Hydrodesulfurization method using a catalyst containing flash alumina support

Abstract

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

Description

[Technical Field]

[0001] The present invention relates to the field of hydrogenation treatment of gasoline fractions, particularly gasoline fractions obtained from fluidized bed catalytic cracking units. More specifically, the present invention relates to the use of catalysts in the process of hydrodesulfurization of sulfur-containing olefinic gasoline fractions, such as gasoline obtained from catalytic cracking, where it is required to reduce the content of sulfur-containing compounds without hydrogenating olefins and aromatic compounds. [Background technology]

[0002] Petroleum refining and petrochemicals are now facing new constraints, as countries are gradually adopting stricter sulfur standards, the goal of which, for example in Europe and Japan, is to reduce the sulfur content in commercially available gasoline to 10 ppm by weight. The issue of reducing sulfur content is essentially focused on gasoline obtained by either catalytic cracking (FCC or fluid catalytic cracking) or non-catalytic cracking (coking, vis-breaking, steam cracking), which are the main precursors of sulfur in the gasoline pool.

[0003] A well-known solution to reduce sulfur content, as described by those skilled in the art, involves hydrotreating (or hydrodesulfurizing) hydrocarbon fractions (particularly catalytic cracking gasoline) in the presence of hydrogen and a heterogeneous catalyst. However, this process has a major drawback: if the catalyst used is not sufficiently selective, it causes a very significant decrease in octane number. This octane reduction is particularly related to the hydrogenation of olefins present in this type of gasoline, which occurs simultaneously with hydrodesulfurization. Therefore, unlike other hydrotreating processes, hydrodesulfurization of gasoline must be designed to address the dual antagonistic constraints of extreme hydrodesulfurization of gasoline and the limitation of hydrogenation of present unsaturated compounds.

[0004] One way to address these two problems is to use a hydrodesulfurization catalyst that is active in hydrodesulfurization and is also highly selective in hydrodesulfurization for the reaction of hydrogenating olefins.

[0005] It has been demonstrated for many years that adding phosphorus to a catalyst improves its desulfurization activity (see, for example, Patent Document 1). This is generally done by adding phosphoric acid to the impregnation solution during catalyst preparation. Patent Document 2 specifies the addition of phosphorus in a range of 0.5% to 10% by weight relative to the weight of the catalyst, and Patent Document 3 specifies a range of 0.1% to 10% by weight. Phosphorus is also used as a dopant for activity in the hydrodesulfurization of hydrocarbon feedstocks, as shown in Patent Documents 4 and 5.

[0006] Patent Document 6 discloses a catalyst in which a CoMoP-based active phase is deposited on a support obtained from a kneaded and extruded boehmite gel. The P / Mo molar ratio of these catalysts is between 0.1 and 0.3. This document demonstrates that this type of catalyst exhibits improved activity and selectivity in hydrodesulfurization of olefins compared to CoMoP catalysts including supports obtained from flash alumina, i.e., supports obtained by rapid dehydration of hydrargillite. The disclosed CoMoP catalyst on a flash alumina support has a P / Mo molar ratio of 0.15.

[0007] Patent Document 7 describes an active phase based on CoMoP, with a 135m 2 Catalysts deposited on a support made of alumina having a specific surface area of ​​less than 1 / g are disclosed. The P / Mo molar ratio of these catalysts is between 0.27 and 2.00, and for a more enhanced technical effect, it is in the range of 0.50 to 0.95. This preferred range of P / Mo molar ratio allows for improved selectivity despite a decrease in desulfurization activity.

[0008] Therefore, there is still a strong interest today among refiners in hydrodesulfurization catalysts that exhibit improved catalyst performance quality, particularly from the perspective of catalyst activity and / or selectivity in hydrodesulfurization, and thus enable the production of gasoline with a low sulfur content without significantly reducing the octane number once used, especially hydrodesulfurization catalysts for the hydrodesulfurization of gasoline fractions.

Prior Art Documents

Patent Documents

[0009]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Patent Document 6

Patent Document 7

Summary of the Invention

Problems to be Solved by the Invention

[0010] In this regard, one object of the present invention is to provide a method for the hydrodesulfurization of sulfur-containing olefinic gasoline fractions in the presence of a supported catalyst that exhibits performance quality in terms of activity and selectivity that is at least as good as, and in fact better than, that of known processes of the prior art.

Means for Solving the Problems

[0011] The subject of the present invention is a method for hydrodesulfurizing a sulfur-containing olefin-based gasoline fraction by contacting the sulfur-containing olefin-based gasoline fraction, hydrogen, and a catalyst, wherein the hydrodesulfurizing method is performed at a temperature between °C and 400 °C, a total pressure between 1 and 3 MPa, and a space velocity per hour defined as the flow rate of the raw material volume relative to the catalyst volume between 1 and 10 h⁻¹. -1 The method is carried out between 0.1 and 0.5, and the volume ratio of the hydrogen / gasoline fraction is between 100 and 600 Sl / l, wherein the catalyst comprises an alumina support obtained by dehydrating aluminum hydroxide or aluminum oxyhydroxide for a time between 0.1 and 5 seconds at a temperature between 400 and 1200°C, 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 between 0.2 and 0.35.

[0012] The applicant company has surprisingly discovered that using a catalyst based on at least one metal from Group VIb, at least one metal from Group VIII, and phosphorus, having a specific molar ratio of elements from Group VIb to phosphorus, in a hydrodesulfurization process on a support obtained by dehydrating aluminum hydroxide or aluminum oxyhydroxide, makes it possible to improve the catalytic performance quality of the method in terms of catalytic activity and selectivity. This results in a better conversion rate of the raw materials under the same operating conditions as those used in the prior art. This is because, without adhering to any one scientific theory, the use of a catalyst containing an active phase with a clearly defined composition of metals from Group VIb and VIII and phosphorus (having a specific molar ratio of elements from Group VIb to phosphorus) makes it possible to maximize the sulfidation of the active phase, thereby promoting activity in hydrodesulfurization, while the use of a support prepared by the "flash" pathway makes it possible to optimize the interaction between the surface of the support 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 between 0.23 and 0.35.

[0014] According to one or more embodiments, the molar ratio of the metal from Group VIII to the metal from Group VIb of the catalyst is between 0.1 and 0.8.

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

[0016] According to one or more embodiments, the content of the metal from Group VIII of the catalyst, expressed in the form of an oxide, is between 0.3% by weight and 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 between 0.1% by weight and 10% by weight relative to the total weight of the catalyst.

[0018] According to one or more embodiments, the metal from Group VIII 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 carrier is in the form of beads, the alumina carrier is obtained by a preparation method comprising the following steps: s1) A step to obtain alumina powder, in which aluminum hydroxide or aluminum oxyhydroxide is dehydrated at a temperature between 400°C and 1200°C, preferably between 600°C and 900°C, for a time between 0.1 seconds and 5 seconds, preferably between 0.1 seconds and 4 seconds. s2) A step of forming the alumina powder obtained in step s1) into the form of beads, s3) A step of heat-treating the beads obtained in step s2) at a temperature of 200°C or higher, preferably between 200°C and 1200°C, more preferably between 300°C and 800°C, and even more preferably between 300°C and 750°C.

[0022] According to one or more embodiments, when the alumina carrier is in the form of beads, the alumina carrier is obtained by a preparation process that further includes the following steps: s4) A step of hydrothermal treatment in which the material obtained at the end of step s3) is impregnated with water or an aqueous solution and then left in an autoclave at a temperature between 100°C and 300°C. s5) A process of firing the material obtained at the end of process s4) at a temperature between 500°C and 1100°C.

[0023] According to one or more embodiments, the alumina carrier in the form of beads is 50 to 420 m 2 This indicates the specific surface area between / g.

[0024] According to one or more embodiments, the alumina carrier in the form of beads is 50 to 210 m 2 This indicates the specific surface area between / g.

[0025] According to one or more embodiments, the alumina carrier is provided in the form of an extruded product.

[0026] According to one or more embodiments, an alumina carrier in the form of an extruded product is obtained by a preparation method comprising the following steps: s1') A step to obtain an alumina-based material, dehydrating aluminum hydroxide or aluminum oxyhydroxide for a time of 0.1 to 5 seconds, preferably 0.1 to 4 seconds, at a temperature between 400°C and 1200°C, preferably between 600°C and 900°C. s2') A process of mixing and extruding the alumina-based material obtained at the end of step s1') in order to obtain an extruded material, s3') A process of heat treatment at a temperature of 200℃ or higher. s4') The material obtained at the end of step s3') is impregnated with water or an aqueous solution, preferably an acidic aqueous solution, and then subjected to hydrothermal treatment by being kept in an autoclave at a temperature between 100°C and 300°C, preferably between 150°C and 250°C. s5') A step in which the material obtained at the end of step s4') is fired at a temperature between 500°C and 1100°C, preferably between 550°C and 800°C.

[0027] According to one or more embodiments, the alumina carrier in the form of an extruded product is 50 to 210 m 2 This indicates the specific surface area between / g.

[0028] According to one or more embodiments, the aluminum hydroxide or aluminum oxyhydroxide is hydraldilite.

[0029] According to one or more embodiments, the gasoline is gasoline obtained from a catalytic cracking unit. [Modes for carrying out the invention]

[0030] 1.Definition Next, the groups of chemical elements are given according to the CAS classification (CRC Handbook of Chemistry and Physics, edited by Dr. Lide, published by CRC Press, 81st edition, 2000-2001). For example, Group VIII according to the CAS classification corresponds to the metals in columns 8, 9, and 10 of the new IUPAC classification.

[0031] The total pore volume is measured by mercury porosimetry at a wetting angle of 140°, using, for example, an Autopore III® device under the Micromeritics® brand, in accordance with the standard ASTM D4284-92.

[0032] The BET specific surface area was measured by nitrogen physicoadsorption in accordance with standard ASTM D3663-03, a method described in the study “Adsorption by Powders & Porous Solids: Principles, Methodology and Applications”, Academic Press, 1999, by Rouquerol F., Rouquerol J., and Singh K.

[0033] The content of metals from Group VIII, Group VIb, and phosphorus is measured by X-ray fluorescence. 2. Explanation Preparation of the carrier The alumina support catalyst used in the method according to the present invention is obtained by rapidly dehydrating an aluminum hydroxide or aluminum oxyhydroxide type precursor, preferably a hydral dilite obtained from a process commonly known as the "Bayer" process. This method is described in detail, in particular, in the literature P. Euzen, P. Raybaud, X. Krokidis, H. Toulhoat, JL Le Loarer, JP Jolivet and C. Froidefond, Alumina, in Handbook of Porous Solids, edited by F. Schuth, KSW Sing and J. Weitkamp, ​​Wiley-VCH, Weinheim, Germany, 2002, pp. 1591-1677. This method makes it possible to produce alumina commonly known as "flash alumina".

[0034] According to a first alternative embodiment, the carrier used in the method according to the present invention is provided in the form of beads. Preparation of the carrier includes the following steps: s1) A step to obtain alumina powder, in which aluminum hydroxide or aluminum oxyhydroxide is dehydrated at a temperature between 400°C and 1200°C, preferably between 600°C and 900°C, for a time between 0.1 seconds and 5 seconds, preferably between 0.1 seconds and 4 seconds. s2) A step of forming the alumina powder obtained in step s1) into the form of beads, s3) A step of heat-treating the beads obtained in step s2) at a temperature of 200°C or higher, preferably between 200°C and 1200°C, more preferably between 300°C and 800°C, and even more preferably between 300°C and 750°C.

[0035] Step s1) is preferably carried out in the presence of a flow of high-temperature gas, such as dry air or humid air, so that evaporated water can be quickly removed and incorporated.

[0036] Aluminum hydroxide can be selected from hydraldrite, gibbsite, or bayerite. Aluminum oxyhydroxide can be selected from boehmite or diaspore.

[0037] Preferably, step s1) is carried out using hydral dilite.

[0038] It is preferable that step s1) is performed at least twice before step s2) is performed.

[0039] Preferably, the alumina powder obtained at the end of step s1) is pulverized to a particle size between 10 and 200 μm, and then molded in step s2).

[0040] Generally, the alumina powder obtained at the end of step s1) is washed with water or an acidic aqueous solution. When the washing step is carried out using an acidic aqueous solution, any inorganic or organic acid can be used; preferably, for inorganic acids, nitric acid or sulfuric acid; and for organic acids, carboxylic acids (formic acid, acetic acid, or malonic acid), sulfonic acids (para-toluenesulfonic acid), or sulfuric acid esters (lauryl sulfate) can be used.

[0041] The step s2) of forming the catalyst carrier in the form of beads is generally carried out by a rotation technique such as a rotary granulator or a rotary drum. By this type of process well-known to those skilled in the art called granulation, it is possible to obtain beads with controlled diameter and pore distribution, and these dimensions and pore distribution are generally formed during the agglomeration step. The pores can be created by various means such as the selection of the particle size distribution of the alumina powder or the agglomeration of a plurality of alumina powders having different particle size distributions. Preferably, the alumina carrier is formed in the form of beads, and its diameter is preferably between 0.8 and 10 mm, more preferably between 1 and 5 mm. Preferably, the forming step s2) is carried out to obtain alumina beads having an original packing density between 500 and 1100 kg / m 3 Preferably between 700 and 950 kg / m 3 and is carried out to obtain alumina beads having an original packing density between 700 and 950 kg / m.

[0042] According to an alternative sub-embodiment, another forming method for obtaining the carrier during the above step s2) consists of mixing, before or during the agglomeration step, the alumina powder obtained at the end of step s1) with one or more compounds called pore-forming compounds that disappear upon heating and as a result create pores in the beads. Examples of pore-forming compounds used can include, for example, wood powder, charcoal, carbon black, sulfur, tar, plastic or plastic emulsion, such as polyvinyl chloride, polyvinyl alcohol, naphthalene, etc. The amount of pore-forming compound added is determined by the desired volume.

[0043] According to step s3), the alumina powder formed in the form of beads is generally heat-treated at a temperature between 200 °C and above, preferably between 200 °C and 1200 °C, more preferably between 300 °C and 800 °C, and even more preferably between 300 °C and 750 °C for a time between 1 and 24 hours, preferably between 1 and 6 hours. At the end of step s3), the obtained alumina beads have a surface area between 50 and 420 m 2 / g, preferably between 60 and 350 m 2 / g, and even more preferably between 80 and 300 m 2It has a specific surface area between / g.

[0044] In an alternative embodiment of the present invention, in order to obtain aggregates, the alumina beads obtained at the end of step s3) are impregnated with water or an aqueous solution, preferably an acidic aqueous solution, and then subjected to a hydrothermal treatment step s4) by leaving the alumina beads in an autoclave at a temperature between 100°C and 300°C, preferably between 150°C and 250°C. The hydrothermal treatment step s4) is generally carried out at a temperature between 100°C and 300°C, preferably between 150°C and 250°C, for a time longer than 45 minutes, preferably between 1 hour and 24 hours, and very preferably between 1.5 hours and 12 hours. The hydrothermal treatment is generally carried out using an acidic aqueous solution containing one or more inorganic acids and / or organic acids, preferably nitric acid, hydrochloric acid, perchloric acid, sulfuric acid, and a weak acid whose solution has a pH of less than 4, such as acetic acid or formic acid. Generally, the acidic aqueous solution also includes one or more compounds that can release anions capable of binding with aluminum ions, preferably nitric acid (e.g., aluminum nitrate), chlorine, sulfuric acid, perchloric acid, chloroacetic acid, trichloroacetic acid, bromoacetic acid, or dibromoacetic acid ions, and compounds containing anions of the general formula R-COO, such as formic acid and acetic acid.

[0045] The aggregate obtained at the end of step s4) is then calcined in step s5) at a temperature between 500°C and 1100°C, preferably between 550°C and 1050°C, for a period of generally 1 to 24 hours, preferably between 1 to 6 hours. This calcination is generally carried out over a period of 50 to 210 m 2 Between / g, preferably 70 to 180m 2 Between / g, and even more preferably between 70 and 160m 2 This is carried out to obtain alumina beads having a specific surface area between / g.

[0046] According to a second alternative embodiment, the carrier used in the method according to the present invention is provided in the form of an extruded product. According to this second alternative embodiment, the preparation of the carrier includes the following steps: s1') A step to obtain an alumina-based material, dehydrating aluminum hydroxide or aluminum oxyhydroxide for a time of 0.1 to 5 seconds, preferably 0.1 to 4 seconds, at a temperature between 400°C and 1200°C, preferably between 600°C and 900°C. s2') A process of mixing and extruding the alumina-based material obtained at the end of step s1') in order to obtain an extruded material, s3') A process of heat treatment at a temperature of 200℃ or higher. s4') A step of hydrothermal treatment in which the material obtained at the end of step s3') is impregnated with water or an aqueous solution, preferably an acidic aqueous solution, and then left in an autoclave at a temperature between 100°C and 300°C, preferably between 150°C and 250°C. s5') A step in which the material obtained at the end of step s4') is fired at a temperature between 500°C and 1100°C, preferably between 550°C and 800°C.

[0047] Aluminum hydroxide can be selected from hydraldrite, gibbsite, or bayerite. Aluminum oxyhydroxide can be selected from boehmite or diaspore.

[0048] Preferably, step s1') is carried out by using hydral dilite.

[0049] In step s2'), one or more pore-forming materials are generally added, which disappear when heated during the molding of the alumina-based material. The pore-forming materials are selected from the group consisting of wood flour, charcoal, sulfur, tar, plastics, emulsions of plastics, polyvinyl alcohol, and naphthalene.

[0050] In step s3'), the extruded material obtained at the end of step s2') is generally heat-treated at a temperature of 200°C or higher, preferably between 200°C and 1200°C, preferably between 300°C and 800°C, and more preferably between 300°C and 750°C, for a period of 1 to 24 hours, preferably between 1 to 6 hours. The extruded material obtained at the end of step s3') is 50 to 420 m 2 Between / g, preferably 60 to 350m 2 Between / g, and even more preferably between 80 and 300m 2 It has a specific surface area between / g.

[0051] In step s4'), the hydrothermal treatment is generally carried out at a temperature of 100°C to 300°C, preferably 150°C to 250°C, for a time longer than 45 minutes, preferably between 1 hour and 24 hours, and very preferably between 1.5 hours and 12 hours. The hydrothermal treatment is generally carried out using an acidic aqueous solution containing one or more inorganic acids and / or organic acids, preferably nitric acid, hydrochloric acid, perchloric acid, sulfuric acid, and a weak acid whose solution has a pH of less than 4, such as acetic acid or formic acid. Generally, the acidic aqueous solution also contains one or more compounds that can release anions capable of binding with aluminum ions, preferably nitric acid (e.g., aluminum nitrate), chlorine, sulfuric acid, perchloric acid, chloroacetic acid, trichloroacetic acid, bromoacetic acid or dibromoacetic acid ions, and anions of the general formula R-COO, such as formic acid and acetic acid.

[0052] In step s5'), the material obtained at the end of step s4') is fired at a temperature between 500°C and 1100°C, preferably between 550°C and 1050°C, for a period of generally 1 to 24 hours, preferably between 1 to 6 hours. This firing generally lasts for 50 to 210 m 2 Between / g, preferably 70 to 180m 2 Between / g, and even more preferably between 70 and 160m 2 This process is carried out to obtain extruded alumina having a specific surface area between / g.

[0053] Therefore, at the end of the carrier preparation process: • If the carrier is provided in the form of beads and the preparation process does not include the hydrothermal treatment step s4) and the calcination step s5), the specific surface area of ​​the carrier is 50 to 420 m². 2 Between / g, preferably 60 to 350m 2 Between / g, and even more preferably between 80 and 300m 2 It is between / g; If the carrier is provided in the form of beads and the preparation process includes a hydrothermal treatment step s4) and a calcination step s5), the specific surface area of ​​the carrier is 50 to 210 m². 2 Between / g, preferably 70 to 180m 2 Between / g, and even more preferably between 70 and 160m 2 It is between / g; • If the carrier is provided in the form of an extruded product, the specific surface area of ​​the carrier is 50 to 210 m². 2 Between / g, preferably 70 to 180m 2 Between / g, and even more preferably between 70 and 160m 2 It is between / g.

[0054] The pore volume of the carrier is generally 0.4 cm³. 3 From 1.3cm / g 3 Between / g, preferably 0.4cm 3 From / g to 1.1cm 3 It is between / g. catalyst The catalyst used in the hydrogenodesulfurization method according to the present invention comprises an active phase formed from at least one metal from Group VIb, at least one metal from Group VIII, and phosphorus.

[0055] The metal from Group VIb present in the active phase of the catalyst is preferably selected from molybdenum and tungsten, with molybdenum being more preferred. The metal from Group VIII present in the active phase of the catalyst is preferably selected from cobalt, nickel, and mixtures of these two elements, with cobalt being more preferred.

[0056] Generally, the total content of metals from Group VIII, expressed in oxide form, is between 0.3% to 10% by weight, preferably between 0.4% to 8% by weight, more preferably between 0.45% to 7% by weight, most preferably between 0.5% to 6% by weight, and even more preferably between 0.5% to 5% 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.

[0057] Generally, the content of metals from Group VIb is expressed in the form of oxides and is between 1% to 30% by weight, preferably between 2% to 20% by weight, preferably between 2% to 15% by weight, and most preferably between 3% 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.

[0058] The molar ratio of the metal from Group VIII to the metal from Group VIb of the catalyst is generally between 0.1 and 0.8, preferably between 0.2 and 0.6, preferably between 0.3 and 0.5, and more preferably between 0.35 and 0.45.

[0059] The phosphorus content is generally between 0.1% to 10% by weight, preferably between 0.3% to 5% by weight, and more preferably between 0.4% to 3% by weight, relative to the total weight of the catalyst.

[0060] The molar ratio of phosphorus to metals from Group VIb is between 0.2 and 0.35, preferably between 0.23 and 0.35, and more preferably between 0.25 and 0.35.

[0061] If the carrier is provided in the form of beads and the preparation process does not include the hydrothermal treatment step s4) and the calcination step s5), the specific surface area of ​​the catalyst is 40 to 350 m². 2 Between / g, preferably 50 to 330m 2 Between / g, and even more preferably between 70 and 300m 2 It is between / g.

[0062] If the carrier is provided in the form of beads and the preparation process includes a hydrothermal treatment step s4) and a calcination step s5), the specific surface area of ​​the catalyst is 60 to 170 m². 2 Between / g, and even more preferably between 60 and 150m 2 It is between / g.

[0063] When the carrier is provided in the form of an extruded product, the specific surface area of ​​the catalyst is 60 to 170 m². 2 Between / g, and even more preferably between 60 and 150m 2 It is between / g. Catalyst preparation The introduction of the active phase to the support can be carried out by any preparation method known to those skilled in the art. The addition of the active phase to the support consists of contacting the support with at least one metal component from Group VIb, at least one metal component from Group VIII, and phosphorus in order to obtain a catalyst precursor.

[0064] According to the first embodiment, the components of metals from Group VIb, metals from Group VIII, and phosphorus are deposited on the carrier by one or more co-impregnation steps, i.e., the components of metals from Group VIb, metals from Group VIII, and phosphorus are introduced into the carrier simultaneously. The co-impregnation step(s) are preferably carried out by dry impregnation or by over-impregnation of solution. If the first embodiment includes the implementation of several co-impregnation steps, each co-impregnation step is preferably followed by an intermediate drying step for 0.5 to 24 hours, preferably 0.5 to 12 hours, at a temperature generally below 200°C, preferably between 50 and 180°C, more preferably between 60 and 150°C, and most preferably between 75 and 140°C.

[0065] According to a preferred embodiment of co-impregnation, the impregnation solution is preferably an aqueous solution. Preferably, the aqueous impregnation solution, if it contains cobalt, molybdenum, and phosphorus, is prepared under pH conditions that promote the formation of heteropolyanions in the solution. For example, the pH of such an aqueous solution is between 1 and 5.

[0066] According to the second embodiment, the catalyst precursor is prepared by sequentially depositing metal components from Group VIb, metal components from Group VIII, and phosphorus on the support in any order. Deposition can be carried out by dry impregnation, over-impregnation, or deposition / precipitation by methods well known to those skilled in the art. In this second embodiment, the deposition of metal components from Group VIb and VIII and phosphorus can be carried out by several impregnations having an intermediate drying step of 0.5 to 24 hours, preferably 0.5 to 12 hours, at a temperature generally below 200°C, preferably between 50 and 180°C, more preferably between 60 and 150°C, and very preferably between 75 and 140°C, between two sequential impregnations.

[0067] Regardless of the deposition mode of the metal and phosphorus used, the solvent involved in the composition of the impregnation solution, such as water or an organic solvent (e.g., alcohol), is selected to dissolve the metal precursor in the active phase.

[0068] For example, among the sources of molybdenum 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 their salts, optionally silicomolybdic acid (H4SiMo 12 O 40 ) and its salts can be used. The source of molybdenum can also be any heteropoly compound of the Keggin, cavity Keggin, substituted Keggin, Dawson, Anderson, or Strandberg type, for example. Preferably, molybdenum trioxide, as well as heteropoly compounds of the Keggin, cavity Keggin, substituted Keggin, and Strandberg type, are used.

[0069] The tungsten precursors that can be used are also well known to those skilled in the art. For example, among the oxides and hydroxides of tungsten, 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 12 O 40 ) and its salts can be used. The source of tungsten can also be any heteropoly compound of the Keggin, cavity Keggin, substituted Keggin, or Dawson type, for example. Preferably, oxides and ammonium salts, such as ammonium metatungstate, or heteropolyanions of the Keggin, cavity Keggin, or substituted Keggin type are used.

[0070] The cobalt precursors that can be used are preferably selected from, for example, oxides, hydroxides, hydroxycarbonates, carbonates, and nitrates. Preferably, cobalt hydroxide and cobalt carbonate are used.

[0071] The nickel precursors that can be used are preferably selected from, for example, oxides, hydroxides, hydroxycarbonates, carbonates, and nitrates. Preferably, nickel hydroxide and nickel hydroxycarbonate are used.

[0072] Phosphorus can preferably be introduced into the catalyst in various ways at various steps in its preparation. Phosphorus can be introduced during the molding of the alumina support, or preferably after this molding. Preferably, it can be introduced alone or as a mixture with at least one of a metal from Group VIb and a metal from Group VIII. Phosphorus is preferably introduced completely or partially onto the molded alumina support by dry impregnation of the alumina support using a solution containing a metal precursor and a phosphorus precursor, as a mixture with precursors of a metal from Group VIb and a metal from Group VIII. A preferred source of phosphorus is orthophosphate H3PO4, but its salts and esters, such as ammonium phosphate or mixtures thereof, are also suitable. Phosphorus can also be introduced simultaneously with other elements from Group VIb in the form of, for example, Keggin, void Keggin, substituted Keggin, or Strandberg-type heteropolyanions.

[0073] After the step(s) of contacting a metal from Group VIII, a metal from Group VIb, and phosphorus with a support are completed, the catalyst precursor is subjected to a dry step carried out by any technique known to those skilled in the art. Preferably, this step is carried out under atmospheric pressure or under reduced pressure. Preferably, this step is carried out under atmospheric pressure. This step is carried out at a temperature of less than 200°C, preferably between 50°C and 180°C, preferably between 60°C and 150°C, and very preferably between 75°C and 140°C.

[0074] The dry process is preferably carried out on a traversed bed using air or any other high-temperature gas. Preferably, when drying is carried out on a traversed bed, the gas used is either air or an inert gas, such as argon or nitrogen. Most preferably, drying is carried out on a traversed bed in the presence of air.

[0075] Preferably, this drying process is sustained for 30 minutes to 24 hours, preferably for 1 to 12 hours.

[0076] At the end of the drying process, a dried catalyst is obtained, which can be used as a hydrogenation catalyst after the activation process (sulfidation process).

[0077] In an alternative embodiment, the dry catalyst can then be subjected to a calcination process, for example, at a temperature of 200°C or higher under air. The calcination is generally carried out at a temperature of 600°C or lower, preferably between 200°C and 600°C, and particularly preferably between 250°C and 500°C. The calcination time is generally between 0.5 hours and 16 hours, preferably between 1 hour and 6 hours. The calcination is generally carried out under air. The calcination makes it possible to convert metal precursors from Group VIb and Group VIII into oxides.

[0078] Before use as a hydrogenation catalyst, it is preferable to subject the dried, or optionally calcined, catalyst to a sulfidation step (activation step). This activation step is preferably carried out in a sulfo-reducing atmosphere in the presence of hydrogen and hydrogen sulfide, by a method well known to those skilled in the art. Hydrogen sulfide can be used directly or generated by a sulfidating agent (e.g., dimethyl disulfide). Process for hydrodesulfurization of gasoline The hydrogenation process involves contacting a sulfur-containing olefin gasoline fraction with the catalyst and hydrogen described above under the following conditions: • The temperature is between 200°C and 400°C, preferably between 230°C and 330°C. • The total pressure is between 1 and 3 MPa, preferably between 1.5 and 2.5 MPa. • The space velocity per hour (HSV), defined as the flow rate of the raw material volume relative to the catalyst volume, is between 1 and 10 h. -1 Preferably 2 to 6 hours -1 During The volume ratio of hydrogen / gasoline raw materials is between 100 and 600 Sl / l, preferably between 200 and 400 Sl / l.

[0079] Therefore, the method according to the present invention makes it possible to process any type of sulfur-containing olefin gasoline fraction, such as fractions obtained from coking, bisque breaking, steam cracking, or catalytic cracking (FCC, fluid catalytic cracking) units. This gasoline can optionally consist mostly of gasoline derived from other production processes, such as atmospheric distillation (gasoline obtained from direct distillation (or straight-run gasoline)) or conversion processes (coking or steam cracking gasoline). The raw material preferably consists of a gasoline fraction obtained from a catalytic cracking unit.

[0080] The raw material is preferably a gasoline fraction containing a sulfur-containing compound and an olefin, and having a boiling point between 30°C and less than 250°C, preferably between 35°C and 240°C, and in a preferred embodiment between 40°C and 220°C.

[0081] The sulfur content of gasoline fractions produced by catalytic cracking (FCC) depends on the sulfur content of the raw materials processed by the FCC, whether or not the FCC raw materials are pretreated, and the endpoint of the fraction. Generally, the sulfur content of the entire gasoline fraction, especially that derived from FCC, is greater than 100 ppm by weight, and in most cases greater than 500 ppm by weight. For gasoline whose endpoint is above 200°C, the sulfur content is often greater than 1,000 ppm by weight, and in some cases can even reach 4,000 to 5,000 ppm by weight.

[0082] Furthermore, the gasoline obtained from the catalytic cracking (FCC) unit contains, on average, 0.5% to 5% by weight of diolefins, 20% to 50% by weight of olefins, and 10 ppm to 0.5% by weight of sulfur, and generally contains less than 300 ppm of mercaptans. Mercaptans are generally concentrated in the light fraction of gasoline, more specifically in the fraction with a boiling point below 120°C.

[0083] It should be noted that sulfur-containing compounds present in gasoline may include heterocyclic sulfur-containing compounds, such as thiophenes, alkylthiophenes, or benzothiophenes. Unlike mercaptans, these heterocyclic compounds cannot be removed by extraction processes. These sulfur-containing compounds are removed by hydrogenation, which results in a conversion to hydrocarbons and H2S.

[0084] Preferably, the gasoline treated by the process according to the present invention is heavy gasoline (or HCN from heavy cracked naphtha) obtained from a distillation step aimed at separating the broadcut (or FRCN from full-range cracked naphtha) of gasoline obtained from a cracking process into light gasoline (LCN from light cracked naphtha) and heavy gasoline (HCN). The cut points for the light and heavy gasoline are determined to limit the sulfur content of the light gasoline and, preferably, to allow it to be used in a gasoline pool without additional post-treatment. The broadcut FRCN is subjected to a selective hydrogenation step prior to the distillation step. [Examples]

[0085] [Examples]

[0086] Catalyst A (according to the present invention) The carrier S1 of catalyst A, provided in bead form, is obtained by dehydration by flash firing of hydraulic dilite (Emplura®, Merck®) to obtain activated alumina powder. A high-temperature gas flow allows for extremely rapid removal and entrainment of evaporated water. The temperature is set to 800°C, and the contact time between the material being dehydrated and the gas is 1 second. The resulting activated alumina powder is pulverized to a particle size between 10 and 200 μm and then washed with water. The alumina powder is then formed into beads by a granulator. The amount of carbon black (N990, Thermax®) after sieving is 785 kg / m³. 3The raw packing density is adjusted to obtain beads with a diameter between 2 and 4 mm. After heat treatment at 720°C for 2 hours, the beads are 200 m 2 The specific surface area per g is shown. Subsequently, the beads are subjected to a hydrothermal treatment by impregnating them with an acidic aqueous solution. The hydrothermal treatment is carried out in a rotary basket autoclave at a temperature of 200°C for 6.5 hours, and the impregnation solution is an acidic aqueous solution containing aluminum nitrate (0.1N, Merck®). The resulting aggregates are then calcined at a temperature of 650°C for 2 hours. 146m 2 Specific surface area and 0.99 cm² / g 3 A bead-shaped alumina carrier S1 with a total pore volume of / g is obtained.

[0087] The carrier S1 exhibits a water absorption capacity of 0.95 ml / g. The impregnation solution is prepared by heating 1.15 grams of molybdenum oxide (MoO3 > 99.5%, Merck®), 0.30 grams of cobalt hydroxide (95% Co(OH)2, Merck®), and 0.26 grams of phosphoric acid (85% H3PO4, Merck®) in 9.3 ml of distilled water at 90°C for 3 hours. 10 grams of the carrier is dry-impregnated and aged in a moisture-saturated atmosphere for 12 hours, after which the solid is dried at 120°C for 12 hours. Subsequently, the solid is calcined in air at 450°C for 2 hours. The resulting catalyst A has 2.0 wt% CoO, 10 wt% MoO3, and 1.4 wt% P2O5 relative to the total weight of the catalyst, i.e., a Co / Mo atomic ratio of 0.38 and a P / Mo atomic ratio of 0.28. Catalyst A has a total pore volume of 0.84 ml / g and 118 m 2 It has a specific surface area of ​​ / g. The metal content is measured in oxide form and is shown in Table 1 below. [Examples]

[0088] Catalyst B (according to the present invention) The carrier S2 for catalyst B, provided in bead form, is obtained by flash calcining and dehydrating hydral dilite (Emplura®, Merck®) to obtain activated alumina powder. A high-temperature gas flow allows for extremely rapid removal and incorporation 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 pulverized to a particle size between 10 and 200 μm and then washed with water. The alumina powder is then formed into beads by a granulator. After sieving, the beads are granulated to 785 kg / m³. 3 It has a raw packing density and a diameter between 2 and 4 mm. After heat treatment at 720°C for 2 hours, 200 m 2 Specific surface area and 0.75 cm² per g 3 A bead-shaped alumina support S2 is obtained that exhibits the total pore volume per g.

[0089] The carrier S2 exhibits a water absorption capacity of 0.73 ml / g. The impregnation solution is prepared by heating 1.15 g of molybdenum oxide (MoO3 > 99.5%, Merck®), 0.30 g of cobalt hydroxide (95% Co(OH)2, Merck®), and 0.26 g of phosphoric acid (85% H3PO4, Merck®) in 7.1 ml of distilled water at 90°C for 3 hours. 10 g of the carrier is dry-impregnated and aged in a moisture-saturated atmosphere for 12 hours, after which the solid is dried at 120°C for 12 hours. The solid is then calcined in air at 450°C for 2 hours. The resulting catalyst B has 2.0 wt% CoO, 10 wt% MoO3, and 1.4 wt% P2O5 relative to the total weight of the catalyst, i.e., a Co / Mo atomic ratio of 0.38 and a P / Mo atomic ratio of 0.28. Catalyst B has a total pore volume of 0.65 ml / g and 118 m 2 It has a specific surface area of ​​ / g. The metal content is measured in oxide form and is shown in Table 1 below. [Examples]

[0090] Catalyst C (not according to the present invention) In examples not based on this invention, the P / Mo ratio is less than 0.2.

[0091] Catalyst C is prepared on support S1 according to Example 1. The impregnation solution is prepared by heating 1.15 grams of molybdenum oxide (MoO3 > 99.5%, Merck®), 0.30 grams of cobalt hydroxide (95% Co(OH)2, Merck®), and 0.14 grams of phosphoric acid (85% H3PO4, Merck®) in 9.3 ml of distilled water at 90°C for 3 hours. 10 grams of support is dry-impregnated and aged in a moisture-saturated atmosphere for 12 hours, after which the solid is dried at 120°C for 12 hours. The solid is then calcined in air at 450°C for 2 hours. The resulting catalyst C contains 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. Catalyst C has a total pore volume of 0.85 ml / g and 120 m 2 It has a specific surface area of ​​ / g. The metal content is measured in oxide form and is shown in Table 1 below. [Examples]

[0092] Catalyst D (not according to the present invention) In examples not according to this invention, the P / Mo ratio is greater than 0.35.

[0093] Catalyst D is prepared on support S1 according to Example 1. The impregnation solution is prepared by heating 1.15 grams of molybdenum oxide (MoO3 > 99.5%, Merck®), 0.30 grams of cobalt hydroxide (95% Co(OH)2, Merck®), and 0.48 grams of phosphoric acid (85% H3PO4, Merck®) in 9.3 ml of distilled water at 90°C for 3 hours. Dry impregnation of 10 grams of support. After aging in a moisture-saturated atmosphere for 12 hours, the solid is dried at 120°C for 12 hours. The solid is then calcined in air at 450°C for 2 hours. The resulting catalyst D has 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. Catalyst D has a total pore volume of 0.82 ml / g and 117 m 2It has a specific surface area of ​​ / g. The metal content is measured in oxide form and is shown in Table 1 below. [Examples]

[0094] Catalyst E (not according to the present invention) In examples not based on this invention, the alumina support is not obtained by dehydration of aluminum hydroxide or aluminum oxyhydroxide.

[0095] The carrier S4, provided in the form of an extruded product, is obtained by kneading boehmite powder (Sasol®) in a sealed container of an MX-type double Z-arm kneader (Guittard®). A peptizing agent (nitric acid, HNO3) is added up to 4 g per 100 g of boehmite. Water is gradually introduced so that the ignition loss is approximately 50%, and this value is adjusted to obtain a homogeneous, viscous paste. This paste is then extruded through a 1.8 mm diameter die using a piston extruder. The resulting extruded product is dried at 120°C for 12 hours, and then calcined at 900°C for 2 hours. The resulting extruded product is 140 m 2 Specific surface area of ​​ / g and 0.73 cm² 3 This indicates the total pore volume per g.

[0096] The carrier S4 exhibits a water absorption capacity of 0.72 ml / g. The impregnation solution is prepared by heating 1.15 g of molybdenum oxide (MoO3 > 99.5%, Merck®), 0.30 g of cobalt hydroxide (95% Co(OH)2, Merck®), and 0.26 g of phosphoric acid (85% H3PO4, Merck®) in 7.0 ml of distilled water at 90°C for 3 hours. 10 g of the carrier is dry-impregnated and aged in a moisture-saturated atmosphere for 12 hours, after which the solid is dried at 120°C for 12 hours. The solid is then calcined in air at 450°C for 2 hours. The resulting catalyst E has 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. Catalyst E has a total pore volume of 0.63 ml / g and 118 m 2It has a specific surface area of ​​ / g. The metal content is measured in oxide form and is shown in Table 1 below.

[0097] [Table 1] [Examples]

[0098] Evaluation of the performance quality of catalysts used in hydrodesulfurization reactors. A typical model feedstock of catalytic cracking gasoline containing 10% by weight of 2,3-dimethylbuta-2-ene and 0.33% by weight of 3-methylthiophene (i.e., 1000 ppm by weight of sulfur in the feedstock) is used to evaluate the catalytic performance quality of various catalysts. The solvent used is heptane.

[0099] Hydrodesulfurization (HDS) is carried out in a fixed transverse-bed reactor at a total pressure of 1.5 MPa and 210°C in the presence of 4 ml of catalyst, with HSV = 6h -1 The reaction is carried out using (HSV = volumetric flow rate of raw materials / volumetric flow rate of catalyst) and an H2 / volume ratio of 300 Sl / l of raw materials. Prior to the HDS reaction, the catalyst is sulfurized in situ at 350°C for 2 hours under a hydrogen gas stream containing 15 mol% H2S at atmospheric pressure.

[0100] Each catalyst is placed in a series within the reactor. Samples are taken at different time intervals and analyzed by gas chromatography to observe the disappearance of reactants and the formation of products.

[0101] The catalytic performance quality of a catalyst is evaluated in terms of catalytic activity and selectivity. Hydrodesulfurization (HDS) activity is standardized by the amount of catalyst introduced and expressed from the HDS reaction rate constant (kHDS) of 3-methylthiophene, assuming a first-order kinetic theory for sulfur-containing compounds. The hydrogenation activity of olefins (HydO) is standardized by the amount of catalyst introduced and expressed from the rate constant of the hydrogenation reaction of 2,3-dimethylbuta-2-ene, assuming a first-order kinetic theory for olefins.

[0102] Catalyst selectivity is expressed by the standardized ratio of the rate constant kHDS / kHydO. The kHDS / kHydO ratio increases as catalyst selectivity increases. The obtained value is standardized by adopting catalyst A as the baseline (relative HDS activity and relative selectivity equal to 100). Therefore, the performance quality is relative HDS activity and relative selectivity.

[0103] [Table 2]

[0104] The simultaneous improvement in the activity and selectivity of the catalyst according to the present invention is particularly suitable for use in a hydrodesulfurization method for gasoline containing olefins, which aims to limit the loss of octane number due to the hydrogenation of olefins as much as possible.

Claims

1. A method for hydrodesulfurizing a sulfur-containing olefin-based gasoline fraction, comprising contacting the sulfur-containing olefin-based gasoline fraction with hydrogen and a catalyst, wherein the hydrodesulfurizing method is performed at a temperature between 200°C and 400°C, a total pressure between 1 and 3 MPa, and a space velocity per hour defined as the flow rate of the volume of raw materials relative to the volume of catalyst between 1 and 10 h⁻¹. －１ The method is carried out between and with a hydrogen / gasoline fraction volume ratio between 100 and 600 Sl / l, wherein the catalyst comprises an alumina support obtained by dehydrating aluminum hydroxide or aluminum oxyhydroxide for a time between 0.1 and 5 seconds at a temperature between 400 and 1200°C, 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 between 0.2 and 0.

35.

2. The method according to claim 1, wherein the molar ratio of phosphorus to the metal from group VIb is between 0.23 and 0.

35.

3. The method according to claim 1 or 2, wherein the molar ratio of the metal from Group VIII to the metal from Group VIb of the catalyst is between 0.1 and 0.

8.

4. The method according to any one of claims 1 to 3, wherein the content of the metal from Group VIb of the catalyst, expressed in the form of an oxide, is between 1% by weight and 30% by weight relative to the total weight of the catalyst.

5. The method according to any one of claims 1 to 4, wherein the content of the metal from Group VIII of the catalyst, represented in the form of an oxide, is between 0.3% by weight and 10% by weight relative to the total weight of the catalyst.

6. P ２ O ５ The method according to any one of claims 1 to 5, wherein the phosphorus content, expressed in the form of , is between 0.1% by weight and 10% by weight relative to the total weight of the catalyst.

7. The method according to any one of claims 1 to 6, wherein the metal from Group VIII is cobalt.

8. The method according to any one of claims 1 to 7, wherein the metal from group VIb is molybdenum.

9. The method according to any one of claims 1 to 8, wherein the alumina carrier is provided in the form of beads.

10. The alumina carrier in the form of beads is subjected to the following steps: s1) In order to obtain alumina powder, a step of dehydrating aluminum hydroxide or aluminum oxyhydroxide for a time between 0.1 seconds and 5 seconds at a temperature between 400°C and 1200°C. s2) A step of forming the alumina powder obtained in step s1) into the form of beads, s3) A step of heat-treating the beads obtained in step s2) at a temperature of 200°C or higher. The method according to claim 9, obtained by a preparation method comprising:

11. The alumina carrier in the form of beads is further subjected to the following steps: s4) A step of hydrothermally treating the material obtained at the end of step s3) by impregnating it with water or an aqueous solution and then keeping it in an autoclave at a temperature between 100°C and 300°C. s5) A step of firing the material obtained at the end of step s4) at a temperature between 500°C and 1100°C. The method according to claim 10, obtained by a preparation method comprising:

12. The alumina carrier in the form of beads is 50 to 420 m 2 The method according to claim 10, which shows the specific surface area between / g.

13. The alumina carrier in the form of beads is 50 to 210 m 2 The method according to claim 11, which shows the specific surface area between / g.

14. The method according to any one of claims 1 to 8, wherein the alumina carrier is provided in the form of an extruded product.

15. The alumina carrier in the form of an extruded product is subjected to the following steps: s1') In order to obtain an alumina-based material, a step is taken to dehydrate aluminum hydroxide or aluminum oxyhydroxide for a time between 0.1 seconds and 5 seconds at a temperature between 400°C and 1200°C. s2') A step of kneading and extruding the alumina-based material obtained at the end of step s1') in order to obtain an extruded material, s3') A process of heat treatment at a temperature of 200°C or higher. s4') A step of hydrothermally treating the material obtained at the end of step s3') by impregnating it with water or an aqueous solution, preferably an acidic aqueous solution, and then keeping it in an autoclave at a temperature between 100°C and 300°C. s5') A step of firing the material obtained at the end of step s4') at a temperature between 500°C and 1100°C. The method according to claim 14, obtained by a preparation method comprising:

16. The alumina carrier in the form of an extruded product is 50 to 210 m 2 The method according to claim 15, which shows the specific surface area between / g.

17. The method according to any one of claims 1 to 16, wherein the aluminum hydroxide or aluminum oxyhydroxide is hydraldirite.

18. The method according to any one of claims 1 to 17, wherein the gasoline is obtained from a catalytic cracking unit.

Images