Hydrodesulfurization process using a catalyst comprising a flash calcined alumina support

Abstract

The present invention relates to a process for hydrodesulfurization of a sulfur-containing olefinic gasoline fraction, wherein the gasoline fraction, hydrogen and a catalyst are contacted, the catalyst comprising an alumina support obtained by dehydrating aluminum hydroxide or aluminum oxyhydroxide at a temperature of 400°C to 1200°C for a time of 0.1 seconds to 5 seconds, at least one metal from Group VIB, at least one metal from Group VIII and phosphorus, the molar ratio of phosphorus to metal from Group VIB being 0.2 to 0.35.

Description

Technical Field

[0001] This invention relates to the field of hydrotreating gasoline fractions, particularly gasoline fractions produced by self-fluidized bed catalytic cracking units. More specifically, this invention relates to the use of catalysts in methods for hydrodesulfurizing sulfur-containing olefinic gasoline fractions (e.g., gasoline produced by autocatalytic cracking), for which the aim is to reduce the content of sulfur-containing compounds without hydrogenating olefins and aromatic compounds. Existing technology

[0002] Currently, both petroleum refining and petrochemicals are facing new restrictions. This is because all countries are gradually adopting strict sulfur specifications, aiming to achieve, for example, 10 ppm by weight sulfur in gasoline sold in Europe and Japan. The issue of reducing sulfur content is essentially focused on gasoline obtained through cracking, whether the cracking is catalytic cracking (FCC or fluid catalytic cracking) or non-catalytic cracking (coking, viscous cracking, steam cracking), which is a major precursor of sulfur in the gasoline pool.

[0003] One solution well known to those skilled in the art for reducing sulfur content involves hydrotreating (or hydrodesulfurizing) hydrocarbon fractions (particularly catalytic cracking gasoline) in the presence of hydrogen and a heterogeneous catalyst. However, this approach exhibits a major drawback: a very significant reduction in octane number, if the catalyst used lacks sufficient selectivity. This reduction in octane number is particularly related to the hydrotreating of olefins present in this type of gasoline (which occurs simultaneously with hydrodesulfurization). Therefore, unlike other hydrotreating methods, hydrodesulfurization of gasoline must be able to cope with a dual set of constraints: providing deep hydrodesulfurization of gasoline and limiting the hydrogenation of unsaturated compounds present.

[0004] One approach to addressing this dual problem is to use a hydrodesulfurization catalyst that is both active in hydrodesulfurization and highly selective for hydrodesulfurization relative to olefin hydrogenation.

[0005] For many years, it has been demonstrated that the addition of phosphorus to catalysts improves desulfurization activity (see, for example, US 3,287,280). This is typically done by adding phosphoric acid in the impregnation solution during catalyst preparation. Patent application US 2005 / 0261124 provides an addition ratio of 0.5 wt% to 10 wt% phosphorus relative to the catalyst weight, and US Patent 6,746,598 B1 provides a ratio of 0.1 wt% to 10 wt%. As described in patents US 4,880,525 and US 5,246,569, phosphorus has also been used as a dopant for the hydrodesulfurization activity of hydrocarbon feedstocks.

[0006] Patent EP 2 925 433 discloses catalysts in which the active phase based on CoMoP is deposited on a support obtained by kneading and extruding boehmite gel. These catalysts have a P / Mo molar ratio of 0.1–0.3. In this document, it has been demonstrated that this type of catalyst not only exhibits activity in hydrodesulfurization but also demonstrates improved hydrodesulfurization selectivity relative to olefin hydrogenation compared to CoMoP catalysts containing a support obtained from flash-calcined alumina (i.e., obtained through rapid dehydration of hydrargillite). The disclosed CoMoP catalyst supported on flash-calcined alumina has a P / Mo molar ratio of 0.15.

[0007] US Patent 7,981,828 discloses a catalyst in which the active phase based on CoMoP is deposited on a substrate with a specific surface area of ​​less than 135 m². 2 These catalysts are mounted on a support composed of / g alumina. The P / Mo molar ratio of these catalysts is 0.27-2.00, with higher technical performance observed in the range of 0.50-0.95. This preferred P / Mo molar ratio range can improve selectivity but decrease desulfurization activity.

[0008] Therefore, refiners still have a strong interest in hydrodesulfurization catalysts, especially for gasoline fractions, which have improved catalytic performance, particularly in terms of catalytic activity and / or selectivity in hydrodesulfurization. Thus, once such a catalyst is used, low-sulfur gasoline with no significant drop in octane number can be produced.

[0009] In this context, one object of the present invention is to provide a method for hydrodesulfurizing sulfur-containing olefinic gasoline fractions in the presence of a supported catalyst, wherein the method exhibits performance qualities in terms of activity and selectivity that are at least as good as, or even better than, methods known in the prior art.

[0010] Invention Theme

[0011] One subject of this invention is a method for hydrodesulfurizing a sulfur-containing olefinic gasoline fraction, wherein the gasoline fraction, hydrogen, and a catalyst are contacted, and the hydrodesulfurization method is carried out at a temperature of 200°C-400°C, a total pressure of 1-3 MPa, and for 1-10 hours. -1The time-space velocity (WHSV) and the hydrogen / gasoline fraction volume ratio (H / L) of 100-600 Sl / L are used, where WHSV is defined as the volumetric flow rate of the feedstock divided by the volume of the catalyst. The catalyst comprises an alumina support obtained by dehydrating aluminum hydroxide or aluminum oxyhydroxide at a temperature of 400°C-1200°C for 0.1-5 seconds, at least one metal from Group VIb, at least one metal from Group VIII, and phosphorus, wherein the molar ratio of phosphorus to the metal from Group VIb is 0.2-0.35.

[0012] The applicant company has unexpectedly discovered that using a catalyst supported on a support obtained by dehydration of aluminum hydroxide or alumina hydroxyaluminate, based on at least one metal from Group VIb, at least one metal from Group VIII, and phosphorus, with a specific molar ratio of Group VIb elements to phosphorus, in a hydrodesulfurization process can improve the catalytic performance quality of the process in terms of both catalytic activity and selectivity. Under the same operating conditions as those used in the prior art, this results in better feedstock conversion. This is because, without being constrained by any scientific theory, using a catalyst comprising an active phase with a well-defined composition of metals and phosphorus from Group VIb and Group VIII (with a specific molar ratio of Group VIb elements to phosphorus) can maximize the sulfidation of the active phase, thereby improving the activity of hydrodesulfurization; on the other hand, using a support prepared via a "flash calcination" route can optimize the interaction between the support surface and the active phase, thereby improving the selectivity of the catalyst.

[0013] According to one or more embodiments, the molar ratio of phosphorus to metals from Group VIb is 0.23-0.35.

[0014] According to one or more embodiments, the molar ratio of metals from Group VIII to metals from Group VIb in the catalyst is 0.1-0.8.

[0015] According to one or more embodiments, the content of Group VIb metals in oxide form of the catalyst is 1% to 30% by weight relative to the total weight of the catalyst.

[0016] According to one or more embodiments, the content of Group VIII metals in the catalyst, expressed in oxide form, is 0.3% to 10% by weight relative to the total weight of the catalyst.

[0017] According to one or more embodiments, the phosphorus content, expressed in P2O5 form, is 0.1% to 10% by weight relative to the total weight of the catalyst.

[0018] According to one or more embodiments, the Group VIII metal is cobalt.

[0019] According to one or more embodiments, the metal from Group VIb is molybdenum.

[0020] According to one or more embodiments, the alumina carrier is provided in the form of beads.

[0021] According to one or more embodiments, when the alumina support is in bead form, the alumina support is obtained by a preparation method including the following steps:

[0022] 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;

[0023] s2) The alumina powder obtained in step s1) is formed into beads;

[0024] s3) The beads obtained in step s2) are heat-treated at a temperature greater than or equal to 200°C, preferably 200°C-1200°C, more preferably 300°C-800°C, and still more preferably 300°C-750°C.

[0025] According to one or more embodiments, when the alumina support is in bead form, the alumina support is obtained by a preparation method that further includes the following steps:

[0026] s4) The material obtained at the end of step s3) is subjected to hydrothermal treatment by immersion in water or an aqueous solution and then staying in an autoclave at a temperature of 100℃-300℃;

[0027] s5) The material obtained at the end of step s4) is calcined at a temperature of 500℃-1100℃.

[0028] According to one or more embodiments, the alumina support in bead form exhibits a size of 50-420 m. 2 Specific surface area per g.

[0029] According to one or more embodiments, the alumina support in bead form exhibits a thickness of 50-210 m. 2 Specific surface area per g.

[0030] According to one or more embodiments, the alumina carrier is provided in the form of an extrudate.

[0031] According to one or more embodiments, the alumina support in extrusion form is obtained by a preparation method comprising the following steps:

[0032] 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 an aluminum oxide-based material;

[0033] s2′) Knead and extrude the alumina-based material obtained at the end of step s1′) to obtain an extruded material;

[0034] s3′) is heat-treated at a temperature greater than or equal to 200℃;

[0035] s4′) The material obtained at the end of step s3′) is subjected to hydrothermal treatment by impregnation with water or an aqueous solution, preferably an acidic aqueous solution, followed by residence in an autoclave at a temperature of 100°C-300°C, preferably 150°C-250°C;

[0036] The material obtained at the end of step s4′) is calcined at a temperature of 500℃-1100℃, preferably 550℃-800℃.

[0037] According to one or more embodiments, the extruded alumina support exhibits a thickness of 50-210 m. 2 Specific surface area per g.

[0038] According to one or more embodiments, the aluminum hydroxide or aluminum hydroxyaluminate is gibbsite.

[0039] According to one or more embodiments, the gasoline is gasoline that produces an autocatalytic cracking unit. Invention Details

[0041] 1. Definition

[0042] 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.

[0043] According to standard ASTM D4284-92, at a wetting angle of 140°, for example using MicromeritiCs TM Autopore III of the brand TM The equipment measures the total pore volume using the mercury intrusion porosimetry method.

[0044] 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).

[0045] The metal content from Group VIII, the metal content from Group VIb, and the phosphorus content were measured by X-ray fluorescence method.

[0046] 2. Description

[0047] Preparation of carrier

[0048] In the context of the method according to the invention, the alumina support for the catalyst is obtained by rapidly dehydrating a precursor of the type of aluminum hydroxide or aluminum hydroxide, preferably, for example, gibbsite produced by a process commonly known as the "Bayer" process. This method is described in particular detail in the literature *Alumina*, in *Handbook of Porous Solids*, edited by F. Schüth, K. SWSing, and J. Weitkamp, ​​Wiley-VCH, Weinheim, Germany, 2002, pp. 1591-1677. This method can produce alumina commonly referred to as "flash-burned alumina".

[0049] According to the first alternative form, the carrier used in the context of the method according to the invention is provided in the form of beads. The preparation of the carrier includes the following steps:

[0050] 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;

[0051] s2) The alumina powder obtained in step s1) is formed into beads;

[0052] s3) The beads obtained in step s2) are heat-treated at a temperature greater than or equal to 200°C, preferably 200°C-1200°C, more preferably 300°C-800°C, and still more preferably 300°C-750°C.

[0053] Advantageously, step s1) is carried out in the presence of a hot air stream, such as dry or humid air, so that evaporated water can be removed and entrained quickly.

[0054] Aluminum hydroxide can be selected from gibbsite or diaspore. Aluminum hydroxide can be selected from boehmite or diaspore.

[0055] Preferably, step s1) is performed using gibbsite.

[0056] Advantageously, step s1) can be performed at least twice before step s2).

[0057] Preferably, before forming according to step s2), the alumina powder obtained at the end of step s1) is ground to a particle size of 10-200 μm.

[0058] Typically, the alumina powder obtained at the end of step s1) is washed with water or an acidic aqueous solution. When the washing step is performed with an acidic aqueous solution, any inorganic or organic acid can be used. For inorganic acids, nitric acid or sulfuric acid is 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.

[0059] Step s2), which involves shaping the catalyst support into beads, is typically performed using a rotary technique, such as a rotary granulator or rotary drum. This type of method, well-known to those skilled in the art as granulation, yields beads with controlled diameter and pore distribution, dimensions and distributions typically formed during an agglomeration step. 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. Preferably, the alumina support is shaped into beads with a diameter preferably 0.8-10 mm, more preferably 1-5 mm. Preferably, step s2) is performed to obtain beads with a diameter of 500-1100 kg / m³. 3 Preferred weight: 700-950 kg / m³ 3 The original filling density of alumina beads.

[0060] According to an alternative secondary embodiment, during step s2) above, another method of forming the carrier includes mixing one or more compounds, referred to as pore-forming compounds, with the alumina powder obtained at the end of step s1) before or during the coalescence step. Once heated, these compounds dissipate, thereby forming pores in the beads. Pore-forming compounds used may include, for example, wood flour, charcoal, carbon black, sulfur, tar, plastics or plastic emulsions such as polyvinyl chloride, polyvinyl alcohol, naphthalene, etc. The amount of pore-forming compound added is determined by the desired volume.

[0061] According to step s3), the alumina powder to be formed into beads is heat-treated at a temperature greater than or equal to 200°C, preferably 200°C-1200°C, preferably 300°C-800°C, and most preferably 300°C-750°C, for a duration typically 1-24 hours, preferably 1-6 hours. At the end of step s3), the obtained alumina beads 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.

[0062] In an alternative embodiment of the invention, the alumina beads obtained at the end of step s3) are further subjected to a hydrothermal treatment in step s4) by impregnating the alumina beads with water or an aqueous solution, preferably an acidic aqueous solution, and then holding the alumina beads in an autoclave at a temperature of 100°C-300°C, preferably 150°C-250°C, to obtain aggregates. The hydrothermal treatment step s4) is typically carried out at a temperature of 100°C-300°C, preferably 150°C-250°C, for a duration of more than 45 minutes, preferably 1 hour to 24 hours, and very preferably 1.5 hours to 12 hours. The hydrothermal treatment is typically 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 solution with 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 compounds 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 anions having the general formula: R-COO (e.g., formate and acetate ions).

[0063] Subsequently, the agglomerate obtained at the end of step s4) is calcined in step s5) at a temperature of 500℃-1100℃, preferably 550℃-1050℃, for a duration typically 1-24 hours, preferably 1-6 hours. This calcination is usually performed to obtain a product with a particle size of 50-210 μm.2 / g, preferably 70-180m 2 / g, or even more preferably 70-160m 2 Alumina beads with a specific surface area of ​​ / g.

[0064] According to the second alternative, the carrier used in the context of the method according to the invention is provided in the form of an extrudate. According to this second alternative, the preparation of the carrier includes the following steps:

[0065] 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 an aluminum oxide-based material;

[0066] s2′) Knead and extrude the alumina-based material obtained at the end of step s1′) to obtain an extruded material;

[0067] s3′) is heat-treated at a temperature greater than or equal to 200℃;

[0068] s4′) The material obtained at the end of step s3′) is subjected to hydrothermal treatment by impregnation with water or an aqueous solution, preferably an acidic aqueous solution, followed by residence in an autoclave at a temperature of 100°C-300°C, preferably 150°C-250°C;

[0069] The material obtained at the end of step s4′) is calcined at a temperature of 500℃-1100℃, preferably 550℃-800℃.

[0070] Aluminum hydroxide can be selected from gibbsite, diaspore, or diaspore. Aluminum hydroxide can be selected from boehmite or diaspore.

[0071] Preferably, step s1′) is performed using gibbsite.

[0072] In step s2′), during the forming process of the alumina-based material, one or more pore-forming materials that disappear upon heating are typically added. The pore-forming materials are selected from wood flour, charcoal, sulfur, tar, plastic materials, emulsions of plastic materials, polyvinyl alcohol, and naphthalene.

[0073] In step s3′), the extruded material obtained at the end of step s2′ is heat-treated at a temperature greater than or equal to 200°C, preferably 200°C-1200°C, preferably 300°C-800°C, and more preferably 300°C-750°C, for a duration typically 1-24 hours, preferably 1-6 hours. At the end of step s3′), the obtained extruded material has a particle size of 50-420 μm. 2 / g, preferably 60-350m 2 / g, more preferably 80-300m 2 Specific surface area per g.

[0074] In step s4′), the hydrothermal treatment is typically carried out at a temperature of 100°C-300°C, preferably 150°C-250°C, for a duration of more than 45 minutes, preferably 1-24 hours, and very preferably 1.5-12 hours. The hydrothermal treatment is typically 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 compounds 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 anions having the general formula R-COO (e.g., formate and acetate ions).

[0075] In step s5′), the material obtained at the end of step s4′ is calcined at a temperature of 500°C-1100°C, preferably 550°C-1050°C, for a duration typically 1-24 hours, preferably 1-6 hours. This calcination is typically performed to obtain a specific surface area of ​​50-210 m². 2 / g, preferably 70-180m 2 / g, more preferably 70-160m 2 / g of extruded alumina.

[0076] Therefore, at the end of the method for preparing the carrier:

[0077] - When the carrier is provided in bead form and when the preparation method does not include the hydrothermal treatment step s4) and the calcination step s5), the specific surface area of ​​the carrier is 50-420 m². 2 / g, preferably 60-350m 2 / g, more preferably 80-300m 2 / g;

[0078] - When the carrier is provided in bead form and when the preparation method includes a hydrothermal treatment step s4) and a calcination step s5), the specific surface area of ​​the carrier is 50-210 m². 2 / g, preferably 70-180m 2 / g, more preferably 70-160m 2 / g;

[0079] - When the carrier is provided in extrusion form, the specific surface area of ​​the carrier is 50-210 m². 2 / g, preferably 70-180m 2 / g, more preferably 70-160m 2 / g.

[0080] The pore volume of the carrier is typically 0.4 cm³. 3 / g-1.3cm 3 / g, preferably 0.4cm 3 / g-1.1cm 3 / g.

[0081] catalyst

[0082] The catalyst used in the context of the hydrodesulfurization method according to the invention comprises an active phase consisting of at least one metal from Group VIb, at least one metal from Group VIII, and phosphorus.

[0083] The metals from Group VIb present in the active phase of the catalyst are preferably selected from molybdenum and tungsten, more preferably molybdenum. The metals from Group VIII present in the active phase of the catalyst are preferably selected from cobalt, nickel, and mixtures of the two elements, more preferably cobalt.

[0084] The total content of the group VIII metal relative to the total weight of the catalyst is typically 0.3 wt% to 10 wt% (expressed as oxides of the group VIII metal), preferably 0.4 wt% to 8 wt%, more preferably 0.45 wt% to 7 wt%, very preferably 0.5 wt% to 6 wt%, and still more preferably 0.5 wt% to 5 wt% 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.

[0085] The content of the Group VIb metal relative to the total weight of the catalyst is typically 1%-30% by weight (expressed as an oxide of the Group VIb metal), preferably 2%-20% by weight, more preferably 2%-15% by weight, and very preferably 3%-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.

[0086] The molar ratio of the catalyst from Group VIII metals to Group VIb metals is typically 0.1-0.8, preferably 0.2-0.6, more preferably 0.3-0.5, and still more preferably 0.35-0.45.

[0087] The phosphorus content of P2O5 is typically 0.1% to 10% by weight relative to the total weight of the catalyst, preferably 0.3% to 5% by weight relative to the total weight of the catalyst, and even more preferably 0.4% to 3% by weight relative to the total weight of the catalyst.

[0088] The molar ratio of phosphorus to metals from Group VIb is 0.2-0.35, preferably 0.23-0.35, and more preferably 0.25-0.35.

[0089] When the support is provided in bead form and when the preparation method does not include the hydrothermal treatment step s4) and the calcination step s5), the specific surface area of ​​the catalyst is 40-350 m². 2 / g, preferably 50-330m 2 / g, more preferably 70-300m 2 / g.

[0090] When the support is provided in bead form and when the preparation method includes a hydrothermal treatment step (s4) and a calcination step (s5), the specific surface area of ​​the catalyst is 60-170 m². 2 / g, more preferably 60-150m 2 / g.

[0091] When the support is provided in extrusion form, the catalyst has a specific surface area of ​​60-170 m². 2 / g, more preferably 60-150m 2 / g.

[0092] Catalyst preparation

[0093] The active phase can be introduced onto the support using any preparation method known to those skilled in the art. Adding the active phase to the support includes contacting at least one Group VIb metal component, at least one Group VIII metal component, and phosphorus with the support to obtain a catalyst precursor.

[0094] According to the first embodiment, the Group VIb metal component, the Group VIII metal component, and the phosphorus component are deposited on the support through one or more co-impregnation stages, that is, the Group VIb metal component, the Group VIII metal component, and the phosphorus component are simultaneously introduced into the support. The one or more co-impregnation steps are preferably carried out by dry impregnation or excessive impregnation with a solution. When the first embodiment includes several co-impregnation steps, each co-impregnation step is preferably followed by an intermediate drying step, typically at a temperature below 200°C, advantageously 50-180°C, preferably 60-150°C, and most preferably 75-140°C, for 0.5-24 hours, preferably 0.5-12 hours.

[0095] According to a preferred embodiment of co-impregnation, the impregnation solution is preferably an aqueous solution. Preferably, when the aqueous impregnation solution contains cobalt, molybdenum, and phosphorus, the aqueous impregnation solution is prepared under pH conditions that promote the formation of heteropolyanions in the solution. For example, such an aqueous solution has a pH of 1-5.

[0096] According to a second embodiment, a catalyst precursor is prepared by sequentially depositing a Group VIb metal component, a Group VIII metal component, and phosphorus on the support in any order. The deposition can be carried out using methods well known to those skilled in the art, such as dry impregnation, over-impregnation, or deposition-precipitation. In this second embodiment, the deposition of the Group VIb metal component, the Group VIII metal component, and phosphorus can be carried out through several impregnations, with an intermediate drying step between two consecutive impregnations, typically at a temperature below 200°C, advantageously 50-180°C, preferably 60-150°C, and most preferably 75-140°C, for 0.5-24 hours, preferably 0.5-12 hours.

[0097] Regardless of the deposition method used for metals and phosphorus, the solvent selected to participate in the composition of the impregnation solution is to dissolve the metal precursor of the active phase, such as water or an organic solvent (e.g., alcohol).

[0098] For example, sources of molybdenum can include oxides and hydroxides, molybdic acid and its salts, especially ammonium salts, such as ammonium molybdate or ammonium heptamolybdate, phosphomolybdic acid (H3PMo). 12 O 40 ) and its salts, and optionally silicomolybdic acid (H4SiMo) 12 O 40 Molybdenum can also be derived from any heteropoly compound, such as Keggin type, vacant Keggin type, substituted Keggin type, Dawson type, Anderson type, or Strandberg type. Preferably, molybdenum trioxide and Keggin type, vacant Keggin type, substituted Keggin type, and Strandberg type heteropoly compounds are used.

[0099] The tungsten precursors that can be used are well known to those skilled in the art. For example, among the sources of tungsten, oxides and hydroxides, tungstic acid and its salts, especially ammonium salts such as ammonium tungstate or ammonium metatungstate, phosphotungstic acid and its salts, and optionally silicotungstic acid (H4SiW) can be used. 12 O 40 ) and its salts. The source of tungsten can also be any heteropoly compound, such as Keggin type, absent Keggin type, substituted Keggin type, or Dawson type. Oxides and ammonium salts, such as ammonium metatungstate, or Keggin type, absent Keggin type, or substituted Keggin type heteropoly anions, are preferred.

[0100] The cobalt precursors that can be used are advantageously selected from, for example, oxides, hydroxides, basic carbonates, carbonates, and nitrates. Cobalt hydroxide and cobalt carbonate are preferred.

[0101] The nickel precursors that can be used are advantageously selected from, for example, oxides, hydroxides, basic carbonates, carbonates, and nitrates. Nickel hydroxide and basic nickel carbonate are preferred.

[0102] Phosphorus can be advantageously introduced into the catalyst in various ways during the various steps of catalyst preparation. Phosphorus can be introduced during the forming of the alumina support, or preferably after forming. Phosphorus can be advantageously introduced alone or as a mixture with at least one of Group VIb and Group VIII metals. Phosphorus is preferably introduced as a mixture with Group VIb and Group VIII metal precursors, by dry impregnation of the alumina support with a solution containing the metal precursor and the phosphorus precursor, either completely or partially, onto the formed alumina support. A preferred source of phosphorus is orthophosphoric acid (H3PO4), but its salts (e.g., ammonium phosphate) and esters or mixtures thereof are also suitable. Phosphorus can also be introduced simultaneously with one or more Group VIb elements in the form of, for example, Keggin-type, absent Keggin-type, substituted Keggin-type, or Strandberg-type heteropolyanions.

[0103] At the end of one or more steps involving contacting the Group VIb, Group VIII metals, and phosphorus with the support, the catalyst precursor is subjected to a drying step using any technique known to those skilled in the art. This is advantageously carried out under atmospheric or reduced pressure. Preferably, this step is carried out under atmospheric pressure. The step is carried out at a temperature below 200°C, preferably 50°C-180°C, preferably 60°C-150°C, and most preferably 75°C-140°C.

[0104] 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.

[0105] Preferably, the drying step lasts for 30 minutes to 24 hours, more preferably 1 hour to 12 hours.

[0106] At the end of the drying step, a dried catalyst is obtained, which can be used as a hydrotreating catalyst after the activation stage (sulfidation step).

[0107] According to an alternative form, the dried catalyst can be subjected to a subsequent calcination step, for example, in air at a temperature greater than or equal to 200°C. Calcination is typically carried out at a temperature less than or equal to 600°C, preferably 200°C-600°C, and particularly preferably 250°C-500°C. The calcination time is typically 0.5 hours to 16 hours, preferably 1 hour to 6 hours. It is usually carried out in air. Calcination can convert Group VIb and Group VIII metal precursors into oxides.

[0108] 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).

[0109] Method of hydrogenating desulfurization of gasoline

[0110] The hydrotreating method involves contacting a sulfur-containing olefin gasoline fraction with the above-mentioned catalyst and hydrogen under the following conditions:

[0111] Temperature range: -200-400℃, preferably 230-330℃;

[0112] -1-3MPa, preferably 1.5-2.5MPa total pressure;

[0113] -1-10h -1 , preferably 2-6h -1 The definition of is the volumetric flow rate of the feedstock divided by the volumetric space velocity (HSV) of the catalyst.

[0114] A hydrogen / gasoline feedstock volume ratio of -100-600Sl / l, preferably 200-400Sl / l.

[0115] Therefore, the method according to the invention can process any type of sulfur-containing olefinic gasoline fraction, for example, fractions from self-coking, viscosity-reducing cracking, steam cracking, or catalytic cracking (FCC, fluidized bed catalytic cracking) units. Such gasoline may optionally contain a substantial portion derived from other production methods, such as atmospheric distillation (gasoline produced by straight distillation or straight-run gasoline) or self-conversion methods (coking or steam cracking gasoline). The feedstock preferably consists of gasoline fractions from self-catalytic cracking units.

[0116] The raw material is advantageously a gasoline fraction containing sulfur compounds and olefins, with a boiling point of 30°C to less than 250°C, preferably 35°C-240°C, and more preferably 40°C-220°C.

[0117] The sulfur content of gasoline fractions produced by catalytic cracking (FCC) depends on the sulfur content of the feedstock processed by FCC, whether the FCC feedstock was pretreated, and the fraction's final boiling point. Typically, the overall sulfur content of gasoline fractions, especially those produced by FCC, is greater than 100 ppm by weight, and in most cases greater than 500 ppm by weight. For gasoline with a final boiling point greater than 200°C, the sulfur content is usually greater than 1000 ppm by weight; in some cases, it can even reach values ​​in the range of 4000-5000 ppm by weight.

[0118] In addition, gasoline produced by the self-catalytic cracking (FCC) unit contains, on average, 0.5 wt% to 5 wt% dienes, 20 wt% to 50 wt% olefins, and 10 wt% to 0.5 wt% sulfur, including typically less than 300 ppm thiols. Thiols are generally concentrated in the lighter fractions of gasoline, more specifically, in fractions with boiling points below 120°C.

[0119] It should be noted that sulfur-containing compounds present in gasoline can also include heterocyclic sulfur-containing compounds, such as thiophene, alkylthiophene, or benzothiophene. Unlike thiols, these heterocyclic compounds cannot be removed by extraction. Therefore, these sulfur-containing compounds are removed by hydrogenation, which results in their conversion into hydrocarbons and H2S.

[0120] Preferably, the gasoline processed by the method according to the invention is heavy gasoline (or heavy cracked naphtha, HCN) produced from a distillation step aimed at separating a wide-range cracked naphtha (or full-range cracked naphtha, FRCN) of gasoline produced by a cracking process into light gasoline (light cracked naphtha, LCN) and heavy gasoline HCN. The fractionation points of the light and heavy gasoline are determined to limit the sulfur content of the light gasoline and make it usable in a gasoline pool, preferably without requiring additional post-treatment. Advantageously, a selective hydrogenation step is performed on the wide-range FRCN prior to the distillation step. Example

[0121] Example 1: Catalyst A (according to the present invention)

[0122] The support S1 for catalyst A, provided in bead form, is rapidly calcined from gibbsite ( Merck TM The activated alumina powder is obtained by dehydrating the material. A hot gas flow allows for very rapid removal and entrainment of evaporated water. The temperature is set to 800°C, and the contact time between the material to be dehydrated and the gas is 1 second. The obtained activated alumina powder is ground to a particle size of 10-200 μm and then washed with water. Subsequently, the alumina powder is granulated into beads using a granulator. Carbon black (N990) is adjusted... The amount of ) was used to obtain an original fill density of 785 kg / m³. 3 The beads, after sieving, have a diameter of 2-4 mm. After heat treatment at 720℃ for 2 hours, the specific surface area of ​​the beads is 200 m². 2 / g. Subsequently, the beads were subjected to hydrothermal treatment by impregnation with an acidic aqueous solution. This hydrothermal treatment was carried out at 200°C in a rotary basket autoclave for 6.5 hours, and the impregnation solution was an acidic aqueous solution containing aluminum nitrate (0.1N, Merck). TMThe obtained agglomerates were then calcined at 650°C for 2 hours. This yielded alumina support S1 in bead form, with a particle size of 146 μm. 2 Specific surface area per g and 0.99 cm² 3 / g total pore volume.

[0123] The water absorption volume of carrier S1 is 0.95 ml / g. This was achieved by using 1.15 g of molybdenum oxide (MoO3 > 99.5%, Merck)... TM 0.30g of cobalt hydroxide (95% Co(OH)2, Merck) TM ) and 0.26g of phosphoric acid (85% H3PO4, Merck) TM An impregnation solution was prepared by heating a solution in 9.3 ml of distilled water at 90 °C for 3 hours. After dry impregnation of 10 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, relative to the total weight of the catalyst, contained 2.0 wt% CoO, 10 wt% MoO3, and 1.4 wt% P2O5, i.e., a Co / Mo atomic ratio of 0.38 and a P / Mo atomic ratio of 0.28. The total pore volume of catalyst A was 0.84 ml / g, and the specific surface area was 118 m². 2 / g. The metal content, measured in its oxide form, is shown in Table 1 below.

[0124] Example 2: Catalyst B (according to the present invention)

[0125] The support S2 for catalyst B, provided in bead form, is rapidly calcined from gibbsite ( Merck TM The activated alumina powder is obtained by dehydrating the material. A hot gas flow allows for very rapid removal and entrainment of evaporated water. The temperature is set to 800°C, and the contact time between the material to be dehydrated and the gas is 1 second. The obtained activated alumina powder is ground to a particle size of 10-200 μm and then washed with water. Subsequently, the alumina powder is granulated into beads using a granulator. The initial packed density of the beads is 785 kg / m³. 3 The diameter of the sieved alumina carrier is 2-4 mm. After heat treatment at 720℃ for 2 hours, alumina carrier S2 in bead form is obtained, with a specific surface area of ​​200 m². 2 / g and the total pore volume is 0.75cm³. 3 / g.

[0126] The water absorption volume of carrier S2 is 0.73 ml / g. This was achieved by using 1.15 g of molybdenum oxide (MoO3 > 99.5%, Merck)... TM0.30g of cobalt hydroxide (95% Co(OH)2, Merck) TM ) and 0.26g of phosphoric acid (85% H3PO4, Merck) TM An impregnation solution was prepared by heating a solution in 7.1 ml of distilled water at 90 °C for 3 hours. After dry impregnation of 10 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 B, relative to the total weight of the catalyst, contained 2.0 wt% CoO, 10 wt% MoO3, and 1.4 wt% P2O5, i.e., a Co / Mo atomic ratio of 0.38 and a P / Mo atomic ratio of 0.28. The total pore volume of catalyst B was 0.65 ml / g, and the specific surface area was 118 m². 2 / g. The metal content, measured in its oxide form, is shown in Table 1 below.

[0127] Example 3: Catalyst C (not according to the invention)

[0128] In this embodiment not according to the invention, the P / Mo ratio is less than 0.2.

[0129] Catalyst C was prepared on support S1 according to Example 1. This was achieved by using 1.15 g of molybdenum oxide (MoO3 > 99.5%, Merck)... TM 0.30g of cobalt hydroxide (95% Co(OH)2, Merck) TM ) and 0.14g of phosphoric acid (85% H3PO4, Merck) TM An impregnation solution was prepared by heating a solution in 9.3 ml of distilled water at 90 °C for 3 hours. After dry impregnation of 10 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 C contained 2.0 wt% CoO, 10 wt% MoO3, and 0.75 wt% P2O5, i.e., a Co / Mo atomic ratio of 0.38 and a P / Mo atomic ratio of 0.15. The total pore volume of catalyst C was 0.85 ml / g, and the specific surface area was 120 m². 2 / g. The metal content, measured in its oxide form, is shown in Table 1 below.

[0130] Example 4: Catalyst D (not according to the invention)

[0131] In this embodiment not according to the invention, the P / Mo ratio is greater than 0.35.

[0132] Catalyst D was prepared on support S1 according to Example 1. This was achieved by using 1.15 g of molybdenum oxide (MoO3 > 99.5%, Merck)... TM 0.30g of cobalt hydroxide (95% Co(OH)2, Merck) TM ) and 0.48g of phosphoric acid (85% H3PO4, Merck) TM An impregnation solution was prepared by heating a solution in 9.3 ml of distilled water at 90 °C for 3 hours. After dry impregnation of 10 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 D contained 2.0 wt% CoO, 10 wt% MoO3, and 2.55 wt% P2O5, i.e., a Co / Mo atomic ratio of 0.38 and a P / Mo atomic ratio of 0.52. The total pore volume of catalyst D was 0.82 ml / g, and the specific surface area was 117 m². 2 / g. The metal content, measured in its oxide form, is shown in Table 1 below.

[0133] Example 5: Catalyst E (not according to the invention)

[0134] In this embodiment not according to the invention, the alumina support is not obtained by dehydration of aluminum hydroxide or aluminum hydroxide.

[0135] The carrier S4, provided in extrusion form, is fed through an MX-type double Z-arm kneader. kneading boehmite powder in a closed container Obtain the following: Add a binder (nitric acid, HNO3) up to 4 g / 100 g boehmite. Water is also gradually introduced to achieve a loss on ignition of approximately 50%, adjusting this value to obtain a homogeneous and cohesive slurry. The slurry is then extruded through a die with a diameter of 1.8 mm using a piston extruder. The resulting extrudate is dried at 120°C for 12 hours and then calcined at 900°C for 2 hours. The obtained extrudate has a thickness of 140 m... 2 Specific surface area per g and 0.73 cm² 3 / g total pore volume.

[0136] The water absorption volume of carrier S4 is 0.72 ml / g. This was achieved by using 1.15 g of molybdenum oxide (MoO3 > 99.5%, Merck)... TM 0.30g of cobalt hydroxide (95% Co(OH)2, Merck) TM ) and 0.26g of phosphoric acid (85% H3PO4, Merck) TMAn impregnation solution was prepared by heating a solution in 7.0 ml of distilled water at 90 °C for 3 hours. After dry impregnation of 10 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 E contained 2.0 wt% CoO, 10 wt% MoO3, and 1.4 wt% P2O5, i.e., a Co / Mo atomic ratio of 0.38 and a P / Mo atomic ratio of 0.28. The total pore volume of catalyst E was 0.63 ml / g, and the specific surface area was 118 m². 2 / g. The metal content, measured in its oxide form, is shown in Table 1 below.

[0137] Table 1

[0138]

[0139] Characteristics of catalysts A, B, C, D, and E

[0140] Example 6: Evaluation of the performance quality of the catalyst used in the hydrodesulfurization reactor

[0141] The catalytic performance of various catalysts was evaluated using a model feedstock representing catalytic cracking gasoline, containing 10 wt% 2,3-dimethylbut-2-ene and 0.33 wt% 3-methylthiophene (i.e., the feedstock contains 1000 wt% sulfur). Heptane was used as the solvent.

[0142] Hydrodesulfurization (HDS) was carried out in a fixed crossflow reactor in the presence of 4 ml of catalyst, at a total pressure of 1.5 MPa and a temperature of 210 °C, with a flow rate of HSV = 6 h. -1 (HSV = feed volume flow rate / catalyst volume) and an H2 / feed volume ratio of 300 Sl / l were used. Before the HDS reaction, the catalyst was in-situ sulfided for 2 hours at 350°C, atmospheric pressure, and a hydrogen stream containing 15 mol% H2S.

[0143] Each catalyst was placed sequentially in the reactor. Samples were taken at different time intervals and analyzed by gas chromatography to observe the disappearance of reactants and the formation of products.

[0144] The catalytic performance of the catalysts was evaluated in terms of catalytic activity and selectivity. Hydrodesulfurization (HDS) activity was represented by the rate constant (kHDS) of the HDS reaction of 3-methylthiophene, normalized by the introduced catalyst volume, and assumed first-order kinetics with respect to sulfur-containing compounds. Olefin hydrogenation (HydO) activity was represented by the rate constant of the hydrogenation reaction of 2,3-dimethylbut-2-ene, normalized by the introduced catalyst volume, and assumed first-order kinetics with respect to olefins.

[0145] The selectivity of the catalyst is represented by the normalized ratio of the rate constant, kHDS / kHydO. The kHDS / kHydO ratio increases with increasing catalyst selectivity. The obtained values ​​are normalized with reference to catalyst A (relative HDS activity and relative selectivity equal to 100). Therefore, the performance quality is relative to both HDS activity and relative selectivity.

[0146] Table 2

[0147] Relative HDS activity 100 119 87 71 105 Relative selectivity 100 98 92 108 75

[0148] The combined improvement in the activity and selectivity of the catalyst according to the invention is particularly advantageous in the case of hydrodesulfurization methods for gasoline containing olefins, for which the aim is to limit as much as possible the loss of octane number as possible due to the hydrogenation of olefins.

Claims

1. A method for hydrodesulfurizing a sulfur-containing olefinic gasoline fraction, wherein the gasoline fraction, hydrogen, and a catalyst are contacted, and the hydrodesulfurization method is carried out at a temperature of 200°C-400°C, a total pressure of 1-3 MPa, and for 1-10 hours. -1 The time-space velocity (WHSV) and the hydrogen / gasoline fraction volume ratio of 100-600 Sl / l are used, wherein the WHSV is defined as the volumetric flow rate of the feedstock / volume of the catalyst, and the catalyst comprises an alumina support obtained by dehydrating aluminum hydroxide or aluminum hydroxide at a temperature of 400°C-1200°C for 0.1-5 seconds, at least one metal from Group VIb, at least one metal from Group VIII, and phosphorus, wherein the molar ratio of phosphorus to the metal from Group VIb is 0.2-0.

28.

2. The method of claim 1, wherein the molar ratio of phosphorus to a metal from Group VIb is 0.23-0.

28.

3. The method of claim 1 or claim 2, wherein the molar ratio of the metal from group VIII to the metal from group VIb in the catalyst is 0.1-0.

8.

4. The method of claim 1 or claim 2, wherein the content of group VIb metals in oxide form of the catalyst is 1% to 30% by weight relative to the total weight of the catalyst.

5. The method of claim 1 or claim 2, wherein the content of group VIII metals in oxide form of the catalyst is 0.3% to 10% by weight relative to the total weight of the catalyst.

6. The method of claim 1 or claim 2, wherein the phosphorus content, expressed in P2O5 form, is 0.1% to 10% by weight relative to the total weight of the catalyst.

7. The method of claim 1 or claim 2, wherein the metal from Group VIII is cobalt.

8. The method of claim 1 or claim 2, wherein the metal from Group VIb is molybdenum.

9. The method of claim 1 or claim 2, wherein the alumina carrier is provided in the form of beads.

10. The method of claim 9, wherein the alumina support in bead form is obtained by a preparation method comprising 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) The beads obtained in step s2) are heat-treated at a temperature of 200℃-1200℃.

11. The method of claim 9, wherein the alumina support in bead form is obtained by a preparation method comprising the following steps: s1) Dehydrate aluminum hydroxide or aluminum hydroxide at a temperature of 600℃-900℃ for 0.1 seconds to 4 seconds to obtain aluminum oxide powder; s2) The alumina powder obtained in step s1) is formed into beads; s3) The beads obtained in step s2) are heat-treated at a temperature of 300℃-750℃.

12. The method of claim 10 or claim 11, wherein the alumina support in bead form is obtained by a preparation method further comprising the following steps: s4) The material obtained at the end of step s3) is subjected to hydrothermal treatment by immersion in water or an aqueous solution and then staying in an autoclave at a temperature of 100℃-300℃; s5) The material obtained at the end of step s4) is calcined at a temperature of 500℃-1100℃.

13. The method of claim 10 or claim 11, wherein the alumina support in bead form exhibits a thickness of 50-420 μm. 2 Specific surface area per g.

14. The method of claim 12, wherein the alumina support in bead form exhibits a thickness of 50-210 μm. 2 Specific surface area per g.

15. The method of claim 1 or claim 2, wherein the alumina carrier is provided in the form of an extrudate.

16. The method of claim 15, wherein the alumina support in extrusion form is obtained by a preparation method comprising the steps of: s1') Dehydrate aluminum hydroxide or aluminum hydroxide at a temperature of 400℃-1200℃ for 0.1 seconds to 5 seconds to obtain an aluminum oxide-based material; s2') Knead and extrude the alumina-based material obtained at the end of step s1') to obtain an extruded material; s3') is heat-treated at a temperature greater than or equal to 200℃; s4') The material obtained at the end of step s3') is subjected to hydrothermal treatment by immersion in water or an aqueous solution and then staying in an autoclave at a temperature of 100°C-300°C; The material obtained at the end of step s4') is calcined at a temperature of 500℃-1100℃.

17. The method of claim 15, wherein the alumina support in extrusion form is obtained by a preparation method comprising the steps of: s1') Dehydrate aluminum hydroxide or aluminum hydroxide at a temperature of 600℃-900℃ for 0.1 seconds to 4 seconds to obtain an aluminum oxide-based material; s2') Knead and extrude the alumina-based material obtained at the end of step s1') to obtain an extruded material; s3') is heat-treated at a temperature greater than or equal to 200℃; s4') The material obtained at the end of step s3') is subjected to hydrothermal treatment by immersion in an acidic aqueous solution and then residence in an autoclave at a temperature of 150°C-250°C; The material obtained at the end of step s4') is calcined at a temperature of 550℃-800℃.

18. The method of claim 16 or claim 17, wherein the alumina support in extruded form exhibits a thickness of 50-210 m. 2 Specific surface area per g.

19. The method of claim 1 or claim 2, wherein the aluminum hydroxide or aluminum hydroxide is gibbsite.

20. The method of claim 1 or claim 2, wherein the gasoline is gasoline that produces an autocatalytic cracking unit.

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