Process for hydrodesulfurization of petroleum distillates using a catalyst comprising a graphite material characterized by its h / c ratio

Abstract

The present invention relates to a hydrodesulfurization process of petroleum distillates, wherein a petroleum distillate is contacted with hydrogen and a catalyst, said catalyst comprising an oxidic support, sulfur and an active phase, said active phase comprising at least one metal of group VIB and at least one metal of group VIII, said catalyst comprising in particular a graphitic material comprising carbon and hydrogen, the carbon content expressed in carbon element being comprised between 5 and 20% by weight relative to the weight of the catalyst, the H / C atomic ratio being less than 1.4, said graphitic material being free of oxygen.

Description

Invention Field

[0001] The present invention relates to a method for hydrodesulfurizing gasoline fractions using a catalyst comprising a graphite material, wherein the graphite material is characterized by its H / C ratio. Existing technology

[0002] Sulfur is a naturally occurring element in crude oil, and therefore, if not removed during refining, it remains in gasoline and diesel fuels. However, sulfur in gasoline interferes with the efficiency of emission reduction systems (catalytic converters) and contributes to air pollution. To combat environmental pollution, all countries have therefore gradually adopted strict sulfur standards, such as 10 ppm (by weight) of sulfur in commercial gasoline in Europe, China, the United States, and Japan. The issue of reducing sulfur content primarily focuses on gasoline obtained through cracking (whether catalytic cracking (FCC, fluid catalytic cracking) or non-catalytic cracking (coking, viscous cracking, steam cracking)) (the main precursor of sulfur in the gasoline pool).

[0003] One solution 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 decrease 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 such gasoline (which occurs simultaneously with hydrodesulfurization).

[0004] Unlike other hydrotreating methods, especially those for gas oil-type feedstocks, gasoline hydrodesulfurization must therefore address the contradictory dual constraints of providing extreme hydrodesulfurization of gasoline and limiting the presence of unsaturated compounds.

[0005] The most widely used approach to address the aforementioned dual problems lies in employing a method in which the sequence of unit stages allows for the simultaneous maximization of hydrodesulfurization while limiting olefin hydrogenation. Thus, recent methods, such as the Prime G+ (trademarked) method, enable the desulfurization of olefin-rich cracked gasoline while limiting the hydrogenation of single olefins and the resulting octane number loss and high hydrogen consumption. Such methods are described, for example, in patent applications EP 1077247 and EP 1174485.

[0006] Therefore, achieving the desired reaction selectivity (the ratio of hydrodesulfurization to olefin hydrogenation) may be partly attributed to the choice of method, but in all cases, the use of an inherently selective catalytic system is often the key factor. Typically, catalysts used for these applications are sulfide-type catalysts containing Group VIb elements (Cr, Mo, W) and Group VIII elements (Fe, Ru, Os, Co, Rh, Ir, Pd, Ni, Pt). Such catalysts are disclosed, for example, in documents US5985136, US4140626, US4774220, US8637423, and EP1892039, which describe selective hydrodesulfurization catalysts.

[0007] Therefore, refineries are currently very interested in the hydrodesulfurization method for gasoline fractions, which has shown that it maintains catalytic activity while significantly improving the selectivity of catalytic performance.

[0008] It is known that the presence of carbon in catalysts used for hydrodesulfurization of gasoline fractions can improve selectivity. Therefore, US2793170 describes a method for hydrodesulfurization of cracked gasoline in the presence of a catalyst containing 0.2% to 6% by weight of carbon. FR2850299 describes a method for hydrodesulfurization of cracked gasoline in the presence of a catalyst with a carbon content of less than or equal to 2.8% by weight.

[0009] Document EP0745660 describes a method for hydrodesulfurizing olefin gasoline fractions using a catalyst pre-coked on a surface, wherein the carbon content is 3% to 10% by weight relative to the weight of the catalyst, and the C / H atomic ratio in the coke is ≤0.7 (=H / C ratio ≥1.42).

[0010] Document US2009 / 0258780, in part, describes a catalyst comprising a metal selected from Group VIII, molybdenum (Mo), phosphorus, and sulfur supported on a porous inorganic oxide support comprising a carbon-containing material, which enables an increase in selectivity to be observed in a gasoline hydrodesulfurization process. The carbon-containing material must contain oxygen, characterized by a carbon content of 5% to 20% by weight relative to the weight of the support, an atomic ratio of hydrogen to carbon (H / C) of 0.4 to 1.0, and an atomic ratio of oxygen to carbon (O / C) of 0.1 to 0.6.

[0011] These latter two papers suggest that not only the content of carbon-containing materials but also their chemical properties appear to influence the selectivity of this method.

[0012] Therefore, the present invention relates to a hydrodesulfurization method for gasoline fractions, the purpose of which is to maintain hydrodesulfurization activity and significantly improve selectivity by using a catalyst containing graphite material, wherein the graphite material is characterized by its H / C ratio and is oxygen-free.

[0013] Invention Theme

[0014] This invention relates to a method for hydrodesulfurizing a gasoline fraction containing sulfur compounds and olefins, wherein the gasoline fraction, hydrogen, and a catalyst are contacted, and the method is carried out at a temperature of 200°C to 400°C, a total pressure of 1 to 3 MPa, and for 1 to 10 hours. -1 The experiment was conducted at a space velocity of 100 to 1200 Sl / l and a hydrogen / gasoline feedstock volume ratio, wherein the space velocity is defined as the volumetric flow rate of the feedstock relative to the volume of the catalyst. The catalyst comprises an oxide support, sulfur, and an active phase, wherein the active phase comprises at least one Group VIb metal and at least one Group VIII metal. The catalyst also comprises a carbon- and hydrogen-containing graphite material, wherein the carbon content, expressed as carbon element, is 5% to 20% by weight relative to the weight of the catalyst, the H / C atomic ratio is less than 1.4, and the graphite material is oxygen-free.

[0015] This is because it has been found that using catalysts containing sulfur and graphite materials, which have a relatively high carbon content and an H / C atomic ratio of less than 1.4 and are oxygen-free, can result in a significant increase in selectivity in the selective hydrodesulfurization process of gasoline fractions, without any loss of activity.

[0016] Specifically, without being bound by any theory, the presence of sulfur and such graphite materials in the catalyst appears to promote metal dispersion within the support, thus avoiding the pH rise typically observed during solution impregnation containing metal precursors in the absence of graphite materials. Therefore, maintaining a relatively low pH allows for the possible presence of heteropolyanions that could impair monomolybdate and polymolybdate entities, which promote sulfidation of the metal entities and the formation of more selective sulfide phases.

[0017] The use of catalysts containing graphite materials also makes it possible to avoid or mitigate thermal runaway during hydrodesulfurization processes, which are characterized by highly exothermic reactions.

[0018] According to an alternative form, the carbon content, expressed in carbon elements, is 10% to 15% by weight relative to the weight of the catalyst.

[0019] According to an alternative form, the sulfur content, expressed in elemental form, is 1% to 8% by weight relative to the weight of the catalyst.

[0020] According to one alternative form, the H / C atomic ratio is 0.8 to 1.2.

[0021] According to an alternative form, the catalyst has a Group VIb metal content of 5% to 40% by weight relative to the total weight of the catalyst, expressed as Group VIb metal oxides, and a Group VIII metal content of 1% to 10% by weight relative to the total weight of the catalyst, expressed as Group VIII metal oxides.

[0022] According to one alternative formulation, the molar ratio of Group VIII metals to Group VIb metals in the catalyst is 0.1 to 0.8.

[0023] According to an alternative form, the catalyst has a specific surface area of ​​20 to 200 m². 2 / g.

[0024] According to an alternative form, the catalyst also contains phosphorus, expressed as P2O5, in an amount of 0.1% to 20% by weight relative to the total weight of the catalyst.

[0025] According to an alternative form, the catalyst also contains an organic compound containing oxygen and / or nitrogen and / or sulfur.

[0026] According to this alternative form, the organic compound is selected from compounds containing one or more chemical functional groups selected from carboxyl, alcohol, thiol, thioether, sulfone, sulfoxide, ether, aldehyde, ketone, ester, carbonate, amine, nitrile, imide, oxime, urea, or amide functional groups, or compounds containing a furan ring or sugar. More specifically, the organic compound is selected from γ-valerolactone, 2-acetylbutyrolactone, triethylene glycol, diethylene glycol, ethylene glycol, ethylenediaminetetraacetic acid (EDTA), and maleic anhydride. Acids, malonic acid, citric acid, acetic acid, oxalic acid, gluconic acid, glucose, fructose, sucrose, sorbitol, xylitol, γ-ketovalerate, di(C1-C4) esters of succinate and more particularly dimethyl succinate, dimethylformamide, 1-methyl-2-pyrrolidone, propylene carbonate, 2-methoxyethyl ester of 3-oxobutyrate, N,N-bis(2-hydroxyethyl)glycine, tris(hydroxymethyl)methylglycine ne), 2-furfural (also known by the name furfural), 5-hydroxymethylfurfural, 2-acetylfuran, 5-methyl-2-furfural, ascorbic acid, butyl lactate, ethyl lactate, butyryl butyl lactate, ethyl 3-hydroxybutyrate, ethyl 3-ethoxypropionate, 2-ethoxyethyl acetate, 2-butoxyethyl acetate, 2-hydroxyethyl acrylate, 1-vinyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolium Alkyl ketones, 1,5-pentanediol, 1-(2-hydroxyethyl)-2-pyrrolidone, 1-(2-hydroxyethyl)-2,5-pyrrolidone, 5-methyl-2(3H)-furanone, 1-methyl-2-piperidinone, 4-aminobutyric acid, butyl glycolate, ethyl 2-mercaptopropionate, ethyl 4-oxovalerate, diethyl maleate, dimethyl maleate, dimethyl fumarate, diethyl fumarate, dimethyl adipate, and dimethyl 3-oxoglutarate.

[0027] According to one alternative form, the active phase of the catalyst consists of cobalt and molybdenum.

[0028] According to an alternative form, the catalyst is prepared according to a preparation method comprising the following stages:

[0029] a) Contacting at least one hydrocarbon and at least one sulfur-containing compound with the oxide support such that the carbon- and hydrogen-containing graphite material can be formed on the oxide support.

[0030] b) Then, the compound containing a Group VIb metal and the compound containing a Group VIII metal, as well as optionally phosphorus and / or at least one oxygen- and / or nitrogen- and / or sulfur-containing organic compound, are contacted with the oxide support containing the graphite material.

[0031] To obtain catalytic precursors,

[0032] c) The catalytic precursor is dried at a temperature below 200°C without subsequent calcination to obtain a dried catalyst.

[0033] d) Optionally, the dried catalyst is activated in the presence of a sulfiding agent.

[0034] According to another alternative, the catalyst is a partially used catalyst produced by a hydrotreating process.

[0035] According to one alternative form, gasoline is catalytic cracking gasoline.

[0036] definition

[0037] Subsequently, chemical elements are assigned groups 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 metals in columns 8, 9, and 10 according to the new IUPAC classification.

[0038] The term "specific surface area" should be understood as the BET specific surface area (S) determined by nitrogen adsorption according to the standard ASTM D 3663-78 established by the Brunauer-Emmett-Teller method described in "The Journal of American Chemical Society", 1938, 60, 309. BET , with m 2 (in units of g).

[0039] The total pore volume of a catalyst or support used to prepare a catalyst should be understood as the volume measured by mercury porosimetry at a maximum pressure of 4000 bar (400 MPa), using a surface tension of 484 dynes / cm and a contact angle of 140°, according to standard ASTM D4284-83. Following the recommendation in the publication "Techniques de l'ingénieur, traité analyze et caractérisation" [Techniques of the Engineer, Analysis and Characterization Treatise], pp. 1050-1055, the wetting angle used should be equal to 140°. For better accuracy, the total pore volume value corresponds to the total pore volume measured by mercury porosimetry on the sample minus the total pore volume measured by mercury porosimetry on the same sample at a pressure corresponding to 30 psi (approximately 0.2 MPa).

[0040] The content of Group VIII and Group VIb metals was measured by X-ray fluorescence method.

[0041] The contents of Group VIb metals, Group VIII metals, and phosphorus in the catalyst are expressed as oxides corrected for the loss on ignition of the catalyst sample after two hours in a muffle furnace at 550°C. Loss on ignition is due to moisture loss and was determined according to ASTM D7348. Invention Details

[0043] This invention relates to a method for hydrodesulfurizing a gasoline fraction containing sulfur compounds and olefins, wherein the gasoline fraction, hydrogen, and a catalyst are contacted, and the method is carried out at a temperature of 200°C to 400°C, a total pressure of 1 to 3 MPa, and for 1 to 10 hours. -1 The experiment was conducted at a space velocity of 100 to 1200 Sl / l and a hydrogen / gasoline feedstock volume ratio, wherein the space velocity is defined as the volumetric flow rate of the feedstock relative to the volume of the catalyst. The catalyst comprises an oxide support, sulfur, and an active phase, wherein the active phase comprises at least one Group VIb metal and at least one Group VIII metal. The catalyst also comprises a carbon- and hydrogen-containing graphite material, wherein the carbon content, expressed as carbon element, is 5% to 20% by weight relative to the weight of the catalyst, the H / C atomic ratio is less than 1.4, and the graphite material is oxygen-free.

[0044] The hydrodesulfurization method according to the invention enables the conversion of organic sulfur compounds in gasoline fractions into hydrogen sulfide (H2S) while limiting the hydrogenation of olefins present in the fractions as much as possible.

[0045] Hydrodesulfurization involves contacting a gasoline fraction containing sulfur compounds and olefins with a catalyst and hydrogen under the following conditions:

[0046] Temperatures ranging from -200℃ to 400℃, preferably from 230℃ to 330℃;

[0047] -1 to 3 MPa, preferably 1.5 to 2.5 MPa total pressure;

[0048] -1 to 10h -1 Preferred time: 2 to 6 hours -1 The space velocity (HSV) is defined as the volumetric flow rate of the feedstock relative to the volume of the catalyst.

[0049] A hydrogen / gasoline feedstock volume ratio of -100 to 1200 Sl / l, preferably 150 to 400 Sl / l.

[0050] Catalytic hydrodesulfurization can be carried out in one or more fixed-bed or fluidized-bed reactors connected in series. If the method is carried out by at least two reactors connected in series, an apparatus can be provided for removing H2S from the effluent produced by the first hydrodesulfurization reactor before treating the effluent in the second hydrodesulfurization reactor. The operating conditions in the two reactors can be the same or different.

[0051] Raw materials to be processed

[0052] The method according to the invention enables the processing of any type of gasoline fraction containing sulfur compounds and olefins, such as fractions produced by coking, viscous cracking, steam cracking, or catalytic cracking (FCC, fluid catalytic cracking) units. The gasoline may optionally consist of significant fractions from gasoline produced by other methods (e.g., atmospheric distillation, gasoline produced by direct distillation (or straight-run gasoline)) or from conversion methods (coking or steam cracking gasoline). The feedstock is preferably composed of gasoline fractions produced by a catalytic cracking unit.

[0053] The feedstock is advantageously a gasoline fraction containing sulfur compounds and olefins, and has a boiling point of 30°C to less than 250°C, preferably 35°C to 240°C, and in a preferred manner 40°C to 220°C.

[0054] The sulfur content of gasoline fractions produced by catalytic cracking (FCC) depends on the sulfur content of the feedstock processed by FCC, whether FCC feedstock pretreatment was performed, and the fraction's endpoint. Typically, all gasoline fractions, especially those from FCC, have a sulfur content greater than 100 ppm by weight, and most often greater than 500 ppm by weight. For gasoline with an endpoint greater than 200°C, the sulfur content is usually greater than 1000 ppm by weight; in some cases, it can even reach values ​​on the order of 4000 to 5000 ppm by weight.

[0055] In addition, gasoline produced by catalytic cracking (FCC) units typically contains 0.5% to 5% by weight of dienes, 20% to 50% by weight of olefins, and 10 ppm to 0.5% by weight of sulfur, and usually includes less than 300 ppm of thiols. Thiols are generally concentrated in the lighter fractions of gasoline, more specifically, in fractions with boiling points below 120°C.

[0056] It should be noted that sulfur-containing compounds present in gasoline may also include heterocyclic sulfur-containing compounds, such as thiophene, alkylthiophene, or benzothiophene.

[0057] Preferably, the gasoline processed by the method according to the invention is heavy gasoline (or HCN, for heavy cracked naphtha) produced in a distillation stage, the purpose of which is to separate the wide-range fraction (or FRCN, for full-boiling-range cracked naphtha) of gasoline produced by cracking into light gasoline (LCN, for light cracked naphtha) and heavy gasoline HCN. Cut points for light and heavy gasoline are determined to limit the sulfur content of the light gasoline and make it usable in the gasoline pool, preferably without further post-treatment.

[0058] Advantageously, prior to the distillation stage, the wide FRCN fraction is subjected to a selective hydrogenation stage to at least partially hydrogenate the diene and carry out a reaction that increases the molecular weight of a portion of the sulfur-containing compounds.

[0059] For this purpose, the broad FRCN fraction is fed to a selective hydrogenation catalytic reactor, which contains at least one fixed or moving bed of catalysts for the selective hydrogenation of dienes and for increasing the molecular weight of thiols. The selective hydrogenation of dienes and the molecular weight increase of thiols are preferably carried out on a sulfidation catalyst comprising at least one Group VIII element and optionally at least one Group VIb element, and an oxide support. The Group VIII element is preferably selected from nickel and cobalt, particularly nickel. When a Group VIb element is present, it is preferably selected from molybdenum and tungsten, with molybdenum being very preferred. The oxide support for the selective hydrogenation catalyst is preferably selected from alumina, nickel aluminate, silica, silicon carbide, or mixtures of these oxides. Alumina is preferred, and high-purity alumina is even more preferred. According to a preferred embodiment, the selective hydrogenation catalyst comprises nickel in the form of nickel oxide (NiO) at a content of 1% to 12% by weight and molybdenum in the form of molybdenum oxide (MoO3) at a content of 6% to 18% by weight, with a nickel / molybdenum molar ratio of 0.3 to 2.5, the metal being deposited on a support made of alumina, and the degree of sulfidation of the metal constituting the catalyst being greater than 50%.

[0060] In the optional selective hydrogenation stage, gasoline and catalyst are heated at a temperature of 50°C to 250°C, preferably 80°C to 220°C, and even more preferably 90°C to 200°C, for 0.5 hours. -1 Up to 20h -1 Contact with liquid hourly space velocity (LHSV), where LHSV is measured in liters per liter of catalyst and liters per hour of feed (L / Lh). The pressure is from 0.4 MPa to 5 MPa, preferably from 0.6 to 4 MPa, and even more preferably from 1 to 2 MPa. Optional selective hydrogenation stages are typically performed at 2 to 100 Sm. 3 Hydrogen / m 3 Raw materials, preferably 3 to 30 Sm 3 Hydrogen / m 3 The ratio of H2 to gasoline feedstock is used for the raw materials.

[0061] catalyst

[0062] The catalyst according to the method of the present invention comprises an oxide support, sulfur, and an active phase, said active phase comprising at least one Group VIb metal and at least one Group VIII metal, and said catalyst further comprises a graphite material. It may also comprise phosphorus and / or sulfur and / or organic compounds as described below.

[0063] The oxide support for the catalyst in the method according to the invention is typically selected from porous solids such as alumina, silica, silica-alumina, and titanium oxide or magnesium oxide, which are used alone or as a mixture with alumina or silica-alumina.

[0064] The oxide support advantageously has a total pore volume of 0.1 to 1.5 ml / g, preferably 0.4 to 1.1 ml / g.

[0065] The oxide support has an advantageous thickness of 5 to 400 m 2 ·g -1 Preferred size is 10 to 350m 2 ·g -1 More preferably 40 to 350m 2 ·g -1 Specific surface area.

[0066] It is preferably selected from the group consisting of silica, transition alumina, and silica-alumina; very preferably, the oxide support is substantially composed of at least one transition alumina, that is, it contains at least 51% by weight, preferably at least 60% by weight, very preferably at least 80% by weight, and practically even at least 90% by weight of transition alumina. It preferably consists only of transition alumina. Preferably, the oxide support of the catalyst according to the method of the invention is γ-phase alumina.

[0067] In another preferred embodiment, the oxide present in the support of the catalyst according to the method of the invention is silica-alumina, comprising at least 50% by weight of alumina relative to the total weight of the composite support. The silica content in the support is at most 50% by weight relative to the total weight of the support, typically less than or equal to 45% by weight, preferably less than or equal to 40% by weight.

[0068] Silicon sources are well known to those skilled in the art. For example, silicic acid, silicon dioxide in powder form or in colloidal form (silica sol) or tetraethyl orthosilicate Si(OEt)4 may be mentioned.

[0069] When the catalyst is supported on silica, it contains more than 50% by weight of silica relative to the total weight of the support, and typically it contains only silica.

[0070] According to a particularly preferred alternative, the carrier consists of alumina, silicon dioxide, or a silicon dioxide-alumina mixture.

[0071] The carrier is advantageously provided in the form of beads, extrusions, granules or irregular and non-spherical agglomerates, the specific shape of which can be produced by the crushing stage.

[0072] The active phase of the catalyst comprises at least one Group VIb metal and at least one Group VIII metal. The Group VIb metal present in the active phase of the catalyst is preferably selected from molybdenum and tungsten. The Group VIII metal present in the active phase of the catalyst is preferably selected from cobalt, nickel, and mixtures of these two elements. The active phase of the catalyst is preferably selected from combinations of elements nickel-molybdenum, cobalt-molybdenum, and nickel-cobalt-molybdenum, and very preferably the active phase consists of cobalt and molybdenum.

[0073] The content of Group VIII metals, expressed as oxides of Group VIII metals, is 1% to 10% by weight relative to the total weight of the catalyst, preferably 1.5% to 9% by weight, and more preferably 2% to 8% by weight. When the metal is cobalt or nickel, the metal content is expressed as CoO or NiO, respectively.

[0074] The content of Group VIb metals, expressed as oxides of Group VIb metals, is 5% to 40% by weight, preferably 8% to 35% by weight, and most preferably 10% to 30% 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.

[0075] The molar ratio of Group VIII metals to Group VIb metals in the catalyst is preferably 0.1 to 0.8, more preferably 0.15 to 0.6, and even more preferably 0.15 to 0.45.

[0076] The catalyst of the method according to the invention comprises a carbon and hydrogen-containing graphite material, wherein the graphite material is oxygen-free.

[0077] Carbon and hydrogen-containing graphite materials should be understood as materials obtained by the carbonization of one or more oxygen-free hydrocarbon compounds. Graphite materials can also be coke formed on a catalyst during a pre-hydrogenation treatment process. It should be noted that the term "graphite material" in this application refers to a substance based on hydrocarbons deposited on the surface of a catalyst or oxide support during the use of the catalyst or oxide support, which is highly cyclized and condensed and has an appearance similar to graphite.

[0078] It is important to emphasize that the carbon and hydrogen in graphite materials are not (or are no longer) in the form of organic molecules. However, in addition to graphite materials containing carbon and hydrogen, catalysts can also contain organic compounds (additives) as described below.

[0079] The carbon content, expressed as carbon element, is 5% to 20% by weight relative to the total weight of the catalyst, preferably 7% to 18% by weight, and very preferably 10% to 15% by weight.

[0080] The atomic ratio of hydrogen to carbon is less than 1.4, preferably 0.7 to 1.3, and in a more preferred manner 0.8 to 1.2.

[0081] The carbon content of a catalyst refers to the carbon content of the catalyst without considering the carbon contained in any organic additives that may be included in the catalyst. For this purpose, the carbon content and H / C atomic ratio were determined according to ASTM D5373 after the catalyst was pretreated in a dry air stream at 300°C for 2 hours at a flow rate of 2 L / h / g.

[0082] Carbon content refers to the carbon content of the catalyst at the start of the hydrodesulfurization process. During the process, the carbon content may increase due to coke deposition.

[0083] The catalyst used in the method according to the invention further comprises sulfur.

[0084] The sulfur content in the catalyst, expressed as elemental sulfur, is preferably 1% to 8% by weight relative to the total weight of the catalyst, more preferably 1% to 6% by weight, and very preferably 2% to 5% by weight.

[0085] The sulfur content of a catalyst refers to the total sulfur content of the catalyst introduced during the formation (carbonization) of the graphite material or already contained in the used catalyst, taking into account sulfur contained in organic additives that may be present in the catalyst or sulfur introduced through possible activation (sulfidation). For this purpose, the sulfur content is determined according to the ASTM D5373 method (conventional, i.e., without the catalyst pretreatment performed for measuring carbon content).

[0086] The catalyst according to the method of the present invention may also contain phosphorus as a dopant. A dopant is an added element that does not exhibit any catalytic properties on its own, but increases the catalytic activity of the active phase.

[0087] The phosphorus content in the catalyst is preferably expressed as P2O5, from 0.1% to 20% by weight relative to the total weight of the catalyst, more preferably expressed as P2O5, from 0.2% to 15% by weight, and very preferably expressed as P2O5, from 0.3% to 6% by weight.

[0088] The catalyst may also contain at least one organic compound containing oxygen and / or nitrogen and / or sulfur prior to sulfidation. Such additives will be described later.

[0089] When organic compounds are present, the total content of one or more oxygen- and / or nitrogen- and / or sulfur-containing organic compounds present in the catalyst is typically 1% to 30% by weight relative to the total weight of the catalyst, preferably 1.5% to 25% by weight, more preferably 2% to 20% by weight.

[0090] The catalyst according to the method of the invention advantageously has a total pore volume of 0.15 ml / g or greater, preferably 0.18 ml / g or greater, and particularly preferably 0.2 to 0.5 ml / g.

[0091] The catalyst according to the method of the present invention is characterized by a specific surface area of ​​20 to 200 m². 2 / g, preferably 30 to 180m 2 / g, preferably 40 to 160m 2 / g, with a highly preferred concentration of 50 to 150 mg 2 / g.

[0092] The catalyst according to the method of the invention is advantageously in the form of particles having an average diameter of 0.5 to 10 mm. The particles can have all forms known to those skilled in the art, such as beads (preferably having a diameter of 1 to 6 mm), extrusions, flakes, or hollow cylinders. Preferably, the catalyst (and the support for preparing the catalyst) is in the form of an extrusion having an average diameter of 0.5 to 10 mm, preferably 0.8 to 3.2 mm, and an average length of 0.5 to 20 mm, or in the form of beads having an average diameter of 0.5 to 10 mm, preferably 1.4 to 4 mm. The term "average diameter" for extrusions should be understood to refer to the average diameter of the circumscribed circle in the cross-section of these extrusions. The catalyst can advantageously be in the form of cylindrical extrusions, multi-lobed extrusions, trilobed extrusions, or tetralobed extrusions. Preferably, its shape will be trilobed or tetralobed. The shape of the lobes can be adjusted according to all known methods in the prior art.

[0093] Catalyst preparation methods

[0094] The catalyst according to the method of the present invention can be prepared according to any method of catalyst preparation known to those skilled in the art.

[0095] The catalyst according to the method of the present invention can be prepared according to a preparation method including the following stages:

[0096] a) Contacting at least one hydrocarbon and at least one sulfur-containing compound with the oxide support such that the carbon- and hydrogen-containing graphite material can be formed on the oxide support.

[0097] b) Then, the compound containing a Group VIb metal and the compound containing a Group VIII metal, as well as optionally phosphorus and / or at least one oxygen- and / or nitrogen- and / or sulfur-containing organic compound, are contacted with the oxide support containing the graphite material.

[0098] To obtain catalytic precursors,

[0099] c) The catalytic precursor is dried at a temperature below 200°C without subsequent calcination to obtain a dry catalyst.

[0100] d) Optionally, the dried catalyst is activated in the presence of a sulfiding agent.

[0101] Step a) of contacting at least one hydrocarbon and at least one sulfur-containing compound with the oxide support to form the graphite material can be carried out in various alternative forms. The preparation of the oxide support containing the graphite material can be achieved by contacting the oxide support with at least one hydrocarbon selected from olefins, dienes, monoaromatics, and polyaromatics and a sulfur-containing compound, typically in the presence of a gas stream containing nitrogen or hydrogen, thereby proceeding by carbonization of the oxide support.

[0102] Hydrocarbons should be understood as compounds containing carbon and hydrogen atoms, and preferably composed of carbon and hydrogen atoms. Specifically, the hydrocarbons do not contain oxygen atoms.

[0103] According to the first alternative carbonization form, the graphite material is formed by chemical vapor deposition of olefins and / or diene compounds.

[0104] According to this first alternative form, the graphite material used in the method according to the invention is prepared by a method comprising the following steps: contacting a gas containing nitrogen or hydrogen, a sulfur-containing compound, and one or more olefins and / or dienes with an oxide support at a temperature of 500 to 900°C and a pressure of 0.05 to 10 MPa for a period of 0.25 to 12 hours. The sulfur-containing compound may be H₂S or a compound capable of decomposing to produce H₂S, such as dimethyl disulfide. The olefins and / or dienes are molecules containing one or more degrees of unsaturation, advantageously of the olefin (ethylene, propylene, butene) or diene (isoprene, butadiene) type.

[0105] According to a second alternative carbonization form, the graphite material is formed by reacting one or more hydrocarbons selected from monoaromatic or polyaromatic compounds. According to this second alternative form, the graphite material used in the method according to the invention is prepared by a method comprising the following steps: contacting a gas containing nitrogen or hydrogen, a sulfur-containing compound, and one or more hydrocarbons containing at least one aromatic nucleus with an oxide support at a temperature of 300 to 600°C and a pressure of 0.05 to 10 MPa for a period of 0.25 to 12 hours. The sulfur-containing compound may be H₂S or a compound capable of decomposing to produce H₂S, such as dimethyl disulfide. The hydrocarbon is a molecule containing one or more aromatic nuclei, advantageously of a monoaromatic type (benzene, toluene, o-xylene, m-xylene, p-xylene, tetrahydronaphthalene) or a diaromatic type.

[0106] According to the third alternative carbonization form, the graphite material is formed by reacting at least 90% of the compound with a hydrocarbon fraction having a boiling point of 250°C to 400°C at atmospheric pressure.

[0107] This fraction typically contains a mixture of several monoaromatic or polyaromatic hydrocarbons, olefins, and dienes. According to this third alternative form, the graphite material used in the method according to the invention is prepared by a process comprising the following steps: contacting a hydrocarbon fraction containing a gas of nitrogen or hydrogen, at least one sulfur-containing compound, and at least 90% of the compound at atmospheric pressure with an oxide support at a temperature of 300 to 600°C and a pressure of 0.05 to 15 MPa for a period of 0.25 to 12 hours. The sulfur compound may be H₂S or a compound capable of decomposing to produce H₂S, such as dimethyl disulfide, or any other sulfur-containing compound, such as thiophene, alkylthiophene, benzothiophene, alkylbenzothiophene, dibenzothiophene, or alkyldibenzothiophene. The fraction does not contain oxygen-containing compounds.

[0108] According to stage b) of the method for preparing the catalyst used according to the method of the invention, a compound containing a group VIb metal and a compound containing a group VIII metal, and optionally phosphorus and / or at least one oxygen- and / or nitrogen- and / or sulfur-containing organic compound are contacted with the oxide support containing the graphite material.

[0109] The contacting of at least one compound containing a Group VIb metal and at least one compound containing a Group VIII metal with the oxide support containing the graphite material can advantageously be carried out by any technique known to those skilled in the art, such as ion exchange, dry impregnation, over-impregnation, vapor deposition, etc. The contacting operation can be performed in one stage or several consecutive stages. According to a preferred form, the contacting stage(s) is carried out by an impregnation method well known to those skilled in the art, described as a “dry” method, by contacting an impregnation solution containing a compound containing a Group VIII metal and a compound containing a Group VIb metal with the oxide support containing the graphite material.

[0110] Contact operations advantageously involve the precursor of the metal.

[0111] For example, in molybdenum sources, oxides and hydroxides, molybdic acid and its salts, especially ammonium salts, such as ammonium molybdate or ammonium heptamolybdate, phosphomolybdic acid (H3PMo) can be used. 12 O 40 ) and its salts, and optionally silicomolybdic acid (H4SiMo) 12 O 40 Molybdenum source can also be 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.

[0112] The tungsten precursors that can be used are also well known to those skilled in the art. For example, in the tungsten source, 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 tungsten source can also be any heteropoly compound, such as Keggin type, vacant Keggin type, substituted Keggin type, or Dawson type. Oxides and ammonium salts, such as ammonium metatungstate, or heteropoly anions of Keggin type, vacant Keggin type, or substituted Keggin type, are preferred.

[0113] 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.

[0114] The nickel precursors that can be used are advantageously selected from, for example, oxides, hydroxides, basic carbonates, carbonates and nitrates.

[0115] Any impregnation solution described in this invention may contain any polar proton solvent known to those skilled in the art. Polar proton solvents, such as those selected from methanol, ethanol, and water, are preferred. Preferably, the impregnation solution contains water-ethanol or a water-methanol mixture as a solvent to facilitate the impregnation of compounds containing Group VIb metals and compounds containing Group VIII metals (and optionally phosphorus and / or organic compounds described below) onto an oxide support containing graphite material, thus being partially hydrophobic. Preferably, the solvent used in the impregnation solution consists of water-ethanol or a water-methanol mixture.

[0116] According to another alternative form, contact stage b) may also include contacting an oxide support containing graphite material with an impregnation solution containing phosphorus in addition to compounds containing group VIb metals and compounds containing group VIII metals.

[0117] The molar ratio of phosphorus to group VIb elements in the catalyst is greater than or equal to 0.05, preferably greater than or equal to 0.07, preferably 0.08 to 1, preferably 0.1 to 0.9, and very preferably 0.15 to 0.6.

[0118] The preferred phosphorus precursor is orthophosphoric acid (H3PO4), but its salts and esters, such as ammonium phosphate, are also suitable. Phosphorus can also be introduced simultaneously with one or more Group VIb elements in the form of Keggin, absent Keggin, substituted Keggin, or Strandberg heteropolyanions.

[0119] According to another alternative form, contact stage b) may further include contacting an oxide support containing graphite material with an impregnation solution containing, in addition to compounds containing Group VIb metals, compounds containing Group VIII metals, and optionally phosphorus, an organic compound containing oxygen and / or nitrogen and / or sulfur. The role of the additive or organic compound is to improve catalytic activity compared to a catalyst without additives. Preferably, the organic compound is impregnated onto the catalyst after being dissolved in an aqueous or non-aqueous solution.

[0120] In this case, the molar ratio of the added organic compound to the group VIb metal in the solution is 0.01 to 5 mol / mol, preferably 0.05 to 3 mol / mol, more preferably 0.05 to 2 mol / mol, and very preferably 0.1 to 1.5 mol / mol.

[0121] When several organic compounds are present, various molar ratios apply to each of the organic compounds present.

[0122] Typically, organic compounds are selected from compounds containing one or more chemical functional groups selected from carboxyl, alcohol, thiol, thioether, sulfone, sulfoxide, ether, aldehyde, ketone, ester, carbonate, amine, nitrile, imide, oxime, urea and amide, or compounds containing a furan ring or sugar.

[0123] Oxygen-containing organic compounds are understood herein to refer to compounds that do not contain another heteroatom. For example, an oxygen-containing organic compound may be selected from one or more of the following: ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol (molecular weight 200 to 1500 g / mol), propylene glycol, 2-butoxyethanol, 2-(2-butoxyethoxy)ethanol, 2-(2-methoxyethoxy)ethanol, triethylene glycol dimethyl ether, glycerol, acetophenone, 2,4-pentanedione, pentanone, acetic acid, oxalic acid, maleic acid, malic acid, malonic acid, oxalic acid, gluconic acid, tartaric acid, citric acid, γ-ketone. Valeric acid, di(C1-C4) succinate and more particularly dimethyl succinate, methyl acetoacetate, ethyl acetoacetate, 2-methoxyethyl 3-oxobutyrate, 2-methacryloyloxyethyl 3-oxobutyrate, dibenzofuran, crown ether, phthalic acid, glucose, fructose, sucrose, sorbitol, xylitol, γ-valerolactone, 2-acetylbutyrolactone, propylene carbonate, 2-furfural (also known as furfural), 5-hydroxymethylfurfural (also known as 5-(hydroxymethyl)-2-furfural or 5 -HMF), 2-acetylfuran, 5-methyl-2-furfural, methyl 2-furfuryl acid, furfuryl alcohol (also known as furanol), furfuryl acetate, ascorbic acid, butyl lactate, ethyl lactate, butyryl butyl lactate, ethyl 3-hydroxybutyrate, ethyl 3-ethoxypropionate, methyl 3-methoxypropionate, 2-ethoxyethyl acetate, 2-butoxyethyl acetate, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,5-hexanediol Diol, 3-ethyl-1,5-pentanediol, 2,4-diethyl-1,5-pentanediol, 5-methyl-2(3H)-furanone, butyl glycolate, ethyl 4-oxopentanoate, diethyl maleate, dimethyl maleate, dimethyl fumarate, diethyl fumarate, dimethyl adipate, dimethyl 3-oxopentanoate, dimethyl tartrate, diethyl tartrate, diisopropyl tartrate, di-tert-butyl tartrate, dimethyl malate, diethyl malate, diisopropyl malate, and dibutyl malate.

[0124] Nitrogen-containing organic compounds can be selected from one or more of the following: compounds containing one or more chemical functional groups selected from amine or nitrile functional groups. Nitrogen-containing organic compounds are understood herein to mean compounds that do not contain other heteroatoms. For example, nitrogen-containing organic compounds can be selected from one or more of the following: ethylenediamine, diethylenetriamine, hexamethylenediamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, acetonitrile, octylamine, guanidine, and carbazole.

[0125] Oxygen- and nitrogen-containing organic compounds can be selected from one or more of the following: compounds containing one or more chemical functional groups selected from carboxylic acids, alcohols, ethers, aldehydes, ketones, esters, carbonates, amines, nitriles, imides, amides, ureas, or oxime functional groups. Oxygen- and nitrogen-containing organic compounds are understood herein to mean compounds that do not contain other heteroatoms. For example, oxygen- and nitrogen-containing organic compounds can be selected from one or more of the following: 1,2-cyclohexanediaminetetraacetic acid, monoethanolamine (MEA), 1-methyl-2-pyrrolidone, dimethylformamide, ethylenediaminetetraacetic acid (EDTA), alanine, glycine, nitrotriacetic acid (NTA), N-(2-hydroxyethyl)ethylenediamine-N,N′,N′-triacetic acid (HEDTA), diethylenetriaminepentaacetic acid (DTPA), tetramethylurea, glutamic acid, dimethylglyoxime. N,N-bis(2-hydroxyethyl)glycine, tris(hydroxymethyl)methylglycine, 2-methoxyethyl cyanoacetate, 1-ethyl-2-pyrrolidone, 1-vinyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidineone, 1-(2-hydroxyethyl)-2-pyrrolidone, 1-(2-hydroxyethyl)-2,5-pyrrolidone, 1-methyl-2-piperidinone, 1-acetyl-2-azacycloheptanone, 1-vinyl-2-azacycloheptanone, and 4-aminobutyric acid.

[0126] Sulfur-containing organic compounds can be selected from one or more of the following: compounds containing one or more chemical functional groups selected from thiols, thioethers, sulfones, or sulfoxides. For example, sulfur-containing organic compounds can be selected from one or more of the following: mercaptoacetic acid, 2,2′-thiodiethanol, 2-hydroxy-4-methylthiobutyric acid, sulfone derivatives or sulfoxide derivatives of benzothiophene, ethyl 2-mercaptopropionate, methyl 3-(methylthio)propionate, and ethyl 3-(methylthio)propionate.

[0127] Preferably, the organic compound contains oxygen; preferably, it is selected from γ-valerolactone, 2-acetylbutyrolactone, triethylene glycol, diethylene glycol, ethylene glycol, ethylenediaminetetraacetic acid (EDTA), maleic acid, malonic acid, citric acid, acetic acid, oxalic acid, gluconic acid, glucose, fructose, sucrose, sorbitol, xylitol, γ-ketovalerate, di(C1-C4 alkyl) succinate and more particularly dimethyl succinate, dimethylformamide, 1-methyl-2-pyrrolidone, propylene carbonate, 2-methoxyethyl 3-oxobutyrate, N,N-bis(2-hydroxyethyl)glycine, tris(hydroxymethyl)methylglycine, 2-furfural (also known as furfural), 5-hydroxymethylfurfural (also known as 5-(hydroxymethyl)-2-furfural or 5-HMF), 2-acetylfuran, 5- Methyl-2-furfural, ascorbic acid, butyl lactate, ethyl lactate, butyryl butyl lactate, ethyl 3-hydroxybutyrate, ethyl 3-ethoxypropionate, 2-ethoxyethyl acetate, 2-butoxyethyl acetate, 2-hydroxyethyl acrylate, 1-vinyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolium ketone, 1,5-pentanediol, 1-(2-hydroxyethyl)-2-pyrrolidone, 1-(2-hydroxyethyl)-2,5-pyrrolidone, 5-methyl-2(3H)-furanone, 1-methyl-2-piperidinone, 4-aminobutyric acid, butyl glycolate, ethyl 2-mercaptopropionate, ethyl 4-oxopentanoate, diethyl maleate, dimethyl maleate, dimethyl fumarate, diethyl fumarate, dimethyl adipate, and dimethyl 3-oxopentanoate.

[0128] The impregnation stage includes several embodiments. They are characterized in particular by the timing of the introduction of an organic compound (when present), which can occur simultaneously with metal impregnation (co-impregnation), after impregnation (post-impregnation), or before impregnation (pre-impregnation). Furthermore, these embodiments can be combined.

[0129] Advantageously, the impregnated carrier is aged after each impregnation stage. Aging allows the impregnation solution to be uniformly dispersed within the carrier.

[0130] Any curing stage described in this invention is advantageously carried out at atmospheric pressure, in a water-saturated atmosphere, at a temperature of 17°C to 50°C, and preferably at ambient temperature. Typically, a curing time of ten minutes to forty-eight hours, preferably thirty minutes to six hours, is sufficient.

[0131] Following step b), a catalytic precursor is thus obtained, comprising: an oxide support containing graphite material, an active phase containing at least one Group VIb metal and at least one Group VIII metal, sulfur, and optionally phosphorus and / or an oxygen- and / or nitrogen- and / or sulfur-containing organic compound.

[0132] According to stage c) of the method for preparing the catalyst used according to the method of the invention, the catalyst precursor is dried at a temperature below 200°C, advantageously 50°C to 180°C, preferably 70°C to 150°C, and most preferably 75°C to 130°C, without subsequent calcination, to obtain a dried catalyst.

[0133] The drying stage is preferably carried out under an inert atmosphere, and is usually carried out under a nitrogen atmosphere.

[0134] The drying stage can be carried out using any technique known to those skilled in the art. It is advantageously carried out at atmospheric pressure or under reduced pressure. Preferably, the stage is carried out at atmospheric pressure. It is advantageously carried out in a cross-flow bed using any thermal inert gas. Preferably, when drying is carried out in a fixed bed, the gas used is argon or nitrogen. Very preferably, drying is carried out in a cross-flow bed in the presence of nitrogen. Preferably, the duration of the drying stage is from 5 minutes to 15 hours, more preferably from 30 minutes to 12 hours.

[0135] According to an alternative form, and advantageously when organic compounds are present, drying is carried out to preferably retain at least 30% by weight of the organic compounds introduced during the impregnation stage; preferably, this amount is greater than 50% by weight, and even more preferably greater than 70% by weight, based on the carbon retained on the catalyst.

[0136] The carbon content derived from organic compounds can be determined by comparing the carbon content measured according to ASTM D5373 with and without pretreatment of the catalyst by drying it in a dry air stream at 300°C at a flow rate of 2 L / h / g for 2 hours. This is because carbon in graphite materials exhibits a significantly higher decomposition temperature (typically around 400 to 450°C) than that of organic compounds (typically around 100 to 200°C).

[0137] It is important to emphasize that in the catalyst preparation process, the catalyst does not undergo calcination to preserve the graphite material, and when organic compounds are present, at least partially, the organic compounds in the catalyst are preserved. Calcination is understood here as heat treatment in a gas containing air or oxygen at a temperature greater than or equal to 200°C.

[0138] At the end of the drying stage, the dried catalyst is then obtained, which will undergo an optional activation (sulfidation) stage in order to be subsequently used in a gasoline hydrodesulfurization process.

[0139] Therefore, according to stage d) of the method for preparing the catalyst used according to the method of the invention, the dried catalyst is optionally activated in the presence of a sulfiding agent.

[0140] Sulfidation is preferably carried out in a sulfur-containing reducing medium, that is, in the presence of H2S and hydrogen. Sulfidation is performed by injecting a stream containing H2S and hydrogen, or a sulfur-containing compound capable of decomposing to produce H2S in the presence of a catalyst and hydrogen, onto the catalyst. Polysulfides, such as dimethyl disulfide (DMDS), are commonly used H2S precursors for sulfide catalysts. The temperature is adjusted to allow H2S to react with the dry catalyst to form metal sulfides, such as MoS2 and Co9S8. This sulfidation can be carried out at temperatures of 200 to 600°C and more preferably 300 to 500°C in situ or ex-situ (inside or outside the reactor) in a reactor according to the method of the invention.

[0141] For a metal to be active, it must be substantially sulfided. An element is considered substantially sulfided when the molar ratio of sulfur (S) present on the catalyst to the element is at least 50% of the theoretical molar ratio corresponding to complete sulfidation of the element under consideration. The total degree of sulfidation is defined by the following equation:

[0142] (S / Element) 催化剂 >= 0.5 × (S / element) 理论

[0143] in:

[0144] (S / Element) 催化剂 The molar ratio of sulfur (S) present on the catalyst to the element

[0145] (S / Element) 理论 This corresponds to the molar ratio of sulfur to the element in the sulfide produced by the complete sulfidation of the element.

[0146] The theoretical molar ratio varies depending on the elements considered:

[0147] -(S / Co) 理论 =8 / 9

[0148] -(S / Ni) 理论 =1 / 1

[0149] -(S / Mo) 理论 =2 / 1

[0150] -(S / W) 理论 =2 / 1

[0151] When a catalyst contains several metals, the molar ratio of sulfur present on the catalyst to the combined elements must also be at least 50% of the theoretical molar ratio corresponding to the complete sulfidation of each element to produce sulfides, calculated in a manner proportional to the relative molar fraction of each element.

[0152] For example, for catalysts containing molybdenum and nickel with mole fractions of 0.7 and 0.3 respectively, the minimum molar ratio (S / Mo+Ni) is given by the following relationship:

[0153] (S / Mo+Ni) 催化剂 =0.5×[(0.7×2)+(0.3×1)]

[0154] Very preferably, the degree of sulfidation of the metal is greater than 70%.

[0155] According to another alternative form of the invention, the catalyst in the method according to the invention does not undergo a sulfidation stage before being injected into the feedstock; that is, the catalyst does not come into contact with a sulfiding agent. In this case, the catalyst is activated (sulfided) by the sulfur contained in the feedstock to be desulfurized.

[0156] According to any other alternative form, the catalyst in the method according to the invention can be a catalyst that is at least partially used. A catalyst that is at least partially used should be understood to refer to catalyst discharged from a hydrotreating process. The catalyst that is at least partially used can be produced by the hydrotreating of any petroleum fraction (e.g., naphtha, kerosene, gas oil, vacuum distillate, or residue fraction). Hydrotreating should be understood to specifically include reactions comprising hydrodesulfurization (HDS), hydronitrogenation (HDN), and aromatics hydrogenation (HDA). It can also be produced by the hydrotreating of biomass or bio-oil. Preferably, the catalyst that is at least partially used is produced by a hydrodesulfurization process of a sulfur-containing olefinic gasoline fraction carried out under the conditions described below.

[0157] Advantageously, at least partially used catalyst does not undergo regeneration; that is, heat treatment at temperatures above 200°C in a gas containing air or oxygen typically allows for the combustion of most of the coke formed during hydrotreating processes in which the catalyst was previously used. Before being used in the gasoline hydrodesulfurization method of the present invention, it can undergo a deoiling stage. The deoiling stage typically involves contacting at least partially used catalyst with an inert gas stream (i.e., substantially oxygen-free), such as in a nitrogen atmosphere, at a temperature of 300°C to 400°C, preferably 300°C to 350°C, for 3 to 7 hours. The inert gas flow rate is 5 to 150 sl per unit volume of catalyst. -1 .h -1 In an alternative form, the deoiling stage can be carried out with light hydrocarbons, via steam treatment or any other similar method.

[0158] The deoiling stage allows for the removal of soluble hydrocarbons and thus releases at least some of the pores of the spent catalyst necessary for hydrodesulfurization.

[0159] The at least partially used catalyst comprises the oxide support, sulfur, an active phase comprising at least one Group VIb metal and at least one Group VIII metal, optionally phosphorus, and the carbon and hydrogen-containing graphite material in the form of coke, the graphite material being oxygen-free.

[0160] The metal, sulfur, carbon, and phosphorus contents of at least partially used catalysts are as described above. They are determined using the same method as described above.

[0161] Optionally, at least partially used catalysts may also exhibit low levels of contaminants, such as silicon, arsenic, or chlorine, generated from the treated feedstock.

[0162] Preferably, the silicon content (besides silicon that may be present on the catalyst) is less than 2% by weight relative to the total weight of the catalyst that has been at least partially used, and very preferably less than 1% by weight.

[0163] Preferably, the arsenic content is less than 2000 ppm by weight relative to the total weight of at least partially used catalyst, and most preferably less than 500 ppm by weight.

[0164] Preferably, the chlorine content is less than 2000 ppm by weight relative to the total weight of at least partially used catalyst, and most preferably less than 500 ppm by weight. Example

[0165] Example 1 - Preparation of Catalyst A (according to the present invention)

[0166] 50cm 3 BET has a specific surface area of ​​230m². 2 An alumina support, provided in "extrusion" form, with a pore volume (measured by mercury porosimetry) of 0.78 ml / g and an average pore diameter (defined as the median diameter of the volume measured by mercury porosimetry) of 11.5 nm, was loaded into a crossflow bed reactor. The support was carbonized under the following conditions using a feedstock consisting of 20 wt% toluene, 5.9 wt% dimethyl disulfide, and 74.1 wt% hexane: T = 350 °C, HSV = 4.5 h. -1 P tot =60 bar (6 MPa), H2 / raw material volume ratio = 150Sl / l.

[0167] The water absorption volume of the carbonization support is 0.5 ml / g. Then cobalt, molybdenum, and phosphorus are added. Molybdenum oxide (2.2 g, MoO3 > 99.5%, Merck) is added at 90 °C. TM ), cobalt hydroxide (0.57 g, 95% Co(OH)2, Merck) TM ) and 85% by weight of hydrated phosphoric acid (0.46 g, Merck) TMThe impregnation solution was prepared by dissolving the carbonized support in 4.7 ml of distilled water. After dry impregnation of 10 g of carbonized support, the extrudate was aged at ambient temperature for 24 h in a water-saturated atmosphere, and then dried at 90 °C for 16 h. The resulting dried catalyst is denoted as A. Subsequently, the final metallic composition of the catalyst (expressed as oxides and relative to the weight of the dried catalyst) is as follows: MoO3 = 17.1 ± 0.2 wt%, CoO = 3.4 ± 0.1 wt%, P2O5 = 2.2 ± 0.1 wt%. The catalyst exhibits 4.3 wt% S relative to the weight of the catalyst as analyzed by CHNS according to ASTM D5373, and 10.7 wt% C relative to the weight of the catalyst, H / C ratio = 1.05, after pretreatment of the catalyst in a dry air stream at 300 °C at a flow rate of 2 l / h / g for 2 h, according to CHNS analysis of ASTM D5373.

[0168] Example 2 - Preparation of Catalyst B (not based on the present invention)

[0169] 50cm 3 The same support as described in Example 1 was loaded into a crossflow bed reactor. Carbonization of the support was carried out under the following conditions using a feedstock consisting of 25 wt% toluene, 5.9 wt% dimethyl disulfide, and 69.1 wt% hexane: T = 400 °C, HSV = 4.5 h. -1 P tot =60 bar (6 MPa), H2 / raw material volume ratio = 150Sl / l.

[0170] The water absorption volume of the carbonized support was 0.51 ml / g. Cobalt, molybdenum, and phosphorus were then added. An impregnation solution was prepared by dissolving molybdenum oxide (2.2 g), cobalt hydroxide (0.57 g), and 85% wt% hydrated phosphoric acid (0.46 g) in 4.8 ml of distilled water at 90 °C. After dry impregnation of 10 g of the carbonized support, the extrudates were aged at ambient temperature in a water-saturated atmosphere for 24 h, and then dried at 90 °C for 16 h. The resulting dried catalyst is denoted as B. Subsequently, the final metallic composition of the catalyst (expressed as oxides relative to the weight of the dried catalyst) is as follows: MoO3 = 17.1 ± 0.2 wt%, CoO = 3.4 ± 0.1 wt%, P2O5 = 2.2 ± 0.1 wt%. The catalyst exhibits 4.2 wt% S relative to the catalyst weight as analyzed by CHNS analysis according to ASTM D5373, and 10.4 wt% C relative to the catalyst weight after pretreatment in a dry air stream at 300°C at a flow rate of 2 l / h / g for 2 h, with an H / C ratio of 1.51 as analyzed by CHNS analysis according to ASTM D5373.

[0171] Example 3 - Preparation of Catalyst C (not based on the present invention)

[0172] 50cm 3 The same support as described in Example 1 was loaded into a crossflow bed reactor. Carbonization of the support was carried out under the following conditions using a feedstock consisting of 20 wt% cyclohexene, 5.9 wt% dimethyl disulfide, and 74.1 wt% hexane: T = 350 °C, HSV = 4.5 h. -1 P tot =60 bar (6 MPa), H2 / raw material volume ratio = 150Sl / l.

[0173] The water absorption volume of the carbonized support was 0.77 ml / g. Cobalt, molybdenum, and phosphorus were then added. An impregnation solution was prepared by dissolving molybdenum oxide (2.2 g), cobalt hydroxide (0.57 g), and 85% wt% hydrated phosphoric acid (0.46 g) in 7.3 ml of distilled water at 90 °C. After dry impregnation of 10 g of the carbonized support, the extrudates were aged at ambient temperature in a water-saturated atmosphere for 24 h, and then dried at 90 °C for 16 h. The resulting dried catalyst is denoted as C. Subsequently, the final metallic composition of the catalyst (expressed as oxides relative to the weight of the dried catalyst) is as follows: MoO3 = 17.1 ± 0.2 wt%, CoO = 3.4 ± 0.1 wt%, P2O5 = 2.2 ± 0.1 wt%. The catalyst exhibits 0.9 wt% S relative to the catalyst weight as analyzed by CHNS analysis according to ASTM D5373, and 1.4 wt% C relative to the catalyst weight after pretreatment in a dry air stream at 300°C at a flow rate of 2 l / h / g for 2 h, with an H / C ratio of 1.12 as analyzed by CHNS analysis according to ASTM D5373.

[0174] Example 4 - Preparation of Catalyst D (not based on the present invention)

[0175] 50cm 3 The same support as described in Example 1 was loaded into a crossflow bed reactor. Carbonization of the support was carried out under the following conditions using a feedstock consisting of 40 wt% toluene, 5.9 wt% dimethyl disulfide, and 54.1 wt% hexane: T = 350 °C, HSV = 6 h. -1 P tot =60 bar (6 MPa), H2 / raw material volume ratio = 50Sl / l.

[0176] The water absorption volume of the carbonized support was 0.40 ml / g. Cobalt, molybdenum, and phosphorus were then added. An impregnation solution was prepared by dissolving molybdenum oxide (2.2 g), cobalt hydroxide (0.57 g), and 85% wt% hydrated phosphoric acid (0.46 g) in 3.7 ml of distilled water at 90 °C. After dry impregnation of 10 g of the carbonized support, the extrudates were aged at ambient temperature in a water-saturated atmosphere for 24 h, and then dried at 90 °C for 16 h. The resulting dried catalyst is denoted as D. Subsequently, the final metallic composition of the catalyst (expressed as oxides relative to the weight of the dried catalyst) is as follows: MoO3 = 17.1 ± 0.2 wt%, CoO = 3.4 ± 0.1 wt%, P2O5 = 2.2 ± 0.1 wt%. The catalyst exhibits 1.6 wt% S relative to the catalyst weight as analyzed by CHNS analysis according to ASTM D5373, and 20.9 wt% C relative to the catalyst weight after pretreatment in a dry air stream at 300°C for 2 hours at a flow rate of 2 l / h / g, with an H / C ratio of 1.03 as analyzed by CHNS analysis according to ASTM D5373.

[0177] Example 5 - Preparation of Catalyst E (not based on the present invention)

[0178] In an autoclave, 2 g of phenol and 15 g of the same support as described in Example 1 were mixed with 50 ml of water and 50 ml of ethanol. The system was sealed and then heated to 200 °C with a gradient of 8 °C / min. This temperature was maintained for 10 hours, and the solid was filtered off. After washing with distilled water, the solid was dried in an oven at 100 °C for 10 hours, and then pyrolyzed in a tube furnace as a crossflow bed at 300 °C for 1 hour under a nitrogen flow of 10 ml / min / g with a temperature gradient of 6 °C / min. The sample was then recovered, and the process was repeated five times consecutively to obtain the mixed support.

[0179] The water absorption volume of the carbonized support was 0.7 ml / g. Cobalt, molybdenum, and phosphorus were then added. An impregnation solution was prepared by dissolving molybdenum oxide (2.2 g), cobalt hydroxide (0.57 g), and 85% wt% hydrated phosphoric acid (0.46 g) in 6.7 ml of distilled water at 90 °C. After dry impregnation of 10 g of the carbonized support, the extrudates were aged at ambient temperature in a water-saturated atmosphere for 24 h, and then dried at 90 °C for 16 h. The resulting dried catalyst is denoted as E. Subsequently, the final metallic composition of the catalyst (expressed as oxides relative to the weight of the dried catalyst) is as follows: MoO3 = 17.1 ± 0.2 wt%, CoO = 3.4 ± 0.1 wt%, P2O5 = 2.2 ± 0.1 wt%. The catalyst exhibits 1.0 wt% O relative to the catalyst weight as analyzed by CHNS analysis according to ASTM D5373, and 10.5 wt% C, H / C ratio = 1.06 relative to the catalyst weight after pretreatment of the catalyst in a dry air stream at 300°C for 2 hours at a flow rate of 2 l / h / g, as analyzed by CHNS analysis according to ASTM D5373.

[0180] Example 6 - Evaluation of the catalytic performance of catalysts A, B, C, D and E

[0181] 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.

[0182] Hydrodesulfurization (HDS) was performed in a fixed crossflow reactor at a total pressure of 1.5 MPa, at 210 °C, and at HSV = 6 h. -1 (HSV = feed volume flow rate / catalyst volume) and an H2 / feed volume ratio of 300 Sl / l were used, with 4 ml of catalyst present. Prior to the HDS reaction, the catalyst was in-situ sulfided for 2 hours at atmospheric pressure in a hydrogen stream containing 15 mol% H2S at 350 °C.

[0183] Each catalyst was placed sequentially into 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.

[0184] The catalytic performance of the catalysts was evaluated in terms of catalytic activity and selectivity. Hydrodesulfurization (HDS) activity was represented by the HDS rate constant (kHDS) of 3-methylthiophene, normalized by the introduced catalyst volume, and presumed first-order kinetics with respect to sulfur-containing compounds. Olefin hydrogenation activity (HydO) was represented by the hydrogenation rate constant of 2,3-dimethylbut-2-ene, normalized by the introduced catalyst volume, and presumed first-order kinetics with respect to olefins.

[0185] 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 value is normalized using catalyst A as a reference (relative HDS activity and relative selectivity equal to 100). Therefore, the performance quality is relative to both HDS activity and relative selectivity.

[0186] Table 1

[0187]

[0188] Among the four catalysts B, C, D and E, with catalyst A as a reference, only catalyst A prepared according to the present invention maintains both hydrodesulfurization activity and improves olefin hydrogenation selectivity.

[0189] In the case of hydrodesulfurization methods for olefin-containing gasoline, this improvement in catalyst selectivity is particularly advantageous, for which the aim is to limit as much as possible the loss of octane number as possible due to olefin hydrogenation.

Claims

1. A method for hydrodesulfurizing a gasoline fraction containing sulfur compounds and olefins, wherein the gasoline fraction, hydrogen, and a catalyst are contacted, the method being carried out at a temperature of 200°C to 400°C, a total pressure of 1 to 3 MPa, and for 1 to 10 h. -1 The experiment was conducted at a space velocity of 100 to 1200 Sl / l hydrogen / gasoline feedstock volume ratio, where space velocity is defined as the volumetric flow rate of the feedstock relative to the volume of the catalyst. The catalyst comprises an oxide support, sulfur, and an active phase, wherein the active phase comprises at least one Group VIb metal and at least one Group VIII metal. The catalyst also comprises a carbon- and hydrogen-containing graphite material, with a carbon content of 5% to 20% by weight relative to the weight of the catalyst, an H / C atomic ratio of 0.8 to 1.2, and the graphite material being oxygen-free.

2. The method as claimed in the preceding claims, wherein the carbon content, expressed in terms of carbon elements, is 10% to 15% by weight relative to the weight of the catalyst.

3. The method as described in any of the preceding claims, wherein the sulfur content, expressed as elemental sulfur, is from 1% to 8% by weight relative to the weight of the catalyst.

4. The method of claim 1 or 2, wherein the catalyst has a group VIb metal content of 5% to 40% by weight relative to the total weight of the catalyst, expressed as group VIb metal oxides, and a group VIII metal content of 1% to 10% by weight relative to the total weight of the catalyst, expressed as group VIII metal oxides.

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

8.

6. The method of claim 1 or 2, wherein the specific surface area of ​​the catalyst is 20 to 200 m². 2 / g.

7. The method of claim 1 or 2, wherein the catalyst further comprises phosphorus, expressed as P2O5, in an amount of 0.1% to 20% by weight relative to the total weight of the catalyst.

8. The method of claim 1 or 2, wherein the catalyst further comprises an organic compound containing oxygen and / or nitrogen and / or sulfur.

9. The method of claim 8, wherein the organic compound is selected from compounds comprising one or more chemical functional groups selected from carboxyl, alcohol, thiol, thioether, sulfone, sulfoxide, ether, aldehyde, ketone, ester, carbonate, amine, nitrile, imide, oxime, urea or amide functional groups, or compounds comprising furan ring or sugar.

10. The method of claim 9, wherein the organic compound is selected from γ-valerolactone, 2-acetylbutyrolactone, triethylene glycol, diethylene glycol, ethylene glycol, ethylenediaminetetraacetic acid, maleic acid, malonic acid, citric acid, acetic acid, oxalic acid, gluconic acid, glucose, fructose, sucrose, sorbitol, xylitol, γ-ketovalerate, di(C1-C4) succinate, dimethylformamide, 1-methyl-2-pyrrolidone, propylene carbonate, 2-methoxyethyl 3-oxobutyrate, N,N-bis(2-hydroxyethyl)glycine, tris(hydroxymethyl)methylglycine, 2-furfural, 5-hydroxymethylfurfural, 2-acetylfuran, 5-methyl-2-furfural, ascorbic acid, butyl lactate, lactic acid Ethyl butyryl lactate, ethyl 3-hydroxybutyrate, ethyl 3-ethoxypropionate, ethyl 2-ethoxyacetate, ethyl 2-butoxyacetate, 2-hydroxyethyl acrylate, 1-vinyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolium ketone, 1,5-pentanediol, 1-(2-hydroxyethyl)-2-pyrrolidone, 1-(2-hydroxyethyl)-2,5-pyrrolidone, 5-methyl-2(3H)-furanone, 1-methyl-2-piperidinone, 4-aminobutyric acid, butyl glycolate, ethyl 2-mercaptopropionate, ethyl 4-oxopalanoate, diethyl maleate, dimethyl maleate, dimethyl fumarate, diethyl fumarate, dimethyl adipate, and dimethyl 3-oxopalanoate.

11. The method of claim 10, wherein the di(C1-C4) succinate is dimethyl succinate.

12. The method of claim 1 or 2, wherein the active phase of the catalyst is composed of cobalt and molybdenum.

13. The method of claim 1 or 2, wherein the catalyst is prepared according to a preparation method comprising the following stages: a) Contacting at least one hydrocarbon and at least one sulfur-containing compound with the oxide support such that the carbon- and hydrogen-containing graphite material can be formed on the oxide support. b) Then, the compound containing a Group VIb metal and the compound containing a Group VIII metal, as well as optionally phosphorus and / or at least one oxygen- and / or nitrogen- and / or sulfur-containing organic compound, are contacted with the oxide support containing the graphite material. To obtain catalytic precursors, c) The catalytic precursor is dried at a temperature below 200°C without subsequent calcination to obtain a dried catalyst. d) Optionally, the dried catalyst is activated in the presence of a sulfiding agent.

14. The method of claim 1 or 2, wherein the catalyst is at least partially used catalyst produced by a hydrotreating method.

15. The method of claim 1 or 2, wherein the gasoline is catalytic cracked gasoline.

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