Methods for preparing carriers

[0087] The alumina support for the catalyst used in the context of the selective hydrogenation method according to the invention can be synthesized by any method known to those skilled in the art.

[0088] According to a preferred embodiment, the alumina support used according to the present invention is in the form of beads. According to this preferred embodiment, the preparation of the support includes the following steps:

[0089] s1) Aluminum hydroxide or aluminum hydroxide is dehydrated at a temperature of 400℃-1200℃, preferably 600℃-900℃, for 0.1 seconds to 5 seconds, preferably 0.1 seconds to 4 seconds, to obtain aluminum oxide powder;

[0090] s2) The alumina powder obtained in step s1) is formed into beads;

[0091] s3) Heat-treat the beads obtained in step s2) at a temperature of 200°C or higher;

[0092] 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 kept in an autoclave at a temperature of 100°C-300°C, preferably 150°C-250°C.

[0093] s5) Calcine the alumina beads obtained at the end of step s4) at a temperature of 500℃-820℃.

[0094] Steps s1 through s5 are described in detail below.

[0095] Step s1)

[0096] According to step s1), aluminum hydroxide or aluminum hydroxyaluminate is dehydrated at a temperature of 400°C-1200°C, preferably 600°C-900°C, for 0.1 seconds to 5 seconds, preferably 0.1 seconds to 4 seconds, to obtain alumina powder. Aluminum hydroxide can be selected from hydrargillite, gibbsite, or gibbsite. Aluminum hydroxyaluminate can be selected from boehmite or diaspore. Preferably, step s1) is performed using gibbsite.

[0097] Typically, step s1) is carried out in the presence of a hot air stream, such as dry or humid air, which can quickly remove and entrain evaporated water.

[0098] Typically, activated alumina powder obtained by dehydrating aluminum hydroxide or aluminum hydroxide is ground to a particle size of 10-200 μm.

[0099] Typically, the activated alumina powder obtained after dehydration of aluminum hydroxide or aluminum hydroxide is washed with water or an acidic aqueous solution. When performing the washing step with an acidic aqueous solution, any inorganic or organic acid can be used. For inorganic acids, nitric acid, hydrochloric acid, perchloric acid, or sulfuric acid are preferred, and for organic acids, carboxylic acids (formic acid, acetic acid, or malonic acid), sulfonic acids (p-toluenesulfonic acid), or sulfate esters (dodecyl sulfate) are preferred.

[0100] Step s2)

[0101] According to step s2), the alumina powder obtained at the end of step s1) is shaped.

[0102] The alumina powder is shaped to obtain beads; this is called granulation and is typically carried out using rotary techniques, such as rotary granulators or rotary drums. This type of method yields beads with controlled diameter and pore distribution, which are usually formed during the agglomeration step.

[0103] Pores can be formed 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 is to mix one or more compounds with the alumina powder before or during the agglomeration step; these compounds are called pore-forming compounds. Heating causes these compounds to dissolve, thereby forming pores in the beads. Pore-forming compounds used include, for example, wood flour, charcoal, activated carbon, carbon black, sulfur, tar, plastics or plastic emulsions such as polyvinyl chloride, polyvinyl alcohol, naphthalene, etc. The amount of pore-forming compound added is 500-1100 kg / m³ to obtain the initial green filling density. 3 The preferred strength is 700-950 kg / m³. 3 The required volume of beads with a diameter of 0.8-10 mm, preferably 1-5 mm, or even more preferably 2-4 mm, is determined by the desired size. Beads can be selected using a sieving method based on the required particle size.

[0104] Step s3)

[0105] According to step s3), the alumina powder obtained at the end of step s2) and formed into beads is heat-treated at a temperature of 200°C or higher, preferably 200°C-1200°C, preferably 300°C-900°C, and most preferably 400°C-750°C, for a duration typically 1-24 hours, preferably 1-6 hours. The beads obtained in this intermediate step have a particle size of 50-420 μm. 2 / g, preferably 60-350m 2 / g, or even better, 80-300m 2 Specific surface area per g.

[0106] Step s4)

[0107] According to step s4), the alumina beads obtained at the end of step s3) are subjected to hydrothermal treatment by immersion in water or an aqueous solution, preferably an acidic aqueous solution, and then kept in an autoclave at a temperature of 100℃-300℃, preferably 150℃-250℃.

[0108] Hydrothermal treatment is typically carried out at temperatures between 100°C and 300°C, preferably between 150°C and 250°C, for a duration exceeding 45 minutes, preferably 1-24 hours, and very preferably 1.5-12 hours. The hydrothermal treatment is usually performed 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, wherein the solution of the weak acid has a pH less than 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 with aluminum ions, preferably containing 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 having the general formula: R-COO. - Compounds containing anions (such as formate and acetate).

[0109] Step s5)

[0110] According to step s5), the alumina beads obtained at the end of step s4) are calcined at a temperature of 500℃-820℃, preferably 550℃-750℃, typically for 1-24 hours, preferably 1-6 hours. At the end of this step, the obtained alumina beads have a particle size of 50-210 μm. 2 / g, preferably 70-180m 2 / g, or even more preferably 70-160m 2 Specific surface area per g.

[0111] Methods for preparing catalysts

[0112] The catalyst used in the context of the selective hydrogenation method according to the invention can be prepared by any technique known to those skilled in the art, particularly by impregnating a selected support with Group VIII and Group VIB elements.

[0113] For example, impregnation can be carried out according to methods known to those skilled in the art as dry impregnation, wherein only a certain amount of the desired element in the form of a soluble salt is introduced into a selected solvent (e.g., demineralized water) to fill the pores of the support as precisely as possible. Precursors of active phases based on Group VIII metals and precursors of active phases based on Group VIB metals can be introduced simultaneously or sequentially. Impregnation of each precursor can advantageously be carried out at least twice. Thus, various precursors can advantageously be impregnated sequentially with different numbers of impregnations and aging processes. A precursor can also be impregnated several times. The support thus filled with solution is aged at a temperature below 50°C, preferably at ambient temperature, for 0.5-12 hours, preferably 0.5-6 hours, and even more preferably 0.5-3 hours.

[0114] After introducing the precursor of the active phase, the catalyst precursor is activated. The purpose of this treatment is usually to convert the molecular precursor of the element into the oxidized phase. In this case, it is an oxidation treatment, but the catalyst can also be simply dried.

[0115] In the case of drying, the catalyst precursor is dried at a temperature of 50°C-200°C, preferably 70°C-180°C, typically for 0.5-12 hours, and even more preferably 0.5-5 hours. The drying step is advantageously carried out in a crossflow bed using hot air or any other hot gas. Preferably, when drying is carried out in a crossflow bed, the gas used is air or an inert gas, such as argon or nitrogen. Very preferably, drying is carried out in a crossflow bed in the presence of air.

[0116] In the case of oxidation treatment (also known as calcination), the treatment is typically carried out in air or dilute oxygen, and the treatment temperature is typically 200°C-550°C, preferably 300°C-500°C, advantageously lasting for a duration typically 0.5-24 hours, preferably 0.5-12 hours, and even more preferably 0.5-10 hours. The oxidation treatment step is advantageously carried out in a crossflow bed using air or any other hot gas. Preferably, when the oxidation treatment is carried out in a crossflow bed, the gas used is air or an inert gas, such as argon or nitrogen. Very preferably, the oxidation treatment is carried out in a crossflow bed in the presence of air.

[0117] For example, when the Group VIII element is nickel and the Group VIB element is molybdenum, the molybdenum and nickel metal salts that can be used in the catalyst preparation process are, for example, nickel nitrate and ammonium heptamolybdate. Any other salts known to those skilled in the art can also be used, which have sufficient solubility and can decompose during the activation process. Advantageously, drying and oxidation treatments are performed in the catalyst preparation process.

[0118] Prior to its use as a hydrotreating catalyst, the dried or optionally calcined catalyst is advantageously subjected to a sulfidation step (activation stage). This activation stage is carried out by methods well known to those skilled in the art, advantageously in the presence of hydrogen and hydrogen sulfide under a sulfur-reducing atmosphere. Hydrogen sulfide can be used directly or generated by a sulfiding agent (e.g., dimethyl disulfide).

[0119] The catalyst is preferably used at least partially in its sulfidated form. The introduction of sulfur can occur before or after any activation step (i.e., drying or calcination). Sulfur or sulfur-containing compounds can be introduced in situ, i.e., outside the reactor used in the method according to the invention, or in situ, i.e., within the reactor used in the method according to the invention. In the first case, situ sulfidation is characterized by a final passivation step. In fact, the sulfide phase is highly reactive relative to ambient air (due to self-heating properties resulting from oxidation), prohibiting subsequent treatment without additional treatments designed to limit this reactivity. Among commercially available situ sulfidation methods, TOTSUCAT from Eurecat can be mentioned. TM Methods (EP 0 564 317 B1 and EP 0 707 890 B1) and XPresS from Tricat TM Method (Patent US-A-5 958 816). In the second case (in-situ sulfidation), the catalyst is preferably reduced under the conditions described above, and then sulfided by passing it through a feedstock containing at least one sulfur-containing compound, which, once decomposed, leads to the fixation of sulfur on the catalyst. The feedstock can be gaseous or liquid, such as hydrogen gas containing H2S, or a liquid containing at least one sulfur-containing compound.

[0120] Selective hydrogenation method

[0121] This invention relates to a method for processing gasoline containing any type of compound family, particularly dienes, monoolefins, and sulfur-containing compounds in the form of thiols and light sulfides. The invention is particularly applicable to the conversion of gasoline, especially gasoline produced by autocatalytic cracking, fluid catalytic cracking (FCC), coking, viscous reduction cracking, or pyrolysis. Preferably, the feedstock is gasoline from a catalytic cracking unit. The feedstocks suitable for this invention typically have a boiling point of 0°C–280°C. These feedstocks may also contain hydrocarbons having 3 or 4 carbon atoms.

[0122] For example, gasoline produced by an autocatalytic cracking (FCC) unit typically contains 0.5 wt%–5 wt% dienes, 20 wt%–50 wt% monoolefins, and 10 wt ppm–0.5 wt% sulfur, and usually contains less than 300 ppm thiols. Thiols are generally concentrated in the lighter fractions of gasoline, and more particularly in fractions with boiling points below 120°C.

[0123] The gasoline processing described in the selective hydrogenation method of this invention mainly includes:

[0124] - Selective hydrogenation of dienes to mono-olefins;

[0125] - By reacting with monoolefins, saturated light sulfur-containing compounds, mainly thiols, are converted into heavier sulfides or thiols;

[0126] -Isomerize monoolefin compounds with C=C double bonds in the external position to their isomers with C=C double bonds in the internal position.

[0127] The following example illustrates the reaction of hydrogenating a diene to a mono-olefin using the conversion of 1,3-pentadiene (an unstable compound that can be readily hydrogenated to 2-pentene). However, an attempt is made to limit the side reaction of mono-olefin hydrogenation, which, in the examples below, leads to the formation of n-pentane.

[0128]

[0129] The sulfur-containing compounds targeted for conversion are primarily thiols. The main reactions for converting thiols involve thioetherification between mono-olefins and thiols. This reaction is illustrated below by adding propan-2-thiol to 2-pentene to form propylpentyl thioether.

[0130]

[0131] In the presence of hydrogen, the conversion of sulfur-containing compounds may also involve the formation of an intermediate, H₂S, which can then add to unsaturated compounds present in the starting material. However, under preferred reaction conditions, this route is rare.

[0132] Besides thiols, compounds that may be converted in this way and become heavier are sulfides, mainly CS2, COS, tetrahydrothiophene, and methyltetrahydrothiophene.

[0133] In some cases, reactions can be observed in which the molecular weight of light nitrogen-containing compounds, mainly nitriles, pyrroles and their derivatives, increases.

[0134] According to the present invention, the catalyst can also isomerize monoolefin compounds having C=C double bonds at external positions to their isomers having C=C double bonds at internal positions.

[0135] The reaction is illustrated below by isomerizing 1-hexene to 2-hexene or 3-hexene.

[0136]

[0137] In the selective hydrogenation method according to the invention, the feedstock to be treated is mixed with hydrogen before contact with the catalyst. The amount of hydrogen injected is such that the molar ratio between hydrogen and the diene to be hydrogenated is greater than 1 (stoichiometry) and less than 100, preferably 1-10 mol / mol. Too much hydrogen will result in strong hydrogenation of the monoolefin, thereby reducing the octane number of the gasoline. Typically, all feedstock is injected at the reactor inlet. However, in some cases, it may be advantageous to inject part or all of the feedstock between two consecutive catalytic beds placed in the reactor. This embodiment is particularly suitable for continuing to operate the reactor if the reactor inlet is clogged with deposits of polymers, particles, or gums present in the feedstock.

[0138] A mixture of gasoline and hydrogen is brought into contact with a catalyst at a temperature of 80°C-220°C, preferably 90°C-200°C, wherein the liquid hourly space velocity (LHSV) is 1 h⁻¹. -1 -10h -1 The liquid hourly space velocity (LHSV) is the number of liters of feed per liter of catalyst per hour (L / L·h). The pressure is adjusted so that the reaction mixture is mainly in liquid form in the reactor. This pressure is 0.5 MPa-5 MPa, preferably 1-4 MPa.

[0139] Gasoline treated under the above conditions has reduced content of dienes and thiols. Typically, the produced gasoline contains less than 1% by weight of dienes, preferably less than 0.5% by weight. Generally, more than 50% of light sulfur-containing compounds with boiling points lower than thiophene's (84°C) are converted. Therefore, the light fraction can be separated from the gasoline by distillation and fed directly into the gasoline pool without additional hydrodesulfurization treatment. The light fraction of gasoline typically has a final boiling point below 120°C, preferably below 100°C, and most preferably below 80°C.

[0140] The selective hydrogenation method according to the invention is particularly suitable for implementation in the context of the desulfurization method described in patent application EP 1 077 247.

[0141] The subject of this invention also includes a method for desulfurizing gasoline containing sulfur compounds, comprising at least the following steps:

[0142] a) The selective hydrogenation step of the above method;

[0143] b) The step of separating the gasoline obtained in step a) into two fractions, the fractions comprising light gasoline and heavy gasoline respectively;

[0144] c) A hydrodesulfurization step on a catalyst of the heavy gasoline separated in step b), which can at least partially decompose the sulfur-containing compounds into H2S.

[0145] Separation step b) is preferably carried out by a conventional distillation column, also known as a splitter. This distillation column must be able to separate the light fraction of gasoline containing less than 10 ppm by weight of sulfur.

[0146] The column is typically operated at a pressure of 0.1-2 MPa, preferably 0.2-1 MPa. The theoretical plate number of the separation column is typically 10-100, preferably 20-60. The reflux ratio is typically less than 1, preferably less than 0.8, and is expressed as the ratio of the liquid flow rate in the column to the distillate flow rate (expressed in kg / h).

[0147] The light gasoline obtained at the end of the separation typically contains at least all of the C5 olefins (preferably C5 compounds) and at least 20% of the C6 olefins. Typically, this light fraction has a sulfur content of less than 10 ppm by weight, meaning that no additional hydrodesulfurization step is required before it can be used as fuel.

[0148] Desulfurization step c) is preferably a hydrodesulfurization step performed by passing heavy gasoline through a catalyst containing at least one Group VIII element and / or at least one Group VIB element, at a temperature of about 210°C to about 350°C, preferably 220°C to 320°C, in the presence of hydrogen and at a pressure of typically about 1 to about 4 MPa, preferably 1.5 to 3 MPa. The liquid hourly space velocity is about 1 to about 20 h⁻¹. -1 (Expressed as liquid volume per hour per volume of catalyst), preferably 1-10 h -1 The optimal time is 3-8 hours. -1 The H2 / raw material ratio is 100-600 Nl / l, preferably 300-600 Nl / l.

[0149] The content of Group VIII metals, expressed as oxides, is typically 0.5 wt% to 15 wt% relative to the weight of the catalyst, preferably 1 wt% to 10 wt%. The content of Group VIB metals, expressed as oxides, is typically 1.5 wt% to 60 wt% relative to the weight of the catalyst, preferably 3 wt% to 50 wt%.

[0150] Group VIII elements (if present) are preferably cobalt, and Group VIB elements (if present) are typically molybdenum or tungsten. Combinations such as cobalt-molybdenum are preferred. The catalyst support is typically a porous solid, such as alumina, silica-alumina, or other porous solids, such as magnesium oxide, silica, or titanium oxide, alone or as a mixture with alumina or silica-alumina. To minimize the hydrogenation of olefins present in heavy gasoline, it is advantageous to use a catalyst in which the density of the Group VIB metal, expressed as a weight % (by weight relative to the total weight of the catalyst) per unit specific surface area in the form of oxides of the Group VIB metal, is greater than 0.07, preferably greater than 0.12. The catalyst according to step c) preferably has a density of less than 250 m². 2 / g, more preferably less than 230m 2 / g, preferably less than 190m 2 Specific surface area per g.

[0151] The deposition of the metal on the support is achieved by any method known to those skilled in the art, such as dry impregnation or by using an excess solution containing the metal precursor. The impregnation solution is chosen to dissolve the metal precursor at the desired concentration. For example, in the case of synthesizing a CoMo catalyst, the molybdenum precursor may be molybdenum oxide or ammonium heptamolybdate, while the cobalt precursor may be, for example, cobalt nitrate, cobalt hydroxide, or cobalt carbonate. The precursor is typically dissolved in a medium that allows it to dissolve at the desired concentration.

[0152] After introducing one or more elements and optionally shaping the catalyst, the catalyst is activated in a first step. This activation may correspond to oxidation followed by reduction, direct reduction, or calcination alone. The calcination step is typically carried out under an air stream at a temperature of about 100°C to about 600°C, preferably 200°C to 450°C. The reduction step is carried out under conditions capable of converting at least a portion of the oxidized form of the base metal into the metal. Typically, it involves treating the catalyst under a hydrogen stream at a temperature preferably at least equal to 300°C. This reduction may also be carried out in part by a chemical reducing agent.

[0153] The catalyst used in step c) is preferably used at least partially in its sulfide form. The introduction of sulfur can occur before or after any activation step (i.e., calcination or reduction step). Sulfur or sulfur-containing compounds can be introduced in situ, i.e., outside the hydrodesulfurization reactor, or in situ, i.e., within the hydrodesulfurization reactor. In the first case, situ sulfidation is characterized by the final passivation step. Indeed, the sulfide phase is highly reactive relative to ambient air (due to its self-heating properties from oxidation), prohibiting subsequent treatment without additional treatments designed to limit this reactivity. Among commercially available situ sulfidation methods, TOTSUCAT from Eurecat is worth mentioning. TM Methods (EP 0 564 317 B1 and EP 0 707 890 B1) and XPresS from Tricat TM Method (Patent US-A-5 958 816). In the second case (in-situ sulfidation), the catalyst is preferably reduced under the conditions described above, and then sulfided by passing it through a feedstock containing at least one sulfur-containing compound, which, once decomposed, leads to the fixation of sulfur on the catalyst. The feedstock can be gaseous or liquid, such as hydrogen gas containing H2S, or a liquid containing at least one sulfur-containing compound. Example

[0154] Example 1: Catalyst A (according to the present invention)

[0155] The support S1 for catalyst A is made of gibbsite ( Merck TM The alumina powder was obtained by dehydration. The temperature was set to 800°C, and the contact time between the material to be dehydrated and the dry air stream was 1 second. The obtained alumina powder was ground to a particle size of 10-200 μm and then washed three times with distilled water at twice the volume of the powder used. The alumina was then processed with carbon black (N990). In the presence of ), a disc granulator (GRELBEX) equipped with a conical cylindrical disc is used. TM P30) shapes the alumina powder at a 30° angle and a 40 rpm rotation speed to obtain beads with a diameter mainly of 2-4 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. The beads were heat-treated in air at 720°C to give them a density of 200 μm. 2 The specific surface area is / g. Then, by using a nitric acid aqueous solution (0.1N, Merck) TMThe volume of the impregnated pores was determined, and the beads were subjected to hydrothermal treatment. This hydrothermal treatment was carried out at 200°C in a rotary basket autoclave 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 141 μm. 2 The specific surface area per g, the total pore volume of 0.97 ml / g, and the following pore distribution obtained by mercury intrusion porosimetry:

[0156] - The mesopore volume with a diameter greater than or equal to 2 nm and less than 18 nm is 0.15 ml / g, which is equivalent to 15% of the total pore volume, and its pore distribution is concentrated at 13 nm;

[0157] - The mesopore volume with a diameter greater than or equal to 18 nm and less than 50 nm is 0.43 ml / g, which is equivalent to 44% of the total pore volume, and its pore distribution is concentrated at 26 nm;

[0158] - The volume of macropores with a diameter greater than or equal to 50 nm and less than 8000 nm is 0.39 ml / g, which is equivalent to 40% of the total pore volume.

[0159] The water absorption volume of carrier S1 is 0.95 ml / g. This is achieved by adding 6.07 g of ammonium heptamolybdate (Mo7(NH4)6O). 24 ·4H2O, 99.98%, Merck TM ), 17.43g of nickel nitrate (Ni(NO3)2·6H2O, 99.5%, Merck) TM The impregnation solution was prepared by diluting the solid in 36.2 ml of distilled water. After dry impregnation of 40 g of the support 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 obtained catalyst A contained 9.1 wt% NiO and 10.0 wt% MoO3, with a Ni / Mo molar ratio of 1.75. Catalyst A had a total pore volume of 0.83 ml / g and a pore size of 103 m³ / g. 2 Specific surface area per g.

[0160] Example 2: Catalyst B (macro-mesoporous catalyst with macro-mesoporous unimodal distribution) not based on the present invention

[0161] The support S2 for catalyst B is made of gibbsite ( Merck TM The activated alumina powder is obtained by dehydration. The temperature is set to 800°C, and the contact time between the material to be dehydrated and the dry air stream is 1 second. The obtained activated alumina powder is ground to a particle size of 10-200 μm and then washed three times with distilled water at twice the volume of the powder used. It is then processed using a disc granulator (GRELBEX) equipped with a conical cylindrical disc.TM P30) The activated alumina powder is shaped at an angle of 30° and a rotation speed of 40 rpm, thereby (after sieving the solids) obtaining a diameter mainly of 2-4 mm and a weight of 780 kg / m³. 3 The beads were prepared with the original filling density of the target material. The beads were then heat-treated in air at 700°C to achieve a density of 250 μm. 2 The specific surface area is / g. Then, 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. This hydrothermal treatment was carried out at 200°C in a rotary basket autoclave 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:

[0162] - The mesopore volume with a diameter greater than or equal to 10 nm and less than 50 nm is 0.35 ml / g, which is equivalent to 63% of the total pore volume, and its pore distribution is concentrated at 20 nm;

[0163] - The macropore volume with a diameter greater than or equal to 50 nm and less than 8000 nm is 0.21 ml / g, which is equivalent to 38% of the total pore volume.

[0164] The water absorption volume of carrier S2 is 0.54 ml / g. This is achieved by adding 2.76 g of ammonium heptamolybdate (Mo7(NH4)6O). 24 ·4H2O, 99.98%, Merck TM ), 8.80g of nickel nitrate (Ni(NO3)2·6H2O, 99.5%, Merck) TM The impregnation solution was prepared by diluting 3.18 g of ammonium heptamolybdate (Mo7(NH4)6O) in 20.7 ml of distilled water. After dry impregnation of 40 g of the carrier and aging in a moisture-saturated atmosphere for 12 hours, the solid was dried at 120 °C for 12 hours. 24 ·4H2O, 99.98%, Merck TM 7.69g of nickel nitrate (Ni(NO3)2·6H2O, 99.5%), Merck TMThe solution prepared by diluting in 18.8 ml of distilled water was used for the second impregnation step. After dry impregnation of 40 g of the support and aging in a moisture-saturated atmosphere for 12 hours, the solid was dried at 120 °C for 12 hours. Then, the solid was calcined in air at 450 °C for 2 hours. The obtained catalyst B contained 8.9 wt% NiO and 10.3 wt% MoO3, with a Ni / Mo molar ratio of 1.67. Catalyst B had a total pore volume of 0.45 ml / g and a pore size of 59 m... 2 Specific surface area per g.

[0165] Example 3: Catalyst C (macroporous catalyst) not based on the present invention

[0166] Commercial carriers S3 (SA52124) are available in bead form with a diameter of 2-4 mm. NorPro). Carrier S3 has 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 porosimetry:

[0167] - The macropore volume with a diameter greater than or equal to 50 nm and less than 8000 nm is 0.33 ml / g, which is equivalent to 100% of the total pore volume.

[0168] The water absorption volume of carrier S3 is 0.47 ml / g. This is achieved by adding 2.76 g of ammonium heptamolybdate (Mo7(NH4)6O). 24 ·4H2O, 99.98%, Merck TM ), 8.80g of nickel nitrate (Ni(NO3)2·6H2O, 99.5%, Merck) TM The impregnation solution was prepared by diluting 3.18 g of ammonium heptamolybdate (Mo7(NH4)6O) in 18 ml of distilled water. After dry impregnation of 40 g of the carrier and aging in a moisture-saturated atmosphere for 12 hours, the solid was dried at 120 °C for 12 hours. 24 ·4H2O, 99.98%, Merck TM 7.69g of nickel nitrate (Ni(NO3)2·6H2O, 99.5%), Merck TM The solution prepared by diluting in 16.4 ml of distilled water was used for the second impregnation step. After dry impregnation of 40 g of the support and aging in a moisture-saturated atmosphere for 12 hours, the solid was dried at 120 °C for 12 hours. Then, the solid was calcined in air at 450 °C for 2 hours. Catalyst C contains 8.9 wt% NiO and 10.3 wt% MoO3, with a Ni / Mo molar ratio of 1.68. Catalyst C has a total pore volume of 0.23 ml / g and a pore size of 4 m... 2 Specific surface area per g.

[0169] Example 4: Catalyst D (single-peak mesoporous catalyst) not according to the present invention

[0170] Commercial carriers S4 (SA 6578), available in extrusion form with a diameter of 5 mm, are offered by NorPro. 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 porosimetry:

[0171] - 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 is equivalent to 100% of the total pore volume, and the pore distribution is concentrated at 13 nm.

[0172] The water absorption volume of carrier S4 is 0.81 ml / g. This is achieved by adding 6.06 g of ammonium heptamolybdate (Mo7(NH4)6O). 24 ·4H2O, 99.98%, Merck TM ), 17.40g of nickel nitrate (Ni(NO3)2·6H2O, 99.5%, Merck) TM The impregnation solution was prepared by diluting the solid in 30.7 ml of distilled water. After dry impregnation of 40 g of the support and aging in a moisture-saturated atmosphere for 12 hours, the solid was dried at 120 °C for 12 hours. Then, the solid was calcined in air at 450 °C for 2 hours. The obtained catalyst D contained 9.0 wt% NiO and 10.0 wt% MoO3, with a Ni / Mo molar ratio of 1.73. Catalyst D had a total pore volume of 0.74 ml / g and a pore size of 127 m³ / g. 2 Specific surface area per g.

[0173] Example 5: Catalyst E (with a single-peak distribution of macropores and mesopores) not according to the present invention

[0174] Commercial carriers S5 (SA 6176, NorPro) are available in extrusion form with a diameter of 1.6 mm. 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 porosimetry:

[0175] - 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, which is equivalent to 65% of the total pore volume, and the pore distribution is concentrated at 7 nm;

[0176] - The macropore volume with a diameter greater than or equal to 50 nm and less than 8000 nm is 0.37 ml / g, which is equivalent to 35% of the total pore volume.

[0177] The water absorption volume of carrier S5 is 1.02 ml / g. This is achieved by using 6.00 g of ammonium heptamolybdate (Mo7(NH4)6O). 24 ·4H2O, 99.98%, Merck TM ), 17.40g of nickel nitrate (Ni(NO3)2·6H2O, 99.5%, Merck) TM The impregnation solution was prepared by diluting the solid in 39.1 ml of distilled water. After drying and impregnating 40 g of the support and aging it in a moisture-saturated atmosphere for 12 hours, the solid was dried at 120 °C for 12 hours. Then, the solid was calcined in air at 450 °C for 2 hours. Catalyst E contains 9.0 wt% NiO and 9.9 wt% MoO3, with a Ni / Mo molar ratio of 1.75. Catalyst E has a total pore volume of 0.84 ml / g and a pore size of 207 m³ / g. 2 Specific surface area per g.

[0178] Example 6: Application of catalysts in selective hydrogenation

[0179] The activity of catalysts A, B, C, D, and E was evaluated by selective hydrogenation experiments using a mixture of model molecules in a 500 ml stirred autoclave reactor. Typically, 2–6 g of catalyst was sulfided at atmospheric pressure in a sulfidation bench with an H2S / H2 mixture containing 15 vol% H2S at a rate of 1 l / g·h of catalyst, maintained at 400 °C for 2 hours (temperature rise rate of 5 °C / min), followed by sulfidation at 200 °C under pure hydrogen for 2 hours. This procedure allows for sulfidation rates greater than 70% for all catalysts according to the invention. The thus sulfided catalyst was transferred to the reactor in the absence of air and then contacted with 250 ml of model feedstock at a total pressure of 1.5 MPa and a temperature of 160 °C. During the experiment, the pressure was kept constant by supplying hydrogen. The raw material used for the activity test has the following composition in n-heptane: 1000 wt ppm of sulfur in the form of thiophene in the form of 3-methylthiophene, 500 wt ppm of sulfur in the form of 2-propanethiol in the form of thiol, 10 wt% of olefin in the form of 1-hexene, and 1 wt% of diene in the form of isoprene.

[0180] The test time t=0 corresponds to the contact between the catalyst and the feedstock. The test duration was set to 200 minutes, and gas chromatography analysis of the obtained liquid effluent was used to evaluate the activity of various catalysts in the hydrogenation of isoprene (formation of methylbutene), the hydrogenation of 1-hexene (formation of n-hexane), and the molecular weight increase of 2-propanethiol (disappearance of 2-propanethiol).

[0181] The activity of the catalyst for each reaction is defined relative to the rate constant obtained for each reaction normalized to one gram of catalyst. The rate constant is calculated assuming the reaction order is 1. The activity of catalyst A is normalized to 100%.

[0182] The selectivity of a catalyst for the hydrogenation of isoprene is equal to the ratio of its activity in the hydrogenation of isoprene to its activity in the hydrogenation of 1-hexene: A(isoprene) / A(1-hexene). The selectivity of catalyst A is normalized to 100%.

[0183] The results obtained on various catalysts are reported in Table 1 below.

[0184] Table 1

[0185] catalyst A B C D E Diene hydrogenation activity 100 52 21 81 92 Thiols increase activity due to their molecular weight 100 63 13 94 90 Diene hydrogenation selectivity 100 102 87 90 64

[0186] Selective hydrogenation performance of catalysts A to E

[0187] Catalyst A according to the present invention has been found to have a systematically higher diene hydrogenation activity and thiol molecular weight increase activity than other catalysts. Furthermore, catalyst A according to the present invention consistently exhibits the highest selectivity.

Claims

1. A method for selectively hydrogenating gasoline containing polyunsaturated compounds and light sulfur compounds, wherein the hydrogenation is carried out at a temperature of 80°C-220°C for 1 hour. -1 -10h -1 A liquid hourly space velocity and a pressure of 0.5-5 MPa allow gasoline and hydrogen to contact the catalyst, and the molar ratio between hydrogen and the diene to be hydrogenated is greater than 1 and less than 100 mol / mol. The catalyst comprises at least one Group VIB metal, at least one Group VIII metal, and a mesoporous-macroporous alumina support with a bimodal mesoporous distribution, wherein: - The volume of the mesopores with a diameter greater than or equal to 2 nm and less than 18 nm is equivalent to 10%-30% of the total pore volume of the carrier. - The volume of the mesopores with a diameter greater than or equal to 18 nm and less than 50 nm is equivalent to 30%-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 is equivalent to 30%-50% of the total pore volume of the carrier.

2. The method of claim 1, wherein the carrier has a density of 50-210m. 2 Specific surface area per g.

3. The method of claim 1, wherein the carrier has a total pore volume of 0.7-1.3 ml / g.

4. The method according to any one of claims 1-3, wherein the volume of the mesopore having a diameter greater than or equal to 2 nm and less than 18 nm is equivalent to 15%-25% of the total pore volume of the carrier.

5. The method according to any one of claims 1-3, wherein the volume of the mesopore having a diameter greater than or equal to 18 nm and less than 50 nm is equivalent to 35%-45% of the total pore volume of the carrier.

6. The method of any one of claims 1-3, wherein the volume of the macropores having a diameter greater than or equal to 50 nm and less than 8000 nm is equivalent to 35%-50% of the total pore volume of the carrier.

7. The method according to any one of claims 1-3, wherein the content of a Group VIB metal in the catalyst, expressed in oxide form, is 1%-30% by weight relative to the total weight of the catalyst.

8. The method according to any one of claims 1-3, wherein the content of Group VIII metals in the catalyst, expressed in oxide form, is 1%-20% by weight relative to the total weight of the catalyst.

9. The method according to any one of claims 1-3, wherein the molar ratio of the group VIII metal to the group VIB metal is 0.3-3 mol / mol.

10. The method of claim 8, wherein the Group VIII metal is nickel.

11. The method of claim 7, wherein the Group VIB metal is molybdenum.

12. The method of any one of claims 1-3, wherein the pore distribution of the mesopores having a diameter greater than or equal to 2 nm and less than 18 nm is concentrated in the numerical range of 10.5-14.5 nm.

13. The method of any one of claims 1-3, wherein the pore distribution of the mesopores having a diameter greater than or equal to 18 nm and less than 50 nm is concentrated in the numerical range of 22-28 nm.

14. The method according to any one of claims 1-3, wherein the gasoline is catalytic cracked gasoline.

15. The method according to any one of claims 1-3, wherein the carrier is in the form of beads with a diameter of 2-4 mm.

16. The method of claim 15, wherein the carrier is obtained according to the following steps: s1) Dehydrate aluminum hydroxide or aluminum hydroxide at a temperature of 400℃-1200℃ for 0.1 seconds to 5 seconds to obtain aluminum oxide powder; s2) The alumina powder obtained in step s1) is formed into beads; s3) Heat-treat the alumina beads obtained in step s2) at a temperature of 200°C or higher; s4) The alumina beads obtained at the end of step s3) are subjected to hydrothermal treatment by immersion in water or aqueous solution and then staying in an autoclave at a temperature of 100℃-300℃. s5) Calcine the alumina beads obtained at the end of step s4) at a temperature of 500℃-820℃.

17. The method of claim 16, wherein step s1) comprises dehydrating aluminum hydroxide or aluminum hydroxide at a temperature of 600°C-900°C for 0.1 seconds to 4 seconds to obtain aluminum oxide powder.

18. The method of any one of claims 1-3, wherein the catalyst does not contain phosphorus.

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