Process for producing a catalyst support based on oxide(s) and at least one metal

Abstract

The present invention relates to a process for producing a recycled catalyst support comprising at least one Group VIII metal (M1) and not comprising any Group VIB metal. The process includes recycling at least a portion of one or both of the constituent elements of a source catalyst, namely the support or the M1 metal, preferably from Group VIII. It comprises at least one step of removing at least a portion of the carbon present on the source catalyst by washing and / or heat treatment at a temperature below 300°C, extraction of the M1 metal from said catalyst using an extraction solution to obtain a solution of the extracted metal(s) and a metal-depleted catalyst, a step of preparing a so-called "stabilized" catalyst support, and at least one step of impregnating the support with a fresh Group VIII metal solution. Figure for the abstract: 1

Description

Title of the invention: Process for producing a catalyst support based on oxide(s) and at least one metal. Technical field

[0001] The present invention relates to the production of catalysts comprising at least one metal from group VIIIB, and a support based on metal oxides. These catalysts are intended, in particular, for use in Fischer-Tropsch synthesis units. Prior art

[0002] Fischer-Tropsch synthesis processes make it possible to obtain a wide range of hydrocarbon fractions from the CO + H2 mixture, commonly called synthesis gas. The overall equation for the Fischer-Tropsch synthesis can be written as follows:

[0003] n CO + (2n+1) H2 -> CnH2n+2 + n H20

[0004] Fischer-Tropsch synthesis is at the heart of processes for converting natural gas, coal, or biomass into fuels or intermediates for the chemical industry. These processes are called GTL (Gas to Liquids) when natural gas is used as the initial feedstock, CTL (Coal to Liquids) for coal, and BTL (Biomass to Liquids) for biomass. In each of these cases, the initial feedstock is first gasified into a synthesis gas comprising a mixture of carbon monoxide and dihydrogen. The synthesis gas is then transformed primarily into paraffins by Fischer-Tropsch synthesis, and these paraffins can then be transformed into fuels by a hydroisomerization-hydrocracking process. Recently, the term e.The term "fuels" emerged and refers to the production of liquid fuels by Fischer-Tropsch synthesis from hydrogen produced by water electrolysis and CO produced by the reverse water-gas shift reaction between CO2 and the same hydrogen. The associated process can be called PTL (Power To Liquid) according to Anglo-Saxon terminology. The Fischer-Tropsch synthesis reaction can be carried out in different types of reactors (fixed bed, moving bed, or three-phase (gas, liquid, solid) for example, such as a perfectly stirred autoclave or bubble column), and the reaction products are notably characterized by being free of sulfur, nitrogen, or aromatic compounds.In an implementation in a bubble column type reactor (or "slurry bubble column" according to Anglo-Saxon terminology, or simply "slurry" in a simplified expression), which uses a catalyst divided into a fine powder state, typically on the order of a few tens of micrometers, . This powder forms a suspension with the reaction medium. The Fischer-Tropsch reaction proceeds conventionally between 1 and 4 MPa (10 and 40 bar), at temperatures typically ranging from 200°C to 350°C. The reaction is generally exothermic, which necessitates careful attention to the catalyst implementation. The catalysts used for the Fischer-Tropsch synthesis are primarily cobalt- or iron-based, although other metals can be used. However, cobalt and iron offer a good performance / cost compromise compared to other metals.

[0005] Conventional Fischer-Tropsch catalysts generally comprise an oxide support and an active phase based on Group VIII metals in their reduced forms, with the possible addition of dopants to, for example, improve activity, facilitate cobalt reduction, limit deactivation, or enhance long-chain selectivity. The preparation of these catalysts generally includes a step of impregnating the support with the metals, followed by drying and calcination to obtain the metal in its oxide form. Before their use in the Fischer-Tropsch reaction, the catalyst in its oxide form is reduced in the presence of a reducing agent, which may be hydrogen.

[0006] The use of a post-impregnation additive after the addition of cobalt, such as an organic acid, on a catalyst precursor obtained by dry impregnation with a cobalt salt followed by drying, has sometimes been described as improving activity. In this case, catalysts with a smaller cobalt particle size and higher methane selectivity have been obtained. (Cata Today, 228 (2014) 206-211 Lei Shi et al).

[0007] The catalysts used for the Fischer-Tropsch synthesis reaction are monofunctional, meaning that the support does not play a catalytic role per se and should preferably be inert if the target products are long hydrocarbon chains. Metallic cobalt is active in activating carbon monoxide and hydrogen and in promoting chain growth via the Schultz-Flory mechanism. The support is generally an oxide such as alumina, silica, silica-alumina, silica-alumina, or titanium.

[0008] During its operation in Fischer-Tropsch synthesis, the catalyst is deactivated by various processes, such as coke accumulation, sintering, the formation of mixed oxide species between the support and cobalt, poisoning by sulfur or nitrogen compounds, or carburization. Therefore, after a certain period, its replacement with fresh catalyst is necessary. In the case of a slurry process, catalyst can be withdrawn as needed, and fresh catalyst can be added at regular intervals to at least partially compensate for this depletion. the deactivation of the catalyst. The discharged catalyst can then be disposed of or possibly regenerated.

[0009] The discharged Fischer-Tropsch catalyst contains, within its porosity (and is embedded in it), wax (long hydrocarbon chains, solid at room temperature) produced by the reaction. Therefore, a first step of wax extraction by washing in the presence of a solvent is preferable before carrying out the actual regeneration of the Fischer-Tropsch catalysts. This process is economically and environmentally advantageous because it allows these catalysts to be reused in industrial units rather than being sent to landfills or recycled, most often through energy-intensive metallurgical processes whose objective is metal recovery.

[0010] US patent application 2010 / 0304955 describes, for example, a process for regenerating a spent Fischer-Tropsch catalyst. This process includes a dewaxing treatment to remove the wax from the catalyst before subjecting it to an oxidizing treatment at a pressure of between 4 and 30 bar, followed by a reduction process to obtain a regenerated catalyst. The dewaxing treatment may consist of hydrogenolysis, solvent washing, or a combination of both. After this treatment, the catalyst still contains between 5 and 20% residual carbon, which must be removed. This is removed by oxidation at temperature, and then the catalyst undergoes a reduction to produce a reduced catalyst. However, over time, catalytic performance can no longer be recovered, and it may be more economical to use fresh catalyst and dispose of the spent catalyst.

[0011] Generally speaking, the cobalt contained in Fischer-Tropsch catalysts is not currently recycled industrially for the manufacture of new catalysts. This is despite the relatively high purity of the spent catalyst, unlike conventional hydrotreating catalysts which can contain significant quantities of metallic pollutants such as arsenic and vanadium.

[0012] Processes have also been developed to recover metals from catalysts for recycling in the manufacture of new catalysts. For example, the process described in US patent 8986632 proposes recovering cobalt, ruthenium, and aluminum after removing heavy hydrocarbons from the spent catalyst by calcination using the Fischer-Tropsch synthesis. The catalyst, from which the hydrocarbons have been removed, is reacted with hydrogen and then undergoes alkaline fusion to obtain residues. These residues are then subjected to acid leaching, followed by cobalt precipitation in the presence of oxalic acid or ammonium oxalate. Next, the cobalt oxalate is reduced, and the metallic cobalt is dissolved by nitric acid to obtain crystallized cobalt nitrate hexahydrate after evaporation of the solution. Ruthenium and aluminum are recovered separately through treatments performed on the acid leaching effluent. Yields are at least 97% for cobalt, 95% for ruthenium, and 92% for aluminum. The crystallized metal salts must then be resuspended or used as molten salts before being used to prepare new catalysts.

[0013] US patent 7754635 proposes subjecting the spent Fischer-Tropsch catalyst to a dewaxing step, followed by hydrometallurgical leaching or extraction to separate the catalyst metal(s) from the catalyst support and then recover the separated metal(s). The dewaxing step is carried out in the presence of a supercritical or near-supercritical fluid to properly extract the wax from the spent catalyst without promoting the formation of a spinel between the metal(s) and the support (which occurs if the wax removal treatment is carried out at too high a temperature). The formation of this spinel is observed, for example, in patent application WO02 / 18663, in which the dewaxing step is carried out by a combination of high-temperature calcinations (600-1400°C) in the presence of air.The use of these oxidizing treatments leads to the formation of a spinel between the metal(s) and the support, making them resistant to leaching processes. Conversely, the use of a dewaxing treatment with a supercritical or near-supercritical fluid (C3-C12 hydrocarbon, alcohol, or water) allows the carbon content to be reduced below 1% (the maximum target content), without promoting spinel formation. A series of hydrometallurgical treatments allows the catalyst constituents to be selectively dissolved and then recovered in crystalline form by precipitation.

[0014] US patent application 2004 / 0219082 proposes a selective extraction of the different metals (cobalt and platinum) present in a Fischer-Tropsch catalyst by a series of steps allowing the recovery of the metals in ionic form: calcination of the wax present on the spent catalyst, treatment with hot sodium hydroxide to dissolve the aluminum support without solubilizing the cobalt or platinum. The solid residue containing the platinum and cobalt is then treated with a nitric acid solution to form cobalt nitrate, and the platinum present in the solid residue can then be recovered by acid attack to form chloroplatinic acid. This method makes it possible to recover metals in a pure form and reuse them for other applications.

[0015] These processes are technically interesting, but they are not without drawbacks. Indeed, they require a large number of operations, and these operations remain complex for extracting the metals of interest from spent catalysts in order to reuse them in new catalysts, which makes them difficult to implement. work, and therefore not very profitable. Transposition to an industrial scale thus remains very difficult to envisage.

[0016] An improved process was proposed in patent application WO22128491 A1, which describes the preparation of a recycled catalyst comprising at least one metal from Group VIB, and / or at least one metal from Group VIII, and an oxide-based support. The process includes recycling at least a portion of the metal(s) from a source catalyst comprising one or more metals in common with the recycled catalyst to be prepared, with extraction of the metal(s) from said source catalyst using an extraction solution to obtain a solution of the extracted metal(s), followed by impregnation of the support with an impregnation solution derived from said solution of the extracted metal(s) to obtain an impregnated substrate. The advantage of the described process lies in the fact that the extracted metal(s) remain in the liquid phase from extraction until impregnation.However, the potential advantages and disadvantages associated with pretreatment such as washing, decoking and / or grinding of the catalyst before metal extraction are neither described nor quantified.

[0017] Patent application EP4245870 A1 describes the recycling of one or more metals belonging to columns 8 to 12, present at least partially in the form of metal sulfides, in a porous material A comprising at least one mineral oxide and having a sulfur content of at least 2%. The process describes the following successive steps: heat treatment of material A at a temperature between 350 and 900°C, washing of the treated material with an aqueous solvent, and finally, extraction of the metal(s) by contact with a solution containing a carboxylic acid. The extracted metal(s) are then deposited onto a material B, different from material A, by contact with the extraction solution. The advantage of the invention is that it allows the recycling of metals present in highly contaminated porous materials (traps, adsorbents).

[0018] The aim of the invention is to propose new recycling processes for spent catalysts to enable the production of recycled catalyst supports exhibiting high hydrothermal resistance, particularly within the framework of the Fischer-Tropsch application. This involves developing improved processes that are simple to implement on an industrial scale, while allowing a high recovery rate of the constituent elements of the spent catalyst, such as the support and / or the metal(s), and guaranteeing high performance (activity, selectivity, lifetime) of the catalysts prepared from the recycled elements. Summary of the invention

[0019] The invention relates firstly to a process for producing a recycled catalyst support comprising at least one metal, preferably from group VIII and not comprising any metal from group VIB, characterized in that said process comprises the recycling of at least a part of one or both of the constituent elements of a source catalyst, namely the support or the metal M1, preferably from group VIII, the process comprising at least: - a step for removing at least part of the carbon present on the source catalyst, comprising at least one step of washing the source catalyst with an organic solvent, and / or at least one step of heat treating the source catalyst at a temperature below 300°C in the presence of a gas containing air, without a step of heat treating the catalyst in the presence of a gas chosen from oxygen and hydrogen, at a temperature above 300°C prior to the extraction step,

[0020] - Then, extraction by a metal extraction solution Ml and possibly of another metal chosen from the metals of group VIII (preferably platinum) and / or boron from said catalyst obtained from the step of removing at least part of the carbon, to obtain a solution of extracted metal(s), and a catalyst depleted in metal(s),

[0021] - then a step of preparing a so-called "stabilized" catalyst support comprising at least one metal, preferably from group VIII, according to one of the following methods or according to a combination of at least 2 of the following methods: - at least one step of impregnating a support with at least one impregnation solution derived from said solution of extracted metal(s), to obtain an impregnated support, said extracted metal(s) remaining in liquid phase from extraction until impregnation, followed by at least one calcination step at a temperature above 700°C, - at least one calcination step at a temperature above 700°C of the metal / metal depleted catalyst from the extraction step, - a step of preparing an acidic solution from at least a portion of said solution of extracted metal(s) and its atomization to obtain an atomized support which is then calcined at a temperature above 700°C,

[0022] - at least one impregnation step of the so-called stabilized support obtained at the end of the step preparation (according to one of the routes of said step or according to a combination of at least 2 of the routes) with a solution of group VIII metal not originating from the extraction step,

[0023] - a drying step and a calcination step of the impregnated support.

[0024] Preferably, the catalyst contains, after step a) of washing, a carbon content greater than 1% and less than 15%, expressed as a percentage by weight in relation to the total mass of said dry catalyst.

[0025] Preferably the source catalyst used in the process according to the invention does not have more than 2% sulfur and preferably not more than 1% and very preferably not more than 0.1% and even more preferably not more than 0.01%.

[0026] Another object of the invention is obtaining a catalyst from recycled catalyst support by impregnating it with a fresh solution of at least one metal from Group VIII, and not including any metal from Group VI. Definitions

[0027] In the sense of the present invention, the different embodiments presented can be used alone or in combination with each other, without limitation of combination.

[0028] In the sense of the present invention, the different parameter ranges for a given step, such as pressure ranges and temperature ranges, can be used alone or in combination. For example, in the sense of the present invention, a preferred range of pressure values ​​can be combined with a more preferred range of temperature values.

[0029] In the following text, the groups of chemical elements are given according to the CAS classification (CRC Handbook of Chemistry and Physics, publisher CRC Press, editor-in-chief DR Lide, 81st edition, 2000-2001). For example, group VIII according to the CAS classification corresponds to the metals of columns 8, 9 and 10 according to the new IUP AC classification, and group VIB to the metals of column 6.

[0030] In the following text, the expressions "between ... and ..." and "between ... and ..." are equivalent and mean that the limit values ​​of the interval are included in the range of values ​​described. If this were not the case and the limit values ​​were not included in the range described, such clarification will be provided by the present invention.

[0031] In the present description, the expression "greater than..." is understood as strictly greater than, and symbolized by the sign ">", and the expression "less than" as strictly less than, and symbolized by the sign "<".

[0032] According to the present invention, "extraction" is understood to mean that there is an extraction step, but that the extraction can be carried out by a single extraction operation or divided into a plurality of successive extraction operations.

[0033] According to the present invention, "impregnation" is understood to mean that there is an impregnation step, but that the impregnation can be carried out by one or a plurality of successive impregnation operations.

[0034] According to the present invention, the term "source catalyst" means a used catalyst, that is, one that has already been used in production, particularly in Fischer-Tropsch synthesis plants. This catalyst may have already been regenerated or rejuvenated several times prior to its use in the process according to the invention, but it will be considered as a source catalyst only in its used form, untreated after unloading from the Fischer-Tropsch II unit may therefore, for example, contain reaction products (waxes, oils) as well as coke.

[0035] According to the present invention, the term “washed” catalyst means the “source” catalyst treated by washing in order to extract all or part of the reaction products (waxes, oils) as well as a fraction of the coke.

[0036] According to the present invention, the term "support" (which will be impregnated with the impregnation solution) means a "new" oxide support, i.e., free of any metals, but also a so-called stabilized support, which has been obtained by dry impregnation of a metal on the support, followed by a calcination step or heat treatment carried out at high temperature to form a spinel or a solid solution between the metal and the alumina of the support.

[0037] The support can also, in the sense of the invention, be a metal-depleted catalyst from the catalyst extraction step from the step of removing at least part of the carbon according to the recycled catalyst support production process of the invention.

[0038] The invention thus proposes a new process in which at least a portion of the metal from the source catalyst is extracted in solution and advantageously remains in solution to be reused, according to one of the alternative methods of the invention, as a supplement to the impregnation solution to produce a recycled catalyst support. The extracted metal and / or the metal-depleted catalyst from the extraction step are recycled to obtain a recycled catalyst support exhibiting high hydrothermal resistance. Unlike many prior techniques, the invention does not seek to recover the metal from the source catalyst in solid, crystalline, and monometallic form, thereby avoiding numerous precipitation / filtration operations.Unlike the cases described in the literature, the extraction is carried out without having to implement a complete regeneration of the source catalyst; that is to say, the step of removing at least some of the carbon present on the source catalyst is partial and leads to leaving a carbon content greater than 1% in the catalyst before the extraction step.

[0039] An advantage of the present invention is that the process is easy and inexpensive to implement on an industrial scale while providing a recycled catalyst support for the preparation of high-performance catalysts. The invention also relates to the preparation of catalysts from the catalyst support produced according to the invention.

[0040] Unlike the prior art, the process for producing a recycled catalyst according to the invention includes at least one step of treating the source catalyst called step of removing at least part of the carbon, prior to liquid extraction, chosen from at least one of the following treatments:

[0041] - a step of washing the source catalyst with an organic solvent allowing extraction of the majority of the wax present around and within the porosity of the catalyst in the presence of a hot hydrocarbon solvent,

[0042] -and / or at least one heat treatment step of the source catalyst at a temperature below 300°C, allowing decoking by mild heat treatment (in the presence of oxygen-depleted air, low temperature, slow ramps). The controlled heat treatment, carried out under mild conditions, will facilitate the extraction of the metal.

[0043] An advantage of the present invention lies in the fact that these preliminary treatments are intended to make extraction more efficient through mechanical, physical, or chemical processes. Removing at least some of the carbon in the form of waxes and / or coke from the source catalyst improves contact between the extraction solution and the metals to be extracted contained in the source catalyst.

[0044] As mentioned above, the process according to the invention is preferably aimed at producing a Fischer-Tropsch catalyst.

[0045] The spent catalyst used in the recycling process according to the invention may have undergone cycles of regeneration and / or rejuvenation, but when the liquid metal extraction process is applied to it in the process according to the invention, it will be worn out.

[0046] The catalyst support to be produced is preferably based on aluminum oxide, and possibly on aluminum oxide and silicon. The source catalyst is preferably of the same type, and contains at least the same metal, preferably from Group VIII, as the recycled catalyst support to be produced. The metal, preferably from Group VIII, of the support and / or the catalyst to be produced is preferably the same and is preferably cobalt.

[0047] The recycled catalyst support according to the invention is said to be "stabilized" by a metal, preferably from Group VIII. A "stabilized" support is understood to be a support containing at least a portion of the metal and having undergone a calcination step at a temperature above 700°C. The Group VIII metal used to prepare the "stabilized" support may be introduced during the preparation of the support or by an impregnation step of said metal after the preparation of said support. The invention also relates to the catalyst produced from the recycled catalyst support according to the invention by the process described above, which therefore comprises one or more recycled metals and / or a recycled support. It may also contain at least a portion of one or more recycled metals and / or "fresh" metals. LIST OF FIGURES

[0048] [Fig.1]

[0049] Figure 1 shows a block diagram of a first variant of the installation implementing the process according to the invention. In this variant, the metal-depleted source catalyst is calcined at high temperature to provide a recycled catalyst support according to the invention before the latter is impregnated with a fresh metal solution and then heat-treated to produce a catalyst according to the invention.

[0050] [Fig.2]

[0051] Figure 2 shows the block diagram of a second variant of the installation implementing the process according to the invention. In this variant, the metal-depleted source catalyst is calcined to provide a recycled catalyst support, and then the extracted metal solution is impregnated onto this same previously calcined support to produce a stabilized support. Finally, a catalyst is prepared by impregnating and then heat-treating this support.

[0052] [Fig.3]

[0053] Figure 3 shows the block diagram of a third variant of the installation implementing the process according to the invention. In this variant, the extracted metal solution is added to an aluminum or silicon-based solution to produce a suspension, which is then atomized to produce a dried catalyst support. This support is then calcined at high temperature to produce a recycled catalyst support. Finally, a catalyst is prepared by impregnating and then heat-treating this support.

[0054] The figures are highly schematic and do not necessarily represent all the operations that may be involved in the process according to the invention. Identical reference numerals from one figure to another refer to the same operation / component / device. DESCRIPTION OF THE FIGURES

[0055] In [Fig. 1], step W of catalyst processing leads to the production of a spent catalyst stream, source 1. This is treated in washing step A1 to generate a washed catalyst stream 2, which is then treated in heat treatment step A2 at a temperature below 300°C to generate a catalyst 3 from which at least some of the coke and wax have been removed. The catalyst 3 is then contacted with an extraction solvent 4 in step B to produce, on the one hand, a metal-depleted catalyst 5 and, on the other hand, a metal solution containing the extracted metal 6. The metal-depleted catalyst 5 is then heat-treated in step H to obtain a recycled catalyst support 7 according to the invention. This latter catalyst support 7 is then impregnated with a "fresh" metal solution 13 in step K to lead to an impregnated support 8 which is heat-treated in step L to lead to a catalyst 9 according to the invention and containing a support 7 called recycled.

[0056] In [Fig.2], step W of implementing a catalyst leads to obtaining a spent catalyst stream source 1. The latter is treated in the washing step A1 to generate a washed catalyst stream 2 which is then treated in the heat treatment step A2 at a temperature below 300°C to generate a catalyst 3 from which at least part of the coke and wax have been removed. The catalyst 3 is then brought into contact with an extraction solvent 4 in step B to lead on the one hand to a metal-depleted catalyst 5 and to a metal solution containing the extracted metal 6. The metal-depleted catalyst 5 is then heat-treated in step H to obtain a recycled catalyst support 14 which is then impregnated in step F with the metal solution 6, to lead to an impregnated support 15 which is then heat-treated in step G to lead to a recycled catalyst support 7 according to the invention.The modified support 7 is then impregnated with a "fresh" metallic solution 13 in step K to produce an impregnated support 8 which is heat-treated in step L to produce a catalyst 9 according to the invention and containing a so-called recycled support 7.

[0057] In [Fig.3], step W of implementing a catalyst leads to obtaining a spent catalyst stream source 1. The latter is treated in the washing step A1 to generate a washed catalyst stream 2 which is then treated in the heat treatment step A2 at a temperature below 300°C to generate a catalyst 3 from which at least part of the coke and wax have been removed. The catalyst 3 is then brought into contact with an extraction solvent 4 in step B to lead on the one hand to a metal-depleted catalyst 5 and to a metal solution containing the extracted metal 6. The metal solution 6 is then mixed in a step I with a solution containing the precursors of an oxide support 21 to lead to a suspension 14 which is then atomized in step J to lead to a dried modified support 15 which is itself calcined in a step G to lead to a recycled catalyst support 7 according to the invention.The recycled catalyst support 7 is then impregnated with a "fresh" metal solution 20 in step K, the metal solution 20 being prepared during step F' by dissolving in a solvent 18 one or more metal precursor(s) 19 to lead to an impregnated support 8 which is heat-treated in step L to lead to a catalyst 9 according to the invention and containing a so-called recycled catalyst support 7.

[0058] Any combination resulting from the association of sequences of steps represented in one or the other of the figures described above remains covered without said figures limiting the scope of the invention. Description of the implementation methods

[0059] The source catalyst of the process according to the invention is a catalyst comprising at least one oxide support and at least one metal from Group VIII, but not comprising any metal from Group VIB, and optionally at least one other metal selected from the metals of Group VIII, and preferably platinum and / or boron. The term "source" according to the invention has been defined above.

[0060] The source catalyst comprises at least one metal Ml belonging to Group VIII, and optionally at least one other metal selected from the metals of Group VIII, preferably platinum, an oxide support, and optionally dopants. It comprises carbon in the form of coke and / or long hydrocarbon chains as described below.

[0061] The active phase of the source catalyst preferably comprises at least one metal Ml from group VIII and is preferably made up of a group VIII metal. The group VIII metal present in the active phase of the catalyst is preferably cobalt.

[0062] In a preferred embodiment, the source catalyst and the recycled catalyst to be produced may contain other doping elements, preferably selected from alkali metals, Group VII metals, Group I metals, Group IV metals, phosphorus, and boron. Group I metals are preferably selected from silver and gold, Group VII metals from rhenium and manganese, Group IV metals from titanium and zirconium, and alkali metals from potassium, calcium, and magnesium.

[0063] The spent Fischer-Tropsch catalyst can be obtained from any known process involving a fixed bed, bubbling bed, or bubble column catalyst. It can be in the form of beads, extruded material, or powder, depending on the process from which it originates.

[0064] Preferably, the spent catalyst, obtained from a Fischer-Tropsch bubble column process, is withdrawn with a mixture of heavy hydrocarbons (waxes) produced by the reaction. At this stage, the catalyst metal is still at least partially in its metallic form (zero oxidation state). Preferably, it is in powder form.

[0065] The solid obtained after this treatment can then be calcined under controlled conditions to remove a larger fraction of the hydrocarbons still contained in the catalyst after extraction. This calcination is advantageously carried out in the presence of oxygen-depleted air (10% by volume) following a succession of controlled temperature ramps and plateaus to avoid exothermic reactions related to the Combustion of coke and linear hydrocarbon molecules. Generally, carbon remains present after this heat treatment step.

[0066] The oxide support of said catalyst source of the process according to the invention is usually a porous solid chosen from the group consisting of: aluminas, silica, silica-aluminas or even titanium or magnesium oxides used alone or in mixture with alumina or silica alumina.

[0067] In another preferred case, the oxide present in the support of said catalyst source of the process according to the invention is a silica alumina containing at least 70% by weight of alumina relative to the total weight of the composite support. The silica content in the support is at most 30% by weight relative to the total weight of the support, most often less than or equal to 20% by weight, preferably less than or equal to 15% by weight.

[0068] According to a particularly preferred embodiment, the support of the source catalyst is made of alumina, silica or silica-alumina.

[0069] The support is advantageously in the form of irregular and non-spherical beads, extrudates, pellets or agglomerates whose specific shape may result from a crushing step.

[0070] According to a particularly preferred embodiment, the support of the source catalyst is in the form of a powder with an average particle size of between 30 and 200 pm, preferably between 40 and 150 pm and even more preferably between 50 and 120 pm.

[0071] The content of group VIII metal Ml is between 10 and 35% by weight of group VIII metal relative to the total weight of the dry catalyst, preferably between 15 and 30% by weight, and preferably between 17 and 25% by weight.

[0072] The catalyst source of the process according to the invention may also include boron as a dopant. The dopant is an added element which, in itself, has no catalytic character but which can improve the stability of the catalyst, limit its deactivation, or facilitate the reduction of the metal or increase the catalytic activity of the active phase.

[0073] The boron content in said source catalyst is then preferably between 0.05 and 0.25% by weight expressed as Boron element relative to the total weight of the dry catalyst, preferably between 0.07 and 0.015% by weight expressed as B, and most preferably between 0.09 and 0.12% by weight expressed as Boron element.

[0074] The source catalyst of the process according to the invention may also comprise, in addition to the Group VIII metal M1, another Group VIII metal and preferably a noble metal, preferably selected from platinum, palladium, ruthenium, and rhenium, alone or in mixtures. The noble metal content in said source catalyst is then preferably between 25 and 500 ppm by weight expressed as an element relative to to the total weight of the dry catalyst, preferably between 25 and 100 ppm weight expressed in elements, and most preferably between 30 and 70 ppm weight expressed in elements.

[0075] According to the invention, the catalyst does not comprise any metal from group VIB and preferably does not comprise any metal selected from Molybdenum and tungsten.

[0076] The metal Ml of the source catalyst is preferably essentially in reduced form (zero oxidation state).

[0077] The source catalyst of the process according to the invention advantageously does not contain sulfur or nitrogen. The sulfur content in said source catalyst is preferably less than 1% by weight expressed as an element relative to the total weight of the dry catalyst, preferably less than 0.1%, and most preferably less than 0.01% by weight. The nitrogen content in said source catalyst is preferably less than 0.1% by weight expressed as an element relative to the total weight of the dry catalyst, preferably less than 0.05%, and most preferably less than 200 ppm by weight.

[0078] The catalyst source of the process according to the invention may comprise coke but also non-aromatic carbon from the products of the Fischer-Tropsch reaction, essentially in the form of long paraffin chains. It should be noted that the term "coke" in this application refers to a hydrocarbon-based substance deposited on the surface of the catalyst during its use, highly cyclized and condensed, and having an appearance similar to graphite.

[0079] The coke and carbon content of the source catalyst directly discharged from the FT reactor before its implementation in the process according to the invention is advantageously greater than 30%.

[0080] According to one embodiment of the invention, the source catalyst of the process according to the invention may comprise or be composed of the fines produced during the unloading operation of the spent catalyst from the industrial unit from which it is removed, or during regeneration. In this case, and according to a variant of the process, the fines may be eliminated at any stage of the process of the invention, and in particular before the metal(s) extraction stage or before the metal(s) impregnation stage.

[0081] The steps in the manufacturing process of a recycled catalyst support according to the invention

[0082] According to the invention, the object of the invention is a process for producing a recycled catalyst support comprising at least one metal from Group VIII and not comprising any metal from Group VIB, characterized in that said process comprises the recycling of at least a portion of one or both of the constituent elements of a source catalyst, namely the support or the metal M1, preferably from Group VIII, the process comprising at least:

[0083] - a step of removing at least some of the carbon present on the catalyst source comprising at least one step of washing the source catalyst with an organic solvent, and / or at least one step of heat treatment of the source catalyst at a temperature below 300°C in the presence of a gas containing air, without a step of heat treatment in the presence of a gas selected from oxygen, hydrogen sulfide and hydrogen, at a temperature above 300°C, - Then, extraction by an extraction solution of the metal Ml and possibly of another metal selected from the metals of group VIII (preferably platinum) and / or of the boron of said catalyst from the step of removing at least part of the carbon, to obtain a solution of extracted metal(s), and a catalyst depleted in metal(s),

[0084] - then a step of preparing a catalyst support comprising at least one metal, preferably from group VIII, said support being obtained by one of the following methods or by a combination of at least 2 of the following methods: - by at least one step of impregnating a support with at least one impregnation solution derived from said solution of extracted metal(s), to obtain an impregnated support, said extracted metal(s) remaining in liquid phase from extraction until impregnation, followed by at least one calcination step at a temperature above 700°C,

[0085] - by at least one calcination step at a temperature above 700°C of the metal(s) depleted catalyst from the extraction stage,

[0086] - by preparing an acidic solution from at least a part of said solution of extracted metal(s) and its atomization to obtain an atomized support which is then calcined at a temperature exceeding 700°C,

[0087] - at least one impregnation step of the so-called stabilized support obtained at the end of the step preparation (according to one of the routes of said step or according to a combination of at least 2 of the routes) with a solution of group VIII metal not originating from the extraction step,

[0088] - a drying step and a calcination step of the impregnated support.

[0089] Steps (a) of removing at least part of the carbon present on the catalyst source: preliminary step(s) to extraction

[0090] Before the metal extraction step, a step to remove at least part of the carbon is necessary, in particular to remove the majority of the wax (long paraffins with up to 90 carbon atoms) solid at ambient temperature.

[0091] According to the invention, the process includes a step of removing at least some of the carbon present on the source catalyst, comprising at least one step of washing the source catalyst with an organic solvent, and / or at least a heat treatment step of the source catalyst at a temperature below 300°C in the presence of a gas containing air, without a heat treatment step at a temperature above 300°C and carried out in the presence of a gas chosen from oxygen, hydrogen sulfide and hydrogen prior to the extraction step.

[0092] The mandatory step (a) consists of partially removing the carbon, in the form of waxes and / or coke deposited on the surface of the catalyst (hydrocarbons and coke) before the step (b) of metal extraction.

[0093] According to the invention, the washing step a1) of the source catalyst is carried out in the presence of an organic solvent preferably maintained at its boiling point to remove all or part of the coke and products of the Fischer-Tropsch reaction (wax) possibly deposited on the catalyst.

[0094] The organic solvent used in the washing step a1) is preferably maintained at its boiling point and is preferably chosen from aromatic solvents, preferably toluene and / or xylene, linear hydrocarbon solvents comprising between 3 and 12 carbon atoms, preferably hexane and / or heptane, and linear or branched alcohols comprising between 3 and 12 carbon atoms, alone or in mixture.

[0095] In a preferred embodiment, the organic solvent of the washing step a1) is an aromatic solvent selected from toluene and xylene, alone or in mixture.

[0096] This washing step (a) of the wax preferably comprises washing the source catalyst with a hydrocarbon solvent at its boiling point (for example, toluene and / or xylene), at a temperature between 80°C and 180°C, preferably between 90°C and 150°C, for a duration of between 8 and 24 hours, preferably between 12 and 20 hours. The tool used in the laboratory to perform this washing is a Soxhlet apparatus, which allows for thorough extraction of the hydrocarbon chains present in and on the catalyst by recirculating the solvent over the catalyst.

[0097] For example, the at least partially spent source catalyst is extracted from the reactor and sent to an installation allowing the extraction of wax and part of the coke in order to carry out the washing of the catalyst in said installation.

[0098] The washing step is advantageously carried out in a stream of organic solvent heated to its boiling point. The solvent vaporizes and then flows through the catalyst bed to be washed, in a Soxhlet-type washing column, carrying away carbon in the form of long chains and coke. The washing is carried out for a duration of between 1 and 20 hours, and preferably between 5 and 15 hours.

[0099] According to the invention, step a1) is carried out without a heat treatment step at a temperature above 300°C and carried out in the presence of a gas chosen from oxygen and hydrogen.

[0100] Preferably, the catalyst contains, after the washing step a1), a carbon content greater than 1% and less than 15%, expressed as a percentage by weight relative to the total weight of said dry washed catalyst.

[0101] Preferably, the carbon content, expressed as a percentage by weight relative to the total weight of the dry washed catalyst, is between 2 and 15% by weight, preferably between 4 and 12% by weight, and most preferably between 6 and 10% by weight. The coke content is determined according to ASTM D5373.

[0102] According to the invention, at least one heat treatment step a2) of the source catalyst at a temperature below 300°C in the presence of a gas containing air is carried out alone or jointly with said step al) of washing.

[0103] Preferably, the heat treatment step a2) is carried out after the washing step a1) in the presence of a solvent and consists of removing part of the residual carbon by heat treatment preferably in the presence of a gas containing oxygen, generally air.

[0104] Preferably, the gas flow rate in terms of flow rate per unit volume of the at least partially spent catalyst is preferably 20 to 2000 NL.h-1, more preferably 30 to 1000 NL.h-1, and particularly preferably 50 to 300 NL.h-1. The total duration of the heat treatment step a2) is preferably 4 hours or more, more preferably 8 hours or more, and particularly preferably 15 hours or more.

[0105] According to the invention, step a2) is carried out at a temperature below 300°C, preferably between 100 and 300°C, preferably between 150 and 300°C and most preferably between 200 and 270°C.

[0106] The source catalyst from step a), and in particular from steps a1a and / or a2, is composed of the oxide support and the active phase formed of at least one metal from Group VIII and not comprising any metal from Group VIB, and optionally another metal selected from the metals of Group VIII (preferably platinum) and / or boron. The regenerated catalyst is characterized by a specific surface area of ​​between 20 and 300 m² / g, preferably between 50 and 280 m² / g, preferably between 80 and 240 m² / g, most preferably between 100 and 200 m² / g.

[0107] The porous volume of the source catalyst (used and then regenerated here) is generally between 0.2 cm3 / g and 1 cm3 / g, preferably between 0.3 cm3 / g and 0.8 cm3 / g, most preferably between 0.4 and 0.6 cm3 / g.

[0108] The catalyst from step a) and in particular from steps a1) and / or a2) contains residual carbon at a content greater than 1% and less than 15% by weight relative to the total weight of the catalyst, preferably a carbon content between 3% and 15% by weight relative to the total weight of the catalyst, preferably between 5% and 12% by weight and particularly preferably between 6% and 10% by weight.

[0109] It should be noted that the term "residual carbon" in this application means carbon (coke) and possibly long paraffins present in the porosity remaining in the washed catalyst and possibly regenerated after washing and regeneration of the spent Fischer-Tropsch catalyst. This residual carbon content in the regenerated hydrotreating catalyst is measured according to ASTM D5373. Extraction step (b)

[0110] According to the invention, the process includes a step b) of extraction by an extraction solution of the metal Ml of group VIII present on the source catalyst and preferably cobalt, and possibly of another metal chosen from the metals of group VIII and preferably platinum and / or boron of said catalyst from the step of removing at least part of the carbon, to obtain a solution of extracted metal(s).

[0111] According to this step, advantageously the catalyst from step a) of removing at least part of the carbon is brought into contact with an extraction solution containing at least one solvent.

[0112] Preferably, said extraction solution comprises a polar protic solvent, preferably selected from the group consisting of methanol, ethanol, and water, or alternatively a mixture of water and ethanol, water and methanol, or water and citric acid. In a specific embodiment, the extraction can be carried out in the presence of water alone, without the addition of any organic agent.

[0113] The extraction solvent may advantageously be organic or aqueous, or both. Most preferably, the solvent used in the extraction solution consists mainly of water and may advantageously also include an organic compound. In the case of an aqueous solution, the pH of said solution may advantageously be modified by the optional addition of an acid or a base. The extraction solution generally has a pH between 0.1 and 8.5, preferably between 0.5 and 6, and preferably between 1 and 4.

[0114] Where the solvent is organic, it may include any polar protic solvent known to those skilled in the art. Preferably, the solvent is an organic compound having complexing and possibly acidic properties, preferably either at least one compound having both properties, or a combination of at least one acidic compound and at least one complexing compound, or only at least one complexing compound. Said organic compound is chosen from a compound having one or more chemical functions selected from among a carboxylic acid, phosphonic acid, alcohol, ether, aldehyde, ketone, ester, carbonate, amine, nitrile, imide, oxime, urea, and amide function, or compounds including a furanic ring, or sugars.

[0115] In a preferred embodiment, said organic solvent (or at least one of them when there are several) may be selected from at least one of the following compounds: formic acid, acetic acid, oxalic acid, malonic acid, glutaric acid, glycolic acid, lactic acid, tartronic acid, citric acid, tartaric acid, pyruvic acid, γ-ketovaleric acid, succinic acid, acetoacetic acid, gluconic acid, ascorbic acid, phthalic acid, salicylic acid, maleic acid, malic acid, fumaric acid, acrylic acid, 2-hydroxy-4-methylthiobutanoic acid, glutamic acid, N-acetylglutamic acid, alanine, glycine, histidine, aspartic acid, N-acetylaspartic acid, 4-aminobutanoic acid, 1,2-cyclohexanediaminetetraacetic acid, ethylenediaminetetraacetic acid (EDTA), nitrilotriacetic acid (NTA), iminodiacetic acid (IDA),N-(2-hydroxyethyl)ethylenediamine-N,N',N'-triacetic acid (HEDTA), diethylenetriaminepentaacetic acid (DTPA), bicine, tricine, L-hydroxyethylidene-L,L-diphosphonic acid (HEDP or etidronic acid), nitrilotris(methylenephosphonic) acid, diethylenetriaminepentakis(methylenephosphonic) acid, alone or in mixtures.

[0116] Most preferably, said organic solvent is selected from acetic acid, oxalic acid, malonic acid, glutaric acid, lactic acid, citric acid, tartaric acid, succinic acid, ascorbic acid, salicylic acid, maleic acid, malic acid and even more preferably, from citric acid, acetic acid, oxalic acid, and lactic acid, alone or in mixture.

[0117] The chemical compounds in this group do indeed exhibit both acidic and complexing properties.

[0118] In a preferred embodiment, said organic solvent (or at least one of them) may be selected from at least one of the following compounds: dimethylglyoxime, methyl acetoacetate, ethyl acetoacetate, ethyl lactate, methyl glycolate, ethyl glycolate, dimethyl malate, diethyl malate, dimethyl tartrate, diethyl tartrate, ethyl 3-hydroxybutanoate, ethyl 3-ethoxypropanoate, methyl 3-methoxypropanoate, methyl 3-(methylthio)propanoate, ethyl 3-(methylthio)propanoate, ethylene glycol, diethylene glycol, triethylene glycol, a polyethylene glycol (with a molecular weight between 200 and 1500 g / mol), the propylene glycol, glycerol, 2-butoxyethanol, 2-(2-butoxyethoxy)ethanoyl, 2-(2-methoxyethoxy)ethanol, triethylene glycol dimethyl ether, a crown ether, acetophenone, 2,4-pentanedione, pentanone, glucose, fructose, sucrose, sorbitol,xylitol, mannitol, y-valerolactone, propylene carbonate, octylamine, N,N-diethylformamide, N,N-dimethylformamide, N-methylformamide, N,N-dimethylacetamide, propanamide, l-methyl-2-, pyrrolidinone, tetramethylurea, N,N'-dimcthylurcc, acetonitrile, lactamide, furfurol, 2-furaldehyde, 5-hydroxymethylfurfural, ethyl 3-hydroxybutanoate, 2-hydroxyethyl acrylate, l-vinyl-2-pyrrolidinone, N,N,N',N'-tetramethyltartramide, 3-hydroxypropionitrile and N,N'-bis(2-hydroxyethyl)ethyl enediamine, alone or in mixture.

[0119] The chemical compounds in this group do indeed exhibit complexing properties.

[0120] Advantageously, the extraction solution also comprises at least one mineral acid, in particular phosphoric acid, nitric acid, or boric acid. This combination of a complexing organic compound and a mineral acid has proven very effective, allowing both good extraction of the target metals and, in particular, creating a sufficiently acidic environment, especially when the impregnation of the support using this solution must be carried out in an acidic environment, and even more so when the final catalyst must contain phosphorus when phosphoric acid is chosen.

[0121] The concentration of each organic compound in the extraction solution is defined so that the molar ratio of organic compound to extracted metals is between 0.2 and 25, preferably between 0.2 and 11, preferably between 0.2 and 5, preferably between 0.4 and 2, and preferably between 0.4 and 1.2.

[0122] When several organic compounds are present, the different molar ratios apply to each of the organic compounds present.

[0123] In one embodiment according to the invention, the extraction solution may also contain phosphorus. The presence of phosphorus in the extraction solution promotes the extraction of metals. The addition of phosphorus in the form of phosphoric acid (H3PO4) also lowers the pH of the solution, which is also generally beneficial for the extraction of metals contained in the source catalyst. Other mineral acids besides phosphoric acid may also be used, in particular, nitric acid or boric acid.

[0124] The preferred phosphorus precursor is phosphoric acid H3PO4, but its esters and salts, such as ammonium phosphates, are also suitable, as are polyphosphates. Without being linked to any specific theory, it appears that combining phosphoric acid with an organic acid having a pKa greater than 1.5, i.e., a weak organic acid, results in a synergistic effect on metal extraction that is not predictable when using phosphoric acid or the organic acid alone. Extraction in the presence of two specific acids allows for very good dissolution of the metal phases.

[0125] In one embodiment according to the invention, the extraction solution may also contain an oxidant to promote the extraction of metals. The preferred oxidant in the extraction solution is hydrogen peroxide. When an oxidant is present, the concentration is generally between 0.1 and 5.0 mol / L.

[0126] Generally, the operating conditions of step (b) are chosen to maximize the extraction of the metals contained in the source catalyst, while minimizing the dissolution of the metal(s) contained in the support of said source catalyst, and limiting the quantity of organic compound so that it is not in excessive excess relative to the optimal quantity of organic compound required for the impregnation step to obtain high-performance catalysts. The aim is also to minimize the quantity of extraction solution to be used, in order to obtain the most concentrated metal solution possible at the end of the extraction without reaching the solubility limit, which would lead to metal precipitation: this limits the need to concentrate the solution before using it in the impregnation solution or as the impregnation solution itself.

[0127] The catalyst obtained from the step of removing at least part of the carbon is brought into contact with the extraction solution under the following conditions: - temperature: between 10 and 150°C, in particular between 15 and 95°C, - pressure: between atmospheric pressure and 20 bar, in particular at atmospheric pressure or at most 10 bar - duration: between 1 minute and 20 hours, preferably between 5 and 300 minutes, preferably between 5 and 180 minutes.

[0128] Preferably, the tool(s) performing the contacting operation do not have heating equipment, and the contact temperature is regulated by the temperature of the extraction solution. The temperature of the extraction solution can be between 15, 20, or 25°C and 95°C, and preferably between 30°C and 90°C, and even more preferably between 50°C and 85°C. It can therefore be at ambient temperature, or have been heated, for this specific contacting step. It can also be at a given temperature, particularly above ambient temperature, because it originates, at least in part, from the recycling of liquid effluents produced in the process according to the invention and already being within this temperature range.

[0129] The amount of extraction solution used in this step is preferably as small as possible to obtain the desired effect, as indicated above. Preferably, this step (b) is carried out by contacting the source catalyst with a volume of said solution between 1.5 and 60 times the volume of the source catalyst. Preferably, the volume of said solution is between 2 and 30 times the volume of the catalyst source and more preferably between 2 and 20 times the volume of the catalyst source.

[0130] All contact methods, whether single-step or multi-step following a co-current, counter-current, or cross-current pattern, are possible for implementing step (b) in continuous mode. Batch contact can also be implemented. By way of illustration, contact can be achieved by immersion, or under the flow of the extraction solution, for example, by distributing the trickling extraction solution over the source catalyst, which may be set in motion.

[0131] At the end of step (b), the solution is separated from the solid residue to obtain, on the one hand, a metal-depleted catalyst, and, on the other hand, the metallic solution of the extracted metal(s) to be used in the following steps (c), (d), (e), (f), (g), (h), (i), (j), (k), (1), or (m). Preferably, the residual metal content of the metal-depleted catalyst (sum of the contents of the different metals contained in said catalyst expressed as oxide) is less than 12 wt%, preferably less than 10 wt%, and most preferably less than 7 wt% and greater than 3 wt%, and preferably greater than 5 wt%. Any liquid / solid separation method can be used, such as, for example, filtration or dewatering, for example, gravity separation. Preferably, the separation step is carried out using a filter press.

[0132] The process according to the invention includes, either mandatorily or optionally, the following steps (successive but not necessarily consecutive):

[0133] - at least one step (al1, a2) of processing the source catalyst,

[0134] - the extraction (b) by an extraction solution of the metal(s) of said catalyst resulting from steps a1) and / or a2), to obtain a solution of extracted metal(s) and a catalyst depleted in metal(s),

[0135] - at least one optional step (c) of purifying the metal / metals solution extract(s), produced in step (b) to remove all or part of any impurities,

[0136] - at least one optional step (d) of concentrating the metal / metals solution extract(s)

[0137] - at least one optional step (e) of adjusting the composition of the solution of extracted metal(s) from step (b), (c) or (d)

[0138] - a step of preparing a so-called "stabilized" catalyst support comprising at minus one metal, preferably from group VIII, by one of the following methods or by a combination of at least 2 of the following methods:

[0139] - at least one impregnation step (f) of a support by at least one solution impregnation from said solution of extracted metal(s), to obtain an impregnated support, said extracted metal(s) remaining in liquid phase since extraction to the point of impregnation, followed by at least one step (g) of drying and calcination at a temperature above 700°C,

[0140] - at least one calcination step (h) at a temperature above 700°C metal(s) depleted catalyst from step b) of extraction,

[0141] - a step of preparing (i) an acidic solution from at least a part of said solution of extracted metal(s) and its atomization in a step (j) to obtain an atomized support which is then calcined in a step (g') at a temperature above 700°C.

[0142] - at least one liquid impregnation step (k) of the catalyst support recycled obtained at the end of one of the steps h) and / or g) and / or g') with a metallic solution derived from so-called fresh metal precursors,

[0143] - a drying and calcination step (1) of the impregnated support obtained in step (k).

[0144] - advantageously a reduction step (m) of the dried and calcined impregnated support obtained in step (1)

[0145] It should be noted that step (b) is carried out before steps (i), (h) or (f), and that the drying and calcination step (g) is carried out after step (f). The reduction step (1) is carried out after step (k). The optional steps (c), (d), (e) are preferably carried out in the order of the steps indicated above, i.e. step (c), then (d) then (e), but they may also be carried out in a different order (such as dce, or dec, or ced, or ecd, or edc).

[0146] It is also noted that steps (f) and (g) on ​​the one hand and (k) and (1) on the other hand can be followed respectively by at least one further impregnation step (f”) and a drying and calcination step (g”), respectively followed by an impregnation step (j”) and a drying and calcination step (k”).

[0147] Preferably, three steps of impregnation, drying and calcination are carried out. In the case where steps (f”) or (j”) are intercalated as mentioned above, these can advantageously be carried out using an impregnation solution from said extracted metal(s) solution obtained in step (b), (c), (d) or (e), or from an impregnation solution comprising “fresh” cobalt, i.e. not from step b) of extraction according to the invention.

[0148] Advantageously, the process for producing a recycled catalyst may include at least one step of treating the extracted metal(s) solution before impregnation, selected from at least one of the following treatments: purification, concentration, adjustment of the composition of said solution by dilution, or modification of the solution's composition by adding or removing, totally or partially, at least one compound. The purpose of these post-treatments is to bring the extraction solution into the conditions required to serve as an impregnation solution. Concentration, therefore, by removing at least a portion of the solvent / Adding non-metallic compounds to the solution will make it more effective and bring it closer to the concentrations required for impregnation in conventional processes for impregnating new catalysts. The same is true by, for example, supplementing the solution with constituent elements of the catalyst to be produced, particularly supplementing it with at least one metal not present in the solution, or present in insufficient quantity. Step (c) (Optional)#: Purification

[0149] The process according to the invention may advantageously include an optional step (c) of purifying the extracted metal(s) solution produced in step (b) to remove all or part of any impurities that may be contained in said metal solution, in particular impurities potentially present on the source catalyst or related to partial dissolution of the support of said catalyst. Step (c) may advantageously be carried out in a single step or in several successive steps.

[0150] If the extracted metal(s) solution contains suspended solids after the separation step, at the end of step (b), any known method for removing these suspended solids can advantageously be used in step (c). Preferably, this removal is carried out by filtration (e.g., microfiltration and ultrafiltration using a cross-flow filter). Other methods include centrifugation or coagulation.

[0151] For dissolved impurities, such as for example aluminum or silicon-based compounds, all known methods may be used in this step (c), in particular and preferably, sorption on solid, precipitation and solvent extraction, taking care not to remove at the same time the metals of interest which have been extracted.

[0152] If the purification step (c) results in a second, undesirable solution containing solvent, this solution may advantageously be recycled to the extraction step (b) if its impurity content remains low. Step (d) (Optional): Concentration

[0153] The process according to the invention may also advantageously include a step (d) of concentrating the extracted metal(s) solution from step (b) or (c) by removing a portion of the solvent and all or part of the organic compound contained in said metal solution. This step may be necessary if the metal concentrations are too low compared to the concentrations required to achieve impregnation. Any known method for removing a portion of a solvent from a solution is considered. Step (d) may advantageously be carried out in a single step or in several successive steps. All or part of the solvent containing or not of organic compound, extracted from said metallic solution at this step (d), can advantageously be recycled at the extraction step (b).

[0154] Preferably, and particularly when the extracted metal(s) solution is an aqueous solution, step (d) is advantageously carried out by evaporation concentration. In this case, neutralization is preferably performed so that the effluent enters the evaporator at a pH of 5 to 7. This pH control helps to limit co-distillation, unless it is desired for the co-removal of the solvent and part of the organic compound, and also to minimize the precipitation of metal oxides. Preferably, all or part of the distillate is advantageously recycled in the extraction step (b).

[0155] When only the removal of part of the solvent is desired, besides evaporation concentration, the preferred techniques are membrane techniques, and, very preferably, nanofiltration, reverse osmosis and pervaporation, solvent extraction or cryoconcentration.

[0156] When one wants to remove solvent and organic compound(s) when they are used, a preferred technique is evaporation concentration.

[0157] - Step (e) of adjusting the composition of the metallic solution (Optional) The process according to the invention may also advantageously include a step (e) of adjusting the composition of the extracted metal(s) solution, which consists of modifying said metal solution from step (b), (c), or (d) by adding and / or removing certain constituents. Metal precursors and / or organic additives may be added. Organic compounds used for metal extraction may also be removed, in whole or in part, if necessary. The objective is to obtain a metal solution whose composition corresponds to that desired for the impregnation solution used for the production of the recycled catalyst support according to the invention in the impregnation step (f) or in the suspension preparation step (i).

[0158] Case where several metals Ml of group VIII coexist on the source catalyst: Even if it is desired that the catalyst support according to the invention has a formulation identical to that of the source catalyst, the ratios between metals of the metal solution / extracted metal(s) are potentially to be adjusted, on the one hand because the step of removing at least part of the carbon - step (a) - from the catalyst can modify the initial metal contents of the source catalyst, and on the other hand because the extraction step (b) can induce different extraction rates for each of the metals.

[0159] The adjustment of the ratios between metals is done either by adding a makeup solution containing one or more of said metals, or by directly dissolving one or more metallic precursors in said metallic solution from the step (b), (c), or (d), the latter being preferred. As an example for metallic precursors of cobalt, the cobalt sources that can be used are advantageously chosen from among cobalt oxides, hydroxides, hydroxycarbonates, carbonates, and nitrates. Cobalt nitrate is preferred.

[0160] Case where the metal extraction solvent is in excess:

[0161] The extracted metal(s) solution from step (b), (c), or (d) may contain an excess of solvent relative to the desired impregnation solution. The ratios of organic compound to metals can be adjusted in two ways. The first way is to add a concentrated solution of metal precursors, or to dissolve these metal precursors directly to achieve the desired ratios. In this case, the final catalyst obtained will comprise a mixture of recycled and virgin metals.

[0162] If the excess solvent is too great to use the first method (i.e., the quantity of recycled metals incorporated into the final support is not significant, for example, less than 5% relative to the total quantity of target metals), the second method consists of removing all or part of the excess extraction solvent from the metal solution. In this case, the solvent can advantageously be recycled in step (b). Advantageously, in addition to the excess solvent, any organic compound is also recycled in step (b). For this purpose, any method known to those skilled in the art for separating a solvent from a metal solution is considered. Step (f)#: Impregnation

[0163] According to the invention, the process includes a step of preparing a catalyst support comprising at least one metal by a route which may include at least one step f) of impregnating a support with at least one impregnation solution from said solution of extracted metal(s) from step (b), (c), (d) or (e), to obtain an impregnated support, said extracted metal(s) remaining in liquid phase from extraction until impregnation.

[0164] In said step (f), a porous support, or a catalyst already containing one or more metals (according to the definition of "support" given above), is brought into contact with said solution of extracted metal(s) obtained in step (b), (c), (d), or (e). According to step (f), the contacting of said porous support or catalyst and the metal salt in solution can be carried out by any known method, such as, for example, ion exchange, dry impregnation, excess impregnation, vapor deposition, etc. The contacting can advantageously take place in one step or in several successive steps.

[0165] According to a preferred mode, step (f) of bringing said support into contact with said metallic solution is carried out by dry impregnation.

[0166] Dry impregnation consists of introducing a volume of impregnation solution equal to or slightly less than the porous volume of the support or catalyst. Dry impregnation allows the entirety of the impregnation solution's constituents to be deposited onto a given support or catalyst.

[0167] Step (f) can advantageously be carried out by one or more excess impregnations of solution or preferably by one or more dry impregnation(s), and, for example, by a single dry impregnation, using the impregnation solution.

[0168] According to a first embodiment, the impregnation of the substrate can be carried out using the solution of extracted metal(s) from step (b), (c), (d), or (e), and a supplement of at least one metal from Group VIII. The supplement can either be pre-added to the solution of extracted metal(s) for premixing, or added separately from the solution of extracted metal(s) to the device where the substrate impregnation is performed. The supplement can be in liquid or non-liquid form; it will more likely be in liquid form if added separately, and can be in liquid or solid form if added to the solution of extracted metal(s) prior to the actual impregnation.

[0169] Preferably, at least part of the extracted metal(s) solution obtained after any processing step of said extracted metal(s) solution can be reused, in particular as a supplement to said extraction solution. This limits the extraction solvent consumption of the process.

[0170] Preferably, the extracted metal(s) solution can be concentrated to remove at least some of the extraction solvent, and at least some of the removed solvent is then reused to make up the extraction solution. Again, this reuse helps to limit the extraction solvent consumption of the process.

[0171] The impregnation step (f) is advantageously carried out at a temperature between 10°C and 95°C, at a pressure between atmospheric pressure and 20 bar, preferably at atmospheric pressure, and for a duration preferably between 1 minute and 20 hours, preferably between 1 and 200 minutes. The impregnation step (f) is preferably carried out at a temperature between 10°C and 60°C, preferably at ambient temperature.

[0172] Advantageously, after each impregnation step, the impregnated support or catalyst is allowed to mature. Maturation allows the impregnation solution to disperse homogeneously within the support or catalyst.

[0173] Any maturation step described in the present invention is advantageously carried out at atmospheric pressure, in a water-saturated atmosphere, and at a temperature between 17°C and 50°C, and preferably at ambient temperature. Generally, a maturation time of between ten minutes and forty-eight hours, and preferably between thirty minutes and two hours, is sufficient.

[0174] In the embodiment in which step (f) is carried out via at least two impregnation cycles, each impregnation is advantageously followed by a drying step and a calcination step.

[0175] The support used in step (f) of the process according to the invention, advantageously comprising at least one oxide, is usually a porous solid selected from the group consisting of: aluminas, silica, and silica-aluminas. It may advantageously be obtained from step (h) of heat treatment applied to the metal-depleted catalyst obtained from step (b) of extraction.

[0176] The oxide support advantageously has a total pore volume of between 0.4 and 0.8 mL / g, preferably between 0.5 and 0.7 mL / g.

[0177] The specific surface area of ​​the oxide support is advantageously between 150 and 300 m².g', preferably between 100 and 250 m².g*, more preferably between 120 and 200 m².g*. The specific surface area is determined in the present invention by the BET method according to ASTM D3663.

[0178] The recycled catalyst oxide support according to the invention may advantageously be of the same nature as the source catalyst support, a description of which has already been given above.

[0179] In another preferred case, the oxide present in the support of said catalyst of the process according to the invention is an alumina-silica containing at least 80% by weight of alumina relative to the total weight of the composite support. The silica content in the support is advantageously at most 20% by weight relative to the total weight of the support, most often less than or equal to 15% by weight, preferably less than or equal to 10%.

[0180] According to a particularly preferred variant, the support consists of alumina, silica or silica-alumina.

[0181] Steps (g) of drying and calcining the impregnated support from step (f)

[0182] In accordance with the invention, said impregnation step f) is followed by at least a calcination step g) at a temperature above 700°C, preferably between 750 and 1300°C, most preferably between 800 and 1200°C, under an inert atmosphere (preferably under nitrogen) or under an atmosphere containing oxygen (preferably under air) so as to form a spinel between the group VIII metal (preferably cobalt) and the oxide support, preferably alumina, to form a support containing a mixed phase which may be, for example, cobalt aluminate.

[0183] This makes it possible to produce a so-called stabilized support.

[0184] The duration of said calcination step g) is advantageously between 0.5 between 2 a.m. and 4 p.m., preferably between 2 a.m. and 10 a.m. After this treatment, The metallic phase is thus generally found in oxide form. The catalyst support obtained after calcination has the advantage of containing stabilizing cobalt; therefore, no stabilization step of the support will be necessary to prepare the catalyst. The stabilized catalyst support will therefore be considered as a catalyst support stabilized with a 100% recycled cobalt solution.

[0185] According to the invention, the process includes a step of preparing a catalyst support comprising at least one metal by way which may include at least one step (h) of calcining at a temperature above 700°C the metal / metals depleted catalyst from step b) of extraction, but on which at least a part of the preferably group VIII metal of the source catalyst remains present.

[0186] Preferably, the residual metal content of the metal-depleted catalyst (sum of the contents of the different metals contained in said catalyst expressed as oxide) is less than 12% by weight, preferably less than 10% by weight and very preferably less than 7% by weight and greater than 3% and preferably greater than 5%.

[0187] The operating conditions of said step h) and the resulting solid are described in step g) of calcination.

[0188] Prior to said calcination step (h), the metal-depleted catalyst from step (b) advantageously undergoes a drying step at a temperature below 200°C, preferably between 50 and 180°C, more preferably between 70 and 150°C, and most preferably between 80 and 130°C. The drying step is preferably carried out for a duration of between 10 minutes and 10 hours. Longer durations are not excluded, but do not necessarily provide any improvement. The drying step can advantageously be carried out by any known technique. It is advantageously carried out at atmospheric pressure or reduced pressure. Preferably, this step is carried out at atmospheric pressure. It is advantageously carried out using air or any other hot gas. Preferably, the gas used is either air or an inert gas such as argon or nitrogen.Preferably, drying is carried out in the presence of nitrogen and / or air. Step (i) of preparing a suspension

[0189] According to the invention, the process includes a step of preparing a catalyst support comprising at least one metal by a route which may include a step (i) of preparing an acidic solution from at least a portion of said solution of extracted metal(s) and preferably from a suspension obtained by mixing all or part of the solution of extracted metal(s) and preferably cobalt when it advantageously contains an extraction solvent The acid is introduced during the synthesis of the support containing alumina and optionally silica. This aqueous cobalt solution is used for the preparation of the Fischer-Tropsch catalyst support. The solution is introduced during the mixing step of the precursors constituting the catalyst support. This solution advantageously has a pH between 2 and 4, i.e., a pH equivalent to that of the suspension required to prepare the catalyst support. Mixing this solution with the precursors results in a suspension with a pH between 2 and 4, and preferably between 2.5 and 3.5. Preferably, this solution is the sole source of cobalt in the suspension.The suspension produced in step (i) may consist largely of water and must contain an alumina source and optionally a silica source to maintain a Si / Al ratio ideally between 1 and 20, preferably between 1 and 10, and most preferably between 2 and 10. The alumina source ideally contains less than 1% sulfur and less than 1000 ppm Na, and preferably less than 0.1% S and less than 500 ppm Na. The silica source is preferably provided by silicic acid. The suspension is preferably prepared in a stirred tank known to those skilled in the art so that the suspension is homogeneous and pumpable for processing in step (j) of spray shaping.

[0190] Step (j) of shaping the support by atomization

[0191] The suspension produced in step (i) is then dried and shaped by spray drying in step (j). The suspension obtained from said solution has the advantage of not generating species that would require closed-circuit equipment for safety reasons, i.e., equipment with a sludge column or condenser. During the spray drying step (j), the spray drying temperatures are advantageously between 150 and 350°C. After the spray drying step, the dried catalyst support advantageously has a water content between 20% and 50%, and preferably between 25% and 35%. The objects obtained after the spray drying step (j) are advantageously in the form of compact spherical beads having a size distribution between 25 µm and 125 µm.

[0192] According to the invention, the support obtained at the end of step j) of atomization is then calcined in a step g') of calcination at a temperature above 700°C.

[0193] The operating conditions of said step g') and the resulting solid are described in step g) above.

[0194] Step j) of atomization advantageously provides a dried catalyst support containing cobalt. The support obtained by incorporating said solution presents the advantage of containing cobalt which will not need to be added during an additional step and in particular an impregnation step followed by a drying / calcination step to obtain a so-called stabilized support.

[0195] The active phase of the recycled catalyst targeted by the process according to the invention is generally of the same nature and quantity as that described above for the so-called spent catalyst. It is also possible to produce a recycled catalyst according to the invention that is less metal-rich than the spent catalyst used, particularly if this avoids concentrating the extract solution before impregnation.

[0196] The quantity of recycled metals contained in the catalyst according to the invention is between 1% and 100% wt of the metals contained in the catalyst produced according to the invention, preferably between 10% and 100% wt, preferably between 20% and 100% wt, and even more preferably between 50% and 100% wt of the metals contained in the catalyst according to the invention.

[0197] It should be noted that the catalyst produced according to the invention may have a different formulation from the spent catalyst used to recover the metals, and different quantities of metal and different metal ratios: thus, as mentioned above, a spent catalyst with a high metal content can, according to the invention, be used to produce a catalyst with a lower metal content (or vice versa). This makes it possible, where appropriate, to avoid a post-extraction solution concentration step at the end of step (b) or at least to reduce its intensity / duration.

[0198] In a preferred embodiment, said support preparation step is implemented according to the combination of steps f) g) and h).

[0199] In another preferred embodiment, said support preparation step is implemented according to steps i), j) and g'), alone.

[0200] Step (k): Impregnation of the catalyst support obtained at the end of one or the other of the calcination steps (h) and / or (g) and / or (g').

[0201] According to the invention, the process advantageously includes at least one step k) - of impregnating the support obtained at the end of the preparation step according to one of the ways of said step or according to the combination of at least 2 of the ways with a solution of metal of group VIII not from the extraction step.

[0202] Preferably, the process advantageously comprises at least one step k) – impregnating the support obtained at the end of the preparation step according to one of the methods of said step or according to a combination of at least two of the methods with a fresh or conventional solution of a Group VIII metal or with a metallic solution derived from so-called fresh metal precursors. A “conventional” impregnation solution is understood to be a “fresh” solution containing, in a known manner, precursors of a Group VIII metal, preferably “fresh” cobalt precursors, i.e., not recycled according to the process of the present invention.

[0203] In said step (k), the recycled catalyst support, which already contains one or more metals and is therefore stabilized (according to the definition of "stabilized support" given above), is brought into contact with said solution. According to step (k), the contacting of said porous support or of said catalyst and the metal salt in solution can be carried out by any known method, such as, for example, ion exchange, dry impregnation, excess impregnation, vapor deposition, etc. The contacting can advantageously take place in one step or in several successive steps.

[0204] According to a preferred mode, the step (k) of bringing said support into contact with said metallic solution is carried out by dry impregnation.

[0205] Dry impregnation consists of introducing a volume of impregnation solution equal to or slightly less than the porous volume of the support or catalyst. Dry impregnation allows all the constituents of the impregnation solution to be deposited onto a given support or catalyst.

[0206] Step (k) can advantageously be carried out by one or more excess impregnations of solution or preferably by one or more dry impregnation(s), and, for example, by a single dry impregnation, using the impregnation solution.

[0207] Step (k) is advantageously carried out at a temperature between 10°C and 95°C, at a pressure between atmospheric pressure and 20 bar, preferably at atmospheric pressure, and for a duration preferably between 1 minute and 20 hours, preferably between 1 and 200 minutes. Step (k) is preferably carried out at a temperature between 10°C and 60°C, preferably at ambient temperature.

[0208] Advantageously, after each impregnation step, the impregnated support or catalyst is allowed to mature. Maturation allows the impregnation solution to disperse homogeneously within the support or catalyst.

[0209] Any maturation step described in the present invention is advantageously carried out at atmospheric pressure, in a water-saturated atmosphere, and at a temperature between 17°C and 50°C, and preferably at ambient temperature. Generally, a maturation time of between ten minutes and forty-eight hours, and preferably between thirty minutes and two hours, is sufficient.

[0210] In the embodiment in which step (k) is carried out via at least two impregnation cycles, each impregnation is advantageously followed by a drying step and a calcination step (1).

[0211] Step (1): drying and calcination of the recycled catalyst support then impregnated during step (k)

[0212] According to the invention, the impregnated recycled catalyst support from step k) is subjected to a drying step and a calcination step so as to obtain a recycled catalyst according to the invention.

[0213] Preferably, the drying step of the impregnated substrate from step k) is carried out at a temperature below 200°C, preferably between 50 and 180°C, more preferably between 70 and 150°C, and most preferably between 80 and 130°C. The drying step is preferably carried out for a duration of between 10 minutes and 10 hours. Longer durations are not excluded, but do not necessarily provide any improvement. The drying step can advantageously be carried out by any known technique. It is advantageously carried out at atmospheric pressure or reduced pressure. Preferably, this step is carried out at atmospheric pressure. It is advantageously carried out using air or any other hot gas. Preferably, the gas used is either air or an inert gas such as argon or nitrogen.Preferably, drying is carried out in the presence of nitrogen and / or air and is advantageously performed in a fluidized bed.

[0214] According to the invention, drying is followed by a calcination step. This eliminates any organic extraction compounds and / or any counter-ions present. Following the drying step, a calcination step is advantageously carried out at a temperature between 300°C and 600°C, preferably between 350°C and 450°C, under an inert atmosphere (nitrogen, for example) or under an atmosphere containing oxygen (air, for example). The duration of this heat treatment is advantageously between 0.5 hours and 16 hours, preferably between 1 hour and 6 hours. After this treatment, the active phase is generally in oxide form.

[0215] The active phase of the recycled catalyst targeted by the process according to the invention is generally of the same nature and quantity as that already described above for the so-called used source catalyst. It may also be possible to produce a recycled catalyst according to the invention that is less metal-rich than the used source catalyst, particularly if this avoids concentrating the extract solution before impregnation.

[0216] The quantity of recycled metals contained in the catalyst according to the invention is between 1% and 100% wt of the metals contained in the catalyst produced according to the invention, preferably between 10% and 100% wt, preferably between 20% and 100% wt, of the metals contained in the catalyst according to the invention.

[0217] It should be emphasized that the catalyst produced according to the invention may have a different formulation from the used source catalyst used to recover the metals and different quantities of metal and different ratios between metals: thus, as mentioned above, a used catalyst heavily loaded with metals can according to the invention be used to produce a catalyst with a lower metal load (or vice versa). This makes it possible, where appropriate, to avoid a step of concentrating the solution after extraction at the end of step (b) or at least to reduce its intensity / duration.

[0218] Step (m): step of activation of the recycled catalyst by reduction

[0219] Before its use in the Fischer-Tropsch process, the recycled catalyst produced by the process according to the invention undergoes an activation step, preferably by reduction. The activation is preferably carried out in a reducing medium, i.e., in the presence of hydrogen, in order to transform the metal oxides into metal, preferably Co. The activation is advantageously carried out by injecting a flow containing hydrogen, and preferably pure hydrogen, onto the catalyst. This activation can advantageously be carried out in situ or ex situ (inside or outside the reactor) of the Fischer-Tropsch process reactor, preferably ex situ according to the invention, at temperatures between 200 and 600°C, and more preferably between 300 and 500°C.

[0220] The examples illustrate the invention without limiting its scope. EXAMPLES

[0221] Example 1 (according to the invention): obtaining a metal-depleted solid no. 1 and a cobalt solution no. 1

[0222] We start with a spent Fischer-Tropsch catalyst containing cobalt on a silica alumina support used in a slurry Fischer-Tropsch process. The catalyst is in the form of a powder with an average particle size of 80 µm. It was unloaded and coated with solid hydrocarbon products at room temperature produced by the Fischer-Tropsch reaction (waxes). It was then washed by a Soxhlet in the presence of xylene heated to its boiling point for 7 hours. After this treatment, this catalyst, called the washed catalyst, contains 7.8 wt% carbon.

[0223] The washed catalyst contains cobalt. The composition of the catalyst is expressed in terms of oxides and referred to the mass of dry catalyst: 23.4 wt% CoO (18.4 wt% cobalt).

[0224] A step for extracting cobalt from this washed catalyst is carried out on a laboratory scale: 10 g of this washed catalyst and 25 g of extraction solution are introduced into an Erlenmeyer flask. The extraction solution is an aqueous solution containing 176 g / L of citric acid. The Erlenmeyer flask is then placed on a stirring table, and the mixture is stirred for 5.5 h at room temperature. The mixture is then filtered through sintered glass with a porosity of 5 µm to recover an aqueous cobalt solution, referred to as solution no. 1, and a solid residue containing the metal-depleted catalyst (Co). Analysis of the solution shows that it contains 50 g / L of cobalt. The calculated Co extraction rate is 72%. The catalyst metal-depleted, called depleted catalyst no. 1, then contains 6.6% CoO by weight (5.1% cobalt by weight).

[0225] Example 2 (comparative): obtaining a metal-depleted solid No. 2 and a cobalt solution No. 2

[0226] A washed catalyst as described in Example 1 is regenerated under a flow of oxygen-depleted air (10%) by means of a heat treatment at a temperature > 300°C, following a gradual temperature ramp (temperature ramp of 1°C / min between 200 and 350°C, 2°C / min from 350 to 550°C, then 4°C / min from 550 to 650°C, with a 30-minute hold every 50°C), followed by a hold at 650°C for 2 hours to avoid exothermic reaction due to the combustion of hydrocarbons and coke present in the spent catalyst. At the end of this treatment, it contains 0.03 wt% carbon and will be called a washed-regenerated catalyst.

[0227] The washed-regenerated catalyst contains cobalt. The composition of the catalyst is expressed in terms of oxides and referred to the mass of dry catalyst: 25% by weight of CoO (20% by weight of cobalt.

[0228] A step of extracting cobalt from this regenerated catalyst is carried out on a laboratory scale: 10 g of this washed-regenerated catalyst and 25 g of extraction solution are introduced into an Erlenmeyer flask. The extraction solution is an aqueous solution containing 176 g / L of citric acid. The Erlenmeyer flask is then placed on a stirring table, and the mixture is stirred for 5.5 h at room temperature. The mixture is then filtered through sintered glass with a porosity of 5 to recover an aqueous cobalt solution on the one hand and a solid residue on the other. Analysis of the solution shows that it contains 4.5 g / L of cobalt. The calculated Co extraction rate is 7%. The metal-depleted catalyst, referred to as depleted catalyst no. 1, then contains 23.6 wt% CoO (18.6 wt% cobalt).

[0229] Table 1 below summarizes the rate of cobalt extracted as a function of the initial carbon content and the carbon contents of the cobalt-depleted catalysts for Examples 1 and 2.

[0230] [Table] 1 Example 1 Example 2 Initial carbon content (% wt) 7.8 0.03 Solution #1 2 Cobalt concentration g / L 50 4.5 Cobalt extraction rate t(%) 72 7 Metal-depleted catalyst #1 2%CO on the depleted catalyst (%wt) 5.1 18.6

[0231] Example 4 (according to the invention): preparation of catalyst A from the metal-depleted catalyst No. 1

[0232] The metal-depleted catalyst No. 1 obtained in Example 1 is calcined at 900°C for 8 hours after a temperature ramp of 10°C / minute to obtain a so-called stabilized support No. 1. A commercial aqueous cobalt nitrate solution containing 13 wt% cobalt is then dry-impregnated onto the so-called stabilized support No. 1. The resulting solid is then dried at 100°C for 4 hours in air, and then calcined at 400°C for 2 hours. The total cobalt content of the resulting solid is 13 wt%. This operation is repeated once to obtain a Fischer-Tropsch catalyst precursor containing 21 wt% cobalt. This catalyst precursor is then reduced under pure hydrogen for 16h at 400°C after a temperature ramp of 4°C / min, then discharged under inert material and coated in nC22 to protect it from re-oxidation.

[0233] Example 5 (non-compliant): preparation of catalyst B from metal-depleted catalyst No. 2

[0234] The metal-depleted catalyst No. 2 obtained in Example 2 is calcined at 900°C for 8 hours after a temperature ramp of 10°C / minute to obtain a so-called stabilized support No. 2. A commercial aqueous cobalt nitrate solution containing 13 wt% cobalt is dry-impregnated onto the so-called stabilized support No. 2. The resulting solid is then dried at 100°C for 4 hours in air, and then calcined at 400°C for 2 hours. The total cobalt content of the resulting solid is 21 wt%. This catalyst precursor is then reduced under pure hydrogen for 16 hours at 400°C after a temperature ramp of 4°C / min, then discharged under an inert material and coated in nC22 to protect it from reoxidation.

[0235] Example 6 (according to the invention): preparation of Catalyst C from a stabilized Fischer-Tropsch catalyst support obtained by dry impregnation of solution no. 1 obtained in example 1 onto a fresh support:

[0236] Solution No. 1 obtained in Example 1 is used after evaporating 40% of the water volume of the solution using a rotary evaporator. The solution is maintained at a temperature of 50°C before being dry-impregnated onto a Siralox 5 silica alumina support. The resulting solid is then calcined at 900°C for 8 hours after a temperature ramp of 10°C / minute to obtain a so-called stabilized support No. 3. The cobalt content of the stabilized support obtained is 5 wt%. A commercial aqueous solution of cobalt nitrate containing 13 wt% cobalt is The solid is dry-impregnated onto the so-called stabilized support #3. It is then dried at 100°C for 4 hours in air, and then calcined at 400°C for 2 hours. The total cobalt content of the resulting solid is 13 wt%. This operation is repeated once to obtain a Fischer-Tropsch catalyst precursor containing 21 wt% cobalt. This catalyst precursor is then reduced under pure hydrogen for 16 hours at 400°C after a temperature ramp of 4°C / min, then discharged under an inert material and coated in nC22 to protect it from reoxidation.

[0237] Example 7 (according to the invention): Preparation of a catalyst D obtained from a stabilized support No. 4 comprising Co prepared by atomizing a suspension based on solution No. 1

[0238] Solution No. 1 is used to prepare the suspension for atomization to obtain the stabilized catalyst support No. 4. The following precursors are introduced into a stirred tank in the proportions mentioned: 58% water, 9% commercial boehmite, 12% silicic acid, 20% of said solution No. 1, and 1% nitric acid. After a homogenization time of 5 hours, the suspension is atomized at a temperature of 250 °C to obtain solid, homogeneous dried beads with a residual water content of 35%. The dried catalyst support is then calcined at a temperature of 900 °C to obtain the stabilized catalyst support containing 5% Co. The stabilized support No. 4 has a bead size ranging from 25 µm to 125 µm.

[0239] A commercial aqueous cobalt nitrate solution containing 13 wt% cobalt is dry-impregnated onto the so-called stabilized support No. 4. The resulting solid is then dried at 100°C for 4 hours in air, and then calcined at 400°C for 2 hours. The total cobalt content of the resulting solid is 13 wt%. This operation is repeated once to obtain a Fischer-Tropsch catalyst precursor containing 21 wt% cobalt. This catalyst precursor is then reduced under pure hydrogen for 16 hours at 400°C after a temperature ramp of 4°C / min, then discharged under an inert material and coated in nC22 to protect it from reoxidation.

[0240] Example 5: Evaluation of the catalytic performance of catalysts A, B (non-compliant), C and D.

[0241] The Fischer-Tropsch synthesis reaction is carried out in a continuous slurry reactor operating with a 10% (vol) concentration of catalyst in the slurry phase. Each catalyst is in powder form with a diameter between 40 and 150 microns. The test conditions are as follows:

[0242] Temperature = 230°C

[0243] Total pressure = 2 MPa

[0244] H2 / CO molar ratio = 2

[0245] CO conversion is maintained between 45 and 50% throughout the test. Syngas flow rates are adjusted so as to be at iso CO conversion regardless of catalyst activity.

[0246] The intrinsic activity of the catalyst kO can be calculated as a function of a reference temperature, called Tref, and a pre-exponential reference factor kr

[0247] With Ea= 119.51375 kJ / mol, R=8.314 J / mol / K and kr=0.003 mol / s.

[0248] The activity ratio between two catalysts can thus be expressed as a temperature difference, relative to a catalyst chosen as a reference base of activity kO, base.

[0249] By arbitrarily choosing 225°C as the reference temperature, the activity of the catalyst chosen as the base is expressed using the equation below: kO, base=

[0250] A model allows the determination of the reference temperature Tref, enabling the convergence of experimental and calculated carbon monoxide consumption rates. From the reference temperature (Tref) thus obtained, the activity ratio relative to the catalyst chosen as the reference base is calculated using the formula:

[0251] Activity(%)=k0 / k0base*100= exp(-EaR(l / 4-98.15-l / Tref)

[0252] The results were calculated for catalysts A and B and are shown in Table 2 below. The alpha paraffin selectivities are also given, as well as the selectivity for methane and C5+ compounds.

[0253] The measurement of the selectivity in alpha paraffin is done via gas chromatography analysis of the reaction effluents, determination of paraffins and calculation of the slope of the curve log mol (%) = f(number of carbon) which corresponds to alpha.

[0254] The results in Table 2 show that the catalytic performance of catalysts A, C, and D is equivalent in terms of both activity and selectivity, taking into account the uncertainties related to the implementation of a catalytic test and the accuracy of the analyses for preparations according to the invention. However, in the case of the preparation on a metal-depleted support not according to the invention, the performance of catalyst B is lower in terms of both activity and selectivity.

[0255] [Tables2] Catalyst Activity relative to approximately 150h (%) Methane selectivity (%) C5+ selectivity Catalyst A (according to the invention) 405 8.2 84 Catalyst B (comparative) 300 9.1 80 Catalyst C (according to the invention) 400 7.3 85 Catalyst D (according to the invention) 420 7.8 84

Claims

1. Demands A process for producing a recycled catalyst support comprising at least one metal, preferably from Group VIII and not comprising any metal from Group VIB, characterized in that said process comprises the recycling of at least a portion of one or both of the constituent elements of a source catalyst, namely the support or the metal M1, preferably from Group VIII, the process comprising at least: - a step for removing at least part of the carbon present on the source catalyst comprising at least one washing step (A1) of the source catalyst with an organic solvent, and / or at least one heat treatment step (A2) of the source catalyst at a temperature below 300°C in the presence of a gas containing air, without a heat treatment step in the presence of a gas selected from oxygen and hydrogen, at a temperature above 300°C prior to the extraction step, - Then, an extraction (B) by an extraction solution of the metal Ml and possibly of another metal chosen from the metals of group VIII and / or of the boron of said catalyst from the step of removing at least part of the carbon, to obtain a solution of extracted metal(s), and a catalyst depleted in metal(s), - then a step of preparing a catalyst support comprising at least one metal, preferably from group VIII, according to one of the following methods or according to a combination of at least 2 of the following methods: - at least one impregnation step (F) of a support by at least one impregnation solution derived from said solution of extracted metal(s), to obtain an impregnated support, said extracted metal(s) remaining in liquid phase from extraction until impregnation, followed by at least one calcination step (G) at a temperature above 700°C, - at least one calcination step (H) at a temperature above 700°C of the metal / metal depleted catalyst from the extraction step, - a preparation step (I) of an acidic solution from at least a part of said solution of extracted metal(s) and its atomization to obtain an atomized support which is then calcined at a temperature above 700°C, - at least one impregnation step (K) of the support obtained at the end of the preparation step according to one of the routes of said step or according to the combination of at least 2 of the routes by a solution of metal of group VIII not from the extraction step, - a drying step and a calcination step (L) of the impregnated support.

2. A method according to claim 1, wherein the metal Ml of group VIII is Cobalt.

3. A method according to claim 1 or 2 wherein the support for the source catalyst is made of alumina, silica or silica-alumina.

4. A process according to any one of the preceding claims wherein the source catalyst also comprises, in addition to the group VIII metal Ml, another group VIII metal preferably selected from platinum, palladium, ruthenium, and rhenium, alone or in mixture.

5. A process according to any one of claims 1 to 4 wherein the washing step (Al) of the source catalyst is carried out in the presence of an organic solvent maintained at its boiling point, selected from aromatic solvents preferably toluene and / or xylene, linear hydrocarbon solvents comprising between 3 and 12 carbon atoms preferably hexane and / or heptane, and linear or branched alcohols comprising between 3 and 12 carbon atoms, alone or in mixture.

6. A method according to any one of claims 1 to 5 wherein the heat treatment step (A2) is carried out after the washing step in the presence of a gas containing oxygen and at a temperature preferably between 100 and 300°C, preferably between 150 and 300°C and most preferably between 200 and 270°C.

7. A process according to any one of claims 1 to 6 wherein the extraction solution for the group VIII metal Ml used in the extraction step comprises a polar protic solvent, preferably selected from the group formed by methanol, ethanol, and water, or alternatively a mixture of water-ethanol, water-methanol or water-citric acid.

8. A method according to any one of the preceding claims, wherein said method comprises at least one step of processing the solution of metal / metals extracted before its use in the impregnation step, chosen from at least one of the following treatments: purification (C), concentration (D), adjustment of the composition (E) of said solution dilution.

9. A process according to any one of the preceding claims wherein the calcination step(s) of the different paths of the catalyst support preparation step is / are carried out at a higher temperature between 750 and 1300°C, most preferably between 800 and 1200°C, under an inert atmosphere or under an atmosphere containing oxygen.

10. A process according to any one of the preceding claims, wherein said support preparation step is carried out by combining the steps of at least one impregnation of a support with at least one impregnation solution from said solution of extracted metal(s), to obtain an impregnated support, said extracted metal(s) remaining in liquid phase from extraction until impregnation, followed by at least one calcination step at a temperature above 700°C, and at least one calcination step at a temperature above 700°C of the metal(s) depleted catalyst from the extraction step.

11. A method according to any one of claims 1 to 9 wherein said support preparation step is carried out by a step of preparing an acid solution from at least a portion of said solution of extracted metal(s) and atomizing it to obtain an atomized support which is then calcined at a temperature above 700°C, alone.

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